(navigation image)
Home American Libraries | Canadian Libraries | Universal Library | Community Texts | Project Gutenberg | Biodiversity Heritage Library | Children's Library | Additional Collections
Search: Advanced Search
Anonymous User (login or join us)
Upload
See other formats

Full text of "Massachusetts Fuel and Gas Code"

248 CMR: BOARD OF STATE EXAMINERS 
OF PLUMBERS AND GAS FITTERS 



248 CMR 4.00: INTRODUCTION AND MASSACHUSETTS MODMCATIONS 

Section 



4.01 
4.02 
4.03 



Scope and Purpose 

Definitions 

Adoption of Relevant Codes and Overview of Modifications 



4.01 : Scope and Purpose 

248 CMR 4.00 governs the Board's adoption of the ANSI Z223. 1-2002 NFPA-54-2002 
National Fuel Gas Code 2002 Edition and NFPA 58 Liquefied Petroleum Gas Code 2001 Edition 
and the modifications which comprise the Massachusetts Fuel and Gas Code. 

4.02: Definitions 

As used in 248 CMR 4.00 through 7.00. 

NFPA-54 . The ANSI Z223. 1-2002 NFPA-54-2002 National Fuel Gas Code 2002 Edition. 

NFPA-58 . The NFPA 58 Liquefied Petroleum Gas Code 2001 Edition. 
4.03: Adoption of Relevant Codes and Overview of Modifications 

(1) Adoption of Relevant Codes : The Massachusetts Fuel Gas Code shall be: 

(a) The ANSI Z223.I-2002 NFPA-54-2002 National Fuel Gas Code 2002 Edition as 
modified in 248 CMR 4.00 and 248 CMR 5.00. A copy of ANSI Z223. 1-2002 NFPA-54- 
2002 National Fuel Gas Code 2002 Edition may be obtained from any national bookstore 
chain. 

(b) The NFPA 58 Liquefied Petroleum Gas Code 2001 Edition as modified in 248 CMR 
4.00. A copy of NFPA 58 Liquefied Petroleum Gas Code 2001 Edition may be obtained 
from any national bookstore chain. 

(c) 248 CMR 7.00 Massachusetts Code for Gas Utilization Equipment in Large Boilers. 

(2) Overview of Modifications . 

(a) Order of Precedence : 

1. 248 CMR 3.00 through 10.00 shall take precedence when there is a conflict between 
248 CMR 3.00 through 10.00 and the NFPA-54. 

2. 248 CMR 3.00 through 10.00 shall take precedence when there is a conflict between 
248 CMR 3.00 through 10.00 and the NFPA-58. 

3. In the event of a conflict between the 2002 Edition of NFPA-54-ANSI Z223.1 
National Fuel Gas Code as modified in 248 CMR 4.00 and 248 CMR 5.00 and the 2001 
Edition of the NFPA 58 Standard for the Storage and Handling of Liquefied Petroleum 
Gases as modified in 248 CMR 4.00, the 2002 Edition of NFPA-54-ANSI Z223.1 
National Fuel Gas Code with the modifications made in 248 CMR 4.00 and 5.00 shall 
take precedence over the 2001 Edition of the NFPA 58 Standard for the Storage and 
Handling of Liquefied Petroleum Gases with the modifications in 248 CMR 4.00. 

(b) Modifications to NI^^PA 58 - NFPA 58-2001 Standard for the Storage and Handling 
of Liquefied Petroleum Gases shall be modified as follows: 

1 . Chapters 1 , 2, and 3 as they apply to the use of Liquefied Petroleum Gas Systems not 
covered in NFPA-54-ANSIZ223 . 1 , 2002 have been adopted as the Code governing these 
systems. 

2. Reference to Storage Containers in Chapters 1, 2,and 3 are not adopted by the Board 
given that FPR 527 CMR 6.00 governs Storage Containers. 

3 . Reference to Engine Fuel Systems and LP-Gas Systems on Vehicles in Chapter 3 are 
not adopted by the Board. 

(c) NFPA-54- ANSI Z223.1 -2002 the National Fuel Gas Code shall be modified as 
follows: 

1 . Delete pages i through iv and substitute the following: 

In accordance with the provisions of M.G.L. c. 142, § 13, the. Board makes the 
following rules and regulations relative to the installation of fuel gas piping systems, fuel 
gas utilization equipment, and related accessories throughout the Commonwealth. 

3/11/05 248 CMR -25 



248 CMR: BOARD OF STATE EXAMINERS 
OF PLUMBERS AND GAS FITTERS 



4.03: continued 

Nothing in 248 CMR 3.00 through 7.00 shall conflict with the provisions of 
220 CMR Department ofTelecommunication and Energy lOO.OOthrough 113.00ofthe 
Massachusetts Gas Distribution Code and nothing in 248 CMR shall supersede or 
overrule any of the provisions of M.G.L. c. 142 or any code, rules, or regulations 
established under the authority of M.G.L. c. 142. 

Rule 1 ■ Gas piping systems, in general, shall be low pressure (not in excess of '/2 pound 
per square inch or 14 inches water column). 

Rule 2 . The requirements of 248 CMR 3.00 shall apply to all gas fitting work performed 
in the Commonwealth. 

Rule 3 . In cases of emergency a gas appliance may be turned on temporarily by the 
licensed installer provided: 

a. the installer has tested the piping in accordance with the appropriate section of 
248 CMR; 

b. the installer and the supplier are satisfied that the installation of piping and use 
of the equipment will assure safe operation; and 

c. the Inspector (or the chief inspector if more than one inspector) is notified and a 
regular Inspection is made at the earliest opportunity but not later than the next 
working day. 

Rule 4 . Undiluted Liquefied Petroleum Gas: (Propane Gas) 

a. No deliveries of propane gas shall be made to any new or altered gas piping 
installation without the supplier first ascertaining whether the Inspector has approved 
the permit and Inspected the installation. 

b. Alterations or additions to the original gas piping installation shall require re- 
approval and issuance of new permits. 

Rule 5 . Each trailer that is used in any way for human occupancy and incorporates a gas 
piping system shall be inspected by the Inspector in every location and relocation where 
such trailer is in use and reconnected to a fuel gas source that is regulated by 248 CMR 
3.00 through 7.00. 

Rule 6 . For the purpose of 248 CMR, the Inspector shall be either the Local or State 
Inspector as determined under 248 CMR 3.00. 

Rule 7 . An amendment to Title 49 CFR, Code of Federal Regulations Part 192, 
Subpart A - General Section 192.3 Definitions of the minimum Federal Safety Standards 
relating to transportation of Natural Gas and other Gas by Pipeline redefine a service line 
to mean a distribution line that transports gas from a common source to: 

a. A customer meter or the connection to a customer's piping, whichever is farther 
downstream; or 

b. The connection to a customer's piping if there is no customer meter. A customer 
meter is the meter that measures the transfer of gas from an operator to a customer. 

Rule 8 . Exception to PeiTnit Requirements of 248 CMR 3.00 . No peiTnit shall be 
required for: 

a. The adjusting of gas appliance controls, the adjusting of gas flames, the 
replacement of gas controls, the installation or replacing of gas meters and regulators, 
and the servicing of gas appliances shall be deemed work for which no permit shall 
be required. 

b. The restoration of gas service after a gas meter or meter fit is relocated under the 
following rules: 

i. The work shall be done by authorized employees of gas companies organized 

under M.G.L. c. 164. 

ii The required gas pipiiig reconnection shall not exceed ten feet. 

iii. The gas piping reconnections shall be labeled by the installing gas company. 



3/11/05 248 CMR -26 




248 CMR: BOARD OF STATE EXAMINERS 
OF PLUMBERS AND GAS FITTERS 



4.03: continued 

Rule 9 . Gas shall not be turned on to a new or existing system, which has been renovated 
unless the installation has been Inspected and approved by the Inspector as required 
under 248 CMR 3.00. 

Rule 10 . Whenever there is reason to believe that the gas system of any building or 
structure has become defective, it shall be subjected to test and/or Inspections, any 
defects found shall be corrected as required in writing by the Inspector. 

Rule 11 . Whenever additional gas piping connections or alterations thereof are being 
made or installed in existing buildings or premises, and existing gas fitting is found to 
be in violation of 248 CMR to the point of being a health menace, nuisance or a safety 
hazard, such existing gas fitting shall be made compliant with 248 CMR 3.00 through 
7.00 before any additional work may be completed. 

Rule 12 . In addition to the requirements of 248 CMR 3.00 through 7.00, when gas 
equipment, which is connected to a gas system, is to be permanently removed and/or 
replaced, a permit for the work shall be secured. All connections to such equipment shall 
be made gas tight by use of a plug or cap. 

Rule 13 . Should a licensed plumber or gas fitter holding a gas permit for installation of 
gas work turn on gas to such work without first notifying the Inspector, he may not be 
granted any further gas permits upon the discretion of the Inspector. 

Rule 14 . Surveyed . Priortothecommencement of work, all portions of existing systems 
that are directly affected by proposed gas fitting work shall be surveyed by the licensed 
plumber or gas fitter to insure that the existing work is adequate to support the proposed 
work. 

Rule 15 . In the case of a fire or explosion involving facilities or buildings regulated by 
the Board, the Inspector shall in reasonable detail promptly notify the Board and the 
Serving Gas Supplier. The Inspector or authorized agent of the State Fire Marshall shall 
impound any gas piping or gas equipment involved in the incident which in his or her 
opinion contributed in any way to the explosion or fire. 

Rule 16 . Utility Gas and Undiluted Liquefied Petroleum Gas systems within the same 
building; 

a. Utility gas and L.P^ gas systems shall not be installed within the same building 
except where the Board has first granted Special-Permission under 248 CMR 3.00. 

b. When the two gas systems are installed within the same building, the natural gas 
piping system shall be color-coded yellow and the L. P. gas piping system colored 
green. 

c. Labeling : The gas piping systems shall be labeled: 
i at a minimum of every ten feet; 

ii. at all changes of direction; 

iii. on each side of a penetration through a partition, wall or ceiling; and, 

iv. at every gas shutoff valve. 

v. The labels shall be: 

(i) colored yellow with black lettering, indicating the type of gas and the 
pressure contained within the piping system, and 

(ii) the letters shall be sized so that the labeling can be read from a normal 
line of vision when standing at the main floor level. 

Rule 17 . The Limited Liquefied Petroleum Gas Installer shall be responsible for the gas 
permits when installing, connecting, and moving liquefied petroleum gas salamanders, 
space heaters and related equipment used in buildings under construction. 

Rule 18 . A secondary meter assembly from utility gas companies is allowed down 
stream of a master meter subject to all permits, testing, rules, and regulations. 



3/11/05 248 CMR -27 



248 CMR: BOAJID OF STATE EXAMINERS 
OF PLUMBERS AND GAS FITTERS 



4.03: continued 

Rule 19 . Gas piping systems, for gas utilization equipment over 12,500,000 BTU/hour 
and water tube boilers having outputs of 10,000 pounds of steam per hour or more 
require: 

a. that Special-permission by the Board be obtained before installation. 

b. That the plans bear the seal of a Massachusetts Registered Professional Engineer. 

c. That accompanying the plans is a letter from the servicing gas supplier indicating 
that the fuel supply is available. 

Rule 20 . Gas piping systems for cogeneration facilities require: 

a. Special-pennission from the Board prior to installation. 

b. That the plans bear the seal of a Massachusetts Registered Professional Engineer. 

c . That accompanying the plans is a letter from the servicing gas supplier indicating 
that the fuel supply is available. 

Rule 21 . Repairs and Alterations . 

a. In existing buildings or premises where gas piping installations are to be altered, 
replaced, repaired, or renovated, deviations from the provisions of 248 CMR 3.00 
through 7,00 are permitted, provided such deviations are found to conform to the 
intent of 248 CMR 3.00 through 7.00, and are approved by the Inspector. 

b. Whenever compliance with the provisions of 248 CMR 3.00 through 7.00 fails 
to eliminate or alleviate a nuisance which may involve health or safety hazards, the 
owner or his or her agent shall install such additional gas utilization equipment as 
may be found necessary by the Inspector. 

. c. The intent of 248 CMR 4.03 Rule 21a. and b. shall apply only when a hardship 
occurs due to mechanical or structural limitations, and when extreme circumstances 
warrant special terras or conditions in the opinion of the Inspector and the servicing 
gas supplier. 

i. Deviations from the provisions of the code may be permitted in existing 
building or premises where gas fitting installations are to be altered, repaired, or 
renovated. The deviations shall be negotiated by the permit holder and the 
Inspector prior to the installation. The deviations may be allowed provided that 
the deviations are found necessary and conform to the scope and intent of 
248 CMR. 

ii. Whenever the work subject to a permit complies with the provisions of 
248 CMR 3.00 through 10.00, but the Inspector notes other existing plumbing or 
gas fitting that may cause a health or safety hazard, the Inspector shall notify the 
owner of the hazard in writing. 

Rule 22 . For gas utilization equipment in boilers or with burners having inputs that 
exceed 400,000 BTU/hour per combustion chamber refer to 248 CMR 7.00, 
Massachusetts Code for Gas Utilization Equipment in Large Boilers. 

Rule 23 . Work on a gas supply systems at a point upstream of the outlet of the meter set 
assembly or the service regulator when a meter is not provided; 

a. Serving Gas Supplier . No person, unless in the employment of or having 
permission from the sei^ving gas supplier, shall open or make connections with a gas 
distribution main. 

b. Service Gas Piping . When a gas meter is not provided, no persons, unless in the 
employment of or having permission from the serving gas supplier, shall: 

i. repair, 

ii. alter, 

iii. open or make connections to the service gas piping, or 

iv. do any other work on the parts of the gas supply distribution system up to 

and including the meter set assembly, or the service regulator. 

c. Meter or Service Regulator When a Meter is not Provided . 

i. No person, unless in the employment of or having permission from the serving 
gas supplier, shall discormect the inlet of the gas meter, or service regulator when 
a meter is not provided, or move such a meter or regulator. 



3/11/05 248 CMR -28 



4.03: continued 



248 CMR; BOARD OF STATE EXAMINERS 
OF PLUMBERS AND GAS FITTERS 



ii. A gas fitter or plumber may disconnect the piping from the outlet side of such 
a meter or regulator. He or she shall remake the joint at the meter, or service 
regulator outlet when a meter is not provided, carefully replacing all insulating 
fittings or insulating parts of such fittings, and shall leave the gas turned off at the 
meter or regulator. 

d. Notify Serving Gas Supplier of Any Repairs Needed . In the case of any work 
performed by a gas fitter or plumber that discloses the need for repairs or alterations 
on any part of the gas supply system, the serving gas supplier shall be notified 
promptly of this fact. 

e. Notify Serving Gas Supplier of Any Leaks . If gas is leaking from any part of the 
gas supply system, a gas fitter or plumber not in the employment of the serving gas 
supplier may make the necessary repairs and shall promptly notify the Inspector and 
serving gas supplier. 

Rule 24 . The Board must certify the installer of a field installed automatic gas vent 
damper. 

Rule 25 . Penalties and Appeals . 

a. Penalty . See 248 CMR 3.00 for penalty provisions. 

b. Appeal Procedure . See 248 CMR 3.00 for appeal procedure. 



REGULATORY AUTHORITY 

248 CMR 4.00: M.G.L. c. 112, §61; M.G.L c. 142, §§ 13 and 21. 



3/11/05 248 CMR -29 



248 CMR: BOARD OF STATE EXAMINERS 
OF PLUMBERS AND GAS FITTERS 



NON-TEXT PAGE 



3/11/05 248 CMR -30 



248 CMR: BOARD OF STATE EXAMINERS 
OF PLUMBERS AND GAS FITTERS 



248 CMR 5.00: AMENDMENTS TO 2002 EDITION OF ANSI Z223. l-NFPA-54 

Section 

5.01: Scope and Purpose 

5.02: 248 CMR 5.02 Modifications to sections of NFPA-54, Chapter 1 

5.03: 248 CMR 5.03 Modifications to sections of NFPA-54, Chapter 5 

5.04: 248 CMR 5.04 Modifications to NFPA-54, Chapter 6 

5.05: 248 CMR 5.05 Modifications to NFPA-54, Chapter 7 

5.06: 248 CMR 5.06 Modifications to NFPA-54, Chapter 8 

5.07: 248 CMR 5.07 Modifications to NFPA-54, Chapter 9 

5.08: 248 CMR 5.08 Modifications to NFPA-54, Chapter 10 

5.09: 248 CMR 5.09 Modifications to NFPA-54, Chapter 1 1 

5.01 : Scope and Purpose 

248 CMR governs the Board's modifications to NFPA-54. 

5.02: Modifications to Sections of NFPA-54. Chanter 1 

(1) Revise NFPA-54 section 1.1.1.1(A) as follows. 

Coverage of piping systems shall extend form the point of delivery to the connections with 
each gas utilization device. For other than undiluted liquefied petroleum gas systems, the 
point of delivery shall be considered the outlet of the service meter assembly or the outlet of 
the service regulator or service shut off valve where no meter is provided. For undiluted 
liquefied petroleum gas systems, the point of delivery shall be considered the outlet of the 
first stage regulator. 

(2) Revise NFPA-54 section 1.1.1.1(B) as follows. 

All Gas piping systems, in general for all buildings and structures shall be low pressure (not 
in excess of Vi P.S.I.G. or 14 inch water column) All low pressure gas piping systems shall 
be designed using a maximum 0.5 inch water column pressure drop. Special-permission 
pursuant to 248 CMR 3.00 may be granted for elevated pressure (greater than Vi P.S.I.G. or 
14 inch water column) when gas utilization equipment specifically requires higher pressure 
or when a designed low pressure system requires pipe sizes in excess of four inch I.P.S. An 
elevated pressure Special-permission request form specified by the Board shall be filled out 
completely and submitted to the Executive Secretary for the Board. If the Board grants 
Special-permission, a copy shall be filed with the Inspector before the commencement of any 
work. 

(3) Revise NFPA-54 section 1.1.1 .2.( 1 3) as follows. 

All Undiluted Liquefied Petroleum or Natural gas piping connections installed for the 
purpose of providing temporary heat in or adjacent to buildings or structures under 
construction or renovation shall comply with 248 CMR 3.00 through 7.00: 

,(4) Revise NFPA-54 section 1.1.2 as follows. Amend the first sentence to read: 

Other Standards: In applying NFTPA - 54, reference should also be made to the 
manufacturer's instructions, the serving gas supplier regulations, and local building, heating, 
plumbing or other codes in effect in the area in which the installation is made, 

5.03: Modifications to sections of NFPA-54. Chapter 5 

(1) Revise NFPA-54 section 5. 1.1 as follows: 

Permits and Piping Plans. 



12/30/05 248 CMR -31 



248 CMR: BOARD OF STATE EXAMINERS 
OF PLUMBERS AND GAS FITTERS 



5.03: continued 



(a) In addition to the permit requirements of 248 CMR 3.05, for gas installations of over 
5,000,000 BTU/Hr the following is required: 

1. A plan of the proposed piping system and equipment shall be submitted for approval 
to the Inspector. 

2. This plan shall contain a written statement from the local gas supplier that such fuel 
. demand is available. 

3. The system shall be designed by a Registered Professional Engineer. 

(b) Gas piping systems requiring gas pressure in excess of Vi P.S.I.G. require Special- 
permission of the Board before being installed. This Special-permission requirement does 
not apply to propane gas piping systems that are between the first and second stage regulator 
if the second stage regulator is located outside the building. 

(2) Revise NFPA-54 section 5.4.2.1 by adding a last sentence and table as follows: 

Diversity factor is an important factor determining the correct gas piping size to be used for 
supplying domestic ranges in multiple family dwellings; it applies to domestic ranges only 
and shall not apply to any other gas appliances. 

TABLE 

Multi-Family Dwellings 

Diversity Factor in Percent of Total Load for 

Domestic Gas Ranges with connected Load Ratings 

of 63,000 Btu/hr. or more per Range 



No. of Ranges 


Demand cubic 
ft/hour 


Percent of 
Rating 


No. of Ranges 


Demand cubic 
ft/hour 


Percent of 
Ratings 


1 


63 


100 


13 


270 


33 


2 


107 


85 


14 


283 


32 


3 


132 


70 


15 


293 


31 


4 


151 


60 


16 


312 


31 


5 


173 


55 


17 


332 


30 


6 


189 


50 


18 


340 


30 


7 


198 


50 


19 


346 


29 


8 


212 


42 


20 


353 


28 


9 


225 


39 


21 


358 


27 


10 


233 


31 


22 


374 


27 


11 


243 


37 


23 


390 • 


27 


12 


257 


35 


24 & Over 


408 


• 27 



(3) Replace NFPA-54 section 5.5. 1 with the following: 

Elevated Pressure Piping to be Labeled: Piping supplying gas at a pressure greater than V2 
P.S.LG. or 14 inch water column shall be labeled: 

(a) at a minimum of every ten feet; 

(b) at all changes of direction; 

(c) on each side of a penetration through a partition, wall or ceiling; and, 

(d) at every gas shutoff valve. 

(e) The labels shall: 

1. be colored yellow with black lettering; 

2. indicate the type of gas and the pressure contained within the piping system; and 

3. the letters shall be sized so that the labeling can be read from a normal line of 
vision when standing at the main floor level. 

(4) Revise NFPA-54 section 5.6.2.1 as follows:. 

Cast-iron and Galvanized Pipe and pipe fittings shall not be used. 



3/1 1/05 



248 CMR - 32 



248 CMR: BOARD OF STATE EXAMINERS 
OF PLUMBERS AND GAS FITTERS 



5.03: continued 

(5) Replace NFPA-54 section 5.6.2.2 with the following. 

Steel and Wrought-Iron. 

(a) Steel and wrought-iron pipe shall be at least of standard weight (schedule 40) and 
shall comply with one of the following standards: 

1 . ANSI/ASME B36. 10, Welded and Seamless Wrought-Steel Pipe 

2. ASTM A 53, Standard Specification for Pipe, Steel, Black and Hot Dipped, Zinc- 
Coated Welded and Seamless. 

3. ASTM A 106, Standard Specification for Seamless Carbon Steel Pipe for High- 
Temperature Service. 

(b) Welding of gas piping systetns with pressures under or equal to 70 P.S.I.G shall be 
performed according to the following; 

1 . Welding will be performed by a qualified welder who is a licensed plumber or 
gas fitter, or under the direct supervision of a licensed plumber or gas fitter. The 
welding shall conform to a Welding Procedure Specification (WPS), accompanied 
by a Procedure Qualification Record ( PQR), which will be available to the Inspector. 
■2. The WPS and PQR must be in accordance with one of the following: 

a. American Welding Society (AWS) B2. 1 

b. American Petroleum Institute (API) 1104 

c. ASME Section DC 

3. The installation shall meet the following Inspection criteria: 

a. A visual Inspection as to the quality of the weld shall be performed in 
accordance with AWS D 1.1 or API 1 104 standards 

b. The test pressure used during an Inspection shall comply with the following: 
i. Systems with a maximum operating pressure of ten P.S.I.G. or less, shaD 
be tested to a minimum of three P.S.I.G. or ten times the operating pressure, 
whichever is greater. 

ii. Systems with an operating pressure greater than ten P.S.I.G. and less than 
70 P.S.I.G. shall be tested at 100 P.S.I.G. 

iii. The test duration shall be one hour for every 100 feet of pipe, or 
fraction thereof. The minimum test duration shall be one hour and the 
maximum test duration shall be 24 hours, irrespective of system design. 

(c) Welding on gas piping systems with pressures over 70 P.S.I.G. shall be performed 
according to the following: 

1 . All welds shall be full penetration and performed by a qualified welder. 

2. All welds shall be subjected to a 100% X-ray or 100% Ultrasonic Examination 
(UT) test. 

3. The manifolding in any combination of gas regulators and relief vents is 
prohibited 

4. All Socket Welded Type Joints on gas piping supplying pressures over 70 
P.S.I.G. shall require a magnetic particle test or other recognized non-destructive test. 

5. The gas piping system shall be pressure tested to a minimum of 1.25 times the 
gas piping systems working pressure. 

a. The test duration shall be a minimum of one hour. 

b. The test shall be witnessed by the Inspector. 

6. The testing company and their authorized field agent that provides the (UT) field 
examination shall be certified by a recognized and accredited agency in such testing. 

A copy of the AWS certification shall be submitted to the Board prior to the 
examination. 

7. Repairs that are made to welded joints that fail the X-Ray or (UT) test shall be 
re-tested and re-certified. For future reference; the failed welded joint that is re- 
tested shall be identified by stenciling Vi inch high white lettering at the weld 
location the date of the re-test. 

8. The Board shall require an affidavit signed by the individual who performed the 
X-ray or (UT) examination for the testing agency. The affidavit shall state that all 
welds meet the requirements of the Welding Procedure Specification (WPS) and that 
all welds passed the X-Ray or (UT) examination. 



3/11/05 248 CMR -33 



248 CMR: BOARD OF STATE EXAMINERS 
OF PLUMBERS AND GAS FITTERS 



5.03: continued 

(6) Replace NFPA-54 section 5.6.3.4 with the following: 

For purposes of this section CSST shall mean corrugated stainless steel tubing systems. 

Corrugated stainless steel tubing systems must be tested and listed in accordance with ANSI/ 
LC- 1 -/CS A 6.26 and installed by manufacmrer trained, licensed plumbers and gas fitters The 
system shall be sized in accordance with NFPA-54 - ANSI Z233. 1 - 2002. 

(a) CSST Fittings. All fittings and accessories used in the installation of CSST piping 
systems shall be approved by the CSST manufacturer for use with their system. 

(b) CSST Concealed Fittings: 

1. Where gas piping is to be concealed: 

a. connections shall only be made with CSST fittings listed for use in concealed 
spaces; and 

b. connections shall be produced by the manufacturer of the CSST piping 
system. 

2. Malleable fittings shall be permitted in concealed locations when used in 
combination with CSST fittings. 

3. For each malleable fitting there shall only be a single CSST connection. 

(c) Repairs to Concealed CSST Piping: 

1. Repairs required in a CSST system which is concealed, or otherwise not readily 
accessible, shall be repaired with a fitting hsted for the CSST system being used. 

2. Installation of an access panel shall be required at the repair site. 

(d) Interior Meter Connections: Interior meter connections may be directly connected 
to the CSST system as long as the meter is securely affixed to the building, and the CSST 
is secured to the building structure when 24 inches or more of tubing is exposed. 

(e) Exterior Meter Connections: 

1 . No CSST shall be connected to an exterior meter. 

2. The tubing shall terminate at the foundation wall with a termination fitting, and 
the meter shall be rigidly connected with steel piping to the building structure. 

(f) Sleeved Gas CSST: 

1 . CSST shall be sleeved when passing through a metal or concrete deck to protect 
the integrity of the mbing and be fire - stopped in accordance with the State Building 
Code. 

2. The sleeve shall be Schedule 40 black or galvanized pipe and shall extend a 
minimum six inches from the top of the finished floor and the underside of the deck, 

(g) Only manifolds for CSST systems supplied and listed by the CSST manufacturer 
may be concealed. 

1 . Assembled manifolds shall be installed in an accessible location as defined in the 
2002NFGC-Z223.1. 

2. Assembled manifold is a piping combination made up of close nipples and 
malleable tees. 

(h) Fireplace Log Installations: 

1 . CSST shall terminate with a termination fitting at the entrance to the masonry fire 
box. 

2. The workmanship shall be performed and completed in such a manner so that the 
termination will not be exposed to any adverse effects. 

(i) Fixed Appliance Connection Using CSST: CSST may be directly connected to a 
fixed appliance when the following conditions are met. 

1 . The tubing is securely attached to the building structure or other means of solid 

support. 
. 2. Tubing shall not run exposed for a distance greater than or equal to 30 inches 

without being physically attached to the building stmcture or other means of solid 

support. 

3. CSST terminates with a proper fitting and gas cock, 
(j) CSST Used Underground: 

1 . When in contact with the earth or other material that could corrode the piping, the 
CSST shall be installed within a sleeve designed to withstand the superimposed 
loads. 



3/11/05 248 CMR -34 



5.03: continued 



248 CMR: BOARD OF STATE EXAMINERS 
OF PLUMBERS AND GAS FITTERS 



2. Except for pre-engineered sleeves that are Product-approved by the Board, the 
sleeve shall allow free movement of the CSST. 

3. All sleeve ends shall be sealed liquid tight. 

4. An acceptable tape marking system shall be in place no more than six inches from 
the top of the grade indicating that a gas line is below. 

5. The minimum depth for buried gas piping as describe herein is 18 inches from 
the top of grade and the minimum size of the CSST to be buried is % inch. 

(k) CSST Used as an Appliance Connection: CSST shall not be used as a flexible 

•appliance connector downstream of the appliance shutoff device. 

(I) Sizing CSST Systems: CSST systems shall be sized and installed with a maximum 

14 inch water column (Vi P.S.I.G.) gas pressure unless Special -permission has been 

granted by the Board. 

(m) CSST Installation and Modifications: Installation of CSST in the Commonwealth 

of Massachusetts shall be in strict compliance with the manufacturer's instructions and 

the Massachusetts State Plumbing and Gas Code 248 CMR 3.00 through 7.00. 

(n) Testing Requirements for CSST Systems: 

1. Before any piping is covered, when CSST piping systems are installed in new 
construction or remodeling, the system shall be tested as part of the Inspection as 
prescribed under NFPA-54 Chapter 7.1 as modified under 248 CMR 5.05. 

2. Before piping is connected to any appliance the licensed plumber or gas fitter 
shall do a second test of the system. 

3. A tag shall be: 

a. affixed to the meter or service manifold acknowledging this test; and 

b. signed and dated by the licensed plumber or gas fitter. 

(o) Liquid Leak Detector: No corrosive liquids shall be used in the testing of the CSST 

system. Some household soaps and detergents may be corrosive to gas and plumbing 

products. 

(p) Exposed CSST. Tubing: When CSST is installed outdoors or is subject to corrosive 

chemicals, exposed stainless CSST tubing (where the jacket has been removed) shall be 

recovered with tape as specified by the CSST manufacturer. (After the completion of 

testing.) 

(q) CSST Piping Installed on Roofs: CSST shall be installed for roof top equipment 

only when it is supported by one of the following methods: 

1 . The CSST tubing with a UV stabilized jacket is supported the full length of the 
CSST run. 

a. The tubing shall be affixed to a wooden plank or a steel channel that is 
securely attached by an appropriate method every six feet to the roof structure. 

b. The tubing shall be attached directly to the support every six-feet. 

2. The CSST tubing is installed within a metal or plastic conduit that is securely 
attached by an appropriate method every six feet to the roof structure. Where the 
piping system requires a tee to be installed within the line, the sleeve shall terminate 
no more than 12 inches from the tee on both runs and the branch line. 

3. For CSST tubing having sizes of IV2 inch and two inches and having a UV 
stabilized jacket, the following requirements shall be satisfied: 

a. the CSST shall be supported on blocks which are spaced not more than 48 
inches apart. 

b. The blocks shall be constructed of materials appropriate for outdoor 
conditions and shall be securely attached by an appropriate method to the roof 
structure, and 

. c. The method used to attach the CSST to the block shall not damage the plastic 
coating. 

4. The maximum length of tubing not supported by any method listed shall not 
exceed 30-inches when connected to a gas fired roof top unit or similar gas 
equipment. 



3/11/05 248 CMR -35 



248 CMR: BOARD OF STATE EXAMINERS 
OF PLUMBERS AND GAS FITTERS 



5.03: continued 

(7) ReviseNFPA-54section5.6.7.4by replacing it with the following: 

Thread Compounds: Thread (joint) compounds (pipe dope) and pipe thread sealing tape 
(Teflon, etc.) shall be resistant to the actions of liquefied petroleum gas or to any other 
chemical constituents of the gases to be conducted through the piping. 

(8) Revise NFPA-54 section 5. 1 2 as follows: 

5.12 Acceptable Shutoff Devices: Gas Cocks and Ball Valves installed for use shall either 
be listed by a nationally recognized testing agency or comply with applicable American 
Standard Approval or Listing Requirements and shall be Product-Approved by the Board. 
They shall: 

(a) Have clearly indicated open and closed positions and rigidly secured stops to limit 
both extremes of rotation. W.O.G. Ball Valves lever or Tee Handle Type are acceptable. 

(b) Show no evidence of leakage when subjected to an air pressure test of a six inch 
mercury column (3 P.S.I.G.) for ten minutes. 

(c) Be capable of withstanding without deformation, breakage or leakage the following 
"Turning Effort" standards when screwed onto a pipe fitting: 

NOMINAL PIPE SIZE TURNING EFFORT 

Vi inch 300 inch-pounds 

Vi inch 450 inch-pounds 

1 inch 600 inch-pounds 
VA inch 700 inch-pounds 
I'/zinch 750 inch-pounds . 

2 inch 950 inch-pounds 
2^2 inch 1050 inch-pounds 

3 inch 1050 inch-pounds 

(d) Have a capacity not less than that specified in the following table for 0.60 Specific 
Gravity, 1000 BTU Per Cubic Foot Gas at 1.0 inch water column pressure drop. 

NOMINAL PIPE SIZE MINIMUM CAPACITX 

»/2inch 260,000 BTU Per hour 

3/4 inch 698,000 BTU Per hour 

1 inch 1,1 92,000 BTU Per hour 
Wa inch 1,768,000 BTU Per hour 
P/zinch 3,097,000 BTU Per hour 

2 inch 5,346,000 BTU Per hour 
21/2 inch 6,859,000 BTU Per hour 

3 inch 11,923,000 BTU Per hour 

(e) Each valve shall be marked in a conspicuous place with the manufacturer's name or 
trademark. 

(Testing procedures for 5. 12(b), (c), and (d) shall be consistent with those outlined in the 
American National Standard for Manually Operated Gas Valves). 

(9) After NFPA-54 section 5.13 add a new section 5. 14 as follows: 

5.14 Installation of Consumer-owned Gas Pressure Boosters. 

(a) When Special -permission has been granted by the Board and the serving gas supplier 
has granted its approval, consumer owned gas pressure boosters may be installed in that 
portion of the gas piping system extending from the outlet of the meter set assembly to 
the inlet of the equipment requiring the elevated pressure. 

(b) Hermetically Sealed: Gas pressure boosters shall be of the hermetically sealed type. 
Any exception to this provision shall be noted in the applicant's Special-Permission 
request to the Board. 

3/11/05 248 CMR -36 



5.03: continued 



248 CMR: BOARD OF STATE EXAMINERS 
OF PLUMBERS AND GAS FITTERS 



(c) Proper Location: 

1 . Gas pressure boosters shall be installed on a firm foundation or concrete floor and 
shall be free of vibration. 

2. Gas pressure boosters shall be located in well-ventilated spaces and readily 
accessible for examination, replacement or necessary maintenance. 

(d) Underpressure Protection Device: A manual reset low pressure shutoff device shall 
be installed between the gas pressure booster and the gas meter to protect against a 
reduction in supply pressure lower than that acceptable to the serving gas supplier. 

(e) Additional Provisions: 

1 . Gas pressure boosters shall be installed and maintained in accordance with the 
manufacturer's instructions. 

2. The gas equipment for which the booster is required, shall be equipped with a 
properly set, low gas pressure switch that will prove the correct pressure is available 
before startup. 

3. Check valves shall be installed to prevent the increased pressure from 
pressurizing the system upstream of the booster. Where bypasses are installed they 
shall include a shutoff valve and a check valve. 

4. A pressure regulator to maintain a constant outlet pressure shall be installed 
immediately downstream of the booster (exception: not required if the booster has 
an integral pressure regulator). 

5.04: Modifications to NFPA-54. Chapter 6 

(1) After NFPA-54 section 6.1.6 add a new sub-section 6.1.6.1 as follows; 

Minimum Size: Threaded gas piping underground shall be % inch iron pipe size on low- 
pressure gas systems. Installation shall conform to Section 6.1 Piping Underground. 

(2) After NFPA - 54 section 6.3.1 add a new sub-section 6.3. 1. 1 as follows: 

Minimum Size: No gas piping smaller than standard Yi inch iron pipe size shall be installed 
in any concealed location. 

(3) After NFPA -54 section 6.3.4 add a new section 6.3.4.1 as follows: 



CSST installed vertically and horizontally in concealed wall spaces or partitions of 2 X 4 
construction that does not penetrate the walls, floors or partitions shall be protected in 
accordance with 248 CMR 5.04: Table Il-a. 







Table II- a 


Profection of 
Tubing Orientation 


CSST Tubing Installed in Concealed Wall Spaces of 2 X 4 Construction 


Insulation 


Tubing Size 


and Location 


Type 


< 1-inch 


> 1-inch 


Vertical Interior 


None 


1. Single runs only. 


Same as CSST < in and CSST 


Wall 




2. Tubing not secured to structure. 


manufacturer specified 






3. CSST manufacturer specified 


shielding device along entire 






strilce plates at points of penetration. 


length in concealed space. 






4. CSST Strike plates on both sides 








of wall. 




Horizontal Interior 


None 


CSST manufacturer specified shielding device along length between 


Wall 




studs and strike plates at points of penetration on both sides of wall. 


Vertical Exterior 


Non-Rigid 


1. Single runs only. 


Same as CSST < in and CSST 


Wall 


(Fiberglass) 


2. Tubing not secured to structure. 


manufacturer specified 






3. Tubing installed between insula- 


shielding device along entire 






tion and wall board. 


length in concealed space. 






4. CSST manufacturer specified 








strike plates at points of penetration 




Vertical Exterior 


Rigid 


Schedule 40 pipe or CSST manufacturer specified shielding device 


Wall 




along entire length and at points of penetration. 



3/11/05 



248 CMR - 37 



248 CMR: BOARD OF STATE EXAMINERS 
OF PLUMBERS AND GAS FITTERS 



5.05: Modifications to NFPA-54. Chapter 7 

(1) Revise NFPA-54 section 7.1 as follows: 

Pressure Testing and Inspection: 

(a) Inspection of the rough gas system: Inspections shall conform to the requirements 
of 248 CMR 3.00 in addition to the following: 

1. Before any gas piping system is put into service, it shall be tested in the presence 
of the Inspector to insure that it meets the requirements of 248 CMR. Where any 
part of the gas piping system is to be enclosed or concealed, the test shall be 
conducted prior to the covering of any portion of the gas piping system. The test 
medium shall be air or other inert gas {e.g. nitrogen, carbon dioxide). OXYGEN 
SHALL NEVER BE USED. 

2. Gas piping systems, not in excess of Vi P.S.I.G. or 14 inches water column, 
extending from the outlet of the meter set assembly to the closed shutoff valve of 
each appliances shall withstand a pressure of at least six inches mercury or three 
pounds gauge for a period of not less than ten minutes without showing any drop in 
pressure. Pressure shall be measured with a mercury manometer, slope gauge or an 
equivalent device so calibrated as to be read in increments of not greater than 1/10 
pound. The source of pressure shall be isolated before the pressure tests are made. 

3. If an additional appliance is connected to a gas piping system previously installed, 
the additional piping shall be isolated and tested to a pressure of at least six inches 
of mercury or three pounds gauge for a period of not less than ten minutes without 
showing any drop in pressure and the remainder of the piping system previously 
installed may be tested to not more than three inches of mercury or 1 Vz pounds gauge 
for a period of not less than ten minutes without showing any drop in pressure. 

4. Gas piping systems for industrial and other large installations shall be tested at 
a pressure at least ten times (maximum 100 P.S.I.G.) the proposed maximum 
working pressure. Test duration shall be long enough to determine if there are any 
leaks but not less than one hour for each 100 linear feet of pipe or fraction thereof. 
The duration of the test need not exceed 24 hours irrespective of system design. 

5. Gas piping systems for undiluted liquefied petroleum gases. Such gas piping 
systems shall be tested at a pressure no less than IV2 times the proposed working 
pressure, but not less than three P.S.I.G. for not less than ten minutes without the 
gauge showing any drop in pressure, irrespective of design pressure. 

6. All piping before the. second stage low pressure regulator in undiluted liquefied 
petroleum gas systems shall be tested using a pressure not less than the maximum 
operating pressure of the tank or container, for a period of not less than ten minutes 
without any drop in pressure. 

(b) Inspection of Final Gas System: 

1. After the test of the rough piping for tightness as described in 248 CMR 
5.05(l)(a) gas may be turned on and appliances tested at normal operating pressure 
by means: 

a. of a non-corrosive foaming agent test; or 

b. by the use of an electronic leak detector. 

2. Following the testing and approval of a gas system, the Inspector shall attach a 
permanent tag in a conspicuous place indicating that the system has passed 
Inspection. 

5.06: Modifications to NFPA-54. Chapter 8 

( 1 ) Revise NFPA-54 section 8 . 1 . 1 as follows : 

Appliances, Accessories and Equipment to comply with Standard Requirements. All gas 
appliances, accessories and gas utilization equipment shall comply as follows. 

(a) All residential and commercial appliances shall be listed by a nationally recognized 
testing agency, constructed in accordance with applicable American National Standards 
Institute (ANSI), and Product-approved by the Board. 



3/11/05 . 248 CMR -38 



248 CMR: BOARD OF STATE EXAMINERS 
OF PLUMBERS AND GAS FITTERS 



5.06: continued 



(b) Commercial and industrial equipment that is not certified by a nationally recognized 
testing agency acceptable to the Board shall not be installed unless Special-permission 
has been granted by the Board or the Lispector has granted his or her approval prior to 
the installation. Such installation, if allowed, shall be in accordance with NFPA-54 
Chapter 1 1 entitled Procedures for the Initial Operation of Industrial Gas Equipment as 

., modified by 248 CMR 5.09. 

(c) A List of Reference Standards acceptable to the Board is provided in Appendix A 
of NFPA-54. It may be referred to for the installation of specific equipment. 

(2) Add new NFPA-54 section 8. L 10.4: 

Direct Vent Appliances, as defined in Section 3.3.68, may be installed. 

(3) Add the following language after the last paragraph of NFPA-54 section 8.1. II. 2: 
Exception No. 3: Direct Vent Appliances, as defined in Section 3.3.68 may be installed. 

(4) Revise NFPA-54 section 8.1.22 as follows: 

(a) The installing agency shall conform to the equipment manufacturers specific 
recommendations in completing an installation that will provide satisfactory performance and 
semceability. 

(b) The installing agency shall also leave the manufacturer's installation, operating and 
maintenance instructions in a location at the premises where they will be readily available 
for reference and guidance of the authority having jurisdiction, the Inspector, serviceperson 
and the owner or operator. 

(c) When required by the Inspector, a copy of the manufacturer's installation, operating and 
maintenance instructions shall be given to said authority for review within two working days 
prior to calling for a fmal Inspection. 

(5) Revise NFPA-54 8.5.1 as follows: Add to sub-section (3) as follows: 

(a) In addition to being Product-approved under 248 CMR 3.00, flexible appliance 
connectors shall meet the requirements of ANSI Z21.24 and shall be approved by a 
nationally recognized testing agency recognized by the Board. 

(b) The maximum length of a connector shall not exceed 36 inches. 

(c) A flexible connector shall not be installed where it will be subject to physical or thermal 
damage. 

(d) A flexible appliance connector shall not be used on gas pressure in excess of V2 pound 
per square inch gauge (P.S.i.G.). 

(e) An accessible shutoff valve shall be located on rigid piping upstream of a flexible 
connector. 

(f) Only one flexible connector shall be used for connecting each appliance. 

(g) A flexible connector shall not be re-used except for disconnecting and reconnecting the 
original appliance for servicing. 

(h) A flexible connector shall not extend from one room to another nor pass through any 
walls, partitions, ceilings or floors. 

(6) Revise NFPA-54 section 8.5.4 as follows: Add at the end 

Laboratories or similar spaces in Schools, Colleges, Universities or similar occupancies or 
classrooms where gas burning laboratory type equipment is used by students shall be 
equipped with a single readily accessible emergency master shutoff valve located within the 
laboratory or space. This valve shall be kept closed except during periods of equipment use. 
This provision shall also apply whenever alterations to existing gas systems are made. 



3/11/05 248 CMR -39 



248 CMR: BOARD OF STATE EXAMINERS 
OF PLUMBERS AND GAS FTTTERS 



5.07: Modifications to NFFA-54. Chapter 9 

(1) Revise NFPA-54 section 9.1 by adding the following last sentence: 

Unlisted equipment or accessories shall be prohibited unless Product-approval is granted by 
the Board or the Inspector. 

(2) Revise NFPA-54 section 9. 1.2 by replacing it with the following language: 

Gas utilization equipment shall not be installed so its combustion, ventilation and dilution 
air is obtained from a bedroom or bathroom. EXCEPTION: Type 1 dryers may be installed 
in bathrooms when air for combustion and ventilation is introduced to the space according 
to the following: 

(a) The minimum size of the single air intake shall be equal to the size of the exhaust 
vent of the di7er. 

(b) The air for combustion shall not be obtained from a bedroom or bathroom. 

(c) The air for combustion shall be obtained from a space that is sized according to 8.3. 

(d) The dr)'er is installed according to 9.4. 

(3) Revise NFPA-54 9.6. 1 by replacing it to read as follows: 

Decorative appliances for installation in vented fireplaces that are installed in bedrooms or 
bathrooms shall be of the type that obtain all air for combustion directly from the outdoors. 
When decorative appliances are installed in vented fireplaces, the flue damper must be 
removed or welded in a fully open position. 

(4) Revise NFPA-54 section 9.7.1 to read as follows: 

Vented gas fireplaces that are installed in bedrooms or bathrooms shall be of the types and 
design that obtain all air for combustion directly from the outdoors. 

(5) Revise NFPA-54 section 9.8.1 by adding a second sentence as follows: 

The specifications for Non- Re-circulating Direct Gas-fired Industrial Air Heaters shall 
require that there be no more than 50 P.P.M. of Carbon Monoxide in the total volume of air 
discharged from the unit. 

(6) Revise NFPA-54 section 9.8.2 to read as follows: Non-Re-circulating Direct Gas-fired 
Industrial Air Heaters shall not be used to supply any area containing sleeping quarters or places 
of public assembly. These units are intended for use in industrial and commercial occupancies, 
such as commercial kitchens, factories, and warehouses where there is direct relief. All other 
installations require Special-perjmission by the Board. 

(7) After NFPA-54 section 9.9. 1 add a new sub-section 9.9. 1 . 1 as follows: 

The specifications for Re-circulating Direct Gas-fired Industrial Air Heaters shall require that 
there be no more than 50 P.P.M. of Carbon Monoxide in the total volume of air discharged 
from the unit. . 

(8) Revise NFPA-54 section 9.9.2.1 to read as follows: 

Re-circulating Direct Gas-fired Industrial Air Heaters shall not be used to supply any area 
containing sleeping quarters or places of public assembly. These units are intended for use 
in industrial and commercial occupancies, such as factories and warehouses where there is 
direct relief. All other installations require Special-permission by the Board. 



3/11/05 248 CMR -40 



248 CMR: BOARD OF STATE EXAMINERS 
OF PLUMBERS AND GAS FITTERS 



5.07: continued 

(9) After NFPA-54 section 9.12.8 add a new section, 9. 12.9 as follows: 

Thermally Actuated Gas Shutoff Valves Used for Commercial Cooking Equipment (In-Line 
Gas Valves). 

When in-line gas valves are used in junction with a fire protection/suppression system, 
the installation of these valves shall conform to the following: 

(a) Only a licensed plumber or gas fitter shall install an in-line gas valve in new or 
existing gas piping for the purpose of shutting off the gas supply to commercial cooking 
equipment. 

(b) All in-line gas valves shall be mechanical type with manual reset and shall be 
installed in close proximity to the cooking equipment and shall shut off the gas supply 
to the equipment served by the hood and duct system protected by the 
extinguisher/suppression system. 

(c) A plan of the 'Mechanical Fuel Shutoff System" shall be submitted to the Inspector 
prior to any installation. 

(d) If a wiring and gas piping plan in which an electrically operated gas valve is 
necessary for certain equipment it shall be submitted to the Board for Special-permission. 
When Special-permission has been granted by the Board, a copy of this plan shall be 
submitted to the Inspector. 

(e) When an in-line gas valve is used in conjunction with a fire prevention suppression 
system, a permanent notice shall be posted at the reset device and gas meter or propane 
regulator cautioning the operator to shut off the gas to all appliances before resetting the 
device. 

(f) Actuation of the in-line gas valve shall be made in the presence of the Inspector at 
the time of the gas piping tests. 

(g) An annual inspection certificate shall be submitted to the. Inspector certifying that 
the in-line gas valve is in working condition. 

(h) In any case not covered by these provisions, contact the Board for a ruling. 

(10) Add a new NFPA-54 section 9.12.10 as follows: 

Unlisted Food Service Equipment or accessories shall be prohibited unless Product-approved 
by the Board. 

(a) The use of gas range ovens, broilers, or top burners for space heating shall be 
prohibited. 

(b) The installation of gas ranges with match-lit ovens shall be prohibited. 

(c) The installation of any listed or unlisted commercial cooking range without a listed 
type oven safety pilot shall be prohibited. 

(1 1) Revise and replace NFPA-54 section 9.23.1 as follows: 

(a) Prohibited Installations: Unvented room heaters shall not be installed in bathrooms 
or bedrooms. 

(b) Only direct vented appliances, (see definition 3.3.68) shall be installed in sleeping 
quarters, bedrooms and bathropms and shall be installed in accordance with 248 CMR 
3.00 though 7.00. 

(12) After NFPA-54 section 9.23.4 add a new section. 9.23.5 as follows: 

Un-vented Room Heaters shall be installed in accordance with 527 CMR 30.00 and 
248 CMR 3.00 through 7.00: 

(a) Permits and Inspections: In addition to complying with 248 CMR 3.05 the following 
requirements must be satisfied; 

1 . A permit shall be obtained from the head of the fire department and the local or 
state gas inspector having jurisdiction for the installation of all unvented propane or 
natural gas-fired space/room heaters. 



3/11/05 248 CMR -41 



248 CMR: BOARD OF STATE EXAMINERS 
OF PLUMBERS AND GAS FITTERS 



5.07: continued 



2. The permits shall be conditioned upon final inspection and approval of 
installation by the head of the fire department and the local or state gas inspector 
having jurisdiction. 

3. A copy of the manufacturer's installation/operating literature shall be submitted 
with each permit application. 

4. Before operation, the Head of the Fire Department and the local or state gas 
inspector shall inspect the installation for compliance with 527 CMR (Board of Fire 
Prevention Regulations) and 248 CMR (Board of State Examiners of Plumbers and 
Gas Fitters). 

5. A final inspection by the state or local gas inspector of the unvented space/room 
heater shall not be performed until proof is provided that the head of the fire 
department having jurisdiction has granted a permit. 

(b) Unvented propane or natural gas-fired space/room. heaters shall conform to ANSI 
Z21.11.2, be equipped with an oxygen depletion safety (ODS) shuioff system and be 
Product-approved in accordance with 248 CMR. 

(c) Unvented propane or natural gas-fired space/room heaters shall be installed in 
accordance with their listings and the manufacturer's instructions. Proper clearances to 
combustibles shall be maintained. In no case shall the clearances be such as to interfere 
with combustion air and accessibility. 

(d) Installations shall be of a permanent type, with a permanently piped fuel supply in 
accordance with 248 CMR. LPG appliances shall be subject to the storage requirements 
in accordance with 527 CMR 6.00. Portable unvented propane or natural gas-fired 
space/room heaters shall be prohibited. 

(e) Unvented propane or natural gas-fu-ed space/room heaters shall be prohibited in 
bedrooms and bathrooms. 

(f) Space/room heaters shall be properly sized for the room or space of installation, but 
shall not exceed a maximum of 40,000 BTU input per room or space. 

(g) In occupancies with an unvented propane or natural gas-fired space/room heater, no 
less than one listed carbon monoxide detector that is installed in accordance with the 
manufacturers instructions shall be installed and maintained near the space where the 
heater is located. 

1 . Any building wherein the heater is to be installed shall, as a precondition to such 
installation, have working smoke detectors installed and maintained in accordance 
with the requirements of 780 CMR (State Board of Building Regulations and 
Standards) in effect at the time of construction or; 

2. If no requirement was in effect at the time of construction the smoke detector 
shall be compliant and installed as provided for in M.G.L. c. 148, § 26E. 

(h) In rooms and buildings served by an unvented propane or natural gas-fired 
space/room heater, a primary source of heat, which is operable, shall be permanently 
installed and maintained in the building in accordance with 105 CMR (Department of 
Pubhc Health). 

(i) Sellers of unvented propane or natural gas-fired space/room heaters shall provide to 
each purchaser a copy of 527 CMR 30.00 upon sale of the unit. 

(13) After NFPA-54 section 9.24 add the following new sub-sections: 

(a) 9.24.1 Solenoid Valve: Gas engines shall be equipped with an automatic solenoid 
gas valve electrically connected to the ignition circuit of the engine that closes whenever 
the engine stops running. 

(b) 9.24.2 Flexible connectors: 

1 . Engines operating at gas pressure of 1 5 P.S .I.G. or less connected to generator of 
1 5 KW or less may use a flexible neoprene hose bearing the manufacturer's name and 
acceptance for LP. or Natural Gas service. 

2. Engines operating at gas pressures above 1 5 P.S.I.G. connected to generators with 
an output of 15 KW or more shall use a Product-approved flexible connector. 



3/11/05 248 CMR -42 




248 CMR: BOARD OF STATE EXAMINERS 
OF PLUMBERS AND GAS FTTTERS 



5.07: continued 

(c) 9.24.3 Fuel Supply: Fuel lines to gas engines shall be supplied only from hard case 
gas meters. 

(d) 9.24.4 Emergency power generators for life safety purposes shall be installed 
according to the following: 

1. A dedicated fuel line shall be installed for the emergency power generator 
immediately downstream of the meter assembly or shut off valve (if no meter is 
provided). 

2. The fuel line for the emergency power generator and the fuel line for the 
remaining appliances shall have shut off valves installed immediately downstream 
of the meter fit to enable each line to operate independently. 

3. The installation of pressure regulators, if required, shall enable each fuel line to 
operate independently and not adversely affect the gas pressure of the other fuel line. 

4. The fuel line for the emergency power generator shall be labeled at: 

a. the shutoff valve, 

b. on each side of the wall, floor or roof penetration, and 

c. every ten feet with the following: 

WARNING: Emergency Power Generator for Life Safety Systems. Do not shut 
off without the approval of appropriate aiithorities. 

(14) Add a new NFPA-54 section 9.32 as follows: 

Gas-fired Kilns . Gas-fired Kilns shall not be installed until after Special-permission under 
248 CMR 3.00 has been granted by the Board. 

5.08: Modifications to NFPA-54. Chapter 10 

(1) Revise NFPA-54 section 10.5.4.2 by adding a second exception as follows: 

Existing chimneys shall be permitted to have their use continued when a gas conversion 
burner is installed, and shall be equipped with a manually reset device that will automatically 
shut off the gas to the burner in the event of a sustained back-draft. 

(2) Revise 10.8.3 by adding the following additional requirements: 

(a) For all side wall horizontally vented gas fueled equipment installed in every dwelling, 
building or structure used in whole or in part for residential purposes, including those owned 
or operated by the Commonwealth and where the side wall exhaust vent termination is less 
than seven feet above finished grade in the area of the venting, including but not limited to 
decks and porches, the following requirements shall be satisfied: 

1. INSTALLATION OF CARBON MONOXIDE DETECTORS . At the time of 
installation of the side wall horizontal vented gas fueled equipment, the installing 
plumber or gasfitter shall observe that a hard wired carbon monoxide detector with an 
alarm and battery back-up is installed on the floor level where the gas equipment is to be 
installed. In addition, the installing plumber or gasfitter shall observe that a battery 
operated or hard wired carbon monoxide detector with an alarm is installed on each 
additional level of the dweUing, building or structure served by the side wall horizontal 
vented gas fueled equipment. It shall be the responsibility of the property owner to secure 
the services of qualified licensed professionals for the installation of hard wired carbon 
monoxide detectors 

a. In the event that the side wall horizontally vented gas fueled equipment is 
installed in. a crawl space or an attic, the hard wired carbon monoxide detector with 
alarm and battery back-up may be installed on the next adjacent floor level. 

b. In the event that the requirements of this subdivision can not be met at the time 
of completion of installation, the owner shall have a period of 30 days to comply with 
the above requirements; provided, however, that during said 30 day period, a battery 
operated carbon monoxide detector with an alarm shall be installed. 

2. APPROVED CARBON MONOXIDE DETECTORS . Each carbon monoxide 
detector as required in accordance with the above provisions shall comply with NFPA 
720 and be ANSI/UL 2034 listed and L\S certified. 

12/30/05 248 CMR -43 



248 CMR: BOARD OF STATE EXAMINERS 
OF PLUMBERS AND GAS FITTERS 



5.08: continued 

3. SIGNAGE . A metal or plastic identification plate shall be permanently mounted to 
the exterior of the building at a minimum height of eight feet above grade directly in line 
with the exhaust vent terminal for the horizontally vented gas fueled heating appliance 
or equipment. The sign shall read, in print size no less than Vz inch in size, "GAS VENT 
DIRECTLY BELOW. KEEP CLEAR OF ALL OBSTRUCTIONS". 

4. INSPECTION . The state or local gas inspector of the side wall horizontally vented 
gas fueled equipment shall not approve the installation unless, upon inspection, the 
inspector observes carbon monoxide detectors and signage installed in accordance with 
the provisions of 248 CMR 5.08(2)(a)l through 4. 

(b) EXEMPTIONS : The following equipment is exempt from 248 CMR 5. 08(2)(a)l. 
through 4.: 

1. The equipment listed in Chapter 10 entitled "Equipment Not Required To Be 
Vented" in the most current edition of NFPA 54 as adopted by the Board; and 

2. Product Approved side wall horizontally vented gas fueled equipment installed in a 
room or structure separate from the dwelling, building or structure used in whole or in 
part for residential purposes. 

(c) MANUFACTURER REOUIREMENTS - GAS EOUIPMENT VENTING SYSTEM 
PROVIDED . When the manufacturer of Product Approved side wall horizontally vented gas 
equipment provides a venting system design or venting system components with the 
equipment, the instructions provided by the manufacturer for installation of the equipment 
and the venting system shall include: 

1 . Detailed instructions for the installation of the venting system design or the venting 
system components; and 

2. A complete parts list for the venting system design or venting system. 

(d) MANUFACTURER REOUIREMENTS - GAS EOUIPMENT VENTING SYSTEM 
NOT PROVIDED . When the manufacturer of a Product Approved side wall horizontally 
veiited gas fueled equipment does not provide the parts for venting the flue gases, but 
identifies "special venting systems", the following requirements shall be satisfied by the 
manufacturer: 

1. The referenced "special venting system" instructions shall be included with the 
appliance or equipment installation instructions; and 

2. The "special venting systems" shall be Product Approved by the Board, and the 
instructions for that system shall include a parts list and detailed installation instructions. . 

(e) A copy of all installation instructions for all Product Approved side wall horizontally 
vented gas fueled equipment, all venting instructions, all parts lists for venting instructions, 
and/or all venting design instructions shall remain with the appliance or equipment at the 
completion of the installation. 

(3) After NFPA-54 section 10.10.4.2 add a new section 10.10.4.3 as follows: 

When more than four gas appliances are to be vented through a common gas vent or common 
horizontal vent manifold, a plan of the proposed vent installation shall be submitted to the- 
Inspector and the serving gas supplier for review and approval. 

5.09: Modifications to NFPA-54. Chapter 1 1 

After NFPA-54 section 11.7 add new 11.8 in sections as follows: 

Procedures for Initial Operation of Industrial Gas Equipment as defined in 248 CMR 7.01: 

(1) 11.8.1 General: 

(a) The following procedures are to be followed in connection with initial operation of 
gas equipment, necessary adjustments, development of operating instructions, instruction 
of the operator in the safe and satisfactory use of the equipment and required acceptance 
tests. 

(b) An authorized representative of the gas equipment manufacturer shall be used to 
start, light, and adjust burners, mixers, flames, blowers, temperature controls and safety 
devices. 



12/30/05 248 CMR -44 



248 CMR: BOARD OF STATE EXAMINERS 
OF PLUMBERS AND GAS FITTERS 



5.09: continued 



(2) 1 1.8.2 New Gas Equipment Procedures: 

(a) Before initial start, it shall be determined by physical check that all protective 
devices are connected and operative, the installation is in all respects capable of safe 
operation, the equipment has been purged in accordance with manufacturer's instructions, 
and that all concerned persons have been notified. 

(b) Initial Start-up and Final Adjustments. An authorized representative of the gas 
equipment manufacturer shall perform the initial start up, final adjusting and testing of 
the burner and controls in the presence of the Inspector and a gas company 
representative. 

(c) Operation: Installed protective devices shall be tested under operating conditions as 
promptly as possible to determine that they are functioning properly. Other instruments 
and controls should also be tested in the same manner. Gas equipment shall be shut 
doWn immediately if any defect is noted during initial start-up or operation. Defects 
shall be corrected before the equipment is again started. In shutting down equipment, 
manufacturers instructions and applicable safety requirements shall be followed. 

(d) Adjustments: Adjustments to burners, pilots, ignition devices, safety devices, and 
controls shall be made in accordance with manufacturer's instructions and applicable 
safety requirements. 

(3) 11.8.3 Operating Instructions: Operating instructions, as supplied by equipment 
manufacturers, shall be assembled and integrated into a system, delivered to the user, and the 
operator instructed in their use in order to assure safe and satisfactory operation of the 
equipment. 

(4) 11.8.4 Acceptance Tests: Acceptance tests shall be conducted if necessary to establish 
compliance with applicable codes or requirements of the Inspector. 



REGULATORY AUTHORITY 

248 CMR 5.00: M.G.L. c. 1 12, § 61; M.G.L. c. 142, §§ 13 and 21. 



12/30/05 248 CMR -44.1 



248 CMR: BOARD OF STATE EXAMINERS 
OF PLUMBERS AND GAS FITTERS 



NON-TEXT PAGE 



12/30/05 248 CMR - 44.2 



248 CMR: BOARD OF STATE EXAMINERS 
OF PLUMBERS AND GAS FITTERS 




(248 CMR 6.00: RESERVED) 



3/11/05 248 CMR -45 



248 CMR: BOARD OF STATE EXAAllNERS 
OF PLUMBERS AND GAS FITTERS 



NON-TEXT PAGE 



3/1 1/05 248 CMR - 46 




248 CMR: BOARD OF STATE EXAMINERS 
OF PLUMBERS AND GAS FITTERS 



248 CMR 7:00: MASSACHUSETTS CODE FOR GAS UTILIZATION EQUIPMENT IN LARGE 

BOILERS 

Section 



7.01 
7.02 
7.03 
7.04 
7.05 



Scope and Purpose 

Definitions 

General Provisions 

Installation of Burners and Controls 

Initial Start-up and Final Adjustments 




7.01: Scope and Purpose 

248 CMR 7.00 covers gas utilization equipment in commercial and industrial boilers having 
inputs over 400,000 BTU per hour per combustion chamber except: gas designed atmospheric 
multiple burner type boilers and water-tube boilers having outputs of 10,000 pounds of steam 
per hour (approximately 12,500,000 BTU per hour input) or more.* 

7.02: Defmitions 

As used in 248 CMR 7.00: 

Air Shutter . An adjustable device for varying the size of the air inlet or inlets regulating primary 
or secondary air. 

Boiler, High-pressure . A boiler furnishing steam at pressure in excess of 15 psi or hot water at 
temperatures in excess of 250°F or at pressures in excess of 160 psi. 

Boiler. Low-pressure Hot Water and Low-pressure Steam . A boiler furnishing hot water at 
pressures not exceeding 160 P.S.I.G. and at temperatures not more than 250°F or steam at 
pressures not more than 15 P.S.I.G. 

Breeching . (See Chimney Connector.) 

Burner . A device for the final conveyance of the gas, or a mixture of gas and air to the 
combustion zone. 

(a) Injection (Bunsen) Type Burner . A burner employing the energy of a iet of gas to inject 
air for combustion into the burner and mix it with the gas. 

(b) Atmospheric Injection Type Burner . A burner in which the air at atmospheric pressure 
is injected into the burner by a jet of gas. 

(c) Luminous or Yellow Flame Burner . A burner in which secondary air only is depended 
on for combustion of the gas. 

(d) Power Burner . A burner in which either gas or air or both are supplied at pressures, 
exceeding, for gas, the line pressure and, for air, atmospheric pressure; this added pressure 
being applied at the burner. A burner for which air for combustion is supplied by a fan ahead 
of the appliance is commonly designated as a forced draft burner. 

(e) Premixing Burner . A power burner in which all or nearly all of the air for combustion 
is mixed with the gas as primary air. 

(f) Induced Draft Burner . A burner which depends on the draft induced by a fan beyond the 
appliance for its proper operation. 

(g) Pressure Burner . A biuner which is supplied with an air-gas mixture under pressure 
(usually from 0.5 to 14.0 inches of water and occasionally higher). 

Burner Head . That portion of a burner beyond the outlet end of the mixer tube which contains 
the ports. 

Burner, Automatica:Ilv Lighted . One where fuel to the main burner is normally turned on and 
ignited automatically. 

* See NFPA No. 8501-1992 and NFPA No. 85C-1991 for Water - Tube Boilers having outputs 

of 10,000 pounds of steam or more. 

3/1 1/05 248 CMR - 47 



2002 Edition 



i 



m 



NFPA^ 



NFPA 54-2002 



Comprehensive 

Consensus 

Codes- 



American Gas Association 

An American National Standard 
ANSI Z223.1-2002 



IMPORTANT NOTICE ABOUT THIS DOCUMENT 

The AGA and the NFPA codes and standards, of which the document contained herein is one, are developed through 
consensus standards development processes approved by the American National Standards Institute. These processes 
bring together volunteers representing varied viewpoints and interests to achieve consensus on fire and other safety is- 
sues. While the AGA and the NFPA administer the processes and establish rules to promote fairness in the development 
of consensus, they do not independently test, evaluate, or verify the accuracy of any information or the soundness of 
any judgments contained in their codes and standards. 

The AGA and the NFPA disclaim liability for any personal injury, property or other damages of any nature whatso- 
ever, whether special, indirect, consequential or compensatory, directly or indirectly resulting from the publication, use 
of, or reliance on this document. The AGA and the NFPA also make no guarantee or warranty as to the accuracy or 
completeness of any information pubhshed herein. 

In issuing and making this document available, the AGA and the NFPA are not undertaking to render professional or 
other services for or on behalf of any person or entity. Nor are the AGA and the NFPA undertaking to perform any duty 
owed by any person or entity to someone else. Anyone using this document should rely on his or her own independent 
judgment or, as appropriate, seek the advice of a competent professional in determining the exercise of reasonable care 
in any given circumstances. 

The AGA and the NFPA have no power, nor do they undertake, to police or enforce compliance with the contents of this 
document. Nor do the AGA and the NFPA list, certify, test, or inspect products, designs, or installations for compliance 
with this document. Any certification or other statement of compliance with the requirements of this document shall not be 
attributable to the AGA and the NFPA and is solely the responsibility of the certifier or maker of the statement. 
See inside back cover for additional important notices and information. 

Eighth Edition— 2002 
Printed in U.S.A 

Copyright © 2002 by the American Gas Association and the National Fire Protection Association. Permission is 
granted to republish in full the material herein in laws, ordinances, regulations, administrative orders, or similar docu- 
ments issued by public authorities. All others desiring permission to reproduce this material in whole or in part shall 
consult the American Gas Association, Codes and Standards, 400 N. Capitol Street, N.W., Washington, DC 20001 and 
the National Fire Protection Association, 1 Batterymarch Park, P.O. Box 9101, Quincy, MA 02269-9101. (For further 
explanation, see the Policy Concerning the Adoption, Printing, and PubUcation of NFPA Documents, which is available 
upon request from the NFPA.) 

04 03 02 1 1 10 9 8 7 6 5 4 3 2 



8/02 



In recognition of those who suffered 

from the tragedies of September 11, 2001, 

this document is dedicated to all who 

have given their lives in an effort 

to make this world a safer place. 



ANSI Z223. 1-1 54-1 



Copyright © 2002, by the National Fire Protection Association and the 
American Gas Association, All Rights Reserved 

NFPA 54-2002 

ANSI Z223. 1-2002 

National Fuel Gas Code 

2002 Edition 

This 2002 edition incorporates changes to the 1999 edition. It was adopted by the National 
Fire Protection Association (NFPA) on July 19, 2002 and was approved by the American 
National Standards Institute, Inc. (ANSI) on August 1, 2002. The ANSI designation is Z223.1- 
2002. The NFPA designation is NFPA 54-2002. 

Changes other than editorial, including dimensional abbreviations, from the 1999 edition 
are denoted by a vertical line in the margin. 

Origin and Development 

This code ofifers general criteria for the installation and operation of gas piping and gas 
equipment on consumers' premises. It is the cumulative result of years of experience of many 
individuals and many organizations acquainted with the installation of gas piping and equip- 
ment designed for utilization of gaseous fuels. It is intended to promote public safet}' by 
providing requirements for the safe and satisfactory utilization of gas. 

Changes in this code can become necessary from time to time. When any revision is 
deemed advisable, recommendations should be forwarded to the Secretary, Accredited Stan- 
dards Committee Z223, 400 N. Capitol St. NW, Washington, DC 20001, and the Secretary, 
Standards Council, National Fire Protection Association, 1 Batterymarch Park, P.O. Box 9101, 
Quincy, MA 02269-9101. 

In October 1967, representatives of the American Gas Association, the American Society of 
Mechanical Engineers, and the National Fire Protection Association met as a Conference 
Group on Piping and Installation Standards to consider the development of a single National 
Fuel Gas Code. This conference was the result of the expressed need within the gas industry, 
among public safety authorities, insurance groups, architects, designers, and builders, for one 
code that would cover all facets of fuel gas piping and appliance installation downstream from 
meter set assemblies or other components comprising the gas service entrance to the con- 
sumer premises. 

At a January 1968 meeting, the conference group developed the objectives and scope of a 
proposed National Standards Committee. The group envisioned the combining of the follow- 
ing standards into a single National Fuel Gas Code: 

(1) American National Standard Installation of Gas Appliances and Gas Piping, ANSI Z21.30 
(NFPA 54) 

( 2 ) Installation of Gas Piping and Gas Equipment on Industrial Premises and Certain Other Premises, 
ANSIZ83.1 (NFPA54A) 

(3) Fuel Gas Piping, ASME B31 .2 

The proposed scope at that time limited coverage of piping systems to 60 psi (414 kPa). 
The National Standards Committee agreed to rehnquish Z21.30 (NFPA 54), Z83.1 
(NFPA 54A), and applicable portions of ASME B31.2 covering piping systems up to and 
including 60 psi (414 kPa) to a new National Fuel Gas Code Committee, cosponsored by the 
three associations. 

On August 13, 1971, the American National Standards Institute approved the scope of 
activities and the formation of the National Standards Committee on National Fuel Gas Code, 
Z223. 

To establish a National Fuel Gas Code to satisfy the immediate needs of the gas industry, at its 
December 6, 1972, organizational meeting the Z223 Committee combined NFPA 54-1969, 
Z21. 30-1969, and Z83. 1-1972 vrith only those editorial revisions necessary to reflect the scope 
of the new code. Further revisions of the code would be necessary to incorporate pertinent 
coverage for fuel gas piping from ASME B31. 2-1968. 



54-2 NATIONAL FUEL GAS CODE ANSI Z223. 1-2 

The first edition of the code was issued in 1974. The American Gas Association and the National Fire Protection 
Association have continued cosponsorship of the code following the first edition. 

The second edition of the code, incorporating pertinent portions of B31.2, was issued in 1980. The third, fourth, 
fifth, sixth, and seventh editions were issued in 1984, 1988, 1992, 1996, and 1999, respectively. The scope of the code 
was expanded in 1988 to include piping systems up to and including 125 psi (862 kPa). 

The 2002 edition revises the requirements to determine if the indoor air volume is sufficient for combustion and 
ventilation air needs of appliances installed within the space. A new method is added that allows the use of actual or 
calculated building air exchange rate in determining if there is adequate indoor air volume based on the combustion 
air needs for fan-assisted combustion appliances and other appliance types. 

Codifying the longest length method and adding a new branch length method result in the revision of the require- 
ments for gas pipe sizing. The pipe sizing tables have been recalculated and pipe sizing equations have been revised. 

Prior editions of this document have been translated into languages other than English, including Spanish. 



2002 Edition 



ANSI Z223. 1-3 



COMMITTEE PERSONNEL 



54-3 



Technical Committee on National Fuel Gas Code 

Mike R. Gorham, Chair 

Northwest LP-Gas Co., MN [MI/P] 

Rep. National Propane Gas Association 



Paul W. Cabot, Administrative Secretary 
American Gas Association, Washington, DC (Nonvoting) 



Paul E. Beach, Emerson Electric Company, OH [M/M] 

Rep. Gas Appliance Manufacturers Association, Inc. 
John Beck, Pacific Gas and Electric Company, CA [U] 

Rep. American Gas Association 
James P. Brewer, Magic Sweep Corp., VA [IM/S] 

Rep. National Chimney Sweep Guild 
Duane W. Brown, Ranger Insurance Company, TX [I/I] 
William H. Bruno, DBA Bruno's Enterprises, MO [I/S] 
Thomas E. Buchal, Intertek Testing Services, MN [RT/S] 
David T. Bumell, Main Propane and National Gas Board, 
ME[E] 

Byron Caffey, Railroad Commission of Texas, TX [E/G] 
AUenJ. CaUahan, CSA America, OH [RT/S] 
Sidney Cavanaugh, United Association of 
Journeymen/Apprentices of Plumbing /Pipe Fitting 
Industry of the U.S. and Canada, CA [L/G] 
Robert Cave, f American Pubhc Gas Association, VA [ U] 
Sharon Coates, State of Arkansas, AR [E/G] 

Rep. International Fire Marshals Association 
Thomas R. Crane, Crane Engineering and Forensic 
Services, MN [SE/S] 

John P, Doucette, State of Connecticut, CT [E/G] 
Glen Edgar, Selkirk, Inc., OH [M/M] 

Rep. Gas Appliance Manufacturers Association, Inc. 
Alberto Jose Fossa, *MDJ Consul tores Associadoes Ltda, 
Brasil [SE] 

Rep. NFPA Latin American Secdon 
Gregg Gress, f Building Officials and Code 
Administrators International, Inc., IL [G] 
WUbur Haag Jr., A.O. Smith Water Products Company, SC 
[M/M] 

Rep. Gas Appliance Manufacturers Association, Inc. 
Steen Hagensen, Exhausto Inc., GA [M/M] 
John M. Halliwill, International Association of Plumbing 
& Mechanical Officials, CA [E/G] 
Leonard Herman, f New Jersey Builder, NJ [E] 

Rep. National Association of Home Builders 



Patricio Himes Radke, Sistemas de Energia, Mexico 
[U/P] 

Rep. Asociacion Mexicana Distribuidores de Gas 
Daryl L. Hosier, Southern California Gas Company, CA 
[IM/U] 
Russel Iwan, Metropolitan Utilities District, NE [U/U] 

Rep. American Gas Association 
Theodore C. Lemoff, f National Fire Protection 
Association, MA [S] 

Brian C. Olson, National Park Service, CO [U/G] 
Kenneth P. Padgett, Piedmont Natural Gas 
Company/ICC, SC [E/U] 

Rep. International Code Council, Inc. /Southern 

Building Code Congress International 
WmdeU E Peters, AGL Resources, GA [IM/U] 

Rep. American Gas Association 
Dale Powell, Copper Development Association, PA 
[M/M] 

Daniel Restelli, f Underwriters Laboratories Inc., IL 
[RT/S] 

Robert E. Rhead, Kemper Insurance Companies, IL [I/I] 
David W. Rock, City of Pordand, OR [E/G] 

Rep. Oregon Mechanical Officials Association 
Isaac Sai^unam, Maytag Corporation, lA [M/U] 

Rep. Association of Home Appliance Manufacturers 
Gregory L. Seitz, New Jersey Natural Gas Company, NJ 
[IM/U] 

Rep. American Gas Association 
Gary Strebe, International Comfort Products Corp., TN 
[M] 

Rep. Gas Appliance Manufacturers Associadon 
Hall "\^i^, t Carrier Corporation, IN [M] 

Rep. Gas Appliance Manufacturers Association 
John W. Wasson, f City of Greenville, SC [G] 
Richard E. White, Richard E. White & Associates, IN 
[U/E] 

Rep. Nadonal Association of 

Plumbing-Heating-Cooling Contractors 



Alternates 



Hari Ramanathan, International Associadon of Plumbing 
& Mechanical Officials, CA [E/G] 

(Alt. to J. M. Halliwill) 
Michael Snyder, * ServiceAir, MD [U] 

(Alt. to R. E. White) 
Bruce J. Swiecicki, National Propane Gas Association, IL 
[IM/P] 

(Alt. to M. R. Gorham) 



Ed Angelone, f KeySpan Energy, NY [U] 

(Alt. forAGA) 
John R. Batdes, f Southern Building Code Congress Inc., 
AL[S] 

(Alt. for SBCCI) 
Gregory S. Koll, Metropolitan Utilides District, NE [U] 

(Alt. to R. Iwan) 
Blaine R. Lanning, CSAAmerica, OH [RT/S] 

(Alt. to A. J. Callahan) 

Theodore C. Lemoff,* NFPA Staff Liaison 

*NFPA 54 Comnriittee only. tZ223 Committee only. 

Committee Scope: This Committee shall have primary responsibility for documents on safety code for gas 
piping systems on consumers' premises and the installation of gas utilization equipment and accessories for 
use with fuel gases such as natural gas, manufactured gas, liquefied petroleum gas in the vapor phase, 
liquefied petroleum gas-air mixtures, or mixtures of these gases, including: (a) The design, fabrication, 
installation, testing, operation, and maintenance of gas piping systems from the point of delivery to the 
connections with each gas utilization device. Piping systems covered by this code are limited to a maximum 



2002 Edition 



54-4 NATIONAL FUEL GAS CODE ANSI Z223. 1-4 

operating pressure of 125 psig. For purposes of this code, the point of delivery is defined as the outlet of the 
meter set assembly, or the outlet of the service regulator or service shutoff valve where no meter is provided, 
(b) The installation of gas utilization equipment, related accessories, and their ventilation and venting 
systems. 

This list represents the membership at the time the Committee was balloted on the final text of this edition. Since that time, 
changes in the membership may have occurred. A key to classifications is found at the back of the document. 

NOTE: Membership on a committee shall not in and of itself constitute an endorsement of the Association or 
any document developed by the committee on which the member serves. 

The National Fuel Gas Code Committee is a committee functioning jointly under American National Stan- 
dards Institute Accredited Standard Committee Z223 procedures and the National Fire Protection Associa- 
tion and, accordingly, the National Fuel Gas Ccxie bears two designations, ANSI Z223.1 and NFPA54. In the 
ANSI context, the code is prepared by the Accredited Standards Committee on National Fuel Gas Code, 
Z223, sponsored by the American Gas Association (Administrative Secretariat). In the NFPA context the 
committee is an NFPA Technical Committee submitted to ANSI under the NFPA audited designation. 



2002 Edition 



ANSI Z223. 1-5 



CONTENTS 



54^5 



Chapter 1 Administration 54— 

1.1 Scope 54— 

1.2 Purpose 54r- 

1.3 Retroactivity 54- 

1.4 Equivalency 54— 

1.5 Enforcement 54- 



Contents 

7 
7 
7 
7 
7 



6.13 Electrical Bonding and Grounding 54— 25 

6.14 Electrical Circuits 54r- 25 

6.15 Electrical Connections 54— 25 



Chapter 2 Referenced Publications (Reserved) 54— 8 

Chapters Definitions 54^ 8 

3.1 General 54- 8 

3.2 (Reserved) 54- 8 

3.3 General Definitions 54- 8 

Chapter 4 General 54- 15 

4.1 Qualified Agency 54- 15 

4.2 Interruption of Service 54— 15 

4.3 Prevention of Accidental Ignition 54— 15 

Chapter 5 Gas Piping System Design, Materials, 

and Components 54— 16 

5.1 PipingPlan 54- 16 

5.2 Provision for Location of Point of 

Delivery 54- 16 

5.3 Interconnections Between Gas Piping 

Systems 54— 16 

5.4 Sizing of Gas Piping Systems 54^ 16 

5.5 Piping System Operating Pressure 
Limitations 54— 17 

5.6 Acceptable Piping Materials and 

Joining Methods 54- 17 

5.7 GasMeters 54- 19 

5.8 Gas Pressure Regulators 54— 19 

5.9 Overpressure Protection Devices 54— 20 

5.10 Back Pressure Protection 54- 21 

5.11 Low-Pressure Protection 54— 21 

5.12 ShutoffValves 54- 21 

5.13 Expansion and Flexibility 54— 21 

Chapter 6 Gas Piping Installation 54— 21 

6.1 Piping Underground 54— 21 

6.2 Installation of Piping 54- 22 

6.3 Concealed Piping in Buildings 54— 22 

6.4 Piping in Vertical Chases 54— 23 

6.5 GasPipe Turns 54- 23 

6.6 Drips and Sediment Traps 54- 23 

6.7 Outlets 54- 23 

6.8 Branch Pipe Connection 54- 24 

6.9 Manual Gas Shutofif Valves 54- 24 

6.10 Prohibited Devices 54- 24 

6.11 Systems Containing Gas-Air Mixtures 

Outside the Flammable Range 54- 24 

6.12 Systems Containing Flammable 

Gas-Air Mixtures 54- 24 



Chapter 7 Inspection, Testing, and Purging 54^ 25 

7. 1 Pressure Testing and Inspection 54— 25 

7.2 System and Equipment Leakage Test 54- 26 

7.3 Purging 54-26 

Chapters Equipment Installation 54— 27 

8.1 General 54- 27 

8.2 Accessibility and Clearance 54- 29 

8.3 Air for Combustion and Ventilation 54— 29 

8.4 Equipment on Roofs 54^ 31 

8.5 Equipment Connections to Building 

Piping 54- 31 

8.6 Electrical 54- 32 

8.7 Room Temperature Thermostats 54^ 32 

Chapter 9 Installation of Specific Equipment 54^ 33 

9.1 General 54- 33 

9.2 Air-Conditioning Equipment 
(Gas-Fired Air Conditioners and 
HeatPumps) 54- 33 

9.3 Central Heating Boilers and Furnaces .... 54— 35 

9.4 Clothes Dryers 54- 37 

9.5 Conversion Burners 54— 37 

9.6 Decorative Appliances for Installation 

in Vented Fireplaces 54^ 37 

9.7 Gas Fireplaces, Vented 54- 38 

9.8 Non-Recirculating Direct Gas-Fired 

Industrial Air Heaters 54— 38 

9.9 Recirculating Direct Gas-Fired 

Industrial Air Heaters 54— 39 

9.10 DuctFurnaces 54- 39 

9.11 Floor Furnaces 54— 40 

9.12 Food Service Equipment, 

Floor-Mounted 54— 41 

9.13 Food Service Equipment Counter 

Appliances 54— 41 

9.14 Hot Plates and Laundry Stoves 54- 42 

9.15 Household Cooking Appliances 54— 42 

9.16 Illuminating Appliances 54— 42 

9.17 Incinerators, Commercial-Industrial 54^ 43 

9.18 Infrared Heaters 54- 43 

9.19 Open-Top Broiler Units 54- 43 

9.20 Outdoor Cooking Appliances 54— 44 

9.21 Pool Heaters 54- 44 

9.22 Refrigerators 54- 44 

9.23 RoomHeaters 54- 44 

9.24 Stationary Gas Engines 54- 45 

9.25 Gas-Fired Toilets 54- 45 

9.26 UnitHeaters 54- 45 

9.27 Wall Furnaces 54- 45 



2002 Edition 



54-6 



NATIONAL FUEL GAS CODE 



ANSI Z223. 1-6 



9.28 Water Heaters 54-46 

9.29 Compressed Natural Gas (CNG) 

Vehicular Fuel Systems 54- 46 

9.30 Appliances for Installation in 

Manufactured Housing 54— 46 

9.31 Fuel Cell Power Plants 54- 46 

Chapter 10 Venting of Equipment 54— 47 

10.1 General 54- 47 

10.2 Specification for Venting 54— 47 

10.3 Design and Construction 54— 47 

10.4 Type of Venting System to Be Used 54- 48 

10.5 Masonry, Metal, and Factory-Built 

Chimneys 54— 48 

10.6 Gas Vents 54- 50 

10.7 Single-Wall Metal Pipe 54- 51 

10.8 Through the Wall Vent Termination 54— 53 

10.9 Condensation Drain 54— 53 

10.10 Vent Connectors for Category I Gas 
Utilization Equipment 54— 53 

10.11 Vent Connectors for Category II, 
Category III, and Category IV Gas 

Utilization Equipment 54r- 55 

10.12 Draft Hoods and Draft Controls 54- 55 

10.13 Manually Operated Dampers 54- 55 

10.14 Automatically Operated Vent Dampers .. . 54- 55 

10.15 Obstructions 54- 56 

Chapter 11 Procedures to Be Followed to Place 

Equipment in Operation 54— 56 

11.1 Adjusting the Burner Input 54— 56 

11.2 Primary Air Adjustment 54r- 57 

11.3 Safety Shutoff Devices 54- 57 

11.4 Automatic Ignidon 54- 57 

11.5 Protective Devices 54— 57 

11.6 Checking the Draft 54- 57 

11.7 Operating Instructions 54— 57 

Chapter 12 Pipe Sizing 54- 57 

12.1 Pipe Sizing Methods 54- 57 

12.2 Tables for Sizing Gas Piping Systems 54— 57 

12.3 Sizing Equations 54^ 57 



Chapter 13 Sizing of Category I Venting 

Systems 54- 89 

13.1 Additional Requirements to Single 
Appliance Vent Table 13.1 

Through Table 13.5 54- 89 

13.2 Additional Requirements to Multiple 
Appliance Vent Table 13.6 
Through Table 13.13(a) and Table 

13.13(b) 54- 96 

Chapter 14 Referenced Publications 54—1 08 

14.1 General 54-108 

Annex A Explanatory Material 54r-108 

Aimex B Coordination of Gas Utilization 
Equipment Design, Construction, 
and Maintenance 54—115 

Annex C Sizing and Capacities of Gas Piping 54-1 1 6 

Annex D Suggested Method of Checking for 

Leakage 54-125 

Annex E Suggested Emergency Procedure for 

GasLeaks 54-125 

Annex F Flow of Gas Through Fixed Orifices 54— 1 26 

Annex G Sizing of Venting Systems Serving 
Appliances Equipped with Draft 
Hoods, Category I AppUances, and 
Appliances Listed for Use with 
TypeBVents 54-131 

Annex H Recommended Procedure for Safety 
Inspection of an Existing 
Appliance Installation 54—1 38 

Annex I Indoor Combustion Air Calculation 

Examples 54r-l 39 

Annex J Example of Combination of Indoor 
and Outdoor Combustion and 
Ventilation Opening Design 54-141 

AimexK Other Useful Definitions 54—141 

Annex L Informational References 54—143 

Index 54-146 



2002 Edition 



ANSI Z223. 1-7 



ADMINISTRATION 



54^7 



NFPA 54-2002 

ANSI Z223. 1-2002 

National Fuel Gas Code 

2002 Edition 

NOTICE: An asterisk (*) following the number or letter desig- 
nating a paragraph indicates that explanatory material on the 
paragraph can be found in Annex A. 

Changes other than editorial are indicated by a vertical 
rule beside the paragraph, table, or figure in which the 
change occurred. These rules are included as an aid to the 
user in identifying changes from the previous edition. Where 
one or more complete paragraphs have been deleted, the de- 
letion is indicated by a bullet between the paragraphs that 
remain. 

A reference in brackets [ ] following a section or paragraph 
indicates material that has been extracted from another NFPA 
document. As an aid to the user. Annex L lists the complete 
title and edition of the source documents for both mandatory 
and nonmandatory extracts. Editorial changes to extracted 
material consist of revising references to an appropriate divi- 
sion in this document or the inclusion of the document num- 
ber with the division number when the reference is to the 
original document. Requests for interpretations or revisions 
of extracted text shall be sent to the appropriate technical 
committee. 

Information on referenced publications can be found in 
Chapter 2 and Annex L. 

AJl pressures used in this code are gauge pressure unless 
otherwise indicated. 



Chapter 1 Administration 

1.1 Scope. 

1.1.1 Applicability. 

1.1.1.1 This code is a safety code that shall apply to the instal- 
lation of fuel gas piping systems, fuel gas urilization equip- 
ment, and related accessories as shown in 1.1.1.1(A) through 
1.1.1.1(D). 

(A) Coverage of piping systems shall extend from the point of 
delivery to the connections v^th each gas utilization device. 
For other than undiluted liquefied petroleum gas systems, the 
point of delivery shall be considered the outlet of the service 
meter assembly or the outlet of the service regulator or service 
shutoff valve where no meter is provided. For undiluted lique- 
fied petroleum gas systems, the point of delivery shall be con- 
sidered the outlet of the final pressure regulator, exclusive of 
line gas regulators, in the system. 

(B) The maximum operating pressure shall be 125 psi 

(862 kPa). 

Exception No. 1: Piping systems for gas-air mixtures within the flam- 
mable range are limited to a maximum pressure of 10 psi (69 kPa). 

Exception No. 2: LP-Gas piping sy sterns are limited to 20 psi (140 kPa), 
except as provided in 5.5.2. 

(C) Piping systems requirements shall include design, mate- 
rials, components, fabrication, assembly, installation, testing, 
inspection, operation, and maintenance. 



(D) Requirements for gas utilization equipment and related 
accessories shall include installation, combustion, and ventila- 
tion air and venting. 

1.1.1.2 This code shall not apply to the following items (ref- 
erence standards for some of which appear in Annex L): 

(1) Portable LP-Gas equipment of all types that are not con- 
nected to a fixed fuel piping system 

(2) Installation of farm equipment such as brooders, dehy- 
drators, dryers, and irrigation equipment 

(3) Raw material (feedstock) applications except for piping 
to special atmosphere generators 

(4) Oxygen-fuel gas cutting and welding systems 

(5) Industrial gas applications using such gases as acetylene 
and acetylenic compounds, hydrogen, ammonia, carbon 
monoxide, oxygen, and nitrogen 

(6) Petroleum refineries, pipeline compressor or pumping 
stations, loading terminals, compounding plants, refin- 
ery tank farms, and natural gas processing plants 

(7) Large integrated chemical plants or portions of such 
plants where flammable or combustible liquids or gases 
are produced by chemical reactions or used in chemical 
reactions 

(8) LP-Gas installations at utility gas plants 

(9) Liquefied natural gas (LNG) installations 

(10) Fuel gas piping in power and atomic energy plants 

(11) Proprietary items of equipment, apparatus, or instru- 
ments such as gas generating sets, compressors, and 
calorimeters 

(12) LP-Gas equipment for vaporization, gas mixing, and gas 
manufacturing 

(13) LP-Gas piping for buildings under construction or reno- 
vations that is not to become part of the permanent 
building piping system — that is, temporary fixed piping 
for building heat 

(14) Installation of LP-Gas systems for railroad switch heating 

(15) Installation of LP-Gas and compressed natural gas sys- 
tems on vehicles 

(16) Gas piping, meters, gas pressure regulators, and other 
appurtenances used by the serving gas supplier in distri- 
bution of gas, other than undiluted LP-Gas 

(17) Building design and construction, except as specified 
herein 

(18) Fuel gas systems on recreational vehicles manufactured 
in accordance with NFPA 1192, Standard on Recreational 
Vehicles 

(19) Fuel gas systems using hydrogen as a fuel 

1.1.2 Other Standards. In applying this code, reference shall 
also be made to the manufacturers' instructions and the serv- 
ing gas supplier regulations. 

1.2 Purpose. (Reserved) 

1.3 Retroactivity. Unless otherwise stated, the provisions of 
this code shall not be applied retroactively to existing systems 
that were in compliance with the provisions of the code in 
effect at the time of installation. 

1.4 Equivalency. The provisions of this code are not intended 
to prevent the use of any material, method of construction, or 
installation procedure not specifically prescribed by this code, 
provided any such alternate is acceptable to the authority hav- 
ing jurisdiction (see Section 3.3). The authority having jurisdic- 
tion shall require that sufficient evidence be submitted to sub- 
stantiate any claims made regarding the safety of such 
alternates. 



2002 Edition 



54-8 



NATIONAL FUEL GAS CODE 



ANSI Z223.1-8 



1.5* Enforcement. This code shall be administered and en- 
forced by the authority having jurisdiction designated by the 
governing authority. (See A. 1.5 for sample wording for enabling 
legislation.) 



Chapter 2 Referenced Publications (Reserved) 



Chapter 3 Definitions 

3.1 General. The definitions contained in this chapter shall 
apply to the terms used in this code. Where terms are not 
included, common usage of the terms shall apply. 

3.2 (Reserved) 

3.3 General Definitions. 

3.3.1 Accessible. Having access to but v^^hich first requires 
the removal of a panel, door, or similar covering of the item 
described. 

3.3.2 Accessible, Readily. Having direct access without the 
need of removing or moving any panel, door, or similar cover- 
ing of the item described. 

3.3.3 Agency, Qualified. See Qualified Agency. 

3.3.4 Air, Circulating. Air for cooling, heating, or ventilation 
distributed to habitable spaces. 

3.3.5 Air Conditioner, Gas-Fired. A gas-burning, automati- 
cally operated appliance for supplying cooled and/or dehu- 
midified air or chilled liquid. 

3.3.6 Air Conditioning. The treatment of air so as to control 
simultaneously its temperature, humidity, cleanness, and dis- 
tribution to meet the requirements of a conditioned space. 

3.3.7 Air Shutter. An adjustable device for varying the size of 
the primary air inlet(s). 

3.3.8 Anodeless Riser. An assembly of steel cased plastic pipe 
used to make the transition between plastic piping installed 
underground and metallic piping installed aboveground. 

3.3.9 Appliance. Any device that utilizes gas as a fuel or raw 
material to produce light, heat, power, refrigeration, or air 
conditioning. 

3.3.10 Appliance, Automatically Controlled. Appliance 
equipped with an automatic burner ignition and safety shutofif 
device and other automatic devices. 

3.3.11 Appliance Categorized Vent Diameter /Area. The 

minimum vent area/diameter permissible for Category I ap- 
pliances to maintain a nonpositive vent static pressure when 
tested in accordance vsdth nationally recognized standards. 

3.3.12 Appliance, Fan-Assisted Combustion. An appliance 
equipped with an integral mechanical means to either draw or 
force products of combustion through the combustion cham- 
ber or heat exchanger. 

3.3.13 Appliance, Nonresidential, Low-Heat. A commercial, 
industrial, or institutional appliance needing a chimney ca- 
pable of withstanding a continuous flue gas temperature not 
exceeding 1000°F (538°C). [211:1-5] 

3.3.14 Appliance, Nonresidential, Mediimi-Heat. A commer- 
cial, industrial, or institutional appliance needing a chimney 



capable of withstanding a continuous flue gas temperature 
not exceeding 1800°F (982°C). [211:1-5] 

3.3.15* Approved. Acceptable to the authority having juris- 
diction. 

3.3.16 Atmospheric Pressure. The pressure of the weight of 
air and water vapor on the surface of the earth, approximately 
14.7 pounds per square inch (psia) (101 kPa absolute) at sea 
level. 

3.3.17* Authority Having Jurisdiction (AHJ). The organiza- 
tion, office, or individual responsible for approving equip- 
ment, materials, an installation, or a procedure. 

3.3.18 Automatic Firecheck. A device for stopping the 
progress of a flame front in burner mixture lines (flashback) 
and for automatically shutting off the fuel-air mixture. 

3.3.19 Automatic Gas Shutoff Device. A device constructed 
so that the attainment of a water temperature in a hot water 
supply system in excess of some predetermined limit acts in 
such a way as to cause the gas to the system to be shut ofi". 

3.3.20 Automatic Ignition. Ignition of gas at the burner(s) 
when the gas controlling device is turned on, including reigni- 
tion if the flames on the burner(s) have been extinguished by 
means other than by the closing of the gas controlling device. 

3.3.21 Back Pressure. Pressure against which a fluid is flow- 
ing, resulting from friction in lines, restrictions in pipes or 
valves, pressure in vessel to which fluid is flovsdng, hydrostatic 
head, or other impediment that causes resistance to fluid flow. 

3.3.22 Backfire Preventer. See Safety Blowout. 

3.3.23 Baffle. An object placed in an appliance to change 
the direction of or retard the flow of air, air-gas mixtures, or 
flue gases. 

3.3.24 Barometric Draft Regulator. A balanced damper de- 
vice attached to a chimney, vent connector, breeching, or flue 
gas manifold to control chimney draft. 

3.3.25 Boiler, Hot Water Heating. A boiler in which no steam 
is generated, from which hot water is circulated for heating 
purposes and then returned to the boiler, and that operates at 
water pressures not exceeding 160 psi (1100 kPa) and at water 
temperatures not exceeding 250°F (121°C) at or near the 
boiler outiet. 

3.3.26 Boiler, Hot Water Supply. A boiler, completely filled 
with water, that furnishes hot water to be used externally to 
itself and that operates at water pressures not exceeding 160 psi 
(1100 kPa) and at water temperatures not exceeding 250°F 
(121 °C) at or near the boiler outiet. 

3.3.27 Boiler, Low-Pressure. Aself-contained gas-burning ap- 
pliance for supplying steam or hot water. 

3.3.28 Boiler, Steam Heating. A boiler in which steam is gen- 
erated and that operates at a steam pressure not exceeding 15 psi 
(100 kPa). 

3.3.29 Branch Line. Gas piping that conveys gas from a sup- 
ply line to the appliance. 

3.3.30 Breeching. SeeYent Connector. 

3.3.31 Broiler. A general term including broilers, sala- 
manders, barbecues, and other devices cooking primarily by 
radiated heat, excepting toasters. 



2002 Edition 



ANSI Z223. 1-9 



DEFINITIONS 



54-9 



3.3.32 Btu. Abbreviation for British thermal unit, which is the 
quantity of heat required to raise the temperature of 1 pound of 
water 1 degree Fahrenheit (equivalent to 1055 joules). 

3.3.33 Burner. A device for the final conveyance of gas, or a 
mixture of gas and air, to the combustion zone. 

3.3.34 Burner, Forced-Draft. See Burner, Power. 

3.3.35 Burner, Injection (Bunsen) Type. A burner employing 
the energy of a jet of gas to inject air for combustion into the 
burner and mix it with the gas. 

3.3.36 Burner, Power. A burner in which either gas or air, or 
both, are suppHed at a pressure exceeding, for gas, the Hne 
pressure, and for air, atmospheric pressure; this added pres- 
sure being applied at the burner. A burner for which air for 
combustion is supplied by a fan ahead of the appliance is com- 
monly designated as a forced-draft burner. 

3.3.37 Burner, Power, Fan-Assisted. Aburner that uses either 
induced or forced draft. 

3.3.38 Central Premix System. A system that distributes flam- 
mable gas-air mixtures to two or more remote stations. 

3.3.39 Chimney. One or more passageways, vertical or 
nearly so, for conveying flue or vent gases to the outside atmo- 
sphere. (See also Gas Vent, and Venting System.) 

3.3.40 Chimney, Factory-Built. A chimney composed of 
listed factory-built components assembled in accordance with 
the terms of listing to form the completed chimney. 

3.3.41 Chimney, Masonry. A field-constructed chimney of 
solid masonry units, bricks, stones, listed masonry chimney 
units, or reinforced portland cement concrete, lined with suit- 
able chimney flue liners. 



3.3.42 Chimney, Metal. 

metal. 



A field-constructed chimney of 



3.3.43 Clothes Dryer. A device used to dry wet laundry by 
means of heat derived from the combustion of fuel gases. 

3.3.44 Clothes Dryer, Type 1. Factory-built package, multi- 
ply produced. Primarily used in family living environment. 
May or may not be coin-operated for public use. 

3.3.45 Clothes Dryer, Type 2. Factory-built package, multiply 
produced. Used in business with direct intercourse of the 
function with the public. May or may not be operated by pub- 
lic or hired attendant. May or may not be coin-operated. 

3.3.46 Combustible Material. As pertaining to materials ad- 
jacent to or in contact with heat-producing appliances, vent 
connectors, gas vents, chimneys, steam and hot water pipes, 
and warm air ducts, shall mean materials made of or surfaced 
with wood, compressed paper, plant fibers, or other materials 
that are capable of being ignited and burned. Such material 
shall be considered combustible even though flame-proofed, 
fire-retardant treated, or plastered. 

3.3.47 Combustion. As used herein, the rapid oxidation of 
fuel gases accompanied by the production of heat or heat and 
light. Complete combustion of a fuel is possible only in the 
presence of an adequate supply of oxygen. 

3.3.48 Combustion Chamber. The portion of an appliance 
within which combustion occurs. 

3.3.49 Combustion Products. Constituents resulting from 
the combustion of a fuel with the oxygen of the air, including 
the inert but excluding excess air. 



3.3.50 Common Vent. That portion of a vent or chimney sys- 
tem that conveys products of combustion from more than one 
appliance. 

3.3.51 Common Vent Manifold. A horizontal extension of 
the common vent within the room in which the appliances are 
installed. 

3.3.52 Concealed Gas Piping. Gas piping that, when in place 
in a finished building, would require removal of permanent 
construction to gain access to the piping. 

3.3.53 Condensate (Condensation). The liquid that sepa- 
rates from a gas (including flue gas) due to a reduction in 
temperature or an increase in pressure. 

3.3.54 Consumption. The maximum amount of gas per unit 
of time, usually expressed in cubic feet per hour, or Btu per 
hour, required for the operation of the appliance or appli- 
ances supplied. 

3.3.55 Control Piping. All piping, valves, and fittings used to 
interconnect air, gas, or hydraulically operated control appa- 
ratus or instrument transmitters and receivers. 

3.3.56 Controls. Devices designed to regulate the gas, air, 
water, or electrical supply to a gas appliance. These may be 
manual or automatic. 

3.3.57 Convenience Outlet, Gas. A permanently mounted, 
hand-operated device providing a means for connecting and 
disconnecting an appliance or an appliance connector to the 
gas supply piping. The device includes an integral, manually 
operated gas valve with a nondisplaceable valve member so 
that disconnection can be accomplished only when the manu- 
ally operated gas valve is in the closed position. 

3.3.58 Conversion Burner, Gas. A unit consisting of a burner 
and its controls utiHzing gaseous fuel for installation in an 
appliance originally utilizing another fuel. 

3.3.59 Counter Appliances, Gas. See Food Service Equip- 
ment, Gas Counter Appliance. 

3.3.60 Cubic Foot (ft^) of Gas. The amount of gas that 
would occupy 1 ft^ (0.03 m^) when at a temperature of 60°F 
(16°C), saturated with water vapor and under a pressure 
equivalent to that of 30 in. w.c. (7.5 kPa). 

3.3.61 Decorative Appliance for Installation in a Vented Fire- 
place. A self-contained, freestanding, fuel-gas burning appli- 
ance designed for installation only in a vented fireplace and 
whose primary function lies in the aesthetic effect of the 
flame. 

3.3.62 Deep Fat Fryer. See Food Service Equipment, Gas 
Deep Fat Fryer. 

3.3.63 Design Certification. The process by which a product 
is evaluated and tested by an independent laboratory to affirm 
that the product design complies with specific requirements. 

3.3.64 Design Pressure. The maximum operating pressure 
permitted by this code, as determined by the design proce- 
dures applicable to the materials involved. 

3.3.65 Dilution Air. Air that enters a draft hood or draft regu- 
lator and mixes with the flue gases. 

3.3.66 Direct Gas-Fired Industrial Air Heater. A heater in 
which all of the products of combustion generated by the gas- 
burning device are released into the airstream being heated; 



2002 Edition 



54-10 



NATIONAL FUEL GAS CODE 



ANSI Z223. 1-10 



whose purpose is to offset the building heat loss by heating 
incoming outside air, inside air, or a combination of both. 

3.3.67 Direct Gas-Fired Makeup Air Heater. A heater in 
which all the products of combustion generated by the fuel- 
gas burning device are released into the outside airstream be- 
ing heated. 

3.3.68 Direct Vent Appliances. Appliances that are con- 
structed and installed so that all air for combustion is derived 
directly from the outside atmosphere and all flue gases are 
discharged to the outside atmosphere. 

3.3.69 Diversity Factor. Ratio of the mciximum probable de- 
mand to the maximum possible demand. 

3.3.70 Draft. A pressure difference that causes gases or air to 
flow through a chimney, vent, flue, or fuel burning equipment. 

3.3.71 Draft, Mechanical. Draft produced by a fan or an air 
or steam jet. When a fan is located so as to push the flue gases 
through the chimney or vent, the draft is forced. When the fan 
is located so as to pull the flue gases through the chimney or 
vent, the draft is induced. [211:1-5] 

3.3.72 Draft, Natural. Draft produced by the difference in 
the weight of a column of flue gases within a chimney or vent 
and a corresponding column of air of equal dimension out- 
side the chimney or vent. [211:1-5] 

3.3.73 Draft Hood. A nonadjustable device built into an ap- 
pliance, or made a part of the vent connector from an appli- 
ance, that is designed to (1) provide for the ready escape of 
the flue gases from the appliance in the event of no draft, 
backdraft, or stoppage beyond the draft hood, (2) prevent a 
backdraft from entering the appliance, and (3) neutralize the 
effect of stack action of the chimney or gas vent upon the 
operation of the appliance. 

3.3.74 Draft Regulator. A device that functions to maintain a 
desired draft in the appliance by automatically reducing the 
draft to the desired value. 

3.3.75 Drip. The container placed at a low point in a system 
of piping to collect condensate and from which it may be re- 
moved. 

3.3.76 Dry Gas. A gas having a moisture and hydrocarbon 
dew point below any normal temperature to which the gas 
piping is exposed. 

3.3.77 Duct Furnace. A furnace normally installed in distri- 
bution ducts of air conditioning systems to supply warm air for 
heating. This definition applies only to an appliance that de- 
pends for air circulation on a blower not furnished as part of 
the furnace. 

3.3.78 Effective Ground-Fault Current Path. An intention- 
ally constructed, permanent, low impedance electrically con- 
ductive path designed and intended to carry underground 
fault conditions from the point of a ground fault on a wiring 
system to the electrical supply source. 

3.3.79 Equipment. SeeAppliance. 

3.3.80 Excess Air. Air that passes through the combustion 
chamber and the appliance flues in excess of that which is 
theoretically required for complete combustion. 

3.3.81 Explosion Heads (Soft Heads or Rupture Discs). A 

protective device for relieving excessive pressure in a premix 
system by bursting of a rupturable disc. 



3.3.82 Exterior Masonry Chimneys. Masoniy chimneys ex- 
posed to the outdoors on one or more sides below the roof 
line. 

3.3.83 Fan-Assisted Combustion System. An appliance 
equipped with an integral mechanical means to either draw or 
force products of combustion throvigh the combustion cham- 
ber or heat exchanger. 

3.3.84 E\N Max. The maximum input rating of a Category I, 
fan-assisted appliance attached to a vent or connector. 

3.3.85 E^ Min. The minimum input rating of a Category 1, 
fan-assisted appliance attached to a vent or connector. 

3.3.86 E^+FAN. The maximum combined appliance input 
rating of two or more Category I, fan-assisted appliances at- 
tached to the common vent. 

3.3.87 Ef\N+NAT. The maximum combined appliance input 
rating of one or more Category I, fan-assisted appliances and 
one or more Category I, draft hood-equipped appliances at- 
tached to the common vent. 

3.3.88 Fireplace. A fire chamber and hearth constructed of 
noncombustible material for use with solid fuels and provided 
with a chimney. 

3.3.89 Flame Arrester. A nonvalve device for use in a gas-air 
mixture line containing a means for temporarily stopping the 
progress of a flame front (flashback) . 

3.3.90 Floor Furnace. A completely self-contained unit fur- 
nace suspended from the floor of the space being heated, tak- 
ing air for combustion from outside this space. 

3.3.91 Flue, Appliance. The passage(s) within an appliance 
through which combustion products pass from the combustion 
chamber of the appliance to the draft hood inlet opening on an 
appliance equipped with a draft hood or to the outiet of the 
appliance on an appliance not equipped with a draft hood. 

3.3.92 Flue, Chimney. The passage (s) in a chimney for con- 
veying the flue or vent gases to the outside atmosphere. 

3.3.93 Flue Collar. That portion of an appliance designed 
for the attachment of a draft hood, vent connector, or venting 
system. 

3.3.94 Flue Gases. Products of combustion plus excess air in 
appliance flues or heat exchangers. 

3.3.95 Food Service Equipment, Gas Counter Appliance. An 

appliance such as a gas coffee brewer and coffee urn and any 
appurtenant water heating equipment, food and dish warmer, 
hot plate, and griddle. 

3.3.96 Food Service Equipment, Gas Deep Fat Fryer. An ap- 
pliance, including a cooking vessel in which oils or fats are 
placed to such a depth that the cooking food is essentially 
supported by displacement of the cooking fluid or a perfo- 
rated container immersed in the cooking fluid rather than by 
the bottom of the vessel, designed primarily for use in hotels, 
restaurants, clubs, and similar institutions. 

3.3.97 Food Service Equipment, Gas-Fked Ketde. An appli- 
ance with a cooking chamber that is heated either by a steam 
jacket in which steam is generated by gas heat or by direct gas 
heat applied to the cooking chamber. 

3.3.98 Food Service Equipment, Gas Oven, Baking and Roast- 
ing. An oven primarily intended for volume food preparation 
that may be composed of one or more sections or units of the 



2002 Edition 



ANSI Z223. 1-11 



DEFINITIONS 



54-11 



following types: (1) cabinet oven, an oven having one or more 
cavities heated by a single burner or group of burners; (2) 
reel-type oven, an oven employing trays that are moved by 
mechanical means; or (3) sectional oven, an oven composed 
of one or more independently heated cavities. 

3.3.99 Food Service Equipment, Gas Range. A self- 
contained gas range providing for cooking, roasting, baking, 
or broiling, or any combination of these functions, and not 
designed specifically for domestic use. 

3.3.100 Food Service Equipment, Gas Steam Cooker. A gas 

appliance that cooks, defrosts, or reconstitutes food by direct 
contact wdth steam. 

3.3.101 Food Service Equipment, Gas Steam Generator. A 

separate appliance primarily intended to supply steam for use 
with food service equipment. 

3.3.102 Furnace, Central. A self-contained, gas-burning ap- 
pliance for heating air by transfer of heat of combustion 
through metal to the air and designed to supply heated air 
through ducts to spaces remote from or adjacent to the appli- 
ance location. 

3.3.103 Furnace, Enclosed. A specific heating, or heating 
and ventilating, furnace incorporating an integral total enclo- 
sure and using only outside air for combustion. 

3.3.104 Furnace, Forced-Air. A furnace equipped with a fan 
or blower that provides the primary means for circulation of 
air. 

3.3.105 Furnace Plenum. A compartment or chamber that is 
supplied vsdth the furnace or constructed of ductwork that is 
attached to the inlet or outlet of a furnace or air handling unit 
and has one or more circulating air ducts connected to it. 

3.3.106 Garage, Repair. A building, structure, or portions 
thereof wherein major repair or painting or body and fender 
work is performed on motorized vehicles or automobiles, and 
includes associated floor space used for offices, parking, and 
showrooms. 

3.3.107 Garage, Residential. A building or room in which 
self-propelled passenger vehicles are or can be stored and that 
will not normally be used for other than minor service or re- 
pair operations on such stored vehicles. 

3.3.108 Gas Fireplace, Direct Vent. A system consisting of 
(1) an appliance for indoor installation that allows the view of 
flames and provides the simulation of a solid fuel fireplace, (2) 
combustion air connections between the appliance and the 
vent-air intake terminal, (3) flue-gas connections between the 
appliance and the vent-air intake terminal, (4) a vent-air in- 
take terminal for installation outdoors, constructed such that 
all air for combustion is obtained from the outdoor atmo- 
sphere and all flue gases are discharged to the outdoor atmo- 
sphere. 

3.3.109 Gas Fireplace, Vented. A vented appliance that al- 
lows the view of flames and provides the simulation of a solid 
fuel fireplace. 

3.3.110 Gas-Mixing Machine. Any combination of automatic 
proportioning control devices, blowers, or compressors that 
supply mixtures of gas and air to multiple burner installations 
where control devices or other accessories are installed be- 
tween the mixing device and burner. 



3.3.111 Gas Utilization Equipment. Any device that utilizes 
gas as a fuel or raw material or both. 

3.3.112 Gas Vent. A passageway composed of listed factory- 
built components assembled in accordance with the terms of 
listing for conveying vent gases from gas appliances or their 
vent connectors to the outside atmosphere. 

3.3.113 Gas Vent, Special Type. Gas vents for venting listed 
Category II, III, and IV gas appliances. 

3.3.114 Gas Vent, Type B. A vent for venting listed gas appli- 
ances with draft hoods and other Category I gas appliances 
listed for use with Type B gas vents. 

3.3.115 Gas Vent, Type B-W. A vent for venting listed gas- 
fired vented wall furnaces. 

3.3.116 Gas Vent, Type L. Avent for venting appliances listed 
for use with Type L vents and appliances listed for use with 
Type B gas vents. 

3.3.117 Gases. Include natural gas, manufactured gas, lique- 
fied petroleum (LP) gas in the vapor phase only, liquefied 
petroleum gas-air mixtures, and mixtures of these gases, plus 
gas-air mixtures v«thin the flammable range, with the fuel gas 
or the flammable component of a mixture being a commer- 
cially distributed product. 

3.3.118 Governor, Zero. A regulating device that is normally 
adjusted to deliver gas at atmospheric pressure wdthin its flow 
rating. 

3.3.119 Gravity. 5ee Specific Gravity. 

3.3.120 Heat Pump, Gas-Fired. A gas-burning, automatically 
operated appliance utilizing a refrigeration system for supply- 
ing either heated air or liquid or heated and/or cooled air or 
liquid. 

3.3.121 Heating Value (Total). The number of British ther- 
mal units produced by the combustion, at constant pressure, 
of 1 ft^ (0.03 m^) of gas when the products of combustion are 
cooled to the initial temperature of the gas and air, when the 
water vapor formed during combustion is condensed, and 
when all the necessary corrections have been applied. 

3.3.122 Hoop Stress. The stress in a pipe wall, acting circum- 
ferentially in a plane perpendicular to the longitudinal axis of 
the pipe and produced by the pressure of the fluid in the pipe. 

3.3.123 Hot Plate. SeeFood Service Equipment, Gas Counter 
Appliance. 

3.3.124 Hot Plate, Domestic. A fuel-gas burning appliance 
consisting of one or more open-top-type burners mounted on 
short legs or a base. 

3.3.125 Hot Taps. Piping connections made to operating 
pipelines or mains or other facilities while they are in opera- 
tion. The connection of the branch piping to the operating 
line and the tapping of the operating line are done while it is 
under gas pressure. 

3.3.126 Household Cooking Gas Appliance. A gas appliance 
for domestic food preparation, providing at least one function of 
(1) top or surface cooking, (2) oven cooking, or (3) broiling. 

3.3. 1 27 Household Cooking Gas Appliance, Built-in Unit. A 

unit designed to be recessed into, placed upon, or attached to 
the construction of a building, but not for installation on the 
floor. 



2002 Edition 



54-12 



NATIONAL FUEL GAS CODE 



ANSIZ223.1-12 



3.3.128 Household Cooking Gas Appliance, Broiler. A unit 
that cooks primarily by radiated heat. 

3.3.129 Hybrid Pressure System. A piping system in which 
the pressure at the point of deUvery is reduced by one or more 
line pressure regulators prior to the appliance connection. 

3.3.130 Industrial Air Heaters, Direct Gas-Fired Non- 
Recirculating. A heater in which all the products of combus- 
tion generated by the gas-burning device are released into the 
air stream being heated to compensate for building heat loss 
by heating only incoming outside air. 

3.3.131 Industrial Air Heaters, Direct Gas-Fired Recirculat- 
ing. A heater in which all the products of combustion gener- 
ated by the gas-burning device are released into the air stream 
being heated to compensate for building heat loss by heating 
incoming outdoor air, and, if applicable, inside air. 

3.3.132 Infrared Heater. A heater that directs a substantial 
amount of its energy output in the form of infrared energy 
into the area to be heated. Such heaters may be of either the 
vented or unvented type. 

3.3.133 Insulating Millboard. A factory fabricated board 
formed with noncombustible materials, normally fibers, and 
having a thermal conductivity in the range of 1 Btu/in./ft^/ 
°F/hr (0.14W/m/°K). 

3.3.134 Joint. A connection between two lengths of pipe or 
between a length of pipe and a fitting. 

3.3.135 Ke trie, Gas-Fired. 5^e Food Service Equipment, Gas- 
Fired Kettle. 

3.3.136 Labeled. Equipment or materials to which has been 
attached a label, symbol, or other identifying mark of an orga- 
nization that is acceptable to the authority having jurisdiction 
and concerned with product evaluation, that maintains peri- 
odic inspection of production of labeled equipment or mate- 
rials, and by whose labeling the manufacturer indicates com- 
pliance with appropriate standards or performance in a 
specified manner. 

3.3.137 Laundry Stove, Domestic. A fuel-gas burning appli- 
ance consisting of one or more open-top-type burners 
mounted on high legs or having a cabinet base. 

3.3.138 Leak Check. An operation performed on a complete 
gas piping system and connected equipment to verify that the 
system does not leak. 

3.3.139 Limit Control. A device responsive to changes in 
pressure, temperature, or liquid level for turning on, shutting 
off, or throttling the gas supply to an appliance. 

3.3.140* Listed. Equipment, materials, or services included 
in a list published by an organization that is acceptable to the 
authority having jurisdiction and concerned with evaluation 
of products or services, that maintains periodic inspection of 
production of listed equipment or materials or periodic evalu- 
ation of services, and whose listing states that either the equip- 
ment, material, or service meets appropriate designated stan- 
dards or has been tested and found suitable for a specified 
purpose. 

3.3.141 Main Burner. A device or group of devices essentially 
forming an integral unit for the final conveyance of gas or a 
mixture of gas and air to the combustion zone and on which 
combustion takes place to accomplish the function for which 
the appliance is designed. 



3.3.142 Manifold, Gas. The conduit of an appliance that 
supplies gas to the individual burners. 

3.3.143 Manufactured Home. A structure, transportable in 
one or more sections, that is 8 body-ft (24.4 cm) or more in 
width or 40 body-ft (1219 cm) or more in length in the travel- 
ing mode or, when erected on site, is 320 ft^ (28 m^) or more; 
which is built on a chassis and designed to be used as a dwell- 
ing, with or without a permanent foundation, when con- 
nected to the required utilities, including the plumbing, heat- 
ing, air conditioning, and electrical systems contained 
therein. Calculations used to determine the number of square 
feet in a structure will be based on a structure's exterior di- 
mensions, measured at the largest horizontal projections 
when erected on site. These dimensions include all expand- 
able rooms, cabinets, and other projections containing inte- 
rior space, but do not include bay v^ndows. [501:1.2] 

3.3.144 Maximum Working Pressure. The maximum pres- 
sure at which a piping system may be operated in accordance 
with the provisions of this code. 

3.3.145 Mechanical Exhaust System. Equipment installed in 
and made a part of the vent, which will provide a positive in- 
duced draft. 

3.3.146 Meter. An instrument installed to measure the vol- 
ume of gas delivered through it. 

3.3.147 Mixing Blower. A motor-driven blower to produce 
gas-air mixtures for combustion through one or more gas 
burners or nozzles on a single-zone industrial heating appli- 
ance or on each control zone of a multizone industrial appli- 
ance or on each control zone of a multizone installation. 

3.3.148 NA. Vent configuration is not allowed due to poten- 
tial for condensate formation or pressurization of the venting 
system, or not applicable due to physical or geometric re- 
straints. 

3.3.149 NAT Max. The maximum input rating of a Category 
I, draft hood-equipped appliance attached to a vent or con- 
nector. 

3.3.150 NAT+NAT. The maximum combined appliance in- 
put rating of two or more Category I, draft hood-equipped 
appliances attached to the common vent. 

3.3.151 Noncombustible Material. For the purpose of this 
code, noncombustible material shall mean material that is not 
capable of being ignited and burned, such as material consist- 
ing entirely of, or of a combination of, steel, iron, brick, tile, 
concrete, slate, asbestos, glass, and plaster. 

3.3.152 Nondisplaceable Valve Member. A nondisplaceable 
valve member that cannot be moved from its seat by a force 
applied to the handle or by a force applied by a plane surface 
to any exterior portion of the valve. 

3.3.153 Occupancy, Health Care. An occupancy used for 
purposes of medical or other treatment or care of four or 
more persons where such occupants are mostiy incapable of 
self-preservation due to age, physical or mental disability, or 
because of security measures not under the occupants' con- 
trol. [10/: 3.3.134.7] 

3.3.154 Occupancy, Residential Board and Care. A building 
or portion thereof that is used for lodging and boarding of 
four or more residents, not related by blood or marriage to 
the owners or operators, for the purpose of providing per- 
sonal care services. [101: 3.3.134.13] 



2002 Edition 



ANSIZ223.1-13 



DEFINITIONS 



54-13 



3.3. 155 Offset, Vent. An arrangement of two or more fittings 
and pipe installed for the purpose of locating a vertical section 
of vent pipe in a different but parallel plane with respect to an 
adjacent section of vertical vent pipe. 

3.3.156 Orifice. The opening in a cap, spud, or other device 
whereby the flow of gas is limited and through which the gas is 
discharged to the burner. 

3.3.157 Outdoor Cooking Gas Appliance. As used in this 
code, a post-mounted, fuel-gas burning outdoor cooking ap- 
pliance for installation directly on and attachment to a post 
provided as a part of the appliance by the manufacturer. 

3.3.158 Oven, Gas Baking and Roasting. See Food Service 
Equipment, Gas Oven. 

3.3.159 Parking Structure. A building, structure, or portion 
thereof used for the parking of motor vehicles. 

3.3.160 Parking Structure, Basement or Underground. A 

parking structure or portion thereof located below grade. 

3.3.161 Parking Structure, Enclosed. Having exterior enclos- 
ing walls that have less than 25 percent of the total wail area 
open to atmosphere at each level using at least two sides of the 
structure. 

3.3.162 PUot. A small flame that is uulized to ignite the gas at 
the main burner or burners. 

3.3.163 Pipe. Rigid conduit of iron, steel, copper, brass, alu- 
minum, or plastic. 

3.3.164 Pipe, Equivalent Length. The resistance of valves, 
controls, and fittings to gas flow expressed as equivalent 
length of straight pipe for convenience in calculating pipe 
sizes. 

3.3.165 Piping. As used in this code, either pipe, tubing, or 
both. SeeFipe, Tubing. 

3.3.166 Piping System. All piping, valves, and fittings from 
the oudet of the point of delivery from the supplier to the 
outlets of the equipment shutofiF valves. 

3.3.167 Plenum. A compartment or chamber to which one 
or more ducts are connected and that forms part of the air 
distribution system. 

3.3.168 Pool Heater. An appliance designed for heating non- 
potable water stored at atmospheric pressure, such as water in 
swimming pools, therapeutic pools, and similar applications. 

3.3.169 Pressure. Unless otherwise stated, is expressed in 
pounds per square inch above atmospheric pressure. 

3.3.170 Pressure Drop. The loss in pressure due to friction or 
obstruction in pipes, valves, fittings, regulators, and burners. 

3.3.171 Pressiu"e Limiting Device. Equipment that under ab- 
normal conditions will act to reduce, restrict, or shut off the 
supply of gas flowing into a system in order to prevent the gas 
pressure in that system from exceeding a predetermined 
value. 

3.3.172 Pressure Test. An operation performed to verify the 
gastight integrity of gas piping following its installation or 
modification. 

3.3.173 Primary Air. The air introduced into a burner that 
mixes with the gas before it reaches the port or ports. 



3.3.174 Purge. To free a gas conduit of air or gas, or a mix- 
ture of gas and air. 

3.3.175 Qualified Agency. Any individual, firm, corporation, 
or company that either in person or through a representative 
is engaged in and is responsible for (a) the installation, test- 
ing, or replacement of gas piping or (b) the connection, in- 
stallation, testing, repair, or servicing of equipment; that is 
experienced in such work; that is familiar with all precautions 
required; and that has complied with all the requirements of 
the authority having jurisdiction. 

3.3.176 Quick-Disconnect Device. A hand-operated device 
that provides a means for connecting and disconnecting an 
appliance or an appliance connector to a gas supply and that is 
equipped with an automatic means to shut off the gas supply 
when the device is disconnected. 

3.3.177 Range. See^ood Service Equipment, Gas Range. 

3.3.178 Refrigerator (Using Gas Fuel). A fuel-gas-burning 
appliance that is designed to extract heat from a suitable 
chamber. 

3.3.179 Regulator, Gas Appliance. A pressure regulator for 
controlling pressure to the manifold of gas equipment. 

3.3.180 Regulator, Line Gas. Apressureregulator placedin a 
gas line between the service regulator and the gas appliance 
regulator. 

3.3.181 Regulator, Monitoring. A pressure regulator set in 
series with another pressure regulator for the purpose of auto- 
matically taking over in an emergency the control of the pres- 
sure downstream of the regulator in case that pressure tends 
to exceed a set maximum. 

3.3.182 Regulator, Pressure. A device placed in a gas line for 
reducing, controlling, and maintaining the pressure in that 
portion of the piping system downstream of the device. 

3.3.183 Regulator, Series. A pressure regulator in series with 
one or more other pressure regulators. 

3.3.184 Regulator, Service. A pressure regulator installed by 
the serving gas supplier to reduce and limit the service line gas 
pressure to delivery pressure. 

3.3.185 Regulator Vent. The opening in the atmospheric 
side of the regulator housing permitting the in and out move- 
ment of air to compensate for the movement of the regulator 
diaphragm. 

3.3.186 Relief Opening. The opening provided in a draft 
hood to permit the ready escape to the atmosphere of the flue 
products from the draft hood in the event of no draft, back- 
draft, or stoppage beyond the draft hood and to permit inspi- 
ration of air into the draft hood in the event of a strong chim- 
ney updraft. 

3.3.187 Room Heater, Unvented. An unvented, self- 
contained, freestanding, nonrecessed, fuel-gas-burning appli- 
ance for furnishing warm air by gravity or fan circulation to 
the space in which installed, directly from the heater without 
duct connection. 

3.3.188 Room Lai^e in Comparison with Size of Equipment. 

Rooms having a volume equal to at least 12 times the total 
volume of a furnace or air-conditioning appliance and at least 
16 times the total volume of a boiler. 



2002 Edition 



54-14 



NATIONAL FUEL GAS CODE 



ANSIZ223.1-14 



3.3.189 Safety Blowout (Backfire Preventer). A protective 
device located in the discharge piping of large mixing ma- 
chines, incorporating a bursting disc for excessive pressure 
release, means for stopping a flame front, and an electric 
switch or other release mechanism for actuating a built-in or 
separate safety shutofiF. 

3.3.190 Safety Shutoff Device. A device that will shut off the 
gas supply to the controlled burner(s) in the event the source 
of ignition fails. This device can interrupt the flow of gas to 
main burner(s) only or to pilot(s) and main burner(s) under 
its supervision. 

3.3.191 Service Head Adapter. A transition fitting for use 
with plastic piping (which is encased in non-pressure-carrying 
metal pipe) that connects the metal pipe casing and plastic 
pipe and tubing to the remainder of the piping system. 

3.3.192 Service Meter Assembly. The piping and fittings in- 
stalled by the serving gas supplier to connect the inlet side of 
the meter to the gas service and to connect the outlet side of 
the meter to the customer's house or yard piping. 

3.3.193 Service Regulator. &g Regulator, Pressure and Regu- 
lator, Service. 

3.3.194 Shall. Indicates a mandatory requirement. 

3.3.195 Shutoff. SeeYa.\\e. 

3.3.196 Sources of Ignition. Devices or equipment that, be- 
cause of their intended modes of use or operation, are capable 
of providing sufficient thermal energy to ignite flammable 
gas-air mixtures. 

3.3.197 Specific Gravity. As applied to gas, the ratio of the 
weight of a given volume to that of the same volume of air, 
both measured under the same conditions. 

3.3.198 Steam Cooker. See Food Service Equipment, Gas 
Steam Cooker. 

3.3.199 Steam Generator. Se^Food Service Equipment, Gas 
Steam Generator. 

3.3.200 Stress. The resultant internal force that resists 
change in the size or shape of a body acted on by external 
forces. In this code, stress is often used as being synonymous 
with unit stress, which is the stress per unit area (psi). 

3.3.201 Tensile Strength. The highest unit tensile stress (re- 
ferred to the original cross section) a material can sustain be- 
fore failure (psi). 

3.3.202 Thermostat, Electric Switch Type. A device that 
senses changes in temperature and controls electrically, by 
means of separate components, the flow of gas to the burn- 
er(s) to maintain selected temperatures. 

3.3.203 Thermostat, Integral Gas Valve Type. An automatic 
device, actuated by temperature changes, designed to control 
the gas supply to the burner (s) in order to maintain tempera- 
tures between predetermined limits and in which the thermal 
actuating element is an integral part of the device: (1) gradu- 
ating thermostat, a thermostat in which the motion of the 
valve is approximately in direct proportion to the effective mo- 
tion of the thermal element induced by temperature change; 
(2) snap-acting thermostat, a thermostat in which the thermo- 
static valve travels instantly from the closed to the open posi- 
tion, and vice versa. 



3.3.204 Thread Joint Compoimds. Nonhardening materials 
used on pipe threads to ensure a seal. 

3.3.205 Tubing. Semirigid conduit of copper, steel, alumi- 
num, or plastic. 

3.3.206 Type B Gas Vent. See Gas Vent, Type B. 

3.3.207 Type B-W Gas Vent. See Gas Vent, Type B-W. 

3.3.208 Type L Vent. See Gas Vent, Type L. 

3.3.209 Unit BroUer. A broiler constructed as a separate ap- 
pliance. 

3.3.210 Unit Heater, High-Static Pressure Type. A self- 
contained, automatically controlled, vented, fuel-gas-burning 
appliance having integral means for circulation of air against 
0.2 in. (15 mm) HgO or greater static pressure. 

3.3.211 Unit Heater, Low-Static Pressure Type. A self- 
contained, automatically controlled, vented, fuel-gas burning 
appliance, intended for installation in the space to be heated 
without the use of ducts, having integral means for circulation 
of air, normally by a propeller fan(s), and may be equipped 
with louvers or face extensions made in accordance with the 
manufacturers' specifications. 

3.3.212 Utility Gases. Natural gas, manufactured gas, lique- 
fied petroleum gas-air mixtures, or mixtures of any of these 
gases. 

3.3.213 Valve. A device used in piping to control the gas sup- 
ply to any section of a system of piping or to an appliance. 

3.3.214 Valve, Automatic. An automatic or semiautomatic 
device consisting essentially of a valve and operator that con- 
trol the gas supply to the burner (s) during operation of an 
appliance. 

3.3.215 Valve, Equipment Shutoff . A valve located in the pip- 
ing system, used to shut off individual equipment. 

3.3.216 Valve, Manual Reset. An automatic shutoff valve in- 
stalled in the gas supply piping and set to shut off when unsafe 
conditions occur. The device remains closed until manually 
reopened. 

3.3.217 Valve, Pressure ReUef. A valve that automatically 
opens and closes a relief vent, depending on whether the pres- 
sure is above or below a predetermined value. 

3.3.218 Valve, Relief. A safety valve designed to forestall the 
development of a dangerous condition by relieving either 
pressure, temperature, or vacuum in a hot water supply sys- 
tem. 

3.3.219 Valve, Service Shutoff. A valve, installed by the serv- 
ing gas supplier between the service meter or source of supply 
and the customer piping system, to shut off the entire piping 
system. 

3.3.220 Valve, Temperature Relief. A valve that automati- 
cally opens and automatically closes a relief vent, depending 
on whether the temperature is above or below a predeter- 
mined value. 

3.3.221 Valve, Vacuum Relief. A valve that automatically 
opens and closes a vent for relieving a vacuum within the hot 
water supply system, depending on whether the vacuum is 
above or below a predetermined value. 



2002 Edition 



ANSI Z223.1-15 



GENERAL 



54-15 



3.3.222 Valve Member. That part of a gas valve rotating 
within or in respect to the valve body that, by its position with 
respect to the valve body, controls the flow of gas. 

3.3.223 Vent. A passageway used to convey flue gases from 
gas utilization equipment or their vent connectors to the out- 
side atmosphere. 

3.3.224 Vent Connector. The pipe or duct that connects a 
fuel-gas-burning appliance to a vent or chimney. 

3.3.225 Vent Damper Device, Automatic. A device that is in- 
tended for installation in the venting system, in the oudet of or 
downstream of the appliance draft hood, of an individual au- 
tomatically operated fuel-gas-burning appliance and that is de- 
signed to automatically open the vendng system when the ap- 
pliance is in operation and to automatically close off the 
venting system when the appliance is in a standby or shutdown 
condition. 

3.3.226 Vent Damper Device, Automatic, Electrically Oper- 
ated. An automatic vent damper device that employs electri- 
cal energy to control the device. 

3.3.227 Vent Damper Device, Automatic, Mechanically Actu- 
ated. An automatic vent damper device dependent for opera- 
tion on the direct application or transmission of mechanical 
energy without employing any type of energy conversion. 

3.3.228 Vent Damper Device, Automatic, Thermally Actuated. 

An automatic vent damper device dependent for operation 
exclusively on the direct conversion of the thermal energy of 
the vent gases into mechanical energy. 

3.3.229 Vent Gases. Products of combustion from fuel-gas- 
burning appliances plus excess air, plus dilution air in the 
venting system above the draft hood or draft regulator. 

3.3.230* Vented Appliance, Category I. An appliance that 
operates with a nonpositive vent static pressure and with a vent 
gas temperature that avoids excessive condensate production 
in the vent. 

3.3.231 Vented Appliance, Category II. An appliance that 
operates with a nonpositive vent static pressure and with a vent 
gas temperature that may cause excessive condensate produc- 
tion in the vent. 

3.3.232 Vented Appliance, Category III. An appliance that 
operates with a positive vent static pressure and with a vent gas 
temperature that avoids excessive condensate production in 
the vent. 

3.3.233 Vented AppUance, Category IV. An appliance that 
operates with a positive vent static pressure and with a vent gas 
temperature that may cause excessive condensate production 
in the vent. 

3.3.234 Vented Wall Furnace. A self-contained, vented, fuel- 
gas-burning appliance complete with grilles or equivalent, de- 
signed for incorporation in or permanent attachment to the 
structure of a building and furnishing heated air, circulated by 
gravity or by a fan, directly into the space to be heated through 
openings in the casing. 

3.3.235 Venting. Removal of combustion products as well as 
process fumes to the outer air. 

3.3.236* Venting System. A continuous open passageway 
from the flue collar or draft hood of a gas-burning appliance 
to the outside atmosphere for the purpose of removing flue or 
vent gases. 



3.3.237 Venting System, Mechanical Draft. A venting system 
designed to remove flue or vent gases by mechanical means, 
which may consist of an induced draft portion under nonposi- 
tive static pressure or a forced draft portion under positive 
static pressure. 

3.3.238 Venting System, Mechanical Draft, Forced. Aventing 
system in which a fan or other mechanical device is used to 
cause the flow of flue or vent gases under positive static vent 
pressure. 

3.3.239 Venting System, Natural Draft. Aventing system that 
relies on natural draft to convey the products of combustion. 

3.3.240 Wall Furnace, Direct Vent. A system consisting of an 
appliance, combustion air, and flue gas connections between 
the appliance and the outdoor atmosphere, and a vent cap 
supplied by the manufacturer and constructed so that all air 
for combustion is obtained from the outdoor atmosphere and 
all flue gases are discharged to the outdoor atmosphere. 

3.3.241 Wall Head Adapter. A transition fitting for terminat- 
ing plastic pipe inside of buildings at the building wall. 

3.3.242 Water Heater. An appliance for supplying hot water 
for domestic or commercial purposes. 



Chapter 4 General 

4.1 Qualified Agency. Installation, testing, and replacement 
of gas piping, gas utilization equipment, or accessories, and 
repair and servicing of equipment, shall be performed only by 
a qualified agency. 

4.2 Interruption of Service. 

4.2.1 Notification of Interrupted Service. When the gas sup- 
ply is to be turned off, it shall be the duty of the qualified 
agency to notify all affected users. Where two or more users 
are served from the same supply system, precautions shall be 
exercised to ensure that service only to the proper user is 
turned off. 

Exception: In cases of emergency, affected users shall be notified as 
soon as possible of the actions taken by the qualified agency. 

4.2.2 Work Interruptions. When interruptions in work occur 
while repairs or alterations are being made to an existing pip- 
ing system, the system shall be left in a safe condition. 

4.3 Prevention of Accidental Ignition. 

4.3.1 Potential Ignition Sources. Where work is being per- 
formed on piping that contains or has contained gas, the fol- 
lowing shall apply: 

(1) Provisions for electrical continuity shall be made before 
alterations are made in a metallic piping system. 

(2) Smoking, open flames, lanterns, welding, or other 
sources of ignition shall not be permitted. 

(3) A metallic electrical bond shall be installed around the 
location of cuts in metallic gas pipes made by other than 
cutting torches. Where cutting torches, welding, or other 
sources of ignition are unavoidable, it shall be deter- 
mined that all sources of gas or gas-air mixtures have 
been secured and that all flammable gas or liquids have 
been cleared from the area. Piping shall be purged as 
required in Section 7.3 before welding or cutting with a 
torch is attempted. 



2002 Edition 



54-16 



NATIONAL FUEL GAS CODE 



ANSIZ223.1-16 



(4) Artificial illumination shall be restricted to listed safety- 
type flashlights and safety lamps. Electric switches shall 
not be operated, on or off. 

4.3.2 Handling of Flammable Liquids. 

4.3.2.1 Drip Liquids. Liquid that is removed from a drip in 
existing gas piping shall be handled to avoid spillage or igni- 
tion. The gas supplier shall be notified when drip liquids are 
removed. 

4.3.2.2 Other Flanunable Liquids. Flammable liquids used by 
the installer shall be handled with precautions and shall not 
be left within the premises from the end of one working day to 
the beginning of the next. 



Chapter 5 Gas Piping System Design, Materials, 
and Components 

5.1 Piping Plan. 

5.1.1 Installation of Piping System. Where required by the 
authority having jurisdiction, a piping sketch or plan shall be 
prepared before proceeding with the installation. This plan 
shall show the proposed location of piping, the size of differ- 
ent branches, the various load demands, and the location of 
the point of delivery. 

5.1.2 Addition to Existing System. When additional gas utili- 
zation equipment is being connected to a gas piping system, 
the existing piping shall be checked to determine whether it 
has adequate capacity (see 5.4.3). If inadequate, the existing 
system shall be enlarged as required, or separate gas piping of 
adequate capacity shall be provided. 

5.2 Provision for Location of Point of Delivery. The location 
of the point of delivery shall be acceptable to the serving gas 
supplier. 

5.3 Interconnections Between Gas Piping Systems. 

5.3.1 Interconnections Supplying Separate Users. Where two 
or more meters, or two or more service regulators where 
meters are not provided, are located on the same premises 
and supply separate users, the gas piping systems shall not be 
interconnected on the outlet side of the meters or service 
regulators. 

5.3.2 Interconnections for Standby Fuels. Where a supple- 
mentary gas for standby use is connected downstream from a 
meter or a service regulator where a meter is not provided, a 
device to prevent backflow shall be installed. A three-way valve 
installed to admit the standby supply and at the same time shut 
off the regular supply shall be permitted to be used for this 
purpose. 

5.4 Sizing of Gas Piping Systems. 

5.4.1* General Considerations. Gas piping systems shall be of 
such size and so installed as to provide a supply of gas suffi- 
cient to meet the maximum demand without undue loss of 
pressure between the point of delivery and the gas utilization 
equipment. 

5.4.2* Maximum Gas Demand. 

5.4.2.1 The volume of gas to be provided (in cubic feet per 
hour) shall be determined directly from the manufacturers' 
input ratings of the gas utilization equipment served. Where 
the input rating is not indicated, the gas supplier, equipment 



manufacturer, or a qualified agency shall be contacted, or the 
rating from Table 5.4.2.1 shall be used for estimating the vol- 
ume of gas to be supplied. 

Table 5.4.2.1 Approximate Gas Input for Typical Appliances 



Appliance 


Input Btu/hr (Approx.) 


Space Heating Units 




Warm air furnace 




Single family 


100,000 


Multifamily, per unit 


60,000 


Hydronic boiler 




Single family 


100,000 


Multifamily, per unit 


60,000 


Space and Water Heating Units 




Hydronic boiler 




Single family 


120,000 


Multifamily, per unit 


75,000 


Water Heating Appliances 




Water heater, automatic 


35,000 


storage 30 gal to 40 gal tank 




Water heater, automatic 


50,000 


storage 50 gal tank 




Water heater, automatic 




instantaneous 




Capacity at 2 gal/min 


142,800 


Capacity at 4 gal/min 


285,000 


Capacity at 6 gal/min 


428,400 


Water heater, domestic, 


35,000 


circulating or side-arm 




Cooking Appliances 




Range, free standing. 


65,000 


domestic 




Built-in oven or broiler unit. 


25,000 


domestic 




Built-in top unit, domestic 


40,000 


Other Appliances 




Refrigerator 


3,000 


Clothes dryer. Type 1 


35,000 


(domestic) 




Gas fireplace direct vent 


40,000 


Gas log 


80,000 


Barbecue 


40,000 


Gas light 


2,500 



I For SI units, 1 Btu/hr = 0.293 W. 

5.4.2.2 The total connected hourly load shall be used as the 
basis for piping sizing, assuming all equipment is operating at 
full capacity simultaneously. 

Exception: Sizing shall be permitted to be based upon established load 
diversity factors. 

5.4.3* Sizing Methods. Gas piping shall be sized in accordance 
with one of the following: 

(1) Pipe sizing tables or sizing equations in Chapter 9 

(2) Other approved engineering methods acceptable to the 
authority having jurisdiction 

(3) Sizing tables included in a listed piping system manufac- 
turer's installation instructions 

5.4.4 Allowable Pressure Drop. The design pressure loss in 
any piping system under maximum probable flow conditions. 



2002 Edition 



ANSIZ223.1-17 



GAS PIPING SYSTEM DESIGN, MATERIALS, AND COMPONENTS 



54-17 



from the point of delivery to the inlet connection of the gas 
utilization equipment, shall be such that the supply pressure 
at the equipment is greater than the minimurh pressure re- 
quired for proper equipment operation. 

5.5 Piping System Operating Pressure Limitations. 

5.5.1 Maximum Design Operating Pressure. The maximum 
design operating pressure for piping systems located inside 
buildings shall not exceed 5 psi (34 kPa) unless one or more of 
the following conditions are met: 

(l)*The piping system is welded. 

(2) The piping is located in a ventilated chase or otherwise 
enclosed for protection against accidental gas accumula- 
tion. 

(3) The piping is located inside buildings or separate areas of 
buildings used exclusively for one of the following: 

(a) Industrial processing or heating 

(b) Research 

(c) Warehousing 

(d) Boiler or mechanical equipment rooms 

(4) The piping is a temporary installation for buildings under 
construction. 

5.5.2 Liquefied Petroleum Gas Systems. The operating pres- 
sure for undiluted LP-Gas systems shall not exceed 20 psi 
(140 kPa). Buildings having systems designed to operate 
below -5°F (-21 °C) or with butane or a propane-butane mix 
shall be designed to either accommodate liquid LP-Gas or pre- 
vent LP-Gas vapor from condensing back into a liquid. 

Exception: Buildings or separate areas of buildings constructed in 
accordance with Chapter 7 of NFPA 58, Liquefied Petroleum Gas 
Code, and used exclusively to house industrial processes, research and 
experimental laboratories, or equipment or processing having similar 
hazards. 

5.6 Acceptable Piping Materials and Joining Methods. 

5.6.1 General. 

5.6.1.1 Acceptable Materials. Materials used for piping sys- 
tems shall comply with the requirements of this chapter or 
shall be acceptable to the authority havingjurisdiction. 

5.6.1.2 Used Materials. Pipe, fittings, valves, or other materi- 
als shall not be used again unless they are free of foreign ma- 
terials and have been ascertained to be adequate for the ser- 
vice intended. 

5.6.1.3 Other Materials. Material not covered by the stan- 
dards specifications listed herein shall be investigated and 
tested to determine that it is safe and suitable for the proposed 
service and, in addition, shall be recommended for that ser- 
vice by the manufacturer and shall be acceptable to the au- 
thority havingjurisdiction. 

5.6.2 Metallic Pipe. 

5.6.2.1 Cast Iron. Cast-iron pipe shall not be used. 

5.6.2.2 Steel and Wrought Iron. Steel and wrought-iron pipe 
shall be at least of standard weight (Schedule 40) and shall 
comply with one of the following standards: 

( 1 ) ANSI/ASME B36. 10, Welded and Seamless Wrought-Steel Pipe 

(2) ASTM A 53, Standard Specification for Pipe, Steel, Black and 
Hot-Dipped, Zinc-Coated Welded and Seamless 

(3) ASTM A 106, Standard Specification for Seamless Carbon Steel 
Pipe for High-Temperature Service 



5.6.2.3* Copper and Brass. Copper and brass pipe shall not be 
used if the gas contains more than an average of 0.3 grains of 
hydrogen sulfide per 100 scf of gas (0.7 mg/100 L). 

5.6.2.4 Threaded Copper, Brass, and Aluminum. Threaded 
copper, brass, or aluminum alloy pipe shall not be used with 
gases corrosive to such material. 

5.6.2.5 Aluminum Alloy. Aluminum alloy pipe shall comply 
with ASTM B 241, Specification for Aluminum-Alloy Seamless Pipe 
and Seamless Extruded Tube (except that the use of alloy 5456 is 
prohibited) and shall be marked at each end of each length 
indicating compliance. Aluminum alloy pipe shall be coated 
to protect against external corrosion where it is in contact with 
masonry, plaster, or insulation or is subject to repeated wet- 
tings by such liquids as water, detergents, or sewage. 

5.6.2.6 Aluminum Installation. Aluminum alloy pipe shall not 
be used in exterior locations or underground. 

5.6.3 Metallic Tubing. Seamless copper, aluminum alloy, or 
steel tubing shall not be used with gases corrosive to such 
material. 

5.6.3.1 Steel. Steel tubing shall comply with ASTM A 539, Stan- 
dard Specification for Electric Resistance-Welded Coiled Steel Tubing 
for Gas and Fuel Oil Lines, or ASTM A 254, Standard Specification 
for Copper Brazed Steel Tubing. 

5.6.3.2* Copper and Brass. Copper and brass tubing shall not 
be used if the gas contains more than an average of 0.3 grains 
of hydrogen sulfide per 100 scf of gas (0.7 mg/100 L). Copper 
tubing shall comply with standard Type K or L of ASTM B 88, 
Specification for Seamless Copper Water Tube, or ASTM B 280, Speci- 
fication for Seamless Copper Tube for Air Conditioning and Refrigera- 
tion Field Service. 

5.6.3.3 Aluminum. Aluminum alloy tubing shall comply with 
ASTM B 210, Specification for Aluminum-Alloy Drawn Seamless 
Tubes, or ASTM B 241, Specification for Aluminum-Alloy Seamless 
Pipe and Seamless Extruded Tube. Aluminum alloy tubing shall be 
coated to protect against external corrosion where it is in con- 
tact with masonry, plaster, or insulation or is subject to re- 
peated wettings by such liquids as water, detergent, or sewage. 
Aluminum alloy tubing shall not be used in exterior locations 
or underground. 

5.6.3.4 Corrugated Stainless Steel. Corrugated stainless steel 
tubing shall be tested and listed in compliance with the con- 
struction, installation, and performance requirements of 
ANSI LC 1/CSA 6.26, Fuel Gas Piping Systems Using Corrugated 
Stainless Steel Tubing. 

5.6.4 Plastic Pipe, Tubing, and Fittings. Plastic pipe, tubing, 
and fittings shall be used outside underground only and shall 
conform with ASTM D 2513, Standard Specification for Thermo- 
plastic Gas Pressure Pipe, Tubing, and Fittings. Pipe to be used 
shall be marked "gas" and "ASTM D 2513." 

5.6.4.1 Anodeless Risers. Anodeless risers shall comply with 
the following: 

(1) Factory-assembled anodeless risers shall be recom- 
mended by the manufacturer for the gas used and shall be 
leak tested by the manufacturer in accordance with writ- 
ten procedures. 

(2) Service head adapters and field-assembled anodeless ris- 
ers incorporating service head adapters shall be recom- 
mended by the manufacturer for the gas used by the 
manufacturer and shall be design-certified to meet the 



2002 Edition 



54-18 



NATIONAL FUEL GAS CODE 



ANSIZ223.1-18 



requirements of Category I of ASTM D 2513, Standard 
Specification for Thermoplastic Gas Pressure Pipe, Tubing, and 
Fittings, and 49 CFR 192.281(e). The manufacturer shall 
provide the user qualified installation instructions as pre- 
scribed by 49 CFR 192.283(b). 
(3) The use of plastic pipe, tubing, and fittings in undiluted 
liquefied petroleum gas piping systems shall be in accor- 
dance with NFPA 58, Liquefied Petroleum Gas Code. 

5.6.5 Workmanship and Defects. Gas pipe, tubing, and fit- 
tings shall be clear and free from cutting burrs and defects in 
structure or threading and shall be thoroughly brushed, and 
chip and scale blown. Defects in pipe, tubing, and fittings shall 
not be repaired. Defective pipe, tubing, and fittings shall be 
replaced. [See 7.1.1.3.] 

5.6.6 Protective Coating. Where in contact with material or 
atmosphere exerting a corrosive action, metallic piping and 
fittings coated with a corrosion-resistant material shall be 
used. External or internal coatings or linings used on piping 
or components shall not be considered as adding strength. 

5.6.7 Metallic Pipe Threads. 

5.6.7.1 Specifications for Pipe Threads. Metallic pipe and fit- 
ting threads shall be taper pipe threads and shall comply with 
ANSI/ASME Bl.20.1, Pipe Threads, General Purpose, Inch. 

5.6.7.2 Damaged Threads. Pipe with threads that are 
stripped, chipped, corroded, or otherwise damaged shall not 
be used. Where a weld opens during the operation of cutting 
or threading, that portion of the pipe shall not be used. 

5.6.7.3 Nmnber of Threads. Field threading of metallic pipe 
shall be in accordance with Table 5.6.7.3. 



Table 5.6.7.3 Specifications for Threading Metallic Pipe 



Iron Pipe 
Size 


Approximate 

Length of 

Threaded Portion 


Approximate 
No. of Threads 


(in.) 


(in.) 


to Be Cut 


1/2 


3/4 


10 


3/4 


3/4 


10 


1 


% 


10 


11/4 


1 


11 


11/2 


1 


11 


2 


1 


11 


21/2 


11/2 


12 


3 


11/2 


12 


4 


1% 


13 



For SI units, 1 in. = 25.4 mm. 



5.6.7.4 Thread Compounds. Thread (joint) compounds 
(pipe dope) shall be resistant to the action of liquefied petro- 
leum gas or to any other chemical constituents of the gases to 
be conducted through the piping. 

5.6.8 Metallic Piping Joints and Fittings. The type of piping 
joint used shall be suitable for the pressure-temperature con- 
ditions and shall be selected giving consideration to joint 
tightness and mechanical strength under the service condi- 
tions. The joint shall be able to sustain the maximum end 
force due to the internal pressure and any additional forces 



due to temperature expansion or contraction, vibration, fa- 
tigue, or the weight of the pipe and its contents. 

5.6.8.1* Pipe Joints. Pipe joints shall be threaded, flanged, 
brazed, or welded. Where nonferrous pipe is brazed, the braz- 
ing materials shall have a melting point in excess of 1000°F 
(538°C). Brazing alloys shall not contain more than 0.05 per- 
cent phosphorus. 

5.6.8.2 Tubing Joints. Tubing joints shall either be made with 
approved gas tubing fittings or be brazed with a material hav- 
ing a melting point in excess of 1000°F (538°C) . Brazing alloys 
shall not contain more than 0.05 percent phosphorus. 

5.6.8.3 Flared Joints. Flared joints shall be used only in sys- 
tems constructed from nonferrous pipe and tubing where ex- 
perience or tests have demonstrated that the joint is suitable 
for the conditions and where provisions are made in the de- 
sign to prevent separation of the joints. 

5.6.8.4 Metallic Fittings (Including Valves, Strainers, Filters). 

Metallic fittings shall comply with the following: 

(1) Threaded fittings in sizes larger than 4 in. (100 mm) shall 
not be used unless acceptable to the authority having ju- 
risdiction. 

(2) Fittings used with steel or wrought-iron pipe shall be steel, 
brass, bronze, malleable iron, or cast iron. 

(3) Fittings used with copper or brass pipe shall be copper, 
brass, or bronze. 

(4) Fittings used with aluminum alloy pipe shall be of alumi- 
num alloy. 

(5) Cast-Iron Fittings. Cast-iron fittings shall comply with the 
following: 

(a) Flanges shall be permitted. 

(b) Bushings shall not be used. 

(c) Fittings shall not be used in systems containing flam- 
mable gas-air mixtures. 

(d) Fittings in sizes 4 in. (100 mm) and larger shall not be 
used indoors unless approved by the authority having 
jurisdiction. 

(e) Fittings in sizes 6 in. (150 mm) and larger shall not be 
used unless approved by the authority having 
jurisdiction. 

(6) Aluminum Alloy Fittings. Threads shall not form the joint 
seal. 

(7) Zinc-Aluminum Alloy Fittings. Fittings shall not be used in 
systems containing flammable gas-air mixtures. 

(8) Special Fittings. Fittings such as couplings, proprietary-type 
joints, saddle tees, gland-type compression fittings, and 
flared, flareless, or compression-type tubing fittings shall 
be (1) used within the fitting manufacturers' pressure- 
temperature recommendations; (2) used within the ser- 
vice conditions anticipated with respect to vibration, fa- 
tigue, thermal expansion, or contraction; (3) installed or 
braced to prevent separation of the joint by gas pressure 
or external physical damage; and (4) acceptable to the 
authority having jurisdiction. 

5.6.9 Plastic Piping, Joints, and Fittings. Plastic pipe, tubing, 
and fittings shall be joined in accordance with the manufac- 
turers' instructions. The following shall be observed when 
making such joints: 

(1) The joint shall be designed and installed so that the lon- 
gitudinal pullout resistance of the joint will be at least 
equal to the tensile strength of the plastic piping material. 



2002 Edition 



ANSIZ223.1-19 



GAS PIPING SYSTEM DESIGN, MATERIALS, AND COMPONENTS 



54-19 



(2) Heat-fusion joints shall be made in accordance with quali- 
fied procedures that have been established and proven by 
test to produce gastightjoints at least as strong as the pipe 
or tubing beingjoined. Joints shall be made with the join- 
ing method recommended by the pipe manufacturer. 
Heat fusion fittings shall be marked "ASTM D 2513." 

(3) Where compression-type mechanical joints are used, the 
gasket material in the fitting shall be compatible with the 
plastic piping and with the gas distributed by the system. 
An internal tubular rigid stiffener shall be used in con- 
junction with the fitting. The stiffener shall be flush with 
the end of the pipe or tubing and shall extend at least to 
the outside end of the pipe or tubing and shall extend at 
least to the outside end of the compression fitting when 
installed. The stiffener shall be free of rough or sharp 
edges and shall not be a force fit in the plastic. Split tubu- 
lar stiffeners shall not be used. 

(4) Plastic pipingjoints and fittings for use in liquefied petro- 
leum gas piping systems shall be in accordance with 
NFPA 58, Liquefied Petroleum Gas Code. 

5.6.10 Ranges. All flanges shall comply with ANSI/ASME 
B16.1, Cast Iron Pipe Flanges and Flanged Fittings, Class 25, 125, 
250, and 800; ANSI/ASME B16.20, Metal Gaskets for Pipe 
Ranges, Ring Joint Spiral Wound and Jacketed; or MSS SP-6, Stan- 
dard Finishes for Contact Faces of Pipe Flanges and Connecting-End 
Flanges of Valves and Fittings. The pressure-temperature ratings 
shall equal or exceed that required by the application. 

5.6.10.1 Flange Facings. Standard facings shall be permitted 
foruseunder this code. Where 150 psi (1034 kPa) steel flanges 
are bolted to Class 125 cast-iron flanges, the raised face on the 
steel flange shall be removed. 

5.6.10.2 Lapped Flanges. Lapped flanges shall be used only 
aboveground or in exposed locations accessible for inspec- 
tion. 

5.6.11 Flange Gaskets. The material for gaskets shall be ca- 
pable of withstanding the design temperature and pressure of 
the piping system and the chemical constituents of the gas 
being conducted without change to its chemical and physical 
properties. The effects of fire exposure to the joint shall be 
considered in choosing the material. 

5.6.11.1 Acceptable materials shall include the following: 

(1) Metal or metal^acketed asbestos (plain or corrugated) 

(2) Asbestos 

(3) Aluminum "O" rings and spiral-wound metal gaskets 

5.6.11.2 When a flanged joint is opened, the gasket shall be 
replaced. 

5.6.11.3 Full-face gaskets shall be used with all bronze and 
cast-iron flanges. 

5.7* Gas Meters. 

5.7.1 Capacity. Gas meters shall be selected for the maximum 
expected pressure and permissible pressure drop. 

5.7.2 Location. 

5.7.2.1 Gas meters shall be located in ventilated spaces 
readily accessible for examination, reading, replacement, or 
necessary maintenance. 

5.7.2.2 Gas meters shall not be placed where they will be 
subjected to damage, such as adjacent to a driveway, under a 



fire escape, in public passages, halls, or coal bins, or where 
they will be subject to excessive corrosion or vibration. 

5.7.2.3 Gas meters shall be located at least 3 ft (0.9 m) from 
sources of ignition. 

5.7.2.4 Gas meters shall not be located where they will be 
subjected to extreme temperatures or sudden extreme 
changes in temperature. Meters shall not be located in areas 
where they are subjected to temperatures beyond those rec- 
ommended by the manufacturer. 

5.7.3 Supports. Gas meters shall be supported or connected 
to rigid piping so as not to exert a strain on the meters. Where 
flexible connectors are used to connect a gas meter to down- 
stream piping at mobile homes in mobile home parks, the 
meter shall be supported by a post or bracket placed in a firm 
footing or by other means providing equivalent support. 

5.7.4 Meter Protection. Meters shall be protected against 
overpressure, back pressure, and vacuum, where such condi- 
tions are anticipated. 

5.7.5 Identification. Gas piping at multiple meter installa- 
tions shall be marked by a metal tag or other permanent 
means attached by the installing agency, designating the build- 
ing or the part of the building being supplied. 

5.8* Gas Pressure Regulators. 

5.8.1 Where Required. A line gas pressure regulator or gas 
equipment pressure regulator, as applicable, shall be installed 
where the gas supply pressure is higher than that at which the 
branch supply line or gas utilization equipment is designed to 
operate or varies beyond design pressure limits. 

5.8.2 Line gas pressure regulators shall be listed in accor- 
dance with ANSI Z21.80, Line Pressure Regulators. 

5.8.3 Location. The gas pressure regulator shall be accessible 
for servicing. 

5.8.4 Regulator Protection. Pressure regulators shall be pro- 
tected against physical damage. 

5.8.5 Venting. 

5.8.5.1 Line Gas Pressure Regulators. Line gas pressure regu- 
lators shall comply with the following: 

(1) An independent vent to the outside of the building, sized 
in accordance with the regulator manufacturer's instruc- 
tions, shall be provided where the location of a regulator 
is such that a ruptured diaphragm will cause a hazard. 
Where there is more than one regulator at a location, 
each regulator shall have a separate vent to the outside, or 
if approved by the authority having jurisdiction, the vent 
lines shall be permitted to be manifolded in accordance 
with accepted engineering practices to minimize back 
pressure in the event of diaphragm failure. (See 5.9.7 for 
information on properly locating the vent.) Materials for 
vent piping shall be in accordance with Section 5.6. 

Exception: A regulator and vent limiting means combination listed 
as complying with ANSI Z2L80, Line Pressure Regulators, shall be 
permitted to be used without a vent to the outdoors. 

(2) The vent shall be designed to prevent the entry of water, 
insects, or other foreign materials that could cause blockage. 

(3) At locations where regulators might be submerged during 
floods, a special antiflood-type breather vent fitting shall 



2002 Edition 



54-20 



NATIONAL FUEL GAS CODE 



ANSI Z223. 1-20 



be installed, or the vent line shall be extended above the 
height of the expected flood waters. 
(4) A regulator shall not be vented to the gas equipment flue 
or exhaust system. 

5.8.5.2 Gas Appliance Pressure Regulators. For venting of gas 
appliance pressure regulators, see 8.1.19. 

5.8.6 Bypass Piping. Valved and regulated bypasses shall be 
permitted to be placed around gas line pressure regulators 
where continuity of service is imperative. 

5.8.7 Identification. Line pressure regulators at multiple 
regulator installations shall be marked by a metal tag or other 
permanent means designating the building or the part of the 
building being supplied. 

5.9 Overpressure Protection Devices. 

5.9.1 General. Overpressure protection devices shall be pro- 
vided to prevent the pressure in the piping system from ex- 
ceeding that value that would cause unsafe operation of any 
connected and properly adjusted gas utilization equipment. 

(See 5.9.5.) 

5.9.1.1 The requirements of this section shall be met and a 
piping system deemed to have overpressure protection where 
all of the following are included in the piping system: 

(1) Two devices (a service or line pressure regulator plus one 
other device) are installed. 

(2) Each device limits the pressure to a value that does not 
exceed the maximum working pressure of the down- 
stream system. 

(3) The failure of both devices occurs simultaneously in or- 
der to overpressure the downstream system. 

5.9.1.2 The pressure regulating, limiting, and relieving de- 
vices shall be properly maintained, and inspection procedures 
shall be devised or suitable instrumentation installed to detect 
failures or malfunctions of such devices, and replacements or 
repairs shall be promptiy made. 

5.9.1.3 A pressure relieving or limiting device shall not be 
required where (1) the gas does not contain materials that 
could seriously interfere with the operation of the service or 
line pressure regulator; (2) the operating pressure of the gas 
source is 60 psi (414 kPa) or less; and (3) the service or line 
pressure regulator has all of the following design features or 
characteristics: 

(1) Pipe connections to the service or line regulator do not 
exceed 2-in. nominal diameter. 

(2) It is self-contained with no external static or control pip- 
ing. 

(3) It has a single port valve with an orifice diameter no 
greater than that recommended by the manufacturer for 
the maximum gas pressure at the regulator inlet. 

(4) The valve seat is made of resilient material designed to 
withstand abrasion of the gas, impurities in the gas, and 
cutting by the valve and to resist permanent deformation 
where it is pressed against the valve port. 

(5) It is capable, under normal operating conditions, of regu- 
lating the downstream pressure within the necessary lim- 
its of accuracy and of limiting the discharge pressure un- 
der no-flow conditions to not more than 150 percent of 
the discharge pressure maintained under flow conditions. 

5.9.2 Devices. 

5.9.2. 1 Pressure relieving or pressure limiting devices shall be 
one of the following: 



(1) Spring-loaded relief device 

(2) Pilot-loaded back pressure regulator used as a relief valve 
so designed that failure of the pilot system or external 
control piping will cause the regulator relief valve to open 

(3) A monitoring regulator installed in series with the service 
or line pressure regulator 

(4) A series regulator installed upstream from the service or 
line regulator and set to continuously limit the pressure 
on the inlet of the service or line regulator to the maxi- 
mum working pressure of the downstream piping system 

(5) An automatic shutoff device installed in series with the 
service or line pressure regulator and set to shut off when 
the pressure on the downstream piping system reaches 
the maximum working pressure or some other predeter- 
mined pressure less than the maximum working pressure 
This device shall be designed so that it will remain closed 
until manually reset. 

(6) A liquid seal relief device that can be set to open accu- 
rately and consistently at the desired pressure 

5.9.2.2 The devices in 5.9.2.1 shall be installed either as an 
integral part of the service or line pressure regulator or as 
separate units. Where separate pressure relieving or pressure 
limiting devices are installed, they shall comply with 5.9.3 
through 5.9.8. 

5.9.3 Construction and Installation. All pressure relieving or 
pressure limiting devices shall meet the following requirements: 

(1) Be constructed of materials so that the operation of the 
device will not be impaired by corrosion of external parts 
by the atmosphere or of internal parts by the gas. 

(2) Be designed and installed so they can be operated to de- 
termine whether the valve is free. The devices shall also be 
designed and installed so they can be tested to determine 
the pressure at which they will operate and be examined 
for leakage when in the closed position. 

5.9.4 External Control Piping. External control piping shall 
be protected from falling objects, excavations, or other causes 
of damage and shall be designed and installed so that damage 
to any control piping shall not render both the regulator and 
the overpressure protective device inoperative. 

5.9.5 Setting. Each pressure limiting or pressure relieving de- 
vice shall be set so that the pressure shall not exceed a safe 
level beyond the maximum allowable working pressure for the 
piping and appliances connected. 

5.9.6 Unauthorized Operation. Precautions shall be taken to 
prevent unauthorized operation of any shutoff valve that wiW 
make a pressure relieving valve or pressure limiting device in- 
operative. The following are acceptable methods for comply- 
ing with this provision: 

(1) Lock the valve in the open position. Instruct authorized 
personnel in the importance of leaving the shutoff valve 
open and of being present while the shutoff valve is closed 
so that it can be locked in the open position before leav- 
ing the premises. 

(2) Install duplicate relief valves, each having adequate capac- 
ity to protect the system, and arrange the isolating valves 
or three-way valve so that only one safety device can be 
rendered inoperative at a time. 

5.9.7 Vents. The discharge stacks, vents, or outlet parts of all 
pressure relieving and pressure limiting devices shall be lo- 
cated so that gas is safely discharged into the outside atmo- 



2002 Edition 



ANSI Z223. 1-21 



GAS PIPING INSTALLATION 



54-21 



sphere. Discharge stacks or vents shall be designed to prevent the 
entry of water, insects, or other foreign material that could cause 
blockage. The discharge stack or vent line shall be at least the 
same size as the oudet of the pressure relieving device. 

5.9.8 Size of Fittings, Pipe, and Openings. The fittings, pipe, 
and openings located between the system to be protected and 
the pressure relieving device shall be sized to prevent hammering 
of the valve and to prevent impairment of relief capacity. 

5.10 Back Pressure Protection. 

5.10.1 Where to Install. Protective devices shall be installed as 
close to the utilization equipment as practical where the de- 
sign of utilization equipment connected is such that air, oxy- 
gen, or standby gases could be forced into the gas supply sys- 
tem. Gas and air combustion mixers incorporating double 
diaphragm "zero" or "atmosphere" governors or regulators 
shall require no further protection unless connected directly 
to compressed air or oxygen at pressures of 5 psi (34 kPa) or 
more. 

5.10.2 Protective Devices. Protective devices shall include but 
not be limited to the following: 

(1) Check valves 

(2) Three-way valves (of the type that completely closes one 
side before starting to open the other side) 

(3) Reverse flow indicators controlling positive shu toff valves 

(4) Normally closed air-actuated positive shutoflf pressure 
regulators 

5.11 Low-Pressure Protection. A protective device shall be in- 
stalled between the meter and the gas utilization equipment if 
the operation of the equipment is such (i.e., gas compressors) 
that it could produce a vacuum or a dangerous reduction in 
gas pressure at the meter; such devices include, but are not 
limited to, mechanical, diaphragm-operated, or electrically 
operated low-pressure shutoff valves. 

5.12 Shutoff Valves. Shutoff valves shall be approved and shall 
be selected giving consideration to pressure drop, service in- 
volved, emergency use, and reliability of operation. Shutoff 
valves of size 1 in. National Pipe Thread and smaller shall be 
listed. 

5.13 Expansion and Flexibility. 

5.13.1 Design. Piping systems shall be designed to have suffi- 
cient flexibility to prevent thermal expansion or contraction 
from causing excessive stresses in the piping material, exces- 
sive bending or loads at joints, or undesirable forces or mo- 
ments at points of connections to equipment and at anchor- 
age or guide points. Formal calculations or model tests shall 
be required only where reasonable doubt exists as to the ad- 
equate flexibility of the system. 

5.13.1.1 Flexibility shall be provided by the use of bends, 
loops, offsets, or couplings of the slip type. Provision shall be 
made to absorb thermal changes by the use of expansion 
joints of the bellows type or by the use of "ball" or "swivel" 
joints. Expansion joints of the slip type shall not be used inside 
buildings or for thermal expansion. Where expansion joints 
are used, anchors or ties of sufficient strength and rigidity 
shall be installed to provide for end forces due to fluid pres- 
sure and other causes. 

5.13.1.2 Pipe alignment guides shall be used with expansion 
joints according to the recommended practice of the joint 
manufacturer. 



5.13.2 Special Local Conditions. Where local conditions in- 
clude earthquake, tornado, unstable ground, or flood haz- 
ards, special consideration shall be given to increased strength 
and flexibility of piping supports and connections. 



Chapter 6 Gas Piping Installation 

6.1 Piping Underground. 

6.1.1 Clearances. Underground gas piping shall be installed 
with sufficient clearance from any other underground struc- 
ture to avoid contact therewith, to allow maintenance, and to 
protect against damage from proximity to other structures. In 
addition, underground plastic piping shall be installed with 
sufficient clearance or shall be insulated from any source of 
heat so as to prevent the heat from impairing the serviceability 
of the pipe. 

6.1.2 Protection Against Damage. Means shall be provided to 
prevent excessive stressing of the piping where there is heavy 
vehicular traffic or soil conditions are unstable and settling 
of piping or foundation walls could occur. Piping shall be 
buried or covered in a manner so as to protect the piping 
from physical damage. Piping shall be protected from 
physical damage where it passes through flower beds, shrub 
beds, and other such cultivated areas where such damage is 
reasonably expected. 

6.1.2.1 Cover Requirements. Underground piping systems 
shall be installed with a minimum of 18 in. (460 mm) of cover. 
Where external damage to the pipe is not likely to result, the 
minimum cover shall be 12 in. (300 mm). Where a minimum 
of 12 in. (300 mm) of cover cannot be provided, the pipe shall 
be installed in conduit or bridged (shielded). 

6.1.2.2 Trenches. The trench shall be graded so that the pipe 
has a firm, substantially continuous bearing on the bottom of 
the trench. 

6.1.2.3 BacktiUing. Where flooding of the trench is done to 
consolidate the backfill, care shall be exercised to see that the 
pipe is not floated from its firm bearing on the trench bottom. 

6.1.3* Protection Against Corrosion. Gas piping in contact 
with earth or other material that could corrode the piping 
shall be protected against corrosion in an approved manner. 
When dissimilar mietals are joined underground, an insulating 
coupling or fitting shall be used. Piping shall not be laid in 
contact with cinders. Uncoated threaded or socket welded 
joints shall not be used in piping in contact with soil or where 
internal or external crevice corrosion is known to occur. 

6.1.4* Protection Against Freezing. Where the formation of 
hydrates or ice is known to occur, piping shall be protected 
against freezing. 

6.1.5 Piping Through Foundation Wall. Underground piping, 
where installed through the outer foundation or basement 
wall of a building, shall be encased in a protective pipe. The 
space between the gas piping and the building shall be sealed 
to prevent entry of gas or water. 

6.1.6 Piping Underground Beneath Buildings. Where the in- 
stallation of gas piping underground beneath buildings is un- 
avoidable, the piping shall be encased in an approved conduit 
designed to withstand the superimposed loads. The conduit 
shall extend into a normally usable and accessible portion of 
the building and, at the point where the conduit terminates in 



2002 Edition 



54-22 



NATIONAL FUEL GAS CODE 



ANSI Z223. 1-22 



the building, the space between the conduit and the gas pip- 
ing shall be sealed to prevent the possible entrance of any gas 
leakage. Where the end sealing is of a type that will retain the 
full pressure of the pipe, the conduit shall be designed for the 
same pressure as the pipe. The conduit shall extend at least 
4 in. (100 mm) outside the building, be vented above grade to 
the outside, and be installed so as to prevent the entrance of 
water and insects. 

6.1.7 Plastic Pipe. 

6.1.7.1 Connection of Plastic Piping. Plastic pipe shall be in- 
stalled outside, underground only. 

Exception No. 1: Plastic pipe shall be permitted to terminate above- 
ground where an anodeless riser is used. 

Exception No. 2: Plastic pipe shall be permitted to terminate with a 
wall head adapter aboveground in buildings, including basements, 
where the plastic pipe is inserted in a piping material permitted for use 
in buildings. 

6.1.7.2 Connections Between Metallic and Plastic Piping. 

Connections made outside and underground between metal- 
lic and plastic piping shall be made only with ASTM D 2513, 
Standard Specification for Thermoplastic Gas Pressure Pipe, Tubing, 
and Fittings, Category I transition fittings. 

6.1.7.3 Tracer Wire. An electrically continuous corrosion- 
resistant tracer wire (minimum AWG 14) or tape shall be bur- 
ied with the plastic pipe to facilitate locating. One end shall be 
brought aboveground at a building wall or riser. 

6.2 Installation of Piping. 

6.2.1 Piping installed aboveground shall be securely sup- 
ported and located where it will be protected from physical 
damage (also see 6.1.4). Where passing through an outside wall, 
the piping shall also be protected against corrosion by coating 
or wrapping with an inert material approved for such applica- 
tions. Where piping is encased in a protective pipe sleeve, the 
annular space between the gas piping and the sleeve shall be 
sealed at the wall to prevent the entry of water, insects, or 
rodents. 

6.2.2 Building Structure. 

6.2.2.1 The installation of gas piping shall not cause struc- 
tural stresses within building components to exceed allowable 
design limits. 

6.2.2.2 Approval shall be obtained before any beams or joists 
are cut or notched. 

6.2.3 Other than Dry Gas. Drips, sloping, protection from 
freezing, and branch pipe connections, as provided for in 
6.1.4, 6.6.1, and Section 6.8, shall be provided when other 
than dry gas is distributed and climatic conditions make such 
provisions necessary. 

6.2.4 Gas Piping to Be Sloped. Piping for other than dry gas 
conditions shall be sloped not less than V4 in. in 15 ft (7 mm in 
4.6 m) to prevent traps. 

6.2.5* Prohibited Locations. Gas piping inside any building 
shall not be installed in or through a clothes chute, chimney 
or gas vent, dumbwaiter, elevator shaft, or air duct, other than 
combustion air ducts. 

6.2.6 Hangers, Supports, and Anchors. 

6.2.6.1 Piping shall be supported with pipe hooks, metal pipe 
straps, bands, brackets, or hangers suitable for the size of pip- 



ing, of adequate strength and quality, and located at intervals 
so as to prevent or damp out excessive vibration. Piping shall 
be anchored to prevent undue strains on connected equip- 
ment and shall not be supported by other piping. Pipe hang- 
ers and supports shall conform to the requirements of ANSI/ 
MSS SP-58, Pipe Hangers and Supports — Materials, Design and 
Manufacture. 

6.2.6.2 Spacings of supports in gas piping installations shall 
not be greater than shown in Table 6.2.6.2. Spacing of sup- 
ports of CSST shall be in accordance with the CSST manufac- 
turer's instructions. 



Table 6.2.6.2 Support of Piping 



Steel Pipe, 

Nominal 

Size of Pipe 

(in.) 


Spacing of 
Supports 

(ft) 


Nominal 

Size of 

Tubing 

Smooth-WaU 

(in. O.D.) 


Spacing of 
Supports 

(ft) 


1/2 

% or 1 

1 V4 or larger 

(horizontal) 

1 Va or larger 

(vertical) 


6 
8 
10 

every floor 
level 


1/2 

ys or % 

% or 1 

(horizontal) 

1 or larger 

(vertical) 


4 
6 
8 

every floor 
level 



For SI units, 1 ft = 0.305 m. 



6.2.6.3 Supports, hangers, and anchors shall be installed so 
as not to interfere with the free expansion and contraction of 
the piping between anchors. All parts of the supporting equip- 
ment shall be designed and installed so they will not be disen- 
gaged by movement of the supported piping. 

6.2.7 Removal of Pipe. Where piping containing gas is to be 
removed, the line shall be first disconnected from all sources 
of gas and then thoroughly purged vsdth air, water, or inert gas 
before any cutting or welding is done. (See Section 7.3.) 

6.3 Concealed Piping in Buildings. 

6.3.1 General. Gas piping in concealed locations shall be in- 
stalled in accordance v^th this section. 

6.3.2 Connections. Where gas piping is to be concealed, 
unions, tubing fittings, right and left couplings, bushings, 
swing joints, and compression couplings made by combina- 
tions of fittings shall not be used. Connections shall be of the 
following type: 

(1) Pipe fittings such as elbows, tees, and couplings 

(2) Joining tubing by brazing [see 5.6.8.2] 

(3) Fittings listed for use in concealed spaces that have been 
demonstrated to sustain, without leakage, any forces due 
to temperature expansion or contraction, vibration, or 
fatigue based on their geographic location, application, 
or operation. 

(4) Where necessary to insert fittings in gas pipe that has been 
installed in a concealed location, the pipe shall be recon- 
nected by welding, flanges, or the use of a ground joint 
union with the nut center-punched to prevent loosening 
by vibration. 

6.3.3 Piping in Partitions. Concealed gas piping shall not be 
located in solid partitions. 



2002 Edition 



ANSI Z223. 1-23 



GAS PIPING INSTALLATION 



54-23 



6.3.4 Tubing in Partitions. This provision shall not apply to 
tubing that pierces walls, floors, or partitions. Tubing installed 
vertically and horizontally inside hollow walls or partitions 
without protection along its entire concealed length shall 
meet the following requirements: 

(1) A steel striker barrier not less than 0.0508 in. (1.3 mm) 
thick, or equivalent, is installed between the tubing and 
the finished wall and extends at least 4 in. (100 mm) be- 
yond concealed penetrations of plates, fire stops, wall 
studs, and so on. 

(2) The tubing is installed in single runs and is not rigidly 
secured. 

6.3.5 Piping in Floors. 

6.3.5.1 Industrial Occupancies. In industrial occupancies, 
gas piping in solid floors such as concrete shall be laid in 
channels in the floor and covered to permit access to the 
piping with a minimum of damage to the building. Where 
piping in floor channels could be exposed to excessive 
moisture or corrosive substances, the piping shall be pro- 
tected in an approved manner. 

6.3.5.2 Other Occupancies. In other than industrial occupan- 
cies and where approved by the authority having jurisdiction, 
gas piping embedded in concrete floor slabs constructed with 
pordand cement shall be surrounded with a minimum ofVA in. 
(38 mm) of concrete and shall not be in physical contact with 
other metallic structures such as reinforcing rods or electrically 
neutral conductors. All piping, fittings, and risers shall be pro- 
tected against corrosion in accordance with 5.6.6. Piping shall 
not be embedded in concrete slabs containing quickset additives 
or cinder aggregate. 

6.4 Piping in Vertical Chases. Where gas piping exceeding 5 psi 
(34 kPa) is located within vertical chases in accordance with 
5.5.1(2) , the requirements of 6.4.1 through 6.4.3 shall apply. 

6.4.1 Pressure Reduction. Where pressure reduction is re- 
quired in branch connections for compliance v^th 5.5.1, such 
reduction shall take place either inside the chase or immedi- 
ately adjacent to the outside wall of the chase. Regulator vent- 
ing and downstream overpressure protection shall comply 
with 5.8.5 and Section 5.9. The regulator shall be accessible 
for service and repair and vented in accordance with one of 
the following: 

(1) Where the fuel gas is lighter than air, regulators equipped 
with a vent-limiting means shall be permitted to be vented 
into the chase. Regulators not equipped with a vent-limiting 
means shall be permitted to be vented either directiy to the 
outdoors or to a point within the top 1 ft (0.3 m) of the 
chase. 

(2) Where the fuel gas is heavier than air, the regulator vent 
shall be vented only directly to the outdoors. 

6.4.2 Chase Construction. Chase construction shall comply 
with local building codes with respect to fire resistance and 
protection of horizontal and vertical openings. 

6.4.3* Ventilation. A chase shall be ventilated to the outdoors 
and only at the top. The opening(s) shall have a minimum 
free area (in square inches) equal to the product of one-half 
of the maximum pressure in the piping (in psi) times the larg- 
est nominal diameter of that piping (in inches), or the cross- 
sectional area of the chase, whichever is smaller. Where more 
than one fuel gas piping system is present, the free area for 
each system shall be calculated and the largest area used. 



6.5 Gas Pipe Turns. Changes in direction of gas pipe shall be 
made by the use of fittings, factory bends, or field bends. 

6.5.1 Metallic Pipe. Metallic pipe bends shall comply with the 
following: 

(1) Bends shall be made only with bending equipment and 
procedures intended for that purpose. 

(2) All bends shall be smooth and free from buckling, cracks, 
or other evidence of mechanical damage. 

(3) The longitudinal weld of the pipe shall be near the neu- 
tral axis of the bend. 

(4) Pipe shall not be bent through an arc of more than 90 de- 
grees. 

(5) The inside radius of a bend shall be not less than 6 times 
the outside diameter of the pipe. 

6.5.2 Plastic Pipe. Plastic pipe bends shall comply with the 
following: 

(1) The pipe shall not be damaged, and the internal diameter 
of the pipe shall not be effectively reduced. 

(2) Joints shall not be located in pipe bends. 

(3) The radius of the inner curve of such bends shall not be 
less than 25 times the inside diameter of the pipe. 

(4) Where the piping manufacturer specifies the use of spe- 
cial bending equipment or procedures, such equipment 
or procedures shall be used. 

6.5.3* Mitered Bends. Mitered bends shall be permitted sub- 
ject to the following limitations: 

(1) Miters shall not be used in systems having a design pres- 
sure greater than 50 psi (340 kPa). Deflections caused by 
misalignments up to 3 degrees shall not be considered as 
miters. 

(2) The total deflection angle at each miter shall not exceed 
90 degrees. 

6.5.4 Elbows. Factory-made welding elbows or transverse seg- 
ments cut therefrom shall have an arc length measured along 
the crotch of at least 1 in. (25 mm) for pipe sizes 2 in. and 
larger. 

6.6 Drips and Sediment Traps. 

6.6.1 Provide Drips Where Necessary. For other than dry gas 
conditions, a drip shall be provided at any point in the line of 
pipe where condensate could collect. Where required by the 
authority havingjurisdiction or the serving gas supplier, a drip 
shall also be provided at the outlet of the meter. This drip shall 
be so installed as to constitute a trap wherein an accumulation 
of condensate will shut off the flow of gas before it will run 
back into the meter. 

6.6.2 Location of Drips. All drips shall be installed only in 
such locations that they will be readily accessible to permit 
cleaning or emptying. A drip shall not be located where the 
condensate is likely to freeze. 

6.6.3 Sediment Traps. (See 8.5.7.) 

6.7 Outlets. 

6.7.1 Location and Installation. 

6.7.1.1 The outlet fittings or piping shall be securely fastened 
in place. 

6.7.1.2 Oudets shall not be located behind doors. 



2002 Edition 



54-24 



NATIONAL FUEL GAS CODE 



ANSI Z223.1-24 



6.7.1.3 Outlets shall be located far enough from floors, walls, 
patios, slabs, and ceilings to permit the use of wrenches with- 
out straining, bending, or damaging the piping. 

6.7.1.4 The unthreaded portion of gas piping outlets shall 
extend not less than 1 in. (25 mm) through finished ceilings 
or indoor or outdoor walls. 

6.7.1.5 The unthreaded portion of gas piping outlets shall 
extend not less than 2 in. (50 mm) above the surface of floors 
or outdoor patios or slabs. 

6.7.1.6 The provisions of 6.7.1.4 and 6.7.1.5 shall not apply to 
listed quick-disconnect devices of the flush-mounted type or 
listed gas convenience outlets. Such devices shall be installed in 
accordance with the manufacturers' installation instructions. 

6.7.2 Cap All Outlets. 

6.7.2.1 Each outlet, including a valve, shall be closed gastight 
with a threaded plug or cap immediately after installation and 
shall be left closed until the gas utilization equipment is con- 
nected thereto. When equipment is disconnected from an 
outlet and the outlet is not to be used again immediately, it 
shall be closed gastight. 

Exception No. 1: Laboratory equipment installed in accordance with 
8.5.2(1) shall be permitted. 

Exception No. 2: The use of a listed quick-disconnect device with 
integral shutoffor listed gas convenience outlet shall be permitted. 

6.7.2.2 Equipment shutoff valves installed in fireplaces shall 
be removed and the piping capped gastight where the fire- 
place is used for solid fuel burning. 

6.8 Branch Pipe Connection. When a branch outlet is placed 
on a main supply line before it is known what size pipe will be 
connected to it, the outlet shall be of the same size as the line 
that supplies it. 

6.9 Manual Gas Shutoff Valves. (Also see 8.5.4.) 

6.9.1 Valves at Regulators. An accessible gas shutoff valve shall 
be provided upstream of each gas pressure regulator. Where 
two gas pressure regulators are installed in series in a single 
gas line, a manual valve shall not be required at the second 
regulator. 

6.9.2 Valves Controlling Multiple Systems. 

6.9.2.1 Accessibility of Gas Valves. Main gas shutoff valves 
controlling several gas piping systems shall be readily acces- 
sible for operation and installed so as to be protected from 
physical damage. They shall be marked with a metal tag or 
other permanent means attached by the installing agency so 
that the gas piping systems supplied through them can be 
readily identified. 

6.9.2.2 Shutoff Valves for Multiple House Lines. In multiple 
tenant buildings supplied through a master meter, or through 
one service regulator where a meter is not provided, or where 
meters or service regulators are not readily accessible from the 
equipment location, an individual shutoff valve for each apart- 
ment or tenant line shall be provided at a convenient point of 
general accessibility. In a common system serving a number of 
individual buildings, shutoff valves shall be installed at each 
building. 

6.9.3 Emergency Shutoff Valves. An exterior shutoff valve to 
permit turning off the gas supply to each building in an emer- 
gency shall be provided. The emergency shutoff valves shall be 



plainly marked as such and their locations posted as required 
by the authority having jurisdiction. 

6.10 Prohibited Devices. No device shall be placed inside 
the gas piping or fittings that will reduce the cross-sectional 
area or otherwise obstruct the free flow of gas, except where 
proper allowance in the piping system design has been 
made for such a device and where approved by the author- 
ity having jurisdiction. 

6.11 Systems Containing Gas-Air Mixtures Outside the Flam- 
mable Range. Where gas-air mixing machines are employed 
to produce mixtures above or below the flammable range, 
they shall be provided with stops to prevent adjustment of the 
mixture to within or approaching the flammable range. 

6.12 Systems Containing Flanmiable Gas-Air Mixtures. 

6.12.1 Required Components. A central premix system with a 
flammable mixture in the blower or compressor shall consist 
of the foUovwng components: 

(1) Gas-mixing machine in the form of an automatic gas-air 
proportioning device combined with a downstream 
blower or compressor 

(2) Flammable mixture piping, minimum Schedule 40 NFS 

(3) Automatic firecheck(s) 

(4) Safety blowout(s) or backfire preventers for systems utiliz- 
ing flammable mixture lines above 2V2 in. nominal pipe 
size or the equivalent 

6.12.2 Optional Components. The following components 
shall also be permitted to be utilized in any type central pre- 
mix system: 

(1) Flowmeter (s) 

(2) Flame arrester(s) 

6.12.3 Additional Requirements. Gas-mixing machines shall 
have nonsparking blowers and shall be so constructed that a 
flashback will not rupture machine casings. 

6.12.4* Special Requirements for Mixing Blowers. A mixing 
blower system shall be limited to applications with minimum 
practical lengths of mixture piping, limited to a maximum 
mixture pressure of 10 in. w.c. (2.5 kPa) and limited to gases 
containing no more than 10 percent hydrogen. The blower 
shall be equipped with a gas-control valve at its air entrance so 
arranged that gas is admitted to the airstream, entering the 
blower in proper proportions for correct combustion by the 
type of burners employed, the said gas-control valve being of 
either the zero governor or mechanical ratio valve type that 
controls the gas and air adjustment simultaneously. No valves 
or other obstructions shall be installed between the blower 
discharge and the burner or burners. 

6.12.5 Installation of Gas-Mixing Machines. 

6.12.5.1* Location. The machine shall be located in a large, 
well-ventilated area or in a small detached building or cut- 
off room provided with room construction and explosion 
vents in accordance with sound engineering principles. 
Such rooms or belowgrade installations shall have adequate 
positive ventilation. 

6.12.5.2 Electrical Requirements. Where gas-mixing ma- 
chines are installed in well-ventilated areas, the type of electri- 
cal equipment shall be in accordance with NFPA 70, National 
Electrical Code®, for general service conditions unless other 
hazards in the area prevail. Where gas-mixing machines are 
installed in small detached buildings or cutoff rooms, the elec- 



2002 Edition 



ANSI Z223.1-25 



INSPECTION, TESTING, AND PURGING 



54-25 



trical equipment and wiring shall be installed in accordance 
with NFPA 70 for hazardous locations (Articles 500 and 501, 
Class I, Division 2). 

6.12.5.3 Air Intakes. Air intakes for gas-mixing machines us- 
ing compressors or blowers shall be taken from outdoors 
whenever practical. 

6.12.5.4* Controls. Controls for gas-mixing machines shall in- 
clude interlocks and a safety shutoif valve of the manual reset 
type in the gas supply connection to each machine arranged 
to automatically shut off the gas supply in the event of high or 
low gas pressure. Except for open burner installations only, 
the controls shall be interlocked so that the blower or com- 
pressor will stop operating following a gas supply failure. 
Where a system employs pressurized air, means shall be pro- 
vided to shut off the gas supply in the event of air failure. 

6.12.5.5 Installation in Parallel. Centrifugal gas-mixing ma- 
chines in parallel shall be reviewed by the user and equipment 
manufacturer before installation, and means or plans for 
minimizing these effects of downstream pulsation and equip- 
ment overload shall be prepared and utilized as needed. 

6.12.6 Use of Automatic Firechecks, Safety Blowouts, or 
Backfire Preventers. Automatic firechecks and safety blowouts 
or backfire preventers shall be provided in piping systems dis- 
tributing flammable air-gas mixtures from gas-mixing ma- 
chines to protect the piping and the machines in the event of 
flashback, in accordance with the follov«ng: 

(l)*Approved automatic firechecks shall be installed up- 
stream as close as practicable to the burner inlets follow- 
ing the firecheck manufacturers' instructions. 

(2) A separate manually operated gas valve shall be provided 
at each automatic firecheck for shutting off the flow of 
gas-air mixture through the firecheck after a flashback 
has occurred. The valve shall be located upstream as close 
as practical to the inlet of the automatic firecheck. Cau- 
tion, these valves shall not be reopened after a flashback 
has occurred until the firecheck has cooled sufficiently to 
prevent reignition of the flammable mixture and has 
been reset properly. 

(3) Asafety blowout or backfiring preventer shall be provided 
in the mixture line near the outlet of each gas-mixing 
machine where the size of the piping is larger than 2V^ in. 
NFS, or equivalent, to protect the mixing equipment in 
the event of an explosion passing through an automatic 
firecheck. The manufacturers' instructions shall be fol- 
lowed when installing these devices, particularly after a 
disc has burst. The discharge from the safety blowout or 
backfire preventer shall be located or shielded so that par- 
ticles from the ruptured disc cannot be directed toward per- 
sonnel. Wherever there are interconnected installations of 
gas-mixing machines with safety blowouts or backfire pre- 
venters, provision shall be made to keep the mixture from 
other machines from reaching any ruptured disc opening. 
Check valves shall not be used for this purpose. 

(4) Large-capacity premix systems provided with explosion 
heads (rupture disc) to relieve excessive pressure in pipe- 
lines shall be located at and vented to a safe outdoor loca- 
tion. Provisions shall be provided for automatically shut- 
ting off the supply of the gas-air mixture in the event of 
rupture. 

6.13 Electrical Bonding and Grounding. 

6.13.1 Each aboveground portion of a gas piping system that 
is likely to become energized shall be electrically continuous 



and bonded to an effective ground-fault current path. Gas pip- 
ing shall be considered to be bonded when it is connected to 
gas utilization equipment that is connected to the equipment 
grounding conductor of the circuit supplying that equipment. 

6.13.2 Gas piping shall not be used as a grounding conductor 
or electrode. 

6.14 Electrical Circuits. Electrical circuits shall not utilize gas 
piping or components as conductors. 

Exception: Low-voltage (50 V or less) control circuits, ignition cir- 
cuits, and electronic flame detection device circuits shall be permitted to 
make use of piping or components as a part of an electric circuit. 

6.15 Electrical Connections. 

6.15.1 All electrical connections between wiring and electri- 
cally operated control devices in a piping system shall conform 
to the requirements of NFPA 70, National Electrical Code. (See 
Section 6.13.) 

6.15.2 Any essential safety control depending on electric cur- 
rent as the operating medium shall be of a type that will shut 
off (fail safe) the flow of gas in the event of current failure. 



Chapter 7 Inspection, Testing, and Putting 

7.1 Pressure Testing and Inspection. 
7.1.1* General. 

7.1.1.1 Prior to acceptance and initial operation, all piping 
installations shall be inspected and pressure tested to deter- 
mine that the materials, design, fabrication, and installation 
practices comply with the requirements of this code. 

7.1.1.2 Inspection shall consist of visual examination, during 
or after manufacture, fabrication, assembly, or pressure tests 
as appropriate. Supplementary types of nondestructive inspec- 
tion techniques, such as magnetic-particle, radiographic, and 
ultrasonic, shall not be required unless specifically listed 
herein or in the engineering design. 

7.1.1.3 Where repairs or additions are made follovsdng the 
pressure test, the affected piping shall be tested. Minor repairs 
and additions are not required to be pressure tested provided 
that the work is inspected and connections are tested with a 
noncorrosive leak-detecting fluid or other leak-detecting 
methods approved by the authority having jurisdiction. 

7.1.1.4 Where new branches are installed from the point of 
delivery to new appliance (s), only the newly installed 
branch (es) shall be required to be pressure tested. Connec- 
tions between the new piping and the existing piping shall be 
tested with a noncorrosive leak-detecting fluid or approved 
leak-detecting methods. 

7.1.1.5 Apiping system shall be tested as a complete unit or in 
sections. Under no circumstances shall a valve in a line be used 
as a bulkhead between gas in one section of the piping system 
and test medium in an adjacent section, unless two valves are 
installed in series with a valved "tell tale" located between these 
valves. A valve shall not be subjected to the test pressure unless it 
can be determined that the valve, including the valve closing 
mechanism, is designed to safely withstand the pressure. 

7.1.1.6 Regulator and valve assemblies fabricated indepen- 
dently of the piping system in which they are to be installed 



2002 Edition 



54-26 



NATIONAL FUEL GAS CODE 



ANSI Z223. 1-26 



shall be permitted to be tested with inert gas or air at the time 
of fabrication. 

7.1.2 Test Medium. The test medium shall be air, nitrogen, 
carbon dioxide, or an inert gas. 

OXYGEN SHALL NEVER BE USED. 

7.1.3 Test Preparation. 

7.1.3.1 Pipe joints, including welds, shall be left exposed for 
examination during the test. 

Exception: Covered or concealed pipe end joints that have been previ- 
ously tested in accordance with this code. 

7.1.3.2 Expansion joints shall be provided with temporary re- 
straints, if required, for the additional thrust load under test. 

7.1.3.3 Appliances and equipment that are not to be in- 
cluded in the test shall be either disconnected from the piping 
or isolated by blanks, blind flanges, or caps. Flanged joints at 
which blinds are inserted to blank off other equipment during 
the test shall not be required to be tested. 

7.1.3.4 Where the piping system is connected to appliances, 
equipment, or equipment components designed for operating 
pressures of less than the test pressure, such appliances, equip- 
ment, or equipment components shall be isolated from the pip- 
ing system by disconnecting them and capping the outlet(s). 

7.1.3.5 Where the piping system is connected to appliances, 
equipment, or equipment components designed for operat- 
ing pressures equal to or greater than the test pressure, such 
appliances and equipment shall be isolated from the piping 
system by closing the individual equipment shutofF valve (s). 

7.1.3.6 All testing of piping systems shall be done with due 
regard for the safety of employees and the public during the 
test. Bulkheads, anchorage, and bracing suitably designed to 
resist test pressures shall be installed if necessary. Prior to test- 
ing, the interior of the pipe shall be cleared of all foreign 
material. 

7.1.4 Test Pressure. 

7.1.4.1 Test pressure shall be measured with a manometer or 
with a pressure measuring device designed and calibrated to 
read, record, or indicate a pressure loss due to leakage during 
the pressure test period. The source of pressure shall be iso- 
lated before the pressure tests are made. Mechanical gauges 
used to measure test pressures shall have a range such that the 
highest end of the scale is not greater than 5 times the test 
pressure. 

7.1.4.2 The test pressure to be used shall be no less than \V2 
times the proposed maximum working pressure, but not less 
than 3 psi (20 kPa), irrespective of design pressure. Where the 
test pressure exceeds 125 psi (862 kPa), the test pressure shall 
not exceed a value that produces a hoop stress in the piping 
greater than 50 percent of the specified minimum yield 
strength of the pipe. 

7.1.4.3 Test duration shall be not less than V2 hour for each 
500 ft^ (14 m^) of pipe volume or fraction thereof. When test- 
ing a system having a volume less than 10 ft^ (0.28 m^) or a 
system in a single-family dwelling, the test duration shall be a 
minimum of 10 minutes. The duration of the test shall not be 
required to exceed 24 hours. 

7.1.5 Detection of Leaks and Defects. 

7.1.5.1 The piping system shall withstand the test pressure 
specified without showing any evidence of leakage or other de- 



fects. Any reduction of test pressures as indicated by pressure 
gauges shall be deemed to indicate the presence of a leak unless 
such reduction can be readily attributed to some other cause. 

7.1.5.2 The leakage shall be located by means of an approved 
gas detector, a noncorrosive leak detection fluid, or other ap- 
proved leak detection methods. Matches, candles, open 
flames, or other methods that provide a source of ignition 
shall not be used. 

7.1.5.3 Where leakage or other defects are located, the af- 
fected portion of the piping system shall be repaired or re- 
placed and retested. (See 7.1.1.3.) 

7.2 System and Equipment Leakage Test. 

7.2.1 Test Gases. Leak checks using fuel gas shall be permit- 
ted in piping systems that have been pressure tested in accor- 
dance with Section 7.1. 

7.2.2 Before Turning Gas On. Before gas is introduced into a 
system of new gas piping, the entire system shall be inspected 
to determine that there are no open fittings or ends and that 
all valves at unused outlets are closed and plugged or capped. 

7.2.3* Test for Leakage. Immediately after the gas is turned on 
into a new system or into a system that has been initially restored 
after an interruption of service, the piping system shall be tested 
for leakage. Where leakage is indicated, the gas supply shall be 
shut off until the necessary repairs have been made. 

7.2.4 Placing Equipment in Operation. Gas utilization equip- 
ment shall not be placed in operation until after the piping 
system has been tested in accordance with 7.2.3 and purged in 
accordance with 7.3.2. 

7.3* Pui^g. 

7.3.1 Removal from Service. When gas piping is to be opened 
for an addition, a modification, or for service, the section to be 
worked on shall be turned off from the gas supply at the near- 
est convenient point and the line pressure vented to the out- 
doors or to ventilated areas of sufficient size to prevent accu- 
mulation of flammable mixtures. The remaining gas in this 
section of pipe shall be displaced with an inert gas as required 
by Table 7.3.1. 



Table 7.3.1 Length of Piping Requiring Purging with Inert 
Gas for Servicing or Modification 



Nominal 
Pipe Size 

(in.) 



Length of Piping 
Requiring Purging 

(ft) 



2^/2 

3 

4 

6 

8 or larger 



>50 
>30 
>15 
>10 
Any length 



For SI units, 1 ft = 0.305 m. 



7.3.2 Placing in Operation. When piping full of air is placed 
in operation, the air in the piping shall be displaced with fuel 
gas, except where such piping is required by Table 7.3.2 to be 
purged with an inert gas prior to introduction of fuel gas. The 
air can be safely displaced with fuel gas provided that a mod- 
erately rapid and continuous flow of fuel gas is introduced at 



2002 Edition 



ANSI Z223. 1-27 



EQUIPMENT INSTALLATION 



54-27 



one end of the line and air is vented out at the other end. The 
fuel gas flow shall be continued without interruption until the 
vented gas is free of air. The point of discharge shall not be left 
unattended during purging. After purging, the vent shall then 
be closed. Where required by Table 7.3.2, the air in the piping 
shall first be displaced with an inert gas, and the inert gas shall 
then be displaced with fuel gas. 



Table 7.3.2 Length of Piping Requiring Pui^ing with Inert 
Gas Before Being Placed in Operation 



Nominal 
Pipe Size 

(in.) 



Length of Piping 

Requiring Purging 

(ft) 



3 

4 

6 

8 or larger 



>30 

>15 

>10 

Any length 



For SI units, 1 ft = 0.305 m. 



7.3.3 Discharge of Pureed Gases. The open end of piping 
systems being purged shall not discharge into confined spaces 
or areas where there are sources of ignition unless precautions 
are taken to perform this operation in a safe manner by venti- 
lation of the space, control of purging rate, and ehminadon of 
all hazardous conditions. 

7.3.4 Placing Equipment in Operation. After the piping has 
been placed in operation, all equipment shall be purged and 
then placed in operation, as necessary. 



Chapter 8 Equipment Installation 

8.1 General. 

8.1.1* Appliances, Accessories, and Equipment to Be Ap- 
proved. Gas appliances, accessories, and gas utilization equip- 
ment shall be approved. Approved shall mean "acceptable to 
the authority having jurisdiction." Acceptance of unlisted gas 
utilization equipment and accessories shall be on the basis of a 
sound engineering evaluation. In such cases, the equipment 
shall be safe and suitable for the proposed service and shall be 
recommended for the service by the manufacturer. 

8.1.2 Added or Converted Equipment. When additional or 
replacement equipment is installed or an appliance is con- 
verted to gas from another fuel, the location in which the 
equipment is to be operated shall be checked to verify the 
following: 

(1) Air for combustion and ventilation is provided where re- 
quired, in accordance with the provisions of Section 8.3. 
Where existing facilities are not adequate, they shall be 
upgraded to meet Section 8.3 specifications. 

(2) The installation components and equipment meet the 
clearances to combustible material provisions of 8.2.2. It 
shall be determined that the installation and operation of 
the additional or replacement equipment does not ren- 
der the remaining equipment unsafe for continued op- 
eration. 

(3) The venting system is constructed and sized in accor- 
dance with the provisions of Chapter 10. Where the exist- 



ing venting system is not adequate, it shall be upgraded to 
comply with Chapter 10. 

8.1.3 Type of Gas(es). It shall be determined whether the gas 
utilization equipment has been designed for use with the gas 
to which it will be connected. No attempt shall be made to 
convert the equipment from the gas specified on the rating 
plate for use with a different gas without consulting the instal- 
lation instruction, the serving gas supplier, or the equipment 
manufacturer for complete instructions. 

8.1.4 Safety Shutoff Devices for Unlisted LP-Gas Equipment 
Used Indoors. Unlisted gas utilization equipment for use with 
undiluted liquefied petroleum gases and installed indoors 
shall be equipped with safety shutoff devices of the complete 
shutoff type. 

8.1.5 Use of Air or Oxygen Under Pressure. Where air or oxy- 
gen under pressure is used in connection with the gas supply, 
effective means such as a back-pressure regulator and relief 
valve shall be provided to prevent air or oxygen from passing 
back into the gas piping. Where oxygen is used, installation 
shall be in accordance with NFPA51, Standard for the Design and 
Installation of Oxygen-Fuel Gas Systems for Welding, Cutting, and 
Allied Processes. 

8.1.6* Protection of Gas Equipment from Fumes or Gases 
Other than Products of Combustion. 

8.1.6.1 Where corrosive or flammable process fumes or gases 
are present, means for their safe disposal shall be provided. 
Such fumes or gases include carbon monoxide, hydrogen sul- 
fide, ammonia, chlorine, and halogenated hydrocarbons. 

8.1.6.2 Non-direct-vent type gas appliances installed in 
beauty shops, barber shops, or other facilities where chemicals 
that generate corrosive or flammable products such as aerosol 
sprays are routinely used shall be located in an equipment 
room separate or partitioned off from other areas with provi- 
sions for combustion and dilution air from outdoors. Direct 
vent equipment shall be in accordance with the appliance 
manufacturer's installation instructions. 

8.1.7 Process Air. In addition to air needed for combustion in 
commercial or industrial processes, process air shall be pro- 
vided as required for cooling of equipment or material, con- 
trolling dew point, heating, drying, oxidation, dilution, safety 
exhaust, odor control, air for compressors, and for comfort 
and proper working conditions for personnel. 

8.1.8 Building Structiu-al Members. 

8.1.8.1 Structural members of a building shall not pass 
through gas utilization equipment having an operating tem- 
perature in excess of 500°F (260°C). 

8.1.8.2 Structural members passing through gas utilization 
equipment having an operating temperature of 500°F 
(260°C) or less shall be of noncombustible material. Building 
columns, girders, beams, or trusses shall not be installed 
within equipment, unless insulation and ventilation are pro- 
vided to avoid all deterioration in strength and linear expan- 
sion of the building structure in either a vertical or a horizon- 
tal direction., 

8.1.8.3 Gas utilization equipment shall be furnished either 
with load distributing bases or with a sufficient number of sup- 
ports to prevent damage to either the building structure or 
equipment. 



2002 Edition 



54-28 



NATIONAL FUEL GAS CODE 



ANSI Z223. 1-28 



8.1.8.4 At the locations selected for installation of gas utiliza- 
tion equipment, the dynamic and static load-carrying capaci- 
ties of the building structure shall be checked to determine 
whether they are adequate to carry the additional loads. The 
equipment shall be supported and shall be connected to the 
piping so as not to exert undue stress on the connections. 

8.1.9 Flaimnable Vapors. Gas appliances shall not be installed 
in areas where the open use, handling, or dispensing of flam- 
mable liquids occurs, unless the design, operation, or installa- 
tion reduces the potential of ignition of the flammable vapors. 
Gas utilization equipment installed in compliance with 8.1.10 
through 8.1.12 shall be considered to comply with the intent 
of this provision. 

8.1.10 Installation in Residential Garages. 

8.1.10.1 Gas utilization equipment in residential garages and 
in adjacent spaces that open to the garage and are not part of 
the living space of a dwelling unit shall be installed so that all 
burners and burner ignition devices are located not less than 
18 in. (460 mm) above the floor unless listed as flammable 
vapor ignition resistant. 

8.1.10.2 Such equipment shall be located or protected so it is 
not subject to physical damage by a moving vehicle. 

8.1.10.3 When appliances are installed in a separate, en- 
closed space having access only from outside of the garage, 
such equipment shall be permitted to be installed at floor 
level, providing the required combustion air is taken from the 
exterior of the garage. 

8.1.11 Installation in Commercial Garages. 

8.1.11.1 Parking Structures. Gas utilization equipment in- 
stalled in enclosed, basement, and underground parking 
structures shall be installed in accordance vsdth NFPA 88A, 
Standard for Parking Structures. 

8.1.11.2 Repair Garages. Gas utilization equipment installed 
in repair garages shall be installed in a detached building or 
room, separated from repair areas by walls or partitions, 
floors, or floor ceiling assemblies that are constructed so as to 
prohibit the transmission of vapors and having a fire resis- 
tance rating of not less than 1 hour, and that have no openings 
in the wall separating the repair area within 8 ft (2.4 m) of the 
floor. Wall penetrations shall be firestopped. Air for combus- 
tion purposes shall be obtained from outside the building. 
The heating room shall not be used for the storage of combus- 
tible materials. 

Exception No. 1: Overhead heaters where installed not less than 8 ft 
(2.4 m) above the floor shall be permitted. 

Exception No. 2: Heating equipment for vehicle repair areas where 
there is no dispensing or transferring of Class I or Class II flammable 
or combustible liquids or liquefied petroleum gas shall be installed in 
accordance with NFPA BOA, Code for Motor Fuel Dispensing Facilities 
and Repair Garages. 

8.1.12 Installation in Aircraft Hangars. Heaters in aircraft 
hangars shall be installed in accordance with NFPA 409, Stan- 
dard on Aircraft Hangars. 

8.1.13 Gas Equipment Physical Protection. Where it is neces- 
sary to locate gas utilization equipment close to a passageway 
traveled by vehicles or equipment, guardrails or bumper plates 
shall be installed to protect the equipment from damage. 



8.1.14 Venting of Flue Gases. Gas utilization equipment shall 
be vented in accordance with the provisions of Chapter 10. 

8.1.15 Extra Device or Attachment. No device or attachment 
shall be installed on any gas utilization equipment that could 
in any way impair the combustion of gas. 

8.1.16 Adequate Capacity of Piping. When additional gas uti- 
lization equipment is being connected to a gas piping system, 
the existing piping shall be checked to determine whether it 
has adequate capacity. (See Section 5. ^.j Where inadequate, the 
existing system shall be enlarged as necessary, or separate gas 
piping of adequate capacity shall be run from the point of 
delivery to the equipment. 

8.1.17 Avoiding Strain on Gas Piping. Gas utilization equip- 
ment shall be supported and so connected to the piping as not 
to exert undue strain on the connections. 

8.1.18 Gas Appliance Pressure Regulators. Where the gas sup- 
ply pressure is higher than that at which the gas utilization 
equipment is designed to operate or varies beyond the design 
pressure limits of the equipment, a gas appliance pressure 
regulator shall be installed. 

8. 1. 19 Venting of Gas Appliance Pressure Regulators. Venting 
of gas appliance pressure regulators shall comply with the fol- 
lowdng requirements: 

(1) Gas appliance pressure regulators requiring access to the 
atmosphere for successful operation shall be equipped 
with vent piping leading outdoors or, if the regulator vent 
is an integral part of the equipment, into the combustion 
chamber adjacent to a continuous pilot, unless con- 
structed or equipped with a vent limiting means to limit 
the escape of gas from the vent opening in the event of 
diaphragm failure. 

(2) Vent limiting means shall be employed on listed gas appli- 
ance pressure regulators only. 

(3) In the case of vents leading outdoors, means shall be em- 
ployed to prevent water from entering this piping and 
also to prevent blockage of vents by insects and foreign 
matter. 

(4) Under no circumstances shall a regulator be vented to the 
gas utilization equipment flue or exhaust system. 

(5) In the case of vents entering the combustion chamber, 
the vent shall be located so the escaping gas vnW be readily 
ignited by the pilot and the heat liberated thereby will not 
adversely affect the normal operation of the safety shutoff 
system. The terminus of the vent shall be securely held in 
a fixed position relative to the pilot. For manufactured 
gas, the need for a flame arrester in the vent piping shall 
be determined. 

(6) Avent line(s) from a gas appliance pressure regulator and 
a bleed line(s) from a diaphragm-type valve shall not be 
connected to a common manifold terminating in a com- 
bustion chamber. Vent lines shall not terminate in 
positive-pressure-type combustion chambers. 

8.1.20 Bleed Lines for Diaphragm-Type Valves. Bleed lines 
shall comply vsdth the following requirements: 

(1) Diaphragm-type valves shall be equipped to convey bleed 
gas to the outside atmosphere or into the combustion 
chamber adjacent to a continuous pilot. 

(2) In the case of bleed lines leading outdoors, means shall be 
employed to prevent water from entering this piping and 
also to prevent blockage of vents by insects and foreign 
matter. 



2002 Edition 



ANSI Z223. 1-29 



EQUIPMENT INSTALLATION 



54-29 



(3) Bleed lines shall not terminate in the gas utilization 
equipment flue or exhaust system. 

(4) In the case of bleed lines entering the combustion cham- 
ber, the bleed line shall be located so the bleed gas will be 
readily ignited by the pilot and the heat liberated thereby 
will not adversely aifect the normal operation of the safety 
shutoflF system. The terminus of the bleed line shall be 
securely held in a fixed position relative to the pilot. For 
manufactured gas, the need for a flame arrester in the 
bleed line piping shall be determined. 

(5) A bleed line(s) from a diaphragm-type valve and a vent 
line(s) from a gas appliance pressure regulator shall not 
be connected to a common manifold terminating in a 
combustion chamber. Bleed lines shall not terminate in 
positive-pressure-type combustion chambers. 

8.1.21 Combination of Equipment. Any combination of gas 
utilization equipment, attachments, or devices used together 
in any manner shall comply with the standards that apply to 
the individual equipment. 

8.1.22 Installation Instructions. The installing agency shall 
conform with the equipment manufacturers' recommenda- 
tions in completing an installation. The installing agency shall 
leave the manufacturers' installation, operating, and mainte- 
nance instructions in a location on the premises where they 
will be readily available for reference and guidance of the au- 
thority having jurisdiction, service personnel, and the owner 
or operator. 

8.1.23 Protection of Outdoor Equipment. Gas utilization 
equipment not listed for outdoor installation but installed out- 
doors shall be provided with protection to the degree that the 
environment requires. Equipment listed for outdoor installa- 
tion shall be permitted to be installed without protection in 
accordance v«th the provisions of their listing. (See 8.2.1.) 

8.2 Accessibility and Clearance. 

8.2.1 Accessibility for Service. All gas utilization equipment 
shall be located with respect to building construction and 
other equipment so as to permit access to the gas utilization 
equipment. Sufficient clearance shall be maintained to permit 
cleaning of heating surfaces; the replacement of filters, blow- 
ers, motors, burners, controls, and vent connections; the lu- 
brication of moving parts where necessary; the adjustment 
and cleaning of burners and pilots; and the proper function- 
ing of explosion vents, if provided. For attic installation, the 
passageway and servicing area adjacent to the equipment shall 
be floored. 

8.2.2 Clearance to Combustible Materials. Gas utilization 
equipment and their vent connectors shall be installed with 
clearances from combustible material so their operation will 
not create a hazard to persons or property. Minimum clear- 
ances between combustible walls and the back and sides of 
various conventional types of equipment and their vent con- 
nectors are specified in Chapters 9 and 10. (Reference can also be 
made to NFPA 211, Standard for Chimneys, Fireplaces, Vents, and 
Solid Fuel-Burning Appliances. ) 

8.2.3 Installation on Carpeting. Equipment shall not be in- 
stalled on carpeting, unless the equipment is listed for such 
installation. 

8.3* Air for Combustion and Ventilation. 

8.3.1 General. 

8.3.1.1 Air for combustion, ventilation, and dilution of flue 
gases for gas utilization equipment installed in buildings shall 



be obtained by application of one of the methods covered in 
8.3.2 through 8.3.6. Where the requirements of 8.3.2 are not 
met, outdoor air shall be introduced in accordance with meth- 
ods covered in 8.3.3 through 8.3.6. 

Exception No. 1: This provision shall not apply to direct vent 
appliances. 

Exception No. 2: Type I clothes dryers that are provided with makeup 
air in accordance with 9.4.3. 

8.3.1.2 Gas appliances of other than natural draft design and 
other than Category I vented appliances shall be provided 
vsdth combustion, ventilation, and dilution air in accordance 
with the appliance manufacturer's instructions. 

8.3.1.3 Equipment shall be located so as not to interfere with 
proper circulation of combustion, ventilation, and dilution air. 

8.3.1.4 Where used, a draft hood or a barometric draft regu- 
lator shall be installed in the same room or enclosure as the 
equipment served so as to prevent any diflierence in pressure 
between the hood or regulator and the combustion air supply. 

8.3.1.5 Make-up air requirements for the operation of ex- 
haust fans, kitchen ventilation systems, clothes dryers, and 
fireplaces shall be considered in determining the adequacy of 
a space to provide combustion air requirements. 

8.3.2 Indoor Combustion Air. The required volume of indoor 
air shall be determined in accordance with the method in 
8.3.2.1 or 8.3.2.2 except that where the air infiltration rate is 
known to be less than 0.40 ACH, the method in 8.3.2.2 shall be 
used. The total required volume shall be the sum of the re- 
quired volume calculated for all appliances located within the 
space. Rooms communicating direcdy with the space in which 
the appliances are installed through openings not furnished 
with doors, and through combustion air openings sized and 
located in accordance with 8.3.2.3 are considered a part of the 
required volume. 

8.3.2.1* Standard Method. The minimum required volume 
shall be 50 ft^ per 1000 Btu/hour (4.8 m^/kW). 

8.3.2.2* Known Air Infiltration Rate Method. Where the air 
infiltration rate of a structure is known, the minimum re- 
quired volume shall be determined as follows: 

(1) For appliances other than fan-assisted, calculate using the 
following equation: 



Required Volume 



AC// UOOO Btu/hr 



(2) For fan-assisted appliances, calculate using the following 
equation: 



Required Volume 



15 ft^' 



fan 



ACH 



1000 Btu/hr 



where: 
hiher - ^11 appliances other than fan-assisted input in 

Btu per hour 
i^„„ = fan-assisted appliance input in Btu per hour 
ACH - air change per hour (percent of volume of space 

exchanged per hour, expressed as a decimal) 

(3) For purposes of this calculation, an infiltration rate 
greater than 0.60 AC// shall not be used in the equations 

in 8.3.2.2(1) and 8.3.2.2(2). 



2002 Edition 



54-30 



NATIONAL FUEL GAS CODE 



ANSI Z223. 1-30 



8.3.2.3 Indoor Opening Size and Location. Openings used to 
connect indoor spaces shall be sized and located in accor- 
dance with the following: 

(l)*Combining spaces on the same story. Each opening shall 
have a minimum free area of 1 in.^/1000 Btu/hr 
(2200 mm^/kW) of the total input rating of all gas utiliza- 
tion equipment in the space, but not less than 100 in.^ 
(0.06 m^). One opening shall commence within 12 in. 
(300 mm) of the top, and one opening shall commence 
within 12 in. (300 mm) of the bottom, of the enclosure 
[see Figure A.8. 3. 2. 3(1)]. The minimum dimension of air 
openings shall be not less than 3 in. (80 mm). 

(2) Combining spaces in different stories. The volumes of 
spaces in different stories shall be considered as commu- 
nicating spaces where such spaces are connected by one 
or more openings in doors or floors having a total mini- 
mum free area of 2 in.^/ 1000 Btu/hr (4400 mmVkW) of 
total input rating of all gas utilization equipment. 

8.3.3 Outdoor Combustion Air. Outdoor combustion air shall 
be provided through opening (s) to the outdoors in accor- 
dance with the methods in 8.3.3.1 or 8.3.3.2. The minimum 
dimension of air openings shall not be less than 3 in. (80 mm) . 

8.3.3.1 Two Permanent Openings Method. Two permanent 
openings, one commencing within 12 in. (300 mm) of the top 
and one commencing within 12 in. (300 mm) of the bottom of 
the enclosure, shall be provided. The openings shall commu- 
nicate directly, or by ducts, v«th the outdoors or spaces that 
freely communicate with the outdoors, as follows: 

(l)*Where directly communicating with the outdoors or 
where communicating to the outdoors through vertical 
ducts, each opening shall have a minimum free area of 
1 in.^/4000 Btu/hr (550 mm^/kW) of total input rating 
of all equipment in the enclosure. [See Figure 
A.8.3.3.1(l)(a) and Figure A.8.3.3.1(l)(b).] 

(2) '''Where communicating with the outdoors through hori- 
zontal ducts, each opening shall have a minimum free 
area of 1 in.2/2000 Btu/hr (1100 mmVkW) of total input 
rating of all equipment in the enclosure. [See Figure 
A.8.3.3.1(2).] 

8.3.3.2* One Permanent Opening Method. One permanent 
opening, commencing within 12 in. (300 mm) of the top of 
the enclosure, shall be provided. The equipment shall have 
clearances of at least 1 in. (25 mm) from the sides and back 
and 6 in. (150 mm) from the front of the appliance. The 
opening shall directly communicate with the outdoors or 
shall communicate through a vertical or horizontal duct to 
the outdoors or spaces that freely communicate with the 
outdoors (see Figure A. 8. 3. 3. 2) and shall have a minimum 
free area of the following: 

(1)1 in.VSOOO Btu/hr (700 mm^ per kW) of the total input 
rating of all equipment located in the enclosure, and 

(2) Not less than the sum of the areas of all vent connectors in 
the space 

8.3.4 Combination Indoor and Outdoor Combustion Air. The 

use of a combination of indoor and outdoor combustion air 
shall be in accordance with (1) through (3) (see example calcu- 
lation in Annex J): 

( 1 ) Indoor Openings. Where used, openings connecting the in- 
terior spaces shall comply with 8.3.2.3. 

(2) Outdoor Opening(s) Location. Outdoor opening(s) shall be 
located in accordance with 8.3.3. 



(3) Outdoor Opening(s) Size. The outdoor opening(s) size shall 
be calculated in accordance with the following: 

(a) The ratio of the interior spaces shall be the available 
volume of all communicating spaces divided by the 
required volume. 

(b) The outdoor size reduction factor shall be 1 minus 
the ratio of interior spaces. 

(c) The minimum size of outdoor opening(s) shall be 
the full size of outdoor opening(s) calculated in ac- 
cordance with 8.3.3, multiplied by the reduction fac- 
tor. The minimum dimension of air openings shall 
not be less than 3 in. (80 mm). 

8.3.5 Engineered Installations. Engineered combustion air in- 
stallations shall provide an adequate supply of combustion, 
ventilation, and dilution air and shall be approved by the au- 
thority having jurisdiction. 

8.3.6 Mechanical Combustion Air Supply. Where all combus- 
tion air is provided by a mechanical air supply system, the 
combustion air shall be supplied from outdoors at the mini- 
mum rate of 0.35 ftVmin per 1000 Btu/hr (0.034 m^/min per 
kW) for all appliances located within the space. 

8.3.6.1 Where exhaust fans are installed, additional air shall 
be provided to replace the exhausted air. 

8.3.6.2 Each of the appliances served shall be interlocked to the 
mechanical air supply system to prevent main burner operation 
where the mechanical air supply system is not in operation. 

8.3.6.3 Where combustion air is provided by the building's 
mechanical ventilation system, the system shall provide the 
specified combustion air rate in addition to the required ven- 
tilation air. 

8.3.7 Louvers and Grilles. 

8.3.7.1 The required size of openings for combustion, venti- 
lation, and dilution air shall be based on the net free area of 
each opening. Where the free area through a design of louver 
or grille is known, it shall be used in calculating the size open- 
ing required to provide the free area specified. Where the 
design and free area are not known, it shall be assumed that 
wood louvers will have 25 percent free area, and metal louvers 
and grilles will have 75 percent free area. Nonmotorized lou- 
vers and grilles shall be fixed in the open position. 

8.3.7.2 Motorized louvers shall be interlocked with the equip- 
ment so they are proven in the full open position prior to 
main burner ignition and during main burner operation. 
Means shall be provided to prevent the main burner from 
igniting should the louver fail to open during burner startup 
and to shut down the main burner if the louvers close during 
burner operation. 

8.3.8 Combustion Air Ducts. Combustion air ducts shall com- 
ply with the following. 

8.3.8.1 Ducts shall be of galvanized steel or an equivalent 
corrosion-resistant material. 

Exception: Within dwellings units, unobstructed stud and joist 
spaces shall not be prohibited from conveying combustion air, provided 
that not more than onefireblock is removed. 

8.3.8.2 Ducts shall terminate in an unobstructed space, allow- 
ing free movement of combustion air to the appliances. 

8.3.8.3 Ducts shall serve a single space. 



2002 Edition 



ANSI Z223.1-31 



EQUIPMENT INSTALLATION 



54-31 



8.3.8.4 Ducts shall not serve both upper and lower combus- 
tion air openings where both such openings are used. The 
separation between ducts serving upper and lower combus- 
tion air openings shall be maintained to the source of combus- 
tion air. 

8.3.8.5 Ducts shall not be screened where terminating in an 
attic space. 

8.3.8.6 Horizontal upper combustion air ducts shall not 
slope downward toward the source of combustion air. 

8.3.8.7 The remaining space surrounding a chimney liner, 
gas vent, special gas vent, or plastic piping installed within a 
masonry, metal, or factory built chimney shall not be used to 
supply combustion air. 

Exception: Direct vent gas-fired appliances designed for installation 
in a solid fuel burning fireplace where installed in accordance with the 
listing and the manufacturer's instruction. 

8.3.8.8 Combustion air intake openings located on the exte- 
rior of the building shall have the lowest side of the combus- 
tion air intake openings located at least 12 in. (300 mm) verti- 
cally from the adjoining grade level. 

8.4 Equipment on Roofs. 

8.4.1 General. 

8.4.1.1 Gas utilization equipment on roofs shall be designed 
or enclosed so as to withstand climatic conditions in the area 
in which they are installed. Where enclosures are provided, 
each enclosure shall permit easy entry and movement, shall be 
of reasonable height, and shall have at least a 30 in. (760 mm) 
clearance between the entire service access panel (s) of the 
equipment and the wall of the enclosure. 

8.4.1.2 Roofs on which equipment is to be installed shall be 
capable of supporting the additional load or shall be rein- 
forced to support the additional load. 

8.4.1.3 All access locks, screws, and bolts shall be of 
corrosion-resistant material. 

8.4.2 Installation of Equipment on Roofs. 

8.4.2.1 Gas utilization equipment shall be installed in accor- 
dance with its listing and the manufacturer's installation in- 
structions. 

8.4.2.2 Equipment shall be installed on a well-drained sur- 
face of the roof. At least 6 ft (1.8 m) of clearance shall be 
available between any part of the equipment and the edge of a 
roof or similar hazard, or rigidly fixed rails, guards, parapets, 
or other building structures at least 42 in. (1.1 m) in height 
shall be provided on the exposed side. 

8.4.2.3 All equipment requiring an external source of electri- 
cal power for its operation shall be provided with (1) a readily 
accessible electrical disconnecting means within sight of the 
equipment that will completely deenergize the equipment, 
and (2) a 120-V ac grounding-type receptacle outlet on the 
roof adjacent to the equipment. The receptacle outlet shall be 
on the supply side of the disconnect switch. 

8.4.2.4 Where water stands on the roof at the equipment or 
in the passageways to the equipment, or where the roof is of a 
design having a water seal, a suitable platform, walkway, or 
both shall be provided above the water line. Such platform (s) 
or walkway(s) shall be located adjacent to the equipment and 



control panels so that the equipment can be safely serviced 
where water stands on the roof. 

8.4.3 Access to Equipment on Roofs. 

8.4.3.1 Gas utilization equipment located on roofs or other 
elevated locations shall be accessible. 

8.4.3.2 Buildings of more than 15 ft (4.6 m) in height shall 
have an inside means of access to the roof, unless other means 
acceptable to the authority having jurisdiction are used. 

8.4.3.3 The inside means of access shall be a permanent or 
foldaway inside stairway or ladder, terminating in an enclo- 
sure, scuttle, or trapdoor. Such scuttles or trapdoors shall be at 
least 22 in. x 24 in. (560 mm x 610 mm) in size, shall open 
easily and safely under all conditions, especially snow, and 
shall be constructed so as to permit access from the roof side 
unless deliberately locked on the inside. At least 6 ft ( 1 .8 m) of 
clearance shall be available between the access opening and 
the edge of the roof or similar hazard, or rigidly fixed rails or 
guards a minimum of 42 in. (1.1 m) in height shall be pro- 
vided on the exposed side. Where parapets or other building 
structures are utilized in lieu of guards or rails, they shall be a 
minimum of 42 in. (1.1 m) in height. 

8.4.3.4 Permanent lighting shall be provided at the roof ac- 
cess. The switch for such lighting shall be located inside the 
building near the access means leading to the roof. 

8.4.4 Additional Provisions. (Also see 8.1.23, 8.2.1, and 10.3.4.) 
8.5 Equipment Connections to Building Piping. 

8.5.1 Connecting Gas Equipment. Gas utilization equipment 
shall be connected to the building piping in compliance with 
8.5.4 through 8.5.6 by one of the following: 

(1) Rigid metallic pipe and fittings. 

(2) Semirigid metallic tubing and metallic fittings. Aluminum 
alloy tubing shall not be used in exterior locations. 

(3) A listed connector in compliance with ANSI Z21.24, Stan- 
dard for Connectors for Gas Appliances. The connector shall 
be used in accordance with the terms of its listing and 
shall be in the same room as the equipment. Only one 
connector shall be used per appliance. 

(4) CSST where installed in accordance vwth the manufactur- 
er's instructions. 

(5) Listed nonmetallic gas hose connectors in accordance 
with 8.5.2. 

(6) Gas-fired food service (commercial cooking) equipment 
listed for use vwth casters or otherwise subject to move- 
ment for cleaning, and other large and heavy gas utiliza- 
tion equipment that can be moved, shall be connected in 
accordance vsdth the connector manufacturer's installa- 
tion instructions using a listed appliance connector com- 
plying with ANSI Z21.69, Connectors for Movable Gas Appli- 
ances. 

(7) In 8.5.1(2), 8.5.1(3), and 8.5.1(5), the connector or tub- 
ing shall be installed so as to be protected against physical 
and thermal damage. Aluminum alloy tubing and connec- 
tors shall be coated to protect against external corrosion 
where they are in contact with masonry, plaster, or insula- 
tion or are subject to repeated wettings by such liquids as 
water (except rain water), detergents, or sewage. 

8.5.2 Use of Nonmetallic Gas Hose Connectors. Listed gas 
hose connectors shall be used in accordance with the terms of 
their listing and as follows: 



2002 Edition 



54-32 



NATIONAL FUEL GAS CODE 



ANSI Z223. 1-32 



(1) Indoor. Indoor gas hose connectors shall be used only to 
connect laboratory, shop, and ironing equipment requir- 
ing mobility during operation. An equipment shutoff 
valve shall be installed where the connector is attached to 
the building piping. The connector shall be of minimum 
length and shall not exceed 6 ft (L8 m). The connector 
shall not be concealed and shall not extend from one 
room to another or pass through wall partitions, ceilings, 
or floors. 

(2) Outdoor. Outdoor gas hose connectors are permitted to 
connect portable outdoor gas-fired equipment. An equip- 
ment shutoff" valve, a listed quick-disconnect device, or a 
listed gas convenience outlet shall be installed where the 
connector is attached to the supply piping and in such a 
manner so as to prevent the accumulation of water or 
foreign matter. This connection shall only be made in the 
outdoor area where the equipment is to be used. 

8.5.3 Connection of Portable and Mobile Industrial Gas 
Equipment. 

8.5.3.1 Where portable industrial gas utilization equipment 
or equipment requiring mobility or subject to vibration is con- 
nected to the building gas piping system by the use of a flex- 
ible hose, the hose shall be suitable and safe for the conditions 
under which it can be used. 

8.5.3.2 Where industrial gas utilization equipment requiring 
mobility is connected to the rigid piping by the use of swivel 
joints or couplings, the swivel joints or couplings shall be suit- 
able for the service required and only the minimum number 
required shall be installed. 

8.5.3.3 Where industrial gas utilization equipment subject to 
vibration is connected to the building piping system by the use 
of all metal flexible connectors, the connectors shall be suit- 
able for the service required. 

8.5.3.4 Where flexible connections are used, they shall be of 
the minimum practical length and shall not extend from one 
room to another or pass through any walls, partitions, ceilings, 
or floors. Flexible connections shall not be used in any con- 
cealed location. They shall be protected against physical or 
thermal damage and shall be provided with gas shutoff valves 
in readily accessible locations in rigid piping upstream from 
the flexible connections. 

8.5.4 Equipment Shutoff Valves and Connections. Gas utiliza- 
tion equipment connected to a piping system shall have an 
accessible, approved manual shutoff valve with a nondisplace- 
able valve member, or a listed gas convenience outlet, in- 
stalled within 6 ft (1.8 m) of the equipment it serves. Where a 
connector is used, the valve shall be installed upstream of the 
connector. A union or flanged connection shall be provided 
downstream from this valve to permit removal of controls. 
Shutoff valves serving decorative gas appliances shall be per- 
mitted to be installed in fireplaces if listed for such use. 

8.5.5 Quick-Disconnect Devices. Quick-disconnect devices 
used to connect equipment to the building piping shall be 
listed. Where installed indoors, an approved manual shutoff 
valve with a nondisplaceable valve member shall be installed 
upstream of the quick-disconnect device. 

8.5.6* Gas Convenience Outlets. Gas utilization equipment 
shall be permitted to be connected to the building piping by 
means of a listed gas convenience outlet, in conjunction with a 
listed appliance connector, used in accordance with the terms 
of their listings. 



8.5.7 Sediment Trap. Where a sediment trap is not incorpo- 
rated as a part of the gas utilization equipment, a sediment 
trap shall be installed as close to the inlet of the equipment as 
practicable at the time of equipment installation. The sedi- 
ment trap shall be either a tee fitting with a capped nipple in 
the bottom outlet as illustrated in Figure 8.5.7 or other device 
recognized as an effective sediment trap. Illuminating appli- 
ances, ranges, clothes dryers, decorative appliances for instal- 
lation in vented fireplaces, gas fireplaces, and outdoor grills 
shall not be required to be so equipped. 



Gas supply inlet 






To 

equipment 

inlet 



-Tee fitting 



Nipple — > 
Cap^-r 



f 

3 in. (80 mm) 

minimum 



FIGURE 8.5.7 Method of Installing a Tee Fitting Sediment 
Trap. 



8.5.8 Installation of Piping. Piping shall be installed in a man- 
ner not to interfere with inspection, maintenance, or servicing 
of the gas utilization equipment. 

8.6 Electrical. 

8.6.1 Electrical Connections. Electrical connections between 
gas utilization equipment and the building wiring, including 
the grounding of the equipment, shall conform to NFPA 70, 

National Electrical Code. 

8.6.2 Electrical Ignition and Control Devices. Electrical igni- 
tion, burner control, and electrical vent damper devices shall 
not permit unsafe operation of the gas utilization equipment 
in the event of electrical power interruption or when the 
power is restored. 

8.6.3 Electrical Circuit. The electrical circuit employed for op- 
erating the automatic main gas-control valve, automatic pilot, 
room temperature thermostat, limit control, or other electrical 
devices used with the gas utilization equipment shall be in accor- 
dance with the wiring diagrams supplied with the equipment. 

8.6.4 Continuous Power. All gas utilization equipment using 
electrical controls shall have the controls connected into a 
permanendy live electrical circuit — that is, one that is not 
controlled by a light switch. Central heating equipment shall 
be provided with a separate electrical circuit. 

8.7 Room Temperature Thermostats. 

8.7.1 Locations. Room temperature thermostats shall be in- 
stalled in accordance with the manufacturers' instructions. 

8.7.2 Drafts. Any hole in the plaster or panel through which 
the wires pass from the thermostat to the gas utilization equip- 
ment being controlled shall be sealed so as to prevent drafts 
from affecting the thermostat. 



2002 Edition 



ANSI Z223. 1-33 



INSTALLATION OF SPECIFIC EQUIPMENT 



54-33 



Chapter 9 Installation of Specific Equipment 

9.1 General. 

9.1.1 Application. This chapter is appHcable primarily to 
nonindustrial-type gas utilization equipment and installations 
and, unless specifically indicated, does not apply to industrial- 
type equipment and installations. Listed gas utiUzation equip- 
ment shall be installed in accordance with their listing and the 
manufacturers' instructions, or as elsewhere specified in this 
chapter. Unlisted equipment shall be installed as specified in 
this part as applicable to the equipment. For additional infor- 
mation concerning particular gas equipment and accessories, 
including industrial types, reference can be made to the stan- 
dards listed in Chapter 14 and Annex L. 

9.1.2* Installation in a Bedroom or Bathroom. Gas utilization 
equipment shall not be installed so its combustion, ventila- 
tion, and dilution air are obtained only from a bedroom or 
bathroom unless the bedroom or bathroom has the required 
volume in accordance with 8.3.2. 

9.1.3 Room Size in Comparison Calculation. Where the room 
size in comparison with the size of the equipment is to be 
calculated, the total volume of the appliance is determined 
from exterior dimensions and is to include fan compartments 
and burner vestibules, where used. Where the actual ceiling 
height of a room is greater than 8 ft (2.4 m), the volume of the 
room is figured on the basis of a ceiling height of 8 ft (2.4 m). 

9.2 Air-Conditioning Equipment (Gas-Fired Air Conditioners 
and Heat Pumps). 

9.2.1 Independent Gas Piping. Gas piping serving heating gas 
utilization equipment shall be permitted to also serve cooling 
equipment where heating and cooling equipment cannot be 
operated simultaneously. (See Section 5.4.) 



9.2.2 Connection of Gas Engine-Powered Air Conditioners. 

To protect against the effects of normal vibration in service, 
gas engines shall not be rigidly connected to the gas supply 
piping. 

9.2.3 Clearances for Indoor Installation. The installation of 
air-conditioning equipment shall comply with the followdng 
requirements: 

(1) Listed air-conditioning equipment installed in rooms that 
are large in comparison with the size of the equipment 
shall be installed with clearances per the terms of their 
listing and the manufacturer's instructions. (See Table 
9.2.3(a) and Section 3.3 for definition.) 

(2) Air-conditioning equipment installed in rooms that are 
NOT large (such as alcoves and closets) in comparison 
v«th the size of the equipment shall be listed for such 
installations and installed in accordance with the manu- 
facturer's instructions. Listed clearances shall not be re- 
duced by the protection methods described in Table 
9.2.3(b), regardless of whether the enclosure is of com- 
bustible or noncombustible material. 

(3) Unlisted air-conditioning equipment shall be installed with 
clearances from combustible material of not less than 18 in. 
(460 mm) above the equipment and at the sides, front, and 
rear and 9 in. (230 mm) from the draft hood. 

(4) Air-conditioning equipment (listed and unlisted) in- 
stalled in rooms that are large in comparison with the size 
of the equipment shall be permitted to be installed with 
reduced clearances to combustible material provided the 
combustible material or equipment is protected as de- 
scribed in Table 9.2.3(b) [see 9.2.3(2)]. 

(5) Where the furnace plenum is adjacent to plaster on metal 
lath or noncombustible material attached to combustible 
material, the clearance shall be measured to the surface 



Table 9.2.3(a) Clearances to Combustible Material for Unlisted Furnaces, Boilers, and Air Conditioners 
Installed in Rooms That Are Large in Comparison with the Size of Equipment 

Minimvun Clearance (in.) 



Equipment 



Above and 
Sides of 
Fximace 
Plenum 



Top of 
Boiler 



Jacket Sides 
and Rear 



Front 



Draft Hood and 

Barometric Single-Wall Vent 

Draft Regulator Connector 



I Automatically fired, forced 
air or gravity system, 
equipped with temperature 
limit control that cannot be 
set higher than 250°F 
(121°C) 



18 



18 



II Automatically fired heating 
boilers — steam boilers 
operating at not over 15 psi 
(103 kPa) and hot water 
boilers operating at 250°F 
(121°C) or less 



18 



18 



18 



III Central heating boilers and 
furnaces, other than in I or 
II 


18 


18 


18 


18 


18 


18 


IV Air-conditioning equipment 


18 


18 


18 


18 


18 


18 



Note: See 9.2.3 for additional requirements for air-conditioning equipment and 9.3.1 for additional 
requirements for central heating boilers and furnaces. 



2002 Edition 



54-34 



NATIONAL FUEL GAS CODE 



ANSI Z223. 1-34 



Table 9.2.3(b) Reduction of Clearances witii Specified Forms of Protection 







Where the 


required clearance with no protection from appliance, vent connector. 










or single-wall metal pipe is: 








36 in. 


18 in. 


12 in. 


9 in. 


6 in. 








Allowable Clearances with Specified Protection (in.) 






Type of protection applied 






















to and covering all surfaces 


Use Col. 1 for clearances above appliance or horizontal connector. Use Col. 


2 for clearances 


of combustible material 




from appliance, vertical connector, and single-wall metal pipe. 




within the distance specified 


























as the required clearance 




Sides 


Sides 


Sides 


Sides 




Sides 


with no protection [See 




and 


and 


and 


and 




and 


Figure 9.3.2.2(a) through 


Above 


Rear 


Above Rear 


Above Rear 


Above Rear 


Above 


Rear 


Figure 9.3.2.2(c).] 


Col. 1 


Col. 2 


Col. 1 Col. 2 


Col. 1 Col. 2 


Col. 1 Col. 2 


Col. 1 


Col. 2 


(1) 3^2 in. thick masonry 


— 


24 


— 12 


— 9 


— 6 


— 


5 


wall without ventilated air 
















space 
















(2) y2 in. insulation board 


24 


18 


12 9 


9 6 


6 5 


4 


3 


over 1 in. glass fiber or 
















mineral wool batts 
















(3) 0.024 sheet metal over 


18 


12 


9 6 


6 4 


5 3 


3 


3 


1 in. glass fiber or mineral 
















wool batts reinforced with 
















wire on rear face with 
















ventilated air space 
















(4) 3V2 in. thick masonry 


— 


12 


— 6 


— 6 


— 6 


— 


6 


wall with ventilated air 
















space 
















(5) 0.024 sheet metal with 


18 


12 


9 6 


6 4 


5 3 


3 


2 


ventilated air space 
















(6) V2 in. thick insulation 


18 


12 


9 6 


6 4 


5 3 


3 


3 


board with ventilated air 
















space 
















(7) 0.024 sheet metal with 


18 


12 


9 6 


6 4 


5 3 


3 


3 


ventilated air space over 
















0.024 sheet metal with 
















ventilated air space 
















(8) 1 in. glass fiber or 


18 


12 


9 6 


6 4 


5 3 


3 


3 


mineral wool batts 
















sandwiched between two 
















sheets 0.024 sheet metal 
















with ventilated air space 

















For SI units, 1 in. = 25.4 mm. 
Notes: 

1. Reduction of clearances from combustible materials shall not interfere with combustion air, draft hood clearance and relief, and accessibility of 
servicing. 

2. All clearances shall be measured from the outer surface of the combustible material to the nearest point on the surface of the appliance, 
disregarding any intervening protecdon applied to the combustible material. 

3. Spacers and ties shall be of noncombustible material. No spacer or tie shall be used directly opposite the appliance or connector. 

4. Where all clearance reduction systems use a ventilated air space, adequate provision for air circulation shall be provided as described. [See Figure 
9.3.2.2(b) andFigure 9.3.2.2(c).] 

5. There shall be at least 1 in. (25 mm) between clearance reduction systems and combustible walls and ceilings for reduction systems using a 
ventilated air space. 

6. Where a wall protector is mounted on a single flat wall away from corners, it shall have a minimum I in. (25 mm) air gap. To provide adequate 
air circuladon, the bottom and top edges, or only the side and top edges, or all edges shall be left open. 

7. Mineral wool batts (blanket or board) shall have a minimum density of 8 Ib/ft^ (128 kg/m^) and a minimum melting point of 1500°F (816°C). 

8. Insulation material used as part of a clearance reduction system shall have a thermal conductivity of 1.0 Btu in./ft^/hr-°F (0.144 W/m-K) or less. 

9. There shall be at least 1 in. (25 mm) between the appliance and the protector. In no case shall the clearance between the appliance and the 
combustible surface be reduced below that allowed in Table 9.2.3(b). 

10. All clearances and thicknesses are minimum; larger clearances and thicknesses are acceptable. 

11. Listed single-wall connectors shall be installed in accordance with the terms of their listing and the manufacturer's instructions. 



2002 Edition 



ANSI Z223. 1-35 



INSTALLATION OF SPECIFIC EQUIPMENT 



54-35 



of the plaster or other noncombustible finish where the 
clearance specified is 2 in. (50 mm) or less. 
(6) Listed air-conditioning equipment shall have the clear- 
ance from supply ducts within 3 ft (0.9 m) of the furnace 
plenum be not less than that specified from the furnace 
plenum. No clearance is necessary beyond this distance. 

9.2.4 Assembly and Installation. Air-conditioning equipment 
shall be installed in accordance with the manufacturer's in- 
structions. Unless the equipment is listed for installation on a 
combustible surface such as a floor or roof, or unless the sur- 
face is protected in an approved manner, it shall be installed 
on a surface of noncombustible construction with noncom- 
bustible material and surface finish and with no combustible 
material against the underside thereof. 

9.2.5 Furnace Plenums and Air Ducts. A furnace plenum sup- 
plied as a part of the air-condidoning equipment shall be in- 
stalled in accordance wdth the manufacturer's instructions. 
Where a furnace plenum is not supplied with the equipment, 
any fabrication and installation instructions provided by the 
manufacturer shall be followed. The method of connecting 
supply and return ducts shall facilitate proper circulation of 
air. Where the air conditioner is installed within a room not 
large in comparison with the size of the equipment, the air 
circulated by the equipment shall be handled by ducts that are 
sealed to the casing of the equipment and that separate the 
circulating air from the combustion and ventilation air. 

9.2.6* Refrigeration Coils. (See 9.3. 7 and 9.3.8.) 

9.2.7 Switches in Electrical Supply Line. Means for interrupt- 
ing the electrical supply to the air-conditioning equipment 
and to its associated cooling tower (if supplied and installed in 
a location remote from the air conditioner) shall be provided 
within sight of and not over 50 ft (15 m) from the air condi- 
tioner and cooling tower. 

9.3 Central Heating Boilers and Furnaces. 

9.3.1 Location. Central heating furnace and low-pressure 
boiler installations in bedrooms or bathrooms shall comply 
with one of the following: 

( 1 ) Central heating furnaces and low-pressure boilers shall be 
installed in a closet located in the bedroom or bathroom, 
the closet shall have a weather-stripped solid door with a 
self-closing device, and all combustion air shall be ob- 
tained from the outdoors. 

(2) Central heating furnaces and low-pressure boilers shall be 
of the direct vent type. 

9.3.2 Clearance. 

9.3.2.1 Listed central heating furnaces and low-pressure boil- 
ers installed in rooms that are large in comparison with the 
size of the equipment shall be installed with clearances per the 
terms of their listing and the manufacturer's instructions. (See 
Section 3.3 for definition.) 

9.3.2.2 Central heating furnaces and low-pressure boilers in- 
stalled in rooms that are NOT large (such as alcoves and clos- 
ets) in comparison with the size of the equipment shall be 
listed for such installations. Listed clearances shall not be re- 
duced by the protection methods described in Table 9.2.3(b) 
and illustrated in Figure 9.3.2.2(a) through Figure 9.3.2.2(c), 
regardless of whether the enclosure is of combustible or non- 
combustible material. 



Construction using combustible — > 
material, plastered or unplastered 



M 



X 



M 



M 



S 





Sheet metal or 
other protection 



Gas equipment 
or vent connector 



Notes: 

A equals the clearance with no protection specified in Tables 9.2.3(a) 
and 10.4.1 and in the sections applying to various types of equipment. 
6 equals the reduced clearance permitted in accordance with 
Table 9.2.3(b). The protection applied to the construction using 
combustible material shall extend far enough in each direction to 
make C equal to A. 

FIGURE 9.3.2.2(a) Extent of Protection Necessary to Reduce 
Qearances from Gas Equipment or Vent Connectors. 



Mounted with side 
and top edges open 




Wall protector mounted 
with all edges open 





Mounted with top 
and bottom edges 
open 



Wall protector mounted 
on single flat wall 



Must be mounted with top 
and bottom edges open 



Wall protector installed in corner 




Nail or screw anchor 



Clearance 
reduction system 



1 in. (25 mm) noncombustible 
spacer such as stacked washers, 
small-diameter pipe, tubing, or 
electrical conduit. 



Masonry walls can be attached to combustible walls using wall ties. 
Spacers should not be used directly behind appliance or connector. 

HGURE 9.3.2.2(b) Wall Protector Qearance Reduction System. 



2002 Edition 



54-36 



NATIONAL FUEL GAS CODE 



ANSI Z223. 1-36 



Combustible wall 




1 in. (25 mm) 
minimum air space 
between masonry 
and combustible wall 



4 in. (100 mm) 
nominal brick wall 



Bottom and top course 
of bricks staggered for 
ventilation 



A strip of heavy-gauge steel 
used for added support 

Note: Do not place masonry wall ties directly 
behind appliance or connector. 



Corrugated 
metal wall 
ties 




Masonry wall tie 



FIGURE 9.3.2.2(c) Masonry Clearance Reduction System. 



9.3.2.3 Unlisted central heating furnaces and low-pressure 
boilers installed in rooms that are large in comparison with 
the size of the equipment shall be installed with clearances not 
less than those specified in Table 9.2.3(a). 

9.3.2.4 Central heating furnaces and low-pressure boilers 
(listed and unlisted) installed in rooms that are large in com- 
parison with the size of the equipment shall be permitted to be 
installed with reduced clearances to combustible material pro- 
vided the combustible material or equipment is protected as 
described in Table 9.2.3(b) (see 9.3.2). 

9.3.2.5 Front clearance shall be sufficient for servicing the 
burner and the furnace or boiler. 

9.3.2.6 Where the furnace plenum is adjacent to plaster on 
metal lath or noncombustible material attached to combus- 
tible material, the clearance shall be measured to the surface 
of the plaster or other noncombustible finish where the clear- 
ance specified is 2 in. (50 mm) or less. 

9.3.2.7 The clearance to this equipment shall not interfere 
with combustion air, draft hood clearance and relief, and ac- 
cessibility for servicing. (See 8.2.1, Section 8.3, and 10.12. 7.) 

9.3.2.8 Listed central heating furnaces shall have the clear- 
ance from supply ducts within 3 ft (0.9 m) of the furnace ple- 
num be not less than that specified from the furnace plenum. 
No clearance is necessary beyond this distance. 

9.3.2.9 Unlisted central heating furnaces with temperature 
Hmit controls that cannot be set higher than 250°F (121°C) 
shall have the clearance from supply ducts within 6 ft (1.8 m) 
of the furnace plenum be not less than 6 in. (150 mm). No 
clearance is necessary beyond this distance. 

9.3.2.10 Central heating furnaces other than those listed in 
9.3.2.8 or 9.3.2.9 shall have clearances from the supply ducts of 
not less than 18 in. (460 mm) from the furnace plenum for the 
first 3 ft (0.9 m) , then 6 in. (150 mm) for the next 3 ft (0.9 m) and 
1 in. (25 mm) beyond 6 ft (1.8 m). 

9.3.3 Assembly and Installation. A central heating boiler or 
furnace shall be installed in accordance with the manufactur- 
er's instructions and shall be installed on a floor of noncom- 



bustible construction with noncombustible flooring and sur- 
face finish and with no combustible material against the 
underside thereof, or on fire-resistive slabs or arches having 
no combustible material against the underside thereof. 

Exception No. 1: Appliances listed for installation on a combustible 
floor. 

Exception No. 2: 
manner. 



Installation on a floor protected in an approved 



9.3.4 Temperature- or Pressure-Limiting Devices. Steam and 
hot water boilers, respectively, shall be provided with ap- 
proved automatic limiting devices for shutting down the burn- 
er (s) to prevent boiler steam pressure or boiler water tempera- 
ture from exceeding the maximum allowable working 
pressure or temperature. Safety limit controls shall not be 
used as operating controls. 

9.3.5 Low Water Cutoff. Hot water boilers installed above the 
radiation level and all steam boilers shall be provided with an 
automatic means to shut off the fuel supply to the burner (s) if 
the boiler water level drops to the lowest safe water line. 

9.3.6* Steam Safety and Pressure Relief Valves. Steam and hot 
water boilers shall be equipped, respectively, with listed or ap- 
proved steam safety or pressure relief valves of appropriate 
discharge capacity and conforming with ASME requirements. 
Ashutofi: valve shall not be placed between the relief valve and 
the boiler or on discharge pipes between such valves and the 
atmosphere. 

9.3.6.1 

floor. 



Relief valves shall be piped to discharge near the 



9.3.6.2 The entire discharged piping shall be at least the 
same size as the relief valve discharge piping. 

9.3.6.3 Discharge piping shall not contain threaded end con- 
nection at its termination point. 

9.3.7 Furnace Plenums and Air Ducts. 

9.3.7.1 Furnace plenums and air ducts shall be installed in 
accordance with NFPA 90A, Standard for the Installation ofAir- 
Conditioning and Ventilating Systems, or NFPA 90B, Standard for 
the Installation of Warm Air Heating and Air-Conditioning Systems. 

9.3.7.2 A furnace plenum supplied as a part of a furnace shall 
be installed in accordance with the manufacturer's instruc- 
tions. 

9.3.7.3* Where a furnace plenum is not supplied with the fur- 
nace, any fabrication and installation instructions provided by 
the manufacturer shall be followed. The method of connect- 
ing supply and return ducts shall facilitate proper circulation 
of air. 

9.3.7.4 Where a furnace is installed so supply ducts carry air 
circulated by the furnace to areas outside the space containing 
the furnace, the return air shall also be handled by a duct(s) 
sealed to the furnace casing and terminating outside the space 
containing the furnace. 

9.3.8 Refrigeration Coils. The installation of refrigeration 
coils shall comply with the following requirements: 

(1) A refrigeration coil shall not be installed in conjunction 
with a forced air furnace where circulation of cooled air is 
provided by the furnace blower, unless the blower has suf- 
ficient capacity to overcome the external static resistance 
imposed by the duct system and cooling coil and the air 



2002 Edition 



ANSI Z223.1-37 



INSTALLATION OF SPECIFIC EQUIPMENT 



54-37 



throughput necessary for heating or cooling, whichever is 
greater. 

(2) Furnaces shall not be located upstream from cooling 
units, unless the cooling unit is designed or equipped so 
as not to develop excessive temperature or pressure. 

(3) Refrigeration coils shall be installed in parallel with or on 
the downstream side of central furnaces to avoid conden- 
sation in the heating element, unless the furnace has 
been specifically listed for downstream installation. With a 
parallel flow arrangement, the dampers or other means 
used to control flow of air shall be sufficiently tight to 
prevent any circulation of cooled air through the furnace. 

(4) Means shall be provided for disposal of condensate and to 
prevent dripping of condensate on the heating element. 

9.3.9 Cooling Units Used with Heating Boilers. 

9.3.9.1 Boilers, where used in conjunction with refrigeration 
systems, shall be installed so that the chilled medium is piped 
in parallel with the heating boiler with appropriate valves to 
prevent the chilled medium from entering the heating boiler. 

9.3.9.2 Where hot water heating boilers are connected to 
heating coils located in air-handling units where they can be 
exposed to refrigerated air circulation, such boiler piping sys- 
tems shall be equipped with flow control valves or other auto- 
matic means to prevent gravity circulation of the boiler water 
during the cooling cycle. 

9.4 Clothes Dryers. 

9.4.1 Clearance. The installation of clothes dryers shall com- 
ply with the following requirements: 

(1) Listed Type 1 clothes dryers shall be installed with a mini- 
mum clearance of 6 in. (150 mm) from adjacent combus- 
tible material. Clothes dryers listed for installation at re- 
duced clearances shall be installed in accordance with 
their listing. Type 1 clothes dryers installed in closets shall 
be specifically listed for such installation. 

(2) Listed Type 2 clothes dryers shall be installed with clear- 
ances of not less than that shown on the marking plate 
and in the manufacturers' instructions. Type 2 clothes 
dryers designed and marked "For use only in noncombus- 
tible locations" shall not be installed elsewhere. 

(3) Unlisted clothes dryers shall be installed with clearances 
to combustible material of not less than 18 in. (460 mm). 
Combustible floors under unlisted clothes dryers shall be 
protected in an approved manner. 

9.4.2 Exhausting to the Outdoors. Type 1 and Type 2 clothes 
dryers shall be exhausted to the outside air. 

9.4.3 Provisions for Make-Up Air. 

9.4.3.1 Make-up air shall be provided for Type I clothes dryers 
in accordance with the manufacturers' installation instructions. 

9.4.3.2 Provision for make-up air shall be provided for Type 2 
clothes dryers, with a minimum free area (see 8.3.5) of 1 in.^/1000 
Btu/hr (2200 mm^/kW) total input rating of tiie dryer(s) 
installed. 

9.4.4 Exhaust Ducts for Type 1 Clothes Dryers. 

9.4.4.1 A clothes dryer exhaust duct shall not be connected 
into any vent connector, gas vent, chimney, crawl space, attic, 
or other similar concealed space. 



9.4.4.2 Ducts for exhausting clothes dryers shall not be as- 
sembled with screws or other fastening means that extend into 
the duct and that would catch lint and reduce the efficiency of 
the exhaust system. 

9.4.4.3 Exhaust ducts shall be constructed of rigid metallic 
material. Transition ducts used to connect the dryer to the 
exhaust duct shall be listed for that application or installed in 
accordance with the clothes dryer manufacturer's installation 
instructions. 

9.4.5 Exhaust Ducts for Type 2 Clothes Dryers. 

9.4.5.1 Exhaust ducts for Type 2 clothes diyers shall comply 
with 9.4.4. 

9.4.5.2 Exhaust ducts for Type 2 clothes dryers shall be con- 
structed of sheet metal or other noncombustible material. 
Such ducts shall be equivalent in strength and corrosion resis- 
tance to ducts made of galvanized sheet steel not less than 
0.0195 in. (0.5 mm) thick. 

9.4.5.3 Type 2 clothes dryers shall be equipped or installed 
with lint-controlling means. 

9.4.5.4 Exhaust ducts for Type 2 clothes dryers shall be in- 
stalled with a minimum clearance of 6 in. (150 mm) from 
adjacent combustible material. Where exhaust ducts for Type 
2 clothes dryers are installed with reduced clearances, the ad- 
jacent combustible material shall be protected in accordance 
with Table 9.2.3(b). 

9.4.5.5 Where ducts pass through walls, floors, or partitions, 
the space around the duct shall be sealed with noncombus- 
tible material. 

9.4.5.6 Multiple installations of Type 2 clothes dryers shall be 
made in a manner to prevent adverse operation due to back 
pressures that might be created in the exhaust systems. 

9.4.6 Multiple Family or Public Use. All clothes dryers in- 
stalled for multiple-family or public use shall be equipped with 
approved safety shutoflF devices and shall be installed as speci- 
fied for a Type 2 clothes dryer under 9.4.5. 

9.5 Conversion Burners. Installation of conversion burners 
shall conform to ANSI Z21.8, Installation of Domestic Gas Conver- 
sion Burners. 

9.6 Decorative Appliances for Installation in Vented Fire- 
places. 

9.6.1* Prohibited Installations. Decorative appliances for in- 
stallation in vented fireplaces shall not be installed in bath- 
rooms or bedrooms unless the appliance is listed and the bed- 
room or bathroom has the required volume in accordance 
with 8.3.2. 

9.6.2 Installation. A decorative appliance for installation in a 
vented fireplace shall be installed only in a vented fireplace 
having a working chimney flue and constructed of noncom- 
bustible materials. These appliances shall not be thermostati- 
cally controlled. 

9.6.2.1 A listed decorative appliance for installation in a 
vented fireplace shall be installed in accordance with its listing 
and the manufacturer's instructions. 

9.6.2.2 Adecorative appliance for installation in a vented fire- 
place, where installed in a manufactured home, shall be listed 
for installation in manufactured homes. 



2002 Edition 



54-38 



NATIONAL FUEL GAS CODE 



ANSI Z223. 1-38 



9.6.2.3 An unlisted decorative appliance for installation in a 
vented fireplace shall be installed in a fireplace having a per- 
manent free opening, based on appliance input rating and 
chimney height equal to or greater than that specified in 
Table 9.6.2.3. 

9.6.3 Fireplace Screens. A fireplace screen shall be installed 
with a decorative appliance for installation in a vented fire- 
place. 

9.7 Gas Fireplaces, Vented. 

9.7.1* Prohibited Installations. Vented gas fireplaces shall not 
be installed in bathrooms or bedrooms unless the appliance is 
Usted and the bedroom or bathroom has the required volume 
in accordance vs'ith 8.3.2. 

Exception: Direct-vent gas fireplaces. 

9.7.2 Installation. The installation of vented gas fireplaces 
shall comply with the following requirements: 

(1) Listed vented gas fireplaces shall be installed in accor- 
dance with their listing and the manufacturers' instruc- 
tions and where installed in or attached to combustible 
material shall be specifically listed for such installation. 

(2) Unlisted vented gas fireplaces shall not be installed in or 
attached to combustible material. They shall have a clear- 
ance at the sides and rear of not less than 18 in. (460 mm). 
Combustible floors under unlisted vented gas fireplaces 
shall be protected in an approved manner. Unlisted appli- 
ances of other than the direct vent type shall be equipped 
with a draft hood and shall be properly vented in accor- 
dance with Chapter 10. Appliances that use metal, asbestos, 
or ceramic material to direct radiation to the front of the 
appliance shall have a clearance of 36 in. (910 mm) in front 
and, if constructed with a double back of metal or ceramic, 
shall be installed with a minimum clearance of 18 in. 
(460 mm) at the sides and 12 in. (300 mm) at the rear. 

(3) Panels, grilles, and access doors that are required to be 
removed for normal servicing operations shall not be at- 
tached to the building. 

(4) Direct-vent gas fireplaces shall be installed with the vent- 
air intake terminal in the outdoors and in accordance 
with the manufacturers' instructions. 



9.7.3 Combustion and Circulating Air. Combustion and circu- 
lating air shall be provided in accordance with Section 8.3. 

9.8 Non-Recirculating Direct Gas-Fired Industrial Air Heaters. 

9.8.1 Application. Direct gas-fired industrial air heaters of the 
non-recirculating type shall be listed in accordance with ANSI 

Z83.4/CSA 3.7, Non-Recirculating Direct Gas-Fired Industrial Air 
Heaters. 

9.8.2 Prohibited Installations. 

9.8.2.1 Non-recirculating direct gas-fired industrial air heat- 
ers shall not serve any area containing sleeping quarters. 

9.8.2.2 Non-recirculating direct gas-fired industrial air heat- 
ers shall not recirculate room air. 

9.8.3 Installation. 

9.8.3.1 Non-recirculating direct gas-fired industrial air heat- 
ers shall be installed in accordance with the manufacturer's 
instructions. 

9.8.3.2 Non-recirculating direct gas-fired industrial air heat- 
ers shall be installed only in industrial or commercial occu- 
pancies. 

9.8.3.3 Non-recirculating direct gas-fired industrial air heat- 
ers shall be permitted to provide fresh air ventilation. 

9.8.3.4 Non-recirculating direct gas-fired industrial air heaters 
shall be provided with access for removal of burners; replace- 
ment of motors, controls, filters and other working parts; and for 
adjustment and lubrication of parts requiring maintenance. 

9.8.4 Clearance from Combustible Materials. Non-recirculating 
direct gas-fired industrial air heaters shall be installed with a 
clearance from combustible materials of not less than that shown 
on the rating plate and the manufacturer's instructions. 

9.8.5 Air Supply. All air to the non-recirculating direct gas- 
fired industrial air heater shall be ducted directly from out- 
doors. Where outside air dampers or closing louvers are used, 
they shall be verified to be in the open position prior to main 
burner operation. 



Table 9.6.2.3 Free Opening Area of Chimney Damper for Venting Flue Gases 
from Unlisted Decorative Appliances for Installation in Vented Fireplaces 





Minimum Permanent Free Opening (in.^)* 


Chimney 
Height 


8 


13 


20 


29 


39 


51 


64 












(ft) 






Appliance Input Rating (Btu/hr) 






6 


7,800 


14,000 


23,200 


34,000 


46,400 


62,400 


80,000 


8 


8,400 


15,200 


25,200 


37,000 


50,400 


68,000 


86,000 


10 


9,000 


16,800 


27,600 


40,400 


55,800 


74,400 


96,400 


15 


9,800 


18,200 


30,200 


44,600 


62,400 


84,000 


108,800 


20 


10,600 


20,200 


32,600 


50,400 


68,400 


94,000 


122,200 


30 


11,200 


21,600 

— 1 


36,600 


55,200 


76,800 


105,800 


138,600 



For SI units, 1 ft = 0.305 m; 1 in.^ = 645 mm^ 1000 Btu/hr = 0.293 kW. 

*The first six minimum permanent free openings (8 in.^ to 51 in.^) correspond approximately to the cross- 
sectional areas of chimneys having diameters of 3 in. through 8 in., respectively. The 64 in.^ opening corre- 
sponds to the cross-sectional area of standard 8 in. x 8 in. chimney tile. 



2002 Edition 



ANSI Z223. 1-39 



INSTALLATION OF SPECIFIC EQUIPMENT 



54-39 



9.8.6 Atmospheric Vents or Gas Reliefs or Bleeds. Non- 
recirculating direct gas-fired industrial air heaters with valve 
train components equipped with atmospheric vents, gas re- 
liefs, or bleeds shall have their vent lines, gas reliefs, or bleeds 
lead to a safe point outdoors. Means shall be employed on 
these lines to prevent water from entering and to prevent 
blockage from insects and foreign matter. An atmospheric 
vent line shall not be required to be provided on a valve train 
component equipped with a listed vent limiter. 

9.8.7 Relief Openings. The design of the installation shall in- 
clude adequate provisions to permit the non-recirculating di- 
rect gas-fired industrial air heater to operate at its rated airflow 
without over-pressurizing the space served by the heater by 
taking into account the structure's designed infiltration rate, 
properly designed relief openings, or an interlocked powered 
exhaust system, or a combination of these methods. 

9.8.7.1 The structure's designed infiltration rate and the size 
of relief opening (s) shall be determined by approved engi- 
neering methods. 

9.8.7.2 Louver or counterbalanced gravity damper relief 
openings shall be permitted. Where motorized dampers or 
closeable louvers are used they shall be proved to be in their 
open position prior to main burner operation. 

9.8.8 Pluming. Inlet ducting, when used, shall be purged vnth 
at least four air changes prior to an ignition attempt. 

9.9 Recirculating Direct Gas-Fired Industrial Air Heaters. 

9.9.1 Application. Direct gas-fired industrial air heaters of the 
recirculating type shall be listed in accordance with ANSI 
Z83.18, Recirculating Direct Gas-Fired Industrial Air Heaters. 

9.9.2 Prohibited Installations. 

9.9.2.1 Recirculating direct gas-fired industrial air heaters 
shall not serve any area containing sleeping quarters. 

9.9.2.2* Recirculating direct gas-fired industrial air heaters 
shall not recirculate room air in buildings that contain flam- 
mable solids, liquids, or gases, explosive materials, or sub- 
stances that can become toxic when exposed to flame or heat. 

9.9.3 Installation. Installation of direct gas-fired industrial air 
heaters shall comply with the foUowdng requirements: 

(1) Recirculating direct gas-fired industrial air heaters shall 
be installed in accordance with the manufacturer's in- 
structions. 

(2) Recirculating direct gas-fired industrial air heaters shall 
be installed only in industrial or commercial occupancies. 

(3) Recirculating direct gas-fired industrial air heaters shall 
be permitted to provide fresh air ventilation only for the 
amount that exceeds the minimum ventilation air speci- 
fied on the heater's rating plate to maintain the combus- 
tion level created by the heater in the space being served 
by the heater below 25 ppm for carbon monoxide, 3 ppm 
for nitrogen dioxide, and 5000 ppm for carbon dioxide. 
Where gas-powered fork trucks or other fossil fueled 
equipment are utilized in the conditioned space, addi- 
tional ventilation requirements for the facility must be 
addressed separately. 

(4) Recirculating direct gas-fired industrial air heaters shall 
be provided with access for removal of burners; replace- 
ment of motors, controls, filters, and other working parts; 
and for adjustment and lubrication of parts requiring 
maintenance. 



9.9.4 Clearance from Combustible Materials. Recirculating 
direct gas-fired industrial air heaters shall be installed with a 
clearance from combustible materials of not less than that 
shown on the rating plate and the manufacturer's instruc- 
tions. 

9.9.5 Air Supply. Ventilation air to the recirculating direct gas- 
fired industrial air heater shall be ducted direcdy from out- 
doors. Air to the recirculating direct gas-fired industrial air 
heater in excess of the minimum ventilation air specified on 
the heater's rating plate shall be taken from the building, 
ducted directly from outdoors, or a combination of both. 
Where outside air dampers or closing louvers are used, they 
shall be verified to be in the open position prior to main 
burner operation. 

9.9.6 Atmospheric Vents, Gas Reliefs, or Bleeds. Recirculat- 
ing direct gas-fired industrial air heaters with valve train com- 
ponents equipped with atmospheric vents, gas reliefs, or 
bleeds shall have their vent lines, gas reliefs, or bleeds lead to a 
safe point outdoors. Means shall be employed on these lines to 
prevent water from entering and to prevent blockage from 
insects and foreign matter. An atmospheric vent line shall not 
be required to be provided on a valve train component 
equipped with a listed vent limiter. 

9.9.7 Relief Openings. The design of the installation shall in- 
clude adequate provisions to permit the recirculating direct 
gas-fired industrial air heater to operate at its rated airflow 
without over-pressurizing the space served by the heater by 
taking into account the structure's designed infiltration rate, 
properly designed relief openings, an interlocked powered ex- 
haust system, or a combination of these methods. 

9.9.7.1 The structure's designed infiltration rate and the size 
of relief opening(s) shall be determined by approved engi- 
neering methods. 

9.9.7.2 Louver or counterbalanced gravity damper relief 
openings shall be permitted. Where motorized dampers or 
closeable louvers are used, they shall be proved to be in their 
open position prior to main burner operation. 

9.9.8 Pulling. Inlet ducting, when used, shall be purged with 
at least four air changes prior to an ignition attempt. 

9.10 Duct Furnaces. 

9.10.1 Clearances. The installation of duct furnaces shall 
comply with the following clearance requirements: 

(1) Listed duct furnaces shall be installed wdth clearances of 
at least 6 in. (150 mm) between adjacent walls, ceilings, 
and floors of combustible material and the furnace draft 
hood. Furnaces listed for installation at lesser clearances 
shall be installed in accordance with their listings. In no 
case shall the clearance be such as to interfere with com- 
bustion air and accessibility. (See 8.2.1 and Section 8.3.) 

(2) Unlisted duct furnaces shall be installed with clearances 
to combustible material in accordance with the clear- 
ances specified for unlisted furnaces and boilers in Table 
9.2.3(a). Combustible floors under unlisted duct furnaces 
shall be protected in an approved manner. 

9.10.2 Erection of Equipment. Duct furnaces shall be erected 
and firmly supported in accordance with the manufacturers' 
instructions. 

9.10.3 Access Panels. The ducts connected to duct furnaces 
shall have removable access panels on both the upstream and 
downstream sides of the furnace. 



2002 Edition 



54-40 



NATIONAL FUEL GAS CODE 



ANSI Z223. 1-40 



9.10.4 Location of Draft Hood and Controls. The controls, 
combustion air inlet, and draft hoods for duct furnaces shall 
be located outside the ducts. The draft hood shall be located 
in the same enclosure from which combustion air is taken. 

9.10.5 Circulating Air. Where a duct furnace is installed so 
that supply ducts carry air circulated by the furnace to areas 
outside the space containing the furnace, the return air shall 
also be handled by a duct(s) sealed to the furnace casing and 
terminating outside the space containing the furnace. The 
duct furnace shall be installed on the positive-pressure side of 
the circulating air blower. 

9.10.6 Duct Furnaces Used with Refrigeration Systems. 

9.10.6.1 A duct furnace shall not be installed in conjunction 
with a refrigeration coil where circulation of cooled air is pro- 
vided by the blower. 

Exception: Where the blower has sufficient capacity to overcome the 
external static resistance imposed by the duct system, furnace, and the 
cooling coil and the air throughput necessary for heating or cooling, 
whichever is greater. 

9.10.6.2 Duct furnaces used in conjunction v«th cooling 
equipment shall be installed in parallel with or on the up- 
stream side of cooling coils to avoid condensation vsdthin heat- 
ing elements. With a parallel flow arrangement, the dampers 
or other means used to control the flow of air shall be sufifi- 
cientiy tight to prevent any circulation of cooled air through 
the unit. 

Exception: Where the duct furnace has been specifically listed for 
downstream installation. 

9.10.6.3 Where duct furnaces are to be located upstream 
from cooling units, the cooling unit shall be so designed or 
equipped as to not develop excessive temperatures or pres- 
sures. 

9.10.6.4 Where a duct furnace is installed downstream of an 
evaporative cooler or air washer, the heat exchanger shall be 
constructed of corrosion-resistant materials. Stainless steel, 
ceramic-coated steel, and an aluminum-coated steel in which 
the bond between the steel and the aluminum is an iron- 
aluminum alloy are considered to be corrosion resistant. Air 
washers operating vsdth chilled water that deliver air below the 
dew point of the ambient air at the equipment are considered 
as refrigeration systems. 

9.10.7 Installation in Commercial Garages and Aircraft Han- 
gars. Duct furnaces installed in garages for more than three 
motor vehicles or in aircraft hangars shall be of a listed type 
and shall be installed in accordance with 8.1.11 and 8.1.12. 

9.11 Floor Furnaces. 

9.11.1 Installation. The installation of floor furnaces shall 
comply with the following requirements: 

(1 ) Listed floor furnaces shall be installed in accordance with 
their listing and the manufacturers' instructions. 

(2) Unlisted floor furnaces shall not be installed in combus- 
tible floors. 

(3) Thermostats controlling floor furnaces shall not be lo- 
cated in a room or space that can be separated from the 
room or space in which the register of the floor furnace is 
located. 

9.11.2 Temperature Limit Controls. 

9.11.2.1 Listed automatically operated floor furnaces shall be 
equipped with temperature Hmit controls in accordance vsdth 
the terms of their listing. 



9.11.2.2 Unlisted automatically operated floor furnaces shall 
be equipped with a temperature limit control arranged to shut 
off the flow of gas to the burner in the event the temperature 
at the warm air outiet register exceeds 350°F (177°C) above 
room temperature. 

9.11.3 Combustion and Circulating Air. Combustion and cir- 
culating air shall be provided in accordance with Section 8.3. 

9.11.4 Placement. The following provisions apply to furnaces 
that serve one story: 

(1) Floors. Floor furnaces shall not be installed in the floor of 
any doorway, stairway landing, aisle, or passageway of any 
enclosure, public or private, or in an exitv\'ay from any 
such room or space. 

(2) Walls and Comers. The register of a floor furnace with a 
horizontal warm air outlet shall not be placed closer than 
6 in. (150 mm) from the nearest wall. A distance of at least 
18 in. (460 mm) from two adjoining sides of the floor 
furnace register to walls shall be provided to eliminate the 
necessit)' of occupants walking over the warm air dis- 
charge. The remaining sides shall be a minimum of 6 in. 
(150 mm) from a wall. Wall register models shall not be 
placed closer than 6 in. (150 mm) to a corner. 

(3) Draperies. The furnace shall be placed so that a door, drap- 
ery, or similar object cannot be nearer than 12 in. 
(300 mm) to any portion of the register of the furnace. 

9.11.5 Bracing. The space provided for the furnace shall be 
framed with doubled joists and with headers not lighter than 
the joists. 

9.11.6 Support. Means shall be provided to support the fur- 
nace when the floor register is removed. 

9.11.7 Clearance. The lowest portion of the floor furnace 
shall have at least a 6 in. (150 mm) clearance from the general 
ground level. A reduced clearance to a minimum of 2 in. 
(50 mm) is permitted provided the lower 6 in. (150 mm) por- 
tion of the floor furnace is sealed by the manufacturer to pre- 
vent entrance of water. Where these clearances are not 
present, the ground below and to the sides shall be excavated 
to form a "basin-like" pit under the furnace so that the re- 
quired clearance is provided beneath the lowest portion of the 
furnace. A 12 in. (300 mm) clearance shall be provided on all 
sides except the control side, which shall have an 18 in. 
(460 mm) clearance. 

9.11.8 Access. The space in which any floor furnace is in- 
stalled shall be accessible by an opening in the foundation not 
less than 24 in. x 18 in. (610 mm x 460 mm) or by a trapdoor 
not less than 24 in. x 24 in. (610 mm x 610 mm) in any cross- 
section thereof, and a passageway not less than 24 in. x 18 in. 
(610 mm X 460 mm) in any cross-section thereof. 

9.11.9 Seepage Pan. Where the excavation exceeds 12 in. 
(300 mm) in depth or water seepage is likely to collect, a wa- 
tertight copper pan, concrete pit, or other suitable material 
shall be used, unless adequate drainage is provided or the 
equipment is sealed by the manufacturer to meet this condition. 
A copper pan shall be made of not less than 16 oz/ft^ (4.9 kg/ 
m^) sheet copper. The pan shall be anchored in place so as to 
prevent floating, and the walls shall extend at least 4 in. 
(100 mm) above the ground level with at least 6 in. (150 mm) 
clearance on all sides, except the control side, which shall have at 
least 18 in. (460 mm) clearance. 

9.11.10 Wmd Protection. Floor furnaces shall be protected, 
where necessary, against severe wind conditions. 



2002 Edition 



ANSI Z223. 1-41 



INSTALLATION OF SPECIFIC EQUIPMENT 



54-41 



9.11.11 Upper Floor Installations. Listed floor furnaces shall 
be permitted to be installed in an upper floor, provided the 
furnace assembly projects below into a utility room, closet, 
garage, or similar nonhabitable space. In such installations, 
the floor furnace shall be enclosed completely (entirely sepa- 
rated from the nonhabitable space) with means for air intake 
to meet the provisions of Section 8.3, with access for servicing, 
the minimum furnace clearances of 6 in. (150 mm) to all sides 
and bottom, and with the enclosure constructed of pordand ce- 
ment plaster or metal lath or other noncombustible material. 

9.11.12 First Floor Installation. Listed floor furnaces installed 
in the first or ground floors of buildings shall not be required 
to be enclosed unless the basements of these buildings have 
been converted to apartments or sleeping quarters, in which 
case the floor furnace shall be enclosed as specified for upper 
floor installations and shall project into a nonhabitable space. 

9.12 Food Service Equipment, Floor-Mounted. 

9.12.1 Clearance for Listed Equipment. Listed floor-mounted 
food service equipment, such as ranges for hotels and restau- 
rants, deep fat fryers, unit broilers, gas-fired kettles, steam 
cookers, steam generators, and baking and roasting ovens, 
shall be installed at least 6 in. (150 mm) from combustible 
material except that at least a 2 in. (50 mm) clearance shall be 
maintained between a draft hood and combustible material. 
Floor-mounted food service equipment listed for installation 
at lesser clearances shall be installed in accordance with its 
lisfing and the manufacturer's instructions. Equipment de- 
signed and marked "For use only in noncombustible loca- 
tions" shall not be installed elsewhere. 

9.12.2 Clearance for Unlisted Equipment. Unlisted floor- 
mounted food service equipment shall be installed to provide 
a clearance to combustible material of not less than 18 in. 
(460 mm) from the sides and rear of the equipment and from 
the vent connector and not less than 48 in. (1.2 m) above 
cooking tops and at the front of the equipment. Clearances 
for unlisted equipment installed in partially enclosed areas 
such as alcoves shall not be reduced. Reduced clearances for 
unlisted equipment installed in rooms that are not partially 
enclosed shall be in accordance with Table 9.2.3(b). 

9.12.3 Mounting on Combustible Floor. 

9.12.3.1 Listed floor-mounted food service equipment that is 
listed specifically for installation on floors constructed of com- 
bustible material shall be permitted to be mounted on com- 
bustible floors in accordance with its listing and the manufac- 
turer's instructions. 

9.12.3.2 Floor-mounted food service equipment that is not 
listed for mounting on a combustible floor shall be mounted 
in accordance with 9.12.4 or be mounted in accordance with 
one of the following: 

(1) Where the equipment is set on legs that provide not less 
than 18 in. (46() mm) open space under the base of the 
equipment or where it has no burners and no portion of 
any oven or broiler within 18 in. (460 mm) of the floor, it 
shall be permitted to be mounted on a combustible floor 
without special floor protection, provided there is at least 
one sheet metal baffle between the burner and the floor. 

(2) Where the equipment is set on legs that provide not less 
than 8 in. (200 mm) open space under the base of the 
equipment, it shall be permitted to be mounted on com- 
bustible floors, provided the floor under the equipment is 



protected with not less than % in. (9.5 mm) insulating 
millboard covered with sheet metal not less than 
0.0195 in. (0.5 mm) thick. The preceding specified floor 
protection shall extend not less than 6 in. (150 mm) be- 
yond the equipment on all sides. 

(3) Where the equipment is set on legs that provide not less 
than 4 in. (100 mm) under the base of the equipment, it 
shall be permitted to be mounted on combustible floors, 
provided the floor under the equipment is protected with 
hollow masonry not less than 4 in. (100 mm) in thickness 
covered with sheet metal not less than 0.0195 in. 
(0.5 mm) thick. Such masonry courses shall be laid with 
ends unsealed and joints matched in such a way as to pro- 
vide for free circulation of air through the masonry. 

(4) Where the equipment does not have legs at least 4 in. 
(100 mm) high, it shall be permitted to be mounted on 
combustible floors, provided the floor under the equip- 
ment is protected by two courses of 4 in. (100 mm) hollow 
clay tile, or equivalent, with courses laid at right angles 
and with ends unsealed and joints matched in such a way 
as to provide for free circulation of air through such ma- 
sonry courses, and covered with steel plate not less than 
Vie in. (4.8 mm) in thickness. 

9.12.4 Mounting on Noncombustible Floor. Listed floor- 
mounted food service equipment that is designed and marked 
"For use only in noncombustible locations" shall be mounted 
on floors of noncombustible construction with noncombus- 
tible flooring and surface finish and with no combustible ma- 
terial against the underside thereof, or on noncombustible 
slabs or arches having no combustible material against the 
underside thereof. Such construction shall in all cases extend 
not less than 12 in. (300 mm) beyond the equipment on all 
sides. 

9.12.5 Combustible Material Adjacent to Cooking Top. Any 

portion of combustible material adjacent to a cooking top sec- 
tion of a food service range, even though listed for close-to- 
wall installation, that is not shielded from the wall by a high 
shelf, warming closet, and so on, shall be protected as speci- 
fied in 9.12.2 for a distance of at least 2 ft (0.6 m) above the 
surface of the cooking top. 

9.12.6 For Use with Casters. Floor-mounted equipment with 
casters shall be listed for such construction and shall be in- 
stalled in accordance with their listing and the accompanying 
instructions for limiting the movement of the equipment to 
prevent strain on the connection. 

9.12.7 Level Installation. Floor-mounted food service equip- 
ment shall be installed level on a firm foundation. 

9.12.8* Ventilation. Means shall be provided to properly venti- 
late the space in which food service equipment is installed to 
permit proper combustion of the gas. 

9.13 Food Service Equipment Counter Appliances. 

9.13.1 Vertical Clearance. A vertical distance of not less than 
48 in. (1.2 m) shall be provided between the top of all food 
service hot plates and griddles and combustible material. 

9.13.2 Clearance for Listed Appliances. Listed food service 
counter appliances such as hot plates and griddles, food and 
dish warmers, and coffee brewers and urns, where installed on 
combustible surfaces, shall be set on their own bases or legs 
and shall be installed with a minimum horizontal clearance of 
6 in. (150 mm) from combustible material, except that at least 
a 2 in. (50 mm) clearance shall be maintained between a draft 



2002 Edition 



54-42 



NATIONAL FUEL GAS CODE 



ANSI Z223. 1-42 



hood and combustible material. Food service counter appli- 
ances listed for installation at lesser clearances shall be in- 
stalled in accordance with their listing and the manufacturers' 
instructions. 

9.13.3 Clearance for Unlisted Appliances. Unlisted food ser- 
vice hot plates and griddles shall be installed vsdth a horizontal 
clearance from combustible material of not less than 18 in. 
(460 mm). Unlisted gas food service counter appliances, in- 
cluding coffee brewers and urns, waffle bakers, and hot water 
immersion sterilizers, shall be installed with a horizontal clear- 
ance from combustible material of not less than 12 in. 
(300 mm). Reduced clearances for gas food service counter 
appliances shall be in accordance with Table 9.2.3(b). Un- 
listed food and dish warmers shall be installed with a horizon- 
tal clearance from combustible material of not less than 6 in. 
(150 mm). 

9.13.4 Mounting of Unlisted Appliances. Unlisted food ser- 
vice counter appliances shall not be set on combustible mate- 
rial unless they have legs that provide not less than 4 in. 
(100 mm) of open space below the burners and the combus- 
tible surface is protected with insulating millboard at least 
V4 in. (6 mm) thick covered with sheet metal not less than 
0.0122 in. (0.3 mm) thick, or with equivalent protection. 

9.14 Hot Plates and Laundry Stoves. 

9.14.1 Listed domestic hot plates and laundry stoves installed 
on combustible surfaces shall be set on their ov«i legs or bases. 
They shall be installed with minimum horizontal clearances of 
6 in. (150 mm) from combustible material. 

9.14.2 Unlisted domestic hot plates and laundry stoves shall 
be installed with horizontal clearances to combustible mate- 
rial of not less than 12 in. (300 mm). Combustible surfaces 
under unlisted domestic hot plates and laundry stoves shall be 
protected in an approved manner. 

9.14.3 The vertical distance between tops of all domestic hot 
plates and laundry stoves and combustible material shall be at 
least 30 in. (760 mm). 

9.15 Household Cooking Appliances. 

9.15.1 Floor-Mounted Units. 

9.15.1.1 Clearance from Combustible Material. The clear- 
ances specified as follows shall not interfere with combustion 
air, accessibility for operation, and servicing: 

( 1 ) Listed floor-mounted household cooking appliances, where 
installed on combustible floors, shall be set on their own 
bases or legs and shall be installed in accordance with their 
listing and the manufacturers' instructions. 

(2) Listed household cooking appliances with listed gas room 
heater sections shall be installed so that the warm air dis- 
charge side shall have a minimum clearance of 18 in. 
(460 mm) from adjacent combustible material. A mini- 
mum clearance of 36 in. (910 mm) shall be provided be- 
tween the top of the heater section and the bottom of 
cabinets. 

(3) Listed household cooking appliances that include a solid 
or liquid fuel-burning section shall be spaced from com- 
bustible material and otherwise installed in accordance 
with the standards applying to the supplementary fuel sec- 
tion of the appliance. 

(4) Unlisted floor-mounted household cooking appliances 
shall be installed with at least a 6 in. (150 mm) clearance 
at the back and sides to combustible material. Combus- 



tible floors under unlisted appliances shall be protected 
in an approved manner. 

9.15.1.2 Vertical Clearance Above Cooking Top. Household 
cooking appliances shall have a vertical clearance above the 
cooking top of not less than 30 in. (760 mm) to combustible 
material or metal cabinets. A minimum clearance of 24 in. 
(610 mm) is permitted when one of the following is installed: 

(1) The underside of the combustible material or metal cabi- 
net above the cooking top is protected with not less than 
Vi in. (6 mm) insulating millboard covered with sheet 
metal not less than 0.0122 in. (0.3 mm) thick. 

(2) A metal ventilating hood of sheet metal not less than 
0.0122 in. (0.3 mm) thick is installed above the cooking 
top with a clearance of not less than Vi in. (6 mm) be- 
tween the hood and the underside of the combustible 
material or metal cabinet, and the hood is at least as wide 
as the appliance and is centered over the appliance. 

(3) A listed cooking appliance or microwave oven is installed 
over a listed cooking appliance and will conform to the 
terms of the upper appliance's listing and the manufac- 
turer's instructions. 

9.15.1.3 Level Installation. Cooking appliances shall be in- 
stalled so that the cooking top or oven racks are level. 

9.15.2 Built-in Units. 

9.15.2.1 Installation. Listed built-in household cooking appli- 
ances shall be installed in accordance with their listing and the 
manufacturer's instructions. The installation shall not inter- 
fere with combustion air, accessibility for operation, and ser- 
vicing. Unlisted built-in household cooking appliances shall 
not be installed in, or adjacent to, combustible material. 

9.15.2.2 Vertical Clearance. Built-in top (or surface) cooking 
appliances shall have a vertical clearance above the cooking 
top of not less than 30 in. (760 mm) to combustible material 
or metal cabinets. A minimum clearance of 24 in. (610 mm) is 
permitted when one of the foUov^dng is installed: 

(1) The underside of the combustible material or metal cabi- 
net above the cooking top is protected with not less than 
14 in. (6 mm) insulating millboard covered with sheet 
metal not less than 0.0122 in. (0.3 mm) thick. 

(2) A metal ventilating hood of sheet metal not less than 
0.0122 in. (0.3 mm) thick is installed above the cooking 
top with a clearance of not less than Vk in. (6 mm) be- 
tween the hood and the underside of the combustible 
material or metal cabinet, and the hood is at least as wide 
as the appliance and is centered over the appliance. 

(3) A listed cooking appliance or microwave oven is installed 
over a listed cooking appliance and will conform to the 
terms of the upper appliance's listing and the manufac- 
turer's instructions. 

9.15.2.3 Horizontal Clearance. The minimum horizontal dis- 
tance from the center of the burner head(s) of a listed top (or 
surface) cooking appliance to vertical combustible walls ex- 
tending above the top panel shall be not less than that dis- 
tance specified by the permanent marking on the appliance. 

9.15.2.4 Level Installation. Built-in household cooking appli- 
ances shall be installed so that the cooking top, broiler pan, or 
oven racks are level. 

9.16 Illuminating Appliances. 

9.16.1 Clearances for Listed Appliances. Listed illuminating 
appliances shall be installed in accordance with their listing 
and the manufacturers' instructions. 



2002 Edition 



ANSI Z223. 1-43 



INSTALLATION OF SPECIFIC EQUIPMENT 



54-43 



9.16.2 Clearances for Unlisted Appliances. 

9.16.2.1 Enclosed Type. Clearance shall comply with the 
following: 

(1) Unlisted enclosed illuminating appliances installed out- 
doors shall be installed with clearances in any direction 
from combustible material of not less than 12 in. 
(300 mm). 

(2) Unlisted enclosed illuminating appliances installed in- 
doors shall be installed with clearances in any direction 
from combustible material of not less than 18 in. 
(460 mm). 

9.16.2.2 Open-Flame Type. Clearance shall comply with the 
following: 

(1) Unlisted open-flame illuminating appliances installed 
outdoors shall have clearances from combustible material 
not less than that specified in Table 9.16.2.2. The distance 
from ground level to the base of the burner shall be a 
minimum of 7 ft (2.1 m) where installed within 2 ft (0.6 m) 
of walkways. Lesser clearances shall be permitted to be used 
where acceptable to the authority having jurisdiction. 

(2) Unlisted open-flame illuminating appliances installed 
outdoors shall be equipped with a limiting orifice or 
other limiting devices that will maintain a flame height 
consistent with the clearance from combustible material, 
as given in Table 9.16.2.2. 

(3) Appliances designed for flame heights in excess of 30 in. 
(760 mm) shall be permitted to be installed if acceptable 
to the authority having jurisdiction. Such appliances shall 
be equipped with a safety shutoflF device or automatic ig- 
nition. 

(4) Unlisted open-flame illuminating appliances installed in- 
doors shall have clearances from combustible material ac- 
ceptable to the authority having jurisdiction. 

Table 9.16.2.2 Clearances for Unlisted Outdoor Open-Flame 
Illuminating Appliances 



Flame Height 

Above Burner 

Head 

(in.) 



Minimum Clearance from 
Combustible Material (ft)* 



Horizontal 



Vertical 



12 
18 
24 
30 



10 
12 



For SI units, I in. = 25.4 mm; 1 ft = 0.305 m. 
^Measured from the nearest portion of the burner head. 

9.16.3 Mounting on BuUdings. Illuminating appliances de- 
signed for wall or ceiling mounting shall be securely attached 
to substantial structures in such a manner that they are not 
dependent on the gas piping for support. 

9.16.4 Mounting on Posts. Illuminating appliances designed 
for post mounting shall be securely and rigidly attached to a 
post. Posts shall be rigidly mounted. The strength and rigidity 
of posts greater than 3 ft (0.9 m) in height shall be at least 
equivalent to that of a 2V2 in. (64 mm) diameter post con- 
structed of 0.064 in. (1.6 mm) thick steel or a 1 in. Schedule 40 
steel pipe. Posts 3 ft (0.9 m) or less in height shall not be 



smaller than a % in. Schedule 40 steel pipe. Drain openings 
shall be provided near the base of posts where there is a possi- 
bility of water collecting inside them. 

9.16.5 Gas Appliance Pressure Regulators. Where a gas appli- 
ance pressure regulator is not supplied with an illuminating 
appliance and the service line is not equipped with a service 
pressure regulator, an appliance pressure regulator shall 
be installed in the line serving one or more illuminating 
appliances. 

9.17 Incinerators, Commercial-Industrial. Commercial-indus- 
trial-type incinerators shall be constructed and installed in accor- 
dance with NFPA 82, Standard on Incinerators and Waste and Linen 
Handling Systems and Equipment. 

9.18 Infrared Heaters. 

9.18.1 Support. Suspended-type infrared heaters shall be 
fixed in position independent of gas and electric supply lines. 
Hangers and brackets shall be of noncombustible material. 
Heaters subject to vibration shall be provided with vibration- 
isolating hangers. 

9.18.2 Clearance. The installation of infrared heaters shall 
meet the follov«ng clearance requirements: 

( 1 ) Listed heaters shall be installed with clearances from com- 
bustible material in accordance with their listing and the 
manufacturers' instructions. 

(2) Unlisted heaters shall be installed in accordance with 
clearances from combustible material acceptable to the 
authority havingjurisdiction. 

(3) In locations used for the storage of combustible materials, 
signs shall be posted to specify the maximum permissible 
stacking height to maintain required clearances from the 
heater to the combustibles. 

9. 18.3 Combustion and Ventilation Air. 

9.18.3.1 Where unvented infrared heaters are used, natural 
or mechanical means shall be provided to supply and exhaust 
at least 4 ft^/min/1000 Btu/hr (0.38 m^/min/kW) input of 
installed heaters. 

9.18.3.2 Exhaust openings for removing flue products shall 
be above the level of the heaters. 

9.18.4 Installation in Conmiercial Garages and Aircraft Han- 
gars. Overhead heaters installed in garages for more than 
three motor vehicles or in aircraft hangars shall be of a listed 
type and shall be installed in accordance with 8.1.11 and 
8.1.12. 

9.19 Open-Top Broiler Units. 

9.19.1 Listed Units. Listed open-top broiler units shall be in- 
stalled in accordance with their listing and the manufacturers' 
instructions. 

9.19.2 Unlisted Units. Unlisted open-top broiler units shall be 
installed in accordance with the manufacturers' instructions 
but shall not be installed in combustible material. 

9.19.3 Protection Above Domestic Units. Domestic open-top 
broiler units shall be provided with a metal ventilating hood 
not less than 0.0122 in. (0.3 mm) thick with a clearance of not 
less than Vi in. (6 mm) between the hood and the underside of 
combustible material or metal cabinets. A clearance of at least 
24 in. (610 mm) shall be maintained between the cooking top 
and the combustible material or metal cabinet, and the hood 
shall be at least as wide as the open-top broiler unit and cen- 



2002 Edition 



54-44 



NATIONAL FUEL GAS CODE 



ANSI Z223. 1-44 



tered over the unit. Listed domestic open-top broiler units 
incorporating an integral exhaust system and listed for use 
without a ventilating hood need not be provided with a venti- 
lating hood if installed in accordance with 9.15.L2(1). 

9.19.4 Commercial Units. Commercial open-top broiler units 
shall be provided with ventilation in accordance with NFPA96, 
Standard for Ventilation Control and Fire Protection of Commercial 
Cooking Operations. 

9.20 Outdoor Cooking Appliances. 

9.20.1 Listed Units. Listed outdoor cooking appliances shall 
be installed in accordance with their listing and the manufac- 
turers' instructions. 

9.20.2 Unlisted Units. Unlisted outdoor cooking appliances 
shall be installed outdoors with clearances to combustible ma- 
terial of not less than 36 in. (910 mm) at the sides and back 
and not less than 48 in. (1220 mm) at the front. In no case 
shall the appliance be located under overhead combustible 
construction. 

9.21 Pool Heaters. 

9.21.1 Location. A pool heater shall be located or protected so 
as to minimize accidental contact of hot surfaces by persons. 

9.21.2 Clearance. The installation of pool heaters shall meet 
the following requirements: 

(1) In no case shall the clearances be such as to interfere With 
combustion air, draft hood or vent terminal clearance 
and relief, and accessibility for servicing. 

(2) A listed pool heater shall be installed in accordance with 
its listing and the manufacturer's instructions. 

(3) An unlisted pool heater shall be installed with a minimum 
clearance of 12 in. (300 mm) on all sides and the rear. A 
combustible floor under an unlisted pool heater shall be 
protected in an approved manner. 

9.21.3 Temperature- or Pressure-Limiting Devices. 

9.21.3.1 An unlisted pool heater shall be provided v«th over- 
temperature protection or overtemperature and overpressure 
protection by means of an approved device (s). 

9.21.3.2 Where a pool heater is provided with overtempera- 
ture protection only and is installed with any device in the 
discharge line of the heater that can restrict the flow of water 
from the heater to the pool (such as a check valve, shutoff 
valve, therapeutic pool valving, or flow nozzles), a pressure 
relief valve shall be installed either in the heater or between 
the heater and the restrictive device. 

9.21.4 Bypass Valves. Where an integral bypass system is not 
provided as a part of the pool heater, a bypass line and valve 
shall be installed between the inlet and outlet piping for use in 
adjusting the flow of water through the heater. 

9.21.5 Venting. A pool heater listed for outdoor installation 
shall be installed with the venting means supplied by the 
manufacturer and in accordance with the manufacturer's in- 
structions. (See 10.2.5, 10.2.6, 10.3.4, and Section 10.8.) 

9.22 Refrigerators. 

9.22.1 Clearance. Refrigerators shall be provided with clear- 
ances for ventilation at the top and back in accordance with 
the manufacturers' instructions. Where such instructions are 
not available, at least 2 in. (50 mm) shall be provided between 



the back of the refrigerator and the wall and at least 12 in. 
(300 mm) above the top. 

9.22.2 Venting or Ventilating Kits Approved for Use with a 
Refrigerator. Where an accessory kit is used for conveying air 
for burner combustion or unit cooling to the refrigerator 
from areas outside the room in which it is located, or for con- 
veying combustion products diluted with air-containing waste 
heat from the refrigerator to areas outside the room in which 
it is located, the kit shall be installed in accordance with the 
refrigerator manufacturer's instructions. 

9.23 Room Heaters. 

9.23.1* Prohibited Installations. Unvented room heaters shall 
not be installed in bathrooms or bedrooms. 

Exception No. 1: Where approved by the authority having jurisdic- 
tion, one listed wall-mounted unvented room heater equipped with 
an oxygen depletion safety shutoff system shall be permitted to be 
installed in a bathroom provided that the input rating shall not 
exceed 6000 Btu/hr (1 760 W/hr) and combustion and ventilation 
air is provided as specified in 9.1.2. 

Exception No. 2: Where approved by the authority having jurisdiction, 
one listed wall-mounted unvented room heater equipped with an oxygen 
depletion safety shutoff system shall be permitted to be installed in a bed- 
room provided that the input rating shall not exceed 10,000 Btu/hr 
(2930 W/hr) and combustion and ventilation air is provided as specified 
in 91.2. 

9.23.2 Installations in Institutions. Room heaters shall not be 
installed in the following occupancies: 

(1) Residential board and care 

(2) Health care 

9.23.3 Clearance. A room heater shall be placed so as not to 
cause a hazard to walls, floors, curtains, furniture, doors when 
open, and so on, and to the free movements of persons within 
the room. Heaters designed and marked "For use in noncom- 
bustible fireplace only" shall not be installed elsewhere. Listed 
room heaters shall be installed in accordance with their listings 
and the manufacturers' instructions. In no case shall the clear- 
ances be such as to interfere with combustion air and accessibil- 
ity. Unlisted room heaters shall be installed with clearances from 
combustible material not less than the following: 

(1) Circulating Type. Room heaters having an outer jacket sur- 
rounding the combustion chamber, arranged with open- 
ings at top and bottom so that air circulates between the 
inner and outer jacket, and without openings in the outer 
jacket to permit direct radiadon, shall have clearance at 
sides and rear of not less than 12 in. (300 mm). 

(2) Radiating Type. Room heaters other than those of the cir- 
culating type described in 9.23.3(1) shall have clearance 
at sides and rear of not less than 18 in. (460 mm), except 
that heaters that make use of metal, asbestos, or ceramic 
material to direct radiation to the front of the heater shall 
have a clearance of 36 in. (910 mm) in front and, if con- 
structed with a double back of metal or ceramic, shall be 
permitted to be installed with a clearance of 18 in. 
(460 mm) at sides and 12 in. (300 mm) at rear. Combus- 
tible floors under unlisted room heaters shall be pro- 
tected in an approved manner. 

9.23.4 Wall-Type Room Heaters. Wall-type room heaters shall 
not be installed in or attached to walls of combustible material 
unless listed for such installation. 



2002 Edition 



ANSI Z223. 1-45 



INSTALLATION OF SPECIFIC EQUIPMENT 



54-45 



9.24 Stationary Gas Engines. The installation of gas engines 
shall conform with NFPA37, Standard for the Installation and Use 
of Stationary Combustion Engines and Gas Turbines. 

9.25 Gas-Fired Toilets. 

9.25.1 Clearance. A listed gas-fired toilet shall be installed in 
accordance with its listing and the manufacturer's instruc- 
tions, provided that the clearance shall in any case be suffi- 
cient to afford ready accessibility for use, cleanout, and neces- 
sary servicing. 

9.25.2 Mounting. Listed gas-fired toilets installed on combus- 
tible floors shall be listed for such installation. 

9.25.3 Installation. Vents or vent connectors that are capable 
of being contacted during casual use of the room in which the 
toilet is installed shall be protected or shielded to prevent such 
contact. 

9.26 Unit Heaters. 

9.26.1 Support. Suspended-type unit heaters shall be safely 
and adequately supported with due consideration given to 
their weight and vibration characteristics. Hangers and brack- 
ets shall be of noncombustible material. 

9.26.2 Clearance. 

9.26.2.1 Suspended-Type Unit Heaters. Suspended-type unit 
heaters shall meet the following requirements: 

( 1 ) A listed unit heater shall be installed with clearances from 
combustible material of not less than 18 in. (460 mm) at 
the sides, 12 in. (300 mm) at the bottom, and 6 in. 
(150 mm) above the top where the unit heater has an 
internal draft hood, or 1 in. (25 mm) above the top of the 
sloping side of a vertical draft hood. A unit heater listed 
for reduced clearances shall be installed in accordance 
with its listing and the manufacturer's instructions. 

(2) Unlisted unit heaters shall be installed with clearances to 
combustible material of not less than 18 in. (460 mm). 

(3) Clearances for servicing shall be in accordance with the 
manufacturers' recommendations contained in the instal- 
lation instructions. 

9.26.2.2 Floor-Mounted-Type Unit Heaters. Floor-mounted- 
type unit heaters shall meet the following requirements: 

( 1 ) A listed unit heater shall be installed with clearances from 
combustible material at the back and one side only of not 
less than 6 in. (150 mm). Where the flue gases are vented 
horizontally, the 6 in. (150 mm) clearance shall be mea- 
sured from the draft hood or vent instead of the rear wall 
of the unit heater. A unit heater listed for reduced clear- 
ances shall be installed in accordance with its listing and 
the manufacturer's instructions. 

(2) Floor-mounted-type unit heaters installed on combustible 
floors shall be listed for such installation. 

(3) Combustible floors under unlisted floor-mounted unit 
heaters shall be protected in an approved manner. 

(4) Clearances for servicing shall be in accordance with the 
manufacturers' recommendations contained in the instal- 
lation instructions. 

9.26.3 Combustion and Circulating Air. Combustion and cir- 
culating air shall be provided in accordance with Section 8.3. 

9.26.4 Ductwork. A unit heater shall not be attached to a 
warm air duct system unless listed and marked for such in- 
stallation. 



9.26.5 Installation in Commercial Garages and Aircraft Han- 
gars. Unit heaters installed in garages for more than three 
motor vehicles or in aircraft hangars shall be of a listed type 
and shall be installed in accordance with 8.1.11 and 8.1.12. 

9.27 Wall Furnaces. 

9.27.1 Installation. 

9.27.1.1 Listed wall furnaces shall be installed in accordance 
with their listing and the manufacturers' instructions. Wall fur- 
naces installed in or attached to combustible material shall be 
listed for such installation. 

9.27.1.2 Unlisted wall furnaces shall not be installed in or 
attached to combustible material. 

9.27.1.3 Vented wall furnaces connected to a Type B-W gas 
vent system listed only for a single story shall be installed only 
in single-story buildings or the top story of multistory build- 
ings. Vented wall furnaces connected to a Type B-W gas vent 
system listed for installation in multistory buildings shall be 
permitted to be installed in single-story or multistory build- 
ings. Type B-W gas vents shall be attached directly to a solid 
header plate that serves as a firestop at that point and that 
shall be permitted to be an integral part of the vented wall 
furnace. The stud space in which the vented wall furnace is 
installed shall be ventilated at the first ceiling level by installa- 
tion of the ceiling plate spacers furnished with the gas vent. 
Firestop spacers shall be installed at each subsequent ceiling 
or floor level penetrated by the vent. (SeeFigure 9.27.1.3 for Type 
B-W gas vent installation.) 



Installation of B-W gas 
vent for each subsequent 
ceiling or floor level of 
multistory buildings 




Firestop spacers supplied 
by manufacturer of B-W 
gas vent 



Plate cut away to provide 
passage of B-W gas vent 



Installation of B-W gas 
vent for single-story 
buildings or for first-floor 
or multistory buildings 



Header plate of 
vented wall furnace 
(also acts as firestop) 




Nail firestop 
spacer securely 



Ceiling plate spacers to center 
B-W gas vent in stud space — 
nail securely at both ends 



Plate cut away for full width of 
stud space to provide ventilation 

-Studs on 16 in. (410 mm) 
centers 



Sheet metal screw 
base plate to header 



Use manufacturer's 
method of fastening 
pipe to base plate 

nCURE 9.27.1.3 InstaUation of Type B-W Gas Vents for 
Vented Wall Furnaces. 



2002 Edition 



54-46 



NATIONAL FUEL GAS CODE 



ANSI Z223. 1-46 



9.27.1.4 Direct-vent wall furnaces shall be installed with the 
vent-air intake terminal in the outside atmosphere. The thick- 
ness of the walls on which the furnace is mounted shall be 
within the range of wall thickness marked on the furnace and 
covered in the manufacturers' installation instructions. 

9.27.1.5 Panels, grilles, and access doors that are required to 
be removed for normal servicing operations shall not be at- 
tached to the building. (For additional information on the venting 
of wall furnaces, see Chapter 10.) 

9.27.2 Location. Wall furnaces shall be located so as not to 
cause a hazard to walls, floors, curtains, furniture, or doors. 
Wall furnaces installed between bathrooms and adjoining 
rooms shall not circulate air from bathrooms to other parts of 
the building. 

9.27.3 Combustion and Circulating Air. Combustion and cir- 
culating air shall be provided in accordance with Section 8.3. 

9.28 Water Heaters. 

9.28.1 Location. 

9.28.1.1 Water heater installations in bedrooms and bath- 
rooms shall comply with one of the following: 

(1) Water heater shall be installed in a closet equipped with a 
weather-stripped door with a self-closing device, and all 
combustion air shall be obtained from the outdoors in 
accordance with 8.3.3. 

(2) Water heater shall be of the direct-vent type. 

9.28.1.2 Water heaters of other than the direct-vent type shall 
be located as close as practical to the chimney or gas vent. 

9.28.2 Clearance. 

9.28.2.1 The clearances shall not be such as to interfere with 
combustion air, draft hood clearance and relief, and accessibility 
for servicing. Listed water heaters shall be installed in accordance 
with their listing and the manufacturers' instructions. 

9.28.2.2 Unlisted water heaters shall be installed with a clear- 
ance of 12 in. (300 mm) on all sides and rear. Combustible 
floors under unlisted water heaters shall be protected in an 
approved manner. 

9.28.3 Pressvu^-Limiting Devices. A water heater installation 
shall be provided with overpressure protection by means of an 
approved, listed device installed in accordance with the terms 
of its listing and the manufacturer's instructions. The pressure 
setting of the device shall exceed the water service pressure 
and shall not exceed the maximum pressure rating of the wa- 
ter heater. 

9.28.4 Temperature-Limiting Devices. A water heater installa- 
tion or a hot water storage vessel installation shall be provided 
with overtemperature protection by means of an approved, 
listed device installed in accordance with the terms of its list- 
ing and the manufacturers' instructions. 

9.28.5 Temperature, Pressure, and Vacuum Relief Devices. 

The installation of temperature, pressure, and vacuum relief 
devices or combinations thereof, and automatic gas shutoflF 
devices, shall be in accordance with the terms of their listing 
and the manufacturers' instructions. A shutofiF valve shall not 
be placed between the relief valve and the water heater or on 
discharge pipes between such valves and the atmosphere. The 
hourly Btu discharge capacity or the rated steam relief capac- 
ity of the device shall not be less than the input rating of the 
water heater. 



9.28.6 Automatic Instantaneous Type: Cold Water Supply. 

The water supply to an automatic instantaneous water heater 
that is equipped with a water flow-actuated control shall be 
such as to provide sufficient pressure to properly operate the 
control when water is drawn from the highest faucet served by 
the heater. 

9.28.7 Circulating Tank Types. 

9.28.7.1 Connection to Tank. The method of connecting the 
circulating water heater to the tank shall provide proper circu- 
lation of water through the heater and permit a safe and use- 
ful temperature of water to be drawn from the tank. (See Figure 
9.28.7.1.) 



Limit control or 
temperature 
relief valve 



Hot water -<—c 



Best return 
location 

/ 




Cold 
jQe=j-<— water 
inlet 

FIGURE 9.28.7. 1 Typical Gravity Circulating Tank-Type 
Installation. 



9.28.7.2 Size of Water Circulating Piping. The size of the wa- 
ter circulating piping shall conform with the size of the water 
connections of the heater. 

9.28.7.3 Sediment Drain. A suitable water valve or cock, 
through which sediment can be drawn off or the tank emp- 
tied, shall be installed at the bottom of the tank. 

9.28.8* Antisiphon Devices. Means acceptable to the authority 
having jurisdiction shall be provided to prevent siphoning in 
any water heater or any tank to which a circulating water 
heater that incorporates a cold water inlet tube is attached. 

9.29 Compressed Natural Gas (CNG) Vehicular Fuel Systems. 

The installation of compressed natural gas (CNG) fueling 
(dispensing) systems shall conform with NFPA 52, Compressed 
Natural Gas (CNG) Vehicular Fuel Systems Code. 

9.30 Appliances for Installation in Manufactured Housing. 

Appliances installed in manufactured housing after the initial 
sale shall be listed for installation in manufactured housing, or 
approved, and shall be installed in accordance with the re- 
quirements of this code and the manufacturers' installation 
instructions. Appliances installed in the living space of manu- 
factured housing shall be in accordance with the require- 
ments of Section 8.3. 

9.31 Fuel Cell Power Plants. Fuel cell power plants with a 
power output of less than 50 kW shall be listed and installed in 
accordance with the manufacturer's instructions. Fuel cell 
power plants with a power output of greater than 50 kW shall 
be installed in accordance with NFPA 853, Standard for the In- 
stallation of Stationary Fuel Cell Power Plants. 



2002 Edition 



ANSI Z223.1-47 



VENTING OF EQUIPMENT 



54-47 



Chapter 10 Venting of Equipment 

10.1 General. This chapter recognizes that the choice of vent- 
ing materials and the methods of installation of venting sys- 
tems are dependent on the operating characteristics of the gas 
utilization equipment. The operating characteristics of vented 
gas utilization equipment can be categorized with respect to 

(1) positive or negative pressure within the venting system and 

(2) whether or not the equipment generates flue or vent gases 
that can condense in the venting system. See Section 3.3 for 
the definition of these vented appliance categories. 

10.2 Specification for Venting. 

10.2.1 Connection to Venting Systems. Except as permitted in 

10.2.2 through 10.2.6, all gas utilization equipment shall be 
connected to venting systems. 

10.2.2 Equipment Not Required to Be Vented. The following 
equipment shall not be required to be vented: 

(1) Listed ranges 

(2) Built-in domestic cooking units listed and marked for 
optional venting 

(3) Listed hot plates and listed laundry stoves 

(4) Listed Type 1 clothes dryers exhausted in accordance 
with Section 9.4 

(5) A single listed booster-type (automatic instantaneous) 
water heater, when designed and used solely for the sani- 
dzing rinse requirements of a dishwashing machine, pro- 
vided that the equipment is installed, with the draft hood 
in place and unaltered, if a draft hood is required, in a 
commercial kitchen having a mechanical exhaust sys- 
tem; where installed in this manner, the draft hood out- 
let shall not be less than 36 in. (910 mm) vertically and 
6 in. (150 mm) horizontally from any surface other than 
the equipment. 

(6) Listed refrigerators 

(7) Counter appliances 

(8) Room heaters listed for unvented use (see 9.23.1 and 
9.23.2) 

(9) Direct gas-fired make-up air heaters 

(10) Other equipment listed for unvented use and not pro- 
vided with flue collars 

(11) Specialized equipment of limited input such as labora- 
tory burners or gas lights. Where any or all of the equip- 
ment in 10.2.2(5) through (11) is installed so the aggre- 
gate input rating exceeds 20 Btu/hr/ft^ (207 W/m ) of 
room or space in which it is installed, one or more shall 
be provided v«th venting systems or other approved 
means for removing the vent gases to the outside atmo- 
sphere so the aggregate input rating of the remaining 
unvented equipment does not exceed 20 Btu/hr/ft 
(207 W/m^) . Where the calculation includes the volume 
of an adjacent room or space, the room or space in 
which the equipment is installed shall be directly con- 
nected to the adjacent room or space by a doorway, arch- 
way, or other opening of comparable size that cannot be 
closed. 

10.2.3* VentUating Hoods. Ventilating hoods and exhaust sys- 
tems shall be permitted to be used to vent gas utilization 
equipment installed in commercial applications {see 10.3.3) 
and to vent industrial equipment, particularly where the pro- 
cess itself requires fume disposal. (See 8.1.6 and 8.1.9.) 

10.2.4 Well-VentUated Spaces. The operation of industrial gas 
utilization equipment such that its flue gases are discharged di- 
recdy into a large and well-ventilated space shall be permitted. 



10.2.5 Direct-Vent Equipment. Listed direct-vent gas utiliza- 
tion equipment shall be considered properly vented where 
installed in accordance v«th the terms of its listing, the manu- 
facturers' instructions, and 10.8.3. 

10.2.6 Equipment with Integral Vents. Gas utilization equip- 
ment incorporating integral venting means shall be consid- 
ered properly vented where installed in accordance with its 
listing, the manufacturers' instructions, and 10.8.1 and 10.8.2. 

10.3 Design and Construction. 

10.3.1 Minimum Safe Performance. A venting system shall be 
designed and constructed so as to develop a positive flow ad- 
equate to remove flue or vent gases to the outside atmosphere. 

10.3.2 Equipment Draft Requirements. A venting system shall 
satisfy the draft requirements of the equipment in accordance 
v«th the manufacturer's instructions. 

10.3.3 Design and Construction. Gas utilization equipment 
required to be vented shall be connected to a venting system 
designed and installed in accordance with the provisions of 
Sections 10.4 through 10.15. 

10.3.4 Mechanical Draft Systems. 

10.3.4.1 Mechanical draft systems shall be listed and shall be 
installed in accordance vsdth the terms of their listing and both 
the appliance and the mechanical draft system manufacturers' 
instructions. 

10.3.4.2 Gas utilization equipment requiring venting shall be 
permitted to be vented by means of mechanical draft systems 
of either forced or induced draft design. 

Exception: Incinerators. 

10.3.4.3 Forced draft systems and all portions of induced 
draft systems under positive pressure during operation shall 
be designed and installed so as to prevent leakage of flue or 
vent gases into a building. 

10.3.4.4 Vent connectors serving equipment vented by natu- 
ral draft shall not be connected into any portion of mechani- 
cal draft systems operating under positive pressure. 

10.3.4.5 Where a mechanical draft system is employed, provi- 
sion shall be made to prevent the flow of gas to the main burn- 
ers when the draft system is not performing so as to satisfy the 
operating requirements of the equipment for safe perfor- 
mance. 

10.3.4.6 The exit terminals of mechanical draft systems shall 
be not less than 7 ft (2.1 m) above grade where located adja- 
cent to public walkways and shall be located as specified in 
10.8.1 and 10.8.2. 

10.3.5* Ventilating Hoods and Exhaust Systems. 

10.3.5.1 Ventilating hoods and exhaust systems shall be per- 
mitted to be used to vent gas utilization equipment installed in 
commercial applications. 

10.3.5.2 Where automatically operated gas utilization equip- 
ment is vented through a ventilating hood or exhaust system 
equipped with a damper or with a power means of exhaust, 
provisions shall be made to allow the flow of gas to the main 
burners only when the damper is open to a position to prop- 
erly vent the equipment and when the power means of ex- 
haust is in operation. 



2002 Edition 



54-48 



NATIONAL FUEL GAS CODE 



ANSI Z223. 1-48 



10.3.6 Circulating Air Ducts and Furnace Plenums. No por- 
tion of a venting system shall extend into or pass through any 
circulating air duct or furnace plenum. 

10.4 Type of Venting System to Be Used. 

10.4.1 The type of venting system to be used shall be in accor- 
dance with Table 10.4.1. 



Table 10.4.1 Type of Venting System to Be Used 

Gas Utilization Equipment Type of Venting System 

Listed Category I equipment Type B gas vent (10.6) 
Listed equipment equipped Chimney (10.5) 

with draft hood Single-wall metal pipe (10.7) 

Equipment listed for use with Listed chimney lining system 
Type B gas vent for gas venting (10.5.1.3) 

Special gas vent listed for this 
equipment (10.4.3) 



Listed vented wall furnaces 



Type B-W gas vent (10.6, 
9.27) 



Category II equipment 
Category III equipment 
Category IV equipment 



As specified or furnished by 
manufacturers of listed 
equipment (10.4.2, 10.4.3) 



Incinerators, outdoors 



Single-wall metal pipe [10.7, 
10.7.3(3)] 



Incinerators, indoors 
Equipment that can be 

converted to use of solid 

fuel 
Unlisted combination gas- 

and oil-burning equipment 
Combination gas- and 

solid-fuel-burning 

equipment 
Equipment listed for use with 

chimneys only 
Unlisted equipment 



Chimney (10.5) 



Listed combination gas- and 
oil-burning equipment 


Type Event (10.6) or 
chimney (10.5) 


Decorative appliance in 
vented fireplace 


Chimney (9.6.2.3) 


Gas-fired toilets 


Single-wall metal pipe (10.7, 
9.25.3) 


Direct-vent equipment 


See 10.2.5 


Equipment with integral vent 


See 10.2.6 



10.4.2 Plastic Piping. Plastic piping used for venting equip- 
ment listed for use with such venting materials shall be ap- 
proved. 

10.4.3 Special Gas Vent. Special gas vent shall be listed and 
installed in accordance with the terms of the special gas vent 
listing and the manufacturers' instructions. 



10.5 Masonry, Metal, and Factory-Built Chimneys. 

10.5.1 Listing or Construction. 

10.5.1.1 Factory-built chimneys shall be installed in accor- 
dance with their listing and the manufacturers' instructions. 
Factory-built chimneys used to vent appliances that operate at 
positive vent pressure shall be listed for such apphcation. 

10.5.1.2 Metal chimneys shall be built and installed in accor- 
dance with NEPA 211, Standard for Chimneys, Fireplaces, Vents, 
and Solid Fuel-Burning Appliances. 

10.5.1.3* Masonry chimneys shall be built and installed in ac- 
cordance with NFPA211, Standard for Chimneys, Fireplaces, Vents, 
and Solid Fuel-Burning Appliances, and lined with approved clay 
flue lining, a listed chimney lining system, or other approved 
material that will resist corrosion, erosion, softening, or crack- 
ing from vent gases at temperatures up to ISOO^F (982°C). 

Exception: Masonry chimney flues lined with a chimney lining sys- 
tem specifically listed for use with listed gas appliances with draft 
hoods. Category I appliances, and other gas appliances listed for use 
with Type B vents shall be permitted. The liner shall be installed in 
accordance with the liner manufacturer's instructions and the terms of 
the listing. A permanent identifying label shall be attached at the point 
where the connection is to be made to the liner. The label shall read 
"This chimney liner is for appliances that bum gas only. Do not con- 
nect to solid or liquid fuel-burning appliances or incinerators. " 

10.5.2 Termination. 

10.5.2.1 Achimney for residential-type or low-heat gas utiliza- 
tion equipment shall extend at least 3 ft (0.9 m) above the 
highest point where it passes through a roof of a building and 
at least 2 ft (0.6 m) higher than any portion of a building 
within a horizontal distance of 10 ft (3 m). (See Figure 10.5.2.1.) 

10.5.2.2 Achimneyfor medium-heat equipment shall extend 
at least 10 ft (3 m) higher than any pordon of any building 
within 25 ft (7.6 m). 

10.5.2.3 Achimney shall extend at least 5 ft (1.5 m) above the 
highest connected equipment draft hood outlet or flue collar. 

10.5.2.4 Decorative shrouds shall not be installed at the ter- 
mination of factory-built chimneys except where such shrouds 
are listed and labeled for use with the specific factory-built 
chimney system and are installed in accordance with manufac- 
turers' installation instructions. 

10.5.3 Size of Chimneys. 

10.5.3.1 The effective area of a chimney vendng system serv- 
ing listed gas appliances with draft hoods. Category I appli- 
ances, and other appliances listed for use with Type B vents 
shall be in accordance with one of the following methods: 



(1) 
(2) 



(3) 



Those listed in Chapter 13 

For sizing an individual chimney venting system for a 
single appliance with a draft hood, the effective areas of 
the vent connector and chimney flue shall be not less than 
the area of the appliance flue collar or draft hood outlet 
or greater than seven times the draft hood oudet area. 
For sizing a chimney venting system connected to two ap- 
pliances with draft hoods, the effective area of the chim- 
ney flue shall be not less than the area of the larger draft 
hood outlet plus 50 percent of the area of the smaller 
draft hood outlet, or greater than seven times the smaller 
draft hood outlet area. 



2002 Edition 



ANSI Z223.1-49 



VENTING OF EQUIPMENT 



54-49 



2 ft (0.6 m) 
minimum - 



■10 ft (3 m) 
or less 




10 ft (3 m) 
or less 



3 ft (0.9 m) 
minimum 

1 



Ciiimney J^if^ 



Chimney 
(a) Termination 10 ft (3 m) or less from ridge, wall, or parapet 




3 ft (0.9 m) 
minimum 



Chimney 



More than 
10 ft (3 m) 




Wall or 
parapet 



Note: No height 
above parapet 
required when 
distance from walls 
or parapet is more 



3 ft (0.9 m) 
minimum 



Chimney 



■Jiij^sl^ than 10 ft (3 m). 




Height above 
any roof surface 
within 10 ft (3 m) 
horizontally 



3 ft (0.9 m) 
minimum 



Chimney 




(b) Termination more than 10 ft (3 m) from ridge, wall, or parapet 



FIGURE 10.5.2.1 Typical Termination Locations for Chimneys and Single-Wall Metal Pipes 
Serving Residential-Type and Low-Heat Equipment. 



(4) Chimney venting systems using mechanical draft shall be 
sized in accordance with approved engineering methods. 

(5) Other approved engineering methods 

10.5.3.2 Where an incinerator is vented by a chimney serving 
other gas utilization equipment, the gas input to the incinera- 
tor shall not be included in calculating chimney size, provided 
the chimney flue diameter is not less than 1 in. (25 mm) larger 
in equivalent diameter than the diameter of the incinerator 
flue outlet. 

10.5.4 Inspection of Chimneys. 

10.5.4.1 Before replacing an existing appliance or connect- 
ing a vent connector to a chimney, the chimney passageway 
shall be examined to ascertain that it is clear and free of ob- 
structions and shall be cleaned if previously used for venting 
solid or liquid fuel-burning appliances or fireplaces. 

10.5.4.2 Chimneys shall be lined in accordance wdth 
NFPA211, Standard for Chimneys, Fireplaces, Vents, and Solid Fuel- 
Burning Appliances. 

Exception: Existing chimneys shall be permitted to have their use 
continued when an appliance is replaced by an appliance of similar 
type, input rating, and efficiency. 

10.5.4.3 Cleanouts shall be examined to determine that they 
will remain tightly closed when not in use. 

10.5.4.4 When inspection reveals that an existing chimney is 
not safe for the intended application, it shall be repaired, re- 



built, lined, relined, or replaced mth a vent or chimney to 
conform to NFPA 211, Standard for Chimneys, Fireplaces, Vents, 
and Solid Fuel-Burning Appliances, and shall be suitable for the 
equipment to be attached. 

10.5.5 Chimney Serving Equipment Burning Other Fuels. 

10.5.5.1 Gas utilization equipment shall not be connected to 
a chimney flue serving a separate appliance designed to burn 
solid fuel. 

10.5.5.2 Where one chimney serves gas utilization equipment 
and equipment burning liquid fuel, the equipment shall be 
connected through separate openings or shall be connected 
through a single opening where joined by a suitable fitting 
located as close as practical to the chimney. Where two or 
more openings are provided into one chimney flue, they shall 
be at different levels. Where the gas utilization equipment is 
automatically controlled, it shall be equipped with a safety 
shutoflF device. 

10.5.5.3* A listed combination gas- and solid fuel-burning ap- 
pliance connected to a single chimney flue shall be equipped 
v^th a manual reset device to shut off gas to the main burner 
in the event of sustained backdraft or flue gas spillage. The 
chimney flue shall be sized to properly vent the appliance. 

10.5.5.4 A single chimney flue serving a listed combination 
gas- and oil-burning appliance shall be sized to properly vent 
the appliance. 



2002 Edition 



54-50 



NATIONAL FUEL GAS CODE 



ANSI Z223. 1-50 



10.5.6 Support of Chimneys. All portions of chimneys shall be 
supported for the design and weight of the materials em- 
ployed. Listed factory-built chimneys shall be supported and 
spaced in accordance with their listings and the manufactur- 
ers' instructions. 

10.5.7 Cleanouts. Where a chimney that formerly carried flue 
products from liquid or solid fuel-burning appliances is used 
with an appliance using fuel gas, an accessible cleanout shall 
be provided. The cleanout shall have a tight-fitting cover and 
be installed so its upper edge is at least 6 in. (150 mm) below 
the lower edge of the lowest chimney inlet opening. 

10.5.8 Space Surrounding Lining or Vent. 

10.5.8.1 The remaining space surrounding a chimney liner, 
gas vent, special gas vent, or plastic piping installed within a 
masonry, chimney shall not be used to vent another appliance. 

Exception: The insertion of another liner or vent within the chimney 
as provided in this code and the liner or vent manufacturer's 
instructions. 

10.5.8.2 The remaining space surrounding a chimney liner, 
gas vent, special gas vent, or plastic piping installed within a 
masonry, metal or factory-built chimney flue shall not be used 
to supply combustion air. 

Exception: Direct vent gas-fired appliances designed for installation 
in a solid fuel-burning fireplace where installed in accordance with the 
listing and the manufacturer's instruction. 

10.6 Gas Vents. See Section 3.3. 

10.6.1 Application. The installation of gas vents shall meet the 
following requirements: 

(1) Gas vents shall be installed in accordance with the terms 
of their listings and the manufacturers' instructions. 

(2) A Type B-W gas vent shall have a listed capacity not less 
than that of the listed vented wall furnace to which it is 
connected. 

(3) A gas vent passing through a roof shall extend through 
the entire roof flashing, roof jack, or roof thimble and be 
terminated with a listed termination cap. 

(4) Type B or Type L vents shall extend in a generally vertical 
direction with offsets not exceeding 45 degrees, except 
that a vent system having not more than one 60-degree 
offset shall be permitted. Any angle greater than 45 de- 
grees from the vertical is considered horizontal. The total 
horizontal distance of a vent plus the horizontal vent con- 
nector serving draft hood-equipped appliances shall not 
be greater than 75 percent of the vertical height of the 
vent. 

Exception: Systems designed and sized as provided in Chapter 13 or 
in accordance with other approved engineering methods. 

(5) Vents serving Category I fan-assisted appliances shall be 
installed in accordance with the appliance manufactur- 
er's instructions and Chapter 13 or other approved engi- 
neering methods. 

(6) Gas vents installed within masonry chimneys shall be in- 
stalled in accordance with the terms of their listing and 
the manufacturers' installation instructions. Gas vents in- 
stalled within masonry chimneys shall be identified with a 
permanent label installed at the point where the vent en- 
ters the chimney. The label shall contain the following 
language: "This gas vent is for appliances that burn gas. 



(2) 



(3) 



(5) 



(b) 



Do not connect to solid or liquid fuel-burning appliances 
or incinerators." 

10.6.2 Gas Vent Termination. The termination of gas vents 
shall comply with the following requirements: 

(1) A gas vent shall terminate in accordance with one of the 
following: 

(a) Above the roof surface with a listed cap or listed roof 
assembly. Gas vents 12 in. (300 mm) in size or smaller 
with listed caps shall be permitted to be terminated in 
accordance with Figure 10.6.2 and Table 10.6.2, pro- 
vided they are at least 8 ft (2.4 m) from a vertical wall 
or similar obstruction. All other gas vents shall termi- 
nate not less than 2 ft (0.6 m) above the highest point 
where they pass through the roof and at least 2 ft 
(0.6 m) higher than any portion of a building 
within 10 ft (3 m). 

Industrial gas utilization equipment as provided in 
10.2.4. 

(c) Direct-vent systems as provided in 10.2.5. 

(d) Equipment with integral vents as provided in 10.2.6. 

(e) Mechanical draft systems as provided in 10.3.4. 

(f) Ventilating hoods and exhaust systems as provided in 
10.3.5. 

A Type B or a Type L gas vent shall terminate at least 5 ft 
(1.5 m) in vertical height above the highest connected 
equipment draft hood or flue collar. 
AType B-W gas vent shall terminate at least 12 ft (3.7 m) in 
vertical height above the bottom of the wall furnace. 
(4) A gas vent extending through an exterior wall shall not 
terminate adjacent to the wall or below eaves or parapets, 
except as provided in 10.2.5 and 10.3.4. 
Decorative shrouds shall not be installed at the termina- 
tion of gas vents except where such shrouds are listed for 
use with the specific gas venting system and are installed in 
accordance with manufacturers' installation instructions. 



Lowest discharge opening 
Listed - H" 1 \ 



cap 

Listed 
gas vent 




Roof pitch is x/12 



/-/(minimum) - 
Minimum height from roof 
to lowest discharge opening 



FIGURE 10.6.2 Gas Vent Termination Locations for Listed 
Caps 12 in. (300 mm) or Less in Size at Least 8 ft (2.4 m) from 
a Vertical Wall. 

10.6.3 Size of Gas Vents. Venting systems shall be sized and 
constructed in accordance with Chapter 13 or other approved 
engineering methods and the gas vent and gas equipment 
manufacturers' instructions. 

10.6.3.1* Category I Appliances. The sizing of natural draft 
venting systems serving one or more listed appliances equipped 



2002 Edition 



ANSI Z223. 1-51 



VENTING OF EQUIPMENT 



54-51 



Table 10.6.2 Roof Pitch Heights 



IW 



//(minimum) 



Gas furnace 



Roof Pitch 


ft 


m 


Flat to 6/12 


1.0 


0.30 


6/12 to 7/12 


1.25 


0.38 


Over 7/12 to 8/12 


1.5 


0.46 


Over 8/12 to 9/12 


2.0 


0.61 


Over 9/12 to 10/12 


2.5 


0.76 


Over 10/12 to 11/12 


3.25 


0.99 


Over 11/12 to 12/12 


4.0 


1.22 


Over 12/12 to 14/12 


5.0 


1.52 


Over 14/12 to 16/12 


6.0 


1.83 


Over 16/12 to 18/12 


7.0 


2.13 


Over 18/12 to 20/12 


7.5 


2.27 


Over 20/12 to 21/12 


8.0 


2.44 



with a draft hood or appliances listed for use with Type B gas vent, 
installed in a single story of a building, shall be in accordance 
with one of the following methods: 

(1) The provisions of Chapter 13. 

(2) Vents serving fan-assisted combustion system appliances, 
or combinations of fan-assisted combustion system and 
draft hood-equipped appliances shall be sized in accor- 
dance with Chapter 13 or other approved engineering 
methods. 

(3) For sizing an individual gas vent for a single, draft hood- 
equipped appliance, the effective area of the vent connec- 
tor and the gas vent shall be not less than the area of the 
appliance draft hood outlet or greater than seven times 
the draft hood oudet area. 

(4) For sizing a gas vent connected to two appliances, with 
draft hoods, the effective area of the vent shall be not less 
than the area of the larger draft hood outlet plus 50 per- 
cent of the area of the smaller draft hood outlet or greater 
than seven times the smaller draft hood outlet area. 

(5) Other approved engineering practices. 

10.6.3.2 Category IT, Category III, and Category IV Appli- 
ances. The sizing of gas vents for Category II, Category III, and 
Category IV gas utilization equipment shall be in accordance 
with the equipment manufacturers' instructions. 

10.6.3.3 Sizing. Chimney venting systems using mechanical 
draft shall be sized in accordance with approved engineering 
methods. 

10.6.4 Gas Vents Serving Equipment on More than One Floor. 

10.6.4.1 A single or common gas vent shall be permitted in 
multistory installations to vent Category I gas utilization equip- 
ment located on more than one floor level, provided the vent- 
ing system is designed and installed in accordance with ap- 
proved engineering methods. 

10.6.4.2 All gas utilization equipment connected to the com- 
mon vent shall be located in rooms separated from habitable 
space. Each of these rooms shall have provisions for an ad- 
equate supply of combustion, ventilation, and dilution air that 
is not supplied from habitable space. (See Figure 10.6.4.2.) 

10.6.4.3 The size of the connectors and common segments of 
multistory venting systems for gas utilization equipment listed 




Type B gas vents 



Air grilles in 
outside walls 



Louvered door could 
be used in lieu of 
outside wall grilles 



^¥' 



FIGURE 10.6.4.2 Plan View of Practical Separation Method 
for Multistory Gas Venting. 



for use with Type B double-wall gas vent shall be in accordance 
with Table 13.6, provided: 

(1) The available total height (H) for each segment of a mul- 
tistory venting system is the vertical distance between the 
level of the highest draft hood outlet or flue collar on that 
floor and the centerline of the next highest interconnec- 
tion tee. (See Figure G.l(k).) 

(2) The size of the connector for a segment is determined 
from its gas utilization equipment heat input and avail- 
able connector rise and shall not be smaller than the draft 
hood outlet or flue collar size. 

(3) The size of the common vertical vent segment, and of the 
interconnection tee at the base of that segment, shall be 
based on the total gas utilization equipment heat input 
entering that segment and its available total height. 

10.6.5 Support of Gas Vents. Gas vents shall be supported and 
spaced in accordance with their listings and the manufactur- 
ers' instructions. 

10.6.6 Marking. In those localities where solid and liquid fuels 
are used extensively, gas vents shall be permanentiy identified 
by a label attached to the wall or ceiling at a point where the 
vent connector enters the gas vent. The label shall read: "This 
gas vent is for appliances that burn gas. Do not connect to 
solid or liquid fuel-burning appliances or incinerators." The 
authority having jurisdiction shall determine whether its area 
constitutes such a locality. 

10.7 Single-WaU Metal Pipe. 

10.7.1 Construction. Single-wall metal pipe shall be con- 
structed of galvanized sheet steel not less than 0.0304 in. 
(0.7 mm) thick or of other approved, noncombustible, 
corrosion-resistant material. 

10.7.2 Cold Climate. Uninsulated single-wall metal pipe shall 
not be used outdoors in cold climates for venting gas utiliza- 
tion equipment. 

10.7.3 Termination. The termination of single-wall metal pipe 
shall meet the following requirements: 



2002 Edition 



54-52 



NATIONAL FUEL GAS CODE 



ANSI Z223. 1-52 



(1) Single-wall metal pipe shall terminate at least 5 ft (L5 m) 
in vertical height above the highest connected equipment 
draft hood outlet or flue collar. 

(2) Single-wall metal pipe shall extend at least 2 ft (0.6 m) 
above the highest point where it passes througharoof of a 
building and at least 2 ft (0.6 m) higher than any portion 
of a building within a horizontal distance of 10 ft (3 m). 
(See Figure 10.3.2.1.) 

(3) An approved cap or roof assembly shall be attached to the 
terminus of a single-wall metal pipe. (Also see 10. 7.4.3.) 

10.7.4 InstaUation with Equipment Permitted by 10.4.1. 

10.7.4.1 Single-wall metal pipe shall be used only for runs 
directly from the space in which the gas utilization equipment 
is located through the roof or exterior wall to the outer air. A 
pipe passing through a roof shall extend without interruption 
through the roof flashing, roof jacket, or roof thimble. 

10.7.4.2 Single-wall metal pipe shall not originate in any un- 
occupied attic or concealed space and shall not pass through 
any attic, inside wall, concealed space, or floor. (For the installa- 
tion of a single-wall metal pipe through an exterior combustible wall, 
see 10.10.14.2.) 

10.7.4.3 Single-wall metal pipe used for venting an incinera- 
tor shall be exposed and readily examinable for its full length 
and shall have suitable clearances maintained. 

10.7.4.4 Minimum clearances from single-wall metal pipe to 
combustible material shall be in accordance with Table 
10.7.4.4. Reduced clearances from single-wall metal pipe to 
combustible material shall be as specified for vent connectors 
in Table 9.2.3(b). 



10.7.4.5 Where a single-wall metal pipe passes through a roof 
constructed of combustible material, a noncombustible, non- 
ventilating thimble shall be used at the point of passage. The 
thimble shall extend at least 18 in. (460 mm) above and 6 in. 
(150 mm) below the roof with the annular space open at the 
bottom and closed only at the top. The thimble shall be sized 
in accordance with 10.10.14.2. 

10.7.5 Size of Single-Wall Metal Pipe. Single-wall metal piping 
shall comply with the following requirements: 

(1)*A venting system of a single-wall metal pipe shall be sized 
in accordance with one of the follovwng methods and the 
gas equipment manufacturer's instructions: 

(a) For a draft hood-equipped appliance, in accordance 
with Chapter 13 

(b) For a venting system for a single appliance with a 
draft hood, the areas of the connector and the pipe 
each shall not be less than the area of the appliance 
flue collar or draft hood outlet, whichever is smaller. 
The vent area shall not be greater than seven times 
the draft hood outlet area. 

(c) Other approved engineering methods 

(2) Where a single-wall metal pipe is used and has a shape 
other than round, it shall have an equivalent effective 
area equal to the effective area of the round pipe for 
which it is substituted and the minimum internal dimen- 
sion of the pipe shall be 2 in. (50 mm). 

(3) The vent cap or a roof assembly shall have a venting ca- 
pacity not less than that of the pipe to which it is attached. 



Table 10.7.4.4 Clearances for Connectors 



Minimum Distance from Combustible Material 



Equipment 



listed Type B 
Gas Vent Material 



Listed Type L 
Vent Material 



Single-Wall 
Metal Pipe 



Factory-Built 
Chimney Sections 



Listed equipment v«th 

draft hoods and 

equipment listed for 

use with Type B gas 

vents 
Residential boilers and 

furnaces with listed gas 

conversion burner and 

with draft hood 
Residential appliances 

listed for use with Type 
, L vents 

Listed gas-fired toilets 
Unlisted residential 

appliances with draft 

hood 
Residential and low-heat 

equipment other than 

those above 
Medium-heat equipment 



As listed 



6 in. 



Not permitted 



Not permitted 
Not permitted 



Not permitted 
Not permitted 



As listed 



6 in. 



As listed 



As listed 
6 in. 



9 in. 



Not permitted 



6 in. 



9 in. 



9 in. 



As listed 
9 in. 



18 in. 



36 in. 



As listed 



As listed 



As listed 



As listed 
As listed 



As listed 



As listed 



For SI units, 1 in. = 25.4 mm. 

Note: These clearances shall apply unless the listing of an appliance or connector specifies different 

clearances, in which case the listed clearances shall apply. 



2002 Edition 



ANSI Z223. 1-53 



VENTING OF EQUIPMENT 



54-53 



10.7.6 Support of Single-Wall Metal Pipe. All portions of 
single-wall metal pipe shall be supported for the design and 
weight of the material employed. 

10.7.7 Marking. Single-wall metal pipe shall comply with the 
marking provisions of 10.6.6. 

10.8* Through the Wall Vent Termination. 

10.8.1 A mechanical draft venting system shall terminate at 
least 3 ft (0.9 m) above any forced air inlet located within 10 ft 
(3 m). 

Exception No. 1: This provision shall not apply to the combustion air 
intake of a direct-vent appliance. 

Exception No. 2: This provision shall not apply to the separation of 
the integral outdoor air inlet and flue gas discharge of listed outdoor 
appliances. 

10.8.2 A mechanical draft venting system of other than 
direct-vent type shall terminate at least 4 ft (1.2 m) below, 4 ft 
(1.2 m) horizontally from, or 1 ft (300 mm) above any door, 
operable window, or gravity air inlet into any building. The 
bottom of the vent terminal shall be located at least 12 in. 
(300 mm) above grade. 

10.8.3 The vent terminal of a direct-vent appliance with an 
input of 10,000 Btu/hr (3 kW) or less shall be located at least 
6 in. (150 mm) from any air opening into a building, and such 
an appliance with an input over 10,000 Btu/hr (3 kW) but not 
over 50,000 Btu/hr (14.7 kW) shall be installed with a 9 in. 
(230 mm) vent termination clearance, and an appliance with 
an input over 50,000 Btu/hr (14.7 kW) shall have at least a 
12 in. (300 mm) vent termination clearance. The bottom of 
the vent terminal and the air intake shall be located at least 
12 in. (300 mm) above grade. 

10.8.4 Through-the-wall vents for Category II and Category 
IV appliances and noncategorized condensing appliances 
shall not terminate over public walkways or over an area where 
condensate or vapor could create a nuisance or hazard or 
could be detrimental to the operation of regulators, relief 
valves, or other equipment. Where local experience indicates 
that condensate is a problem with Category I and Category III 
appliances, this provision shall also apply. 

10.9 Condensation Drain. 

10.9.1 Provision shall be made to collect and dispose of con- 
densate from venting systems serving Category II and Cat- 
egory rV gas utilization equipment and noncategorized con- 
densing appliances in accordance with 10.8.4. 

10.9.2 Where local experience indicates that condensation is 
a problem, provision shall be made to drain off and dispose of 
condensate from venting systems serving Category I and Cat- 
egory III gas utilization equipment in accordance with 10.8.4. 

10.10 Vent Connectors for Category I Gas Utilization 
Equipment. 

10.10.1 Where Required. A vent connector shall be used to 
connect gas utilization equipment to a gas vent, chimney, or 
single-wall metal pipe, except where the gas vent, chimney, or 
single-wall metal pipe is directly connected to the equipment. 

10.10.2 Materials. 

10.10.2.1 Avent connector shall be made of noncombustible, 
corrosion-resistant material capable of withstanding the vent 



gas temperature produced by the gas utilization equipment 
and of sufficient thickness to withstand physical damage. 

10.10.2.2 Where the vent connector used for gas utilization 
equipment having a draft hood or a Category I appliance is 
located in or passes through an unconditioned area, that por- 
tion of the vent connector shall be listed Type B, Type L, or 
listed vent material having equivalent insulation qualities. 

Exception: Single-wall metal pipe located within the exterior walls of 
the building and located in areas having a local 99 percent winter 
design temperature of 5 °F or higher (see Figure G. 2. 4). 

10.10.2.3 Where the vent connector used for gas utilization 
equipment having a draft hood or a Category I appliance is 
located in or passes through attics and crawl spaces, that por- 
tion of the vent connector shall be listed Type B, Type L, or 
listed vent material having equivalent insulation qualities. 

10.10.2.4 Vent connectors for residential-type appliances 
shall comply with the following: 

(1) Vent Connectors not Installed in Attics, Crawl Spaces, or 
Other Unconditioned Areas. Vent connectors for listed 
gas appliances having draft hoods and for appliances hav- 
ing draft hoods and equipped with listed conversion 
burners that are not installed in attics, crawl spaces, or 
other unconditioned areas shall be one of the following: 

(a) Type B or Type L vent material 

(b) Galvanized sheet steel not less than 0.018 in. 
(0.46 mm) thick 

(c) Aluminum (1100 or 3003 alloy or equivalent) sheet 
not less than 0.027 in. (0.69 mm) thick 

(d) Stainless steel sheet not less than 0.012 in. (0.31 mm) 
thick 

(e) Smooth interior wall metal pipe having resistance to 
heat and corrosion equal to or greater than that of 
(b), (c), or (d) above 

(f) A listed vent connector 

(2) Vent connectors shall not be covered with insulation. 

Exception: Listed insulated vent connectors shall be installed accord- 
ing to the terms of their listing. 

10.10.2.5 Avent connector for low-heat equipment shall be a 
factory-built chimney section or steel pipe having resistance to 
heat and corrosion equivalent to that for the appropriate gal- 
vanized pipe as specified in Table 10.10.2.5. Factory-built 
chimney sections shall be joined together in accordance with 
the chimney manufacturer's instructions. 

10.10.2.6 Vent connectors for medium-heat equipment and 
commercial and industrial incinerators shall be constructed of 



Table 10.10.2.5 Minimum Thickness for Galvanized Steel 
Vent Connectors for Low-Heat Appliances 



Diameter of Connector 


Minimum Thickness 


(in.) 


(in.) 


Less than 6 


0.019 


6 to less than 10 


0.023 


10 to 12 inclusive 


0.029 


14 to 16 inclusive 


0.034 


Over 16 


0.056 



For SI units, 1 in. = 25.4 mm, 1 in.^ = 645 mm^ 



2002 Edition 



54-54 



NATIONAL FUEL GAS CODE 



ANSI Z223. 1-54 



factory-built, medium-heat chimney sections or steel of a 
thickness not less than that specified in Table 10.10.2.6 and 
shall comply with the following: 

( 1 ) A steel vent connector for equipment with a vent gas tem- 
perature in excess of 1000°F (538°C) measured at the en- 
trance to the connector shall be lined with medium-duty 
fire brick or the equivalent. 

(2) The lining shall be at least 2^2 in. (64 mm) thick for a vent 
connector having a diameter or greatest cross-sectional 
dimension of 18 in. (460 mm) or less. 

(3) The lining shall be at least 4^2 in. (110 mm) thick laid on 
the 4V2 in. (110 mm) bed for a vent connector having a 
diameter or greatest cross-sectional dimension greater 
than 18 in. (460 mm). 

(4) Factory-built chimney sections, if employed, shall be 
joined together in accordance with the chimney manufac- 
turer's instructions. 

Table 10.10.2.6 Minimum Thickness for Steel Vent 
Connectors for Medium-Heat Equipment and Commercial 
and Industrial Incinerators 

Vent Connector Size 



Diameter 


Area 


Mmuniun 
Thickness 


(in.) 


(in.^) 


(in.) 


Up to 14 


Up to 154 


0.053 


Over 14 to 16 


154 to 201 


0.067 


Over 16 to 18 


201 to 254 


0.093 


Over 18 


Larger than 254 


0.123 



For SI units, 1 in. = 25.4 mm, 1 in. = 645 mm^. 

10.10.3* Size of Vent Connector. 

10.10.3.1 Avent connector for gas utilization equipment with 
a single draft hood or for a Category I fan-assisted combustion 
system appliance shall be sized and installed in accordance 
with Chapter 13 or other approved engineering methods. 

10.10.3.2 For a single appliance having more than one draft 
hood outlet or flue collar, the manifold shall be constructed 
according to the instructions of the appliance manufacturer. 
Where there are no instructions, the manifold shall be de- 
signed and constructed in accordance with approved engi- 
neering practices. As an alternate method, the effective area of 
the manifold shall equal the combined area of the flue collars 
or draft hood outlets and the vent connectors shall have a 
minimum 1 ft (0.3 m) rise. 

10.10.3.3 Where two or more gas appliances are connected 
to a common vent or chimney, each vent connector shall be 
sized in accordance with Chapter 1 3 or other approved engi- 
neering methods. 

10.10.3.4 As an alternative method applicable only where all 
of the appliances are draft hood-equipped, each vent connec- 
tor shall have an effective area not less than the area of the 
draft hood outiet of the appliance to which it is connected. 

10.10.3.5 Where two or more gas appliances are vented 
through a common vent connector or vent manifold, the com- 
mon vent connector or vent manifold shall be located at the 
highest level consistent with available headroom and clear- 



ance to combustible material and shall be sized in accordance 
with Chapter 13 or other approved engineering methods. 

10.10.3.6 As an alternate method applicable only where 
there are two draft hood-equipped appliances, the effective 
area of the common vent connector or vent manifold and all 
junction fittings shall be not less than the area of the larger 
vent connector plus 50 percent of the area of the smaller flue 
collar outlet. 

10.10.3.7 Where the size of a vent connector is increased to 
overcome installation limitations and obtain connector capac- 
ity equal to the equipment input, the size increase shall be 
made at the equipment draft hood outiet. 

10.10.4 Two or More Appliances Connected to a Single Vent. 

10.10.4.1 Where two or more vent connectors enter a com- 
mon gas vent, chimney flue, or single-wall metal pipe, the 
smaller connector shall enter at the highest level consistent 
with the available headroom or clearance to combustible ma- 
terial. 

10.10.4.2 Vent connectors serving Category 1 appliances shall 
not be connected to any portion of a mechanical draft system 
operating under positive static pressure, such as those serving 
Category 111 or Category IV appliances. 

10.10.5 Clearance. Minimum clearances from vent connec- 
tors to combustible material shall be in accordance wdth Table 
10.7.4.4. 

Exception: The clearance between a vent connector and combustible 
material shall be permitted to be reduced where the combustible material 
is protected as specified for vent connectors in Table 9.2.3(2). 

10.10.6 Avoid Unnecessary Bends. Avent connector shall be 
installed so as to avoid turns or other construction features 
that create excessive resistance to flow of vent gases. 

10.10.7 Joints. Joints between sections of connector piping 
and connections to flue collars or draft hood outlets shall be 
fastened in accordance with one of the following methods: 

( 1 ) By sheet metal screws. 

(2) Vent connectors of listed vent material shall be assembled 
and connected to flue collars or draft hood outlets in ac- 
cordance with the manufacturers' instructions. 

(3) Other approved means. 

10.10.8 Slope. Avent connector shall be installed without any 
dips or sags and shall slope upward toward the vent or chim- 
ney at least Vi in. /ft (20 mm/m). 

Exception: Vent connectors attached to a mechanical draft system 
installed in accordance with the manufacturer's instructions. 

10.10.9 Length of Vent Connector. 

10.10.9.1 Avent connector shall be as short as practical and 
the gas utihzation equipment located as close as practical to 
the chimney or vent. 

10.10.9.2* Except as provided for in 10.10.3, the maximum 
horizontal length of a single-wall connector shall be 75 per- 
cent of the height of the chimney or vent. Except as provided 
for in 10.10.3, the maximum horizontal length of a Type B 
double-wall connector shall be 100 percent of the height of 
the chimney or vent. For a chimney or vent system serving 
multiple appliances, the maximum length of an individual 
connector, from the appliance outlet to the junction with the 
common vent or another connector, shall be 100 percent of 
the height of the chimney or vent. 



2002 Edition 



ANSI Z223. 1-55 



VENTING OF EQUIPMENT 



54-55 



10.10.10 Support. A vent connector shall be supported for 
the design and weight of the material employed to maintain 
clearances and prevent physical damage and separation of 
joints. 

10.10.11 Chimney Connection. Where entering a flue in a ma- 
sonry or metal chimney, the vent connector shall be installed 
above the extreme bottom to avoid stoppage. Where thimble 
or slip joint is used to facilitate removal of the connector, the 
connector shall be firmly attached to or inserted into the 
thimble or slip joint to prevent the connector from falling out. 
Means shall be employed to prevent the connector from en- 
tering so far as to restrict the space between its end and the 
opposite wall of the chimney flue. 

10.10.12 Inspection. The entire length of a vent connector 
shall be readily accessible for inspection, cleaning, and re- 
placement. 

10.10.13 Fireplaces. A vent connector shall not be connected 
to a chimney flue serving a fireplace unless the fireplace flue 
opening is permanently sealed. 

10.10.14 Passage Through Ceilings, Floors, or Walls. 

10.10.14.1 A vent connector shall not pass through any ceil- 
ing, floor, or fire-resistance rated wall. A single-wall metal pipe 
connector shall not pass through any interior wall. 

Exception: Vent connectors made of listed Type B or Type L vent 
material and serving listed equipment with draft hoods and other 
equipment listed for use with Type B gas vents that pass through walls 
or partitions constructed of combustible material shall be installed with 
not less than the listed clearance to combustible material. 

10.10.14.2 A vent connector made of a single-wall metal pipe 
shall not pass through a combustible exterior wall unless 
guarded at the point of passage by a ventilated metal thimble 
not smaller than the following: 

(1) For listed appliances with draft hoods and appliances 
listed for use with Type B gas vents, the thimble shall be a 
minimum of 4 in. (100 mm) larger in diameter than the 
vent connector. Where there is a run of not less than 6 ft 
(1.8 m) of vent connector in the opening between the 
draft hood outlet and the thimble, the thimble shall be a 
minimum of 2 in. (50 mm) larger in diameter than the 
vent connector. 

(2) For unlisted appliances having draft hoods, the thimble 
shall be a minimum of 6 in. (150 mm) larger in diameter 
than the vent connector. 

(3) For residential and low-heat appliances, the thimble shall 
be a minimum of 12 in. (300 mm) larger in diameter than 
the vent connector. 

Exception: In lieu of thimble protection, all combustible material in 
the wall shall be removed from the vent connector a sufficient distance 
to provide the specified clearance from such vent connector to combus- 
tible material. Any material used to close up such opening shall be 
noncombustible. 

10.10.14.3 Vent connectors for medium-heat equipment 
shall not pass through walls or partitions constructed of com- 
bustible material. 

10.11 Vent Connectors for Category II, Category III, and 
Category IV Gas Utilization Equipment. See Section 10.4. 

10.12 Draft Hoods and Draft Controls. 

10.12.1 Equipment Requiring Draft Hoods. Vented gas utili- 
zation equipment shall be installed with draft hoods. 



Exception: Dual oven-type combination ranges, incinerators, direct-vent 
equipment, fan-assisted combustion system appliances, equipment requir- 
ing chimney draft for operation, single-firebox boilers equipped with con- 
version burners with inputs greater than 400, 000 Btu/hr (11 7 kW), 
equipment equipped with blast, power, or pressure burners that are not 
listed for use with draft hoods, and equipment designed for forced venting. 

10.12.2 Installation. A draft hood supplied with or forming a 
part of listed vented gas utilization equipment shall be in- 
stalled without alteration, exactly as furnished and specified 
by the equipment manufacturer. 

10.12.2.1 If a draft hood is not supplied by the equipment 
manufacturer where one is required, a draft hood shall be 
installed, be of a listed or approved type, and, in the absence 
of other instructions, be of the same size as the equipment flue 
collar. Where a draft hood is required with a conversion 
burner, it shall be of a listed or approved type. 

10.12.2.2 Where it is determined that a draft hood of special 
design is needed or preferable for a particular installation, the 
installation shall be in accordance with the recommendations 
of the equipment manufacturer and shall be with the approval 
of the authority having jurisdiction. 

10.12.3 Draft Control Devices. Where a draft control device 
is part of the gas utilization equipment or is supplied by the 
equipment manufacturer, it shall be installed in accordance 
with the manufacturer's instructions. In the absence of 
manufacturer's instructions, the device shall be attached to 
the flue collar of the equipment or as near to the equip- 
ment as practical. 

10.12.4* Additional Devices. Gas utilization equipment (ex- 
cept incinerators) requiring controlled chimney draft shall be 
permitted to be equipped with a listed double-acting baromet- 
ric draft regulator installed and adjusted in accordance with 
the manufacturers' instructions. 

10.12.5 Location. Draft hoods and barometric draft regula- 
tors shall be installed in the same room or enclosure as the 
equipment in such a manner as to prevent any difference in 
pressure between the hood or regulator and the combustion 
air supply. 

10.12.6 Positioning. Draft hoods and draft regulators shall be 
installed in the position for which they were designed with 
reference to the horizontal and vertical planes and shall be 
located so that the relief opening is not obstructed by any part 
of the equipment or adjacent construction. The equipment 
and its draft hood shall be located so that the relief opening is 
accessible for checking vent operation. 

10.12.7 Clearance. A draft hood shall be located so that its 
relief opening is not less than 6 in. (150 mm) from any surface 
except that of the equipment it serves and the venting system 
to which the draft hood is connected. Where a greater or 
lesser clearance is indicated on the equipment label, the clear- 
ance shall not be less than that specified on the label. Such 
clearances shall not be reduced. 

10.13 Manually Operated Dampers. A manually operated 
damper shall not be placed in any equipment vent connector. 
Fixed baffles shall not be classified as manually operated 
dampers. 

10.14 Automatically Operated Vent Dampers. An automati- 
cally operated vent damper shall be of a listed type. 



2002 Edition 



54-56 



NATIONAL FUEL GAS CODE 



ANSI Z223. 1-56 



10.15 Obstructions. Devices that retard the flow of vent gases 
shall not be installed in a vent connector, chimney, or vent. 
The following shall not be considered as obstructions: 

(1) Draft regulators and safety controls specifically listed for 
installation in venting systems and installed in accordance 
with the terms of their listing. 

(2) Approved draft regulators and safety controls designed 
and installed in accordance with approved engineering 
methods. 

(3) Listed heat reclaimers and automatically operated vent 
dampers installed in accordance with the terms of their 
listing. 

(4) Vent dampers serving listed appliances installed in accor- 
dance with 13.1.1 and 13.2.1 or other approved engineer- 
ing methods. 

(5) Approved economizers, heat reclaimers, and recupera- 
tors installed in venting systems of equipment not re- 
quired to be equipped with draft hoods, provided the gas 
utilization equipment manufacturer's instructions cover 
the installation of such a device in the venting system and 
performance in accordance with 10.3.1 and 10.3.2 is 
obtained. 



Chapter 11 Procedures to Be Followed to Place 
Equipment in Operation 

11.1 Adjusting the Burner Input. 

11.1.1* Adjusting Input. The input shall be adjusted to the 
proper rate in accordance with the equipment manufacturers' 
instructions by changing the size of a fixed orifice, changing 
the adjustment of an adjustable orifice, or readjusting the gas 
pressure regulator outlet pressure (where a regulator is pro- 
vided). Overfiring shall be prohibited. (See Table 11.1.1.) 



Table 11.1.1 Gas Input to Burner in Cubic Feet per Hour 



Table 11.1.1 Continued 



Seconds 

for One 

Revolution 



Size of Test Meter Dial 



>/2 f t^ 



Ift^ 



2 ft" 



5ft^ 



10 
11 
12 
13 
14 



180 
164 
150 
138 
129 



360 

327 
300 

277 
257 



15 
16 
17 
18 
19 



120 
112 
106 
100 
95 



240 
225 
212 
200 
189 



20 
21 
22 
23 
24 



90 
86 
82 
78 
75 



180 
171 
164 
157 
150 



720 


1800 


655 


1636 


600 


1500 


555 


1385 


514 


1286 


480 


1200 


450 


1125 


424 


1059 


400 


1000 


379 


947 


360 


900 


343 


857 


327 


818 


313 


783 


300 


750 



25 


72 


144 


288 


720 


26 


69 


138 


277 


692 


27 


67 


133 


267 


667 



Seconds 




Size of Test Meter Dial 




Revolution 


V2 f t^ 


Ift^ 


2 ft" 


5 ft" 


28 
29 


64 
62 


129 
124 


257 
248 


643 
621 



30 
31 
32 
33 
34 



35 
36 
37 
38 
39 



40 
41 
42 
43 
44 



45 
46 
47 
48 
49 



50 
51 
52 
53 
54 



55 
56 

57 
58 
59 



60 
62 
64 
66 

68 



70 
72 
74 
76 
78 



80 
82 
84 
86 



60 
58 
56 
55 
53 



51 
50 
49 
47 
46 



45 
44 
43 
42 
41 



40 
39 
38 
37 
37 



36 
35 
35 
34 
33 



33 
32 
32 
31 
30 



30 
29 
29 
29 

28 



26 
25 
24 
24 
23 



22 
22 
21 
21 
20 



120 
116 
113 
109 
106 



103 

100 

97 

95 

92 



90 

88 
86 
84 
82 



80 
78 

77 
75 
73 



72 
71 
69 
68 
67 



65 
64 
63 
62 
61 



60 
58 
56 
54 
53 



51 
50 
48 
47 
46 



45 
44 
43 
42 
41 



240 
232 
225 
218 
212 



206 
200 
195 
189 

185 



180 
176 
172 
167 
164 



160 
157 
153 
150 
147 



144 
141 
138 
136 
133 



131 
129 
126 
124 
122 



120 
116 
112 
109 
106 



103 

100 

97 

95 

92 



90 

88 
86 
84 
82 



600 
581 
563 
545 
529 



514 
500 

486 
474 
462 



450 
440 
430 
420 
410 



400 
391 
383 
375 
367 



360 
353 
346 
340 
333 



327 
321 
316 
310 
305 



300 
290 
281 
273 
265 



257 
250 
243 
237 
231 



225 
220 
214 
209 
205 



90 


20 


40 


80 


200 


94 


19 


38 


76 


192 



2002 Edition 



ANSI Z223. 1-57 



PIPE SIZING 



54-57 



Table 11.1.1 Continued 



Seconds 




Size of Test Meter Dial 




e r\ 




















Revolution 


1/2 f t^ 


Ift^ 


2ft^ 


5ft^ 


98 


18 


37 


74 


184 


100 


18 


36 


72 


180 


104 


17 


35 


69 


173 


108 


17 


33 


67 


167 


112 


16 


32 


64 


161 


116 


15 


31 


62 


155 


120 


15 


30 


60 


150 


130 


14 


28 


55 


138 


140 


13 


26 


51 


129 


150 


12 


24 


48 


120 


160 


11 


22 


45 


112 


170 


11 


21 


42 


106 


180 


10 


20 


40 


100 



Note: To convert to Btu per hour, multiply by the Btu heating value of 
the gas used. 



11.1.2 High Altitude. Ratings of gas utilization equipment are 
based on sea level operation and shall not be changed for 
operation at elevations up to 2000 ft (600 m) . For operation at 
elevations above 2000 ft (600 m), equipment ratings shall be 
reduced in accordance wdth one of the following methods: 

(1) At the rate of 4 percent for each 1000 ft (300 m) above sea 
level before selecting appropriately sized equipment. 

(2) As permitted by the authority having jurisdiction. 

(3) Listed appliances derated in accordance with the terms of 
the listing shall be permitted. 

11.2* Primary Air Adjustment. The primary air for injection 
(Bunsen)-type burners shall be adjusted for proper flame 
characteristics in accordance with the manufacturers' instruc- 
tions. After setting the primary air, the adjustment means shall 
be secured in position. 

11.3 Safety Shutoff Devices. Where a safety shutoflf device is 
provided, it shall be checked for proper operation and adjust- 
ment in accordance with the manufacturer's instructions. 
Where the device does not function properly to turn off the 
gas supply in the event of pilot outage, it shall be properly 
serviced or replaced with new equipment. 

11.4 Automatic Ignition. Gas utilization equipment supplied 
vsith means for automatic ignition shall be checked for proper 
operation. If necessary, proper adjustments shall be made. 

11.5 Protective Devices. All protective devices furnished with 
the gas utilization equipment, such as a limit control, fan con- 
trol to blower, temperature and pressure relief valve, low-water 
cutoff device, or manual operating features, shall be checked 
for proper operation. 

11.6* Checking the Draft. Vent-connected gas utilization 
equipment shall be operated for several minutes and checked 
to see that the combustion products are going up the chimney 
or gas vent properly by passing a lighted match or taper 
around the edge of the relief opening of the draft hood. 
Where the chimney or gas vent is drawing properly, the match 
flame will be drawn into the draft hood. Where not, the com- 



bustion products will tend to extinguish this flame. Where the 
combustion products are escaping from the relief opening of 
the draft hood, the equipment shall not be operated until 
proper adjustments or repairs are made to provide adequate 
draft through the chimney or gas vent. 

11.7 Operating Instructions. Operating instructions shall be 
furnished and shall be left in a prominent position near the 
equipment for the use of the consumer. 

Chapter 12 Pipe Sizing 

12.1 Pipe Sizing Methods. Where the pipe size is to be deter- 
mined using any of the methods in 12.1.1 through 12.1.3, the 
diameter of each pipe segment shall be obtained from the 
pipe sizing tables in Section 12.2 or from the sizing equations 
in Section 12.3. (See calculation examples in Annex C.) For SI 
units, 1 ft^ - 0.028 m^, 1 ft = 0.305 m, 1 in. w.c. = 0.249 kPa, 1 psi 
= 6.894 kPa, 1000 Btu/hr = 0.293 kW. 

12.1.1* Longest Length Method. The pipe size of each section 
of gas piping shall be determined using the longest length of 
piping from the point of delivery to the most remote outlet 
and the load of the section. 

12.1.2* Branch Length Method. Pipe shall be sized as follows: 

(1) Pipe size of each section of the longest pipe run from the 
point of delivery to the most remote outlet shall be deter- 
mined using the longest run of piping and the load of the 
section. 

(2) The pipe size of each section of branch piping not previ- 
ously sized shall be determined using the length of piping 
from the point of delivery to the most remote outlet in 
each branch and the load of the section. 

12.1.3 Hybrid Pressure. The pipe size for each section of 
higher pressure gas piping shall be determined using the 
longest length of piping from the point of delivery to the most 
remote line pressure regulator. The pipe size from the line 
pressure regulator to each outlet shall be determined using 
the length of piping from the regulator to the most remote 
outlet served by the regulator. 

12.2 Tables for Sizing Gas Piping Systems. Table 12.1 
through Table 12.33 shall be used to size gas piping in con- 
junction with one of the methods described in 12.1.1 through 

12.1.3. 

12.3 Sizing Equations. The inside diameter of smooth wall 
pipe or tubing shall be determined by the sizing equations in 
12.3.1 and 12.3.2 using the equivalent pipe length determined 
by the methods in 12.1.1 through 12.1.3. 

12.3.1* Low Pressure Gas Formula [Less than 1.5 
(10.3 kPa)]: 



psi 



D = 



Q' 



19.17 



f AH 

[CrxL 



12.3.2* High Pressure Gas Formula [1.5 psi (10.3 kPa) and 
above]: 



D = 



18.93 



CrxL 



2002 Edition 



54-58 



NATIONAL FUEL GAS CODE 



ANSI Z223.1-58 



Table 12.1 Schedule 40 Metallic Pipe 








Gas 


Natural 




Inlet pressure 


0.50 psi or less 




Pressure Drop 


0.30 in. w.c. 




Specific Gravity 


0.60 



Pipe Size (in.) 



Nominal 


1/4 


3/8 


'/2 


3/4 


1 


l'/4 


114 


2 


21/2 


3 


4 


Actual ID 


0.364 


0.493 


0.622 


0.824 


1.049 


1.380 


1.610 


2.067 


2.469 


3.068 


4.026 


Length 

(ft) 


Maximum Capacity in Cubic Feet of Gas per Hour 


10 


32 


72 


132 


278 


520 


1,050 


1,600 


3,050 


4,800 


8,500 


17,500 


20 


22 


49 


92 


190 


350 


730 


1,100 


2,100 


3,300 


5,900 


12,000 


30 


18 


40 


73 


152 


285 


590 


890 


1,650 


2,700 


4,700 


9,700 


40 


15 


34 


63 


130 


245 


500 


760 


1,450 


2,300 


4,100 


8,300 


50 


14 


30 


56 


115 


215 


440 


670 


1,270 


2,000 


3,600 


7,400 


60 


12 


27 


50 


105 


195 


400 


610 


1,150 


1,850 


3,250 


6,800 


70 


11 


25 


46 


96 


180 


370 


560 


1,050 


1,700 


3,000 


6,200 


80 


11 


23 


43 


90 


170 


350 


530 


990 


1,600 


2,800 


5,800 


90 


10 


22 


40 


84 


160 


320 


490 


930 


1,500 


2,600 


5,400 


100 


9 


21 


38 


79 


150 


305 


460 


870 


1,400 


2,500 


5,100 


125 


8 


18 


34 


72 


130 


275 


410 


780 


1,250 


2,200 


4,500 


150 


8 


17 


31 


64 


120 


250 


380 


710 


1,130 


2,000 


4,100 


175 


7 


15 


28 


59 


110 


225 


350 


650 


1,050 


1,850 


3,800 


200 


6 


14 


26 


55 


100 


210 


320 


610 


980 


1,700 


3,500 



where: 

D = inside diameter of pipe, in. 

Q = input rate appliance (s), cubic feet per hour at 
60°F and 30 in. mercury column 
Pi = upstream pressure, psia (P^ + 14.7) 
P2 = downstream pressure, psia (Pg + 14.7) 

L = equivalent length of pipe, ft 
AH = pressure drop, in. w.c. (27.7 in. HgO = 1 psi) 

See Table 12.3.2 for values of Grand Y. 



Table 12.3.2 Crand Ffor Natural Gas and Undiluted 
Propane at Standard Conditions 



Formula Factors 



Gas 



Cr 



Natural Gas 

Undiluted 

Propane 



0.6094 
1.2462 



0.9992 
0.9910 



2002 Edition 



ANSI Z223.1-59 



PIPE SIZING 



54-59 



Table 12.2 Schedule 40 Metallic Pipe 








Gas 


Natural 




Inlet pressure 


0.50 psi or less 




Pressure Drop 


0.50 in. w.c. 




Specific Gravity 


0.60 



Pipe Size (in.) 



Nominal 


1/4 


% 


V2 


% 


1 


VA 


11/2 


2 


21/2 


3 


4 


Actual ID 


0.364 


0.493 


0.622 


0.824 


1.049 


1.380 


1.610 


2.067 


2.469 


3.068 


4.026 


Length 

(ft) 


Maximum Capacity in Cubic Feet of Gas per Hour 


10 


43 


95 


175 


360 


680 


1,400 


2,100 


3,950 


6,300 


11,000 


23,000 


20 


29 


65 


120 


250 


465 


950 


1,460 


2,750 


4,350 


7,700 


15,800 


30 


24 


52 


97 


200 


375 


770 


1,180 


2,200 


3,520 


6,250 


12,800 


40 


20 


45 


82 


170 


320 


660 


990 


1,900 


3,000 


5,300 


10,900 


50 


18 


40 


73 


151 


285 


580 


900 


1,680 


2,650 


4,750 


9,700 


60 


16 


36 


66 


138 


260 


530 


810 


1,520 


2,400 


4,300 


8,800 


70 


15 


33 


61 


125 


240 


490 


750 


1,400 


2,250 


3,900 


8,100 


80 


14 


31 


57 


118 


220 


460 


690 


1,300 


2,050 


3,700 


7,500 


90 


13 


29 


53 


110 


205 


430 


650 


1,220 


1,950 


3,450 


7,200 


100 


12 


27 


50 


103 


195 


400 


620 


1,150 


1,850 


3,250 


6,700 


125 


11 


24 


44 


93 


175 


360 


550 


1,020 


1,650 


2,950 


6,000 


150 


10 


22 


40 


84 


160 


325 


500 


950 


1,500 


2,650 


5,500 


175 


9 


20 


37 


77 


145 


300 


460 


850 


1,370 


2,450 


5,000 


200 


8 


19 


35 


72 


135 


280 


430 


800 


1,280 


2,280 


4,600 



2002 Edition 



54-60 



NATIONAL FUEL GAS CODE 



ANSI Z223. 1-60 



Table 12.3 Schedule 40 Metallic Pipe 








Gas 


Natural 




Inlet pressure 


2.0 psi 




Pressure Drop 


1.0 psi 




SpeciHc Gravity 


0.60 



Pipe Size (in.) 



Nominal 


1/2 


% 


1 


VA 


VA 


2 


2'/2 


3 


4 


Actual ID 


0.622 


0.824 


1.049 


1.380 


1.610 


2.067 


2.469 


3.068 


4.026 


Length 

(ft) 


Maximum Capacity in Cubic Feet of Gas per Hoiu- 


10 


1,506 


3,041 


5,561 


11,415 


17,106 


32,944 


52,505 


92,819 


189,326 


20 


1,065 


2,150 


3,932 


8,072 


12,096 


23,295 


37,127 


65,633 


133,873 


30 


869 


1,756 


3,211 


6,591 


9,876 


19,020 


30,314 


53,589 


109,307 


40 


753 


1,521 


2,781 


5,708 


8,553 


16,472 


26,253 


46,410 


94,663 


50 


673 


1,360 


2,487 


5,105 


7,650 


14,733 


23,481 


41,510 


84,669 


60 


615 


1,241 


2,270 


4,660 


6,983 


13,449 


21,435 


37,893 


77,292 


70 


569 


1,150 


2,102 


4,315 


6,465 


12,452 


19,845 


35,082 


71,558 


80 


532 


1,075 


1,966 


4,036 


6,048 


11,647 


18,563 


32,817 


66,937 


90 


502 


1,014 


1,854 


3,805 


5,702 


10,981 


17,502 


30,940 


63,109 


100 


462 


934 


1,708 


3,508 


5,257 


10,125 


16,138 


28,530 


58,194 


125 


414 


836 


1,528 


3,138 


4,702 


9,056 


14,434 


25,518 


52,050 


150 


372 


751 


1,373 


2,817 


4,222 


8,130 


12,960 


22,911 


46,732 


175 


344 


695 


1,271 


2,608 


3,909 


7,527 


11,999 


21,211 


43,265 


200 


318 


642 


1,174 


2,413 


3,613 


6,959 


11,093 


19,608 


39,997 



2002 Edition 



ANSI Z223. 1-61 



PIPE SIZING 



54-61 



Table 12.4 Schedule 40 Metallic Pipe 








Gas 


Natural 




Inlet pressure 


5.0 psi 




Pressure Drop 


3.5 psi 




Specific Gravity 


0.60 



Pipe Size (in.) 



Nominal 


'A 


3/4 


1 


l'/4 


l'/2 


2 


21/2 


3 


4 


Actual ID 


0.622 


0.824 


1.049 


1.380 


1.610 


2.067 


2.469 


3.068 


4.026 


Length 

(ft) 


Maximum Capacity in Cubic Feet of Gas per Hour 


10 


3,185 


6,434 


11,766 


24,161 


36,206 


69,727 


111,133 


196,468 


400,732 


20 


2,252 


4,550 


8,320 


17,084 


25,602 


49,305 


78,583 


138,924 


283,361 


30 


1,839 


3,715 


6,793 


13,949 


20,904 


40,257 


64,162 


113,431 


231,363 


40 


1,593 


3,217 


5,883 


12,080 


18,103 


34,864 


55,566 


98,234 


200,366 


50 


1,425 


2,878 


5,262 


10,805 


16,192 


31,183 


49,700 


87,863 


179,213 


60 


1,301 


2,627 


4,804 


9,864 


14,781 


28,466 


45,370 


80,208 


163,598 


70 


1,204 


2,432 


4,447 


9,132 


13,685 


26,354 


42,004 


74,258 


151,463 


80 


1,153 


2,330 


4,260 


8,542 


12,801 


24,652 


39,291 


69,462 


141,680 


90 


1,062 


2,145 


3,922 


8,054 


12,069 


23,242 


37,044 


65,489 


133,577 


100 


979 


1,978 


3,617 


7,427 


11,128 


21,433 


34,159 


60,387 


123,173 


125 


876 


1,769 


3,235 


6,643 


9,953 


19,170 


30,553 


54,012 


110,169 


150 


786 


1,589 


2,905 


5,964 


8,937 


17,211 


27,431 


48,494 


98,911 


175 


728 


1,471 


2,690 


5,522 


8,274 


15,934 


25,396 


44,897 


91,574 


200 


673 


1,360 


2,487 


5,104 


7,649 


14,729 


23,478 


41,504 


84,656 



2002 Edition 



54-62 



NATIONAL FUEL GAS CODE 



ANSI Z223. 1-62 



Table 12.5 Schedule 40 Metallic Pipe 








Gas 


Natural 




Inlet pressure 


LO psi or less 




Pressure Drop 


0.30 in. w.c. 




Specific Gravity 


0.60 



Pipe Size (in.) 



Nominal 


1 


VA 


VA 


2 


2'/2 


3 


3'/2 


4 


5 


6 


8 


10 


12 


Actual ID 


1.049 


1.380 


1.610 


2.067 


2.469 


3.068 


3.548 


4.026 


5.047 


6.065 


7.981 


10.020 


11.938 


Length 

(ft) 


Maximum Capacity in Cubic Feet of Gas per Hour 


50 


215 


442 


662 


1,275 


2,033 


3,594 


5,262 


7,330 


13,261 


21,472 


44,118 


80,130 


126,855 


100 


148 


304 


455 


877 


1,397 


2,470 


3,616 


5,038 


9,114 


14,758 


30,322 


55,073 


87,187 


150 


119 


244 


366 


704 


1,122 


1,983 


2,904 


4,046 


7,319 


11,851 


24,350 


44,225 


70,014 


200 


102 


209 


313 


602 


960 


1,698 


2,485 


3,462 


6,264 


10,143 


20,840 


37,851 


59.923 


250 


90 


185 


277 


534 


851 


1,505 


2,203 


3,069 


5,552 


8,990 


18,470 


33,547 


53,109 


300 


82 


168 


251 


484 


771 


1,363 


1,996 


2,780 


5,030 


8,145 


16,735 


30,396 


48,120 


400 


70 


143 


215 


414 


660 


1,167 


1,708 


2,380 


4,305 


6,971 


14,323 


26,015 


41,185 


500 


62 


127 


191 


367 


585 


1,034 


1,514 


2,109 


3,816 


6,178 


12,694 


23,056 


36,501 


1,000 


43 


87 


131 


252 


402 


711 


1,041 


1,450 


2,623 


4,246 


8,725 


15,847 


25,087 


1,500 


34 


70 


105 


203 


323 


571 


836 


1,164 


2,106 


3,410 


7,006 


12,725 


20,146 


2,000 


29 


60 


90 


173 


276 


488 


715 


996 


1,802 


2,919 


5,997 


10,891 


17,242 



Table 12.6 Schedule 40 MetaUic Pipe 








Gas 


Natural 




Inlet pressure 


1.0 psi or less 




Pressure Drop 


0.50 in. w.c. 




Specific Gravity 


0.60 



Pipe Size (in.) 



Nomina] 


1 


I 'A 


V/2 


2 


2'/2 


3 


31/2 


4 


5 


6 


8 


10 


12 


Actual ID 


1.049 


1.380 


1.610 


2.067 


2.469 


3.068 


3.548 


4.026 


5.047 


6.065 


7.981 


10.020 


11.938 


Length 

(ft) 










Msixim 


um Capacit 


y in Cubic F 


eet of Gas p 


er Hour 










50 


284 


583 


873 


1,681 


2,680 


4,738 


6,937 


9,663 


17,482 


28,308 


58,161 


105,636 


167,236 


100 


195 


400 


600 


1,156 


1,842 


3,256 


4,767 


6,641 


12,015 


19,456 


39,974 


72,603 


114,940 


150 


157 


322 


482 


928 


1,479 


2,615 


3,828 


5,333 


9,649 


15,624 


32,100 


58,303 


92,301 


200 


134 


275 


412 


794 


1,266 


2,238 


3,277 


4,565 


8,258 


13,372 


27,474 


49,900 


78,998 


250 


119 


244 


366 


704 


1,122 


1,983 


2,904 


4,046 


7,319 


11,851 


24,350 


44,225 


70,014 


300 


108 


221 


331 


638 


1,017 


1,797 


2,631 


3,666 


6,632 


10,738 


22,062 


40,071 


63,438 


400 


92 


189 


283 


546 


870 


1,538 


2,252 


3,137 


5,676 


9,190 


18,883 


34,296 


54,295 


500 


82 


168 


251 


484 


771 


1,363 


1,996 


2,780 


5,030 


8,145 


16,735 


30,396 


48,120 


1,000 


56 


115 


173 


333 


530 


937 


1,372 


1,911 


3,457 


5,598 


11,502 


20,891 


33,073 


1,500 


45 


93 


139 


267 


426 


752 


1,102 


1,535 


2,776 


4,496 


9,237 


16,776 


26,559 


2,000 


39 


79 


119 


229 


364 


644 


943 


1,313 


2,376 


3,848 


7,905 


14,358 


22,731 



2002 Edition 



ANSI Z223. 1-63 



PIPE SIZING 



54-63 



Table 12.7 Semi-Rigid Copper Tubing 








Gas 


Natural 




Inlet pressure 


0.5 psi or less 




Pressure Drop 


0.3 in. w.c. 




Specific Gravity 


0.60 



Tube Size (in.) 





K&L 


'/4 


Vs 


'/2 


5/8 


% 


1 


l'/4 


\¥z 


2 


2Vi 


Nominal 


ACR 


3/8 


¥i 


5/8 


-74 


% 


I'/s 


F/a 


1% 


2'/8 


25/8 


Outside 


0.375 


0.500 


0.625 


0.750 


0.875 


1.125 


1.375 


1.625 


2.125 


2.625 


Inside' 


0.305 


0.402 


0.527 


0.652 


0.745 


0.995 


1.245 


1.481 


1.959 


2.435 


Length 

(ft) 


Maximum Capacity in Cubic Feet of Gas per Hour 


10 


20 


42 


85 


148 


210 


448 


806 


1,271 


2,646 


4,682 


20 


14 


29 


58 


102 


144 


308 


554 


873 


1.819 


3,218 


30 


11 


23 


47 


82 


116 


247 


445 


701 


1,461 


2,584 


40 


10 


20 


40 


70 


99 


211 


381 


600 


1,250 


2,212 


50 


8.4 


17 


35 


62 


88 


187 


337 


532 


1,108 


1,960 


60 


7.6 


16 


32 


56 


79 


170 


306 


482 


1,004 


1,776 


70 


7.0 


14 


29 


52 


73 


156 


281 


443 


924 


1,634 


80 


6.5 


13 


27 


48 


68 


145 


262 


413 


859 


1,520 


90 


6.1 


13 


26 


45 


64 


136 


245 


387 


806 


1,426 


100 


5.8 


12 


24 


43 


60 


129 


232 


366 


761 


1,347 


125 


5.1 


11 


22 


38 


53 


114 


206 


324 


675 


1,194 


150 


4.7 


10 


20 


34 


48 


103 


186 


294 


612 


1,082 


175 


4.3 


8.8 


18 


31 


45 


95 


171 


270 


563 


995 


200 


4.0 


8.2 


17 


29 


41 


89 


159 


251 


523 


926 


250 


3.5 


7.3 


15 


26 


37 


78 


141 


223 


464 


821 


300 


3.2 


6.6 


13 


23 


33 


71 


128 


202 


420 


744 



^ Table capacities are based on Type K copper tubing inside diameter (shown ) , which has the smallest inside diameter of the 
copper tubing products. 



2002 Edition 



54^64 



NATIONAL FUEL GAS CODE 



ANSI Z223. 1-64 



Table 12.8 Semi-Rigid Copper Tubing 








Gas 


Natural 




Inlet pressure 


0.5 psi or less 




Pressure Drop 


0.5 in. w.c. 




Specific Gravity 


0.60 



Tube Size (in.) 





K&L 


'/4 


% 


1/2 


% 


3/4 


1 


l>/4 


11/2 


2 


2'/2 


Nominal 


ACR 


% 


V4 


% 


% 


% 


1V6 


1% 


15/8 


21/8 


2% 


Outside 


0.375 


0.500 


0.625 


0.750 


0.875 


1.125 


1.375 


1.625 


2.125 


2.625 


Inside' 


0.305 


0.402 


0.527 


0.652 


0.745 


0.995 


1.245 


1.481 


1.959 


2.435 


Length 
(ft) 


Maximum Capacity in Cubic Feet of Gas per Hour 


10 


27 


55 


111 


195 


276 


590 


1,062 


1,675 


3,489 


6,173 


20 


18 


38 


77 


134 


190 


406 


730 


1,151 


2,398 


4,242 


30 


15 


30 


61 


107 


152 


326 


586 


925 


1,926 


3,407 


40 


13 


26 


53 


92 


131 


279 


502 


791 


1,648 


2,916 


50 


11 


23 


47 


82 


116 


247 


445 


701 


1,461 


2,584 


60 


10 


21 


42 


74 


105 


224 


403 


635 


1,323 


2,341 


70 


9.3 


19 


39 


68 


96 


206 


371 


585 


1,218 


2,154 


80 


8.6 


18 


36 


63 


90 


192 


345 


544 


1,133 


2,004 


90 


8.1 


17 


34 


59 


84 


180 


324 


510 


1,063 


1,880 


100 


7.6 


16 


32 


56 


79 


170 


306 


482 


1,004 


1,776 


125 


6.8 


14 


28 


50 


70 


151 


271 


427 


890 


1,574 


150 


6.1 


13 


26 


45 


64 


136 


245 


387 


806 


1,426 


175 


5.6 


12 


24 


41 


59 


125 


226 


356 


742 


1,312 


200 


5.2 


11 


22 


39 


55 


117 


210 


331 


690 


1,221 


250 


4.7 


10 


20 


34 


48 


103 


186 


294 


612 


1,082 


300 


4.2 


8.7 


18 


31 


44 


94 


169 


266 


554 


980 



' Table capacities are based on Type K copper tubing inside diameter (shown), which has the smallest inside diameter of the 
copper tubing products. 



2002 Edition 



ANSI Z223. 1-65 



PIPE SIZING 



54-65 



Table 12.9 Semi-Rigid Copper Tubing 








Gas 


Natural 




Inlet pressure 


0.5 psi or less 




Pressure Drop 


1.0 in. w.c. 




Specific Gravity 


0.60 



SPECIAL USE: 



Use this Table to Size Tubing from House Line Regulator to the Appliance. 



Tube Size (in.) 





K&L 


'/4 


Ys 


'A 


5/8 


y4 


1 


11/4 


l'/2 


2 


2'/2 


Nominal 


ACR 


% 


'/4 


% 


% 


% 


V/s 


1% 


P/s 


2 '/a 


2% 


Outside 


0.375 


0.500 


0.625 


0.750 


0.875 


1.125 


1.375 


1.625 


2.125 


2.625 


Inside' 


0.305 


0.402 


0.527 


0.652 


0.745 


0.995 


1.245 


1.481 


1.959 


2.435 


Length 

(ft) 


Maximum Capacity in Cubic Feet of Gas per Hour 


10 


39 


80 


162 


283 


402 


859 


1,546 


2,437 


5,076 


8,981 


20 


27 


55 


111 


195 


276 


590 


1,062 


1,675 


3,489 


6,173 


30 


21 


44 


89 


156 


222 


474 


853 


1,345 


2,802 


4,957 


40 


18 


38 


77 


134 


190 


406 


730 


1,151 


2,398 


4,242 


50 


16 


33 


68 


119 


168 


359 


647 


1,020 


2,125 


3,760 


60 


15 


30 


61 


107 


152 


326 


586 


925 


1,926 


3,407 


70 


13 


28 


57 


99 


140 


300 


539 


851 


1,772 


3,134 


80 


13 


26 


53 


92 


131 


279 


502 


791 


1,648 


2,916 


90 


12 


24 


49 


86 


122 


262 


471 


742 


1,546 


2,736 


100 


11 


23 


47 


82 


116 


247 


445 


701 


1,461 


2,584 


125 


9.8 


20 


41 


72 


103 


219 


394 


622 


1,295 


2,290 


150 


8.9 


18 


37 


65 


93 


198 


357 


563 


1,173 


2,075 


175 


8.2 


17 


34 


60 


85 


183 


329 


518 


1,079 


1,909 


200 


7.6 


16 


32 


56 


79 


170 


306 


482 


1,004 


1,776 


250 


6.8 


14 


28 


50 


70 


151 


271 


427 


890 


1,574 


300 


6.1 


13 


26 


45 


64 


136 


245 


387 


806 


1,426 



' Table capacities are based on Type K copper tubing inside dijimeter (shown) , which has the smallest inside diameter of the 
copper tubing products. 



2002 Edition 



54-66 



NATIONAL FUEL GAS CODE 



ANSI Z223.1-66 



Table 12.10 Semi-Rigid Copper Tubing 








Gas 


Natural 




Inlet pressure 


2.0 psi or less 




Pressure Drop 


I7.0in. w.c. 




Specific Gravity 


0.60 



Tube Size (in.) 





K&L 


!/4 


% 


1/2 


Ya 


3/4 


1 


11/4 


VA 


2 


2'/2 


Nominal 


ACR 


% 


1/2 


5/8 


3/4 


% 


r/8 


P/s 


Wa 


21/8 


25/8 


Outside 


0.375 


0.500 


0.625 


0.750 


0.875 


1.125 


1.375 


1.625 


2.125 


2.625 


Inside' 


0.305 


0.402 


0.527 


0.652 


0.745 


0.995 


1.245 


1.481 


1.959 


2.435 


Length 

(ft) 








Maximum 


Capacity in Cubic Feet of Gas per Hour 








10 


190 


391 


796 


1,391 


1,974 


4,216 


7,591 


11,968 


24,926 


44,100 


20 


130 


269 


547 


956 


1,357 


2,898 


5,217 


8,226 


17,132 


30,310 


30 


105 


216 


439 


768 


1,089 


2,327 


4,189 


6,605 


13,757 


24,340 


40 


90 


185 


376 


657 


932 


1,992 


3,586 


5,653 


11,775 


20,832 


50 


79 


164 


333 


582 


826 


1,765 


3,178 


5,010 


10,436 


18,463 


60 


72 


148 


302 


528 


749 


1,599 


2,879 


4,540 


9,455 


16,729 


70 


66 


137 


278 


486 


689 


1,471 


2,649 


4,177 


8,699 


15,390 


80 


62 


127 


258 


452 


641 


1,369 


2,464 


3,886 


8,093 


14,318 


90 


58 


119 


243 


424 


601 


1,284 


2,312 


3,646 


7,593 


13,434 


100 


55 


113 


229 


400 


568 


1,213 


2,184 


3,444 


7,172 


12,689 


125 


48 


100 


203 


355 


503 


1,075 


1,936 


3,052 


6,357 


11,246 


150 


44 


90 


184 


321 


456 


974 


1,754 


2,765 


5,760 


10,190 


175 


40 


83 


169 


296 


420 


896 


1,614 


2,544 


5,299 


9,375 


200 


38 


77 


157 


275 


390 


834 


1,501 


2,367 


4,930 


8,721 


250 


33 


69 


140 


244 


346 


739 


1,330 


2,098 


4,369 


7,730 


300 


30 


62 


126 


221 


313 


670 


1,205 


1,901 


3,959 


7,004 



' Table capacities are based on Type K copper tubing inside diameter (shown), which has the smallest inside diameter of the 
copper tubing products. 



2002 Edition 



ANSI Z223. 1-67 



PIPE SIZING 



54-67 



Table 12.11 Semi-Rigid Copper Tubing 








Gas 


Natural 




Inlet pressure 


2.0 psi or less 




Pressure Drop 


1.0 psi 




Specific Gravity 


0.60 



Tube Size (in.) 





K&L 


Va 


% 


W 


5/8 


% 


1 


VA 


VA 


2 


2Vz 


Nominal 


ACR 


3/8 


'A 


5/8 


% 


Vi 


l'/8 


l-Vs 


Ws 


2'/8 


2% 


Outside 


0.375 


0.500 


0.625 


0.750 


0.875 


1.125 


1.375 


1.625 


2.125 


2.625 


Inside' 


0.305 


0.402 


0.527 


0.652 


0.745 


0.995 


1.245 


1.481 


1.959 


2.435 


Length 

(ft) 








Maximum 


Capacity in Cubic Feet of Gas per Hour 








10 


245 


506 


1,030 


1,800 


2,554 


5,455 


9,820 


15,483 


32,247 


57,051 


20 


169 


348 


708 


1,237 


1,755 


3,749 


6,749 


10,641 


22,163 


39,211 


30 


135 


279 


568 


993 


1,409 


3,011 


5,420 


8,545 


17,798 


31,488 


40 


116 


239 


486 


850 


1,206 


2,577 


4,639 


7,314 


15,232 


26,949 


50 


103 


212 


431 


754 


1,069 


2,284 


4,111 


6,482 


13,500 


23,885 


60 


93 


192 


391 


683 


969 


2,069 


3,725 


5,873 


12,232 


21,641 


70 


86 


177 


359 


628 


891 


1,904 


3,427 


5,403 


11,253 


19,910 


80 


80 


164 


334 


584 


829 


1,771 


3,188 


5,027 


10,469 


18,522 


90 


75 


154 


314 


548 


778 


1,662 


2,991 


4,716 


9,823 


17,379 


100 


71 


146 


296 


518 


735 


1,570 


2,826 


4:Abb 


9,279 


16,416 


125 


63 


129 


263 


459 


651 


1,391 


2.504 


3,948 


8,223 


14,549 


150 


57 


117 


238 


416 


590 


1,260 


2,269 


3,577 


7,451 


13,183 


175 


52 


108 


219 


383 


543 


1,160 


2,087 


3,291 


6,855 


12,128 


200 


49 


100 


204 


356 


505 


1,079 


1,942 


3,062 


6,377 


11,283 


250 


43 


89 


181 


315 


448 


956 


1,721 


2,714 


5,652 


10,000 


300 


39 


80 


164 


286 


406 


866 


1,559 


2,459 


5,121 


9,060 



' Table capacities are based on Type K copper tubing inside diameter (shown) , which has the smallest inside diameter of the 
copper tubing products. 



2002 Edition 



54-68 



NATIONAL FUEL GAS CODE 



ANSI Z223. 1-68 



Table 12.12 Semi-Rigid Copper Tubing 








Gas 


Natural 




Inlet pressure 


2.0 psi 




Pressure Drop 


1.5 psi 




Specific Gravity 


0.60 


SPECIAL USE: 


Pipe Sizing Between Point of Delivery and the House Line Regulator. Total Load Supplied by a Single House Line Regulator not 
Exceeding 150 Cubic Feet per Hour. 



Tube Size (in.) 





K&L 


1/4 


% 


'/2 


% 


3/4 


1 


l'/4 


l'/2 


2 


2'/2 


Nominal 


ACR 


3/8 


Vi 


Vs 


% 


Vs 


I'/s 


1% 


P/s 


21/8 


2% 


Outside 


0.375 


0.500 


0.625 


0.750 


0.875 


1.125 


1.375 


1.625 


2.125 


2.625 


Inside' 


0.305 


0.402 


0.527 


0.652 


0.745 


0.995 


1.245 


1.481 


1.959 


2.435 


Length 

(ft) 


Maximum Capacity in Cubic Feet of Gas per Hour 


10 


303 


625 


1,272 


2,224 


3,155 


6,739 


12,131 


19,127 


39,837 


70,481 


20 


208 


430 


874 


1,528 


2,168 


4,631 


8,338 


13,146 


27,380 


48,441 


30 


167 


345 


702 


1,227 


1,741 


3,719 


6,696 


10,557 


21,987 


38,900 


40 


143 


295 


601 


1,050 


1,490 


3,183 


5,731 


9,035 


18,818 


33,293 


50 


127 


262 


533 


931 


1,321 


2,821 


5,079 


8,008 


16,678 


29,507 


60 


115 


237 


483 


843 


1,197 


2,556 


4,602 


7,256 


15,112 


26,736 


70 


106 


218 


444 


776 


1,101 


2,352 


4,234 


6,675 


13,903 


24,597 


80 


98 


203 


413 


722 


1,024 


2,188 


3,939 


6,210 


12,934 


22,882 


90 


92 


191 


388 


677 


961 


2,053 


3,695 


5,826 


12,135 


21,470 


100 


87 


180 


366 


640 


908 


1,939 


3,491 


5,504 


11,463 


20,280 


125 


77 


159 


324 


567 


804 


1,718 


3,094 


4,878 


10,159 


17,974 


150 


70 


145 


294 


514 


729 


1,557 


2,803 


4,420 


9,205 


16,286 


175 


64 


133 


270 


473 


671 


1,432 


2,579 


4,066 


8,469 


14,983 


200 


60 


124 


252 


440 


624 


1,333 


2,399 


3,783 


7,878 


13,938 


250 


53 


110 


223 


390 


553 


1,181 


2,126 


3,352 


6,982 


12,353 


300 


48 


99 


202 


353 


501 


1,070 


1,927 


3,038 


6,327 


11,193 



' Table capacities are based on Type K copper tubing inside diameter (shown ) , which has the smallest inside diameter of the 
copper tubing products. 

^ When this table is used to size the tubing upstream of a line pressure regulator, the pipe or tubing downstream of the line 
pressure regulator shall be sized using a pressure drop no greater than 1 in. w.c. 



2002 Edition 



ANSI Z223. 1-69 



PIPE SIZING 



54-69 



Table 12.13 Semi-Rigid Copper Tubing 








Gas 


Natural 




Inlet pressure 


5.0 psi or less 




Pressure Drop 


3.5 psi 




Spedfic Gravity 


0.60 



Tube Size (in.) 





K&L 


'/4 


3/8 


V& 


s/s 


3/4 


1 


l'/4 


l'/2 


2 


2'/i 


Nominal 


ACR 


% 


¥2 


Vs 


y4 


% 


\V% 


P/s 


15/8 


2V8 


2% 


Outside 


0.375 


0.500 


0.625 


0.750 


0.875 


1.125 


1.375 


1.625 


2.125 


2.625 


Inside' 


0.305 


0.402 


0.527 


0.652 


0.745 


0.995 


1.245 


1.481 


1.959 


2.435 


Length 

(ft) 








Maximum 


Capacity in Cubic Feet of Gas per Hour 








10 


511 


1,054 


2,144 


3,747 


5,315 


11,354 


20,441 


32,229 


67,125 


118,758 


20 


351 


724 


1,473 


2,575 


3,653 


7,804 


14,049 


22,151 


46,135 


81,622 


30 


282 


582 


1,183 


2,068 


2,934 


6,267 


11,282 


17,788 


37,048 


65,545 


40 


241 


498 


1,013 


1,770 


2,511 


5,364 


9,656 


15,224 


31,708 


56,098 


50 


214 


441 


898 


1,569 


2,225 


4,754 


8,558 


13,493 


28,102 


49,719 


60 


194 


400 


813 


1,421 


2,016 


4,307 


7,754 


12,225 


25,463 


45,049 


70 


178 


368 


748 


1,308 


1,855 


3,962 


7,134 


11,247 


23,425 


41,444 


80 


166 


342 


696 


1,216 


1,726 


3,686 


6,636 


10,463 


21,793 


38,556 


90 


156 


321 


653 


1,141 


1,619 


3,459 


6,227 


9,817 


20,447 


36,176 


100 


147 


303 


617 


1,078 


1,529 


3,267 


5,882 


9,273 


19,315 


34,172 


125 


130 


269 


547 


955 


1,356 


2,896 


5,213 


8,219 


17,118 


30,286 


150 


118 


243 


495 


866 


1,228 


2,624 


4,723 


7,447 


15,510 


27,441 


175 


109 


224 


456 


796 


1,130 


2,414 


4,345 


6,851 


14,269 


25,245 


200 


101 


208 


424 


741 


1,051 


2,245 


4,042 


6,374 


13,275 


23,486 


250 


90 


185 


376 


657 


932 


1,990 


3,583 


5,649 


11,765 


20,815 


300 


81 


167 


340 


595 


844 


1,803 


3,246 


5,118 


10,660 


18,860 



' Table capacities are based on Type K copper tubing inside diameter (shown) , which has the smallest inside diameter of the 
copper tubing products. 



2002 Edition 



54-70 



NATIONAL FUEL GAS CODE 



ANSI Z223.1-70 



Table 12.14 Corrugated Stainless Steel Tubing (CSST) 








Gas 


Natural 




Inlet pressure 


0.5 psi or less 




Pressure Drop 


0.5 in. w.c. 




Specific Gravity 


0.60 



Tube Size (EHD)* 



Flow 
Designation: 


13 


15 


18 


19 


23 


25 


30 


31 


37 


46 


62 


Length 

(ft) 


Maximiun Capacity in Cubic Feet of Gas per Hoiu- 


5 


46 


63 


115 


134 


225 


270 


471 


546 


895 


1,790 


4,142 


10 


32 


44 


82 


95 


161 


192 


330 


383 


639 


1,261 


2,934 


15 


25 


35 


66 


77 


132 


157 


267 


310 


524 


1,027 


2,398 


20 


22 


31 


58 


67 


116 


137 


231 


269 


456 


888 


2,078 


25 


19 


27 


52 


60 


104 


122 


206 


240 


409 


793 


1,860 


30 


18 


25 


47 


55 


96 


112 


188 


218 


374 


723 


1,698 


40 


15 


21 


41 


47 


83 


97 


162 


188 


325 


625 


1,472 


50 


13 


19 


37 


42 


75 


87 


144 


168 


292 


559 


1,317 


60 


12 


17 


34 


38 


68 


80 


131 


153 


267 


509 


1,203 


70 


11 


16 


31 


36 


63 


74 


121 


141 


248 


471 


1,114 


80 


10 


15 


29 


33 


60 


69 


113 


132 


232 


440 


1,042 


90 


10 


14 


28 


32 


57 


65 


107 


125 


219 


415 


983 


100 


9 


13 


26 


30 


54 


62 


101 


118 


208 


393 


933 


150 


7 


10 


20 


23 


42 


48 


78 


91 


171 


320 


762 


200 


6 


9 


18 


21 


38 


44 


71 


82 


148 


277 


661 


250 


5 


8 


16 


19 


34 


39 


63 


74 


133 


247 


591 


300 


5 


7 


15 


17 


32 


36 


57 


67 


95 


226 


540 



Note: Table includes losses for four 90-degree bends and two end fittings. Tubing runs with larger numbers of bends and/or 
fittings shall be increased by an equivalent length of tubing to the following equation: L = 1.3n, where L is additional length 
(ft) of tubing and n is the nun:iber of additional fittings and/or bends. 

*EHD = Equivalent Hydraulic Diameter, which is a measure of the relative hydraulic efficiency between dijBFerent tubing 
sizes. The greater the value of EHD, the greater the gas capacity of the tubing. 



2002 Edition 



ANSI Z223.1-71 



PIPE SIZING 



54-71 



Table 12.15 Corrugated Stainless Steel Tubing (CSST) 








Gas 


Natural 




Inlet pressure 


0.5 psi or less 




Pressure Drop 


3.0 in. w.c. 




Specific Gravity 


0.60 



Tube Size (EHD)* 



Flow 
Designation: 


13 


15 


18 


19 


23 


25 


30 


31 


37 


46 


62 


Length 

(ft) 


Maximum Capacity in Cubic Feet of Gas per Hour 


5 


120 


160 


277 


327 


529 


649 


1,182 


1,365 


2,141 


4,428 


10,103 


10 


83 


112 


197 


231 


380 


462 


828 


958 


1,528 


3,199 


7,156 


15 


67 


90 


161 


189 


313 


379 


673 


778 


1,254 


2,541 


5,848 


20 


57 


78 


140 


164 


273 


329 


580 


672 


1,090 


2,197 


5,069 


25 


51 


69 


125 


147 


245 


295 


518 


599 


978 


1,963 


4,536 


30 


46 


63 


115 


134 


225 


270 


471 


546 


895 


1,790 


4,142 


40 


39 


54 


100 


116 


196 


234 


407 , 


471 


778 


1,548 


3,590 


50 


35 


48 


89 


104 


176 


210 


363 


421 


698 


1,383 


3,213 


60 


32 


44 


82 


95 


161 


192 


330 


383 


639 


1,261 


2,934 


70 


29 


41 


76 


88 


150 


178 


306 


355 


593 


1,166 


2,717 


80 


27 


38 


71 


82 


141 


167 


285 


331 


555 


1,090 


2,543 


90 


26 


36 


67 


77 


133 


157 


268 


311 


524 


1,027 


2,398 


100 


24 


34 


63 


73 


126 


149 


254 


295 


498 


974 


2,276 


150 


19 


27 


52 


60 


104 


122 


206 


240 


409 


793 


1,860 


200 


17 


23 


45 


52 


91 


106 


178 


207 


355 


686 


1,612 


250 


15 


21 


40 


46 


82 


95 


159 


184 


319 


613 


1,442 


300 


13 


19 


37 


42 


75 


87 


144 


168 


234 


559 


1,317 



Note: Table includes losses for four 90-degree bends and two end fittings. Tubing runs with larger numbers of bends and/or 
fittings shall be increased by an equivalent length of tubing to the following equation: L = 1 .3n, where L is additional length 
(ft) of tubing and n is the number of additional fittings and/or bends. 

*EHD = Equivalent Hydraulic Diameter, which is a measure of the relative hydraulic efificiency between different tubing 
sizes. The greater the value of EHD, the greater the gas capacity of the tubing. 



2002 Edition 



54-72 



NATIONAL FUEL GAS CODE 



ANSI Z223.1-72 



Table 12.16 Corrugated Stainless Steel Tubing (CSST) 








Gas 


Natural 




Inlet pressure 


0.5 ]jsi or less 




Pressure Drop 


6.0 in. w.c. 




Specific Gravity 


0.60 



Tube Size (EHD)* 



Flow 
Designation: 


13 


15 


18 


19 


23 


25 


30 


31 


37 


46 


62 


Length 

(ft) 


Maximum Capacity in Cubic Feet of Gas per Hour 


5 


173 


229 


389 


461 


737 


911 


1,687 


1,946 


3,000 


6.282 


14,263 


10 


120 


160 


277 


327 


529 


649 


1,182 


1,365 


2,141 


4,428 


10,103 


15 


96 


130 


227 


267 


436 


532 


960 


1,110 


1,758 


3,607 


8,257 


20 


83 


112 


197 


231 


380 


462 


828 


958 


1,528 


3,119 


7,156 


25 


74 


99 


176 


207 


342 


414 


739 


855 


1,371 


2,786 


6,404 


30 


67 


90 


161 


189 


313 


379 


673 


778 


1,254 


2,541 


5,848 


40 


57 


78 


140 


164 


273 


329 


580 


672 


1,090 


2,197 


5,069 


50 


51 


69 


125 


147 


245 


295 


518 


599 


978 


1,963 


4,536 


60 


46 


63 


115 


134 


225 


270 


471 


546 


895 


1,790 


4,142 


70 


42 


58 


106 


124 


209 


250 


435 


505 


830 


1,656 


3,837 


80 


39 


54 


100 


116 


196 


234 


407 


471 


778 


1,548 


3,590 


90 


37 


51 


94 


109 


185 


221 


383 


444 


735 


1,458 


3,386 


100 


35 


48 


89 


104 


176 


210 


363 


421 


698 


1,383 


3,213 


150 


28 


39 


73 


85 


145 


172 


294 


342 


573 


1,126 


2,626 


200 


24 


34 


63 


73 


126 


149 


254 


295 


498 


974 


2,276 


250 


21 


30 


57 


66 


114 


134 


226 


263 


447 


870 


2,036 


300 


19 


27 


52 


60 


104 


122 


206 


240 


409 


793 


1,860 



Note: Table includes losses for four 90-degree bends and two end fittings. Tubing runs with larger numbers of bends and/or 
fittings shall be increased by an equivalent length of tubing to the following equation: L = 1 .3n, where L is additional length 
(ft) of tubing and n is the number of additional fittings and/or bends. 

*EHD = Equivalent Hydraulic Diameter, which is a measure of the relauve hydraulic efficiency between different tubing 
sizes. The greater the value of EHD, the greater the gas capacity of the tubing. 



2002 Edition 



ANSI Z223. 1-73 



PIPE SIZING 



54-73 



Table 12.17 Corrugated Stainless Steel Tubing (CSST) 



Gas 



Inlet pressure 



Pressure Drop 



Specific Gravity 



Natural 



2.0 psi 



1.0 psi 



0.60 



Tube Size (EHD)* 



Flow 
Designation: 


13 


15 


18 


19 


23 


25 


30 


31 


37 


46 


62 


Length 

(ft) 


Maximum Capacity in Cubic Feet of Gas per Hour 


10 


270 


353 


587 


700 


1,098 


1,372 


2,592 


2,986 


4,509 


9,599 


21,637 


25 


166 


220 


374 


444 


709 


876 


1,620 


1,869 


2,887 


6,041 


13,715 


30 


151 


200 


342 


405 


650 


801 


1,475 


1,703 


2,642 


5,509 


12.526 


40 


129 


172 


297 


351 


567 


696 


1,273 


1,470 


2,297 


4,763 


10,855 


50 


115 


154 


266 


314 


510 


624 


1,135 


1,311 


2,061 


4,255 


9,715 


75 


93 


124 


218 


257 


420 


512 


922 


1,066 


1,692 


3,467 


7,940 


80 


89 


120 


211 


249 


407 


496 


892 


1,031 


1,639 


3,355 


7,689 


100 


79 


107 


189 


222 


366 


445 


795 


920 


1,471 


2,997 


6,881 


150 


64 


87 


155 


182 


302 


364 


646 


748 


1,207 


2,442 


5,624 


200 


55 


75 


135 


157 


263 


317 


557 


645 


1,049 


2,111 


4,874 


250 


49 


67 


121 


141 


236 


284 


497 


576 


941 


1,886 


4,362 


300 


44 


61 


110 


129 


217 


260 


453 


525 


862 


1,720 


3,983 


400 


38 


52 


96 


111 


189 


225 


390 


453 


749 


1,487 


3,452 


500 


34 


46 


86 


100 


170 


202 


348 


404 


552 


1,329 


3,089 



Notes: 

1 . Table does not include effect of pressure drop across the line regulator. Where regulator loss exceeds 54 psi, do not use this 
table. Consult with regulator manufacturer for pressure drops and capacity factors. Pressure drops across a regulator may 
vary with flow rate. 

2. CAUTION: Capacities shown in table may exceed maximum capacity for a selected regulator. Consult with regulator or 
tubing manufacturer for guidance. 

3. Table includes losses for four 90-degree bends and two end fittings. Tubing runs with larger number of bends and/or 
fittings shall be increased by an equivalent length of tubing according to the following equation: L = 1.3w, where L is 
additional length (ft) of tubing and n is the number of additional fittings and/or bends. 

*EHD = Equivalent Hydrauhc Diameter, which is a measure of the relative hydraulic efficiency between different tubing 
sizes. The greater the value of EHD, the greater the gas capacity of the tubing. 



2002 Edition 



54-74 



NATIONAL FUEL GAS CODE 



ANSI Z223. 1-74 



Table 12.18 Corrugated Stainless Steel Tubing (CSST) 



Gas 



Inlet pressure 



Pressure Drop 



Specific Gravity 



Natural 



5.0 psi 



3.5 psi 



0.60 



Tube Size (EHD)* 



Flow 
Designation: 


13 


15 


18 


19 


23 


25 


30 


31 


37 


46 


62 


Length 
(ft) 








Maximum Capaci 


ty in Cubic Feet of Gas per 


Hour 








10 


523 


674 


1,084 


1,304 


1,995 


2,530 


4,923 


5,659 


8,295 


18,080 


40,353 


25 


322 


420 


691 


827 


1,289 


1,616 


3,077 


3,543 


5,311 


11,378 


25,580 


30 


292 


382 


632 


755 


1,181 


1,478 


2,803 


3,228 


4,860 


10,377 


23,361 


40 


251 


329 


549 


654 


1,031 


1,284 


2,418 


2,786 


4,225 


8,972 


20,246 


50 


223 


293 


492 


586 


926 


1,151 


2,157 


2,486 


3,791 


8,015 


18,119 


75 


180 


238 


403 


479 


763 


944 


1,752 


2,021 


3,112 


6,530 


14,809 


80 


174 


230 


391 


463 


740 


915 


1,694 


1,955 


3,016 


6,320 


14,341 


100 


154 


205 


350 


415 


665 


820 


1,511 


1,744 


2,705 


5,646 


12,834 


150 


124 


166 


287 


339 


548 


672 


1,228 


1,418 


2,221 


4,600 


10,489 


200 


107 


143 


249 


294 


478 


584 


1,060 


1,224 


1,931 


3,977 


9,090 


250 


95 


128 


223 


263 


430 


524 


945 


1,092 


1,732 


3,553 


8,135 


300 


86 


116 


204 


240 


394 


479 


860 


995 


1,585 


3,240 


7,430 


400 


74 


100 


177 


208 


343 


416 


742 


858 


1,378 


2,802 


6,439 


500 


66 


89 


159 


186 


309 


373 


662 


766 


1,035 


2,503 


5,762 



Notes: 

1. Table does not include effect of pressure drop across line regulator. Where regulator loss exceeds 1 psi, do not use this 
table. Consult with regulator manufacturer for pressure drops and capacity factors. Pressure drop across regulator may vary 
with the flow rate. 

2. CAUTION: Capacities shown in table may exceed maximum capacity of selected regulator. Consult with tubing manufac- 
turer for guidance. 

3. Table includes losses for four 90-degree bends and two end fittings. Tubing runs with larger numbers of bends and/or 
fittings shall be increased by an equivalent length of tubing to the following equation: L= 1.3n, where L is additional length 
(ft) of tubing and n is the number of additional fittings and/or bends. 

*EHD = Equivalent Hydraulic Diameter, which is a measure of the relative hydraulic efficiency between different tubing 
sizes. The greater the value of EHD, the greater the gas capacity of the tubing. 



2002 Edition 



ANSI Z223. 1-75 



PIPE SIZING 



54-75 



Table 12.19 Polyethylene Plastic Pipe 








Gas 


Natural 




Inlet pressure 


1.0 psi or Less 




Pressure Drop 


0.3 in. w.c. 




Specific Gravity 


0.60 



Pipe Size (in.) 



Nominal OD 


V2 


3/4 


1 


VA 


VA 


2 


Designation: 


SDR 9.33 


SDR 11.0 


SDR 11.00 


SDR 10.00 


SDR 11.00 


SDR 11.00 


Actual ID 


0.660 


0.860 


1.077 


1.328 


1.554 


1.943 


Length 

(ft) 


Maximum Capacity in Cubic Feet of Gas per Hour 


10 


153 


305 


551 


955 


1,442 


2,590 


20 


105 


210 


379 


656 


991 


1,780 


30 


84 


169 


304 


527 


796 


1,430 


40 


72 


144 


260 


451 


681 


1,224 


50 


64 


128 


231 


400 


604 


1,084 


60 


58 


116 


209 


362 


547 


983 


70 


53 


107 


192 


333 


503 


904 


80 


50 


99 


179 


310 


468 


841 


90 


46 


93 


168 


291 


439 


789 


100 


44 


88 


159 


275 


415 


745 


125 


39 


78 


141 


243 


368 


661 


150 


35 


71 


127 


221 


333 


598 


175 


32 


65 


117 


203 


306 


551 


200 


30 


60 


109 


189 


285 


512 



2002 Edition 



54-76 



NATIONAL FUEL GAS CODE 



ANSI Z223.1-76 



Table 12.20 Polyethylene Plastic Pipe 



Gas 



Inlet pressure 



Pressure Drop 



Specific Gravity 



Natural 



1.0 psi or Less 



0.5 in. w.c. 



0.60 



Pipe Size (in.) 



Nominal OD 


>/2 


% 


1 


l'/4 


VA 


2 


Designation: 


SDR 9.33 


SDR 11.0 


SDR 11.00 


SDR 10.00 


SDR 11.00 


SDR 11.00 


Actual ID 


0.660 


0.860 


1.077 


1.328 


1.554 


1.943 


Length 

(ft) 


Maximum Capacity in Cubic Feet of Gas per Hour 


10 


201 


403 


726 


1,258 


1,900 


3,415 


20 


138 


277 


499 


865 


1,306 


2,347 


30 


111 


222 


401 


695 


1,049 


1,885 


40 


95 


190 


343 


594 


898 


1,613 


50 


84 


169 


304 


527 


796 


1,430 


60 


76 


153 


276 


477 


721 


1,295 


70 


70 


140 


254 


439 


663 


1,192 


80 


65 


131 


236 


409 


617 


1,109 


90 


61 


123 


221 


383 


579 


1,040 


100 


58 


116 


209 


362 


547 


983 


125 


51 


103 


185 


321 


485 


871 


150 


46 


93 


168 


291 


439 


789 


175 


43 


86 


154 


268 


404 


726 


200 


40 


80 


144 


249 


376 


675 



2002 Edition 



ANSI Z223. 1-77 



PIPE SIZING 



54-77 



Table 12.21 Polyethylene Plastic Pipe 



Gas 



Inlet pressure 



Pressure Drop 



Specific Gravity 



Natural 



2.0 psi 



1.0 psi 



0.60 



Pipe Size (in.) 



Nominal OD 


'/2 


3/4 


1 


l'/4 


11/2 


2 


Designation: 


SDR 9.33 


SDR 11.0 


SDR 11.00 


SDR 10.00 


SDR 11.00 


SDR 11.00 


Actual ID 


0.660 


0.860 


1.077 


1.328 


1.554 


1.943 


Length 

(ft) 


Maximum Capacity in Cubic Feet of Gas per Hour 


10 


1,858 


3,721 


6,714 


11,631 


17,565 


31,560 


20 


1,277 


2,557 


4,614 


7,994 


12,072 


21,691 


30 


1,026 


2,054 


3,706 


6,420 


9,695 


17,419 


40 


878 


1,758 


3,172 


5,494 


8,297 


14,908 


50 


778 


1,558 


2,811 


4,869 


7,354 


13,213 


60 


705 


1,412 


2,547 


4,412 


6,663 


11,972 


70 


649 


1,299 


2,343 


4,059 


6,130 


11,014 


80 


603 


1,208 


2,180 


3,776 


5,703 


10,246 


90 


566 


1,134 


2,045 


3,543 


5,351 


9,614 


100 


535 


1,071 


1,932 


3,347 


5,054 


9,081 


125 


474 


949 


1,712 


2,966 


4,479 


8,048 


150 


429 


860 


1,551 


2,688 


4,059 


7,292 


175 


395 


791 


1,427 


2,473 


3,734 


6,709 


200 


368 


736 


1,328 


2,300 


3,474 


6,241 



2002 Edition 



54-78 



NATIONAL FUEL GAS CODE 



ANSI Z223. 1-78 



Table 12.22 Schedule 40 Metallic Pipe 








Gas 


Undiluted Propane 




Inlet pressure 


10.0 psi 




Pressure Drop 


1.0 psi 




Specific Gravity 


1.50 


SPECIAL 
USE: 


Pipe Sizing Between First Stage (High Pressure Regulator) and Second Stage (Low Pressure Regulator) 



Pipe Size (in.) 



Nominal 
Inside 


!/2 


% 


1 


VA 


l'/2 


2 


3 


3'/2 


4 


Actual 


0.622 


0.824 


1.049 


1.38 


1.61 


2.067 


3.068 


3.548 


4.026 


Length 

(ft) 


Maximum Capacity in Thousands of Btu per Hour 


30 


1,834 


3,835 


7,225 


14,834 


22,225 


42,804 


120,604 


176,583 


245,995 


40 


1,570 


3,283 


6,184 


12,696 


19,022 


36,634 


103,222 


151,132 


210,539 


50 


1,391 


2,909 


5,480 


11,252 


16,859 


32,468 


91,484 


133,946 


186,597 


60 


1,261 


2,636 


4,966 


10,195 


15,275 


29,419 


82,891 


121,364 


169,071 


70 


1,160 


2,425 


4,568 


9,379 


14,053 


27,065 


76,258 


111,654 


155,543 


80 


1,079 


2,256 


4,250 


8,726 


13,074 


25,179 


70,944 


103,872 


144,703 


90 


1,012 


2,117 


3,988 


8,187 


12,267 


23,624 


66,564 


97,460 


135,770 


100 


956 


2,000 


3,767 


7,733 


11,587 


22,315 


62,876 


92,060 


128,247 


150 


768 


1,606 


3,025 


6,210 


9,305 


17,920 


50,492 


73,927 


102,987 


200 


657 


1,374 


2,589 


5,315 


7,964 


15,337 


43,214 


63,272 


88,144 


250 


582 


1,218 


2,294 


4,711 


7,058 


13,593 


38,300 


56,077 


78,120 


300 


528 


1,104 


2,079 


4,268 


6,395 


12,316 


34,703 


50,810 


70,782 


350 


486 


1,015 


1,913 


3,927 


5,883 


11,331 


31,926 


46,744 


65,119 


400 


452 


945 


1,779 


3,653 


5,473 


10,541 


29,701 


43,487 


60,581 


450 


424 


886 


1,669 


3,428 


5,135 


9,890 


27,867 


40,802 


56,841 


500 


400 


837 


1,577 


3,238 


4,851 


9,342 


26,323 


38,541 


53,691 


600 


363 


759 


1,429 


2,934 


4,395 


8,465 


23,851 


34,921 


48,648 


700 


334 


698 


1,314 


2,699 


4,044 


7,788 


21,943 


32,127 


44,756 


800 


310 


649 


1,223 


2,511 


3,762 


7,245 


20,413 


29,888 


41,637 


900 


291 


609 


1,147 


2,356 


3,530 


6,798 


19,153 


28,043 


39,066 


1,000 


275 


575 


1,084 


2,225 


3,334 


6,421 


18,092 


26,489 


36,902 


1,500 


221 


462 


870 


1,787 


2,677 


5,156 


14,528 


21,272 


29,633 


2,000 


189 


395 


745 


1,529 


2,291 


4,413 


12,4,35 


18,206 


25,362 



2002 Edition 



ANSI Z223. 1-79 



PIPE SIZING 



54-79 



Table 12.23 Schedule 40 Metallic Pipe 








Gas 


Undiluted Propane 




Inlet pressure 


2.0 psi 




Pressure Drop 


1.0 psi 




Specific Gravity 


1.50 



Pipe Size (in.) 



Nominal 


'A 


y4 


1 


l'/4 


VA 


2 


2'/2 


3 


4 


Actual ID 


0.622 


0.824 


1.049 


1.380 


1.610 


2.067 


2.469 


3.068 


4.026 


Length 

(ft) 


Maximum Capacity in Thousands of Btu per Hour 


10 


2,676 


5,595 


10,539 


21,638 


32,420 


62,438 


99,516 


175,927 


358,835 


20 


1,839 


3,845 


7,243 


14,872 


22,282 


42,913 


68,397 


120,914 


246,625 


30 


1,477 


3,088 


5,817 


11,942 


17,893 


34,461 


54,925 


97,098 


198,049 


40 


1,264 


2,643 


4,978 


10,221 


15,314 


29,494 


47,009 


83,103 


169,504 


50 


1,120 


2,342 


4,412 


9,059 


13,573 


26,140 


41,663 


73,653 


150,229 


60 


1,015 


2,122 


3,998 


8,208 


12,298 


23,685 


37,750 


66,735 


136,118 


70 


934 


1,952 


3,678 


7,551 


11,314 


21,790 


34,729 


61,395 


125,227 


80 


869 


1,816 


3,422 


7,025 


10,526 


20,271 


32,309 


57,116 


116,499 


90 


815 


1,704 


3,210 


6,591 


9,876 


19,020 


30,314 


53,590 


109,307 


100 


770 


1,610 


3,033 


6,226 


9,329 


17,966 


28,635 


50,621 


103,251 


125 


682 


1,427 


2,688 


5,518 


8,268 


15,923 


25,378 


44,865 


91,510 


150 


618 


1,293 


2,435 


5,000 


7,491 


14,427 


22,995 


40,651 


82,914 


175 


569 


1,189 


2,240 


4,600 


6,892 


13,273 


21,155 


37,398 


76,280 


200 


529 


1,106 


2,084 


4,279 


6,411 


12,348 


19,681 


34,792 


70,964 



2002 Edition 



54-80 



NATIONAL FUEL GAS CODE 



ANSI Z223. 1-80 



Table 12.24 Schedule 40 Metallic Pipe 








Gas 


Undiluted Propane 




Inlet pressure 


11.0 in. w.c. 




Pressure Drop 


0.5 in. w.c. 




Specific Gravity 


1.50 


SPECIAL 
USE: 


Pipe Sizing Between Single or Second Stage (Low Pressure Regulator) and Appliance. 



Pipe Size (in.) 



Nominal 
Inside 


'/2 


% 


1 


VA 


l'/2 


2 


3 


3'/2 


4 


Actual: 


0.622 


0.824 


1.049 


1.38 


1.61 


2.067 


3.068 


3.548 


4.026 


Length 

(ft) 


Maximum Capacity in Thousands of Btu per Hoiu- 


10 


291 


608 


1,145 


2,352 


3,523 


6,786 


19,119 


27,993 


38,997 


20 


200 


418 


787 


1,616 


2,422 


4,664 


13,141 


19,240 


26,802 


30 


160 


336 


632 


1,298 


1,945 


3,745 


10,552 


15,450 


21,523 


40 


137 


287 


541 


1,111 


1,664 


3,205 


9,031 


13,223 


18,421 


50 


122 


255 


480 


984 


1,475 


2,841 


8,004 


11,720 


16,326 


60 


110 


231 


434 


892 


1,337 


2,574 


7,253 


10,619 


14,793 


80 


94 


197 


372 


763 


1,144 


2,203 


6,207 


9,088 


12,661 


100 


84 


175 


330 


677 


1,014 


1,952 


5,501 


8,055 


11,221 


125 


74 


155 


292 


600 


899 


1,730 


4,876 


7,139 


9,945 


150 


67 


140 


265 


543 


814 


1,568 


4,418 


6,468 


9,011 


200 


58 


120 


227 


465 


697 


1,342 


3,781 


5,536 


7,712 


250 


51 


107 


201 


412 


618 


1,189 


3,351 


4,906 


6,835 


300 


46 


97 


182 


373 


560 


1,078 


3,036 


4,446 


6,193 


350 


42 


89 


167 


344 


515 


991 


2,793 


4,090 


5,698 


400 


40 


83 


156 


320 


479 


922 


2,599 


3,805 


5,301 



2002 Edition 



ANSI Z223. 1-81 



PIPE SIZING 



54-81 



Table 12.25 Semi-Rigid Copper Tubing 








Gas 


Undiluted Propane 




Inlet pressure 


10.0 psi 




Pressure Drop 


1.0 psi 




Spedfic Gravity 


1.50 


SPECIAL 
USE: 


Sizing Between First Stage (High Pressure Regulator) and Second Stage (Low Pressiu-e Regulator) 



Tube Size (in.) 





K&L 


'/4 


% 


V2 


s/g 


% 


1 


VA 


VA 


2 


2'A 


Nominal 


ACR 


% 


'A 


Vs 


% 


'/s 


l'/8 


1% 


15/8 


2V8 


2% 


Outside 


0.375 


0.500 


0.625 


0.750 


0.875 


1.125 


1.375 


1.625 


2.125 


2.625 


Inside' 


0.305 


0.402 


0.527 


0.652 


0.745 


0.995 


1.245 


1.481 


1.959 


2.435 


Length 

(ft) 








Maximum 


Capacity in Thousands of Btu per Hour 








10 


513 


1,058 


2,152 


3,760 


5,335 


11,396 


20,516 


32,347 


67,371 


119,193 


20 


352 


727 


1,479 


2,585 


3,667 


7,832 


14,101 


22,232 


46,303 


81,921 


30 


283 


584 


1,188 


2,075 


2,944 


6,290 


11,323 


17,853 


37,183 


65,785 


40 


242 


500 


1,016 


1,776 


2,520 


5,383 


9,691 


15,280 


31,824 


56,304 


50 


215 


443 


901 


1,574 


2,234 


4,771 


8,589 


13,542 


28,205 


49,901 


60 


194 


401 


816 


1,426 


2,024 


4,323 


7,782 


12,270 


25,556 


45,214 


70 


179 


369 


751 


1,312 


1,862 


3,977 


7,160 


11,288 


23,511 


41,596 


80 


166 


343 


699 


1,221 


1,732 


3,700 


6,661 


10,502 


21,873 


38,697 


90 


156 


322 


655 


1,145 


1,625 


3,471 


6,250 


9,853 


20,522 


36,308 


100 


147 


304 


619 


1,082 


1,535 


3,279 


5,903 


9,307 


19,385 


34,297 


125 


131 


270 


549 


959 


1,361 


2,906 


5,232 


8,249 


17,181 


30,396 


150 


118 


244 


497 


869 


1,233 


2,633 


4,741 


7,474 


15,567 


27,541 


175 


109 


225 


457 


799 


1,134 


2,423 


4,361 


6,876 


14,321 


25,338 


200 


101 


209 


426 


744 


1,055 


2,254 


4,057 


6,397 


13,323 


23,572 


225 


95 


196 


399 


698 


990 


2,115 


3,807 


6,002 


12,501 


22,117 


250 


90 


185 


377 


659 


935 


1,997 


3,596 


5,669 


11,808 


20,891 


275 


85 


176 


358 


626 


888 


1,897 


3,415 


5,385 


11,215 


19,841 


300 


81 


168 


342 


597 


847 


1,810 


3,258 


5,137 


10,699 


18,929 



' Table capacities are based on Type K copper tubing inside diameter (shown ) , which has the smallest inside diameter of the 
copper tubing products. 



2002 Edition 



54-82 



NATIONAL FUEL GAS CODE 



ANSI Z223. 1-82 



Table 12.26 Semi-Rigid Copper Tubing 








Gas 


Undiluted Propane 




Inlet pressure 


ILO in. w.c. 




Pressure Drop 


0.5 in. w.c. 




Specific Gravity 


1.50 


SPECIAL USE: 


Sizing Between Single or Second Stage (Low Pressure Regulator) and Appliance 



Tube Size (in.) 





K&L 


'/4 


■yg 


V2 


Vs 


y4 


1 


11/4 


l'/2 


2 


2V2 


Nominal 


ACR 


■Vs 


'/2 


5/8 


% 


Vs 


l>/8 


P/s 


P/s 


2'/s 


2Vs 


Outside 


0.375 


0.500 


0.625 


0.750 


0.875 


1.125 


1.375 


1.625 


2.125 


2.625 


Inside' 


0.305 


0.402 


0.527 


0.652 


0.745 


0.995 


1.245 


1.481 


1.959 


2.435 


Length 

(ft) 


Maximum Capacity in Thousands of Btu per Hour 


10 


45 


93 


188 


329 


467 


997 


1,795 


2,830 


5,895 


10,429 


20 


31 


64 


129 


226 


321 


685 


1,234 


1,945 


4,051 


7,168 


30 


25 


51 


104 


182 


258 


550 


991 


1,562 


3,253 


5,756 


40 


21 


44 


89 


155 


220 


471 


848 


1,337 


2,784 


4,926 


50 


19 


39 


79 


138 


195 


417 


752 


1,185 


2,468 


4,366 


60 


17 


35 


71 


125 


177 


378 


681 


1,074 


2,236 


3,956 


70 


16 


32 


66 


115 


163 


348 


626 


988 


2,057 


3,639 


80 


15 


30 


61 


107 


152 


324 


583 


919 


1,914 


3,386 


90 


14 


28 


57 


100 


142 


304 


547 


862 


1,796 


3,177 


100 


13 


27 


54 


95 


134 


287 


517 


814 


1,696 


3,001 


125 


11 


24 


48 


84 


119 


254 


458 


722 


1,503 


2,660 


150 


10 


21 


44 


76 


108 


230 


415 


654 


1,362 


2,410 


175 


10 


20 


40 


70 


99 


212 


382 


602 


1,253 


2,217 


200 


8.9 


18 


37 


65 


92 


197 


355 


560 


1,166 


2,062 


225 


8.3 


17 


35 


61 


87 


185 


333 


525 


1,094 


1,935 


250 


7.9 


16 


33 


58 


82 


175 


315 


496 


1,033 


1,828 


275 


7.5 


15 


31 


55 


78 


166 


299 


471 


981 


1,736 


300 


7.1 


15 


30 


52 


74 


158 


285 


449 


936 


1,656 



' Table capacities are based on Type K copper tubing inside diameter (shown), which has the smallest inside diameter of the 
copper tubing products. 



2002 Edition 



ANSI Z223. 1-83 



PIPE SIZING 



54-83 



Table 12.27 Semi-Rigid Copper Tubing 








Gas 


Undiluted Propane 




Inlet pressure 


2.0 psi 




Pressure Drop 


1.0 psi 




Speciflc Gravity 


1.50 



Tube Size (in.) 





K&L 


1/4 


% 


1/4 


5/8 


3/4 


1 


11/4 


11/2 


2 


2'A 


Nominal 


ACR 


Vs 


'/2 


5/8 


3/4 


% 


l'/8 


P/8 


iy8 


2 1/8 


2% 


Outside 


0.375 


0.500 


0.625 


0.750 


0.875 


1.125 


1.375 


1.625 


2.125 


2.625 


Inside' 


0.305 


0.402 


0.527 


0.652 


0.745 


0.995 


1.245 


1.481 


1.959 


2.435 


Length 

(ft) 








Maximum 


Capacity in Thousands of Btu per Hour 








10 


413 


852 


1,732 


3,027 


4,295 


9,175 


16,517 


26,042 


54,240 


95,962 


20 


284 


585 


1,191 


2,081 


2,952 


6,306 


11,352 


17,899 


37,279 


65,954 


30 


228 


470 


956 


1,671 


2,371 


5,064 


9,116 


14,373 


29,936 


52,963 


40 


195 


402 


818 


1,430 


2,029 


4,334 


7,802 


12,302 


25,621 


45,330 


50 


173 


356 


725 


1,267 


1,798 


3,841 


6,915 


10,903 


22,708 


40,175 


60 


157 


323 


657 


1,148 


1,629 


3,480 


6,266 


9,879 


20,575 


36,401 


70 


144 


297 


605 


1,057 


1,499 


3,202 


5,764 


9,088 


18,929 


33,489 


80 


134 


276 


562 


983 


1,394 


2,979 


5,363 


8,455 


17,609 


31,155 


90 


126 


259 


528 


922 


1,308 


2,795 


5,031 


7,933 


16,522 


29,232 


100 


119 


245 


498 


871 


1,236 


2,640 


4,753 


7,493 


15,607 


27,612 


125 


105 


217 


442 


772 


1,095 


2,340 


4,212 


6,641 


13,832 


24,472 


150 


95 


197 


400 


700 


992 


2,120 


3,817 


6,017 


12,533 


22,173 


175 


88 


181 


368 


644 


913 


1,950 


3,511 


5,536 


11,530 


20,399 


200 


82 


168 


343 


599 


849 


1,814 


3,267 


5,150 


10,727 


18,978 


225 


77 


158 


321 


562 


797 


1,702 


3,065 


4,832 


10,064 


17,806 


250 


72 


149 


304 


531 


753 


1,608 


2,895 


4,564 


9,507 


16,819 


275 


69 


142 


288 


504 


715 


1,527 


2,750 


4,335 


9,029 


15,974 


300 


66 


135 


275 


481 


682 


1,457 


2,623 


4,136 


8,614 


15,240 



1 Table capacities are based on Type K copper tubing inside diameter (shown), which has the smallest inside diameter of the 
copper tubing products. 



2002 Edition 



54-84 



NATIONAL FUEL GAS CODE 



ANSI Z223. 1-84 



Table 12.28 Corrugated Stainless Steel Tubing (CSST) 








Gas 


Undiluted Propane 




Inlet pressure 


ll.Oin. w.c. 




Pressure Drop 


0.5 in. w.c. 




Specific Gravity 


1.50 



Tube Size (EHD)« 



Flow 
Designation: 


13 


15 


18 


19 


23 


25 


30 


31 


37 


46 


62 


Length 

(ft) 


Maximum Capacity in Cubic Feet of Gas per Hour 


5 


72 


99 


181 


211 


355 


426 


744 


863 


1,415 


2,830 


6,547 


10 


50 


69 


129 


150 


254 


303 


521 


605 


971 


1,993 


4,638 


15 


39 


55 


104 


121 


208 


248 


422 


490 


775 


1,623 


3,791 


20 


34 


49 


91 


106 


183 


216 


365 


425 


661 


1,404 


3,285 


25 


30 


42 


82 


94 


164 


192 


325 


379 


583 


1,254 


2,940 


30 


28 


39 


74 


87 


151 


177 


297 


344 


528 


1,143 


2,684 


40 


23 


33 


64 


74 


131 


153 


256 


297 


449 


988 


2,327 


50 


20 


30 


58 


66 


118 


137 


227 


265 


397 


884 


2,082 


60 


19 


26 


53 


60 


107 


126 


207 


241 


359 


805 


1,902 


70 


17 


25 


49 


57 


99 


117 


191 


222 


330 


745 


1,761 


80 


15 


23 


45 


52 


94 


109 


178 


208 


307 


696 


1,647 


90 


15 


22 


44 


50 


90 


102 


169 


197 


286 


656 


1,554 


100 


14 


20 


41 


47 


85 


98 


159 


186 


270 


621 


1,475 


150 


11 


15 


31 


36 


66 


75 


123 


143 


217 


506 


1,205 


200 


9 


14 


28 


33 


60 


69 


112 


129 


183 


438 


1,045 


250 


8 


12 


25 


30 


53 


61 


99 


117 


163 


390 


934 


300 


8 


11 


23 


26 


50 


57 


90 


107 


147 


357 


854 



Note: Table includes losses for four 90-degree bends and two end fittings. Tubing runs with larger numbers of bends and/or 
fittings shall be increased by an equivalent length of tubing to the following equadon: L = 1 .3w, where L is additional length 
(ft) of tubing and n is the number of additional fittings and/or bends. 

*EHD = Equivalent Hydraulic Diameter, which is a measure of the relative hydraulic efficiency between different tubing 
sizes. The greater the value of EHD, the greater the gas capacity of the tubing. 



2002 Edition 



ANSI Z223.1-85 



PIPE SIZING 



54-85 



Table 12.29 Corrugated Stainless Steel Tubing (CSST) 



Gas 



Inlet pressure 



Pressure Drop 



Speciflc Gravity 



Undiluted Propane 



2.0 psi 



1.0 psi 



1.50 



Tube Size (EHD)* 



Flow 
Designation: 


13 


15 


18 


19 


23 


25 


30 


31 


37 


46 


62 


Length 

(ft) 


Maximum Capacity in Cubic Feet of Gas per Hour 


10 


426 


558 


927 


1,106 


1,735 


2,168 


4,097 


4.720 


7,128 


15,174 


34.203 


25 


262 


347 


591 


701 


1,120 


1,384 


2,560 


2,954 


4,564 


9,549 


21,680 


30 


238 


316 


540 


640 


1,027 


1,266 


2,331 


2,692 


4,176 


8,708 


19,801 


40 


203 


271 


469 


554 


896 


1,100 


2,012 


2,323 


3,631 


7,529 


17,159 


50 


181 


243 


420 


496 


806 


986 


1,794 


2,072 


3,258 


6,726 


15,357 


75 


147 


196 


344 


406 


663 


809 


1,457 


1,685 


2,675 


5,480 


12,551 


80 


140 


189 


333 


393 


643 


768 


1,410 


1,629 


2,591 


5,303 


12,154 


100 


124 


169 


298 


350 


578 


703 


1,256 


1,454 


2,325 


4,738 


10,877 


150 


101 


137 


245 


287 


477 


575 


1,021 


1,182 


1,908 


3,860 


8,890 


200 


86 


118 


213 


248 


415 


501 


880 


1,019 


1,658 


3,337 


7,705 


250 


77 


105 


191 


222 


373 


448 


785 


910 


1,487 


2,981 


6,895 


300 


69 


96 


173 


203 


343 


411 


716 


829 


1,363 


2,719 


6,296 


400 


60 


82 


151 


175 


298 


355 


616 


716 


1,163 


2,351 


5,457 


500 


53 


72 


135 


158 


268 


319 


550 


638 


1,027 


2,101 


4,883 



Notes: 

1. Table does not include eflFect of pressure drop across the line regulator. Where regulator loss exceeds Vi psi (based on 
13 in. w.c. outlet pressure), do not use this table. Consult with regulator manufacturer for pressure drops and capacity 
factors. Pressure drops across a regulator may vary with flow rate. 

2. CAUTION: Capacities shown in table may exceed maximum capacity for a selected regulator. Consult with regulator or 
tubing manufacturer for guidance. 

3. Table includes losses for four 90-degree bends and two end fitdngs. Tubing runs with larger number of bends and/or 
fitdngs shall be increased by an equivalent length of tubing according to the following equation: L = 1.3n, where L is 
additional length (ft) of tubing and n is the number of additional fittings and/or bends. 

*EHD = Equi\^ent Hydraulic Diameter, which is a measure of the relative hydraulic efificiency between different tubing 
sizes. The greater the value of EHD, the greater the gas capacity of the tubing. 



2002 Edition 



54-86 



NATIONAL FUEL GAS CODE 



ANSI Z223. 1-86 



Table 12.30 Corrugated Stainless Steel Tubing (CSST) 








Gas 


Undiluted Propane 




Inlet pressure 


5.0 psi 




Pressure Drop 


3.5 psi 




Specific Gravity 


1.50 



Tube Size (EHD)* 



Flow 
Designation: 


13 


15 


18 


19 


23 


25 


30 


31 


37 


46 


62 


Lengfth 

(ft) 








Maximum Capacity in Cubic Feet of Gas pet 


Hour 








10 


826 


1,065 


1,713 


2,061 


3,153 


3,999 


7,829 


8,945 


13,112 


28,580 


63,788 


25 


509 


664 


1,092 


1,307 


2,037 


2,554 


4,864 


5,600 


8,395 


17,986 


40,436 


30 


461 


603 


999 


1,193 


1,866 


2,336 


4,430 


5,102 


7,682 


16,403 


36,928 


40 


396 


520 


867 


1,033 


1,629 


2,029 


3,822 


4,404 


6,679 


14,183 


32,004 


50 


352 


463 


777 


926 


1,463 


1,819 


3,409 


3,929 


5,993 


12,670 


28,642 


75 


284 


376 


637 


757 


1,206 


1,492 


2,769 


3,194 


4,919 


10,322 


23,409 


80 


275 


363 


618 


731 


1,169 


1,446 


2,677 


3,090 


4,768 


9,990 


22,670 


100 


243 


324 


553 


656 


1,051 


1,296 


2,388 


2,756 


4,276 


8,925 


20,287 


150 


196 


262 


453 


535 


866 


1,062 


1,941 


2,241 


3,511 


7,271 


16,581 


200 


169 


226 


393 


464 


755 


923 


1,675 


1,934 


3,052 


6,287 


14,369 


250 


150 


202 


352 


415 


679 


828 


1,493 


1,726 


2,738 


5,616 


12,859 


300 


136 


183 


322 


379 


622 


757 


1,359 


1,572 


2,505 


5,122 


11,745 


400 


117 


158 


279 


328 


542 


657 


1,173 


1,356 


2,178 


4,429 


10,178 


500 


104 


140 


251 


294 


488 


589 


1,046 


1,210 


1,954 


3,957 


9,108 



Notes: 

1. Table does not include effect of pressure drop across line regulator. Where regulator loss exceeds 1 psi, do not use this 
table. Consult with regulator manufacturer for pressure drops and capacity factors. Pressure drop across regulator may vary 
with the flow rate. 

2. CAUTION: Capacities shown in table may exceed maximum capacity of selected regulator. Consult with tubing manufac- 
turer for guidance. 

3. Table includes losses for four 90-degree bends and two end fittings. Tubing runs with larger numbers of bends and/or 
fittings shall be increased by an equivalent length of tubing to the following equation: L = 1.3re, where L is additional length 
(ft) of tubing and n is the number of additional fitungs and/or bends. 

*EHD = Equivalent Hydraulic Diameter, which is a measure of the relative hydraulic efficiency between different tubing 
sizes. The greater the value of EHD, the greater the gas capacity of the tubing. 



2002 Edition 



ANSI Z223. 1-87 



PIPE SIZING 



54-87 



Table 12.31 Polyethylene Plastic Pipe 



Gas 



Inlet pressure 



Pressure Drop 



Specific Gravity 



Undiluted Propane 



11.0 in. w.c. 



0.5 in. w.c. 



1.50 



Pipe Size (in.) 



Nominal OD 


¥i 


% 


1 


11/4 


11/2 


2 


Designation: 


SDR 9.33 


SDR 11.0 


SDR 11.00 


SDR 10.00 


SDR 11.00 


SDR 11.00 


Actual ID 


0.660 


0.860 


1.077 


1.328 


1.554 


1.943 


Length 

(ft) 


Maximum Capacity in Thousands of Btu per Hour 


10 


340 


680 


1,227 


2,126 


3,211 


5,769 


20 


233 


467 


844 


1,461 


2,207 


3,965 


30 


187 


375 


677 


1,173 


1,772 


3,184 


40 


160 


321 


580 


1,004 


1,517 


2,725 


50 


142 


285 


514 


890 


1,344 


2,415 


60 


129 


258 


466 


807 


1,218 


2,188 


70 


119 


237 


428 


742 


1,121 


2,013 


80 


110 


221 


398 


690 


1,042 


1,873 


90 


103 


207 


374 


648 


978 


1,757 


100 


98 


196 


353 


612 


924 


1,660 


125 


87 


173 


313 


542 


819 


1,471 


150 


78 


157 


284 


491 


742 


1,333 


175 


72 


145 


261 


452 


683 


1,226 


200 


67 


135 


243 


420 


635 


1,141 



2002 Edition 



54-88 



NATIONAL FUEL GAS CODE 



ANSI Z223. 1-88 



Table 12.32 Polyethylene Plastic Pipe 



Gas 



Inlet pressure 



Pressure Drop 



Specific Gravity 



Undiluted Propane 



2.0 psi 



LOpsi 



1.50 



Pipe Size (in.) 



Nominal OD 


Vi 


% 


1 


l'/4 


\V2 


2 


Designation: 


SDR 9.33 


SDR 11.0 


SDR 11.00 


SDR 10.00 


SDR 11.00 


SDR 11.00 


Actual ID 


0.660 


0.860 


1.077 


1.328 


1.554 


1.943 


Length 

(ft) 


Maximum Capacity in Thousands of Btu per Hour 


10 


3,126 


6,259 


11,293 


19,564 


29,545 


53,085 


20 


2,148 


4,302 


7,762 


13,446 


20,306 


36,485 


30 


1,725 


3,454 


6,233 


10,798 


16,307 


29,299 


40 


1,477 


2,957 


5,335 


9,242 


13,956 


25,076 


50 


1,309 


2,620 


4,728 


8,191 


12,369 


22,225 


60 


1,186 


2,374 


4,284 


7,421 


11,207 


20,137 


70 


1,091 


2,184 


3,941 


6,828 


10,311 


18,526 


80 


1,015 


2,032 


3,666 


6,352 


9,592 


17,235 


90 


952 


1,907 


3,440 


5,960 


9,000 


16,171 




100 


899 


1,801 


3,249 


5,629 


8,501 


15,275 


125 


797 


1,596 


2,880 


4,989 


7,535 


13,538 


150 


722 


1,446 


2,609 


4,521 


6,827 


12,266 


175 


664 


1,331 


2.401 


4,159 


6,281 


11,285 


200 


618 


1,238 


2,233 


3,869 


5,843 


10,498 



2002 Edition 



ANSI Z223. 1-89 



SIZING OF CATEGORY I VENTING SYSTEMS 



54-89 



Table 12.33 Polyethylene Plastic Tubing 



Gas 



Inlet pressure 



Pressure Drop 



Specific Gravity 



Undiluted Propane 



11.0 in. w.c. 



0.5 in. w.c. 



1.50 



Plastic Tubing Size (GTS) (in.) 



Nominal OD 


¥z 


% 


Designation: 


SDR 7.00 


SDR 11.00 


Actual ID 


0.445 


0.927 


Length 

(ft) 


Maximum Capacity in Thousands of Btu per Hour 


10 


121 


828 


20 


83 


569 


30 


67 


457 


40 


57 


391 


50 


51 


347 


60 


46 


314 


70 


42 


289 


80 


39 


269 


90 


37 


252 


100 


35 


238 


125 


31 


211 


150 


28 


191 


175 


26 


176 


200 


24 


164 


225 


22 


154 


250 


21 


145 


275 


20 


138 


300 


19 


132 


350 


18 


121 


400 


16 


113 



Chapter 13 Sizing of Category I Venting Systems 

13.1 Additional Requirements to Single Appliance Vent 
Table 13.1 Through Table 13.5 

13.1.1 Obstructions and Vent Dampers. These venting tables 
shall not be used where obstructions (see Section 10.15) are 
installed in the venting system. The installation of vents serv- 
ing listed appliances with vent dampers shall be in accordance 
with the appliance manufacturer's instructions or in accor- 
dance with the follov«ng: 

(1) The maximum capacity of the vent system shall be deter- 
mined using the "NAT Max" column. 

(2) The minimum capacity shall be determined as if the ap- 
pliance were a fan-assisted appliance, using the "FAN 
Min" column to determine the minimum capacity of the 
vent system. Where the corresponding "Fan Min" is "NA," 



the vent configuration shall not be permitted and an al- 
ternative venting configuration shall be utilized. 

13.1.2 Vent Downsizing. Where the vent size determined 
from the tables is smaller than the appliance draft hood oudet 
or flue collar, the use of the smaller size shall be permitted 
provided that the installation complies with all of the follow- 
ing requirements: 

(1) The total vent height (H) is at least 10 ft (3 m). 

(2) Vents for appliance draft hood outlets or flue collars 12 in. 
(300 mm) in diameter or smaller are not reduced more 
than one table size. 

(3) Vents for appliance draft hood outlets or flue collars 
larger than 12 in. (300 mm) in diameter are not reduced 
more than two table sizes. 

(4) The maximum capacity listed in the tables for a fan- 
assisted appliance is reduced by 10 percent (0.90 x maxi- 
mum table capacity) . 

(5) The draft hood outlet is greater than 4 in. (100 mm) in 
diameter. Do not connect a 3-in. (80-mm) diameter vent 
to a 4-in. (100-mm) diameter draft hood outlet. This pro- 
vision shall not apply to fan-assisted appliances. 

13.1.3 Elbows. Single-appliance venting configurations with 
zero (0) lateral lengths in Table 13.1, Table 13.2, and Table 
13.5 shall not have elbows in the venting system. For vent con- 
figurations with lateral lengths, the venting tables include al- 
lowance for two 90 degree turns. For each elbow up to and 
including 45 degrees, the maximum capacity listed in the 
venting tables shall be reduced by 5 percent. For each elbow 
greater than 45 degrees up to and including 90 degrees, the 
maximum capacity listed in the venting tables shall be re- 
duced by 10 percent. 

13.1.4 Zero Lateral. Zero (0) lateral (L) shall apply only to a 
straight vertical vent attached to a top outlet draft hood or flue 
collar. 

13.1.5 High Altitude Installations. Sea level input ratings shall 
be used when determining maximum capacity for high- 
altitude installation. Actual input (derated for altitude) shall 
be used for determining minimum capacity for high-altitude 
installation. 

13.1.6 Two Stage /Modulating Appliances. For appliances 
with more than one input rate, the minimum vent capacity 
(FAN Min) determined from the tables shall be less than the 
lowest appliance input rating, and the maximum vent capacity 
(FAN Max/NAT Max) determined from the tables shall be 
greater than the highest appliance rating input. 

13.1.7* Corrugated Chimney Liners. Listed corrugated metal- 
lic chimney liner systems in masonry chimneys shall be sized 
by using Table 13.1 or Table 13.2 for Type B vents with the 
maximum capacity reduced by 20 percent (0.80 x maximum 
capacity) and the minimum capacity as shown in Table 13.1 or 
Table 13.2. Corrugated metallic liner systems installed with 
bends or ofisets shall have their maximum capacity further 
reduced in accordance with 13.1.3. The 20 percent reduction 
for corrugated metallic chimney liner systems includes an al- 
lowance for one long radius 90-degree turn at the bottom of 
the liner. 

13.1.8 Vertical Vent Upsizing/7x Rule. Where the vertical 
vent has a larger diameter than the vent connector, the verti- 
cal vent diameter shall be used to determine the minimum 
vent capacity, and the connector diameter shall be used to 
determine the maximum vent capacity. The flow area of the 
vertical vent shall not exceed seven times the flow area of the 
listed appliance categorized vent area, flue collar area, or draft 



2002 Edition 



54-90 



NATIONAL FUEL GAS CODE 



ANSI Z223. 1-90 



Table 13.1 


Type 


B Double-Wall Gas Vent 


















































Number of Appliances: 


Single 




Appliance Type: 


Category I 




Appliance Vent Connection: 


Connected Directly to Vent 




Lateral 
L 

(ft) 


Vent Diameter — D (in.) 




3 


4 


5 


6 


7 


8 


9 
















Appliance 


Input Rating 


in Thousands of Btu per Hour 














Height 


FAN 




-NAT . 


FAN \ 


NAT.. 
.Max<~ 


FAN \ 


NAT.'' 
Max-*- 


FAN ;'-'NXT; 


FAN f-NAT: 


FAN !. 


NAT;: 

Mas;:.. 


FAN f 


i<iM 


H 

(ft) 


Min Max 


Min 


Max i 


Min 


Max 1: 


Min 


Max !:Max;;; 


Min 


Max ."Max-. 


Min 


Max ; 


Min 


Max ) 


Mak; 


6 








78^ 


.46, 





152 ! 


■ ■M 





251 I 


■ j^ 





375 !;: -205: 





524 L;285, 





698 [ 


::370: 





897! 


470 




2 


13 


51 1 


36 


18 


97! 


67 


27 


157;, 


105 


32 


232 : 157 


44 


321 ■ 217 


53 


425 i 


285 


63 


543 ; 


370 




4 


21 


49 i 


■ ^.iM 


30 


94; 


.,;;.64. 


39 


153 ; 


.a()3 


50 


227 ; .153; 


66 


316 .';.;2I1=; 


79 


419 =; 


;.279, 


93 


536 :, 


362 




6 


25 


46 1 


32 


36 


91 ; 


61 


47 


149 j 


100 


59 


223 ; 149 


78 


310 i 205 


93 


413 I 


v^ 


110 


530 1 


354 


8 








84? 


50 





165 ; 


'94 





276; 


■ 155' 





415 '■ ^ 





583 r^20 





780 = 


'"'M~ 





1006 \ 


' 53^ 




2 


12 


57 - 


40. 


16 


109 i 


..-,;75„ 


25 


178 I 


.120. 


28 


263 !; ;,;180; 


42 


365 : .:247. 


50 


483 1, 


.= 322; 


60 


619 ; 


418 




5 


23 


53^ 


38 


32 


103; 


;7i 


42 


171 i 


115 


53 


255 i 173 


70 


356 \ 237 


83 


473 = 


313 


99 


607.^ 


407 




8 


28 


49; 


;;-.35. 


39 


98 


iW 


51 


164 \ 


- ap9j 


64 


247 ;; = 165? 


84 


347 ;f;.m: 


99 


463 !l 


'\'^- 


117 


596 ;; 


396 


10 








88 t 


53; 





175 [ 


.;io:o. 





295- 


;;166; 





447 ..,..255: 





631 L 345; 





847^ 


^ ; 450 





1096 1 


585 




2 


12 


61 ' 


42 


17 


118 ; 


81 


23 


194; 


129 


26 


289 ■: 195 


40 


402 I 273" 


48 


533 i 


355 


57 


684 1 


457 




5 


23 


57 


- .-.40 


32 


113 


^ u77 


41 


187 r 


-.124; 


52 


280 h.;188; 


68 


392 ;; ;263; 


81 


522 ii 


;:346; 


95 


671 I 


446 




10 


30 


51 \ 


36 


41 


104 \ 


-70 


54 


176; 


115 


67 


267 : 175 


88 


376 , 245 


104 


504 


330 


122 


651 1 


427 


15 








94 : 


' 58^ 





191 f 


■ ' ii.. ;■ 

112 





327 • 


' 187 





502 [' km 





716 = 390 





970 


'5^5:' 





1263 \ 


' 682 




2 


11 


69 I 


;.:;.48 


15 


136 , 


■m 


20 


226 = 


150 


22 


339 U;,225; 


38 


475 ;,,;316. 


45 


633 


.Jl4; 


53 


815 ; 


544 




5 


22 


65 : 


45 


30 


130 i 


'87 


39 


219 i 


142 


49 


330; 217 


64 


463 ; 300 


76 


620} 


403 


90 


800 [ 


52S 




10 


29 


59 


' ■:4I 


40 


121 . 


..:82 


51 


206 i 


. ;135.- 


64 


315 i; ;2Q8; 


84 


445 ;-;288 


99 


600 ;. 


f:386: 


116 


777 1 


: 507 




15 


35 


53; 


37 


48 


112 \ 


7,6 


61 


195 1 


128 


76 


301 198 


98 


429 ; 275 


115 


580 i 


373 


134 


755 1 


491= 


20 








97; 


'61 





202 1 


""'ii^' 





349 : 


262 





540 , 307 





776 f 430 





1057? 


'■-575^ 





1384 f 


752 




2 


10 


75: 


■■ .3X- 


14 


149 , 


;100 


18 


250 i 


, 166 


20 


377 i .;249. 


33 


531 ;.:,,346 


41 


711 ; 


:?47G. 


50 


917! 


612 




5 


21 


71 i 


48 


29 


143 i 


96 


38 


242 i 


160 


47 


367 ; 241 


62 


519 '■■■ 337 


73 


697^ 


460 


86 


902 1 


599 




10 


28 


64 


= .'--^ 


38 


133 ; 


. rm 


50 


229 r. 


!-:150- 


62 


351 : . 228 


81 


499 p;.321. 


95 


675* 


-/:443: 


112 


877 = 


= 576 




15 


34 


58 : 


40 


46 


124; 


m 


59 


217 1 


142 


73 


337 i 217 


94 


481 ' 308 


111 


654 ; 


427 


129 


853 ] 


557 




20 


48 


52 


■.o35- 


55 


116 \ 


-■ = 78-: 


69 


206; 


'^■W^ 


84 


322 r 206 


107 


464 1 1 295; 


125 


634 l 


•'4i0; 


145 


830; 


537i 


30 








100 ^ 


' .64 





213 ! 


.*^i28; 





374 - 


,.m- 





587 .u336. 





853 -..,.475: 





1173 \ 


■.,0)i 





1548 \ 


855 




2 


9 


81 .. 


56 


13 


166 i 


112 


14 


283 


■185 


18 


432 • 280 


27 


613 ; 394 


33 


826 1 


535 


42 


1072 \ 


7oo: 




5 


21 


Ill 


•■ ■■'54 


28 


160 i 


.108 


36 


275; 


..-1.76 


45 


421 ;.:,-273: 


58 


600 =-385. 


69 


811 \. 


.;524:; 


82 


1055 ;-: 


688 




10 


27 


70 1 


50 


37 


150 : 


102 


48 


262 I 


171 


59 


405: 261 


77 


580 ■ 371 


91 


788 i 


507 


107 


1028 = 


668 




15 


33 


64 \ 


; -NA- 


44 


141 ^ 


^ ;:96 


57 


249 \ 


-=163' 


70 


389 -249' 


90 


560 --357 


105 


765 ;■ 


490 


124 


1002 ; 


648 




20 


56 


58 ! 


NA 


53 


132 i 


90 


66 


237 ; 


154 


80 


374 j 237 


102 


542 ; 343 


119 


743 ( 


473 


139 


977 ; 


628 




30 


NA 


NA; 


- .NA- 


73 


113 ; 


;;-NA 


88 


214 i 


;,;na: 


104 


346 i;:. 21 9- 


131 


507 i= ;32i; 


149 


702 \ 


"444; 


171 


929 1 


- 594 


50 








101 ■ 


■67 





216 1 


134 





397 ; 


232: 





633 ^ ,3;63: 





932 1.518^ 





1297 1 


.708. 





1730 1 


. 952 




2 


8 


86; 


61 


11 


183 1 


122 


14 


320 j 


206 


15 


497 : 314 


22 


715 445 


26 


975 1 


615 


33 


1276 1 


813, 




5 


20 


82 • 


■;na; 


27 


177 ; 


119 


35 


312 [ 


,200 


43 


487 ; .-308; 


55 


702 '..;438 


65 


960 I* 


.;;605; 


77 


1259 ' 


798 




10 


26 


76 ; 


NA 


35 


168 ; 


114 


45 


299 : 


190 


56 


471 ; 298 


73 


681 426 


86 


935 \ 


589 


101 


1230 1 


773 




15 


59 


70 


-.-^.■NA. 


42 


158 ; 


..-NA- 


54 


287 ' 


■180 


66 


455.5.-288^ 


85 


662 :>; ,413: 


100 


911 = 


.'.5.72: 


117 


1203 r 


747 




20 


NA 


NA : 


NA 


50 


149 ; 


NA 


63 


275; 


169 


76 


440 ! 278 


97 


642 : 401 


113 


888 i 


556 


131 


1176 ! 


722 




30 


NA 


NA ■ 


;-.NA 


69 


131 1 


- --NA 


84 


250 ; 


NA= 


99 


410 r- = 259': 


123 


605 :?; 376 


141 


844 ;= 


-^2- 


161 


1125 j= 


670 


100 





NA 


NA- 


;r., NA- 





218 \ 


;.^NA; 





407' 


- NA,- 





665 !;: 400; 





997 h:=560j 





1411 ; 


;.^;770 





1908; 


1040 




2 


NA 


NA \ 


NA 


10 


194 ; 


NA 


12 


354 \ 


NA 


13 


566 1 375 


18 


831 ; 510 


21 


1155 1 


700- 


25 


1536 ; 


935 




5 


NA 


NAi 


'J-.NA 


26 


189; 


^:;na 


33 


347 ;- 


-.■: NA- 


40 


557 ;-- 369; 


52 


820 ;;^504r 


60 


1141 ■: 


- = '692; 


71 


1519 ; 


926 




10 


NA 


NA i 


.NA 


33 


182 \ 


NA 


43 


335 ! 


NA 


53 


542 : 361 


68 


801 \ 493 


80 


1118 i 


679 


94 


1492 i 


910 




15 


NA 


NA- 


-.-NA- 


40 


174; 


■ ■ =NA 


50 


321 , 


"'NA- 


62 


528 ,- 353; 


80 


782 ::-482^ 


93 


1095 1 


666- 


109 


1465 r 


895 




20 


NA 


NA \ 


NA 


47 


166 1 


NA 


59 


311 \ 


NA 


71 


513 i 344 


90 


763 : 471 


105 


1073 i 


653; 


122 


1438 1 


880 




30 


NA 


NA' 


-iik 


NA 


NAf 


' NA.* 


78 


290; 


^:-NX- 


92 


483 '"^NA^ 


115 


726 ;*:449 


131 


1029 f 


*'--627' 


149 


1387 ;- 


' 849 




50 


NA 


NA j 


NA 


NA 


NA; 


^NA 


NA 


NAj 


. NA 


147 


428 ! NA 


180 


651 ' 405 


197 


944 ;, 


..575, 


217 


1288 i 


787 



2002 Edition 



ANSI Z223. 1-91 



SIZING OF CATEGORY I VENTING SYSTEMS 



54-91 



Table 13.1 Continued 















Number of Appliances: 


Single 






Appliance Type: 


Category I 






Appliance 


Vent Connection: 


Connected Directly to Vent 












Vent Diameter - 


-Z)(in.) 












10 


12 


14 


16 


18 


20 


22 


24 




Appliance Input Rating in Thousands of Btu per Hour 


Height Lateral 
H L 

(ft) (ft) 


FAN fNAX: 


FAN -NAtV 


FAN -NAT; 


FAN ^NAli 


FAN InA*^ 


FAN JNAt 


FAN NAT 


FAN 


\ NAT 


Min Max ^Max; 


Min 


Max !,Max^ 


Min 


Max ;Max; 


Min 


Max HMaki 


Min 


Max iNfiJc: 


Min 


Max j'Ma^^ 


Min 


Max Maui 


Min 


Max 


i Max 


6 


01121 J'576; 





1645 -1850: 





2267 ;i;i70; 





2983 3530; 





3802 b96o;; 





4721 12430; 





5737 2950 





6853 


13520 


2 


75 675 : 455: 


103 


982 "' 650'; 


138 


1346 '•': 890; 


178 


1769 ;ii7& 


225 


2250 .1480: 


296 


2782 : 1850 


360 


3377 2220 


426 


4030 


2670 


4 


110 668 >:r;4^5; 


147 


975 :;640; 


191 


1338 ; 88d; 


242 


1761 [1160; 


300 


2242 ;1475- 


390 


2774 a835; 


469 


3370 2215 


555 


4023 


1 2660 


6 


128 661 r;435: 


171 


967 p 63& 


219 


1330 ; 870, 


276 


1753 ;ii5q: 


341 


2235 [ 1470; 


437 


2767 il820 


523 


3363 2210 


618 


4017 


; 2650 


8 


1261 :!-666^' 





1858 J?97i0? 





2571 'l'32'O^ 





3399 !ii-74o; 





4333 ;22S!d; 





5387 r275d- 





6555 3360 





7838 


■4010 


2 


71 770 t ^515- 


98 


1124 ■745;; 


130 


1543 ,1020 


168 


2030 £1340'; 


212 


2584 i 1700-: 


278 


3196 !2li0 


336 


3882 2560 


401 


4634 


: 3050 


5 


115 758 ;i503; 


154 


1110 ■'-733 


199 


1528 -iOltf, 


251 


2013 ?ii330- 


311 


2563 Fl'685; 


398 


3180 r2090- 


476 


3863 2545 


562 


4612 


;3040 


8 


137 746 ;; 490; 


180 


1097 720'; 


231 


1514 lOOQl 


289 


2000 ia320; 


354 


2552 ; 1670; 


450 


3163 12070 


537 


3850 2530 


630 


4602 


: 3030 


10 


1377 H:72G' 





2036 S'lO^O* 





2825 H'm- 





3742 !t92§; 





4782 >245(¥ 





5955 13050 





7254 3710 





8682 


' 4450 


2 


68 852 ;v;56a; 


93 


1244 : 850 


124 


1713 rI130T 


161 


2256 ;1480: 


202 


2868 USgO- 


264 


3556 ;,234d> 


319 


4322 2840 


378 


5153 


. 3390 


5 


112 839 :■ 547; 


149 


1229 8^9 


192 


1696 11105: 


243 


2238 11461; 


300 


2849 ; 187f 


382 


3536 :2318 


458 


4301 2818 


540 


5132 


3371 


10 


142 817 ph^?5; 


187 


1204 1 795; 


238 


1669 ;l()8a- 


298 


2209 jMSO: 


364 


2818 fl84(); 


459 


3504 i228a 


546 


4268 2780 


641 


5099 


;3340 


15 


1596 ! 840; 





2380 ii24(j:; 





3323 [1720: 





4423 12270: 





5678 :2900:; 





7099 ;3620 





8665 4410 





10,393 


\ 5300 


2 


63 1019 r; 675t 


86 


1495 r 985' 


114 


2062 ^1350; 


147 


2719 ;;r77(); 


186 


3467 ;^26d; 


239 


4304 l28dd 


290 


5232 3410 


346 


6251 


1 4080 


5 


105 1003 : ; 660" 


140 


1476 ' 967; 


182 


2041 ;1327- 


229 


2696 ri^48; 


283 


3442 12235? 


355 


4278 -2777 


426 


5204 3385 


501 


6222 


i 4057 


10 


135 977 in 6351 


177 


1446 1 -936; 


227 


2009 11289- 


283 


2659 Ilj712i 


346 


3402 ;2193: 


432 


4234 ;..2739:. 


510 


5159 .3343 


599 


6175 


4019 


15 


155 953 ; 610 


202 


1418 \ 905 


257 


1976 1250, 


318 


2623 ;:i675; 


385 


3363 ; 215QV 


479 


4192 ;27dd 


564 


5115 3300 


665 


6129 


3980 


20 


1756?^io^ 





2637 .-1350; 





3701 aQoo; 





4948 p2520? 





6376 !3^d= 





7988 [4060 





9785 4980 


11,753 


6000 


2 


59 1 150 '-■. 7551. 


81 


1694 iiioo; 


107 


2343 .1520; 


139 


3097 ■;2000; 


175 


3955 i 257U 


220 


4916 ^3200 


269 


5983 3910 


321 


7154 


i 4700 


5 


101 1133 >'738j 


135 


1674 ilO^I 


174 


2320 ^498; 


219 


3071 ;;f978: 


270 


3926 2544: 


337 


4885 r3l74 


403 


5950 3880 


475 


7119 


! 4662 


10 


130 1105 ■-■ 710 : 


172 


1641 J045i 


220 


2282 .-1460 


273 


3029 tl940; 


334 


3880 :2500- 


413 


4835 13130 


489 


5896 3830 


573 


7063 


i 4600 


15 


150 1078 V0k. 


195 


1609 ^ioi8: 


248 


2245 ;i4'25^ 


306 


2988 ^1910^; 


372 


3835 S^eSr 


459 


4786 13090= 


541 


5844 =3795 


631 


7007 


: 4575 


20 


167 1052 T; 665-; 


217 


1578 ; 99^ 


273 


2210 El390 


335 


2948 ^80^ 


404 


3791 ;.2430i 


495 


4737 13050 


585 


5792 3760 


689 


6953 


. 4550 


30 


1977 ;1066;' 





3004! 1556^ 





4252 '217Q- 





5725 j:'292d; 





7420 53770! 





9341 i4750 





11,483 5850 





13,848 


i 7060 


2 


54 1351 p'865] 


74 


2004 ;a3i^: 


98 


2786 ;1806i 


127 


3696 ;?38Qi 


159 


4734 ';305'd?: 


199 


5900 ;38id 


241 


7194 .;465.a 


285 


8617 


; 5600 


5 


961332 ^851'- 


127 


1981 rl'289; 


164 


2759 i775: 


206 


3666 ;::235d = 


252 


4701 ;3d2di 


312 


5863 ^3783 


373 


7155 4622 


439 


8574 


5552 


10 


125 1301 5:i829; 


164 


1944 11254; 


209 


2716 S1733; 


259 


3617 1 230.0: 


316 


4647 :^97d^ 


386 


5803 ;3739;, 


456 


7090 .4574 


535 


8505 


1 5471 


15 


143 1272 ;= i^d7^: 


187 


1908 !122'0i 


237 


2674 ;i*692l 


292 


3570 [2256' 


354 


4594 -^^20: 


431 


5744 13695 


507 


7026 4527 


590 


8437 


5391 


20 


160 1243 :-;784 


207 


1873 ' 1;185:^ 


260 


2633 ?i65(fc 


319 


3523 ;2200. 


384 


4542 ■;287d; 


467 


5686 ;3650 


548 


6964 4480 


639 


8370 


■ 5310 


30 


195 1 189 :i:745' 

Si- 


246 


1807 ;,ii3o: 


305 


2555 fisfe 


369 


3433 r2130 


440 


4442 ;^785.^ 


540 


5574 |3565 


635 


6842 4375 


739 


8239 


.5225 


50 


2231 5II95/; 





3441 \i825' 





4934 J^550i 





6711 f344d' 





8774 l44dd' 





11,129 |5635 





13,767 6940 





16,694 


8430 


2 


41 1620 ;'1010" 


66 


2431 rl51# 


86 


3409 '2i2R 


113 


4554 .2840 


141 


5864 ;%67Ql 


171 


7339 ;4630 


209 


8980 5695 


251 


10,788 


6860 


5 


90 1600 s;;996; 


118 


2406 !l495; 


151 


3380 ^-2102; 


191 


4520 E28I3-; 


234 


5826 13639; 


283 


7295 :4597f 


336 


8933 5654. 


394 10,737 


i 6818 


10 


118 1567 j 972i 


154 


2366 1:1466,: 


196 


3332 -2064 


243 


4464ft2767- 


295 


5763 f'3585- 


355 


7224 J4542 


419 


8855 5585 


491 


10,652 


: 6749 


15 


136 1536 :':948, 


177 


2327 [,143.7' 


222 


3285 ;2026^ 


274 


4409 ;272i; 


330 


5701 I353I; 


396 


7155 14511; 


465 


8779 5546 


542 


10,570 


■ 6710 


20 


151 1505 r 924- 


195 


2288 i 1408; 


244 


3239 a987: 


300 


4356 :2675' 


361 


5641 ;3481-- 


433 


7086 :4479 


506 


8704 5506 


586 


10,488 


6670 


30 


183 1446 ^; ;87fi; 


232 


2214 J1349; 


287 


3150 ;,191P: 


347 


4253 ^2631: 


412 


5523 i343i; 


494 


6953 ;44?:1;: 


577 


8557 5444 


672 10,328 


6603 


100 


2491 liSlCn 





3925 '205C 





5729:2950. 





7914 f.4050. 





10,485 i 5300; 





13,454 !670'0 





16,817 8600 





20,578 


10,300 


2 


30 1975 11170; 


44 


3027 ji820; 


72 


4313 ;255b: 


95 


5834 !350d; 


120 


7591 4600- 


138 


9577 ; 5800 


169 


11,803 7200 


204 


14,264 


8800 


5 


82 1955 fll59: 


107 


3002 f 1803 ; 


136 


4282 ; 2531; 


172 


5797 ;'3475' 


208 


7548 i 4566; 


245 


9528 ;5769 


293 


11,748 7162 


341 


14,204 


8756 


10 


108 1923 ;;i:142; 


142 


2961 'V1775J 


180 


4231 .^SOO; 


223 


5737 ;^434; 


268 


7478 ;4509;' 


318 


9447 '::57I7; 


374 


11,658 ;7100 


436 


14,105 


8683 


15 


126 1892 IllM 


163 


2920 i i747^ 


206 


4182 2469 


252 


5678 J 3392: 


304 


7409 ;4451; 


358 


9367 ; 5665 


418 


11,569 7037 


487 


14,007 


8610 


20 


141 1861 iiap7; 


181 


2880 ia7lS;; 


226 


4133 =2438 


277 


5619 '%351; 


330 


7341 |4394^ 


387 


9289 ;5613 


452 


11,482:6975 


523 


13,910 


8537 


30 


170 1802 'io7k 


215 


2803 ; 1663 


265 


4037 'Mi^: 


319 


5505 r'3'26'7 


378 


7209 \ 421^:; 


446 


9136 ; 5509 


514 


11,310 6850 


592 


13,720 


8391 


50 


241 1688 ?:1000:- 


292 


2657 ;a55Q; 


350 


3856 2250; 


415 


5289 i3.ldd: 


486 


6956 i;4p.50'. 


572 


8841 |53pp. 


659 


10,979 6600 


752 


13,354 


8100 



For SI units, 1 in. = 254 mm, 1 ft = 0.305 m, 1000 Btu/hr = 0.293 kW, 1 in.^ = 645 mm'-^. 



2002 Edition 



54-92 



NATIONAL FUEL GAS CODE 



ANSI Z223. 1-92 



Table 13.2 


Typ 


e B Double-WaU Vent 


















































Number of Appliances: 


Single 




Appliance Type: 


Category I 




Appliance Vent Connection: 


Single Wall Metal Connector 




Lateral 
L 

(ft) 


Vent Diameter — D (in.) 




3 


4 


5 


6 


7 


8 


9 


10 


12 














Appliance Input Rating 


in Thousands of Btu per Hour 








Height 


FAN I 




FAN ?NAT^ 


FAN > 


Vfax; 


FAN ^NATJ 


FAN 


SAT- 


FAN 


I^AT- 


FAN I 


^ATt 
MEaK= 


FAN NAT: 


FAN I^NAT^ 


H 

(ft) 


Min 


Max 


Min Max j Max 


Min 


Max 


Min Max jMax; 


Min 


Max 


Min Max 


Min 


Max 


?■:-■■ 

Min Max Max; 


Min 


] ■ i 
Max \ Max; 


6 





38 


77 


'^45; 


59 


151 I|k85. 


85 


249 !]40 


126 


373 ':204; 


165 


522 


1284 


211 695 


369 


267 


894 


4693: 


371 1118 \m- 


537 


1639 ; ,849| 




2 


39 


51 


i'm 


60 


96 ?;-66" 


85 


156 f^4r 


123 


231 i;i5fe 


159 


320 


ji2l3 


201 423 


■284 


251 


541 


368;i 


347 673 ;453' 


498 


979 f ;648| 




4 


NA 


NA 


^'■33 = 


74 


92 ;">f63 


102 


152 1102 


146 


225 i 152^^ 


187 


313 


1208 


237 416 


.277. 


295 


533 


360{ 


409 664 J443 


584 


971 638! 




6 


NA 


NA 


:;3P 


83 


89 .;v60^ 


114 


147 |:{99 


163 


220 "iX^m 


207 


307 


F203, 


263 409 


r271" 


327 


526 


^352; 


449 656 ifeS 


638 


962 \ ■:627 


8 





37 


83 


..m 


58 


164 t:;;93..: 


83 


273 154. 


123 


412 ^23*; 


161 


580 


;3i9v 


206 777 


^.414 .■ 


258 


1002 


53^; 


360 1257 ;i55S; 


521 


1852 i,:.967; 




2 


39 


56 


?39 


59 


108 i:-F75 ■ 


83 


176 119 


121 


261 rl79"; 


155 


363 


[246 


197 482 


321 


246 


617 


41 7-: 


339 768 1513 


486 


1120 i 7431 




5 


NA 


NA 


:;37-. 


77 


102 nl69. 


107 


168 '114; 


151 


252 vYJli 


193 


352 


1235 


245 470 


:311v. 


305 


604 


f«)4; 


418 754 i5p0; 


598 


1104 U;730i 
1089 ' 7l5i 




8 


NA 


NA 


.?3J; 


90 


95 k;64' 


122 


161 1107 


175 


243 [*i63? 


223 


342 


1-225 


280 458 


300 


344 


591 


392:; 


470 740 J486= 


665 


10 





37 


87 


?;;:■ ■■■■: 

--;53" 


57 


174 ;'::99-; 


82 


293 ii65; 


120 


444 H;254^ 


158 


628 


i^& 


202 844 f'^ 


253 


1093 


Wk 


351 1373i;7i8 


507 


2031 ^-li057i 




2 


39 


61 


•■ 41 


59 


117 ; g^O, 


82 


193 |128 


119 


287 [■194- 


153 


400 !272 


193 531 I 354 


242 


681 


456: 


332 849 ;559 


475 


1242 ■ 848; 




5 


52 


56 


.■139^ 


76 


111 i;'.76*- 


105 


185 il22; 


148 


277 lm>' 


190 


388 


!;261; 


241 518 f2M''- 


299 


667 


■44*: 


409 834 544: 


584 


1224 r;825 




10 


NA 


NA 


:;3^: 


97 


100 1^: 68 


132 


171 jll2 


188 


261 1 171] 


237 


369 


1241 


296 497 |^^5 


363 


643 


423: 


492 808 :.520 


688 


1194 ' .7881 


15 





36 


93 


y-^- 


56 


190 gar 


80 


325 W> 


116 


499 f-283^ 


153 


713 


i^^8'' 


195 966 1^5^3" 


244 


1259 


68ij 


336 1591 ;;838,; 


488 


2374 i ii37i 




2 


38 


69 


•::47, 


57 


136 l:im , 


80 


225 149 


115 


337': 221; 


148 


473 


i314 


187 631 ■ 413, 


232 


812 


543^. 


319 1015 -673; 


457 


1491 i 983| 




5 


51 


63 


=;44'- 


75 


128i;5=86: 


102 


216 1140' 


144 


326 f "2i'7r; 


182 


459 


^298 


231 616 ' 4fl<3 : 


287 


795 


■526:^ 


392 997 J657' 


562 


1469 ; '^631 




10 


NA 


NA 


•:.39 


95 


116 ;r;79 


128 


201 'i3r 


182 


308 ! 203- 


228 


438 


■284 


284 592L381 


349 


768 


501: 


470 966 .1628: 


664 


1433 1 928! 




15 


NA 


NA 


,iNAJ 


NA 


NA :B;^2- 


158 


186 :124 


220 


290 f\M^- 


272 


418 


i269 


334 568 r367 


404 


742 


48f 


540 937 ;:60f 


750 


1399 1 894j 


20 





35 


96 


~']M. 


54 


200 ^18 : 


78 


346 20i:- 


114 


537 |;306; 


149 


772 


&28: 


190 1053 ;i573;: 


238 


1379 


-750; 


326 1751 ^927; 


473 


2631 ) .1346; 




2 


37 


74 


".'50 


56 


148 ?*v-99 


78 


248 


165 


113 


375 1 248: 


144 


528 


f3*44 


182 708 > 468 


227 


914 1611- 


309 1146 [^754 


443 


1689 1 10981 




5 


50 


68 


~m 


73 


140 5:^:94; ; 


100 


239 


158/ 


141 


363 ?;239i- 


178 


514 


i334.. 


224 692 ii?157; 


279 


896 


1596" 


381 1126 ^734; 


547 


1665 i 107* 




10 


NA 


NA 


:■ AY 


93 


129 %m ' 


125 


223 


146 


177 


344 r'224; 


222 


491 


\m> 


277 666^437 


339 


866 


570: 


457 1092 t702; 


646 


1626 ! 1037! 




15 


NA 


NA 


sNA^ 


NA 


NA •,;;,8p: 


155 


208 !;136: 


216 


325 i210;: 


264 


469 


;3oi. 


325 640 f|419^ 


393 


838 


S549; 


526 1060 r.677; 


730 


1587 1,10051 




20 


NA 


NA 


JlNlAJ 


NA 


NA ;;;na 


186 


192 iisie 


254 


306 196: 


309 


448 


p5' 


374 616 ; 400- 


448 


810 


526;; 


592 1028 [651 


808 


1550 1 9731 


30 





34 


99 


ii63- 


53 


211 M^'"^ 


76 


372 l^lS- 


110 


584 ;33$^ 


144 


849 


r472.' 


184 1168 '^fW' 


229 


1542 


852 i 


312 1971 i;056 


454 


2996 ; ISfei 




2 


37 


80 


; 56 


55 


164 pill 


76 


281 ll83 


109 


429 [279' 


139 


610 


;392 


175 823 ; 533 


219 


1069 


698; 


296 1346 t863: 


424 


1999 1 1"308| 




5 


49 


74 


i^52; 


72 


157 •:106'; 


98 


271 \m^ 


136 


417 [.f271- 


171 


595 


382; 


215 806 r.521 ; 


269 


1049 


"684; 


366 1324 ;;846; 


524 


1971 ;-i283! 




10 


NA 


NA 


•NA 


91 


144 ':,-^98 


122 


255 1,168 


171 


397 1 257; 


213 


570 


i367 


265 777 ( 50i 


327 


1017 


662;; 


440 1287 !:82l 


620 


1927 ! 1243 




15 


NA 


NA 


'NA- 


115 


131 i^'^NA- 


151 


239 ;157 


208 


377 f;242* 


255 


547 


■349. 


312 750 : 481 


379 


985 


638! 


507 1251 r794 


702 


1884 ; 1205; 




20 


NA 


NA 


;NA 


NA 


NA >rNA 


181 


223 :na 


246 


357 [228- 


298 


524 


S333 


360 723 ; 461 


433 


955 


615" 


570 1216 i^68 


780 


1841 : 11661 




30 


NA 


NA 


f'NA 


NA 


NA g^NA; 


NA 


NA l,NA 


NA 


NA t.!NA: 


389 


477 


|305, 


461 670 fc:A26- 


541 


895 


574; 


704 1147 i720: 


937 


1759 U;i01= 


50 





33 


99 


L66- 


51 


213 Vl33 


73 


394 1230 


105 


629 1361;, 


138 


928 


^515 


176 1292 


70.4 


220 


1724 


948; 


295 2223 ivi89: 


428 


3432 , 18181 




2 


36 


84 


i-6i' 


53 


181 :;i2^ 


73 


318 ;^' 


104 


495 ;;3i2*T 


133 


712 


•443 


168 971 


•613' 


209 


1273 


811; 


280 1615 lti07' 


401 


2426 ; i569i 




5 


48 


80 


?NA 


70 


174 ':117 


94 


308 |19a 


131 


482 305: 


164 


696 


i435 


204 953 


602 


257 


1252 


795 


347 1591 *;*991 


496 


2396 ■ 1490 




10 


NA 


NA 


'^k 


89 


160 ::;:NA 


118 


292 rl-86 


162 


461 i'292;; 


203 


671 


r420 


253 923 


^583; 


313 


1217 


'765; 


418 1551 \^m 


589 


2347 1 1455 




15 


NA 


NA 


'INA 


112 


148 .'NA 


145 


275 jm 


199 


441 2807 


244 


646 


i405 


299 894 1 562 


363 


1183 


736 


481 1512 '934 


668 


2299 i 1421 1 




20 


NA 


NA 


::NA- 


NA 


NA JrNA 


176 


257 I-nX; 


236 


420 -.267; 


285 


622 


■■389 


345 866 ^543: 


415 


1150 


708: 


544 1473 :,906< 


741 


2251 i 13871 




30 


NA 


NA 


£NA' 


NA 


NA -rm 


NA 


NA InA 


315 


376 f. NA; 


373 


573 


[NA 


442 809 1 502 


521 


1086 


649- 


674 1399 f848 


892 


2159 ; 13181 


100 





NA 


NA 


IM 


49 


214 'Ma 


69 


403 INA 


100 


659 '^Ml 


131 


991 


1555 


166 1404 r 765' 


207 


1900 1033. 


273 2479 iiob- 


395 


3912 ^2642 




2 


NA 


NA 


^NA- 


51 


192 • ;NA 


70 


351 iNA 


98 


563 f:373- 


125 


828 


p508. 


158 1152 i 698, 


196 


1532 


,933r 


259 1970 1168 


371 


3021 1,1817 




5 


NA 


NA 


Ina: 


67 


186 :ina:' 


90 


342 fNA^ 


125 


551 ^^66- 


156 


813 


|501 


194 1134 [ W; 


240 


1511 


'921: 


322 1945 1=153" 


460 


2990 i 1^96 




10 


NA 


NA 


llslA^ 


85 


175 jc;nA 


113 


324 NA 


153 


532 \ 354, 


191 


789 


1:486 


238 1104 J 672 


293 


1477 


902.; 


389 1905 1=133 


547 


2938 ; 1763 




15 


NA 


NA 


iNA 


132 


162 t^K' 


138 


310 ^NA 


188 


511 y^[ 


230 


764 


f473^ 


281 1075 ?^6" 


342 


1443 


i"884; 


447 1865 1110 


618 


2888 1 1730 




20 


NA 


NA 


=^A 


NA 


NA j.-NA 


168 


295 iNA 


224 


487 i NA- 


270 


739 


1458 


325 1046! 639 


391 


1410 


!864: 


507 1825 1087 


690 


2838 ! 16% 




30 


NA 


NA 


fHk, 


NA 


NA KlNlA. 


231 


264 rNA^ 


301 


448 V^kt 


355 


685 


t'NA 


418 988 TNA 


491 


1343 


1824; 


631 1747 10411 


834 


2739 ! 1627 




50 


NA 


NA 


^NA' 


NA 


NA ijNA 


NA 


NA JNA 


NA 


NA i- NA- 


540 


584 


iNA 


617 866 [,NA 


711 


1205 


NA- 


895 1591 fNA 


138 


2547 j 1489 



For SI units, 1 in. = 254 mm, 1 ft = 0.305 m, 1000 Btu/hr = 0.293 kW, 1 in.^ = 645 mm'^. 



2002 Edition 



ANSI Z223. 1-93 



SIZING OF CATEGORY I VENTING SYSTEMS 



54-93 



Table 13.3 Masonry Chimney 








Number of Appliances: 


Single 




Appliance Type: 


Category 1 




Appliance Vent Connection: 


Type B Double Wall Connector 



Type B Double-Wall Connector Diameter — D (in.) 
To be used with chimney areas within the size limits at bottom 





3 


4 


5 


6 


7 


8 


9 


10 


12 
















Appliance Input Rating 


in Thousands of Btu per Hour 










Height Lateral 
H L 

(ft) (ft) 


FAN 1 




FAN T 


■^AT;- 
Nlax^ 


fan 1 


NJAT*; 

Max', 


FAN NAT' 


FAN 


MAT 
Max 


FAN iNAT' 


FAN 


NAT 
Max 


FAN 


NAT 
Max 


FAN InAT 


Min 


Max 


Min 


Max 


Min 


Max 


Min 


Max Max 


Min Max 


Min 


Max ^rMit;- 


Min Max 


Min Max 


Min 


Max ; Max 


6 2 


NA 


NA 


''W 


NA 


NA 


.r-52- 


NA 


NA 


""86- 


NA 


NA -isO^ 


NA 


NA 


'ISO 


NA 


NA ^\Wl 


NA 


NA 


320 


NA NA 


401 


NA 


NA i 581 


5 


NA 


NA 


}i?^> 


NA 


NA 


^49; 


NA 


NA 


;;82*- 


NA 


NA ^tH^ 


NA 


NA 


165 


NA 


NA ^{^t: 


NA 


NA 


; 298 


NA NA 


376 


NA 


NA ; 561 


8 2 


NA 


NA 


-29: 


NA 


NA 


^^55;: 


NA 


NA 


; 93 


NA 


NA ! .145 


NA 


NA 


,198 


NA 


NA ;i^266^ 


84 


590 


350 


100 728 


446 


139 


1024 ; 651 


5 


NA 


NA 


■26 


NA 


NA 


*'52 


NA 


NA 


' 88 


NA 


NA '■ 134 


NA 


NA 


183 


NA 


NA :;-=247' 


NA 


NA 


' 328 


149 711 


423 


201 


1007 '■ 640 


8 


NA 


NA 


'•^: 


NA 


NA 


,.:48. 


NA 


NA 


;. 83; 


NA 


NA |;127- 


NA 


NA 


1;75. 


NA 


NA H239J- 


NA 


NA 


H^^ 


173 695 


,410 


231 


990 1 623 


10 2 


NA 


NA 


:^:31: 


NA 


NA 


-:«!' 


NA 


NA 


U03: 


NA 


NA -162^ 


NA 


NA 


221 


68 


519 l!;298;- 


82 


655 


.388, 


98 810 


491 


136 


1144 ; 724 


5 


NA 


NA 


; 28 


NA 


NA 


-57 


NA 


NA 


96. 


NA 


NA M8 


NA 


NA 


204 


NA 


NA ^277 


124 


638 


365 


146 791 


466 


196 


1124 ' 712 


10 


NA 


NA 


:m 


NA 


NA 


;J50: 


NA 


NA 


;;;87- 


NA 


NA im 


NA 


NA 


191 


NA 


NA t263: 


155 


610 


347 


182 762 


444 


240 


1093 , 668 


15 2 


NA 


NA 


i'^l 


NA 


NA 


-'67: 


NA 


NA 


11* 


NA 


NA -1^9- 


53 


475 


;250- 


64 


613 ?; 336': 


77 


779 


441 


92 968 


562 


127 


1376 ' 841 


5 


NA 


NA 


;35 


NA 


NA 


';62 


NA 


NA 


107 


NA 


NA 1 164. 


NA 


NA 


231 


99 


594 ^,313. 


118 


759 


416 


139 946 


533 


186 


1352 828 


10 


NA 


NA 


-;28: 


NA 


NA 


.-55: 


NA 


NA 


"'97 


NA 


naJibb; 


NA 


NA 


21-6' 


126 


565 ;;;29& 


148 


727 


394 


173 912 


567 


229 


1315 i 777 


15 


NA 


NA 


■¥A. 


NA 


NA 


-;48. 


NA 


NA 


89; 


NA 


NA i I41.' 


NA 


NA 


201 


NA 


NA ^^281:^ 


171 


698 


375 


198 880 


485 


259 


1280 i 742; 


20 2 


NA 


NA 


.38 


NA 


NA 


:'74 


NA 


NA 


124* 


NA 


NA : 201 


51 


522 


274 


61 


678 i|375-.' 


73 


867 


491 


87 1083 


627 


121 


1548 i 953 


5 


NA 


NA 


:':36' 


NA 


NA 


*.68' 


NA 


NA 


ik; 


NA 


NA 184- 


80 


503 


254 


95 


658 i-^5b- 


113 


845 


463 


133 1059 


597 


179 


1523 " 933 


10 


NA 


NA 


iNA, 


NA 


NA 


;^6Q, 


NA 


NA 


a 07: 


NA 


NA:172; 


NA 


NA 


.237 


122 


627 :',332; 


143 


811 


440 


167 1022 


566 


221 


1482 ; 879 


15 


NA 


NA 


NA 


NA 


NA 


NA 


NA 


NA 


97 


NA 


NA ^ 159 


NA 


NA 


220 


NA 


NA i::3i4' 


165 


780 


418 


191 987 


541 


251 


1443 ; 840 


20 


NA 


NA 


:nA"; 


NA 


NA 


^NAi 


NA 


NA 


<^ 


NA 


NA jl48; 


NA 


NA 


:2p6 


NA 


NA ':]0&;- 


186 


750 


397 


214 955 


.513 


277 


1406 1 807 


30 2 


NA 


NA 


vM 


NA 


NA 


im^ 


NA 


NA 


=137; 


NA 


NA [2I6I 

f ; :,i-- 


47 


581 


303, 


57 


762 =;^2i; 


68 


985 


i .558 


81 1240 


•l717 


111 


1793 !1112 


5 


NA 


NAijNA^ 


NA 


NA 


im 


NA 


NA 


!128^ 


NA 


NA |198: 


75 


561 


■281 


90 


741 pl393; 


106 


962 


'526 


125 1216 


683 


169 


1766 i 1094 

i 


10 


NA 


NA 


:M- 


NA 


NA 


:n67 


NA 


NA 


-1151 


NA 


NA j-l&; 


NA 


NA 


*2'63 


115 


709 ;n373- 


135 


927 


500 


158 1176 


'^648 


210 


1721 il025 


15 


NA 


NA 


-'NA- 


NA 


NA 


■NA- 


NA 


NA 


107 


NA 


NA J M' 


NA 


NA 


243 


NA 


NA 'l:^il 


156 


893 


'476 


181 1139 


'621 


239 


1679 i 981! 


20 


NA 


NA 


,NA. 


NA 


NA 


iNA. 


NA 


NA 


. 91- 


NA 


NA i 159, 


NA 


NA 


.227 


NA 


NA !;;332; 


176 


860 


450 


203 1103 


.592 


264 


1638 ! 940 


30 


NA 


NA 


NA 


NA 


NA 


;:na= 


NA 


NA 


NA 


NA 


NA j'NA 


NA 


NA 


188 


NA 


NA r;'288' 


NA 


NA 


416 


249 1035 


555 


318 


1560 1 877 


50 2 


NA 


NA 


m 


NA 


NA 


i^m^ 


NA 


NA 


■Uv 


NA 


NA l^' 


NA 


NA 


'351' 


51 


840 ^'4f77::: 


61 1106 


633 


72 1413 


'812 


99 


2080 j 1243' 

j 


5 


NA 


NA 


■NA' 


NA 


NA 


mK 


NA 


NA 


;i5r 


NA 


NA ^230' 


NA 


NA 


323 


83 


819 n"4455: 


98 1083 


596 


116 1387 


■774 


155 


2052 J1225 


10 


NA 


NA 


W- 


NA 


NA 


|nA- 


NA 


NA 


:138' 


NA 


NA 2|5' 


NA 


NA 


304 


NA 


NA p'^4^' 


126 1047 


567 


147 1347 


733 


195 


2006^1147 


15 


NA 


NA 


NA- 


NA 


NA 


]^K\ 


NA 


NA 


M- 


NA 


NA hi^9^ 


NA 


NA 


282 


NA 


NA j;'*400; 


146 1010 


539 


170 1307 


702 


222 


1961 1099 


20 


NA 


NA 


?B-- 


NA 


NA 


%f; 


NA 


NA 


,nA 


NA 


NA \im 


NA 


NA 


264 


NA 


NA I"- 376 : 


165 


977 


511 


190 1269 


669 


246 


1916 1050 


30 


NA 


NA 


.NA 


NA 


NA 


^?^a" 


NA 


NA 


,NA 


NA 


NaInA, 


NA 


NA 


NA 


NA 


NA i- -327; 


NA 


NA 


468 


233 1196 


,623 


295 


1832 984 


Minimum 




12 


::z. 




19 


1.' ':- 




28 






38 1 'B- 




50 






63 i: t 




78 




95 


; 




132 


internal 












l^-'v 










h-iv: 










•:.'■':•• 










' 






area of 






%^. 






Z\-^' - 
















i.. 




f:-- v- 
















chimney 
(in.^) 






ML 






Z" 










ill 






•::.. 




r'' I-, 
















Maximum 




49 


t::.: 




88 


::\-:~ 




137 






198 i;i-.. 




269 






352 fi-:.'i 




445 




550 






792 ' 


internal 












.•; ''"- 










Tfr'- 






;>'■■■■ 




,:::i'i: 














! 


area of 






^^;:i 












. ;.jt. 




























1 


chimney 
(in.2) 


















li ;;■;'; 




ife 



























For SI units, 1 in. = 25.4 mm, 1 ft = 0.305 m, 1000 Btu/hr = 0.293 kW, 1 in.^ = 645 mm^ 



2002 Edition 



54-94 



NATIONAL FUEL GAS CODE 



ANSI Z223.1-94 



Table 13.4 Masonry Chimney 


























































Number of y^ipliances: 






Singl 


s 






Appliance Type: 


Category I 




Appliance Vent Connection: 


Single Wall Metal Connector 


















Single-Wall Metal Connector Diameter — D (in.) 


























To be used with 


chimney areas within the size limits at bottom 










3 


4 


5 


6 


7 


8 


9 


10 


12 
















Appliance Input Rating 


m Thousands of Btu per Hour 










He 


ight Lateral 
H L 

ft) (ft) 


FAN 1 


4at 

\fax 


FAN r 


'^ATr 
Max, 


FAN : 


VAt; 

Max 


FAN 


VAT^ 

Max 


FAN 


VAT 
^ax. 


FAN 


>jat:: 

Max 


FAN 


VAT; 


FAN 


fAT, 
Mix, 


FAN NAT 


( 


Min Max 


Min Max ; 


Min 


Max 


Min 


Max 


Min Max 


Min Max 


Min Max 


Min Max 


Min Max Max 


6 


2 


NA 


NA 


:;28 


NA 


NA! 


' 52' 


NA 


NA 


86 


NA 


NA 


130 


NA 


NA 


l80 


NA 


NA 


247 


NA 


NA 


310. 


NA NA 


*466 


NA NA[580J 




5 


NA 


NA 


■•\2b- 


NA 


NA 


.•■■48:^ 


NA 


NA 


■'■81; 


NA 


NA H$& 


NA 


NA 


:i64' 


NA 


NA 


f230i 


NA 


NA 


297: 


NA NA 


■375^ 


NA NA ^560, 


8 


2 


NA 


NA 


'^^■^ 


NA 


NA. 


'^55.^' 


NA 


NA 


^ 93'' 


NA 


NA 


^i;45; 


NA 


NA 


ii97? 


NA 


NA 


?265i 


NA 


NA 


349- 


382 725 


4'45: 


549 1021 ?65q 




5 


NA 


NA 


;:26 


NA 


NA 


51. 


NA 


NA 


87 


NA 


NA 


133 


NA 


NA 


.182 


NA 


NA 


'246: 


NA 


NA 


.327; 


NA NA 


422: 


673 1003 .,638 




8 


NA 


NA 


^r23 


NA 


NAr 


-47-: 


NA 


NA 


82 


NA 


NA 


1'26~ 


NA 


NA 


174 


NA 


NA 


237' 


NA 


NA 


317 


NA NA 


408 


747 985 "-62^ 


10 


2 


NA 


NA 


; 31 ' 


NA 


NA 


'■■61;' 


NA 


NA 


'ld2- 


NA 


NA 


161- 


NA 


NA 


"22tf 


216 


518 


'297; 


271 


654 


*38r 


373 808 


490' 


536 1142 !722 




5 


NA 


NA 


'V2& 


NA 


NA 


;-.56; 


NA 


NA 


95 


NA 


NA 


147. 


NA 


NA 


.203, 


NA 


NA 


:276:- 


334 


635 


364: 


459 789 


1465. 


657 1121 ,710 




10 


NA 


NA 


;?24 


NA 


NA. 


;'49; 


NA 


NA 


86 


NA 


NA 


ir?^ 


NA 


NA 


189 


NA 


NA 


261- 


NA 


NA 


345 


547 758 


441 


771 1088 665 


15 


2 


NA 


NA 


;35 


NA 


NA 


■■■67; 


NA 


NA 


lis- 


NA 


NA 


1.78 


166 


473 


'249 


211 


611 


'■335; 


264 


776 


440 


362 965 


560- 


520 1373 I 840 




5 


NA 


NA 


':32. 


NA 


NA 


,61. 


NA 


NA 


106; 


NA 


NA 


. 163; 


NA 


NA 


;230; 


261 


591 


•312; 


325 


755 


|414; 


444 942 


;531 


637 1348 '825 




10 


NA 


NA 


;:27 


NA 


NA 


' 54: 


NA 


NA 


96 


NA 


NA 


151 


NA 


NA 


214 


NA 


NA 


294 


392 


722 


392 


531 907 


504 


749 1309 1774 




15 


NA 


NA 


;NA- 


NA 


NA 


;,-46; 


NA 


NA 


-87^ 


NA 


NA 


138 • 


NA 


NA 


a:98? 


NA 


NA 


^278- 


452 


692 


. 372; 


606 873 


^8;i* 


841 1272 ■!738 


20 


2 


NA 


NA 


i38-: 


NA 


NA 


^^73"; 


NA 


NA 


•123 


NA 


NA 


;25o 


163 


520 


;273; 


206 


675 


.■'374-'i 


258 


864 


.490: 


252 1079 


'"625: 


508 1544 [950 




5 


NA 


NA 


:35 


NA 


NA 


67 ■ 


NA 


NA 


115 


NA 


NA 


183 


NA 


NA 


252 


255 


655 


£348, 


317 


842 


46i: 


433 1055 


594 


623 1518:930, 




10 


NA 


NA 


■.NA. 


NA 


NA 


;=59l 


NA 


NA 


■105' 


NA 


NA 


170- 


NA 


NA 


■:235= 


312 


622 


;'330- 


382 


806 


'437^ 


517 1016 


'562; 


733 1475 : 875 




15 


NA 


NA 


NA 


NA 


NA 


:NA; 


NA 


NA 


95 


NA 


NA 


156 


NA 


NA 


.'217 


NA 


NA 


311; 


442 


773 


.4.14: 


591 979 


.539 


823 1434 1835 




20 


NA 


NA 


_;NA 


NA 


NA 


-na: 


NA 


NA 


80 


NA 


NA 


l& 


NA 


NA 


202 


NA 


NA 


;292: 


NA 


NA 


392- 


663 944 


510 


911 1394 18OO 


30 


2 


NA 


NA 


*f*4f 


NA 


NA 


8r 


NA 


NA 


136' 


NA 


NA 


2;15 


158 


578 


■302 


200 


759 


|420; 


249 


982 


556 ■■ 


340 1237 


■715' 


489 1789 ind 




5 


NA 


NA 


■fvIA- 


NA 


NA 


^.^75'- 


NA 


NA 


'\if 


NA 


NA 


'%'6 

■■; 


NA 


NA 


■279' 


245 


737 


39i: 


306 


958 


'ski 


417 1210 


'680 


600 1760 109Q 




10 


NA 


NA 


'NA 


NA 


NA 


': 66- 


NA 


NA 


113' 


NA 


NA 


f82 


NA 


NA 


260 


300 


703 


:3'70 


370 


920 


496; 


500 1168 


W 


708 1713 1020 




15 


NA 


NA 


'NA 


NA 


NA 


NA 


NA 


NA 


105 


NA 


NA 


168 


NA 


NA 


240 


NA 


NA 


■349: 


428 


884 


471.' 


572 1128 


f '.;•■'■ ■ 
615 


798 1668 :*.975' 




20 


NA 


NA 


:NA' 


NA 


NA 


,NA; 


NA 


NA 


- 88.. 


NA 


NA 


155: 


NA 


NA 


223 


NA 


NA 


:327; 


NA 


NA 


445' 


643 1089 


'585' 


883 1624 f932. 




30 


NA 


NA 


• NA 


NA 


NA 


NA 


NA 


NA 


NA 


NA 


NA 


NA 


NA 


NA 


182 


NA 


NA 


281. 


NA 


NA 


408 


NA NA 


544 


1055 1539 ; 865 


50 


2 


NA 


NA 


= N[A 


NA 


NA 


91; 


NA 


NA 


160; 


NA 


NA 


250 


NA 


NA 


350 


191 


837 


U75i 


238 1103 


-631; 


323 1408 


810; 


463 2076 124q 




5 


NA 


NA 


:NA 


NA 


NA 


;m- 


NA 


NA 


149 


NA 


NA 


' .;' ■ ■ 

228 


NA 


NA 


321 


NA 


NA 


f442i 


293 1078 


593 , 

'■ ■■■■ •:, 


398 1381 


i?o 


571 2044 1220 




10 


NA 


NA 


.NA 


NA 


NA 


■NA, 


NA 


NA 


136 


NA 


NA 


212 


NA 


NA 


;30.L 


NA 


NA 


'J42Q;. 


355 1038 


.562;: 


447 1337 


;7:28 


674 1994 1140 




15 


NA 


NA 


-MA, 


NA 


NA 


■;NA 


NA 


NA 


,124: 


NA 


NA 


;195, 


NA 


NA 


.:278 


NA 


NA 


:^95; 


NA 


NA 


;533 


546 1294 


.695, 


761 1945 1090 

f 1 




20 


NA 


NA 


;NA. 


NA 


NA 


..na; 


NA 


NA 


..NA. 


NA 


NA 


;i8p. 


NA 


NA 


•^258i 


NA 


NA 


IflQi 


NA 


NA 


!:504:. 


616 1251 


;660. 


844 1898 104d 




30 


NA 


NA 


-'NA^ 


NA 


NA 


|na: 


NA 


NA 


jNA 


NA 


NA 


iisik 


NA 


NA 


■'■NA: 


NA 


NA 


;i318^. 


NA 


NA 


::458; 


NA NA 


'&m 


1009 1805 r97d 




Minimum 




12 


V.--:... 




19 






28 


- ' . ■<'^ I 




38 


'■•y/ji' 




50 






63 


r. : ,,- 




78 




95 


1(111;; 


132-; -i 




internal area 
























.:::. 












i: .- 






1 .-;.■; 






1. 1 




of chimney 
(in.^) 






t7" 
























... 






fr 






;■■■ =■-.';;: 




'J? 


r i 




Maximum 




49 


7- ■ 




88 






137 


: ~j 




198 


'■•i-J' 




269 






352 


?■:. 




445 


1 ""' 


550 


?H 


792 i 1 




internal area 












•?-;■.-■ 












r^w:' 






Prt»:., 












!.;;;;,;:- 




f!lf ■ 


^- 1 




of chimney 
(in.^) 






If'' 












i ■■;. 






:#■ 












t. : 






! ■;; 




w 


i... 1 

r "i 



For SI units, 1 in. = 25.4 mm, 1 ft = 0.305 m, 1000 Btu/hr = 0.293 kW, 1 in.^ = 645 mm^ 



2002 Edition 



ANSI Z223.1-95 



SIZING OF CATEGORY I VENTING SYSTEMS 



54-95 



Table 13.5 


Single-Wall Metal Pipe oi 


Type B Asbestos Cement Vent 


















Number of i^jpliances: 


Single 




^pliance Type: 


Draft Hood-Equipped 




AppUance Vent Connection: 


Connected Directly to Pipe or Vent 










Diameter - D (in.) 






Lateral 






To be used with chimney areas within the size limits at bottom 






3 


4 


5 


6 


7 


8 


10 


12 




Appliance Input Rating in Thousands of Btu per Hour 


Height 










H 


L 










(ft) 


(ft) 






Maximum Appliance Input Rating in Thousands of Btu per Hoiu- 




6 





39 


70 


116 


170 


232 


312 


500 


750 




2 


31 


55 


94 


141 


■ 194 


260 


415 


620 




5 


28 


51 


88 


128 


177 


242 


390 


600 


8 





42 


76 


126 


185 


252 


340 


542 


815 




2 


32 


61 


102 


154 


210 


284 


451 


680 




5 


29 


56 


95 


141 


194 


264 


430 


648 




10 


24 


49 


86 


131 


180 


250 


406 


625 


10 





45 


84 


138 


202 


279 


372 


606 


912 




2 


35 


67 


111 


168 


233 


311 


505 


760 




5 


32 


61 


104 


153 


215 


289 


480 


724 




10 


27 


54 


94 


143 


200 


274 


455 


700 




15 


NA 


46 


84 


130 


186 


258 


432 


666 


15 





49 


91 


151 


223 


312 


420 


684 


1040 




2 


39 


72 


122 


186 


260 


350 


570 


865 




5 


35 


67 


110 


170 


240 


325 


540 


825 




10 


30 


58 


103 


158 


223 


308 


514 


795 




15 


NA 


50 


93 


144 


207 


291 


488 


760 




20 


NA 


NA 


82 


132 


195 


273 


466 


726 


20 





53 


101 


163 


252 


342 


470 


770 


1190 




2 


42 


80 


136 


210 


286 


392 


641 


990 




5 


38 


74 


123 


192 


264 


364 


610 


945 




10 


32 


65 


115 


178 


246 


345 


571 


910 




15 


NA 


55 


104 


163 


228 


326 


550 


870 




20 


NA 


NA 


91 


149 


214 


306 


525 


832 


30 





56 


108 


183 


276 


384 


529 


878 


1370 




2 


44 


84 


148 


230 


320 


441 


730 


1140 




5 


NA 


78 


137 


210 


296 


410 


694 


1080 




10 


NA 


68 


125 


196 


274 


388 


656 


1050 




15 


NA 


NA 


113 


177 


258 


366 


625 


1000 




20 


NA 


NA 


99 


163 


240 


344 


596 


960 




30 


NA 


NA 


NA 


NA 


192 


295 


540 


890 


50 





NA 


120 


210 


310 


443 


590 


980 


1550 




2 


NA 


95 


171 


260 


370 


492 


820 


1290 




5 


NA 


NA 


159 


234 


342 


474 


780 


1230 




10 


NA 


NA 


146 


221 


318 


456 


730 


1190 




15 


NA 


NA 


NA 


200 


292 


407 


705 


1130 




20 


NA 


NA 


NA 


185 


276 


384 


670 


1080 




30 


NA 


NA 


NA 


NA 


222 


330 


605 


1010 



For SI units, 1 in. = 25.4 mm, 1 ft = 0.305 m, 1000 Btu/hr = 0.293 kW, 1 in.^ = 645 mm^ 



2002 Edition 



54-96 



NATIONAL FUEL GAS CODE 



ANSI Z223. 1-96 



hood outlet area unless designed in accordance with ap- 
proved engineering methods. 

13.1.9 Exterior Chimneys and Vents. Table 13.1 through 
Table 13.5 shall be used for chimneys and vents not exposed to 
the outdoors below the roof line. A Type B vent or Hsted chim- 
ney lining system passing through an unused masonry chim- 
ney flue shall not be considered to be exposed to the out- 
doors. Table 13.3 in combination with Table 13.11 shall be 
used for clay-tile-lined exterior masonry chimneys, provided 
all of the following requirements are met: 

(1) The vent connector is Type B double wall. 

(2) The vent connector length is limited to 18 in. /in. 
(18 mm/mm) of vent connector diameter. 

(3) The appliance is draft hood-equipped. 

(4) The input rating is less than the maximum capacity given 
in Table 13.3. 

(5) For a water heater, the outdoor design temperature shall 
not be less than 5°F (-15°C). 

(6) For a space-heating appliance, the input rating is greater 
than the minimum capacity given by Table 13.11. 

Exception: Vents serving listed appliances installed in accordance 
with the appliance manufacturer's instructions and the terms of the 
listing. 

13.1.10 Corrugated Vent Connector Size. Corrugated vent 
connectors shall not be smaller than the listed appliance cat- 
egorized vent diameter, flue collar diameter, or draft hood 
outlet diameter. 

13.1.11 Upsizing. Vent connectors shall not be upsized more 
than two sizes greater than the listed appliance categorized 
vent diameter, flue collar diameter, or draft hood outlet diam- 
eter. 

13.1.12 Multiple Vertical Vent Sizes. In a single run of vent or 
vent connector, more than one diameter and type shall be 
permitted to be used, provided that all the sizes and types are 
permitted by the tables. 

13.1.13 Interpolation. Interpolation shall be permitted in cal- 
culating capacities for vent dimensions that fall between table 
entries. (See Example 3, Annex G.) 

13.1.14 Extrapolation. Extrapolation beyond the table entries 
shall not be permitted. 

13.1.15 Sizing Vents not Covered by Tables. For vent heights 
lower than 6 ft and higher than shown in the tables, engineer- 
ing methods shall be used to calculate vent capacities. 

13.2 Additional Requirements to Multiple Appliance Vent 
Table 13.6 Through Table 13.13(a) and Table 13.13(b). 

13.2.1 Obstructions and Vent Dampers. These venting tables 
shall not be used where obstructions (see Section 10.15) are 
installed in the venting system. The installation of vents serv- 
ing listed appliances with vent dampers shall be in accordance 
with the appliance manufacturer's instructions, or in accor- 
dance with the following: 

(1) The maximum capacity of the vent connector shall be 
determined using the NAT Max column. 

(2) The maximum capacity of the vertical vent or chimney 
shall be determined using the FAN+NAT column when 
the second appliance is a fan-assisted appliance, or the 
NAT+NAT column when the second appliance is 
equipped with a draft hood. 



(3) The minimum capacity shall be determined as if the ap- 
pliance were a fan-assisted appliance, as follows: 

(a) The minimum capacity of the vent connector shall be 
determined using the FAN Min column. 

(b) The FAN+FAN column shall be used when the second 
appliance is a fan-assisted appliance, and the FAN+NAT 
column shall be used when the second appliance is 
equipped with a draft hood, to determine whether the 
vertical vent or chimney configuration is not permitted 
(NA) . Where the vent configuration is NA, the vent con- 
figuration shall not be permitted and an alternative 
venting configuration shall be utilized. 

13.2.2 Vent Connector Maximum Length. The maximum vent 
connector horizontal length shall be 18 in. /in. (18 mm/mm) 
of connector diameter as shown in Table 13.2.2. 

13.2.3 Vent Connector Exceeding Maximum Length. The 

vent connector shall be routed to the vent utilizing the short- 
est possible route. Connectors with longer horizontal lengths 
than those listed in Table 13.2.2 are permitted under the fol- 
lowing conditions: 

(1) The maximum capacity (FAN Max or NAT Max) of the 
vent connector shall be reduced 10 percent for each addi- 
tional multiple of the length listed in Table 13.2.2. For 
example, the maximum length listed for a 4-in. (100-mm) 
connector is 6 ft (1 .8 m) . With a connector length greater 
than 6 ft (1.8 m) but not exceeding 12 ft (3.7 m), the 
maximum capacity must be reduced by 10 percent (0.90 
X maximum vent connector capacity). With a connector 
length greater than 12 ft (3.7 m) but not exceeding 18 ft 
(5.5 m), the maximum capacity must be reduced by 
20 percent (0.80 x maximum vent capacity). 

(2) For a connector serving a fan-assisted appliance, the mini- 
mum capacity (FAN Min) of the connector shall be deter- 
mined by referring to the corresponding single appliance 
table. For Type B double-wall connectors. Table 13.1 shall 
be used. For single-wall connectors, Table 13.2 shall be 
used. The height (H) and lateral (L) shall be measured 
according to the procedures for a single appliance vent, 
as if the other appliances were not present. 

Table 13.2.2 Vent Connector Maximum Length 



Connector 
Diameter 
Maximum 

(in.) 



Connector 

Horizontal 

Length 

(ft) 



3 
4 
5 
6 
7 
8 
9 

10 
12 
14 
16 
18 
20 
22 
24 



41/2 

6 

71/2 

9 

101/2 
12 
131/2 
15 
18 
21 
24 
27 
30 
33 
36 



For SI units, 1 in. = 25.4 mm; 1 ft = 0.305 m. 



2002 Edition 



ANSI Z223. 1-97 



SIZING OF CATEGORY I VENTING SYSTEMS 



54-97 



Table 13.6 Type B Double-Wall Vent 





Number of Appliances: 


Two or More 




Appliance Type: 


Category I 




Appliance Vent Connection: 


Type B Double Wall Connector 



Vent Connector Capacity 





















Type B Double-Wall Vent and Connector Diameter — 


D(\n.) 
















3 


4 


5 


6 


7 


8 


9 


10 


Vent C 
















Appliance 


Input Rating Limits in Thousands of Btu per 


Hour 














Height 
H 

(ft) 


Rise 
R 

(ft) 


FAN 


NAT 


FAN 1 


sIAT 


FAN 'NAT 


FAN JNAT' 


FAN ;NAT 


FAN NAT 


FAN 


NAT 
Max 


FAN 


NAT 


Min 


Max 


Min 


Max 


Min 


Max ''I^ax'' 


Min 


Max 1 Max 


Min 


Max iMiix.- 


Min 


Max Max 


Min 


Max 


Mm 


Max 


Max 


6 


1 


22 


37 


26 


35 


66 


M 


46 


106 i;^:72 


58 


164 \- 104 


77 


225 i 142i 


92 


296 : 185 


109 


376 


237 


128 


466 


289 




2 


23 


41 


r'Sir 


37 


75 


-;55; 


48 


121 ;;i;86: 


60 


183 tl24^ 


79 


253 ;•: 168 : 


95 


333 : ;220 


112 


424 


282 


131 


526 


345 




3 


24 


44 


35; 


38 


81 


62 


49 


132 ;"; 96 


62 


199 1 139 


82 


275 [ 189 


97 


363 ! 248 


114 


463 


317 


134 


575 


386 


8 


1 


22 


40 


■'^27^ 


35 


72 


■9^ 


49 


lu'ii'W 


64 


176 Pl09? 


84 


243 > 148* 


100 


320 Ul94 


118 


408 


248 


138 


507 


303 




2 


23 


44 


32: 


36 


80 


57 


51 


128 *:'90 


66 


195 1 129 


86 


269 175 


103 


356 230 


121 


454 


294 


141 


564 


358 




3 


24 


47 


-,,-M 


37 


87 


64^ 


53 


139 i\Wl, 


67 


210 ij 145[, 


88 


290 J 198: 


105 


384 ; 258 


123 


492 


330 


143 


612 


402 


10 


1 


22 


43 


28 


34 


78 


50 


49 


123 ■'■'78 


65 


189 ! 113 


89 


257 I 154 


106 


341 ; 200 


125 


436 


257 


146 


542 


314 




2 


23 


47 


33 


36 


86 


,,59: 


51 


136 ;;ji93 


67 


206 1. 134 


91 


282 ; 182 


109 


374 i 238 


128 


479 


305 


149 


596 


372 




3 


24 


50 


■'■?ri[ 


37 


92 


w 


52 


146 f!aQ4 


69 


220 n 150- 


94 


303 r2b5 


111 


402 268 


131 


515 


= 342 


152 


642 


417 


15 


1 


21 


50 


.> 30: 


33 


89 


;53; 


47 


142 ii83, 


64 


220 [ 120 


88 


298 1 163 


110 


389 : 214 


134 


493 


273 


162 


609 


333 




2 


22 


53 


-35^ 


35 


96 


■63-: 


49 


153 -1:99^ 


66 


235 r 142 


91 


320 1 ■ 193^ 


112 


419 253 


137 


532 


: 323 


165 


658 


394 




3 


24 


55 


40 


36 


102 


71 


51 


163 uUl 


68 


248 1 I6O; 


93 


339 i 218 


115 


445 286 


140 


565 


365 


167 


700 


444 


20 


1 


21 


54 


'■3L 


33 


99 


•bi- 


46 


157 fy=87' 


62 


246 '125; 


86 


334 p 171: 


107 


436 ^224 


131 


552 


285 


158 


681 


347 




2 


22 


57 


37; 


34 


105 


66. 


48 


167 \H04 


64 


259 ; 149 


89 


354 i 202 


110 


463 265 


134 


587 


339 


161 


725 


414 




3 


23 


60 


!;>42t 


35 


110 


;;74; 


50 


176 ipiiift; 


66 


271 b:i^8= 


91 


371 [228; 


113 


486 ::300 


137 


618 


383 


164 


764 


466 


30 


1 


20 


62 


33 


31 


113 


59 


45 


181 : 93 


60 


288 i 134 


83 


391 ■ 182 


103 


512 238 


125 


649 


305 


151 


802 


372 




2 


21 


64 


;.39; 


33 


118 


; 70 


47 


190 ^i'ilO; 


62 


299 ',,158 


85 


408 \ 215= 


105 


535 '■■.282 


129 


679 


360 


155 


840 


439 




3 


22 


66 


■ -^44= 


34 


123 


79 


48 


198 ;;li24' 


64 


309 f 178- 


88 


423 1 242' 


108 


555 r'3l7 


132 


706 


405 


158 


874 


494 


50 


1 


19 


71 


:3:6: 


30 


133 


m; 


43 


216 i^iOl 


57 


349 M45; 


78 


477 ; 197 


97 


627 L257 


120 


797 


, 330 


144 


984 


403 




2 


21 


73 


:43; 


32 


137 


•16 


45 


223 ;:i:i9 


59 


358 172; 


81 


490 1 *2'34: 


100 


645 rm 


123 


820 


' 392 


148 


1014 


478 




3 


22 


75 


48; 


33 


141 


86 


46 


229 ^ !134 


61 


366; 194, 


83 


502 1 263 


103 


661 I 343 


126 


842 


441 


151 


1043 


538 


100 


1 


18 


82 


"'^71. 


28 


158 


'M 


40 


262 rri64 


53 


442 ii-isO; 


73 


611 j 264 ■ 


91 


810 [266 


112 


1038 


341 


135 


1285 


417 




2 


19 


83 


44; 


30 


161 


79 


42 


267 r:i23 


55 


447 ^ 178 


75 


619 i 242 


94 


822 1 316 


115 


1054 


405 


139 


1306 


494 




3 


20 


84 


4,60- 


31 


163 


.89' 


44 


272 f-138 


57 


452 >,20q 


78 


627 ; -27.2; 


97 


834 1<.355 


118 


1069 


455; 


142 


1327 


555 



Common Vent Capacity 











Type B Double-Wall Common Vent Diameter — D ( 


in.) 














4 


5 


6 


7 


8 


9 


10 


Vent 


Combined Appliance Input Rating in Thousands of Btu per Hour 


Height 
H 

(ft) 


FAN FAN 


■-'NATii 


FAN 


FAN 


?;nat; 


FAN FAN 


■INAT- 


FAN 


FAN [=NAT^ 


FAN FAN 


\ NAT" 


FAN FAN 


NAT 


FAN 


FAN 


NAT 


+FAN +NAT 


, +NAT 


fFAN 


+NAT 


h+NAT. 


+FAN +NAT 


;+NAT 


fFAN 


+NAT If^AT 


+FAN +NAT 


j+NAT 


+FAN +NAT 


+NAT 


+FAN 


+NAT 


+NAT 


6 


92 81 


65;;; 


140 


116 


•163'"=^ 


204 161 


147 


309 


248 !:200* 


404 314 


■26q;v' 


547 434 


335' 


672 


520 


410 


8 


101 90 


■ 73;-; 


155 


129 


1114 ;« 


224 178 


; 163 


339 


275 |223 


444 348 


;290: 


602 480 


378 


740 


577 


465 


10 


110 97 


'--■79Hi 


169 


141 


i;124'J'":- 


243 194 


■.178 ■ ■■ 


367 


299 >:242 


477 377 


■ 315' r: 


649 522 


405.; 


800 


627 


4.95 


15 


125 112 


9lf: 


195 


164 


ri44 .;i 


283 228 


"206 


427 


352 [km 


556 444 


365" 


753 612 


465 * 


924 


733 


565 


20 


136 123 


\ 102;:,. 


215 


183 


;-:160...r. 


314 255 


;229 


475 


394 ;,310 


621 499 


! 405.; 


842 688 


523 


1035 


826 


640 


30 


152 138 


r^'ili-:; 


244 


210 


ia^S'H: 


361 297 


;266: 


547 


459 H360- 


720 585 


:47G^;;; 


979 808 


605 


1209 


975 


740 


50 


167 153 


134i: 


279 


244 


r2i4 -% 


421 353 


C'310 


641 


547 [423 


854 706 


\ 550,; 


1164 977 


705 


1451 


1188 


860 


100 


175 163 


h. NA*:.- 


311 


277 


rNA;;n 


489 421 


''NA . , 


751 


658 :;479^ 


1025 873 


!:625.:;; 


1408 1215 


800,. 


1784 


1502 


975 



2002 Edition 



54-98 



NATIONAL FUEL GAS CODE 



ANSI Z223. 1-98 



Table 13.6 Continued 











Number of y^pUances: 




Two or More 




Appliance Type: 


Category I 






Appliance Vent Connection: 


Type B Double Wall Connector 




Type B Double-Wall Vent and Connector Diameter — D (in.) 




12 


14 


16 


18 


20 


22 


24 




Appliance Input Rating Limits in Thousands of Btu per Hour 


Height Rise 
H R 

(ft) (ft) 


FAN 'mM: 


FAN .NAt; 


FAN NAT 


FAN 


;NAt;' 

.IVf^. 


FAN 


Max: 


FAN ^nat; 


FAN pNATJ 


Min Max v Max 


Min Max Max 


Min Max Max 


Min Max 


Min Max 


! ■ - ; 

Min Max ; Max- 


Min Max i Max j 


6 2 
4 
6 


174 764 ^r496 
180 897 i;;616 

NA NA R;i>JA^ 


223 1046 -'W. 
230 1231 ^ .8^7 
NA NA 'j-f'NA.; 


281 1371 ;853 
287 1617 1081 

NA NA InA. 


346 1772 TldSO 
352 2069 1 1370 

NA NA pNA- 


NA NAp'NA 
NA NAJ .jNA 
NA NA;^;jNA: 


NA NA r; 'nA^ 
NA NaK.. NAJ 
NA NAi-^'hNA 


NA NA r n'A 
NA NA f M^ 

NA na';*\nA 


8 2 
4 
6 


186 822 ;:;;516 
192 952 IH644; 
198 1050^^772 


238 1126 696, 
244 1307 ;.:i80: 
252 1445 1072 


298 1478^910 
305 1719 V150i 
313 1902 1390 


365 1920 "' 1150 
372 2211 vmO^- 
380 2434 ; 1770 


NA NA 1 m 
471 2737 ^-1800^ 
478 3018 ; 2l'86 


NA NA ^' ;NA' 
560 3319;:;2i80; 
568 3665 f 2640; 


NA NA ,; NA 
662 3957 :* 2590 
669 4373, 31 30 


10 2 
4 
6 


196 870 M?536- 
201 997 ;-664 
207 1095 ';..792 


249 1195 i ;73fl: 
256 1371 924 
263 1509 1118. 


311 1570 :^55 
318 1804 1205 
325 1989 1455 


379 2049 'hBs 
387 2332 ; 1535 
395 2556 1.1865 


NA NA-y-mj^ 
486 2887 j 1890 
494 3169 [ 2290. 


NA NA ;.-i-- JM-; 
581 3502 f 2280; 
589 3849 l,TI^: 


NA NA i; ■ NA 
686 4175 f, 2710 
694 4593 ^■3270 


15 2 
4 
6 


214 967 f'568 
221 1085 1; 712 
228 1181 ^>856^ 


272 1334 ■ 790 
279 1499 1006' 
286 1632 :'12~2| 


336 1760 1030 
344 1978 1320 
351 2157 16*10' 


408 2317 I 1305 
416 2579:1665 
424 2796 f2025^ 


NA NA: '~NA* 
523 3197 j ,2060 
533 3470H:25ld; 


NA NA j NA: 
624 3881 i 2490= 
634 4216 \i:S(^0\ 


NA NA ; NA 
734 4631 ■ > 2m 
743 5035 ^;:360Q 


20 2 
4 
6 


223 1051 11596 
230 1162 ;h7^81 
237 1253 PgOO 


291 1443 > 840 
298 1597 ! 1064H 
307 1726 1288. 


357 1911 1095 
365 2116 1595' 
373 2287 1695 


430 2533 
438 2778 
450 2984 


1385 

'1765^ 
2145 


NA NA i ,.NA 
554 3447 i~ ^2180 
567 3708 ! 2650 


NA NAL..NA: 
661 4190 ;J- 2830;: 
671 4511 1 319()' 


NA NAh^.NA 
772 5005 'nh% 
785 5392 f. 3790 


30 2 
4 
6 


216 1217 ^^63^- 
223 1316 :; 792 
231 1400 ^.^52. 


286 1664-^910^ 
294 1802 1160 
303 1920 ., 141:0: 


367 2183 1%; 
376 2366 1510 
384 2524 1830 


461 2891 
474 3110 
485 3299 


1540; 
1920 
23;40; 


NA NAv''M^ 
619 3840 1 2365 
632 4080 ; , -2875 


NA NA P- 'NA: 
728 4861 r 2866; 
741 4976 .;.3480: 


NA NA;?"nA 
847 5606 \:- 341Q 
860 5961 ;;; 4150 


50 2 
4 
6 


206 1479 r" 689 
213 1561 -^-860 
221 1631 jl031. 


273 2023 1007 
281 2139 1291^ 
290 2242 'l'S75: 


350 2659 1315 
359 2814 :f685 
369 2951 2055 


435 3548 | 1665 
447 3730 j 21^35 
461 3893 f^oH" 


NA NA j "m 
580 4601 ^^ 2633, 
594 4808 -"^bS 


NA NA ;■ NA' 
709 5569 ':, 3185; 
724 5826 •'*3885; 


NA NA ;■ NA 
851 6633 1 . 3790 
867 6943 ^ '4620 


100 2 
4 
6 


192 1923 i ,712 
200 1984 iyj88&-: 
208 2035 l1064. 


254 2644 .1050: 
263 2731 '-1346- 
272 2811 1642: 


326 3490 1370 
336 3606 1760 
346 3714 2150 


402 4707 
414 4842 
426 4968 


1740, 
'2220^ 
2700 


NA NAL;NA 
523 5982 ?' 2750 
539 6143 ! 3350 


NA na;;.;.nA; 

639 7254 ;' 3330; 
654 7453 \ 4070 ; 


NA NaL-NA! 
769 8650 i- 395d 
786 8892 i 481Q 



Common Vent Capacity 

















Type B Double-Wall Common Vent Diameter 


-D(in.) 












12 


14 


16 


18 


20 


22 


24 


Vent 














Combined Appliance 


Input Rating in Thous 


>ands of Btu per Hour 










Height 
H 

(ft) 


FAN 
+FAN 


FAN 
+NAT 


'^AT: 

ffNAT^ 


FAN 
+FAN 


FAN 
+NAT 


Nat 

+NAT 


FAN 

+FAN 


FAN ; NAT: 

+NAT ■+nAt: 


FAN 
+FAN 


FAN \ NAT 
-i-NAT !*NAT: 


FAN 
+FAN 


FAN NAT; 
+NAT iNATj 


FAN 
+FAN 


FAN 
+NAT 


..NAT-- 
.-fNAT 


FAN 
+FAN 


FAN 
+NAT 


.natI 
«+nat: 


6 


900 


696 


:}: 588 


1284 


990 


.-•■SI 5 


1735 


1336 : 1Q65 


2253 


1732 j 1345 


2838 


2180 I66O' 


3488 


2677 


; 1970 


4206 


3226 


. 2390 


8 


994 


773 


;;652: 


1423 


1103 


^;:-:9l2. 


1927 


1491 ; ill90; 


2507 


1936 \a5W 


3162 


2439 ; I860: 


3890 


2998 


:'2200; 


4695 


3616 


;;:268o 


10 


1076 


841 


t;;712^ 


1542 


1200 


;:995 


2093 


1625 ^ 1300 


2727 


2113 i 1645 


3444 


2665 2030= 


4241 


3278 


^.'2400; 


5123 


3957 


: 2920: 


15 


1247 


986 


;.;825^ 


1794 


1410 


.il58 


2440 


1910 1510 


3184 


2484 i ,1910 


4026 


3133 2360: 


4971 


3862 


: 2790 ; 


6016 


4670 


. = -3400 


20 


1405 


1116 


i;^9i:6; 


2006 


1588 


; = ;1290; 


2722 


2147 M69d.^ 


3561 


2798 f:214d^ 


4548 


3552 :v2640; 


5573 


4352 


;;3120; 


6749 


5261 


\3800 


30 


1658 


1327 


ab25 


2373 


1892 


1525 


3220 


2558 : 1990 


4197 


3326 I 2520 


5303 


4193 3110 


6539 


5157 


3680 


7940 


6247 


4480 


50 


2024 


1640 


■;i280. 


2911 


2347 


; 1863 


3964 


3183; 2430 


5184 


4149 i ,3075 


6567 


5240 ■- 3800 ; 


8116 


6458 


;.45.00; 


9837 


7813 


: :5475 


100 


2569 


2131 


;;i^G 


3732 


3076 


-2450' 


5125 


4202 - -32:00 


6749 


5509 4050: 


8597 


6986* 5d6dv 


10,681 


8648 


;:5920. 


13,004 10,499 


- 7200 



For SI units, 1 in. = 25.4 mm, 1 in.^ = 645 mm^, 1 ft = 0.305 m, 1000 Btu per hr ■■ 



0.293 kW. 



2002 Edition 



ANSI Z223. 1-99 



SIZING OF CATEGORY I VENTING SYSTEMS 



54-99 



Table 13.7 Type B Double-Wall Vent 





Number of Appliances: 


Two or More 




Appliance Type: 


Category I 




Appliance Vent Connection: 


Single Wall Metal Connector 



Vent Connector Capacity 





onnector 

Rise 

R 

(ft) 
















Single-Wall Metal Vent Connector Diameter - 


-D(in.) 














3 


4 


5 


6 


7 


8 


9 


10 


Vent C 
















Appliance Input Rating Limits 


in Thousands of Btu per 


Hour 












Height 
H 

(ft) 


FAN 


r«M.T 

Max 


FAN 


-NAT. 
Max 


FAN ^NAT; 


FAN 


NAT 
Mp 


FAN 


NAT 
-.Majc. 


FAN . 


NAT 
Max 


FAN NAT 


FAN NAT 


Min 


Max 


Min 


Max 


Min 


Max .Max' 


Min 


Max 


Min 


Max 


Min 


Max 


Min 


Max Max 


Min 


Max Max 


6 


1 


NA 


NA 


26 


NA 


NA 


, 46 


NA 


NA -.^ 71:, 


NA 


NA 


:102 


207 


223 


.a4Q: 


262 


293 


183 


325 


373 234 


447 


463 286 




2 


NA 


NA 


31 


NA 


NA 


:-^55*' 


NA 


NA r'%z 


168 


182 


123 


215 


251 


167- 


271 


331 


219 


334 


422 281 


458 


524 ' 344 




3 


NA 


NA 


■■^34. 


NA 


NA 


: 62, 


121 


131 :u:^5;- 


175 


198 


:138 


222 


273 


';188i 


279 


361 


247 


344 


462 ; 316 


468 


574 , 385 


8 


1 


NA 


NA 


,27 


NA 


NA 


48', 


NA 


NA l;:75;- 


NA 


NA 


106 


226 


240 


;a45i 


285 


316 


191 


352 


403 : 244 


481 


502 299 




2 


NA 


NA 


32 


NA 


NA 


57 


125 


126 f'^' 


184 


193 


127 


234 


266 


•173: 


293 


353 


228 


360 


450 292 


492 


560 355 




3 


NA 


NA 


■/.35- . 


NA 


NA 


64; 


130 


138 rTOO; 


191 


208 


[144 


241 


287 


\-^-i. 


302 


381 


256 


370 


489 328 


501 


609 400 


10 


1 


NA 


NA 


,28 


NA 


NA 


- 50-. 


119 


121 ;i-:77:: 


182 


186 


iiio 


240 


253 


;15P; 


302 


335 


196 


372 


429 : 252 


506 


534 308 




2 


NA 


NA 


33 


84 


85 


59 


124 


134 ;.; 91- 


189 


203 


132 


248 


278 


■183- 


311 


369 


235 


381 


473 302 


517 


589 368 




3 


NA 


NA 


";36 


89 


91 


- 67" 


129 


144 j.tl02;^ 


197 


217 


1 148 


257 


299 


;:203:! 


320 


398 


265 


391 


511 ; 339 


528 


637 413 


15 


1 


NA 


NA 


i9^ 


79 


87 


^:52' = . 


116 


138 ;^-Ell;: 


177 


214 


,116- 


238 


291 


;158; 


312 


380 


208 


397 


482 ; 266 


556 


596 324 




2 


NA 


NA 


34 


83 


94 


62 


121 


150 t 97' 


185 


230 


.138 


246 


314 


, 189: 


321 


411 


248 


407 


522 317 


568 


646 387 




3 


NA 


NA 


"39^ 


87 


100 


70"' 


127 


160 -log;^ 


193 


243 


157 


255 


333 


!:215=- 


331 


438 


281 


418 


557 360 


579 


690 j 437; 


20 


1 


49 


56 


:30 " 


78 


97 


'■5*- 


115 


152 Wm 


175 


238 


!l20 


233 


325 


il6S^ 


306 


425 


217 


390 


538 \ 276 


546 


664 336 




2 
3 


52 
55 


59 
62 


;36 

^'40 


82 
87 


103 
107 


64: 


120 
125 


163 'aoih 

172 }Vi^^ 


182 
190 


252 
264 


a,44 
164 


243 
252 


346 
363 


;:197 

= 223: 


317 
326 


453 
476 


259 
294 


400 
412 


574 ; 331 
607 ■ 375 


558 
570 


709 ; 403 

750 : 457' 


30 


1 


47 


60 


■^31 


77 


110 


■■575' 


112 


175 r''m 


169 


278 


^i;29 


226 


380 


a75-- 


296 


497 


230 


378 


630 294 


528 


779 ■ 358^ 




2 


51 


62 


•;37,., 


81 


115 


..67,. 


117 


185 i;;106;; 


177 


290 


152 


236 


397 


-208: 


307 


521 


274 


389 


662 : 349 


541 


819 ; 425: 




3 


54 


64 


42 


85 


119 


76 


122 


193 rl20' 


185 


300 


:i72 


244 


412 


: 235- 


316 


542 


309 


400 


690 ; 394 


555 


855 ; 482; 


50 


1 


46 


69 


3^4^ 


75 


128 


" 66'^ 


109 


207 : - 96: 


162 


336 


■137 


217 


460 


- 188* 


284 


604 


245 


364 


768 . 314 


507 


951 ; 384' 




2 


49 


71 


s,:;40 


79 


132 


i 72 . 


114 


215 ;;ai3i 


170 


345 


; 164 


226 


473 


<,223? 


294 


623 


293 


376 


793 : 375 


520 


983 ; 458: 




3 


52 


72 


■45 


83 


136 


8? 


119 


221 1*123^ 


178 


353 


:186 


235 


486 


^252 


304 


640 


331 


387 


816 423 


535 


1013 ; 518 


100 


1 


45 


79 


'^4 


71 


150 


61 


104 


249 ■; 9^- 


153 


424 


140 


205 


585 


192' 


269 


774 


249 


345 


993 321 


476 


1236 : 393 




2 


48 


80 


!^'41' 


75 


153 


-73'- 


110 


255 H115\ 


160 


428 


1167' 


212 


593 


228- 


279 


788 


299 


358 


1011 383 


490 


1259 i 469 




3 


51 


81 


j46 


79 


157 


85, 


114 


260 ^:129\ 


168 


433 


190 


222 


603 


256. 


289 


801 


339 


368 


1027 , 431 


506 


1280 527 



Common Vent Capacity 





Type B Double-Wall Vent Diameter — D (in.) 




4 


5 


6 


7 


8 


9 


10 


Vent 














Combined Appliance 


Input Rating in Thousa 


nds of Btu per Hour 












Height 




! 






























H 


FAN 


FAN i 


NAT^ 


FAN 


FAN 


NAT; 


FAN 


FAN i NAT 


FAN FAN ! NAT; 


FAN FAN NAT 


FAN 


FAN 


NAT 


FAN 


FAN 


NAT 


(ft) 


+FAN 


+NAT f 


+NAT^ 


i-FAN 


+NAT 


+NAT 


+FAN +NAT :-+NAT 


+FAN +NAT r+NAT' 


hFAN +NAT *+NAT- 


+FAN 


+NAT 


+NAT 


hFAN 


+NAT 


'+NAT! 


6 


NA 


78 


' -^'64: 


NA 


113 


;■'•■' 9'9- 


200 


158 ["144 


304 244!:' ''196; 


398 310 -: 257; 


541 


429 


332 


665 


515 


407 


8 


NA 


87 


„ ■'. 71 


NA 


126 


,;, 111 


218 


173 ; 159 


331 269 1:. 218 


436 342 ;;;285 


592 


473 


373 


730 


569 


460 


10 


NA 


94 


■ ■■^■'76 


163 


137 


■''12G 


237 


189 r 'i;74 


357 292 n-'236 


467 369 ';■ 309 


638 


512 


398 


787 


617 


487 


15 


121 


108 


:;,88 


189 


159 


[{; 140. 


275 


221 L-200 


416 343 h- -274 


544 434 :;;;357: 


738 


599 


456 


905 


718 


553 


20 


131 


118 


- 98 


208 


177 


i 156 


305 


247 ! 223 


463 383 1-- 302 


606 487 ' 395 


824 


673 


512 


1013 


808 


626 


30 


145 


132 


-113; 


236 


202 


■;::180,: 


350 


286 1-257 


533 446 .n349: 


703 570 :i/,459: 


958 


790 


593 


1183 


952 


723 


50 


159 


145 


;128 


268 


233 


:: 208 


406 


337 : 296 


622 529 :410^ 


833 686 535 


1139 


954 


689 


1418 


1157 


838 


100 


166 


153 


:;na' 


297 


263 


J.NA: 


469 


398 r NA' 


726 633 hr'464; 

i,.-.- ;. 


999 846 j:;:606 


1378 


1185 


780 


1741 


1459 


948 



For SI units, 1 in. = 25.4 mm, 1 in.^ = 645 mm^ 1 ft = 0.305 m, 1000 Btu per hr = 0.293 kW. 



2002 Edition 



54-100 



NATIONAL FUEL GAS CODE 



ANSIZ223.1-100 



Table 13.8 Masonry Chimney 





Number of Appliances: 


Two or More 




Appliance Type: 


Category I 




Appliance Vent Connection: 


Type B Double Wall Connector 



Vent Connector Capacity 





















Type B Double-Wall Vent Connector Diameter 


-D( 


in.) 












3 


4 


5 


6 


7 


8 


9 


10 


Vent C( 
















Appliance Input Rating Limits 


in Thousands of Btu per Hour 










Height 
H 

(ft) 


Rise 
R 

(ft) 


FAN 


NAT 


FAN 


NAT: 
;Max; 


FAN NAT- 


FAN I 


Max 


FAN 


NfAT: 

Max: 


FAN NAT 


FAN [NAT^ 


FAN ;JSJAT 


Min 


Max 


Min 


Max 


Min 


Max Max: 


Min 


Max 


Min 


Max 


Min 


Max Mibc 


Min 


Max -Max 


Min 


Max Max 


6 


1 


24 


33 


^u'il' 


39 


62 


':-40; 


52 


106 y-'&l' 


65 


194 1 lOii 


87 


274 


'i4r 


104 


370 ■ 201 


124 


479 ,'-'253^ 


145 


599 1-319 




2 


26 


43 


28 


41 


79 


■.:,.. 52. 


53 


133 85 


67 


230 i 124 


89 


324 


rl73 


107 


436 232 


127 


562 [, 300 


148 


694:5378 




3 


27 


49 


^■^34: 


42 


92 


i*:m:\ 


55 


155 ^^7 


69 


262 r 143- 


91 


369 


203; 


109 


491 270 


129 


633;: 349 


151 


795 r439 


8 


1 


24 


39 


r^'22' 


39 


72 


H^4i:'- 


55 


117 '^t69 


71 


213 rio5: 


94 


304 


'T48' 


113 


414 216 


134 


539 =■267 


156 


682 1:33^ 




2 


26 


47 


29 


40 


87 


53, 


57 


140 ;86 


73 


246 \ 127 


97 


350 


,;179. 


116 


473 240 


137 


615 : 311; 


160 


776 ; ,394 




3 


27 


52 


; ■ 'i'4t' 


42 


97 


:■ 62^ 


59 


159 ^98 


75 


269 iT45' 


99 


383 


:206 


119 


517 276 


139 


672 \ 358 


163 


848 , 452 


10 


1 


24 


42 


'■'22' 


38 


80 


^^^4^: 


55 


130 ''y1\ 


74 


232 \ \m 


101 


324 


■?i53: 


120 


444 ,216 


142 


582 ;■ 277 


165 


739 1-348 




2 


26 


50 


;„29: 


40 


93 


;l ■.54^' 


57 


153 ;;,87 


76 


261 


129; 


103 


366 


>184 , 


123 


498 .247 


145 


652 ,321; 


168 


825 :^407 




3 


27 


55 


35; 


41 


105 


5 63^ 


58 


170 100 


78 


284 


148 


106 


397 


:209 


126 


540 281 


147 


705 [ 366 


171 


893: 463! 


15 


1 


24 


48 


'"2^ 


38 


93 


'f 44' 


54 


154 ':74 


72 


277 fill 


100 


384 


'164 


125 


511 229 


153 


658 :^' 297' 


184 


824! 375 




2 


25 


55 


,31: 


39 


105 


::;-55:. 


56 


174 ,.;:89 


74 


299 Hl34i 


103 


419 


1.192: 


128 


558 260 


156 


718 h^39 


187 


900 K432 




3 


26 


59 


: 3& 


41 


115 


: 64 


57 


189 _ 102 


76 


319 [153: 


105 


448 


;215 


131 


597 292 


159 


760 |; 382. 


190 


960 \ 48e; 


20 


1 


24 


52 


2^ 


37 


102 


' 46: 


53 


172 'i77 


71 


313 ill9 


98 


437 


';J:73 


123 


584 2m 


150 


752 : 312 


180 


943 : :397 




2 


25 


58 


■■-m\ 


39 


114 


::>'56; 


55 


190 :;9i 


73 


335 ri38: 


101 


467 


-iW9 ■ 


126 


625 270 


153 


805 rB54 


184 


1011 ;'452 




3 


26 


63 


35 


40 


123 


;-> 65; 


57 


204 ,104 


75 


353 1157^ 


104 


493 


■222 


129 


661 301, 


156 


851 -.^sie: 


187 


1067 1 ,505 


30 


1 


24 


54 


25 


37 


111 


";■ 48. 


52 


192 82 


69 


357 1127' 


96 


504 


;i87: 


119 


680 255 


145 


883 L337: 


175 


1115 ; 432 




2 


25 


60 


^^ 32 


38 


122 


s:58; 


54 


208 '';'95' 


72 


376 n^- 


99 


531 


^'209' 


122 


715 ' 287 


149 


928 ';378* 


179 


1171 i ^484 




3 


26 


64 


; 36 


40 


131 


;': : ^l 


56 


221 Jp7 


74 


392 j:163^ 


101 


554 


-233. 


125 


746 317 


152 


968 ?.418. 


182 


1220 1 ,535 


50 


1 


23 


51 


25- 


36 


116 


-^:5T 


51 


209 ; 89 


67 


405 1 1434 


92 


582 


:213; 


115 


798 ,294 


140 


1049 ■;.392: 


168 


1334 ■:,506 




2 


24 


59 


32 


37 


127 


"■"- 61 


53 


225 102 


70 


421 1 161; 


95 


604 


■235 


118 


827 326 


143 


1085 I 433 


172 


1379 \ 558 




3 


26 


64 


-.■■3^.; 


39 


135 


11; .69; 


55 


237 ;;l-15: 


72 


435 :;18tf 


98 


624 


^:260 


121 


854 357^ 


147 


1118 iC=474: 


176 


1421 'vjeii; 


100 


1 


23 


46 


. :2i 


35 


108 


\:: 5a 


49 


208 ,:-92, 


65 


428 il55i 


88 


640 


'-m 


109 


907 , 334: 


134 


1222 r454; 


161 


1589 I; 596 




2 


24 


53 


31 


37 


120 


60 


51 


224 105 


67 


444 ! 174: 


92 


660 


;260 


113 


933 368 


138 


1253 - 497 


165 


1626 ' 651 




3 


25 


59 


'.•.35- 


38 


130 


vi^m. 


53 


237 ' ;118 


69 


458 1193: 


94 


679 


=-'285-; 


116 


956 '399 


141 


1282 ;'-54b; 


169 


1661 1-705, 



Common Vent Capacity 

















Minimum Internal Area of Masonry Chimney Flue (in 


') 










12 


19 


28 


38 


50 


63 


78 


113 


Vent 














Combined A 


ppliance Input Rating in Thousands of Btu per Hour 








Height 
H 
(ft) 


FAN FAN 
hFAN+NAT 


-NAT, 
+NAT 


FAN 

hFAN-t 


FAN ::NAT 
NAT+NAT 


FAN 
hFANh 


FAN j;nat; 

hNAT-i-NAT 


FAN 
^FAN^ 


FAN '-NATi 
-NAT+NAT.: 


FAN FAN ,NAT- 
hFAN+NAT+NAT 


FAN 
hFAN-t 


FAN ;NAT 
NAT+NAT 


FAN 
hFANh 


FAN fNAT 
hNAT+NAT 


FAN 
hFAN 


FAN ; 

+FAN ' 


NAT'; 

+NAT: 


6 


NA 


74 


''■'i25 


NA 


119 ^ ' '^6 


NA 


178 ; 71 


NA 


257 f'.'lOS 


NA 351 :.*143 


NA 


458 ; 188 


NA 


582 : 246 


1041 


853 ' 


.NA 


8 


NA 


80 


■'^iM 


NA 


130 ! : ,53^ 


NA 


193 r :82,: 


NA 


279 ^; 119:: 


NA 384 ::i63: 


NA 


501 : 218 


724 


636:^^278 


1144 


937 ■ 


'-'408, 


10 


NA 


84 


:. "31 


NA 


138 ! 56 


NA 


207 ; 90 


NA 


299 i; 131: 


NA 409 ; 177: 


606 


538 1 236 


776 


686 \ 302, 


1226 


1010 1 


,454 


15 


NA 


NA 


■■■':^36= 


NA 


152 prfer 


NA 


233 f 10'6; 


NA 


334 ::152: 


523 467 : .212" 


682 


611 '283 


874 


781 I 365 


1374 


1156 1 


54'6 


20 


NA 


NA 


fH'l^l' 


NA 


NA ;^-.75' 


NA 


250 ' i2'2"" 


NA 


368 :;^i72: 


565 508 '243- 


742 


668 ;'"3'25 


955 


858 ^ 'W 


1513 


1286^ 


'^648 


30 


NA 


NA 


.:..:NA 


NA 


NA !, NA 


NA 


270 '. 137 


NA 


404 P; 198; 


615 564 ;278. 


816 


747 : ;38] 


1062 


969 \ 496, 


1702 


1473 \ 


. ::;7.49' 


50 


NA 


NA 


' '^NA-' 


NA 


NA ''■"NA 


NA 


NAi^m' 


NA 


NA ',' -NA": 


NA 620 "'528 


879 


831 : 461 


1165 


1089 ! 6'06 


1905 


1692 : 


922 


100 


NA 


NA 


,.,\:na; 


NA 


NA .':.NA: 


NA 


NA i: NA 


NA 


NA ;;i:NA: 


NA NA , '348: 


NA 


NA j 499, 


NA 


NA ;, -669: 


2053 


1921 : 


1058 



2002 Edition 



ANSIZ223.1-101 



SIZING OF CATEGORY I VENTING SYSTEMS 



54-101 



Table 13.9 Masoniy Chimney 





Number of Appliances: 


Two or More 




Appliance Type: 


Category I 




Appliance Vent Connection: 


Single Wall Metal Connector 



Vent Connector Capacity 





















Single-Wall Metal Vent Connector Diameter - 


-D(m.) 
















3 


4 


5 


6 


7 


8 


9 


ID 


Vent C 
















Appliance Input Rating Limits 


in Thousands of Btu per Hour 














Height 
H 

(ft) 


Rise 
R 

(ft) 


FAN 


NAT. 
Max 


FAN 


NAT 
Max. 


FAN ^nat; 


FAN ;NAT. 


FAN ;NAT. 


FAN |NAT. 


FAN 


NAT 
Mas. 


FAN 


NAT 


Min 


Max 


Min 


Max 


Min 


Max :.Max- 


Min Max iMax 


Min 


Max ': Max 


Min 


Max : Max 


Min 


Max 


Min 


Max 


Max 


6 


1 


NA 


NA 


::2i 


NA 


NA 


39 


NA 


NA L 66: 


179 191 I.TOO. 


231 


271 ; 140. 


292 


366 h 200 


362 


474 


252 


499 


594 


316 




2 


NA 


NA 


28 


NA 


NA 


52 


NA 


NA : 84 


186 227 ; i'23 


239 


321 '■ 172 


301 


432 : 231 


373 


557 


299 


509 


696 


376 




3 


NA 


NA 


.;;;34^ 


NA 


NA^ 


'^^61 


134 


153 :i- 97; 


193 258 ».:142 


247 


365 ;;202i 


309 


491 h269; 


381 


634 


:348 


519 


793 


437 


8 


1 


NA 


NA 


;;.21t 


NA 


NA 


.;:40? 


NA 


Na': .68: 


195 208 1 .103 


250 


298 j 14^ 


313 


407 ir207. 


387 


530 


263 


529 


672 


331 




2 


NA 


NA 


•=28 


NA 


NA 


52 


137 


139; 85 


202 240 ■: 125 


258 


343 : 177 


323 


465: 238 


397 


607 


309 


540 


766 


391 




3 


NA 


NA 


vi^^^ 


NA 


NA 


'62 


143 


156 J; 98: 


210 264 :' tY45 


266 


376 = 205^ 


332 


509 ^274? 


407 


663 


356 


551 


838 


450 


10 


1 


NA 


NA 


';-2:2- 


NA 


NA 


"41 


130 


151 =- # 


202 225 f 406. 


267 


316 -151 


333 


434 ^n213 


410 


571 


273 


558 


727 


343 




2 


NA 


NA 


;;29 


NA 


NA 


53 


136 


150 r 86. 


210 255 128 


276 


358 ; 181 


343 


489 ■ . 244 


420 


640 


317 


569 


813 


403 




3 


NA 


NA 


'.i'^'^- 


97 


102 


"62 


143 


166 y 99= 


217 277 147- 


284 


389 r 20T 


352 


530 .;*;279 


430 


694 


363 


580 


880 


459 


15 


1 


NA 


NA 


Hlks- 


NA 


NA 


'■■^43 = 


129 


151 r 73- 


199 271 -'li'2^ 


268 


376 : 161 


349 


502 P225: 


445 


646 


291 


623 


808 


366 




2 


NA 


NA 


-30: 


92 


103 ; 


:54. 


135 


170 • .88. 


207 295 , 132 


277 


411 189 


359 


548 :; 256 


456 


706 


334 


634 


884 


424 




3 


NA 


NA 


=:34 


96 


112 i 


63 


141 


185 r 161 


215 315 i 151 


286 


439 r 213 


368 


586 :5; 289 


466 


755 


378 


646 


945 


479 


20 


1 


NA 


NA 


■'■ 23' 


87 


99 


■'45 


128 


167 f'li 


197 303 "'lir 


265 


425 ; 169 


345 


569? 235 


439 


734 


306 


614 


921 


387 




2 


NA 


NA 


^•^30 ; 


91 


111 


..-55. 


134 


185 '.90: 


205 325 .,.136; 


274 


455 , 195 


355 


610 ::.266 


450 


787 


348 


627 


986 


443 




3 


NA 


NA 


35 


96 


119 


64 


140 


199 ;: 103 


213 343 154 


282 


481 : 219 


365 


644 : 298 


461 


831 


391 


639 


1042 


496 


30 


1 


NA 


NA 


::^24- 


86 


108 


"i47 


126 


187 fso' 


193 347 124 


259 


492 ' m 


338 


665 r 250 


430 


864 


330 


600 


1089 


421 




2 


NA 


NA 


i^'Sh 


91 


119: 


..■^57- 


132 


203;; 93 = 


201 366 i:jl42; 


269 


518 ,:205: 


348 


699 i;282. 


442 


908 


372 


613 


1145 


473 




3 


NA 


NA 


35 


95 


127 


.65 


138 


216 { 105 


209 381 160 


277 


540 : 229 


358 


729 :, 312 


452 


946 


412 


626 


1193 


524 


50 


1 


NA 


NA 


'';'24" 


85 


113 


50 


124 


204 j. 87- 


188 392 ; 139 


252 


567; 208 


328 


778 ;' 287 


417 


1022 


383 


582 


1302 


492 




2 


NA 


NA 


':f3i:' 


89 


123 


' m 


130 


218 ":i06: 


196 408 ; ass; 


262 


588 - 230 


339 


806 1^320- 


429 


1058 


425 


596 


1346 


545 




3 


NA 


NA 


35^ 


94 


131 


68 


136 


231 t 112; 


205 422 : :li76 


271 


607 i 255 


349 


831 I 351 


440 


1090 


466 


610 


1386 


597 


100 


1 


NA 


na' 


;.23. 


84 


104' 


;49 


122 


200 i 89, 


182 410 : 151 


243 


617 i 232 


315 


875 ■ 328 


402 


1181 


444 


560 


1537 


580 




2 


NA 


NA 


■"i30- 


88 


115 ; 


-^59 


127 


215 j 162- 


190 425 '■169' 


253 


636 ' 254 


326 


899 i' 361 


415 


1210 


488 


575 


1570 


634 




3 


NA 


NA 


X34: 


93 


124 : 


. ,67^ 


133 


228 tll5 


199 438 ; 188, 


262 


654 i 279 


337 


921 ■ 392 


427 


1238 


529 


589 


1604 


687 



Common Vent Capacity 

















Minimum Internal Area of 


Masonry Chimney Flue (in 


.') 










12 


19 


28 


38 


50 


63 


78 


113 


Vent 














Combined Appliance Input Rat 


ing in Thousands of Btu per Hour 








Height 
H 


FAN 


FAN 


:;NAT:^ 


FAN 


FAN JNAT; 


FAN 


FAN IrSFAT,: 


FAN 


FAN NAT 


FAN FAN :NAT 


FAN 


FAN [NAT 


FAN 


FAN ^NAT 


FAN 


FAN 


NAT 


(ft) 


fFAN- 


hNAT 


fNAT- 


I-FAN4 


NAT-i-NAt' 


i-FANh 


hNAT+NAT 


i-FAN+NAT+NAT 


hFAN+NAT+NAT 


hFAN4 


NAT -fNAT 


hFANh 


hNAT+NAT 


hFAN +FAN 


+NAT 


6 


NA 


NA 


P- '2^: 


NA 


118 ''v'ks'. 


NA 


176 r"-7i' 


NA 


255 r iis^ 


NA 348 ~ l4V 


NA 


455 ■ 187 


NA 


579 f 245' 


NA 


846 


NA 


8 


NA 


NA 


v}^M 


NA 


128 I:r52-; 


NA 


190 -jfSl 


NA 


276 ,.1^8 


NA 380 |. 162 


NA 


497 1 217 


NA 


633 : 277. 


1136 


928 


405 


10 


NA 


NA 


1'' 3i:. 


NA 


136 r • 56 


NA 


205 \ * 89 


NA 


295 : 129 


NA 405 ; 175 


NA 


532 i 234 


771 


680 ; 300 


1216 


1000 


450 


15 


NA 


NA 


^J(--36/ 


NA 


NA h:..;66r 


NA 


230 ; 105 


NA 


335 ; ;150: 


NA 400 ■ 210 


677 


602 1' 280. 


866 


772 t .360 


1359 


1139 


540 


20 


NA 


NA 


:;: NAJ 


NA 


NA ! ■ : .74 


NA 


247 j 120 


NA 


362 1:70 


NA 503 I 240 


765 


661 r 321 


947 


849 : 415 


1495 


1264 


640 


30 


NA 


NA 


';' NAf 


NA 


NA :nNA'- 


NA 


NAbll35 


NA 


398 i 195* 


NA 558 i 275 


808 


739 s 377 


1052 


957 ;• 490- 


1682 


1447 


740 


50 


NA 


NA 


:..NA 


NA 


NA ; ;.NA. 


NA 


NA ! . NA 


NA 


NA, NA 


NA 612 '■ 325 


NA 


821 ; 456 


1152 


1076 ; 600 


1879 


1672 


910 


100 


NA 


NA 


■■' NA. 


NA 


NA i:;NA= 


NA 


NA;; = m' 


NA 


NAf?.I^JA• 


NA NA ;■ NA 


NA 


NAr494 


NA 


NA i' 663 


2006 


1885 


1046 



For SI units, 1 in. = 25.4 mm, 1 in.^ = 645 mm^, 1 ft = 0.305 m, 1000 Btu per hr = 0.293 kW. 



2002 Edition 



54-102 



NATIONAL FUEL GAS CODE 



ANSIZ223.1-102 



Table 13.10 Single-Wall Metal Pipe or Type B Asbestos Cement Vent 



Number of Appliances: 


Two or More 


Appliance Type: 


Draft Hood-Equipped 


Appliance Vent Connection: 


Direct to Pipe or Vent 



Vent Connector Capacity 












Connector 

Rise 

R 

(ft) 


Vent Connector Diameter — D (in.) 


Total Vent Height 
H 

(ft) 


3 


4 5 6 7 


8 


Maximum Appliance Input Rating in Thousands of Btu per Hoiu- 



6-8 



30 
and up 



21 
28 
34 



40 
53 
61 



102 
124 
147 



25 
31 
36 



49 
58 



146 
178 
204 



205 
235 
275 





1 


23 


44 


77 


117 


179 


240 


15 


2 


30 


56 


92 


134 


194 


265 




3 


35 


64 


102 


155 


216 


298 



84 


129 


190 


270 


97 


145 


211 


295 


07 


164 


232 


321 



Common Vent Capacity 



Total Vent Height 

H 

(ft) 


6 


48 


8 


55 


10 


59 


15 


71 


20 


80 


30 


NA 


50 


NA 



Common Vent Diameter — D (in.) 



Combined Appliance Input Rating in Thousands of 
Btu per Hour 



10 



12 



78 
89 
95 
115 
129 
147 
NA 



111 
128 
136 
168 
186 
215 
NA 



155 


205 


320 


NA 


175 


234 


365 


505 


190 


250 


395 


560 


228 


305 


480 


690 


260 


340 


550 


790 


300 


400 


650 


940 


360 


490 


810 


1190 



Note: See Figure G.l(f), Figure G.6 and Section 13.2. 

For 81 units, 1 in. = 25.4 mm, 1 in.'^ = 645 mm^, 1 ft = 0.305 m, 1000 Btu per hr = 0.293 kW. 



2002 Edition 



ANSIZ223.1-103 



SIZING OF CATEGORY I VENTING SYSTEMS 



54-103 



Table 13.11 Exterior Masonry Chimney 





Special Use: 




Minimum Allowable Input Rating of Space-Heating Appli 


ance in Thousands of Btu per Hour 




Number of Appliances: 


Single 


Appliance Type: 


NAT 


Appliance Vent Connection: 




Type B Double Wall Connecto 


r 




Vent Height 
H 

(ft) 


Internal Area of Chimney (in.^) 


12 


19 


28 


38 


50 




63 


78 


113 


37°F or greater 
6 








Local 99% winter design temperature: 37°F or greater 









8 






























10 






























15 




NA 

























20 




NA 


NA 


123 


190 


249 




184 








30 




NA 


NA 


NA 


NA 


NA 




393 


334 





50 




NA 


NA 


NA 


NA 


NA 




NA 


NA 


579 


27°F to 36°F 
6 








Local 99% winter design temperature: 27°F to 
68 116 156 


36°F 


180 


212 


266 


8 










82 


127 


167 




187 


214 


263 


10 







51 


97 


141 


183 




201 


225 


265 


15 




NA 


NA 


NA 


NA 


233 




253 


274 


305 


20 




NA 


NA 


NA 


NA 


NA 




307 


330 


362 


30 




NA 


NA 


NA 


NA 


NA 




419 


445 


485 


50 




NA 


NA 


NA 


NA 


NA 




NA 


NA 


763 


17°F to 26°F 
6 


NA 


NA 


Local 99% winter des 

NA NA 


gn temperature: 17°F to 

NA 


26°F 


215 


259 


349 


8 




NA 


NA 


NA 


NA 


197 




226 


264 


352 


10 




NA 


NA 


NA 


NA 


214 




245 


278 


358 


15 




NA 


NA 


NA 


NA 


NA 




296 


331 


398 


20 




NA 


NA 


NA 


NA 


NA 




352 


387 


457 


30 




NA 


NA 


NA 


NA 


NA 




NA 


507 


581 


50 




NA 


NA 


NA 


NA 


NA 




NA 


NA 


NA 


5°F to 16°F 
6 


NA 


NA 


Local 99% winter des 

NA NA 


ign temperature: 5°F to 

NA 


16°F 


NA 


NA 


416 


8 




NA 


NA 


NA 


NA 


NA 




NA 


312 


423 


10 




NA 


NA 


NA 


NA 


NA 




289 


331 


430 


15 




NA 


NA 


NA 


NA 


NA 




NA 


393 


485 


20 




NA 


NA 


NA 


NA 


NA 




NA 


450 


547 


30 




NA 


NA 


NA 


NA 


NA 




NA 


NA 


682 


50 




NA 


NA 


NA 


NA 


NA 




NA 


NA 


972 


-10°F to 
6 


4°F 


NA 


NA 


Local 99% winter des 

NA NA 


gn temperature: -10°F to 4°F 

NA 


NA 


NA 


484 


8 




NA 


NA 


NA 


NA 


NA 




NA 


NA 


494 


10 




NA 


NA 


NA 


NA 


NA 




NA 


NA 


513 


15 




NA 


NA 


NA 


NA 


NA 




NA 


NA 


586 


20 




NA 


NA 


NA 


NA 


NA 




NA 


NA 


650 


30 




NA 


NA 


NA 


NA 


NA 




NA 


NA 


805 


50 




NA 


NA 


NA 


NA 


NA 




NA 


NA 


1003 


-11°F or lower 






Local 99% winter design temperature: -11°F or lowf 
Not recommended for any vent configurations 


r 







Note: See Figure G.19 for a map showing local 99 percent winter design temperatures in the United States. 
For SI units, 1 in. = 25.4 mm, 1 in.^ = 645 mm^, 1 ft = 0.305 m, 1000 Btu per hr = 0.293 kW. 



2002 Edition 



54-104 



NATIONAL FUEL GAS CODE 



ANSIZ223.1-104 



Table 1 3 . 1 2 (a) Exterior Masonry Chimney 



Special Use: 






Combined i^pliance Maximum 


Input Rating 


in Thousands of Btu per Hour 






Number of Appliances: 








Two or 


More 






Appliance Type: 








NAT + 


NAT 






Appliance Vent Connection: 






Type 


B Double Wall Connector 






Vent 
Height 








Internal Area of Chimney (in 


.') 










H 
























(ft) 




12 


19 


28 


38 




50 




63 


78 


113 


6 




25 


46 


71 


103 




143 




188 


246 


NA 


8 




28 


53 


82 


119 




163 




218 


278 


408 


10 




31 


56 


90 


131 




177 




236 


302 


454 


15 




NA 


67 


106 


152 




212 




283 


365 


546 


20 




NA 


NA 


NA 


NA 




NA 




325 


419 


648 


30 




NA 


NA 


NA 


NA 




NA 




NA 


496 


749 


50 




NA 


NA 


NA 


NA 




NA 




NA 


NA 


922 


100 




NA 


NA 


NA 


NA 




NA 




NA 


NA 


NA 



For SI units, 1 in. = 25.4 mm, 1 in.^ = 645 mm^, 1 ft = 0.305 m, 1000 Btu per hr = 0.293 kW. 



13.2.4 Vent Connector Manifolds. Where the vent connectors 
are combined prior to entering the vertical portion of the 
common vent to form a common vent manifold, the size of the 
common vent manifold and the common vent shall be deter- 
mined by applying a 10 percent reduction (.90 x maximum 
common vent capacity) to the Common Vent Capacity part of 
the common vent tables. The length of the common vent 
manifold (LM) shall not exceed 18 in. /in. (18 mm/mm) of 
common vent diameter (D). 

13.2.5 Vent Offsets. Where the common vertical vent is offset, 
the maximum capacity of the common vent shall be reduced 
in accordance with 13.2.6 and the horizontal length of the 
common vent offset shall not exceed 18 in. /in. (18 mm/mm) 
of common vent diameter (D). 

13.2.6 Elbows in Vents. For each elbow up to and including 45 
degrees in the common vent, the maximum common vent 
capacity listed in the venting tables shall be reduced by 5 per- 
cent. For each elbow greater than 45 degrees up to and includ- 
ing 90 degrees, the maximum common vent capacity listed in 
the venting tables shall be reduced by 10 percent. 

13.2.7 Elbows in Connectors. The vent connector capacities 
listed in the common vent sizing tables include allowance for 
two 90 degree elbows. For each additional elbow up to and 
including 45 degrees, the maximum vent connector capacit)' 
listed in the venting tables shall be reduced by 5 percent. For 
each elbow greater than 45 degrees up to and including 90 
degrees, the maximum vent connector capacity listed in the 
venting tables shall be reduced by 10 percent. 

13.2.8 Common Vent Minimum Size. The cross-sectional area 
of the common vent shall be equal to or greater than the cross- 
sectional area of the largest connector. 

13.2.9 Tee and M^e Sizing. At the point where tee or wye fit- 
tings connect to a common vent, the opening size of the fitting 
shall be equal to the size of the common vent. Such fittings 
shall not be prohibited from having reduced size openings at 
the point of connection of appliance vent connectors. 

13.2.10 High Altitude Installations Sea level input ratings 
shall be used when determining maximum capacity for high- 
altitude installation. Actual input (derated for altitude) shall 



be used for determining minimum capacity for high-altitude 
installation. 

13.2.11 Connector Rise. The connector rise (R) for each ap- 
pliance connector shall be measured from the draft hood out- 
let or flue collar to the centerline where the vent gas streams 
come together. 

13.2.12 Vent Height. For multiple units of gas utilization 
equipment all located on one floor, available total height (H) 
shall be measured from the highest draft hood outlet or flue 
collar up to the level of the outlet of the common vent. 

13.2.13 Multistory Vent Height. For multistory installations, 
available total height (H) for each segment of the system shall 
be the vertical distance between the highest draft hood oudet 
or flue collar entering that segment and the centerline of the 
next higher interconnection tee. (See Figure G.13.) 

13.2.14 Multistory Lowest Vent and Vent Connector Sizing. 

The size of the lowest connector and of the vertical vent leading 
to the lowest interconnection of a multistory system shall be in 
accordance vwth Table 13.1 or Table 13.2 for available total 
height (H) up to the lowest interconnection. (See Figure G.14.) 

13.2.15 Multistory B Vents Required. Where used in multi- 
story systems, vertical common vents shall be Type B double- 
wall and shall be installed with a listed vent cap. 

13.2.16 Multistory Vent Offsets and Capacity. Offsets in mul- 
tistory common vent systems shall be limited to a single offset 
in each system, and systems with an offset shall comply with all 
of the following: 

( 1 ) The offset angle shall not exceed 45 degrees from vertical. 

(2) The horizontal length of the offset shall not exceed 
18 in. /in. (18 mm/mm) of common vent diameter of the 
segment in which the offset is located. 

(3) For the segment of the common vertical vent containing 
the offset, the common vent capacity listed in the com- 
mon venting tables shall be reduced by 20 percent (0.80 
X maximum common vent capacity). 

(4) A multistory common vent shall not be reduced in size 
above the offset. 



2002 Edition 



ANSIZ223.1-105 



SIZING OF CATEGORY I VENTING SYSTEMS 



54-105 



Table 13.12(b) Exterior Masonry Chimney 



Special Use: 




Minimum Allowable Input Rating of Space- 


Heating AppUance in Thousands of Btu per Hour 




Number of Appliances: 


Two or More 


Appliance Type: 


NAT + NAT 


Appliance Vent Connection: 


Type B Double Wall Connector 


Vent 
Height 


Internal Area of Chimney (in.^) 


H 

(ft) 


12 


19 


28 


38 




50 


63 


78 


113 


37°F or greater 
6 








Local 99% winter design temperature: 
37°F or greater 









NA 


8 




























10 




























15 


NA 

























20 


NA 


NA 


NA 


NA 




NA 


184 








30 


NA 


NA 


NA 


NA 




NA 


393 


334 





50 


NA 


NA 


NA 


NA 




NA 


NA 


NA 


579 


100 


NA 


NA 


NA 


NA 




NA 


NA 


NA 


NA 


27°F to 36°F 






Local 99% winter 

27°F 


design temperature: 
to 36°F 








6 








68 


NA 




NA 


180 


212 


NA 


8 








82 


NA 




NA 


187 


214 


263 


10 





51 


NA 


NA 




NA 


201 


225 


265 


15 


NA 


NA 


NA 


NA 




NA 


253 


274 


305 


20 


NA 


NA 


NA 


NA 




NA 


307 


330 


362 


30 


NA 


NA 


NA 


NA 




NA 


NA 


445 


485 


50 


NA 


NA 


NA 


NA 




NA 


NA 


NA 


763 


100 


NA 


NA 


NA 


NA 




NA 


NA 


NA 


NA 


17°F to 26°F 






Local 99% winter 
17°F 


design temperature: 
to 26°F 








6 


NA 


NA 


NA 


NA 




NA 


NA 


NA 


NA 


8 


NA 


NA 


NA 


NA 




NA 


NA 


264 


352 


10 


NA 


NA 


NA 


NA 




NA 


NA 


278 


358 


15 


NA 


NA 


NA 


NA 




NA 


NA 


331 


398 


20 


NA 


NA 


NA 


NA 




NA 


NA 


387 


457 


30 


NA 


NA 


NA 


NA 




NA 


NA 


NA 


581 


50 


NA 


NA 


NA 


NA 




NA 


NA 


NA 


862 


100 


NA 


NA 


NA 


NA 




NA 


NA 


NA 


NA 


5°Ftol6°F 






Local 99% winter 
5°F 


design temperature: 
to 16°F 








6 


NA 


NA 


NA 


NA 




NA 


NA 


NA 


NA 


8 


NA 


NA 


NA 


NA 




NA 


NA 


NA 


NA 


10 


NA 


NA 


NA 


NA 




NA 


NA 


NA 


430 


15 


NA 


NA 


NA 


NA 




NA 


NA 


NA 


485 


20 


NA 


NA 


NA 


NA 




NA 


NA 


NA 


547 


30 


NA 


NA 


NA 


NA 




NA 


NA 


NA 


682 


50 


NA 


NA 


NA 


NA 




NA 


NA 


NA 


NA 


100 


NA 


NA 


NA 


NA 




NA 


NA 


NA 


NA 


4°F or lower 






Local 99% winter design temperature: 
4°F or lower 














Not recommended for any vent configurations 







Note: See Figure G.19 for a map showing local 99 percent winter design temperatures in the United States. 
For SI units, 1 in. = 25.4 mm, 1 in.^ = 645 mm^, 1 ft = 0.305 m, 1000 Btu per hr = 0.293 kW. 



13.2.17 Vertical Vent Size Limitation. Where two or more ap- 
pliances are connected to a vertical vent or chimney, the flow 
area of the largest section of vertical vent or chimney shall not 
exceed seven times the smallest listed appliance categorized 
vent areas, flue collar area, or draft hood outlet area unless 
designed in accordance with approved engineering methods. 



13.2.18 Two Stage/Modulating Appliances. For appliances 
with more than one input rate, the minimum vent connector 
capacity (FAN Min) determined from the tables shall be less than 
the lowest appliance input rating, and the maximum vent con- 
nector capacity (FAN Max or NAT Max) determined from the 
tables shall be greater than the highest appliance input rating. 



2002 Edition 



54-106 



NATIONAL FUEL GAS CODE 



ANSIZ223.1-106 



Table 1 3. 1 3 (a) Exterior Masonry Chimney 



Special Use: 




Combined AppUance Maximum 


Input Rating in Thousands of Btu per Hour 






Number of Appliances: 


Two or More 


Appliance Type: 


FAN + NAT 


Appliance Vent Connection: 




Type 


B Double Wall Connector 






Vent 
Height 


Internal Area of Chimney (in.^) 


H 

(ft) 


12 


19 


28 


38 


50 


63 78 




113 


6 


74 


119 


178 


257 


351 


458 


582 


853 


8 


80 


130 


193 


279 


384 


501 


636 


937 


10 


84 


138 


207 


299 


409 


538 


686 


1010 


15 


NA 


152 


233 


334 


467 


611 


781 


1156 


20 


NA 


NA 


250 


368 


508 


668 


858 


1286 


30 


NA 


NA 


NA 


404 


564 


747 


969 


1473 


50 


NA 


NA 


NA 


NA 


NA 


831 


1089 


1692 


100 


NA 


NA 


NA 


NA 


NA 


NA 


NA 


1921 



For SI units, 1 in. = 25.4 mm, 1 in.'^ = 645 mm'^ 1 ft = 0.305 m, 1000 Btu per hr = 0.293 kW. 



13.2.19* Corrugated Chimney Liners. Listed, corrugated me- 
tallic chimney liner systems in masonry chimneys shall be sized 
by using Table 13.6 or Table 13.7 for Type B vents, with the 
maximum capacity reduced by 20 percent (0.80 x maximum 
capacity) and the minimum capacity as shown in Table 13.6 or 
Table 13.7. Corrugated metallic liner systems installed with 
bends or offsets shall have their maximum capacity further 
reduced in accordance with 13.2.5 and 13.2.6. The 20 percent 
reduction for corrugated metallic chimney liner systems in- 
cludes an allowance for one long radius 90-degree turn at the 
bottom of the liner. 

13.2.20 Exterior Chimneys and Vents. Table 13.6 through 
Table 13.10 shall be used for chimneys and vents not exposed 
to the outdoors below the roof line. A Type B vent or listed 
chimney lining system passing through an unused masonry 
chimney flue shall not be considered to be exposed to the 
outdoors. Table 13.12(a), Table 13.12(b), Table 13.13(a), and 
Table 13.13(b) shall be used for clay-tile-lined exterior ma- 
sonry chimneys, provided all the following conditions are met: 

(1) Vent connector is Type B double-wall. 



(2) 
(3) 



(4) 



(5) 



At least one appliance is draft hood-equipped. 

The combined appliance input rating is less than the 

maximum capacity given by Table 13.12(a) (for 

NAT+NAT) or Table 13.13(a) (for FAN+NAT) . 

The input rating of each space-heating appliance is 

greater than the minimum input rating given by Table 

13.12(b) (for NAT+NAT) or Table 13.13(b) (for 

FAN+NAT). 

The vent connector sizing is in accordance with Table 

13.8. 



Where these conditions cannot be met, an alternative venting 
design shall be used, such as a listed chimney lining system. 

Exception: Vents serving listed appliances installed in accordance 
with the appliance manufacturer's instructions and the terms of the 
listing. 

13.2.21 Vent Connector Upsizing. Vent connectors shall not 
be increased more than two sizes greater than the listed appli- 
ance categorized vent diameter, flue collar diameter, or draft 
hood outlet diameter. Vent connectors for draft hood- 
equipped appliances shall not be smaller than the draft hood 



outlet diameter. Where a vent connector size(s) determined 
from the tables for a fan-assisted appliance (s) is smaller than 
the flue collar diameter, the use of the smaller size(s) shall be 
permitted provided that the installation complies with all of 
the following conditions: 

(1) Vent connectors for fan-assisted appliance flue collars 
12 in. (300 mm) in diameter or smaller are not reduced 
by more than one table size [e.g., 12 in. to 10 in. (300 mm 
to 250 mm) is a one-size reduction] and those larger than 
12 in. (300 mm) in diameter are not reduced more than 
two table sizes [e.g., 24 in. to 20 in. (610 mm to 510 mm) is 
a two-size reduction]. 

(2) The fan-assisted appliance (s) is common vented with a 
draft hood-equipped appliance (s). 

(3) The vent connector has a smooth interior wall. 

13.2.22 Mvdtiple Vent and Connector Sizes. All combination 
of pipe sizes, single-wall, and double-wall metal pipe shall be 
allowed within any connector run(s) or within the common 
vent, provided ALL of the appropriate tables permit ALL of 
the desired sizes and types of pipe, as if they were used for the 
entire length of the subject connector or vent. Where single- 
wall and Type B double-wall metal pipes are used for vent con- 
nectors within the same venting system, the common vent 
must be sized using Table 13.7 or Table 13.9 as appropriate. 

13.2.23 Multiple Vent and Connector Sizes Permitted. Where 
a table permits more than one diameter of pipe to be used for 
a connector or vent, all the permitted sizes shall be permitted 
to be used. 

13.2.24 Interpolation. Interpolation shall be permitted in cal- 
culating capacities for vent dimensions that fall between table 
entries. (See Example 3, Annex G.) 

13.2.25 Extrapolation. Extrapolation beyond the table entries 
shall not be permitted. 

13.2.26 Sizing Vents not Covered by Tables. For vent heights 
lower than 6 ft and higher than shovm in the tables, engineer- 
ing methods shall be used to calculate vent capacities. 



2002 Edition 



ANSIZ223.1-107 



SIZING OF CATEGORY I VENTING SYSTEMS 



54-107 



Table 1 3. 1 3 (b) Exterior Masonry Chinmey 





Special Use: 




Minimimi Allowable Input Rating of Space-Heating Appliance in Thousands of Btu per Hour 




Number of Appliances: 


Two or More 


Appliance Type: 


NAT + NAT 


Appliance Vent Connection: 


Type B Double Wall Connector 


Vent 
Height 




Internal Area of Chinmey (in.^) 


H 

(ft) 


12 


19 


28 


38 




50 


63 


78 


113 


37°F or greater 
6 








Local 99% winter design temperature: 
37°F or greater 












8 






























10 






























15 




NA 

























20 




NA 


NA 


123 


190 




249 


184 








30 




NA 


NA 


NA 


334 




398 


393 


334 





50 




NA 


NA 


NA 


NA 




NA 


714 


707 


579 


100 




NA 


NA 


NA 


NA 




NA 


NA 


NA 


1600 


27°F to 


36°F 






Local 99% winter 

27°F 


design temperature: 
to 36°F 








6 










68 


116 




156 


180 


212 


266 


8 










82 


127 




167 


187 


214 


263 


10 







51 


97 


141 




183 


210 


225 


265 


15 




NA 


111 


142 


183 




233 


253 


274 


305 


20 




NA 


NA 


187 


230 




284 


307 


330 


362 


30 




NA 


NA 


NA 


330 




319 


419 


445 


485 


50 




NA 


NA 


NA 


NA 




NA 


672 


705 


763 


100 




NA 


NA 


NA 


NA 




NA 


NA 


NA 


1554 


17°Fto 


26°F 






Local 99% winter 
17°F 


design temperature: 
to 26°F 








6 







55 


99 


141 




182 


215 


259 


349 


8 




52 


74 


111 


154 




197 


226 


264 


352 


10 




NA 


90 


125 


169 




214 


245 


278 


358 


15 




NA 


NA 


167 


212 




263 


296 


331 


398 


20 




NA 


NA 


212 


258 




316 


352 


387 


457 


30 




NA 


NA 


NA 


362 




429 


470 


507 


581 


50 




NA 


NA 


NA 


NA 




NA 


723 


766 


862 


100 




NA 


NA 


NA 


NA 




NA 


NA 


NA 


1669 


5°Fto 


16°F 






Local 99% winter design temperature: 
5°F to 16°F 








6 




NA 


78 


121 


166 




214 


252 


301 


416 


8 




NA 


94 


135 


182 




230 


269 


312 


423 


10 




NA 


111 


149 


198 




250 


289 


331 


430 


15 




NA 


NA 


193 


247 




305 


346 


393 


485 


20 




NA 


NA 


NA 


293 




360 


408 


450 


547 


30 




NA 


NA 


NA 


377 




450 


531 


580 


682 


50 




NA 


NA 


NA 


NA 




NA 


797 


853 


972 


100 




NA 


NA 


NA 


NA 




NA 


NA 


NA 


1833 


-10°F to 4°F 






Local 99% winter design temperature: 
-10°F to 4°F 








6 




NA 


NA 


145 


196 




249 


296 


349 


484 


8 




NA 


NA 


159 


213 




269 


320 


371 


494 


10 




NA 


NA 


175 


231 




292 


339 


397 


513 


15 




NA 


NA 


NA 


283 




351 


404 


457 


586 


20 




NA 


NA 


NA 


333 




408 


468 


528 


650 


30 




NA 


NA 


NA 


NA 




NA 


603 


667 


805 


50 




NA 


NA 


NA 


NA 




NA 


NA 


955 


1003 


100 




NA 


NA 


NA 


NA 




NA 


NA 


NA 


NA 


-ll°For 


ower 






Local 99% winter design temperature: 
-11°F or lower 
















Not recommended for any vent configurations 







Note: See Figure G.19 for a map showing local 99 percent winter design temperatures in the United States. 
For SI units, 1 in. = 25.4 mm, 1 in.^ = 645 mm'^ 1 ft = 0.305 m, 1000 Btu per hr = 0.293 kW. 



2002 Edition 



54-108 



NATIONAL FUEL GAS CODE 



ANSIZ223.1-108 



Chapter 14 Referenced Publications 

14.1 General. The following documents or portions thereof 
are referenced within this code as mandatory requirements 
and shall be considered part of the requirements of this code. 
The edition indicated for each referenced mandatory docu- 
ment is the current edition as of the date of the NFPA issuance 
of this code. Annex L contains a list of other associated appli- 
ance and installation standards for informational purposes. 

14.1.1 ASME Publications. American Society of Mechanical 
Engineers, Three Park Avenue, New York, NY 10016-5990, 
(800)843-2763, www.asme.org. 

ANSI/ASME Bl.20.1, Pipe Threads, General Purpose, Inch, 1983 

(Reaffirmed 2001). 

ANSI/ASME B16.1, Cast Iron Pipe Flanges and Flanged Fittings, 

Class 25, 123, 250, and 800, 1998. 

ANSI/ASME B16.20, Metal Gaskets for Pipe Flanges, Ring Joint 

Spiral Wound and Jacketed, 2000. 

ANSI/ASME B36.10, WeUkd and Seamless Wrought-Steel Pipe, 2001. 

14.1.2 ASTM Publications. American Society for Testing and 
Materials, 100 Barr Harbor Drive, West Conshohocken, PA 
19428-2959, (610)832-9585, www.astm.org. 

ASTM A 53, Standard Specification for Pipe, Steel, Black and Hot- 
Dipped, Zinc-Coated Welded and Seamless, 2001. 
ASTM A 106, Standard Specification for Seamless Carbon Steel Pipe 
for High-Temperature Service, 1999. 

ASTM A 254, Standard Specification for Copper Brazed Steel Tubing, 
2002. 

ASTM A 539, Standard Specification for Electric Resistance-Welded 
Coiled Steel Tubing for Gas and Fuel Oil Lines, 1999. 
ASTM B 88, Specification for Seamless Copper Water Tube, 1999. 
ASTM B 210, Specification for Aluminum-Alloy Drawn Seamless 
Tubes, 2000. 

ASTM B 241, Specification for Aluminum-Alloy Seamless Pipe and 
Seamless Extruded Tube, 2000. 

ASTM B 280, Specification for Seamless Copper Tube for Air Condi- 
tioning and Refrigeration Field Service, 1999. 
ASTM D 2513, Standard Specification for Thermoplastic Gas Pressure 
Pipe, Tubing, and Fittings, 2001. 

14.1.3 CSA-America Publications. CSA-America, Inc., 8501 
East Pleasant Valley Road, Cleveland, OH 44131, (216)524- 
4990, www.csa-america.org. 

ANSI Z21.8, Installation of Domestic Gas Conversion Burners, 2000. 

ANSI Z21.24/CSA6.10, Standard for Connectors for Gas Appliances, 

1997. 

ANSI Z21.69/CSA 6.22, Connectors for Movable Gas Appliances, 

2001. 

ANSI Z21.80/CSA3.7, Line Pressure Regulators, 2001. 

ANSI Z83.4/CSA 3.7, Non-Recirculating Direct Gas Fired Industrial 

Air Heaters, 1999. 

ANSI Z83.18, Recirculating Direct Gas-Fired Industrial Air Heaters, 

1990 (2000). 

ANSI LC 1/CSA 6.26, Fu£l Gas Piping Systems Using Corrugated 

Stainless Steel Tubing, 2001. 

14.1.4 MSS Publications. Manufacturers Standardization So- 
ciety of the Valve and Fittings Industry, 124 Park Street, NE, 
Vienna, VA 22180-6671, (703)281-6613, www.mss-hq.com. 
MSS SP-6, Standard Finishes for Contact Faces of Pipe Flanges and 
Connecting-End Flanges of Valves and Fittings, 2001. 
ANSI/MSS SP-58, Pipe Hangers and Supports — Materials, Design 
and Manufacture, 1993. 



14.1.5 NFPA Publications. National Fire Protection Associa- 
tion, 1 Batterymarch Park, PO. Box 9101, Quincy, MA 02269- 
9101, (617)770-3000, www.nfpa.org. 

NFPA 30A, Code for Motor Fuel Dispensing Facilities and Repair 
Garages, 2000 edition. 

NFPA 37, Standard for the Installation and Use of Stationary Com- 
bustion Engines and Gas Turbines, 2002 edition. 
NFPA 51, Standard for the Design and Installation of Oxygen-Fuel Gas 
Systems for Welding Cutting and Allied Processes, 2002 edition. 
NFPA 52, Compressed Natural Gas (CNG) Vehicular Fuel Systems Code, 
1998 edition. 

NFPA 58, Liquefied Petroleum Gas Code, 2001 edition. 
NFPA 70, National Electrical Cod£®, 2002 edition. 
NFPA 82, Standard on Incinerators and Waste and Linen Handling 
Systems and Equipment, 1999 edition. 
NFPA88A, Standardfor Parking Structures, 2002 edition. 
NFPA90A, Standard for the Installation ofAir-Conditioningand Venti- 
lating Systems, 2002 edition. 

NFPA 90B, Standardfor the Installation of Warm Air Heating and Air- 
Conditioning Systems, 2002 edition. 

NFPA 96, Standardfor Ventilation Control and Fire Protection of Com- 
mercial Cooking Operations, 2001 edition. 

NFPA 211, Standardfor Chimneys, Fireplaces, Vents, and Solid Fuel- 
Burning Appliances, 2000 edition. 
NFPA 409, Standard on Aircraft Hangars, 2001 edition. 
NFPA 853, Standardfor the Installation of Stationary Fuel Cell Power 
Plants, 2000 edition. 
NFPA 1192, Standard on Recreational Vehicles, 2002 edition. 

14.1.6 U.S. Government Publication. U.S. Government Print- 
ing Ojffice, Washington, DC 20402, www.gpo.gov. 

Title 49, Code of Federal Regulations, Part 192. 

Annex A Explanatory Material 

Annex A is not a part of the requirements of this NFPA document 
but is included for informational purposes only. This annex contains 
explanatory material, numbered to correspond with the applicable text 
paragraphs. 

A. 1.5 The following sample ordinance is provided to assist a 
jurisdiction in the adoption of this code and is not part of this 
code. 

ORDINANCE NO. 

An ordinance of the [jurisdiction] adopting the [year] 
edition of NFPA 54/ANSI Z223.1, National Fuel Gas Code, 
documents listed in 14 of that code; prescribing regulations 
governing conditions hazardous to life and property from 
fire or explosion; providing for the issuance of permits and 

collection of fees; repealing Ordinance No. of the 

[jurisdiction] and all other ordinances and parts of ordi- 
nances in conflict therewith; providing a penalty; providing 
a severability clause; and providing for publication; and 
providing an effective date. 

BE IT ORDAINED BY THE [governing body] OF THE 
[jurisdiction]: 

SECTION 1 That the National Fuel Gas Code and docu- 
ments adopted by 14, three (3) copies of which are on file 
and are open to inspection by the public in the office of the 
[jurisdiction's keeper of records] of the [jurisdiction], are 
hereby adopted and incorporated into this ordinance as 
fully as if set out at length herein, and from the date on 
which this ordinance shall take effect, the provisions 
thereof shall be controlling within the limits of the [juris- 
diction]. The same are hereby adopted as the code of the 
[jurisdiction] for the purpose of prescribing regulations 



2002 Edition 



ANSIZ223.1-109 



ANNEX A 



54-109 



governing conditions hazardous to life and property from 
fire or explosion and providing for issuance of permits and 
collection of fees. 

SECTION 2 Any person who shall violate any provision of 
this code or standard hereby adopted or fail to comply there- 
with; or who shall violate or fail to comply with any order made 
thereunder; or who shall build in violation of any detailed 
statement of specifications or plans submitted and approved 
thereunder; or failed to operate in accordance with any certifi- 
cate or permit issued thereunder; and from which no appeal 
has been taken; or who shall fail to comply with such an order 
as affirmed or modified by or by a court of competent jurisdic- 
tion, within the time fixed herein, shall severally for each and 
every such violation and noncompliance, respectively, be 
guilty of a misdemeanor, punishable by a fine of not less than 

$ nor more than $ or by imprisonment 

for not less than 



days nor more than. 



days or by both such fine and imprisonment. The imposition 
of one penalty for any violation shall not excuse the violation 
or permit it to continue; and all such persons shall be required 
to correct or remedy such violations or defects within a reason- 
able time; and when not otherwise specified the application of 
the above penalty shall not be held to prevent the enforced 
removal of prohibited conditions. Each day that prohibited 
conditions are maintained shall constitute a separate offense. 
SECTION 3 Additions, insertions, and changes that the 
[year] edition of NFPA 54/ ANSI Z223.1, National Fuel Gas 
Code, is amended and changed in the following respects: List 
Amendments 



SECTION 4 That ordinance No. 



of [jurisdic- 



tion] entitled [fill in the tide of the ordinance or ordinances 
in effect at the present time] and all other ordinances or parts 
of ordinances in conflict herewith are hereby repealed. 

SECTION 5 That if any section, subsection, sentence, 
clause, or phrase of this ordinance is, for any reason, held to 
be invalid or unconstitutional, such decision shall not affect 
the validity or constitutionality of the remaining portions of 
this ordinance. The [governing body] hereby declares that it 
would have passed this ordinance, and each section, subsec- 
tion, clause, or phrase hereof, irrespective of the fact that any 
one or more sections, subsections, sentences, clauses, and 
phrases be declared unconstitutional. 

SECTION 6 That the [jurisdiction's keeper of records] is 
hereby ordered and directed to cause this ordinance to be 
published. [NOTE: An additional provision may be required 
to direct the number of times the ordinance is to be published 
and to specify that it is to be in a newspaper in general circu- 
lation. Posting may also be required.] 

SECTION 7 That this ordinance and the rules, regulations, 
provisions, requirements, orders, and matters established and 
adopted hereby shall take effect and be in full force and effect 
[time period] from and after the date of its final passage and 
adoption. 

A.3.3.15 Approved. The American Gas Association and the 
National Fire Protection Association do not approve, inspect, 
or certify any installations, procedures, equipment, or materi- 
als; nor do they approve or evaluate testing laboratories. In 
determining the acceptability of installations, procedures, 
equipment, or materials, the authority havingjurisdiction may 
base acceptance on compliance with NFPA or other appropri- 
ate standards. In the absence of such standards, said authority 
may require evidence of proper installation, procedure, or 
use. The authority havingjurisdiction may also refer to the 



listings or labeling practices of an organization that is con- 
cerned with product evaluations and is thus in a position to 
determine compliance with appropriate standards for the cur- 
rent production of listed items. 

A.3.3.17 Authority Having Jurisdiction (AHJ). The phrase 
"authority havingjurisdiction," or its acronym AHJ, is used in 
this code in a broad manner, since jurisdictions and approval 
agencies vary, as do their responsibilities. Where public safety 
is primary, the authority havingjurisdiction may be a federal, 
state, local, or other regional department or individual such as 
a fire chief; fire marshal; chief of a fire prevention bureau, 
labor department, or health department; building official; 
electrical inspector; or others having statutory authority. For 
insurance purposes, an insurance inspection department, rat- 
ing bureau, or other insurance company representative may 
be the authority havingjurisdiction. In many circumstances, 
the property owner or his or her designated agent assumes the 
role of the authority havingjurisdiction; at government instal- 
lations, the commanding officer or departmental official may 
be the authority havingjurisdiction. 

A.3.3.I40 Listed. The means for identifying listed equipment 
may vary for each organization concerned with product evalu- 
ation; some organizations do not recognize equipment as 
listed unless it is also labeled. The authority havingjurisdic- 
tion should utilize the system employed by the listing organi- 
zation to identify a listed product. 

A.3.3.230 Vented Appliance, Category I. For additional infor- 
mation on appliance categorization as shovm in 3.3.230 through 
3.3.233, see the appropriate Z21 and Z83 American National 
Standards. 

A.3. 3.236 Venting System, A venting system is usually com- 
posed of a vent or a chimney and vent connector(s), if used, 
assembled to form the open passageway. 

A.5.4.1 The size of gas piping depends on the following factors: 

( 1 ) Allowable loss in pressure (see 5. 4. 4) from point of delivery 
to equipment 

(2) Maximum gas demand 

(3) Length of piping and number of fittings 

(4) Specific gravity of the gas 

(5) Diversity factor 

(6) Foreseeable future demand 

A.5.4.2 To obtain the cubic feet per hour of gas required, 
divide the Btu per hour rating by the Btu per cubic foot heat- 
ing value of the gas supplied. The heating value of the gas can 
be obtained from the local gas supplier. 

Where the ratings of the equipment to be installed are not 
known. Table 5.4.2.1 shows the approximate demand of typi- 
cal appliances by types. 

A.5.4.3 Gas Piping Size. The gas-carrying capacities for differ- 
ent sizes and lengths of iron pipe, or equivalent rigid pipe, and 
semirigid tubing are shown in the capacity tables in Chapter 12. 

Table 12.1 through Table 12.21 indicate approximate capaci- 
ties for single runs of piping. If the specific gravity of the gas is 
other than 0.60, correction factors should be applied. Correction 
factors for use with these tables are given in Table C.2(d). 

For any gas piping system, for special gas utilization equip- 
ment, or for conditions other than those covered by the capacity 
tables in Chapter 12, such as longer runs, greater gas demands, 
or greater pressure drops, the size of each gas piping system 
should be determined by the pipe sizing equation in 12.3 or by 



2002 Edition 



54-110 



NATIONAL FUEL GAS CODE 



ANSIZ223.1-110 



standard engineering methods acceptable to the authority hav- 
ingjurisdiction. 

A suggested procedure with an example of using tables to 
size a gas piping system is presented in Annex C. 

A.5.5.1(l) For welding specifications and procedures that 
can be used, see the API 1104, Standard for Welding Pipelines and 
Related Facilities; AWS B2.1, Standard for Welding Procedure and 
Performance Qualification; or ASME Boiler and Pressure Vessel Code, 
Section IX. 

A.5.6.2.3 An average of 0.3 grains of hydrogen sulfide per 
100 scf (0.7 mg/100 L) is equivalent to a trace as determined by 
ANSI/ASTM D 2385, Method of Test for Hydrogen Sulfide and Mer- 
captan Sulfur in Natural Gas (Cadmium Sulfate — lodometric Titration 
Method), or ANSI/ASTM D 2420, Method of Test for Hydrogen Sulfide 
in Liquefied Petroleum (LP) Gases (Lead Acetate Method). 

A.5.6.3.2 See A.5.6.2.3. 

Copper and brass tubing and fittings (except tin-lined cop- 
per tubing) should not be used if the gas contains more than 
an average of 0.3 grains of hydrogen sulfide per 100 scf of gas 
(0.7 mg/100 L). 

A.5. 6.8.1 For welding and brazing specificadons and proce- 
dures that can be used, see API 1104, Standard for Welding Pipe- 
lines and Related Facilities; AWS B2.1, Standard for Welding Proce- 
dure and Performance Qualification; AWS B2.2, Standard for 
Brazing Procedure and Performance Qualification; or ASME Boiler 
and Pressure Vessel Code, Section IX. 

A.5.7 This section applies to premises-owned meters [see 
1.1.1.2(16)]. 

A.5.8 This section applies to premises-owned regulators [see 
1.1.1.2(16)]. 

A.6.1.3 For information on corrosion protection of under- 
ground pipe, see NACE RP 0169, Control of External Corrosion on 
Underground or Submerged Metallic Piping Systems. Information 
on installation, maintenance, and corrosion protection may 
be available from the gas supplier. 

A.6.1.4 The gas supplier can be consulted for recommen- 
dations. 

A.6.2.5 It is the intent that gas piping, shutoff valves required 
by this code, and regulators be allowed to be installed in acces- 
sible portions of plenums, accessible ducts used to supply com- 
bustion and ventilation air in accordance with Section 5.3, and 
accessible spaces between a fixed ceiling and dropped ceiling. 

A.6.4.3 Only vertical chases are recognized by the coverage. 
It is believed that welded joints for a horizontal gas line would 
be preferable to a horizontal chase. 

A.6.5.3 Care should be taken in making mitered joints to 
provide proper root opening and alignment and full weld 
penetration. 

A.6.12.4 The mixing blower is acknowledged as a special case 
because of its inability to tolerate control valves or comparable 
restrictions between mixing blower and burner (s). With these 
limitations, mixing blower installations are not required to uti- 
lize safety blowouts, backfire preventers, explosion heads, 
flame arresters, or automatic firechecks that introduce pres- 
sure losses. 

A.6.12.5.1 For information on venting of deflagrations, see 
NFPA 68, Guide for Venting of Deflagrations. 



A.6. 12.5.4 Additional interlocks might be necessary for safe 
operation of equipment supplied by the gas-mixing machine. 

A.6. 12.6(1) Two basic methods are generally used. One calls for 
a separate firecheck at each burner, the other a firecheck at each 
group of burners. The second method is generally more practical 
if a system consists of many closely spaced burners. 

An approved automatic firecheck should be installed as near 
as practical upstream from a flame arrester used for local protec- 
tion where test burners or lighting torches are employed. 

A.7.1.1 Because it is sometimes necessary to divide a piping 
system into test sections and install test heads, connecting pip- 
ing, and other necessary appurtenances for testing, it is not 
required that the tie-in sections of pipe be pressure-tested. 
Tie-in connections, however, should be tested with a noncor- 
rosive leak detection fluid after gas has been introduced and 
the pressure has been increased sufiiciently to give some indi- 
cations whether leaks exist. 

The test procedure used should be capable of disclosing all 
leaks in the section being tested and should be selected after 
giving due consideration to the volumetric content of the sec- 
tion and to its location. 

Under no circumstances should a valve in a line be used as a 
bulkhead between gas in one section of the piping system and 
test medium in an adjacent section, unless two valves are installed 
in series with a valved "telltale" located between these valves. A 
valve should not be subjected to the test pressure imless it can be 
determined that the valve, including the valve closing mecha- 
nism, is designed to safely withstand the test pressure. 

A.7.2.3 See Annex D for a suggested method. 

A.7.3 The processes of purging a gas pipeline of fuel gas and 
replacing the fuel gas with air or charging a gas pipeline that is 
full of air with fuel gas require that a significant amount of 
combustible mixture not be developed within the pipeline or 
released within a confined space. 

A.8.1.1 The American Gas Association, American National 
Standards Institute, and the National Fire Protection Associa- 
tion do not approve, inspect, or certify any installations, pro- 
cedures, equipment, or materials. In determining acceptabil- 
ity of installations or procedures, the authority having 
jurisdiction can base acceptance on compliance with AGA, 
ANSI, or NFPA, or other appropriate standards. In the ab- 
sence of such standards, said authority can require evidence of 
proper installation, procedure, or use. The authority having 
jurisdiction can also refer to the listings or labeling practices 
(see Section 3.3) of an organization concerned with product 
evaluations and is in a position to determine compliance with 
appropriate standards for the current production of listed 
items. Additional information regarding the coordination of 
gas utilization equipment design, construction, and mainte- 
nance can be found in Annex B. 

A.8.1.6 Halogenated hydrocarbons are particularly injurious 
and corrosive after contact with flames or hot surfaces. 

A.8.3 Special Conditions Created by Mechanical Exhausting or 
Fireplaces. Operation of exhaust fans, ventilation systems, 
clothes dryers, or fireplaces can create conditions requiring 
special attention to avoid unsatisfactory operation of installed 
gas utilization equipment. 

A.8.3.2.1 See Table A.8.3.2.1. 

A.8.3.2.2 See Table A.8.3.2.1 and Table A.8.3.2.2(b). 



2002 Edition 



ANSIZ223.1-111 



ANNEX A 



54-111 



Table A.8.3.2.1 Standard Method: Required Volume, All 
Appliances 



Appliance Input 


Required Volume 


(Btu/hr) 


(ft") 


5,000 


250 


10,000 


500 


15,000 


750 


20,000 


1,000 


25,000 


1,250 


30,000 


1,500 


35,000 


1,750 


40,000 


2,000 


45,000 


2,250 


50,000 


2,500 


55,000 


2,750 


60,000 


3,000 


65,000 


3,250 


70,000 


3,500 


75,000 


3,750 


80,000 


4,000 


85,000 


4,250 


90,000 


4,500 


95,000 


4,750 


100,000 


5,000 


105,000 


5,250 


110,000 


5,500 


115,000 


5,750 


120,000 


6,000 


125,000 


6,250 


130,000 


6,500 


135,000 


6,750 


140,000 


7,000 


145,000 


7,250 


150,000 


7,500 


160,000 


8,000 


170,000 


8,500 


180,000 


9,000 


190,000 


9,500 


200,000 


10,000 


210,000 


10,500 


220,000 


11,000 


230,000 


11,500 


240,000 


12,000 


250,000 


12,500 


260,000 


13,000 


270,000 


13,500 


280,000 


14,000 


290,000 


14,500 


300,000 


15,000 



Table A.8.3.2.2(a) Known Air Infiltration Rate Method, 
Minimum Space Volume for Appliances Other than Fan 
Assisted, for Specified Infiltration Rates (ACH) 



A.8.3.2.3(l) See Figure A.8.3.2.3(l). 

A.8.3.3.1(l) See Figure A8.3.3.1(l) (a) and Figure A8.3.3.1(l)(b). 

A.8.3.3.1(2) See Figure A.8.3.3.1 (2). 

A.8.3.3.2 See Figure A.8.3.3.2. 

A.8.5.6 For information on gas convenience outlets, see 
AGA 7-90, Requirements for Gas Convenience Outlets. 





Space 


Space 


Space 


Appliance 


Volume 


Vohime 


Volume 


Input 


0.25 ACH 


0.30 ACH 


0.35 ACH 


(Btu/hr) 


(ft") 


(ft") 


(ft") 


5,000 


420 


350 


300 


10,000 


840 


700 


600 


15,000 


1,260 


1,050 


900 


20,000 


1,680 


1,400 


1,200 


25,000 


2,100 


1,750 


1,500 


30,000 


2,520 


2,100 


1,800 


35,000 


2,940 


2,450 


2,100 


40,000 


3,360 


2,800 


2,400 


45,000 


3,780 


3,150 


2,700 


50,000 


4,200 


3,500 


3,000 


55,000 


4,620 


3,850 


3,300 


60,000 


5,040 


4,200 


3,600 


65,000 


5,460 


4,550 


3,900 


70,000 


5,880 


4,900 


4,200 


75,000 


6,300 


5,250 


4,500 


80,000 


6,720 


5,600 


4,800 


85,000 


7,140 


5,950 


5,100 


90,000 


7,560 


6,300 


5,400 


95,000 


7,980 


6,650 


5,700 


100,000 


8,400 


7,000 


6,000 


105,000 


8,820 


7,350 


6,300 


110,000 


9,240 


7,700 


6,600 


115,000 


9,660 


8,050 


6,900 


120,000 


10,080 


8,400 


7,200 


125,000 


10,500 


8,750 


7,500 


130,000 


10,920 


9,100 


7,800 


135,000 


11,340 


9,450 


8,100 


140,000 


11,760 


9,800 


8,400 


145,000 


12,180 


10,150 


8,700 


150,000 


12,600 


10,500 


9,000 


160,000 


13,440 


11,200 


9,600 


170,000 


14,280 


11,900 


10,200 


180,000 


15,120 


12,600 


10,800 


190,000 


15,960 


13,300 


11,400 


200,000 


16,800 


14,000 


12,000 


210,000 


17,640 


14,700 


12,600 


220,000 


18,480 


15,400 


13,200 


230,000 


19,320 


16,100 


13,800 


240,000 


20,160 


16,800 


14,400 


250,000 


21,000 


17,500 


15,000 


260,000 


21,840 


18,200 


15,600 


270,000 


22,680 


18,900 


16,200 


280,000 


23,520 


19,600 


16,800 


290,000 


24,360 


20,300 


17,400 


300,000 


25,200 


21,000 


18,000 



I Note: ACH = air change per hour. 



2002 Edition 



54-112 



NATIONAL FUEL GAS CODE 



ANSIZ223.1-112 



Table A.8.3.2.2(b) Known Air Infiltration Rate Method, 
Minimum Space Volume for Fan Assisted Appliance, for 
Specified Infiltration Rates (ACH) 





Required 


Required 


Required 


Appliance 


Volume 


Volume 


Volume 


Input 


0.25 ACH 


0.30 ACH 


0.35 ACH 


(Btii/hr) 


(ft') 


(ft') 


(ft') 


5,000 


300 


250 


214 


10,000 


600 


500 


429 


15,000 


900 


750 


643 


20,000 


1,200 


1,000 


857 


25,000 


1,500 


1,250 


1,071 


30,000 


1,800 


1,500 


1,286 


35,000 


2,100 


1,750 


1,500 


40,000 


2,400 


2,000 


1,714 


45,000 


2,700 


2,250 


1,929 


50,000 


3,000 


2,500 


2,143 


55,000 


3,300 


2,750 


2,357 


60,000 


3,600 


3,000 


2,571 


65,000 


3,900 


3,250 


2,786 


70,000 


4,200 


3,500 


3,000 


75,000 


4,500 


3,750 


3,214 


80,000 


4,800 


4,000 


3,429 


85,000 


5,100 


4,250 


3,643 


90,000 


5,400 


4,500 


3,857 


95,000 


5,700 


4,750 


4,071 


100,000 


6,000 


5,000 


4,286 


105,000 


6,300 


5,250 


4,500 


110,000 


6,600 


5,500 


4,714 


115,000 


6,900 


5,750 


4,929 


120,000 


7,200 


6,000 


5,143 


125,000 


7,500 


6,250 


5,357 


130,000 


7,800 


6,500 


5,571 


135,000 


8,100 


6,750 


5,786 


140,000 


8,400 


7,000 


6,000 


145,000 


8,700 


7,250 


6,214 


150,000 


9,000 


7,500 


6,429 


160,000 


9,600 


8,000 


6,857 


170,000 


10,200 


8,500 


7,286 


180,000 


10,800 


9,000 


7,714 


190,000 


11,400 


9,500 


8,143 


200,000 


12,000 


10,000 


8,571 


210,000 


12,600 


10,500 


9,000 


220,000 


13,200 


11,000 


9,429 


230,000 


13,800 


11,500 


9,857 


240,000 


14,400 


12,000 


10,286 


250,000 


15,000 


12,500 


10,714 


260,000 


15,600 


13,000 


11,143 


270,000 


16,200 


13,500 


11,571 


280,000 


16,800 


14,000 


12,000 


290,000 


17,400 


14,500 


12,429 


300,000 


18,000 


15,000 


12,857 



Note: ACH = air change per hour. 



Chimney or gas vent 




= -< — Opening 



Opening 



' I 'i ' i'i ' 



izj: 



1 r 



1 r 



nCURE A.8.3.2.3(l) AU Combustion Air from Adjacent In- 
door Spaces through Indoor Combustion Air Openings. 



•< Chimney or gas vent 



Ventilation louvers 
(each end of attic) 




I— Ventilation louvers for 
unheated crawl space 

FIGURE A.8.3.3.1(l)(a) AU Combustion Air from Outdoors 
— Inlet Air from Ventilated Crawl Space and Outiet Air to 
Ventilated Attic. 



2002 Edition 



ANSIZ223.1-113 



ANNEX A 



54-113 



Chimney or gas vent 



Ventilation louvers 
(each end of attic) 




Inlet air duct 
[ends 1 ft (300 mm) 
above floor] 










1 


1 1 1 1 1 1 1 1 1 1 


1 


1 1 ' 1 ' 1 ' 1 ' ' ' 1 ' 1 ' 


1 1 



nCURE A.8.3.3.1(l)(b) AU Combustion Air from Outdoors 
tiirough Ventilated Attic. 



Chimney or gas vent 




Opening 



Alternate 
opening 
location 



nCURE A.8.3.3.2 All Combustion Air from Outdoors 
through Single Combustion Air Opening. 



■< Chimney or gas vent 




n 



Inlet air duct 



I . I , I . I 



I .I.I 



' I ' l 'i ' i ' i ' i ' i ' i:^ 



ill 



nCURE A.8.3.3.1(2) All Combustion Air from Outdoors 
through Horizontal Ducts. 



A.9.1.2 Also see Prohibited Installations, 9.6.1, 9.7.1, 9.8.2, 
9.9.2, and 9.23.1. 

A.9.2.6 Reference can be made to NFPA 90A, Standard for the 
Installation of Air-Conditioning and Ventilating Systems, or 
NFPA 90B, Standard for the Installation of Warm Air Heating and 
Air-Conditioning Systems. 



A.9.3.6 For details of requirements on low-pressure heating 
boiler safety devices, refer to ASME Boiler and Pressure Vessel 
Code, Section IV, "Rules for Construction of Heating Boilers." 

A.9.3.7.3 Reference can be made to NFPA90A, Standard for 
the Installation of Air Conditioning and Ventilating Systems, or to 
NFPA 90B, Standard for the Installation of Warm Air Heating and 
Air Conditioning Systems. 

A.9.6. 1 For information on decorative appliances for installa- 
tion in vented fireplaces, see ANSI Z21.60/CGA 2.26, Decora- 
tive Gas Appliances for Installation in Solid-Fuel Burning Fireplaces. 

A.9.7.1 For information on vented gas fireplaces, see ANSI 
Z21.50/CGA2.22, Vented Gas Fireplaces. 

A.9.9.2.2 Recirculation of room air can be hazardous in the 
presence of flammable solids, liquids, gases, explosive materi- 
als (e.g., grain dust, coal dust, gun powder), and substances 
(e.g., refrigerants, aerosols) that can become toxic when ex- 
posed to flame or heat. 

A.9. 1 2.8 Where exhaust fans are used for ventilation, precau- 
tions might be necessary to avoid interference with the opera- 
tion of the equipment. 

A.9.23.1 It is recommended that space heating appliances 
installed in all bedrooms or rooms generally kept closed be of 
the direct vent type. (See Section 9.27.) 

A.9.28.8 A hole near the top of a cold water inlet tube that 
enters the top of the water heater or tank is commonly ac- 
cepted for this purpose. 

A.10.2.3 Information on the construction and installation 
of ventilating hoods can be obtained from NFPA 96, Stan- 
dard for Ventilation Control and Fire Protection of Commercial 
Cooking Operations. 

A.10.3.5 See A.10.2.3. 



2002 Edition 



54-114 



NATIONAL FUEL GAS CODE 



ANSIZ223.1-114 



Mechanical 
draft vent 
terminal 
see 10.8.1) 




Direct vent terminal clearance 
Minimum clearance, C 
Input (Btu/hr) Clearance (in.) 

10.000 or less 6 

10.001 to 50,000 9 
Over 50,000 12 
(see 10.8.3) 



For SI units: 1 ft = 0.305 m; 1 in. = 25.4 mm; 
1 Btu/hr = 0.293 W 



Forced air 
inlet 



FIGURE A. 10.8 Exit Terminals of Mechanical Draft and Direct-vent Venting Systems. 



A. 10.5. 1.3 For information on the installation of gas vents in 
existing masonry chimneys, see Section 10.6. 

A. 10.5.5.3 Reference can also be made to the chapter on 
chimney, gas vent, and fireplace systems of the ASHRAE Hand- 
book — HVAC Systems and Equipment. 

A. 10.6.3.1 Additional information on sizing venting systems 
can be found in the following: 

(1) Tables in Chapter 13 

(2) The gas equipment manufacturer's instructions 

(3) The venting equipment manufacturer's sizing instruc- 
tions 

(4) Drawings, calculations, and specifications provided by the 
venting equipment manufacturer 

(5) Drav«ngs, calculations, and specifications provided by a 
competent person 

(6) The chapter on chimney, gas vent, and fireplace systems 
of the ASHRAE Handbook — HVAC Systems and Equipment. 

Category I apphances may be either draft hood-equipped 
or fan-assisted combustion system in design. Different vent de- 
sign methods are required for draft hood-equipped and fan- 
assisted combustion system appliances. 

A.10.7.5(l) Reference can also be made to the chapter on 
chimney, gas vent, and fireplace systems of the ASHRAE Hand- 
book — HVAC Systems and Equipment. 

A.10.8 See Figure A. 10.8. 

A. 10. 10.3 Reference can also be made to the chapter on 
chimney, gas vent, and fireplace systems of the ASHRAE Hand- 
book — HVAC Systems and Equipment. 



A.10.10.9.2 SeeA.10.6.3.1. 

A.10.12.4 A device that will automatically shut off gas to the 
burner in the event of sustained backdraft is recommended if 
such backdraft might adversely affect burner operation or if 
flue gas spillage might introduce a hazard. Figure A.10.12.4 
shows examples of correct and incorrect locations for baro- 
metric draft regulators. 



Correct 




N 



Correct 



¥ 



^ 



Correct 



(a) Correct locations 



Incorrect — ■ -r 

, — >3J 



Incorrect 



m 




f 

"[""pl Incorrect 

^^ Incorrect 



Incorrect 



M 



Incorrect 



(b) Incorrect locations 

FIGURE A.10.12.4 Locations for Barometric Draft 
Regulators. 



2002 Edition 



ANSIZ223.1-115 



ANNEXE 



54-115 



A.11.1.1 Checking Burner Input. Burner input can be checked 
as follows: 

( 1 ) Checking Burner Input Using a Meter. To check the Btu input 
rate, the test hand on the meter should be timed for at 
least one revolution and the input determined from this 
timing. Test dials are generally marked V2, 1, 2, or 5 ft^/ 
revolution depending on the size of the meter. Instruc- 
tions for converting the test hand readings to cubic feet 
per hour are given in Table 11.1.1. 

(2) Checking Burner Input Not Using a Meter. The fixed orifice 
size for each burner can be determined in accordance 
with for utility gases and for undiluted liquefied petro- 
leum gases. 

A. 11. 2 Normally, the primary air adjustment should first be 
set to give a soft blue flame having luminous tips and then 
increased to a point where the yellow dps just disappear. If the 
burner cannot be so adjusted, the manufacturer or serving gas 
supplier should be contacted. 

A.11.6 Aprocedure for checking draft can be found in Annex 
H, steps 7, 8, and 10 through 14. 

A. 12. 1.1 Longest Length Method. The longest length method is 
the traditional method used to determine the equivalent pip- 
ing length L that is then used along with the pipe sizing tables 
to determine the appropriate pipe diameter size. 

A. 12. 1.2 Branch Length Method. This method is an alternate 
sizing method that could permit slighdy smaller pipe diam- 
eters in some segments of a piping system when compared 
with the longest length method. 

A. 12.3.1 Low Pressure Formula. The presented formula is the 
standard flow formula located in Annex C but rearranged to 
solve for the pipe diameter. 

A. 12.3.2 High Pressure Formula. The presented formula is the 
standard flow formula located in Annex C but rearranged to 
solve for the pipe diameter. 

A. 13. 1.7 A long radius turn is a turn where the centerline 
radius is equal to or greater than 1.5 times the vent diameter. 

A.13.2.19 A long radius turn is a turn where the centerline 
radius is equal to or greater than 1.5 times the vent diameter. 



Annex B Coordination of Gas Utilization Equipment 
Design, Construction, and Maintenance 

This annex is not a part of the requirements of this code but is 
included for informational purposes only. 

B.l Coordination. 

B.1.1 Because industrial gas applications are so varied in na- 
ture, many agencies are jointly involved with their safe and 
satisfactory use. Prior to installation, the specific assignments 
should be agreed upon by the parties concerned. A typical, but 
not mandatory, delineation of assignments is given in B.l. 2 
through B.l. 5, and a detailed checklist is given in B.2. 

B.1.2 The person or agency planning an installation of gas 
equipment does the following: 

(1) Verifies the adequacy of the gas supply, volume, pressure, 
and meter location 

(2) Determines suitability of gas for the process 



(3) Notifies gas suppliers of significant changes in 
requirements 

B.l. 3 Upon request, the gas supplier furnishes the user com- 
plete information on the following: 

(1) Combustion characteristics and physical or chemical 
properties such as specific gravity, heating value, pressure, 
and the approximate analysis of the gas 

(2) Conditions under which an adequate supply of gas at suit- 
able pressure can be brought to the site 

(3) Continuity of the gas supply 

B.l. 4 The gas equipment manufacturer or builder provides 
the following: 

(1) Design and construction of all gas equipment or assem- 
blies shipped from its plant 

(2) Design and construction of all gas equipment fabricated, 
erected, or assembled by the gas equipment manufac- 
turer or builder in the field 

(3) A statement of the maximum hourly Btu input, type of 
gas, and design pressure range 

(4) Written installation and operating instructions for the 
user 

B.l. 5 The person or agency installing the gas equipment and 
the person or agency authorizing the installation of gas equip- 
ment (purchaser) jointiy should do the following: 

(1) Select, erect, or assemble gas equipment, components, or 
designs purchased or developed by that person or agency 

(2) Ensure conformance to codes, ordinances, or regulations 
applicable to the installation 

(3) Provide adequate means of disposal of products of com- 
bustion 

(4) Initially operate the gas equipment in a safe manner 

B.2 Gas Equipment Design and Construction Checklist. 

B.2.1 The basic design and installation should consider the 
following: 

(1) Suitability of equipment for process requirements 

(2) Adequate structural strength and stability 

(3) Reasonable life expectancy 

(4) Conformance to existing safety standards 

(5) Adequate combustion space and venting 

(6) Means for observation and inspection of combustion 

B.2.2 Materials of construction used, other than pipe, fit- 
tings, and valves, should provide reasonable life expectancy 
for the service intended and should be capable of satisfactorily 
withstanding the following: 

(1) Operating temperatures 

(2) Chemical action 

(3) Thermal shock 

(4) Load stresses 

B.2.3 Combustion systems should be selected for the charac- 
teristics of the available gas so that they will operate properly at 
the elevation at point of use and produce the following: 

(1) Proper heat distribution 

(2) Adequate operating temperature range 

(3) Suitable flame geometry 

(4) Flame stability 

(5) Operating flexibility 

(6) Desired heating chamber atmosphere 



2002 Edition 



54-116 



NATIONAL FUEL GAS CODE 



ANSIZ223.1-116 



B.2.4 Pipe, fittings, and valves should conform to applicable 
American National Standards as indicated in Section 5.6. Pip- 
ing, bushings, and material in fittings should not be selected 
nor used until the following factors have been considered: 

(1) Correct size to handle required volume (consideration of 
pressure drop in controls and manifolds is particularly 
important in low pressure systems) 

(2) Material specifications suitable for pressures and tem- 
peratures encountered 

(3) Adequate supports and protection against physical dam- 
age 

(4) Tight assembly and thorough leak inspection 

(5) Use of sufficient unions and flanges, where permitted, for 
convenient field replacement or repair 

(6) Arrangement of piping to provide accessibility for equip- 
ment adjustments and freedom from thermal damage 

B.2.5 Information concerning the characteristics of the gas 
and electricity available at the point of utilization should be 
specific and complete. Gas controls and electrical equipment 
should be selected to conform to these characteristics, which 
include the following: 

(1) Gas characteristics: Heat content, pressure, specific grav- 
ity, and approximate analysis 

(2) Electrical characteristics: Voltages, number of phases, and 
frequencies for both control and power circuits 

(3) Location of electrical equipment and wiring to avoid ther- 
mal damage and excessive concentrations of dust, dirt, or 
foreign material 

(4) Requirements of applicable electrical codes and stan- 
dards, with particular reference to NFPA 70, Article 500, 
of the National Electrical Code. 

B.2.6 Temperature controls, if used, should be carefully se- 
lected considering: 

(1) Range and type of instruments and sensing elements 

(2) Type of control action 

(3) Suitability for service required 

(4) Correlation of control instruments with operating 
equipment 

B.2.7 In enclosed chambers, the accumulation of gas-air or 
solvent-air mixtures that can be accidentally ignited consti- 
tutes a potential hazard to life and property. For this reason, 
consideration should be given to the selection and installation 
of suitable protective equipment. The selection of a satisfac- 
tory protective system and components not otherwise covered 
by existing codes or standards should be based on the require- 
ments of each individual installation after consultation with 
the various interested parties, including the user, designer, 
insurance company, and local authorities havingjurisdiction. 
Factors and considerations involved in the selection of protec- 
tive equipment include the following: 

( 1 ) Feasibility of its installation 

(2) Its adaptability to process and control requirements 

(3) Conformance to existing standards, ordinances, require- 
ments, and other regulations that apply (See Annex Lfor 
listing of standards and specifications.) 

B.3 Maintenance of Gas Equipment. 

B.3.1 These recommendations are prepared for mainte- 
nance of gas equipment. Special types of equipment demand 
special attention. 



B.3. 2 Burners and pilots should be kept clean and in proper 
operating condition. Burner refractory parts should be exam- 
ined at frequent regular intervals to ensure good condition. 

B.3. 3 Where automatic flame safeguards are used, a com- 
plete shutdown and restart should be made at frequent inter- 
vals to check the components for proper operation. 

B.3.4 Other Safeguard Equipment. 

B. 3.4.1 Accessory safeguard equipment, such as manual reset 
valves with pressure or vacuum switches, high-temperature 
limit switches, draft controls, shutoff valves, airflow switches, 
door switches, and gas valves, should be operated at frequent 
regular intervals to ensure proper functioning. If inoperative, 
they should be repaired or replaced promptiy. 

B.3.4. 2 Where firechecks are installed in gas-air mixture pip- 
ing to prevent flashbacks from traveling farther upstream, the 
pressure loss across the firechecks should be measured at 
regular intervals. When excessive pressure loss is found, 
screens should be removed and cleaned. Water-type backfire 
checks should be inspected at frequent regular intervals and 
liquid level maintained. 

B.3.4.3 All safety shutoff valves should be checked for leakage 
and proper operation at frequent regular intervals. 

B.3. 5 Auxiliary Devices. 

B.3. 5.1 A necessary part of the gas equipment maintenance is 
the proper maintenance of auxiliary devices. Maintenance in- 
structions as supplied by the manufacturers of these devices 
should be followed. 

B.3.5.2 Gas combustion equipment, including blowers, me- 
chanical mixers, control valves, temperature control instru- 
ments, air valves, and air filters, should be kept clean and 
should be examined at frequent regular intervals. 

B.3. 5.3 Necessary repairs and replacements should be made 
promptly. 

B.3. 6 Regulator and zero governor vents and impulse or con- 
trol piping and tubing should be kept clear. Regulator valves 
that operate improperly should be cleaned, repaired, or re- 
placed promptiy. 

B.3.7 A necessary part of the gas equipment maintenance is the 
proper maintenance of the gas piping system. It is recommended 
that gas piping be inspected and tested for leakage at regular 
intervals in accordance with the provisions of 7.1.5. Air piping 
should be kept internally clean to prevent accumulation of dust, 
lint, and grease in air jets and valves. Where conditions warrant, 
filters should be installed at the intake to the fans. 

B.3.8 Standby or substitute fuel equipment and systems for 
gas equipment should be kept in good operating condition 
and tested periodically. 

B.3. 9 An adequate supply of repair parts should be maintained. 



Annex C Sizing and Capacities of Gas Piping 

This annex is not a part of the requirements of this code but is 
included for informational purposes only. 

C.l General. To determine the size of piping used in a gas 
piping system, the following factors must be considered: 



2002 Edition 



ANSIZ223.1-117 



ANNEX C 



54-117 



(1) Allowable loss in pressure from point of delivery to equip- 
ment 

(2) Maximum gas demand 

(3) Length of piping and number of fittings 

(4) Specific gravity of the gas 

(5) Diversity factor 

For any gas piping system, or special gas utilization equip- 
ment, or for conditions other than those covered by the tables 
provided in this code, such as longer runs, greater gas de- 
mands, or greater pressure drops, the size of each gas piping 
system should be determined by standard engineering prac- 
tices acceptable to the authority havingjurisdiction. 

C.2 Description of Tables. 

C.2.1 General. The quantity of gas to be provided at each 
oudet should be determined, whenever possible, directly from 
the manufacturer's Btu input rating of the equipment that will 
be installed. In case the ratings of the equipment to be in- 
stalled are not known, Table 5.4.2.1 shows the approximate 
consumption (in Btu per hour) of certain types of typical 
household appliances. 

To obtain the cubic feet per hour of gas required, divide 
the total Btu input of all equipment by the average Btu heating 
value per cubic foot of the gas. The average Btu per cubic foot 
of the gas in the area of the installation can be obtained from 
the serving gas supplier. 

C.2.2 Low Pressure Natural Gas Tables. Capacities for gas at 
low pressure [0.5 psig (3.5 kPa gauge) or less] in cubic feet per 
hour of 0.60 specific gravity gas for different sizes and lengths 
are shown in Table 12.1 and Table 12.2 for iron pipe or equiva- 
lent rigid pipe, in Table 12.7 through Table 12.9 for smooth 
wall semi-rigid tubing, in Table 12.14 through Table 12.16 for 
corrugated stainless steel tubing. Table 12.1 and Table 12.7 are 
based upon a pressure drop of 0.3 in. w.c. (75 Pa), whereas 
Table 12.2, Table 12.8, and Table 12.14 are based upon a pres- 
sure drop of 0.5 in. w.c. (125 Pa). Table 12.9, Table 12.15, and 
Table 12.16 are special low-pressure applications based upon 
pressure drops greater than 0.5 in. w.c. (125 Pa). In using 
these tables, an allowance (in equivalent length of pipe) 
should be considered for any piping run with four or more 
fittings (see Table C.2.2). 

C.2.3 Undiluted LiqueHed Petroleum Gas Tables. Capacities 
in thousands of Btu per hour of undiluted liquefied petro- 
leum gases based on a pressure drop of 0.5 in. w.c. (125 Pa) for 
different sizes and lengths are shown in Table 12.24 for iron 
pipe or equivalent rigid pipe, in Table 12.26 for smooth wall 
semi-rigid tubing, in Table 12.28 for corrugated stainless steel 
tubing, and in Table 12.31 and Table 12.33 for polyethylene 
plastic pipe and tubing. Table 12.29 and Table 12.30 for corru- 
gated stainless steel tubing and Table 12.32 polyethylene plas- 
tic pipe are based on operating pressures greater than 0.5 psi 
(3.5 kPa) and pressure drops greater than 0.5 in. w.c. (125 Pa). 
In using these tables, an allowance (in equivalent length of 
pipe) should be considered for any piping run with four or 
more fittings (see Table C.2.2). 

C.2.4 Natural Gas Specific Gravity. Gas piping systems that 
are to be supplied with gas of a specific gravity of 0.70 or less 
can be sized directly from the tables provided in this code, 
unless the authority havingjurisdiction specifies that a gravity 
factor be applied. Where the specific gravity of the gas is 
greater than 0.70, the gravity factor should be applied. 

Application of the gravity factor converts the figures given 
in the tables provided in this code to capacities for another gas 



of different specific gravity. Such application is accomplished 
by multiplying the capacities given in the tables by the multi- 
pliers shown in Table C.2.4. In case the exact specific gravity 
does not appear in the table, choose the next higher value 
specific gravity shown. 

C.2.5 Higher Pressure Natural Gas Tables. Capacities for gas 
at pressures greater than 0.5 psig (3.5 kPa gauge) in cubic feet 
per hour of 0.60 specific gravity gas for diflFerent sizes and 
lengths are shown in Table 12.3 through Table 12.6 for iron 
pipe or equivalent rigid pipe. Table 12.10 through Table 12.13 
for semi-rigid tubing. Table 12.17 and Table 12.18 for corru- 
gated stainless steel tubing, and Table 12.19 through Table 
12.21 for polyethylene plastic pipe. 

C.3 Use of Capacity Tables. 

C.3.1 The Longest Length Method. This sizing method is con- 
servative in its approach by applying the maximum operating 
conditions in the system as the norm for the system and by 
setting the length of pipe used to size any given part of the 
piping system to the maximum value. 

To determine the size of each section of gas piping in a 
system within the range of the capacity tables, proceed as fol- 
lows. (Also see sample calculations included in this annex.) 

(1) Divide the piping system into appropriate segments con- 
sistent with the presence of tees, branch lines, and main 
runs. For each segment, determine the gas load (assum- 
ing all appliances operate simultaneously) and its overall 
length. An allowance (in equivalent length of pipe) as 
determined from Table C.2.2, shall be considered for pip- 
ing segments that include four or more fittings. 

(2) Determine the gas demand of each appliance to be at- 
tached to the piping system. Where Table 12.1 through 
Table 12.23 are to be used to select the piping size, calcu- 
late the gas demand in terms of cubic feet per hour for 
each piping system outiet. Where Table 12.24 through 
Table 12.33 are to be used to select the piping size, calcu- 
late the gas demand in terms of thousands of Btu per 
hour for each piping system outiet. 

(3) Where the piping system is for use with other than undi- 
luted liquefied petroleum gases, determine the design sys- 
tem pressure, the allowable loss in pressure (pressure 
drop), and specific gravity of the gas to be used in the 
piping system. 

(4) Determine the length of piping from the point of delivery 
to the most remote outiet in the building/piping system. 

(5) In the appropriate capacity table, select the row showing 
the measured length or the next longer length if the table 
does not give the exact length. This is the only length used 
in determining the size of any section of gas piping. If the 
gravity factor is to be applied, the values in the selected 
row of the table are multiplied by the appropriate multi- 
plier from Table C.2.4. 

(6) Use this horizontal row to locate ALL gas demand figures 
for this particular system of piping. 

(7) Starting at the most remote outiet, find the gas demand 
for that oudet in the horizontal row just selected. If the 
exact figure of demand is not shown, choose the next 
larger figure left in the row. 

(8) Opposite this demand figure, in the first row at the top, 
the correct size of gas piping will be found. 

(9) Proceed in a similar manner for each oudet and each 
section of gas piping. For each section of piping, deter- 
mine the total gas demand supplied by that section. 



2002 Edition 



54-118 



NATIONAL FUEL GAS CODE 



ANSIZ223.1-118 



When a large number of piping components (such as el- 
bows, tees, and valves) are installed in a pipe run, additional 
pressure loss can be accounted for by the use of equivalent 
lengths. Pressure loss across any piping component can be 
equated to the pressure drop through a length of pipe. The 
equivalent length of a combination of only four elbows/tees 
can result in a jump to the next larger length row, resulting in 
a significant reduction in capacity. The equivalent lengths in 
feet shown in Table C.2.2 have been computed on a basis that 
the inside diameter corresponds to that of Schedule 40 
(standard-weight) steel pipe, which is close enough for most 
purposes involving other schedules of pipe. Where a more 
specific solution for equivalent length is desired, this may be 
made by multiplying the actual inside diameter of the pipe in 
inches by n/l2, or the actual inside diameter in feet by n. N 
can be read from the table heading. The equivalent length 
values can be used with reasonable accuracy for copper or 



brass fittings and bends although the resistance per foot of 
copper or brass pipe is less than that of steel. For copper or 
brass valves, however, the equivalent length of pipe should be 
taken as 45 percent longer than the values in the table, which 
are for steel pipe. 

C.3.2 The Branch Length Method. This sizing method re- 
duces the amount of conservatism built into the traditional 
Longest Length Method. The longest length as measured 
from the meter to the farthest remote appliance is only used to 
size the initial parts of the overall piping system. The Branch 
Length Method is applied in the following manner: 

(1) Determine the gas load for each of the connected appli- 
ances. 

(2) Starting from the meter, divide the piping system into a 
number of connected segments, and determine the 
length and amount of gas that each segment would carry 



Table C.2.2 Equivalent Lengths of Pipe Fittings and Valves 


















Screwed Fittings^ 


90° Welding Elbows and Smooth Bends^ 




45VEU 


90VEU 


180° 
Close 
Return 
Bends 


Tee 


R/d=l 


R/d = 

11/3 


R/d=2 


R/d=4 


R/d=6 


R/d=8 


k factor = 


0.42 


0.90 


2.00 


1.80 


0.48 


0.36 


0.27 


0.21 


0.27 


0.36 


L/d^ ratio* n = 


14 


30 


67 


60 


16 


12 


9 


7 


9 


12 


Nominal 
Pipe 
Size 

(in.) 


Inside 

Diam. rf(in.), 

Sched. 40® 


^ 


# 


^ 


^ 


C^ 


R^ 











L = Equivalent Length in Feet of Schedule 40 (Standard Weight) Straight Pipe* 



1/2 


0.622 


0.73 


1.55 


3.47 


3.10 


0.83 


0.62 


0.47 


0.36 


0.47 


0.62 


% 


0.824 


0.96 


2.06 


4.60 


4.12 


1.10 


0.82 


0.62 


0.48 


0.62 


0.82 


1 


1.049 


1.22 


2.62 


5.82 


5.24 


1.40 


1.05 


0.79 


0.61 


0.79 


1.05 


11/4 


1.380 


1.61 


3.45 


7.66 


6.90 


1.84 


1.38 


1.03 


0.81 


1.03 


1.38 


11/2 


1.610 


1.88 


4.02 


8.95 


8.04 


2.14 


1.61 


1.21 


0.94 


1.21 


1.61 


2 


2.067 


2.41 


5.17 


11.5 


10.3 


2.76 


2.07 


1.55 


1.21 


1.55 


2.07 


21/2 


2.469 


2.88 


6.16 


13.7 


12.3 


3.29 


2.47 


1.85 


1.44 


1.85 


2.47 


3 


3.068 


3.58 


7.67 


17.1 


15.3 


4.09 


3.07 


2.30 


1.79 


2.30 


3.07 


4 


4.026 


4.70 


10.1 


22.4 


20.2 


5.37 


4.03 


3.02 


2.35 


3.02 


4.03 


5 


5.047 


5.88 


12.6 


28.0 


25.2 


6.72 


5.05 


3.78 


2.94 


3.78 


5.05 


6 


6.065 


7.07 


15.2 


33.8 


30.4 


8.09 


6.07 


4.55 


3.54 


4.55 


6.07 


8 


7.981 


9.31 


20.0 


44.6 


40.0 


10.6 


7.98 


5.98 


4.65 


5.98 


7.98 


10 


10.02 


11.7 


25.0 


55.7 


50.0 


13.3 


10.0 


7.51 


5.85 


7.51 


10.0 


12 


11.94 


13.9 


29.8 


66.3 


59.6 


15.9 


11.9 


8.95 


6.96 


8.95 


11.9 


14 


13.13 


15.3 


32.8 


73.0 


65.6 


17.5 


13.1 


9.85 


7.65 


9.85 


13.1 


16 


15.00 


17.5 


37.5 


83.5 


75.0 


20.0 


15.0 


11.2 


8.75 


11.2 


15.0 


18 


16.88 


19.7 


42.1 


93.8 


84.2 


22.5 


16.9 


12.7 


9.85 


12.7 


16.9 


20 


18.81 


22.0 


47.0 


105 


94.0 


25.1 


18.8 


14.1 


11.0 


14.1 


18.8 


24 


22.63 


26.4 


56.6 


126 


113 


30.2 


22.6 


17.0 


13.2 


17.0 


22.6 



2002 Edition 



1 



ANSIZ223.1-119 



ANNEX C 



54-119 



assuming that all appliances were operated simulta- 
neously. An allowance (in equivalent length of pipe) as 
determined from Table C.2.2 should be considered for 
piping segments that include four or more fittings. 

(3) Determine the distance from the outlet of the gas meter 
to the appliance farthest removed from the meter. 

(4) Using the longest distance (found in Step 3), size each 
piping segment from the meter to the most remote appli- 
ance outlet. 

(5) For each of these piping segments, use the longest length 
and the calculated gas load for all of the connected appli- 
ances for the segment and begin the sizing process in 
Steps 6 through 8. 

(6) Referring to the appropriate sizing table (based on operat- 
ing conditions and piping material), find the longest length 
distance in the first column or the next larger distance if the 
exact distance is not listed. The use of alternative operating 



pressures and/or pressure drops will require the use of a 
different sizing table, but will not alter the sizing methodol- 
ogy. In many cases, the use of alternative operating pressures 
and/or pressure drops will require the approval of both the 
authority havingjurisdiction and the local gas serving utility. 

(7) Trace across this row until the gas load is found or the 
closest larger capacity if the exact capacity is not listed. 

(8) Read up the table column and select the appropriate pipe 
size in the top row. Repeat Steps 6, 7, and 8 for each pipe 
segment in the longest run. 

(9) Size each remaining section of branch piping not previ- 
ously sized by measuring the distance from the gas meter 
location to the most remote oudet in that branch, using 
the gas load of attached appliances and follow the proce- 
dures of Steps 2 through 8. 



Table C.2.2 Continued 



Miter Elbows^ (No. of Miters) 



Welding Tees 



Valves (Screwed, Flanged, or Welded) 



1-45° 



1-60° 



1-90° 



2-90° 



3-90° 



Forged 



Miter"* 



Gate 



Globe 



Angle 



Swing 
Check 



0.45 



0.90 



1.80 



0.60 



0.45 



1.35 



1.80 



0.21 



10 



5.0 



2.5 



15 



30 



60 



20 



15 



45 



60 



333 



167 



83 



u> 



R> 



■il 



5 



5 



Q 



a 







L = Equivalent Length in Feet of Schedule 40 (Standard Weight) Straight Pipe® 






0.78 


1.55 


3.10 


1.04 


0.78 


2.33 


3.10 


0.36 


17.3 


8.65 


4.32 


1.03 


2.06 


4.12 


1.37 


1.03 


3.09 


4.12 


0.48 


22.9 


11.4 


5.72 


1.31 


2.62 


5.24 


1.75 


1.31 


3.93 


5.24 


0.61 


29.1 


14.6 


7.27 


1.72 


3.45 


6.90 


2.30 


1.72 


5.17 


6.90 


0.81 


38.3 


19.1 


9.58 


2.01 


4.02 


8.04 


2.68 


2.01 


6.04 


8.04 


0.94 


44.7 


22.4 


11.2 


2.58 


5.17 


10.3 


3.45 


2.58 


7.75 


10.3 


1.21 


57.4 


28.7 


14.4 


3.08 


6.16 


12.3 


4.11 


3.08 


9.25 


12.3 


1.44 


68.5 


34.3 


17.1 


3.84 


7.67 


15.3 


5.11 


3.84 


11.5 


15.3 


1.79 


85.2 


42.6 


21.3 


5.04 


10.1 


20.2 


6.71 


5.04 


15.1 


20.2 


2.35 


112 


56.0 


28.0 


6.30 


12.6 


25.2 


8.40 


6.30 


18.9 


25.2 


2.94 


140 


70.0 


35.0 


7.58 


15.2 


30.4 


10.1 


7.58 


22.8 


30.4 


3.54 


168 


84.1 


42.1 


9.97 


20.0 


40.0 


13.3 


9.97 


29.9 


40.0 


4.65 


222 


111 


55.5 


12.5 


25.0 


50.0 


16.7 


12.5 


37.6 


50.0 


5.85 


278 


139 


69.5 


14.9 


29.8 


59.6 


19.9 


14.9 


44.8 


59.6 


6.96 


332 


166 


83.0 


16.4 


32.8 


65.6 


21.9 


16.4 


49.2 


65.6 


7.65 


364 


182 


91.0 


18.8 


37.5 


75.0 


25.0 


18.8 


56.2 


75.0 


8.75 


417 


208 


104 


21.1 


42.1 


84.2 


28.1 


21.1 


63.2 


84.2 


9.85 


469 


234 


117 


23.5 


47.0 


94.0 


31.4 


23.5 


70.6 


94.0 


11.0 


522 


261 


131 


28.3 


56.6 


113 


37.8 


28.3 


85.0 


113 


13.2 


629 


314 


157 



For SI units, 1 ft = 0.305 m. 

Note: Values for welded fittings are for conditions where bore is not obstructed by weld spatter or backing rings. If appreciably obstructed, use 

values for "Screwed Fittings." 

^Flanged fittings have three-fourths the resistance of screwed elbows and tees. 

^Tabular figures give the extra resistance due to curvature alone to which should be added the full length of travel. 

^Small size socket-welding fitdngs are equivalent to miter elbows and miter tees. 

^Equivalent resistance in number of diameters of straight pipe computed for a value of/- 0.0075 from the relation n - k/4f. 

^For condition of minimum resistance where the centerline length of each miter is between dand 2V2d. 

^For pipe having other inside diameters, the equivalent resistance may be computed from the above n values. 

Source: From Piping Handbook, Table XIV, pp. 100-101. Used by permission of McGraw-Hill Book Company. 



2002 Edition 



54-120 



NATIONAL FUEL GAS CODE 



ANSIZ223.1-120 



Table C.2.4 SPECIAL USE: MultipUers to Be Used with 
Tables 12.1 Through 12.21 When the Specific Gravity of the 
Gas Is Other than 0.60 



Specific 




Specific 




Gravity 


MultipUer 


Gravity 


Multiplier 


0.35 


1.31 


1.00 


0.78 


0.40 


1.23 


1.10 


0.74 


0.45 


1.16 


1.20 


0.71 


0.50 


1.10 


1.30 


0.68 


0.55 


1.04 


1.40 


0.66 


0.60 


1.00 


1.50 


0.63 


0.65 


0.96 


1.60 


0.61 


0.70 


0.93 


1.70 


0.59 


0.75 


0.90 


1.80 


0.58 


0.80 


0.87 


1.90 


0.56 


0.85 


0.84 


2.00 


0.55 


0.90 


0.82 


2.10 


0.54 



C.3.3 Hybrid Pressure Method. The sizing of a 2 psi (13.8 kPa) gas 
piping system is performed using the traditional Longest Length 
Method but with modifications. The 2 psi (13.8 kPa) system con- 
sists of two independent pressure zones, and each zone is sized 
separately. The Hybrid Pressure Method is applied as follows. 

The 2 psi (13.8 kPa) section (from the meter to the Une 
regulator) is sized as follows: 

(1) Calculate the gas load (by adding up the name plate rat- 
ings) from all connected appliances. (In certain circum- 
stances the installed gas load may be increased up to 
50 percent to accommodate future addition of appli- 
ances.) Ensure that the line regulator capacity is adequate 
for the calculated gas load and that the required pressure 
drop (across the regulator) for that capacity does not ex- 
ceed 3/4 psi (5.2 kPa) for a 2 psi (13.8 kPa) system. If the 
pressure drop across the regulator is too high (for the 
connected gas load), select a larger regulator. 

(2) Measure the distance from the meter to the line regulator 
located inside the building. 

(3) If there are multiple line regulators, then measure the 
distance from the meter to the regulator farthest removed 
from the meter. 

(4) The maximum allowable pressure drop for the 2 psi 
(13.8 kPa) section is 1 psi (6.9 kPa). 

(5) Referring to the appropriate sizing table (based on piping 
material) for 2 psi (13.8 kPa) systems with a 1 psi (6.9 kPa) 
pressure drop, find this distance in the first column, or the 
closest larger distance if the exact distance is not listed. 

(6) Trace across this row until the gas load is found or the 
closest larger capacity if the exact capacity is not listed. 

(7) Read up the table column to the top row and select the 
appropriate pipe size. 

(8) If diere are multiple regulators in this portion of the piping 
system, each line segment must be sized for its actual gas 
load, but using the longest length previously determined 
above. 

The low pressure section (all piping downstream of the line 
regulator) is sized as follows: 

(1) Determine the gas load for each of the connected appli- 
ances. 

(2) Starting from the line regulator, divide the piping system 
into a number of connected segments and/or indepen- 
dent parallel piping segments and determine the amount 



of gas that each segment would carry assuming that all 
appliances were operated simultaneously. An allowance 
(in equivalent length of pipe) as determined from Table 
C.2.2 should be considered for piping segments that in- 
clude four or more fittings. 
(3) For each piping segment, use the actual length or longest 
length (if there are sub-branch lines) and the calculated gas 
load for that segment and begin the sizing process as follows: 

(a) Referring to the appropriate sizing table (based on 
operating pressure and piping material), find the 
longest length distance in the first column or the clos- 
est larger distance if the exact distance is not listed. 
The use of alternative operating pressures and/or 
pressure drops will require the use of a different siz- 
ing table, but will not alter the sizing methodology. In 
many cases, the use of alternative operating pressures 
and/or pressure drops may require the approval of 
the authority havingjurisdiction. 

(b) Trace across this row until the appliance gas load is 
found or the closest larger capacity if the exact capac- 
ity is not listed. 

(c) Read up the table column to the top row and select 
the appropriate pipe size. 

(d) Repeat this process for each segment of the piping 
system. 

C.4 Use of Sizing Equations. Capacities of smooth wall pipe or 
tubing can also be determined by using the following formulae: 

(1) High Pressure [1.5 psi (10.3 kPa) and above]: 



Q = 181.6 



= 2237i)' 



Or ■ fla ■ L 



CrL 



(2) Low Pressure [less than 1.5 psi (10.3 kPa)]: 



Q = 187.3 



D-AH 

Cr ■ fia ■ L 



= 231 3D' 



AH 
CrL 



where: 
Q = rate, cubic feet per hour at 60°F and 30 in. 

mercury column 
D = inside diameter of pipe, in. 
Pj = upstream pressure, psia 
Pg - downstream pressure, psia 
Y = superexpansibility factor = 
1/supercompressibility factor 
fla = Base friction factor for air at 60°F (CF = 1) 
L = Length of pipe, ft 
H = Pressure drop, in. w.c. (27.7 in. HgO = 1 psi) = 

0.00354 ST(Z/Sf-^^^ 
Cr - Factor for viscosity, density, and temperature 
S - Specific gravity of gas at 60°F and 30 in. mercury 

column (0.60 for natural gas, 1.53 for propane) 
T = Absolute temperature, °F or = t + 460 
t - Temperature, °F 

Z = Viscosity of gas, centipoise (0.012 for natural gas, 
0.008 for propane), or = 1488 



2002 Edition 



ANSIZ223.1-121 



ANNEX C 



54-121 



See Table 12.3.2 for values of Grand Yfor natural gas and 
propane. 

C.5 Pipe and Tube Diameters. Where the internal diameter is 
determined by the formulas in Section 12.3, Table C.5 (a) and 
Table C.5(b) can be used to select the nominal or standard 
pipe size based on the calculated internal diameter. 

Table C.5(a) Schedule 40 Steel Pipe Standard Sizes 





Internal 




Internal 


Nominal Size 


Diameter 


Nominal Size 


Diameter 


(in.) 


(in.) 


(in.) 


(in.) 


1/4 


0.364 


11/2 


1.610 


% 


0.493 


2 


2.067 


1/2 


0.622 


21/2 


2.469 


3/4 


0.824 


3 


3.068 


1 


1.049 


31/2 


3.548 


11/4 


1.380 


4 


4.026 



Table C.5(b) Copper 


Tube Standard Sizes 






Nominal 






Nominal 






or 


Internal 




or 


Internal 


Tube 


Standard Diameter 


Tube 


Standard 


Diameter 


Type 


Size (in.) 


(in.) 


Type 


Size (in.) 


(in.) 


K 


1/4 


0.305 


K 


1 


0.995 


L 


1/4 


0.315 


L 


1 


1.025 


ACR (D) 


3/8 


0.315 


ACR 

(DA) 


11/8 


1.025 


ACR (A) 


3/8 


0.311 


K 


11/4 


1.245 


K 


3/8 


0.402 


L 


11/4 


1.265 


L 


3/8 


0.430 


ACR 

(DA) 


13/8 


1.265 


ACR (D) 


1/2 


0.430 


K 


11/2 


1.481 


ACR (A) 


1/2 


0.436 


L 


11/2 


1.505 


K 


1/2 


0.527 


ACR 

(DA) 


1% 


1.505 


L 


1/2 


0.545 


K 


2 


1.959 


ACR (D) 


% 


0.545 


L 


2 


1.985 


ACR (A) 


% 


0.555 


ACR 

(DA) 


21/8 


1.985 


K 


5/8 


0.652 


K 


21/2 


2.435 


L 


% 


0.666 


L 


21/2 


2.465 


ACR (D) 


3/4 


0.666 


ACR 

(DA) 


2% 


2.465 


ACR (A) 


3/4 


0.680 


K 


3 


2.907 


K 


3/4 


0.745 


L 


3 


2.945 


L 


% 


0.785 


ACR 

(DA) 


31/8 


2.945 


ACR 


% 


0.785 








(DA) 













C.6 Use of Sizing Charts. A third method of sizing gas piping 
is detailed below as an option that is useful when large quanti- 
ties of piping are involved in a job (e.g., an apartment house) 
and material costs are of concern. If the user is not completely 
familiar with this method, the resulting pipe sizing should be 
checked by a knowledgeable gas engineer. The sizing charts 
are applied as follows: 



(1) With the layout developed according to Section 2.1 of the 
code, indicate in each section the design gas flow under 
maximum operation conditions. For many layouts, the 
maximum design flow v^U be the sum of all connected 
loads. However, in some cases, certain combinations of 
utilization equipment will not occur simultaneously (e.g., 
gas heating and air conditioning). For these cases, the 
design flow is the greatest gas flow that can occur at any 
one time. 

(2) Determine the inlet gas pressure for the system being de- 
signed. In most cases, the point of inlet will be the gas 
meter or service regulator, but in the case of a system 
addition, it could be the point of connection to the exist- 
ing system. 

(3) Determine the minimum pressure required at the inlet to 
the critical utilization equipment. Usually, the critical 
item will be the piece of equipment with the highest re- 
quired pressure for satisfactory operation. If several items 
have the same required pressure, it will be the one with 
the greatest length of piping from the system inlet. 

(4) The difference between the inlet pressure and critical 
item pressure is the allowable system pressure drop. Figure 
C.6 (a) and Figure C.6(b) show the relationship between 
gas flow, pipe size, and pipe length for natural gas with 
0.60 specific gravity. 

(5) To use Figure C.6(a) (low pressure applications), calcu- 
late the piping length from the inlet to the critical utiliza- 
tion equipment. Increase this length by 50 percent to al- 
low for fittings. Divide the allowable pressure drop by the 
equivalent length (in hundreds of feet) to determine the 
allowable pressure drop per hundred feet. Select the pipe 
size from Figure C.6(a) for the required volume of flow. 

(6) To use Figure C.6(b)(high pressure applications), calcu- 
late the equivalent length as above. Calculate the index 
number for Figure C.6(b) by dividing the diflierence be- 
tween the squares of the absolute values of inlet and out- 
let pressures by the equivalent length (in hundreds of 
feet). Select the pipe size from Figure C.6(b) for the gas 
volume required. 

C.7 Examples of Piping System Design and Sizing. 

C.7.1 Example 1 — Longest Length Method. Determine the 
required pipe size of each section and oudet of the piping 
system shown in Figure C.7.1, with a designated pressure drop 
of 0.50 in. w.c. (125 Pa) using the Longest Length Method. 
The gas to be used has 0.60 specific gravity and a heating value 
of 1000 Btu/ft^ (37.5 MJ/m^). 

Solution 

( 1 ) Maximum gas demand for oudet A: 

r> . /ratine; plate input, or \ 

Consumption -r , , °r . „ 1 F 

'^ ^lable 5.4.2.1 u necessary j 



Btu of gas 
35,000 Btu/hr rating 



1,000 Btu/ft 
Maximum gas demand for outlet B: 

Consumption _ 75,000 
Btu of gas ~ 1,000 



= 35 ftVhr = 35 cfli 



:75cfti 



2002 Edition 



54-122 



NATIONAL FUEL GAS CODE 



ANSIZ223.1-122 




10 20 30 40 5060 80100 200 400 600 800 1-1000 2000 

Gas volume (standard ft^r gas SpGr = 0.60) 



4000 6000 10,000 



FIGURE C.6(a) Capacity of Natural Gas Piping, Low Pressure (0.60 in. w.c). 



Maximum gas demand for oudet C: 

Consumption _ 35,000 _ op. r. 
Btuofgas " 1,000 ~ 

Maximum gas demand for oudet D: 

Consumption 100,000 ,^^ _ 

= = 100 cm 

Btuofgas 1,000 

(2) The length of pipe from the point of delivery to the most 
remote oudet (A) is 60 ft (18.3 m). This is the only dis- 
tance used. 

(3) Using the row marked 60 ft (18.3 m) in Table 12.2: 

(a) Oudet A, supplying 35 cfh (0.99 m^/hr), requires 
% in. pipe. 

(b) Oudet B, supplying 75 cfh (2.12 m^/hr), requires 
% in. pipe. 

(c) Section 1, supplying outlets A and B, or 110 cfh 
(3.11 m^/hr), requires % in. pipe. 

(d) Section 2, supplying oudets C and D, or 135 cfh 
(3.82 m^'/hr), requires % in. pipe. 

(e) Section 3, supplying outlets A, B, C, and D, or 245 cfh 
(6.94 m^/hr), requires 1 in. pipe. 

(4) If a different gravity factor is applied to this example, the 
values in the row marked 60 ft (18.3 m) of Table 12.2 
would be mukiplied by the appropriate multiplier from 
Table C.2.4 and the resulting cubic feet per hour values 
would be used to size the piping. 



C.7.2 Example 2 — Hybrid or Dual Pressure Systems. Deter- 
mine the required CSST size of each secdon of the piping 
system shown in Figure C.7.2, with a designated pressure drop 
of 1 psi (6.9 kPa) for the 2 psi (13.8 kPa) secdon and 3 in. w.c. 
(0.75 kPa) pressure drop for the 10 in. w.c. (2.49 kPa) section. 
The gas to be used has 0.60 specific gravity and a heating value 
of 1000 Btu/ft^ (37.5 MJ/m^). 

Solution 

(1) Size 2 psi (13.8 kPa) line using Table 12.17. 

(2) Size 10 in. w.c. (2.5 kPa) lines using Table 12.15. 

(3) Using the following steps, determine if sizing tables can 
be used: 

(a) Total gas load shown in Figure C.7.2 equals 110 chf 
(3.11 mVhr). 

(b) Determine pressure drop across regulator (see notes 
in Table 12.17). 

(c) If pressure drop across regulator exceeds % psi 
(5.2 kPa), Table 12.17 cannot be used. Note that if 
pressure drop exceeds Vi psi (5.2 kPa), then a 
larger regulator must be selected or an alternative 
sizing method must be used. 

(d) Pressure drop across the line regulator [for 110 cfh/ 
(3.11 m^/hr)] is 4 in. w.c. (0.99 kPa) based on manu- 
facturer's performance data. 

(e) Assume the CSST manufacturer has tubing sizes or 
EHDsofl3, 18, 23, and30. 

(4) From Section A [2 psi (13.8 kPa) zone]: 



2002 Edition 



ANSIZ223.1-123 



ANNEX C 



54-123 



Index number = 



Dist. 



(100) 



Dist. = Eq. length, ft 

Pf = Initial press, abs. psi 

P2 = Final press, abs. psi 











3/4" 






1 


11/4" 11/2° 




2 




21/2" 3" 




4" 






5" 




6" 


8" 


10" 




12 


' 






















/ 


1 






/ 




7 


1 




/ 










1 


/ 


/ 






' 






















/ 


/ 


/ 






f 




' 


1 




f 




i 








f 


/ 




j 








b 


















/ 


/ 




i 






/ 


/ 


/ 










/ 






/ 




/ 








/ 






i 








1 




/ 


/ 




/ 






r 


/ 


/ 




> 






i 






f 


i 
















/ 






i 






/ 


/ 




f 




1 




/ 


/ 




/ 






/ 




J 




/ 
















/ 






1 






/ > 


1 


/ 




J 


t 




/ 


/ 




/ 




/ 






/ 




1 










3 
2 

100 
9 




/ 


f 




1 








// 




/ 




/ 






f 

f 1 


f 


/ 




/ 








/ 


/ 














/ 




/ 








/ 


1 / 


/ 




/ 






/ 




J 


/ 


/i 


1 








^ 


1 














1 


y 


' 




1 


1 




1 


/ 

J 


/ 




J 


1 


f 


/ 


/ 


h 


/ 






/ 
/ 


1 1 


/ 
















i 
















/ 






f 






/ i 




f 




























/ 












/ 


/ 


/ 




i 








/ 


J 








/ 




















8 




/ 












' 


/ 


/ 




/ 








1 f 


/ 








f 




















7 
6 
5 

4 
3 

2 

10 
9 




/ 










1 




/ 


/ 




/ 






1 




/ 






> 
























/ 








1 






1 


/ 


} 








i 


1 


/ 






/ 






t / 


















f 


1 






1 






/ 1 




/ 








( 


/ 


/ 




/ 






/ 






















/ 




1 








1 / 




/ 






1 




/ y 






/ 






/ 




















1 


1 


/ 








/ 


f / 


/ 






1 






/ / 




1 




y 


1 




/ 


















A 


} 


f 


J 


1 


k 




1 1 


/ 


1 


/ 




/ 


t 
f 


/ 


/ 


f 


/ 


/ 


1 


/ 
/ 




















i 






I 








/ 




/ 






f 






/ 


J 




























/ 






f 








/ 




/ 




1 






r 


/ 


/ 




i 


























/ 




i 






1 




/ 


y 






/ 




1 


J 




/ 




f 






















/ 
6 
5 

4 
3 

2 

1 n 




/ 




/ 






f 




/ 


/ 






r 




f 


/ 




f 




























/ 




f 




1 






/ 


/ 




/ 






1 


/ 


/ 




1 


























f 


} 




J 


f 






/ 


/ 




/ 




} 




/ 


/ 




1 




























/ 




r 








t / 


f 


/ 




I 


f 




1 


/ 


/ 




























/ 




/ 






/ 


/ 


/ 


/ 


/ 


/ 


f 






/ / 


f 


/ 


























^ / 


/ 

i 


/ 




1 


1 


/ 




/ 


A 


/^ 


/ 






1 
1- 


'7 


A 








_ 












_ 









10,000 



1 ,000,000 



10,000,000 



Gas volume (standard ft^/hr gas specific gravity = 0.60) 
FIGURE C.6(b) Capacity of Natural Gas Piping, High Pressure (1.5 psi and above). 



Section 3 



I 
I 

I 
10ft^ 



Outlet C • — 
40 gal automatic 
water heater 
35,000 Btu/hr 



20 ft 



Outlet D 
furnace 
100,000 Btu/hr 



Section 2 
f 20 ft 

Section 1 
10ft 



15ft 



Point of 
delivery 



^15ft 



5 ft 



Outlet A 
clothes dryer 
35,000 Btu/hr 



Outlet B 
range/oven unit 
75,000 Btu/hr 

For SI units, 1 ft = 0.305 m, 1 gal = 3.785 L, 1000 Btu/hr = 0.293 kW. 

FIGURE C.7. 1 Piping Plan Showing a Steel Piping System. 

(a) Determine distance from meter to regulator - 100 ft 
(30.48 m). 

(b) Determine total load supplied by A = 110 cfh (3.11 
m^/hr) (furnace + water heater + dryer) . 



(c) Table 12.17 shows that EHD size 18 should be used. 
Note that it is not unusual to oversize the supply line 
by 25 to 50 percent of the as-installed load. EHD size 
18 has a capacity of 189 cfh (5.35 mVhr). 

(5) From Section B (low pressure zone): 

(a) Distance from regulator to furnace is 15 ft (4.57 m). 

(b) Load is 60 cfh (1.70 mVhr). 

(c) Table 12.15 shows that EHD size 13 should be used. 

(6) From Section C (low pressure zone): 

(a) Distance from regulator to water heater is 10 ft (3 m) . 

(b) Load is 30 cfh (0.85 mVhr). 

(c) Table 12.15 shows that EHD size 13 should be used. 

(7) From Section D (low pressure zone): 

(a) Distance from regulator to dryer is 25 ft (7.62 m). 

(b) Load is 20 cfh (0.57 mVhr). 

(c) Table 12.15 shows that EHD size 13 should be used. 

C.7.3 Example 3 — Branch Length Method. Determine the 
required semi-rigid copper tubing size of each section of the 
piping system shown in Figure C.7.3, with a designated pres- 
sure drop of 1 in. w.c. (250 Pa) (using the Branch Length 
Method). The gas to be used has 0.60 specific gravity and a 
heating value of 1,000 Btu/ft^ (37.5 MJ/m^). 

Solution 

(1) Section A: 

(a) The length of tubing from the point of delivery to the 
most remote appliance is 50 ft (15 m) , A + C. 



2002 Edition 



54-124 



NATIONAL FUEL GAS CODE 



ANSIZ223.1-124 



2psig 

Gas meter 

110cfh 




Length of runs: 
A = 100 ft 
B = 15ft 
C = 10ft 
D = 25ft 



Key: 

iiii Manifold 
X Shut-off valve 
[>]<] Pressure regulator 
[m1 Gas meter 



FIGURE C.7.2 Piping Plan Showing a CSST System. 



(b) Use this longest length to size Sections A and C. 

(c) Using the row marked 50 ft (15 m) in Table 12.9, 
Section A supplying 220 cfh (6.23 m^/hr) for four 
appliances requires 1 in. tubing. 

(2) Section B: 

(a) The length of tubing from the point of delivery to the 
range/oven at the end of Section B is 30 ft (9.14 m), 
A+B. 

(b) Use this branch length to size Section B only. 

(c) Using the row marked 30 ft (9.14 m) in Table 12.9, 
Section B supplying 75 cfh (2.12 mVhr) for the 
range/oven requires V2 in. tubing. 

(3) Section C: 

(a) The length of tubing from the point of delivery to the 
dryer at the end of Section C is 50 ft (15 m), A+ C. 

(b) Use this branch length (which is also the longest 
length) to size Section C. 

(c) Using the row marked 50 ft (15 m) in Table 12.9, 
Section C supplying 30 cfh (0.85 m^/hr) for the dryer 
requires % in. tubing. 

(4) Section D: 

(a) The length of tubing from the point of delivery to the 
water heater at the end of Section D is 30 ft (9.14 m), 
A+D. 

(b) Use this branch length to size Section D only. 

(c) Using the row marked 30 ft (9.14 m) in Table 12.9, 
Section D supplying 35 cfh (34.69 m^/hr) for the wa- 
ter heater requires % in. tubing. 

(5) Section E: 

(a) The length of tubing from the point of delivery to the 
furnace at the end of Section E is 30 ft (9. 14 m) , A+ E. 

(b) Use this branch length to size Section E only. 

(c) Using the row marked 30 ft (9.14 m) in Table 12.9, 
Section E supplying 80 cfh (0.99 m^/hr) for the fur- 
nace requires V2 in. tubing. 



00 Range/oven 
00 75 cfh 



Section A 



220 cfh 



^. Section B 

__JJ~^ Section 
Section E W(^ 



Section C 



D 

Water 
heater 
35 cfh 



Furnace 
80 cfh 



Dryer 
30 cfh 



Length of runs: 
A = 20 ft 
B = 10ft 
C = 30ft 
D = 10ft 
E = 10ft 



Key: 



Manifold 
X Shut-off valve 
[m] Gas meter 
Total gas load = 220 cfh 



FIGURE C.7.3 Piping Plan Showing a Copper Tubing System. 



C.7.4 Example 4 — ModiHcation to Existing Piping System. 

Determine the required CSST size for Section G (retrofit ap- 
plication) of the piping system shown in Figure C.7.4, with a 
designated pressure drop of 0.50 in. w.c. (125 Pa) using the 
Branch Length Method. The gas to be used has 0.60 specific 
gravity and a heating value of 1,000 Btu/ft^ (37.5 MJ/m^). 

Solution 

(1) The length of pipe and CSST from the point of delivery to 
the retrofit appliance (barbecue) at the end of Section G 
is40ft(12.19m),A+B + G. 

(2) Use this branch length to size Section G. 

(3) Assume the CSST manufacturer has tubing sizes or EHDs 
ofl3, 18, 23, andSO. 













Barbecue 












40 cfh 






R71 


















1 


Section G 


M 




g 
Section A Section B j 


Section C 




\ \ \ 








Section E 






Section F 


> 


f 

\ 






) 


^ /^ Section D 










Water > 


V 








heater ^ 






Furnace 30 cfh 










'*"<^^" Range/oven 






75 cfh 



Length of runs: 
A=15ft E = 5ft 
B = 10ft F = 10ft 
C = 15ft G = 15ft 
D = 20ft 



Key: 

X Shut-off valve 

[m] Gas meter 



FIGURE C.7.4 Piping Plan Showing Modification to an Exist- 
ing Piping System. 



2002 Edition 



ANSIZ223.1-125 



ANNEXE 



54-125 



(4) Using the row marked 40 ft (12.19 m) in Table 12.14, 
Section G supplying 40 cfh (1.13 m^/hr) for the barbecue 
requires EHD 18 CSST. 

(5) The sizing of Sections A, B, F, and E must be checked to 
ensure adequate gas carrying capacity since an appliance 
has been added to the piping system. See C.7.1 for details. 



Annex D Suggested Method of Checking for Leakage 

This annex is not a part of the requirements of this code but is 
included for informational purposes only. 

D.l Use of Lights. Artificial illumination used in connection 
with a search for gas leakage should be restricted to battery- 
operated flashlights (preferably of the safety type) or ap- 
proved safety lamps. In searching for leaks, electric switches 
should not be operated. If electric lights are already turned 
on, they should not be turned off. 

D.2 Testing for Leakage Using the Gas Meter. Immediately 
prior to the test, it should be determined that the meter is in 
operating condition and has not been bypassed. 

Checking for leakage can be done by carefully watching the 
test dial of the meter to determine whether gas is passing 
through the meter. To assist in observing any movement of the 
test hand, wet a small piece of paper and paste its edge directly 
over the centerline of the hand as soon as the gas is turned on. 
This observation should be made with the test hand on the 
upstroke. Table D.2 can be used for determining the length of 
observation time. 

Table D.2 Test Observation Times for Various Meter Dials 



Dial Styles 
(ft^) 



Test Time 
(min) 



1/4 
1/2 



1 

2 

5 

10 



5 

5 

7 

10 

20 

30 



For SI units, 1 ft^ = 0.028 m^. 



LP-Gas system being placed back in service should include 
all regulators, including appliance regulators, and control 
valves in the system. Accordingly, each individual equipment 
shutoff valve should be supplying pressure to its appliance 
for the leak check. This check will prove the integrity of the 
100 percent pilot shutoff of each gas valve so equipped, so 
the manual gas cock of each gas valve incorporating a 
100 percent pilot shutoff should be in the on position. Pilots 
not incorporating a 100 percent pilot shutoff valve and all 
manual gas valves not incorporating safety shutoff systems 
are to be placed in the off position prior to leak checking, by 
using one of the following methods: 

(a) By inserting a pressure gauge between the container 
gas shutoff valve and the first regulator in the system, 
admitting full container pressure to the system and 
then closing the container shutoff valve. Enough gas 
should then be released from the system to lower the 
pressure gauge reading by 10 psi (69 kPa). The sys- 
tem should then be allowed to stand for 3 minutes 
without showing an increase or a decrease in the pres- 
sure gauge reading. 

(b) For systems serving appliances that receive gas at pres- 
sures of ¥2 psi (3.5 kPa) or less, by inserting a water 
manometer or pressure gauge into the system down- 
stream of the final system regulator, pressurizing the 
system with either fuel gas or air to a test pressure of 
9 in. w.c. ± 1/2 in. w.c. (2.2 kPa ± 0.1 kPa), and observ- 
ing the device for a pressure change. If fuel gas is 
used as a pressure source, it is necessary to pressurize 
the system to full operating pressure, close the con- 
tainer service valve, and then release enough gas 
from the system through a range burner valve or 
other suitable means to drop the system pressure to 
9 in. w.c. ± V2 in. w.c. (2.2 kPa ± 0.1 kPa). This ensures 
that all regulators in the system are unlocked and that 
a leak anywhere in the system is communicated to the 
gauging device. The gauging device should indicate 
no loss or gain of pressure for a period of 3 minutes. 

D.4 When Leakage Is Indicated. If the meter test hand moves 
or a pressure drop on the gauge is noted, all equipment or 
oudets supplied through the system should be examined to 
see whether they are shut off and do not leak. If they are found 
tight, there is a leak in the piping system. 



In case careful observation of the test hand for a sufficient 
length of time reveals no movement, the piping should be 
purged and a small gas burner turned on and lighted and the 
hand of the test dial again observed. If the dial hand moves (as 
it should) , it will show that the meter is operating properly. If 
the test hand does not move or register flow of gas through the 
meter to the small burner, the meter is defective and the gas 
should be shut off and the serving gas supplier notified. 

D.3 Testing for Leakage not Using a Meter. This test can be 
done by one of the following methods: 

(1) For Any Gas System. To an appropriate checkpoint, attach 
a manometer or pressure gauge between the inlet to the 
piping system and the first regulator in the piping system, 
momentarily turn on the gas supply, and observe the 
gauging device for pressure drop with the gas supply shut 
off. No discernible drop in pressure should occur during 
a period of 3 minutes. 

(2) For Gas Systems Using Undiluted Liquefied Petroleum Gas System 
Preparation for Propane. A leak check performed on an 



Annex E Suggested Emei^ency Procedure 
for Gas Leaks 

This annex is not a part of the requirements of this code but is 
included for informational purposes only. 

E.l Where an investigation discloses a concentration of gas 
inside of a building, it is suggested the following immediate 
actions be taken: 

(1) Clear the room, building, or area of all occupants. Do not 
re-enter the room, building, or area until the space has 
been determined to be safe. 

(2) Use every practical means to eliminate sources of ignition. 
Take precautions to prevent smoking, striking matches, 
operating electrical switches or devices, opening furnace 
doors, and so on. If possible, cut off all electric circuits at a 
remote source to eliminate operation of automatic 
switches in the dangerous area. Safety flashlights designed 
for use in hazardous atmospheres are recommended for 
use in such emergencies. 



2002 Edition 



54-126 



NATIONAL FUEL GAS CODE 



ANSIZ223.1-126 



(3) Notify all personnel in the area and the gas supplier from 
a telephone remote from the area of the leak. 

(4) Ventilate the affected portion of the building by opening 
windows and doors. 

(5) Shut off the supply of gas to the areas involved. 

(6) Investigate other buildings in the immediate area to de- 
termine the presence of escaping gas therein. 



Annex F Flow of Gas Through Fixed Orifices 

This annex is not a part of the requirements of this code but is 
included for informational purposes only. 

El Use of Orifice Tables. 

F.1.1 To Check Burner Input not Using a Meter. Gauge the 
size of the burner orifice and determine flow rate at sea level 
from Table F.l, Utility Gases (cubic feet per hour), or from 



Table F.l Utility Gases (cubic feet per hour at sea level) 



Orifice 
or 








Pressure at Orifice (in. 


w.c.) 








Drill 




















Size 


3 


3.5 


4 


5 


6 


7 


8 


9 


10 


80 


0.48 


0.52 


0.55 


0.63 


0.69 


0.73 


0.79 


0.83 


0.88 


79 


0.55 


0.59 


0.64 


0.72 


0.80 


0.84 


0.90 


0.97 


1.01 


78 


0.70 


0.76 


0.78 


0.88 


0.97 


1.04 


1.10 


1.17 


1.24 


77 


0.88 


0.95 


0.99 


1.11 


1.23 


1.31 


1.38 


1.47 


1.55 


76 


1.05 


1.13 


1.21 


1.37 


1.52 


1.61 


1.72 


1.83 


1.92 


75 


1.16 


1.25 


1.34 


1.52 


1.64 


1.79 


1.91 


2.04 


2.14 


74 


1.33 


1.44 


1.55 


1.74 


1.91 


2.05 


2.18 


2.32 


2.44 


73 


1.51 


1.63 


1.76 


1.99 


2.17 


2.32 


2.48 


2.64 


2.78 


72 


1.64 


1.77 


1.90 


2.15 


2.40 


2.52 


2.69 


2.86 


3.00 


71 


1.82 


1.97 


2.06 


2.33 


2.54 


2.73 


2.91 


3.11 


3.26 


70 


2.06 


2.22 


2.39 


2.70 


2.97 


3.16 


3.38 


3.59 


3.78 


69 


2.25 


2.43 


2.61 


2.96 


3.23 


3.47 


3.68 


3.94 


4.14 


68 


2.52 


2.72 


2.93 


3.26 


3.58 


3.88 


4.14 


4.41 


4.64 


67 


2.69 


2.91 


3.12 


3.52 


3.87 


4.13 


4.41 


4.69 


4.94 


66 


2.86 


3.09 


3.32 


3.75 


4.11 


4.39 


4.68 


4.98 


5.24 


65 


3.14 


3.39 


3.72 


4.28 


4.62 


4.84 


5.16 


5.50 


5.78 


64 


3.41 


3.68 


4.14 


4.48 


4.91 


5.23 


5.59 


5.95 


6.26 


63 


3.63 


3.92 


4.19 


4.75 


5.19 


5.55 


5.92 


6.30 


6.63 


62 


3.78 


4.08 


4.39 


4.96 


5.42 


5.81 


6.20 


6.59 


6.94 


61 


4.02 


4.34 


4.66 


5.27 


5.77 


6.15 


6.57 


7.00 


7.37 


60 


4.21 


4.55 


4.89 


5.52 


5.95 


6.47 


6.91 


7.35 


7.74 


59 


4.41 


4.76 


5.11 


5.78 


6.35 


6.78 


7.25 


7.71 


8.11 


58 


4.66 


5.03 


5.39 


6.10 


6.68 


7.13 


7.62 


8.11 


8.53 


57 


4.84 


5.23 


5.63 


6.36 


6.96 


7.44 


7.94 


8.46 


8.90 


56 


5.68 


6.13 


6.58 


7.35 


8.03 


8.73 


9.32 


9.92 


10.44 


55 


7.11 


7.68 


8.22 


9.30 


10.18 


10.85 


11.59 


12.34 


12.98 


54 


7.95 


8.59 


9.23 


10.45 


11.39 


12.25 


13.08 


13.93 


14.65 


53 


9.30 


10.04 


10.80 


12.20 


13.32 


14.29 


15.27 


16.25 


17.09 


52 


10.61 


11.46 


12.31 


13.86 


15.26 


16.34 


17.44 


18.57 


19.53 


51 


11.82 


12.77 


13.69 


15.47 


16.97 


18.16 


19.40 


20.64 


21.71 


50 


12.89 


13.92 


14.94 


16.86 


18.48 


19.77 


21.12 


22.48 


23.65 


49 


14.07 


15.20 


16.28 


18.37 


20.20 


21.60 


23.06 


24.56 


25.83 


48 


15.15 


16.36 


17.62 


19.88 


21.81 


23.31 


24.90 


26.51 


27.89 


47 


16.22 


17.52 


18.80 


21.27 


23.21 


24.93 


26.62 


28.34 


29.81 


46 


17.19 


18.57 


19.98 


22.57 


24.72 


26.43 


28.23 


30.05 


31.61 


45 


17.73 


19.15 


20.52 


23.10 


25.36 


27.18 


29.03 


30.90 


32.51 


44 


19.45 


21.01 


22.57 


25.57 


27.93 


29.87 


31.89 


33.96 


35.72 


43 


20.73 


22.39 


24.18 


27.29 


29.87 


32.02 


34.19 


36.41 


38.30 


42 


23.10 


24.95 


26.50 


29.50 


32.50 


35.24 


37.63 


40.07 


42.14 


41 


24.06 


25.98 


28.15 


31.69 


34.81 


37.17 


39.70 


42.27 


44.46 



2002 Edition 



ANSIZ223.1-127 



ANNEX F 



54-127 



Table F.l Continued 



Orifice 




















or 








Pressure at Orifice (in. 


w.c.) 








Drill 




















Size 


3 


3.5 


4 


5 


6 


7 


8 


9 


10 


40 


25.03 


27.03 


29.23 


33.09 


36.20 


38.79 


41.42 


44.10 


46.38 


39 


26.11 


28.20 


30.20 


34.05 


37.38 


39.97 


42.68 


45.44 


47.80 


38 


27.08 


29.25 


31.38 


35.46 


38.89 


41.58 


44.40 


47.27 


49.73 


37 


28.36 


30.63 


32.99 


37.07 


40.83 


43.62 


46.59 


49.60 


52.17 


36 


29.76 


32.14 


34.59 


39.11 


42.76 


45.77 


48.88 


52.04 


54.74 


35 


32.36 


34.95 


36.86 


41.68 


45.66 


48.78 


52.10 


55.46 


58.34 


34 


32.45 


35.05 


37.50 


42.44 


46.52 


49.75 


53.12 


56.55 


59.49 


33 


33.41 


36.08 


38.79 


43.83 


48.03 


51.46 


54.96 


58.62 


61.55 


32 


35.46 


38.30 


40.94 


46.52 


50.82 


54.26 


57.95 


61.70 


64.89 


31 


37.82 


40.85 


43.83 


49.64 


54.36 


58.01 


61.96 


65.97 


69.39 


30 


43.40 


46.87 


50.39 


57.05 


62.09 


66.72 


71.22 


75.86 


79.80 


29 


48.45 


52.33 


56.19 


63.61 


69.62 


74.45 


79.52 


84.66 


89.04 


28 


51.78 


55.92 


59.50 


67.00 


73.50 


79.50 


84.92 


90.39 


95.09 


27 


54.47 


58.83 


63.17 


71.55 


78.32 


83.59 


89.27 


95.04 


99.97 


26 


56.73 


61.27 


65.86 


74.57 


81.65 


87.24 


93.17 


99.19 


104.57 


25 


58.87 


63.58 


68.22 


77.14 


84.67 


90.36 


96.50 


102.74 


108.07 


24 


60.81 


65.67 


70.58 


79.83 


87.56 


93.47 


99.83 


106.28 


111.79 


23 


62.10 


67.07 


72.20 


81.65 


89.39 


94.55 


100.98 


107.49 


113.07 


22 


64.89 


70.08 


75.21 


85.10 


93.25 


99.60 


106.39 


113.24 


119.12 


21 


66.51 


71.83 


77.14 


87.35 


95.63 


102.29 


109.24 


116.29 


122.33 


20 


68.22 


73.68 


79.08 


89.49 


97.99 


104.75 


111.87 


119.10 


125.28 


19 


72.20 


77.98 


83.69 


94.76 


103.89 


110.67 


118.55 


125.82 


132.36 


18 


75.53 


81.57 


87.56 


97.50 


108.52 


116.03 


123.92 


131.93 


138.78 


17 


78.54 


84.82 


91.10 


103.14 


112.81 


120.33 


128.52 


136.82 


143.91 


16 


82.19 


88.77 


95.40 


107.98 


118.18 


126.78 


135.39 


144.15 


151.63 


15 


85.20 


92.02 


98.84 


111.74 


122.48 


131.07 


139.98 


149.03 


156.77 


14 


87.10 


94.40 


100.78 


114.21 


124.44 


133.22 


142.28 


151.47 


159.33 


13 


89.92 


97.11 


104.32 


118.18 


128.93 


138.60 


148.02 


157.58 


165.76 


12 


93.90 


101.41 


108.52 


123.56 


135.37 


143.97 


153.75 


163.69 


172.13 


11 


95.94 


103.62 


111.31 


126.02 


137.52 


147.20 


157.20 


167.36 


176.03 


10 


98.30 


106.16 


114.21 


129.25 


141.82 


151.50 


161.81 


172.26 


181.13 


9 


100.99 


109.07 


117.11 


132.58 


145.05 


154.71 


165.23 


175.91 


185.03 


8 


103.89 


112.20 


120.65 


136.44 


149.33 


160.08 


170.96 


182.00 


191.44 


7 


105.93 


114.40 


123.01 


139.23 


152.56 


163.31 


174.38 


185.68 


195.30 


6 


109.15 


117.88 


126.78 


142.88 


156.83 


167.51 


178.88 


190.46 


200.36 


5 


111.08 


119.97 


128.93 


145.79 


160.08 


170.82 


182.48 


194.22 


204.30 


4 


114.75 


123.93 


133.22 


150.41 


164.36 


176.18 


188.16 


200.25 


210.71 


3 


119.25 


128.79 


137.52 


156.26 


170.78 


182.64 


195.08 


207.66 


218.44 


2 


128.48 


138.76 


148.61 


168.64 


184.79 


197.66 


211.05 


224.74 


235.58 


1 


136.35 


147.26 


158.25 


179.33 


194.63 


209.48 


223.65 


238.16 


250.54 



For SI units, 1 Btu/hr = 0.293 W, 1 ft^ = 0.028 m^ 1 ft = 0.305 m, 1 in. w.c. = 249 Pa. 
Notes: 

1. Specific gravity = 0.60; orifice coefilcient = 0.90. 

2. For utility gases of another specific gravity, select multiplier from Table F.3. For altitudes above 2000 ft, first select the equivalent orifice size at sea 
level from Table F.4. 



2002 Edition 



54-128 



NATIONAL FUEL GAS CODE 



ANSIZ223.1-128 



Table E2 LP-Gases (Btu 


per hour at sea level) 


Table E2 Continued 








Orifice or 






Orifice or 










DriU Size 


Propane 


Butane 


Drill Size 




Propane 




Butane 


0.008 


519 


589 


40 




78,029 




88,459 


0.009 


656 


744 


39 




80,513 




91,215 


0.010 


812 


921 


38 




83,721 




94,912 


0.011 


981 


1,112 


37 




87,860 




99,605 


0.012 


1,169 


1,326 


36 




92,207 




104,532 


80 


1,480 


1,678 


35 




98,312 




111,454 


79 


1,708 


1,936 


34 




100,175 




113,566 


78 


2,080 


2,358 


33 




103,797 




117,672 


77 


2,629 


2,980 


32 




109,385 




124,007 


76 


3,249 


3,684 


31 




117,043 




132,689 


75 


3,581 


4,059 


30 




134,119 




152,046 


74 


4,119 


4,669 


29 




150,366 




170,466 


73 


4,678 


5,303 


28 




160,301 




181,728 


72 


5,081 


5,760 


27 




168,580 




191,114 


71 


5,495 


6,230 


26 




175,617 




199,092 


70 


6,375 


7,227 


25 




181,619 




205,896 


69 


6,934 


7,860 


24 




187,828 




212,935 


68 


7,813 


8,858 


23 




192,796 




218,567 


67 


8,320 


9,433 


22 




200,350 




227,131 


66 


8,848 


10,031 


21 




205,525 




232,997 


65 


9,955 


11,286 


20 




210,699 




238,863 


64 


10,535 


11,943 


19 




223,945 




253,880 


63 
62 


11,125 
11,735 


12,612 
13,304 


18 




233,466 




264,673 












61 


12,367 


14,020 


Notes: 

L Btu per cubic foot 

2. Specific gravity 

3. Pressure at orifice, 

4. Orifice coefficient 


in. w.c. 




Propane 

2,516 

1.52 

11 

0.9 




60 
59 

58 

57 


13,008 
13,660 
14,333 
15,026 


14,747 
15,486 
16,249 
17,035 


Butane 

3,280 

2.01 

11 

0.9 


56 


17,572 


19,921 


5. For altitudes above 2000 ft (610 m), first select th( 


z equivalent 


55 


21,939 


24,872 












54 
53 

52 


24,630 
28,769 
32,805 
36,531 


27,922 
32,615 
37,190 
41,414 


Table F.3 Multipli 
Gravity 


ers for 


Utility Gases of Another Specific 


51 


Specific 

Gravity Multipli 


Specific 
er Gravity 




50 


39,842 
43,361 
46,983 
50,088 
53,296 


45,168 
49,157 
53,263 
56,783 
60,420 


Multiplier 


49 
48 
47 
46 


0.45 
0.50 
0.55 
0.60 
0.65 
0.70 
0.75 
0.80 
0.85 
0.90 


1.155 
1.095 
1.045 
1.000 
0.961 
0.926 
0.894 
0.866 
0.840 
0.817 




0.95 
1.00 
1.05 
1.10 
1.15 
1.20 
1.25 
1.30 
1.35 
1.40 


0.795 
0.775 
0.756 
0.739 


45 
44 
43 
42 
41 


54,641 
60,229 
64,369 
71,095 
74,924 


61,944 
68,280 
72,973 
80,599 
84,940 


0.722 
0.707 
0.693 
0.679 
0.667 
0.655 











2002 Edition 



ANSIZ223.1-129 



ANNEX F 



54-129 



Table F.4 


Equivalent 


Orifice Sizes at 


High Altitudes (includes 4% input reduction for each 1000 ft) 






Orifice 








Orifice Size 


Required at Other Elevations 








Size at 






































Sea Level 


2000 


3000 


4000 


5000 


6000 


7000 


8000 


9000 


10,000 


1 


2 


2 


3 


3 


4 


5 


7 


8 


10 


2 


3 


3 


4 


5 


6 


7 


9 


10 


12 


3 


4 


5 


7 


8 


9 


10 


12 


13 


15 


4 


6 


7 


8 


9 


11 


12 


13 


14 


16 


5 


7 


8 


9 


10 


12 


13 


14 


15 


17 


6 


8 


9 


10 


11 


12 


13 


14 


16 


17 


7 


9 


10 


11 


12 


13 


14 


15 


16 


18 


8 


10 


11 


12 


13 


13 


15 


16 


17 


18 


9 


11 


12 


12 


13 


14 


16 


17 


18 


19 


10 


12 


13 


13 


14 


15 


16 


17 


18 


19 


11 


13 


13 


14 


15 


16 


17 


18 


19 


20 


12 


13 


14 


15 


16 


17 


17 


18 


19 


20 


13 


15 


15 


16 


17 


18 


18 


19 


20 


22 


14 


16 


16 


17 


18 


18 


19 


20 


21 


23 


15 


16 


17 


17 


18 


19 


20 


20 


22 


24 


16 


17 


18 


18 


19 


19 


20 


22 


23 


25 


17 


18 


19 


19 


20 


21 


22 


23 


24 


26 


18 


19 


19 


20 


21 


22 


23 


24 


26 


27 


19 


20 


20 


21 


22 


23 


25 


26 


27 


28 


20 


22 


22 


23 


24 


25 


26 


27 


28 


29 


21 


23 


23 


24 


25 


26 


27 


28 


28 


29 


22 


23 


24 


25 


26 


27 


27 


28 


29 


29 


23 


25 


25 


26 


27 


27 


28 


29 


29 


30 


24 


25 


26 


27 


27 


28 


28 


29 


29 


30 


25 


26 


27 


27 


28 


28 


29 


29 


30 


30 


26 


27 


28 


28 


28 


29 


29 


30 


30 


30 


27 


28 


28 


29 


29 


29 


30 


30 


30 


31 


28 


29 


29 


29 


30 


30 


30 


30 


31 


31 


29 


29 


30 


30 


30 


30 


31 


31 


31 


32 


30 


30 


31 


31 


31 


31 


32 


32 


33 


35 


31 


32 


32 


32 


33 


34 


35 


36 


37 


38 


32 


33 


34 


35 


35 


36 


36 


37 


38 


40 


33 


35 


35 


36 


36 


37 


38 


38 


40 


41 


34 


35 


36 


36 


37 


37 


38 


39 


40 


42 


35 


36 


36 


37 


37 


38 


39 


40 


41 


42 


36 


37 


38 


38 


39 


40 


41 


41 


42 


43 


37 


38 


39 


39 


40 


41 


42 


42 


43 


43 


38 


39 


40 


41 


41 


42 


42 


43 


43 


44 


39 


40 


41 


41 


42 


42 


43 


43 


44 


44 


40 


41 


42 


42 


42 


43 


43 


44 


44 


45 


41 


42 


42 


42 


43 


43 


44 


44 


45 


46 


42 


42 


43 


43 


43 


44 


44 


45 


46 


47 


43 


44 


44 


44 


45 


45 


46 


47 


47 


48 


44 


45 


45 


45 


46 


47 


47 


48 


48 


49 


45 


46 


47 


47 


47 


48 


48 


49 


49 


50 


46 


47 


47 


47 


48 


48 


49 


49 


50 


50 


47 


48 


48 


49 


49 


49 


50 


50 


51 


51 


48 


49 


49 


49 


50 


50 


50 


51 


51 


52 


49 


50 


50 


50 


51 


51 


51 


52 


52 


52 


50 


51 


51 


51 


51 


52 


52 


52 


53 


53 



2002 Edition 



54-130 



NATIONAL FUEL GAS CODE 



ANSIZ223.1-130 



Table F.4 Continued 



Orifice 








Orifice Size 


Required at Other Elevations 








C *^ r» + 




















Sea Level 


2000 


3000 


4000 


5000 


6000 


7000 


8000 


9000 


10,000 


51 


51 


52 


52 


52 


52 


53 


53 


53 


54 


52 


52 


53 


53 


53 


53 


53 


54 


54 


54 


53 


54 


54 


54 


54 


54 


54 


55 


55 


55 


54 


54 


55 


55 


55 


55 


55 


56 


56 


56 


55 


55 


55 


55 


56 


56 


56 


56 


56 


57 


56 


56 


56 


57 


57 


57 


58 


59 


59 


60 


57 


58 


59 


59 


60 


60 


61 


62 


63 


63 


58 


59 


60 


60 


61 


62 


62 


63 


63 


64 


59 


60 


61 


61 


62 


62 


63 


64 


64 


65 


60 


61 


61 


62 


63 


63 


64 


64 


65 


65 


61 


62 


62 


63 


63 


64 


65 


65 


66 


66 


62 


63 


63 


64 


64 


65 


65 


66 


66 


67 


63 


64 


64 


65 


65 


65 


66 


66 


67 


68 


64 


65 


65 


65 


66 


66 


66 


67 


67 


68 


65 


65 


66 


66 


66 


67 


67 


68 


68 


69 


66 


67 


67 


68 


68 


68 


69 


69 


69 


70 


67 


68 


68 


68 


69 


69 


69 


70 


70 


70 


68 


68 


69 


69 


69 


70 


70 


70 


71 


71 


69 


70 


70 


70 


70 


71 


71 


71 


72 


72 


70 


70 


71 


71 


71 


71 


72 


72 


73 


73 


71 


72 


72 


72 


73 


73 


73 


74 


74 


74 


72 


73 


73 


73 


73 


74 


74 


74 


74 


75 


73 


73 


74 


74 


74 


74 


75 


75 


75 


76 


74 


74 


75 


75 


75 


75 


76 


76 


76 


76 


75 


75 


76 


76 


76 


76 


77 


77 


77 


77 


76 


76 


76 


77 


77 


77 


77 


77 


77 


77 


77 


77 


77 


77 


78 


78 


78 


78 


78 


78 


78 


78 


78 


78 


79 


79 


79 


79 


80 


80 


79 


79 


80 


80 


80 


80 


.013 


.012 


.012 


.01 


80 


80 


.013 


.013 


.013 


.012 


.012 


.012 


.012 


.011 



For SI units, 1 ft = 0.305 m. 



Table F.2, LP-Gases (Btu per hour). When the specific gravity 
of the utility gas is other than 0.60, select the multiplier from 
Table F.3 for the specific gravity of the utility gas served, and 
apply to the flow rate as determined from Table F.l. When the 
altitude is above 2000 ft (600 m), first select the equivalent 
orifice size at sea level using Table F.4, then determine the flow 
rate from Table F.l or Table F.2 as directed. Having deter- 
mined the flow rate (as adjusted for specific gravity and/or 
altitude where necessary), check the burner input at sea level 
with the manufacturer's rated input. 



F.1.2 To Select Correct Orifice Size for Rated Burner Input. 

The selection of a fixed orifice size for any rated burner input 
is affected by many variables, including orifice coefficient, and 
it is recommended that the appliance manufacturer be con- 
sulted for that purpose. When the correct orifice size cannot 



be readily determined, the orifice flow rates, as stated in the 
tables in this annex, can be used to select a fixed orifice size 
with a flow rate to approximately equal the required rated 
burner input. 

For gases of the specific gravity and pressure conditions 
stipulated at elevations under 2000 ft (600 m). Table F.l (in 
cubic feet per hour) or Table F.2 (in Btu per hour) can be 
used directly. 

Where the specific gravity of the gas is other than 0.60, 
select the multiplier from Table F.3 for the utility gas served 
and divide the rated burner input by the selected factor to 
determine equivalent input at a specific gravity of 0.60; then 
select orifice size as directed above. 

Where the appliance is located at an altitude of 2000 ft 
(600 m) or above, first use the manufacturer's rated input at sea 
level to select the orifice size as directed, then use Table F.4 to 
select the equivalent orifice size for use at the higher altitude. 



2002 Edition 



ANSIZ223.1-131 



ANNEX G 



54-131 



Annex G Sizing of Venting Systems Serving 

Appliances Equipped with Draft Hoods, Category I 

Appliances, and Appliances Listed for Use 

with Type B Vents 

This annex is not a part of the requirements of this code but is 
included for informational purposes only. 

G. 1 Examples Using Single Appliance Venting Tables. See Fig- 
ure G.l(a) through Figure G.l(n). 



Vent cap - 

TypeB 
double-wall 
gas vent 




U 









■ 


■ 


Tile-lined masonry — >- 
chimney 








Type B double-wall A 




, 1 


A 


y 


< L 


' 1 




'■. — ^— 






gas vent used as -^ 
connector 


t 

D 










A 


1 ' 




L=^ 1 










— > 


.— 






1 





^ 



Table 1 3.3 is used wlien sizing a Type B double-wall gas 
vent connector attached to a tile-lined masonry chimney. 

Notes: 

1 . y4 is the equivalent cross-sectional area of the tile liner. 

2. The appliance can be either Category I draft 
hood-equipped or fan-assisted type. 

FIGURE G. 1 (c) Vent System Serving a Single Appliance with a 
Masonry Chimney and a Type B Double-Wall Vent Connector. 



Table 13.1 is used when sizing Type B double-wall 
gas vent connected directly to the appliance. 

Note: The appliance can be either Category I draft 
hood-equipped or fan-assisted type. 

FIGURE G.l(a) Type B Double-Wall Vent System Serving a 
Single Appliance with a Type B Double-Wall Vent. 



Vent cap - 

TypeB 
double-wall - 
gas vent 



Single-wall — »- 
vent connector 











jk 


Tile-lined masonry — >- 
chimney 












H 




+ 












Single-wall — >- 
vent connector 


[ t 

D 








A 


1 


' 




^ 


\ 










! 








1 





Table 13.4 is used when sizing a single-wall vent 
connector attached to a tile-lined masonry chimney. 

Notes: 

1 . /4 is the equivalent cross-sectional area of the tile liner. 

2. The appliance can be either Category I draft 
hood-equipped or fan-assisted type. 

FIGURE G. 1 (d) Vent System Serving a Single AppUance Using 
a Masonry Chimney and a Single-Wall Metal Vent Connector. 



Table 13.2 is used when sizing a single-wall metal 

vent connector attached to a Type B double-wall gas vent. 

Note: The appliance can be either Category I draft 
hood-equipped or fan-assisted type. 

FIGURE G.l(b) Type B Double-Wall Vent System Serving a 
Single Appliance with a Single-Wall Metal Vent Connector. 



2002 Edition 



54-132 



NATIONAL FUEL GAS CODE 



ANSIZ223.1-132 



Vent cap 





Asbestos cement Type B or single-wall metal vent 
serving a single draft hood-equipped appliance. 
(See Table 13.5.) 

FIGURE G.l(e) Asbestos Cement Type B or Single-Wall 
Metal Vent System Serving a Single Draft Hood-Equipped 
Appliance. 



Vent cap 



Table 13.7 is used when sizing single-wall vent 
connectors attached to a Type B double-wall 
common vent. 

Note: Each appliance can be either Category I draft 
hood-equipped or fan-assisted type. 

FIGURE G.l(g) Vent System Serving Two or More Appli- 
ances with Type B Double-Wall Vent and Single-Wall Metal 
Vent Connectors. 



Type B double-wall 
common vent 




TypeB 
double-wall 
gas vent used 
as connectors 



Table 13.6 is used when sizing Type B double-wall 
gas vent connectors attached to a Type B 
double-wall common vent. 

Note: Each appliance can be either Category I draft 
hood-equipped or fan-assisted type. 

FIGURE G. 1 (f) Vent System Serving Two or More Appliances 
with Type B Double-Wall Vent and Type B Double-Wall Vent 
Connectors. 





, 
























■< — Tile-lined masonry 




TypeB 






chimney 




double-wall J 


A 


( — 




gas vent 








ij used as 
connecto 








rs 

/<? — I — 








\ 










D 




J^ 


N 


1 

Connector 
rise B 








-r- 


\\ 




' 


' 






D 


' 


1 


, 








1 


i 


i 





Table 13.8 is used when sizing Type B double-wall vent 
connectors attached to a tile-lined masonry chimney. 

Notes: 

1 . /4 is the equivalent cross-sectional area of the tile liner. 

2. Each appliance can be either Category I draft 
hood-equipped or fan-assisted type. 

FIGURE G. 1 (h) Masonry Chimney Serving Two or More 
Appliances with Type B Double-Wall Vent Connectors. 



2002 Edition 



ANSIZ223.1-133 



ANNEX G 



54-133 



, 


I 




















■< — Tile-lined masonry 
chimney 




— ' 


A 


f — 


t 


Single-wa 
connector 


1 vent 










f + 
D 




i 


\ 


Connector 


^ 










1 ^ rise F 
D 


1 
























^ 












1 









Table 13.9 is used when sizing single-wall metal vent 
connectors attached to a tile-lined masonry chimney. 

Notes: 

^. A\s the equivalent cross-sectional area of the tile liner. 
2. Each appliance can be either Category I draft 
hood-equipped or fan-assisted type. 

FIGURE G. 1 (i) Masonry Chimney Serving Two or More 
Appliances with Single-Wall Metal Vent Connectors. 



Manifold common r<- 
vent connector 



R2 _i_ 



Connectors 

< *■ 



§ 



■Lm- 



r -I )^ 



Example: Manifolded common vent connector Lm can 
be no greater than 18 times the common vent connector 
manifold inside diameter; that is, a 4 in. (100 mm) inside 
diameter common vent connector manifold should not 
exceed 72 in. (1800 mm) in length. (See 13.2.4.) 

Note: This is an illustration of a typical manifolded vent 
connector. Different appliance, vent connector, or 
common vent types are possible. (See Section 13.2.) 

FIGURE G. 1 (k) Use of Manifolded Common Vent Connector. 



± 



^ 



See 
13.2.5. 



■/-o-'H 



]-<— Vent cap 



(T^ 



X 



Asbestos cement Type B or single-wall metal pipe vent 
serving two or more draft hood-equipped appliances. 
(See Table 13. 10.) 

FIGURE G. 1 (j ) Asbestos Cement Type B or Single-WaU Metal 
Vent System Serving Two or More Draft Hood-Equipped Ap- 
pliances. 



See 
13.2.5. 



■*Lo-'-\ 



Common vent 



/r. 



]-*— Vent cap 



R 



Offset 



Connectors 



rl? 



^ 



«2 



Example: Offset common vent 

Note: This is an illustration of a typical offset vent. 
Different appliance, vent connector, or vent types are 
possible. (See Sections 13. 1. and 13.2.) 

HGURE G. 1 (1) Use of Offset Common Vent. 



2002 Edition 



54-134 



NATIONAL FUEL GAS CODE 



ANSIZ223.1-134 



Vent connector Tee 




Tee same size as 
segment above 

/ 



Common vent size 

based on all inputs * 
entering this segment 
and available total height 



Total input ■ 




I^J 



Rise 



Available total 
height H equals 
rise plus distance 
between tees 



Tee same 
j^ size as 
segment 
above 



Increase 
vent i 

connector T 
size if I 

necessary Other inputs 
from below 



Vent connector size 
depends on: 

• Input 

• Rise 

• Available total height H 

• Table 13.6 connectors 



Common vent size 
depends on: 

• Combined inputs 

• Available total height H 

• Table 13.6 common 
vent 



FIGURE G.l(m) Multistory Gas Vent Design Procedure for 
Each Segment of System. 



G. 1 . 1 Example 1 : Single Draft Hood-Equipped Appliance. An 

installer has a 120,000-Btu/hr input appliance with a 5 in. di- 
ameter draft hood oudet that needs to be vented into a 10 ft 
high Type B vent system. What size vent should be used assum- 
ing (1) a 5 ft lateral single-wall metal vent connector is used 
with two 90 degree elbows or (2) a 5 ft lateral single-wall metal 
vent connector is used with three 90 degree elbows in the vent 
system? See Figure G.1.1. 

Solution 

Table 13.2 should be used to solve this problem, because 
single-wall metal vent connectors are being used with a Type B 
vent, as follows: 

( 1 ) Read down the first column in Table 13.2 until the row asso- 
ciated with a 10 ft height and 5 ft lateral is found. Read across 
this row until a vent capacity greater than 120,000 Btu/hr is 
located in the shaded columns labeled NAT Max for draft 
hood-equipped appliances. In this case, a 5 in. diameter vent 
has a capacity of 122,000 Btu/hr and can be used for this 
application. 

(2) If three 90 degree elbows are used in the vent system, then 
the maximum vent capacity listed in the tables must be re- 
duced by 10 percent {see 13.1.3). This implies that the 5 in. 
diameter vent has an adjusted capacity of only 110,000 Btu/ 
hr. In this case, the vent system must be increased to 6 in. in 
diameter. See the following calculations: 

122,000x0.90 = 110,000 for 5 in. vent 
From Table 13.2, select 6 in. vent. 



Use individual vent for top-floor 
appliance if connector 
requirement for rise or total 
height cannot be met 



Listed cap 



Use vent 
connector 
table — ' 



Available total 
height for top- 
floor appliance 



Use available total 
height for top-floor 
appliance and 
combined input of 
all appliances on 
common vent 



Rise 



Top-floor- 
appliance 



Available total 
height for third- 
floor appliance 



Use vent - 

connector 

table 

Third-floor -^ 
appliance 



Rise 



IE 



Available total 
height for second- 
floor appliance 



Use vent 
connector 
table — ' 



Rise 



Use available total 
_height for second-floor 
"appliance and combined 

heat input of two 

appliances 

J First interconnection tee* 



^ 



Second-floor 
appliance ^■ 



^Third interconnection tee* 

Available total height 
for third-floor appliance 
and combined input of 
_three appliances 
(if top-floor appliance 
is not connected, 
measure total 
height to vent top) 

_Second interconnection 
tee* 



Design vent connector for 
first-floor appliance as an 
individual vent of this total 
height for input of first- 
floor appliance 



Tee with cap optional 



^ 



cs 



First-floor - 
appliance 



Each interconnection tee is same size as 
segment of common vent directly above 



FIGURE G.l(n) Principles of Design of Multistory Vents 
Using Vent Connector and Common Vent Design Tables. (See 
13.2.13 through 13.2.16.) 



186,000x0.90 = 167,000 

This figure is greater than the required 120,000. Therefore, 
use a 6 in. vent and connector where three elbows are used. 

G.1.2 Example 2: Single Fan-Assisted Appliance. An installer 
has an 80,000 Btu/hr input fan-assisted appliance that must be 
installed using 10 ft of lateral connector attached to a 30 ft 
high Type B vent. Two 90 degree elbows are needed for the 
installation. Can a single-wall metal vent connector be used for 
this application? See Figure G.1.2. 

Solution 

Table 13.2 refers to the use of single-wall metal vent con- 
nectors with Type B vent. In the first column find the row 
associated with a 30 ft height and a 10 ft lateral. Read across 
this row, looking at the FAN Min and FAN Max columns, to 
find that a 3 in. diameter single-wall metal vent connector is 



2002 Edition 



ANSIZ223.1-135 



ANNEX G 



54-135 



TypeB 
double-wall 
gas vent 



Elbow 




Draft hood- 
equipped appliance 
120,000-Btu/hr Input 



For SI units, 1 ft = 0.305 m. 

FIGURE G.1.1 Single Draft Hood-Equipped Appliance 
Example 1. 



Type B 
double-wall- 
gas vent 



10 ft lateral 



o 



Y 



y 



30 ft 



Vent connector 



Fan-assisted appliance 
80,000-Btu/hr Input 



For SI units, 1 ft = 0.305 m. 
FIGURE G.1,2 Single Fan-Assisted Appliance — Example 2. 

not recommended. Moving to the next larger size single wall 
connector (4 in.), we find that a 4 in. diameter single-wall 
metal connector has a recommended minimum vent capacity 
of 91,000 Btu/hr and a recommended maximum vent capac- 
ity of 144,000 Btu/hr. The 80,000 Btu/hr fan-assisted appli- 
ance is outside this range, so the conclusion is that a single- 
wall metal vent connector cannot be used to vent this 
appliance using 10 ft of lateral for the connector. 

However, if the 80,000 Btu/hr input appliance could be 
moved to within 5 ft of the vertical vent, then a 4 in. single-wall 
metal connector could be used to vent the appliance. Table 
13.2 shows the acceptable range of vent capacities for a 4 in. 
vent with 5 ft of lateral to be between 72,000 Btu/hr and 
157,000 Btu/hr. 

If the appliance cannot be moved closer to the vertical 
vent, then Type B vent could be used as the connector mate- 



rial. In this case, Table 13.1 shows that, for a 30 ft high vent 
with 10 ft of lateral, the acceptable range of vent capacities for 
a 4 in. diameter vent attached to a fan-assisted appliance is 
between 37,000 Btu/hr and 150,000 Btu/hr. 

G.1.3 Example 3: Interpolating Between Table Values. An in- 
staller has an 80,000 Btu/hr input appliance with a 4 in. diam- 
eter draft hood outlet that needs to be vented into a 12 ft high 
Type B vent. The vent connector has a 5 ft lateral length and is 
also Type B. Can this appliance be vented using a 4 in. diam- 
eter vent? 

Solution 

Table 13.1 is used in the case of an all Type B vent system. 
However, since there is no entry in Table 13.1 for a height of 
12 ft, interpolation must be used. Read down the 4 in. diam- 
eter NAT Max column to the row associated with 10 ft height 
and 5 ft lateral to find the capacity value of 77,000 Btu/hr. 
Read further down to the 15 ft height, 5 ft lateral row to find 
the capacity value of 87,000 Btu/hr. The difference between 
the 15 ft height capacity value and the 10 ft height capacity 
value is 10,000 Btu/hr. The capacity for a vent system wdth a 
12 ft height is equal to the capacity for a 10 ft height plus % of 
the difference between the 10 ft and 15 ft height values, or 
77,000 + % X 10,000 = 81,000 Btu/hr. Therefore, a 4 in. diam- 
eter vent can be used in the installation. 

G.2 Examples Using Common Venting Tables, 

G.2. 1 Example 4: Common Venting Two Draft Hood-Equipped 
Appliances. A 35,000-Btu/hr water heater is to be common 
vented with a 150,000 Btu/hr furnace, using a common vent 
with a total height of 30 ft. The connector rise is 2 ft for the 
water heater with a horizontal length of 4 ft. The connector 
rise for the furnace is 3 ft with a horizontal length of 8 ft. 
Assume single-wall metal connectors will be used with Type B 
vent. What size connectors and combined vent should be used 
in this installation? See Figure G.2.1. 
Solution 

Table 13.7 should be used to size single-wall metal vent 
connectors attached to Type B vertical vents. In the vent con- 
nector capacity portion of Table 13.7, find the row associated 
with a 30 ft vent height. For a 2 ft rise on the vent connector 
for the water heater, read the shaded columns for draft hood- 



j i Combined capacity 

>::::i!^ 35,000 + 150,000 = 

185,000 Btu/hr 

—Type B double- 
wall gas vent 




Draft hood- 
equipped 
water heater 
35,000 Btu/hr 
input 



Draft hood- 
equipped furnace 
150,000 Btu/hr 
input 



nCURE G.2. 1 Common Venting Two Draft Hood-Equipped 
Appliances — Example 4. 



2002 Edition 



54-136 



NATIONAL FUEL GAS CODE 



ANSIZ223.1-136 



equipped appliances to find that a 3 in. diameter vent connec- 
tor has a capacity of 37,000 Btu/hr. Therefore, a 3 in. single- 
wall metal vent connector can be used vfith the water heater. 
For a draft hood-equipped furnace with a 3 ft rise, read across 
the appropriate row to find that a 5 in. diameter vent connec- 
tor has a maximum capacity of 120,000 Btu/hr (which is too 
small for the furnace) and a 6 in. diameter vent connector has 
a maximum vent capacity of 172,000 Btu/hr. Therefore, a 6 in. 
diameter vent connector should be used with the 150,000 Btu 
per hr furnace. Since both vent connector horizontal lengths 
are less than the maximum lengths listed in 13.2.2, the table 
values can be used without adjustments. 

In the common vent capacity portion of Table 13.7, find 
the row associated with a 30 ft vent height and read over to the 
NAT + NAT portion of the 6 in. diameter column to find a 
maximum combined capacity of 257,000 Btu/hr. Since the 
two appliances total only 185,000 Btu/hr, a 6 in. common vent 
can be used. 

G.2.2 Example 5(a): Common Venting a Draft Hood- 
Equipped Water Heater with a Fan-Assisted Furnace into a 
Type B Vent. In this case, a 35,000-Btu/hr input draft hood- 
equipped water heater with a 4 in. diameter draft hood oudet, 
2 ft of connector rise, and 4 ft of horizontal length is to be com- 
mon vented with a 100,000 Btu/hr fan-assisted furnace with a 
4 in. diameter flue collar, 3 ft of connector rise, and 6 ft of hori- 
zontal length. The common vent consists of a 30 ft height of Type 
B vent. What are the recommended vent diameters for each con- 
nector and the common vent? The installer would like to use a 
single-wall metal vent connector. See Figure G.2.2. 



Combined capacity 
35,000 + 100,000 = 
135,000 Btu/hr 



M 



TypeB 

double-wall 

gas vent 30 ft 



3ft 



O 




Single-wall 
connectors 



Fan-assisted furnace 
100,000 Btu/hr input 



Water heater 
35,000 Btu/hr 
input 



For SI units, 1000 Btu/hr = 0.293 kW, 1 ft = 0.305 m. 

FIGURE G.2.2 Common Venting a Draft Hood-Equipped 
Water Heater with a Fan-Assisted Furnace into a Type B 
Double-Wall Common Vent — Example 5(a). 

Solution (See Table 13. 7.) 

Water Heater Vent Connector Diameter. Since the water heater vent 
connector horizontal length of 4 ft is less than the maximum 
value listed in Table 13.7, the venting table values can be used 
without adjustments. Using the Vent Connector Capacity portion 
of Table 13.7, read down the Total Vent Height (H) column to 
30 ft and read across the 2 ft Connector Rise (R) row to the first 
Btu/hr rating in the NAT Max column that is equal to or greater 
than the water heater input rating. The table shows that a 3 in. 
vent connector has a maximum input rating of 37,000 Btu/hr. 
Although this rating is greater than the water heater input rating. 



a 3 in. vent connector is prohibited by 13.2.19. A 4 in. vent con- 
nector has a maximum input rating of 67,000 Btu/hr and is 
equal to the draft hood oudet diameter. A 4 in. vent connector is 
selected. Since the water heater is equipped vnth a draft hood, 
there are no minimum input rating restrictions. 

Furnace Vent Connector Diameter. Using the Vent Connector 
Capacity portion of Table 13.7, read down the Total Vent 
Height (H) column to 30 ft and across the 3 ft Connector Rise 
(R) row. Since the furnace has a fan-assisted combustion sys- 
tem, find the first FAN Max column with a Btu/hr rating 
greater than the furnace input rating. The 4 in. vent connec- 
tor has a maximum input rating of 119,000 Btu/hr and a mini- 
mum input rating of 85,000 Btu/hr. 

The 100,000-Btu/hr furnace in this example falls within this 
range, so a 4 in. connector is adequate. Since the furnace vent 
connector horizontal length of 6 ft is less than the maximum 
value listed in 13.2.2, the venting table values can be used without 
adjustment. If the furnace had an input rating of 80,000 Btu/hr, 
then a Type B vent connector [see Table 13. 6] would be needed in 
order to meet the minimum capacity limit. 

Common Vent Diameter. The total input to the common vent 
is 135,000 Btu/hr. Using the Common Vent Capacity portion 
of Table 13.7, read down the Total Vent Height (H) column to 
30 ft and across this row to find the smallest vent diameter in 
the FAN + NAT column that has a Btu/hr rating equal to or 
greater than 135,000 Btu/hr. The 4 in. common vent has a 
capacity of 132,000 Btu/hr and the 5 in. common vent has a 
capacity of 202,000 Btu/hr. Therefore, the 5 in. common vent 
should be used in this example. 

Summary. In this example, the installer can use a 4 in. di- 
ameter, single-wall metal vent connector for the water heater 
and a 4 in. diameter, single-wall metal vent connector for the 
furnace. The common vent should be a 5 in. diameter Type B 
vent. 

G.2.3 Example 5(b): Common Venting into an Interior Ma- 
sonry Chimney. In this case, the water heater and fan-assisted 
furnace of Example 5(a) are to be common-vented into a clay- 
tile-lined masonry chimney with a 30 ft height. The chimney is 
not exposed to the outdoors below the roof line. The internal 
dimensions of the clay tile liner are nominally 8 in. x 12 in. As- 
suming the same vent connector heights, laterals, and materials 
found in Example 5 (a) , what are the recommended vent connec- 
tor diameters, and is this an acceptable installation? 

Solution 

Table 13.9 is used to size common venting installations in- 
volving single-wall connectors into masonry chimneys. 

Water Heater Vent Connector Diameter. Using Table 13.9, Vent 
Connector Capacity, read down the Total Vent Height (H) col- 
umn to 30 ft, and read across the 2 ft Connector Rise (R) row to 
the first Btu/hr rating in the NAT Max column that is equal to or 
greater than the water heater input rating. The table shows that a 
3 in. vent connector has a maximum input of only 31,000 Btu/hr, 
while a 4 in. vent connector has a maximum input of 57,000 
Btu/hr. A 4 in. vent connector must therefore be used. 

Furnace Vent Connector Diameter. Using the Vent Connector 
Capacity portion of Table 13.9, read down the Total Vent 
Height (H) column to 30 ft and across the 3 ft Connector Rise 
(R) row. Because the furnace has a fan-assisted combustion 
system, find the first FAN Max column with a Btu/hr rating 
greater than the furnace input rating. The 4 in. vent connec- 
tor has a maximum input rating of 127,000 Btu/hr and a mini- 
mum input rating of 95,000 Btu/hr. The 100,000 Btu/hr fur- 



2002 Edition 



ANSIZ223.1-137 



ANNEX G 



54-137 



nace in this example falls within this range, so a 4 in. 
connector is adequate. 

Masonry Chimney. From Table G.2.3, the Equivalent Area 
for a Nominal Liner size of 8 in. x 12 in. is 63.6 in.^. Using 
Table 13.9, Common Vent Capacity, read down the FAN + NAT 
column under the Minimum Internal Area of Chimney value 
of 63 to the row for 30 ft height to find a capacity' value of 
739,000 Btu/hr. The combined input rating of the furnace 
and water heater, 135,000 Btu/hr, is less than the table value, 
so this is an acceptable installation. 

Section 13.2.15 requires the common vent area to be no 
greater than seven times the smallest listed appliance catego- 
rized vent area, flue collar area, or draft hood outlet area. 
Both appliances in this installation have 4 in. diameter outlets. 
From Table G.2.3, the equivalent area for an inside diameter 
of 4 in. is 12.2 in.^. Seven times 12.2 equals 85.4, which is 
greater than 63.6, so this configuration is acceptable. 



Table G.2.3 Masonry Chimney Liner Dimensions with 
Circular Equivalents 







Inside 






Inside 


Diameter 




Nominal 


Dimensions 


or Equivalent 


Equivalent 


Liner Size 


of Liner 


Diameter 


Area 


(in.) 


(in.) 


(in.) 


(in.') 


4x8 


2V2 X 6V2 


4.0 


12.2 






5.0 


19.6 






6.0 


28.3 






7.0 


38.3 


8x8 


63/4 X 6% 


7.4 


42.7 






8.0 


50.3 


8x12 


6V2 X 101/2 


9.0 


63.6 






10.0 


78.5 


12x12 


93/4 X 93/4 


10.4 


83.3 






11.0 


95.0 


12 X 16 


91/2 X 131/2 


11.8 


107.5 






12.0 


113.0 






14.0 


153.9 


16x16 


13V4 X 131/4 


14.5 


162.9 






15.0 


176.7 


16x20 


13x17 


16.2 


206.1 






18.0 


254.4 


20x20 


161/2 X 163/4 


18.2 


260.2 






20.0 


314.1 


20x24 


I6I/2 X 201/2 


20.1 


314.2 






22.0 


380.1 


24x24 


201/4 X 201/4 


22.1 


380.1 






24.0 


452.3 


24x28 


201/4 X 241/4 


24.1 


456.2 


28x28 


241/4 X 241/4 


26.4 


543.3 






27.0 


572.5 


30x30 


251/2 X 251/2 


27.9 


607.0 






30.0 


706.8 


30x36 


251/2x311/2 


30.9 


749.9 






33.0 


855.3 


36 X 36 


311/2x311/2 


34.4 


929.4 






36.0 


1017.9 



For SI units, 1 in. = 25.4 mm, 1 in.^ = 645 mm^. 

Note: When liner sizes differ dimensionally from those shown in this 
table, equivalent diameters can be determined from published tables 
for square and rectangular ducts of equivalent carrying capacity or by 
other engineering methods. 



G.2.4 Example 5(c): Common Venting into an Exterior Ma- 
sonry Chimney. In this case, the water heater and fan-assisted 
furnace of Examples 5(a) and 5(b) are to be common-vented 
into an exterior masonry chimney. The chimney height, clay- 
tile-liner dimensions, and vent connector heights and laterals 
are the same as in Example 5(b). This system is being installed 
in Charlotte, North Carolina. Does this exterior masonry 
chimney need to be relined? If so, what corrugated metallic 
liner size is recommended? What vent connector diameters 
are recommended? See Table G.2.3 and Figure G.2.4. 

Solution 

According to 13.2.20, Type B vent connectors are required 
to be used with exterior masonry chimneys. Use Table 
13.13(a) and Table 13.13(b) to size FAN+NAT common vent- 
ing installations involving Type-B double wall connectors into 
exterior masonry chimneys. 

The local 99 percent winter design temperature needed to 
use Table 13.13(a) and Table 13.13(b) can be found in 
ASHRAE Handbook — Fundamentals. For Charlotte, North 
Carolina, this design temperature is 19°F. 

Chimney Liner Requirement. As in Example 5(b), use the 
63 in.^ Internal Area columns for this size clay tile liner. Read 
down the 63 in.^ column of Table 13.13(a) to the 30 ft height 
row to find that the Combined Appliance Maximum Input is 
747,000 Btu/hr. The combined input rating of the appliances 
in this installation, 135,000 Btu/hr, is less than the maximum 
value, so this criterion is satisfied. Table 13.13(b), at a 19°F 
Design Temperature, and at the same Vent Height and Inter- 
nal Area used earlier, shows that the minimum allowable input 
rating of a space-heating appliance is 470,000 Btu/hr. The 
furnace input rating of 100,000 Btu/hr is less than this mini- 
mum value. So this criterion is not satisfied, and an alternative 
venting design needs to be used, such as a Type B vent shown 
in Example 5(a) or a listed chimney liner system shown in the 
remainder of the example. 

According to 13.2.19, Table 13.6 or Table 13.7 are used for 
sizing corrugated metallic liners in masonry chimneys, with 
the maximum common vent capacities reduced by 20 percent. 
This example will be continued assuming Type B vent connec- 
tors. 

Water Heater Vent Connector Diameter. Using Table 13.6, Vent 
Connector Capacity, read down the Total Vent Height (H) col- 
umn to 30 ft, and read across the 2 ft Connector Rise (R) row 
to the first Btu/hour rating in the NAT Max column that is 
equal to or greater than the water heater input rating. The 
table shows that a 3 in. vent connector has a maximum capac- 
ity of 39,000 Btu/hr. Although this rating is greater than the 
water heater input rating, a 3 in. vent connector is prohibited 
by 13.2.19. A4 in. vent connector has a maximum input rating 
of 70,000 Btu/hr and is equal to the draft hood outiet diam- 
eter. A 4 in. vent connector is selected. 

Furnace Vent Connector Diameter. Using Table 13.6, Vent Con- 
nector Capacity, read down the Total Vent Height (H) column 
to 30 ft, and read across the 3 ft Connector Rise (R) row to the 
first Btu/hr rating in the FAN Max column that is equal to or 
greater than the furnace input rating. The 100,000 Btu/hr 
furnace in this example falls within this range, so a 4 in. con- 
nector is adequate. 

Chimney Liner Diameter. The total input to the common vent 
is 135,000 Btu/hr. Using the Common Vent Capacity Portion 
of Table 13.6, read down the Total Vent Height (H) column to 
30 ft and across this row to find the smallest vent diameter in 
the FAN+NAT column that has a Btu/hr rating greater than 



2002 Edition 



54-138 



NATIONAL FUEL GAS CODE 



ANSIZ223.1-138 




-10°F 
(-23° C) 



37° F 
(2°C) 



99% Winter Design Temperatures for the Contiguous United States 

This map is a necessarily generalized guide to temperatures in the contiguous United States. Temperatures shown for areas 
such as mountainous regions and large urban centers may not be accurate. The data used to develop this map are from the 
1993 ASHRAE Handbook— Fundamentals (Chapter 24, Table 1 : Climate Conditions for the United States). 

For 99% winter design temperatures in Alaska, consult the ASHRAE Handbook— Fundamentals. 

99% winter design temperatures for Hawaii are greater than 37°F. 

FIGURE G.2.4 Range of \\^ter Design Temperatures Used in Analyzing Exterior Masonry Chimneys in the United States. 



135,000 Btu/hr. The 4 in. common vent has a capacity of 
138,000 Btu/hr. Reducing the maximum capacity by 20 per- 
cent (see 13.2.19) results in a maximum capacity for a 4 in. 
corrugated Hner of 110,000 Btu/hr, less than the total input of 
135,000 Btu/hr. So a larger liner is needed. The 5 in. common 
vent capacity listed in Table 13.6 is 210,000 Btu/hr, and after 
reducing by 20 percent is 168,000 Btu/hr. Therefore, a 5 in. 
corrugated metal liner should be used in this example. 

Single Wall Connectors. Once it has been established that re- 
lining the chimney is necessary, Type B double wall vent con- 
nectors are not specifically required. This example could be 
redone using Table 13.7 for single-wall vent connectors. For 
this case, the vent connector and liner diameters would be the 
same as found for Type B double-wall connectors. 



Annex H Recommended Procedm-e for Safety 
Inspection of an Existing Appliance Installation 

This annex is not a part of the requirements of this code but is 
included for informational purposes only. 

H.l General. The following procedure is intended as a guide 
to aid in determining that an appliance is properly installed 
and is in a safe condition for continuing use. 



This procedure is predicated on central furnace and boiler 
installations, and it should be recognized that generalized 
procedures cannot anticipate all situations. Accordingly, in 
some cases, deviation from this procedure is necessary to de- 
termine safe operation of the equipment. 

( 1 ) This procedure should be performed prior to any attempt 
to modify the appliance or the installation. 

(2) If it is determined a condition that could result in unsafe 
operation exists, the appliance should be shut off and the 
owner advised of the unsafe condition. 

The following steps should be followed in making the 
safety inspection: 

(1) Conduct a test for gas leakage. (See Section 7.2.) 

(2) Visually inspect the venting system for proper size and 
horizontal pitch, and determine that there is no block- 
age, restriction, leakage, corrosion, or other deficiencies 
that could cause an unsafe condition. 

(3) Shut off all gas to the appliance, and shut off any other 
fuel gas burning appliance within the same room. Use 
the shutofif valve in the supply line to each appliance. 

(4) Inspect burners and crossovers for blockage and corrosion. 



2002 Edition 



ANSIZ223.1-139 



ANNEX I 



54-139 



(5) Applicable only to furnaces: Inspect the heat exchanger for 
cracks, openings, or excessive corrosion. 

(6) Applicable only to boilers: Inspect for evidence of water or 
combustion product leaks. 

(7) Insofar as is practical, close all building doors and win- 
dows and all doors between the space in which the appli- 
ance is located and other spaces of the building. Turn on 
clothes dryers. Turn on any exhaust fans, such as range 
hoods and bathroom exhausts, so they will operate at 
maximum speed. Do not operate a summer exhaust fan. 
Close fireplace dampers. If, after completing Steps 8 
through 13, it is believed suflFicient combustion air is not 
available, refer to Section 8.3 of this code for guidance. 

(8) Place the appliance being inspected in operation. Follow 
the lighting instructions. Adjust the thermostat so the 
appliance will operate continuously. 

(9) Determine that the pilot(s), where provided, is burning 
properly and that the main burner ignition is satisfactory 
by interrupting and re-establishing the electrical supply 
to the appliance in any convenient manner. If the appli- 
ance is equipped v«th a continuous pilot(s), test the pi- 
lot safety device (s) to determine whether it is operating 
properly by extinguishing the pilot(s) when the main 
burner(s) is off and determining, after 3 minutes, that 
the main burner gas does not flow upon a call for heat. If 
the appliance is not provided with a pilot(s), test for 
proper operation of the ignition system in accordance 
with the appliance manufacturer's lighting and operat- 
ing instructions. 

(10) Visually determine that the main burner gas is burning 
properly (i.e., no floating, lifting, or flashback). Adjust 
the primary air shutter (s) as required. If the appliance is 
equipped with high and low flame controlling or flame 
modulation, check for proper main burner operation at 
low flame. 

(11) Test for spillage at the draft hood relief opening after 5 
minutes of main burner operation. Use a flame of a 
match or candle or smoke. 

(12) Turn on all other fuel-gas-burning appliances within the 
same room so they will operate at their full inputs. Fol- 
low lighting instructions for each appliance. 

(13) Repeat Steps 10 and 11 on the appliance being in- 
spected. 

(14) Return doors, windows, exhaust fans, fireplace dampers, 
and any other fuel-gas-burning appliance to their previ- 
ous conditions of use. 

(15) Applicable only to furnaces: Check both the limit control 
and the fan control for proper operation. Limit control 
operation can be checked by blocking the circulating air 
inlet or temporarily disconnecting the electrical supply 
to the blower motor and determining that the limit con- 
trol acts to shut off the main burner gas. 

(16) Applicable only to boilers: Determine that the water pumps 
are in operating condition. Test low water cutoffs, auto- 
matic feed controls, pressure and temperature limit con- 
trols, and relief valves in accordance with the manufac- 
turer's recommendations to determine that they are in 
operating condition. 



Annex I Indoor Combustion Air Calculation 
Examples 

This annex is not a part of the requirements of this code but is 
included for informational purposes. 

1.1 New Installation. Determine if the indoor volume is suffi- 
cient to supply combustion air for the following new installa- 
tion example. 

Example Installation LA 100,000 Btu/hr fan assisted furnace 
and a 40,000 Btu/hr draft hood equipped water heater is be- 
ing installed in a basement of a new single family home. The 
basement measures 25 ft x 40 ft with an 8 ft ceiling. 

Solution 

(1) Determine the total required volume: Since the air infiltra- 
tion rate is unknovm, the standard method to determine 
combustion air is used to ceilculate the required volume. 

(a) The combined input for the appliances located in the 
basement is calculated as follows: 

100,000 Btu/hr + 40,000 Btu/hr = 140,000 Btu/hr 

(b) The Standard Method requires that the required vol- 
ume be determined based on 50 cubic feet per 1000 
Btu/hour. 

(c) Using Table A.8.3.2(a), the required volume for a 
140,000 Btu/hr combined input is 7,000 fr^ 

(2) Determine available volume: The available volume is the 
total basement volume: 

Available Volume: 25 ft x 40 ft x 8 ft ceiling - 8,000 ft^ 
Conclusion: The installation can use indoor air because 
the available volume of 8,000 ft^ exceeds the total re- 
quired volume of 7,000 ft^. No outdoor air openings are 
required. 

1.2 New Installation, Known Air InHltration Rate Method. De- 
termine if the indoor volume is sufficient to supply combus- 
tion air for the following replacement installation example. 

Example Installation 2: A 100,000 Btu/hr fan-assisted furnace 
and a 40,000 Btu/hr draft hood equipped water heater will be 
installed in a new single family house. It was determined (ei- 
ther by use of the ASHRAE calculation method or blower door 
test) that the house will have 0.65 air changes per hour. The 
furnace and water heater will be installed in a 20 ft x 35 ft 
basement with an 8 ft ceiling height. 

Solution 

(1) Determine the required volume: Because two types of ap- 
pliances are located in the space, a fan-assisted furnace 
and a draft hood equipped water heater, the required vol- 
ume must be determined for each appliance and then 
combined to determine the total required volume: 
(a) Fan-assisted furnace: For structures that the air infil- 
tration rate is known, method 8.3.2.2 permits the use 
of the equation in 8.3.2.2(2) to determine the re- 
quired volume for a fan-assisted appliance. Section 
8.3.2.2(3) limits the use of the equation to air change 
rates equal to or less than 0.60 ACH. While the house 
was determined to have a 0.65 ACH, 0.60 is used to 
calculate the required volume. Using the equation in 
8.3.2.2(2), the required volume for a 100,000 Btu/hr 
fan-assisted furnace is calculated as follows: 



2002 Edition 



54-140 



NATIONAL FUEL GAS CODE 



ANSIZ223.1-140 



15 ft Vl 00,000 Btu/hr 



(b) 



0.65 (^ 1,000 Btu/hr 

= 2,308ft' 

Because the calculated required volume of 2,308 ft^ 
falls below the lower required volume limit, the lower 
limit of 2,500 ft^ must be used as the minimum re- 
quired volume. 

Draft-hood equipped water heater: 
For structures that the air infiltration rate is known, 
method 8.3.2.2 permits the use the equation in 
8.3.2.2(1) to determine the required volume for a 
draft hood equipped appliance. Section 8.3.2.2(3) 
limits the use of the equation to air change rates 
equal to or less than 0.60 ACH. While the house was 
determined to have a 0.65 ACH, 0.60 is used to calcu- 
late the required volume. Using the equation in 
8.3.2.2(1), the required volume for the 40,000 
Btu/hr water heater is calculated as follows: 



21 ft Y 40,000 Btu/hr 



0.60 V 1,000 Btu/hr 

= 1,400 ft' 

Because the calculated required volume of 1,292 ft^ 
falls below the lower required volume limit, the lower 
limit of 1,400 ft^ must be used as the minimum re- 
quired volume. 

(c) Total required volume: 

Section 8.3.2 states that the total required volume to 
use indoor air is the sum of the required volumes for 
all appliances located in the space. 
Total Required = 2,500 ft^+ 1,400 ft^ = 3,900 ft^ 

(2) Determine available volume: The available volume is de- 
termined as follows: 

(20 ft X 35 ft) X 8 ft = 5,600 ft' 

Conclusion: The installation can use indoor air because 
the available volume of 5,600 ft^ exceeds the total re- 
quired volume of 3,900 ft^. No outdoor air openings are 
required. 

1.3 New Installation, Known Air Infilti"ation Rate Method. De- 
termine if the indoor volume is sufficient to supply combus- 
tion air for the following replacement installation example. 

Example Installation 3: A 100,000 Btu/hr fan-assisted furnace 
and a 40,000 Btu/hr draft hood equipped water heater v«ll be 
installed in a new single family house. It was determined (ei- 
ther by use of the ASHRAE calculation method or blower door 
test) that the house will have 0.30 air changes per hour. The 
furnace and water heater will be installed in an 20 ft x 35 ft 
basement with a 8 ft ceiling height. 

Solution 

(1) Determine the required volume: Because two types of ap- 
pliances are located in the space, a fan-assisted furnace 
and a draft hood equipped water heater, the required vol- 
ume must be determined for each appliance and then 
combined to determine the total required volume: 



(a) 



Fan-assisted furnace: For structures that the air infil- 
tration rate is known, method 8.3.2.2 permits the use 
of the equation in 8.3.2.2(2) to determine the re- 
quired volume for a fan-assisted appliance. Section 
8.3.2.3 limits the use of the equation to air change 
rates equal to or less than 0.60 ACH. Because 0.30 
ACH is less than 0.60 ACH, 0.30 can be used to calcu- 
late the required volume. Using the equation in 
8.3.2.2(2), the required volume for a 100,000 Btu/hr 
fan-assisted furnace is calculated as follows: 



15 ft 



3 /■ 



0.30 



100,000 Btu/hr 
1,000 Btu/hr 



(b) 



= 5, 000 ft' 

Draft-hood equipped water heater: For structures 
that the air infiltration rate is known, method 8.3.2.2 
permits the use of the equation in 8.3.2.2(1) to deter- 
mine the required volume for a draft hood equipped 
appliance. Section 8.3.2.2(3) limits the use of the 
equation to air change rates equal to or less than 0.60 
ACH. While the house was determined to have a 0.65 
ACH, 0.30 ACH is used to calculate the required vol- 
ume. Using the equation in 8.3.2.2(1), the required 
volume for the 40,000 Btu/hr water heater is calcu- 
lated as follows: 



21 ft' ("40,000 Btu/hr 



(2) 



0.30 1^ 1,000 Btu/hr 
= 2,800 ft' 

(c) Total required volume: Section 8.3.2 states that the 
total required volume to use indoor air is the sum of 
the required volumes for all appliances located in the 
space. 

Total Required = 5,000 ft='+ 2,800 ft^ = 7,800 ft^ 

Determine available volume: 

The available volume is determined as follows: 



(20 ft X 35 ft) X 8 ft = 5,600 ft' 

Conclusion: 

The installation cannot use indoor air alone, because the 
available volume of 5,600 ft^ is less than the total required 
volume of 7,800 ft^. Outdoor air openings can be sized in 
accordance with all air from the outdoors (see 8.3.3) or by 
use of the combination of indoor/ outdoor air method 
(see 8.3.4). 

Annex J Example of Combination of Indoor and 
Outdoor Combustion and Ventilation Opening Design 

This annex is not a part of the requirements of this code but is 
included for informational purposes only. 

J.l Example of Combustion Indoor and Outdoor Combus- 
tion Air Opening Design. Determine the required combina- 
tion of indoor and outdoor combustion air opening sizes for 
the following equipment installation example. 

Example /nstoWafion.' A fan-assisted furnace and a draft hood 
equipped water heater with the following inputs are located in 
a 15 ft X 30 ft basement with an 8 ft ceiling. No additional 
indoor spaces can be used to help meet the equipment com- 
bustion air needs. 



2002 Edition 



ANSIZ223.1-141 



ANNEX K 



54-141 



Fan-Assisted Furnace Input: 100,000 Btu/hr 

Draft Hood Equipped Water Heater Input: 40,000 Btu/hr 

Solution 

(1) Determine the total available room volume: 
Equipment room volume: 15 ft x 30 ft with an 8 ft ceiling 
= 3600 ft^ 

(2) Determine the total required volume: The standard 
method to determine combustion air will be used to cal- 
culate the required volume. 

The combined input for the appliances located in the 
basement is calculated as follows: 

100,000 Btu/hr -I- 40,000 Btu/hr = 140,000 Btu/hr 

The Standard Method requires that the required volume 
be determined based on 50 cubic feet per 1000 Btu/hour. 
Using Table A.8.3.2.1, the required volume for a 140,000 
Btu/hr water heater is 

7,000 ft^ 

Conclusion: Indoor volume is insixfficient to supply combus- 
tion air since the total of 3600 ft^ does not meet the required 
volume of 7000 ft^. Therefore, additional combustion air 
must be provided from the outdoors. 

(3) Determine ratio of the available volume to the required 
volume: 



3600 ft' 
7000 ft' 



= 0.51 



(4) 



(5) 



Determine the reduction factor to be used to reduce the 
full outdoor air opening size to the minimum required 
based on ratio of indoor spaces 

1.00 - 0.51 (from Step 3) = 0.49 
Determine the single outdoor combustion air opening 
size as if all combustion air is to come from outdoors. In 
this example, the combustion air opening directly com- 
municates wdth the outdoors. 



140,000 Btu/hr 
3,000 Btu/in.' 



= 47 in.' 



(6) Determine the minimum outdoor combustion air open- 
ing area: 

Outdoor opening area - 0.49 (from Step 4) x 47 in.^ = 
23 in.2 

Section 8.3.4(3) (c) requires the minimum dimension of the 
air opening should not be less than 3 in. 



Annex K Other Useful Definitions 

This annex is not a part of the requirements of this code but is 
included for informational purposes only. 

Kl Useful Terms. The following terms are not used in the 
code. They are used in appliance standards and by manufac- 
turers of products covered by the code. 

K.1.1 Ambient Temperature. The temperature of the sur- 
rounding medium; usually used to refer to the temperature of 
the air in which a structure is situated or a device operates. 

K 1 .2 Automatic Damper Regulator. A mechanically or electri- 
cally actuated device designed to maintain a constant draft on 
combustion equipment. 



K1.3 Burner, Induced-Draft. A burner that depends on draft 
induced by a fan that is an integral part of the appliance and is 
located downstream from the burner. 

K.1.4 Burner, Injection (Atmospheric). A burner in which the 
air at atmospheric pressure is injected into the burner by a jet 
of gas. 

K1.5 Burner, Power, Premixing. A power burner in which all 
or nearly all of the air for combustion is mixed with the gas as 
primary air. 

K.1.6 Conversion Burner, Gas, Firing Door Type. A conver- 
sion burner specifically for boiler or furnace firing door instal- 
lation. 

K.1.7 Conversion Burner, Gas, Inshot Type. A conversion 
burner normally for boiler or furnace ash pit installation and 
fired in a horizontal position. 

K.1.8 Conversion Burner, Gas, Upshot Type. A conversion 
burner normally for boiler or furnace ash pit installation and 
fired in a vertical position at approximately grate level. 

K.1.9 Decorative Appliance for Installation in a Vented Fire- 
place, Coal Basket. An open-flame-type appliance consisting 
of a metal basket that is filled with simulated coals and gives 
the appearance of a coal fire when in operation. 

K.1.10 Decorative Appliance for Installation in a Vented Fire- 
place, Fireplace Insert. Consists of an open-flame, radiant-type 
appliance mounted in a decorative metal panel to cover the 
fireplace or mantel opening and having provisions for venting 
into the fireplace chimney. 

Kl.ll Decorative Appliance for Installation in a Vented Fire- 
place, Gas Log. An open-flame-type appliance consisting of a 
metal frame or base supporting simulated logs. 

K.1.1 2 Decorative Appliance for Installation in a Vented Fire- 
place, Radiant Appliance. An open-front appliance designed 
primarily to convert the energy in fuel gas to radiant heat by 
means of refractory radiants or similar radiating materials. 

K.1.1 3 Fireplace, Factory-Built. A fireplace composed of listed 
factory-built components assembled in accordance with the 
terms of listing to form the completed fireplace. 

K.1.1 4 Fireplace, Masonry. A hearth and fire chamber of solid 
masonry units such as bricks, stones, listed masonry units, or 
reinforced concrete, provided with a suitable chimney. 

K.1.1 5 Floor Furnace, Fan-Type. A floor furnace equipped 
with a fan that provides the primary means for circulation of 
air. 

K. 1 . 1 6 Floor Furnace, Gravity-Type. A floor furnace depend- 
ing primarily on circulation of air by gravity. This classification 
also includes floor furnaces equipped vsdth booster-type fans 
that do not materially restrict free circulation of air by gravity 
flow when such fans are not in operation. 

K1.17 Furnace, Direct Vent Central. A system consisting of 
(1) a central furnace for indoor installation, (2) combustion 
air connections between the central furnace and the outdoor 
atmosphere, (3) flue-gas connections between the central fur- 
nace and the vent cap, and (4) a vent cap for installation out- 
doors, supplied by the manufacturer and constructed so that all 
air for combustion is obtained from the outdoor atmosphere and 
all flue gases are discharged to the outdoor atmosphere. 



2002 Edition 



54-142 



NATIONAL FUEL GAS CODE 



ANSIZ223.1-142 



K.1.18 Furnace, Downflow. A furnace designed with airflow 
discharge vertically downward at or near the bottom of the 
furnace. 

K1.19 Furnace, Forced Air, with Cooling Unit. A single- 
package unit, consisting of a gas-fired, forced-air furnace of 
the downflow, horizontal, or upflow type combined with an 
electrically or gas-operated summer air-conditioning system, 
contained in a common casing. 

K1.20 FiuTiace, Gravity. A furnace depending primarily on 
circulation of air by gravity. 

K.1.21 Furnace, Gravity, with Booster Fan. A furnace 
equipped with a booster fan that does not materially restrict 
free circulation of air by gravity flow when the fan is not in 
operation. 

K.1.22 Furnace, Gravity, with Integral Fan. A furnace 
equipped with a fan or blower as an integral part of its con- 
struction and operable on gravity systems only. The fan or 
blower is used only to overcome the internal furnace resis- 
tance to airflow. 

K.1.23 Furnace, Horizontal. Afurnace designed for low head- 
room installation with airflow across the heating element es- 
sentially in a horizontal path. 

K.1.24 Furnace, Upflow. A furnace designed with airflow dis- 
charge vertically upward at or near the top of the furnace. This 
classification includes "highboy" furnaces with the blower 
mounted below the heating element and "lowboy" furnaces 
with the blower mounted beside the heating element. 

K.1.25 Gas Main or Distribution Main. A pipe installed in a 
community to convey gas to individual services or other mains. 

K1.26 Household Cooking Gas AppUance, Floor-Supported 
Unit. A self-contained cooking appliance for installation di- 
rectly on the floor. It has a top section and an oven section. It 
may have additional sections. 

K1.27 Indirect Oven. An oven in which the flue gases do not 
flow through the oven compartment. 

K.1.28 Joint, Adhesive. A joint made in plastic piping by the 
use of an adhesive substance that forms a continuous bond be- 
tween the mating surfaces without dissolving either one of them. 

K.1.29 Joint, Solvent Cement. A joint made in thermoplastic 
piping by the use of a solvent or solvent cement that forms a 
continuous bond between the mating surfaces. 

K.1.30 Leak Detector. An instrument for determining con- 
centration of gas in air. 

K.1.31 Loads, Connected. Sum of the rated Btu input to indi- 
vidual gas utilization equipment connected to a piping system. 
May also be expressed in cubic feet per hour. 

K.1.32 Orifice Cap (Hood). A movable fitting having an ori- 
fice that permits adjustment of the flow of gas by the changing 
of its position with respect to a fixed needle or other device. 

K.1.33 Orifice Spud. A removable plug or cap containing an 
orifice that permits adjustment of the flow of gas either by 
substitution of a spud with a different sized orifice or by the 
motion of a needle with respect to it. 

K.1.34 Pressure Control. Manual or automatic maintenance 
of pressure, in all or part of a system, at a predetermined level, 
or within a selected range. 



K-1.35 Regulator, Gas AppUance, Adjustable. (1) Spring type, 
limited adjustment: a regulator in which the regulating force 
acting upon the diaphragm is derived principally from a 
spring, the loading of which is adjustable over a range of not 
more than ±15 percent of the outlet pressure at the midpoint 
of the adjustment range; (2) spring type, standard adjustment: 
a regulator in which the regulating force acting on the dia- 
phragm is derived principally from a spring, the loading of 
which is adjustable. 

K.1.36 Regulator, Gas AppUance, Multistage. A regulator for 
use with a single gas whose adjustment means can be posi- 
tioned manually or automatically to two or more predeter- 
mined outlet pressure settings. 

K-1.37 Regulator, Gas AppUance, Nonadjustable. (1) Spring 
type, nonadjustable: a regulator in which the regulating force 
acting on the diaphragm is derived principally from a spring, 
the loading of which is not field adjustable; (2) weight type: a 
regulator in which the regulating force acting upon the dia- 
phragm is derived from a weight or combination of weights. 

K. 1 .38 Room Heater, Unvented Circulator. A room heater de- 
signed to convert the energy in fuel gas to convected and radi- 
ant heat by direct mixing of air to be heated with the combus- 
tion products and excess air inside the jacket. 

K1.39 Room Heater, Vented. A vented, self-contained, free- 
standing, nonrecessed, fuel-gas-burning appliance for furnish- 
ing warm air to the space in which installed, directiy from the 
heater without duct connections. 

K1.40 Room Heater, Vented Circulator. A room heater de- 
signed to convert the energy in fuel gas to convected and radi- 
ant heat, by transfer of heat from flue gases to a heat ex- 
changer surface, without mixing of flue gases with circulating 
heated air. 

K.1.41 Room Heater, Vented Circulator, Fan Type. A vented 
circulator equipped with an integral circulating air fan, the 
operation of which is necessary for satisfactory appliance per- 
formance. 

K.1.42 Room Heater, Vented Overhead Heater. A room 
heater designed for suspension from or attachment to or ad- 
jacent to the ceiling of the room being heated and transfer- 
ring the energy of the fuel gas to the space being heated pri- 
marily by radiation downward from a hot surface, and in 
which there is no mixing of flue gases with the air of the space 
being heated. 

K-1.43 Room Heater, WaU Heater, Unvented Closed Front. 

An unvented circulator having a closed front, for insertion in 
or attachment to a wall or partition. 

K.1.44 Valve, Automatic Gas Shutoff. A valve used in conjunc- 
tion with an automatic gas shutoff device to shut off the gas 
supply to a fuel-gas-burning water heating system. 

K.1.45 Valve, Individual Main Burner. A valve that controls 
the gas supply to an individual main burner. 

K.1.46 Valve, Main Burner Control. A valve that controls the 
gas supply to the main burner manifold. 

K.1.47 Valve, Manual Main Gas Control. A manually operated 
valve in the gas line for the purpose of completely turning on 
or shutting off the gas supply to the appliance, except to a 
pilot or pilots that are provided with independent shutoff. 



2002 Edition 



ANSIZ223.1-143 



ANNEX L 



54-143 



K.1.48 Vented Wall Furnace, Fan-Type. A wall furnace that is 
equipped with a fan. 

K1.49 Vented Wall Furnace, Gravity-Type. A wall furnace that 
depends on circulation of air by gravity. 

K.1.50 Venting System, Mechanical Draft, Induced. A portion 
of a venting system using a fan or other mechanical means to 
cause the removal of flue or vent gases under nonpositive 
static vent pressure. 

K.1.51 Venting System, Mechanical Draft, Power. 5^^ Venting 
System, Mechanical Draft, Forced. 

K.1.52 Water Heater, Automatic Circulating Tank. A water 
heater that furnishes hot water to be stored in a separate ves- 
sel. Storage tank temperatures are controlled by means of a 
thermostat installed on the water heater. Circulation can be 
either gravity or forced. 

K.1.53 Water Heater, Automatic Instantaneous. A water 
heater that has a rated input of at least 4000 Btu/hr/gal (5 
kW/L) of self-stored water. Automatic control is obtained by 
water-actuated control, thermostatic control, or a combina- 
tion of water-actuated control and thermostatic control. This 
classification includes faucet-type water heaters designed to 
deliver water through a single faucet integral with or directly 
adjacent to the appliance. 

K1.54 Water Heater, CoU Circulation. A water heater whose 
heat transfer surface is composed primarily of water tubes less 
than IV2 in. (38 mm) in internal diameter and that requires 
circulation. 

K.1.55 Water Heater, Commercial Storage. A water heater that 
heats and stores water at a thermostatically controlled tempera- 
ture for delivery on demand. Input rating: 75,000 Btu/hr 
(21,980 W) or more. 

K.1.56 Water Heater, Countertop Domestic Storage. (1) Con- 
cealed type: a vented automatic storage heater that is designed 
for flush installation beneath a countertop 36 in. (910 mm) 
high, wherein the entire heater is concealed; (2) flush type: a 
vented automatic storage water heater that has flat sides, top, 
front, and back and is designed primarily for flush installation 
in conjunction with or adjacent to a counter 36 in. (910 mm) 
high, wherein the front and top of the heater casing are ex- 
posed; and (3) recessed type: a vented automatic storage water 
heater that has flat sides, top, front, and back and is designed 
for flush installation beneath a counter 36 in. (910 mm) high, 
wherein the front of the heater casing is exposed. 

K.1.57 Water Heater, Domestic Storage. A water heater that 
heats and stores water at a thermostatically controlled tem- 
perature for delivery on demand. Input rating may not exceed 
75,000 Btu/hr (21,980 W). 

K.1.58 Water Heater, Nonautomatic Circulating Tank. A wa- 
ter heater that furnishes hot water to be stored in a separate 
vessel. Storage tank temperatures are controlled by means of a 
thermostat installed in the storage vessel. 



Annex L Informational References 

L.l Referenced PubUcations. The following documents or 
portions thereof are referenced within this code for informa- 
tional purposes only and are thus not part of the requirements 
of this document unless also listed in Chapter 14. 



L.1.1 NFPA Publications. National Fire Protection Associa- 
tion, 1 Batterymarch Park, RO. Box 9101, Quincy, MA 02269- 
9101, (617)770-3000, www.nfpa.org. 

NFPA 30, Flammable and Combustible Liquids Code, 2000 edition. 

NFPA 59, Utility LP-Gas Plant Code, 2001 edition. 

NFPA 59A, Standard for the Production, Storage and Handling 
of Liquefied Natural Gas (LNG), 2001 edition. 

NFPA 61, Standard for the Prevention of Fires and Dust Explo- 
sions in Agricultural and Food Processing Facilities, 2002 edition. 

NFPA 68, Guide for Venting of Deflagrations, 2002 edition. 

NFPA 70, National Electrical Code®, 2002 edition. 

NFPA 86, Standard for Ovens and Furnaces, 1999 edition. 

NFPA88B, Standard for Repair Garages, 1997 edition. 

NFPA90A, Standard for the Installation ofAir-Conditioningand 
Ventilating Systems, 2002 edition. 

NFPA 90B, Standard for the Installation of Warm Air Heating 
and Air-Conditioning Systems, 2002 edition. 

NFPA 96, Standard for Ventilation Control and Fire Protection of 
Commercial Cooking Operations, 2001 edition. 

NFPA 211, Standard for Chimneys, Fireplaces, Vents, and Solid 
Fuel-Burning Appliances, 2000 edition. 

NFPA 501 A, Standard for Fire Safety Criteria for Manufactured 
Home Installations, Sites, and Communities, 2000 edition. 

L.l. 2 Other Publications. 

L.l. 2.1 API Publication. American Petroleum Institute, 1220 
L Street, NW, Washington, DC 20005. 

API 1104, Standard for Welding Pipelines and Related Facilities, 
1999. 

L. 1.2.2 ASHRAE Publications. American Society of Heating, 
Refrigerating and Air-Conditioning Engineers, Inc., 1791 Tul- 
He Circle, N.E., Atianta, GA 30329-2305, (404)636-8400, ww- 
w.ashrae.org. 

ASHRAE Handbook — Fundamentals, 1997. 

ASHRAE Handbook — HVAC Systems and Equipment, 1999. 

L.l. 2. 3 ASME PubUcation. American Society of Mechanical 
Engineers, Three Park Avenue, New York, NY 10016-5990, 
(800)843-2763, www.asme.org. 

ASME Boiler and Pressure Vessel Code, Section IX and Section 
IV, 1998. 

L.l. 2.4 ASTM Publications. American Society for Testing and 
Materials, 100 Barr Harbor Drive, West Conshohocken, PA 
19428-2959, (610)833-9585, www.astm.org. 

ANSI/ASTM D 2385, Method of Test for Hydrogen Sulfide and 
Mercaptan Sulfur in Natural Gas (Cadmium Sulfate — lodometric 
Titration Method), 1981. 

ANSI/ASTM D 2420, Method of Test for Hydrogen Sulfide in 
Liquefied Petroleum (LP) Gases (Lead Acetate Method), 1991 (Reaf- 
firmed 1996). 

L.l. 2.5 AWS Publications. American Welding Society, 550 
N. W. Lejeune Road, Miami, FL 33126, (800)443-9353, 
www.aws.org. 

AWS B2.1, Standard for Welding Procedure and Performance 
Qualification, 1998. 

AWS B2.2, Standard for Brazing Procedure and Performance 
Qualification, 1991. 



2002 Edition 



54-144 



NATIONAL FUEL GAS CODE 



ANSIZ223.1-144 



L.1.2.6 CSA-America Publications. CSA-America, Inc., 8501 
East Pleasant Valley Road, Cleveland, OH 44131, (216)524- 
4990, www.csa-america.org. 

AGA/CGA NGV 1, Compressed Natural Gas Vehicle (NGV) Fu- 
eling Connection Devices, 1999. 

AGA/CGA NGV 3.1, Fuel System Components for Natural Gas 
Powered Vehicles, 1999. 

ANSI/IAS LC 2A, Agricultural Heaters, 1998. 

ANSI Z21.1, Household Cooking Gas Appliances, 2000. 

ANSI Z21.5.1/CSA7.1, Gas Clothes Dryers — Volume I— Type 

1 Clothes Dryers, 1999. 

ANSI Z21.5.2/CSA7.2, Gas Clothes Dryers — Volume 11— Type 

2 Clothes Dryers, 2001. 

ANSI Z21.10.1/CSA 4.1, Gas Water Heaters — Volume I — 
Storage, Water Heaters with Input Ratings of 75, 000 Btu per Hour or 
Less, 2001. 

ANSI Z21.10.3/CSA 4.3, Gas Water Heaters — Volume III — 
Storage, Water with Input Ratings above 73, 000 Btu per Hour, Cir- 
culating and Instantaneous, 2001. 

ANSI Z2 1.1 1.1, Gas-Fired Room Heaters — Volume I — Vented 
Room Heaters, 1991. (Included in Z21.86/CSA2.32, 2000.) 

ANSI Z21.11.2, Gas-Fired Room Heaters — Volume II — Un- 
vented Room Heaters, 2000. 

ANSI Z21.12, Draft Hoods, 1990 (Reaffirmed 2000). 

ANSI Z21.13/CSA 4.9, Gas-Fired Low-Pressure Steam and Hot 
Water Boilers, 2000 (Reaffirmed 1998). 

ANSI Z21.15/CGA9.1, Manually Operated Gas Valves for Ap- 
pliances, Appliance Connector Valves, and Hose End Valves, 1997. 

ANSI Z21.17/CSA 2.7, Domestic Gas Conversion Burners, 
1998. 

ANSI Z21.18/CSA 6.3, Gas Appliance Pressure Regulators, 
2000. 

ANSI Z21.19/CSA1.4, Refrigerators Using Gas Fuel, 2002 (Re- 
affirmed 1999). 

ANSI Z21.20, Automatic Gas Ignition Systems and Components, 
2000. 

ANSI Z21.21/CGA 6.5, Automatic Valves for Gas Appliances, 
2000. 

ANSI Z21.22/CSA4.4, Relief Valves and Automatic Gas Shutoff 
Deuices for Hot Water Supply Systems, 1999 (Reaffirmed 1998). 

ANSI Z21.23, Gas Appliance Thermostats, 2000 (Reaffirmed 
1998). 

ANSI Z21.24/CSA6.10, Metal Connectors for Gas Appliances, 
2001. 

ANSI Z21.35/CGA6.8, Pilot Gas Filters, 1995. 

ANSI Z21.40.1/CGA2.91-M96, Gas-Fired Absorption Summer 
Air Conditioning Appliances, 1996. 

ANSI Z21.40.2/CGA 2.92, Gas-Fired Work Activated Air- 
Conditioning and Heat Pump Appliances (Internal Combustion), 
1996. 

ANSI Z21.40.4/CGA 2.94, Performance Testing and Rating of 
Gas Fired, Air-Conditioning and Heat Pump Appliances, 1996. 

ANSI Z21.41/CSA 6.9, Quick-Disconnect Devices for Use With 
Gas Fuel, 1998. 

ANSI Z21.42, Gas-Fired Illuminating Appliances, 1993 (Reaf- 
firmed 1998). 

ANSI Z21.47/CSA2.3, Gas-Fired Central Furnaces, 2001. 

ANSI Z21.50/CSA2.22, Vented Gas Fireplaces, 2000. 

ANSI Z21.54/CSA 8.4, Gas Hose Connectors for Portable Out- 
door Gas-Fired Appliances, 1996. 

ANSI Z21.56/CSA4.7, Gas-Fired Pool Heaters, 2001. 



ANSI Z21.57, Recreational Vehicle Cooking Gas Appliances, 
2001 (Reaffirmed 1998). 

ANSI Z21.58/CGA 1.6, Outdoor Cooking Gas Appliances, 1995 
(Reaffirmed 2001). 

ANSI Z21.60/CGA2.26, Decorative Gas Appliances for Instal- 
lation in Solid-Fuel Burning Fireplaces, 1996. 

ANSI Z21.61, Gas-Bred Toilets, 1983 (Reaffirmed 1996). 

ANSI Z21.66/CGA 6.14, Automatic Vent Damper Devices for 
Use with Gas-Fired Appliances, 1996. 

ANSI Z21.69/CSA 6.16, Connectors for Movable Gas Appli- 
ances, 1997 (Reaffirmed 2001). 

ANSI Z21.71, Automatic Intermittent Pilot Ignition Systems for 
Field Installations, 1993 (Reaffirmed 1998). 

ANSI Z21.77/CGA 6.23, Manually-Operated Piezcy-Electric 
Spark Gas Ignition Systems and Components, 1995. 

ANSI Z21.78/CGA6.20, Combination Gas Controls for Gas Ap- 
pliances, 2000. 

ANSI Z21.83, Fuel Cell Power Plants, 1998. 

ANSI Z21.84, Manually Lighted, Natural Gas, Decorative Gas 
Appliances for Installation in Solid-Fuel Burning Appliances, 1999. 

ANSI Z21.86/CSA2.32, Vented Gas-Fired Space Heating Equip- 
ment, 2000. 

ANSI Z21.87/CSA4.6, Automatic Gas Shutoff Devices for Hot 
Water Supply Systems, 1999. 

ANSI Z21.88/CSA2.33, Vented Gas-Fireplace Heaters, 2000. 

ANSI Z21.91, Ventless Firebox Enclosures for Gas-Fired Unvented 
Decorative Room Heaters, 2001 . 

ANSI Z83.3, Gas Utilization Equipment in Large Boilers, 1971 
(Reaffirmed 1995). 

ANSI Z83.4/CSA 3.7, Direct Gas-Fired Make-Up Air Heaters, 
1999 (Reaffirmed 1998). 

ANSI Z83.6, Gas-Fired Infrared Heaters, 1990 (Reaffirmed 
1998). 

ANSI Z83.8/CGA2.6, Gas Fired Duct Furnaces and Unit Heat- 
ers, 1996. 

ANSI Z83.il/CGA 1.8, Food Service Equipment, 1996. 

IAS U.S. 7, Requirements for Gas Convenience Outlets and Op- 
tional Enclosures, 1990. 

IAS U.S. 9, Requirements for Gas-Fired, Desiccant Type Dehu- 
midifiers and Central Air Conditioners, 1990. 

IAS U.S. 42, Requirement for Gas Fired Commercial Dishwashers, 
1992. 

IAS NGV2, Basic Requirements for Compressed Natural Gas Ve- 
hicle (NGV) Containers, 1998. 

L,1.2.7 MSS Publications. Manufacturers Standardization So- 
ciety of the Valve and Fittings Industry, 5203 Leesburg Pike, 
Suite 502, Falls Church, VA 22041. 

MSS SP-6, Standard Finishes for Contact Faces of Pipe Flanges 
and Connecting-End Flanges of Valves and Fittings, 1999. 

ANSI/MSS SP-58, Pipe Hangers and Supports — Materials, 
Design and Manufacture, 1993. 

L.1.2.8 NACE Publication. National Association of Corrosion 
Engineers, 1440 South Creek Drive, Houston, TX 77084. 

NACE RP 0169, Control of External Corrosion on Underground 
or Submerged Metallic Piping Systems, 1996. 

L.1.2.9 UL Publications. Underwriters Laboratories Inc., 333 
Pfingsten Road, Northbrook, IL 60062. 

UL 103, Chimneys, Factory-Built, Residential Type and Building 
Heating Appliances, 1995. 



2002 Edition 



ANSIZ223.1-145 



ANNEX L 



54-145 



ANSI/UL441, Gas Vents, 1996. 
ANSI/UL 641, Low-Temperature Venting Systems, 1995. 
UL1738, Venting Systems for Gas Burning Appliances, Categories 
II, III and IV, 1993. 

UL 1777, Chimney Liners, 1996. 

L. 1.2. 10 U.S. Government Publication. U.S. Government 
Printing Office, Washington, DC 20402. 

Manufactured Home Construction and Safety Standard, Title 24, 
Code of Federal Regulations, Part 3280. 

L.2 Informational References. (Reserved) 



L.3 References for Extracts. The following documents are 
listed here to provide reference information, including titie and 
edition, for extracts given throughout this code as indicated by a 
reference in brackets [ ] following a section or paragraph. These 
documents are not a part of the requirements of this document 
unless also listed in Chapter 14 for other reasons. 

NFPA 101®, Life Safety Code®, 2000 edition. 
NFPA 211, Standard for Chimneys, Fireplaces, Vents, and Solid 
Fuel-Burning Appliances, 2000 edition. 

NFPA 501, Standard on Manufactured Housing, 2000 edition. 



2002 Edition 



54-146 



NATIONAL FUEL GAS CODE 



ANSI Z223.1-146 



Index 

© 2002 National Fire Protection Association. All Rights Reserved. 

The copyright in this index is separate and distinct from the copyright in the document that it indexes. The licensing provisions set forth for the 
document are not applicable to this index. This index may not be reproduced in whole or in part by any means without the express written 
permission of NFR\. 



Abovegroimd piping 6.2 

Access doors and panels 

Duct furnaces 9.10.3 

Floor furnaces 9.11.8 

Wall heaters 9.27.1.5 

Accessible 

Definition 3.3.1 

Gas utilization equipment 8.2.1 

On roofs 8.4.3 

Readily (definition) 3.3.2 

Valves 6.9.2.1 

Adoption of code A. 1 .5 

Agency, qualiHed 1.4 

Definition 3.3.175 

Air 

Circulating 9.7.3, 9.10.5, 9.11.3, 9.26.3, 9.27.3 

Definition 3.3.4 

Ducts 10.3.6 

Combustion see Combustion air 

Dilution see Dilution air 

Excess (definition) 3.3.80 

Make-up see Make-up air 

Primary see Primary air 

Process 8.1.7 

Use under pressure 8.1.5 

Air conditioners, gas-fired 9.2, A.9.2.6 

Definition 3.3.5 

Air conditioning (definition) 3.3.6 

Aircraft hangars 

Duct furnaces in 9.10.7 

Heaters in 8.1.12, 9.18.4, 9.26.5 

Air ducts see Ducts 

Air shutter (definition) 3.3.7 

Altitiide, high 11.1.2, 13.1.5, 13.2.10, F. 1.1, Table R5 

Ambient temperature (definition) K.1.1 

Anchors, pipe 6.2.6 

Anodeless risers 5.6.4.1 

Definition 3.3.8 

Appliance categorized vent diameter /area (definition) 3.3.11 

Appliances 

Approval 8.1.1, A.8.1.1 

Automatically controlled (definition) 3.3.10 

Categorized Vent Diameter 

Area see Vent Sizes 

Combination units 

Chimneys 10.5.5.3, 10.5.5.4 

Venting Table 10.4.1, A.10.5.5.3 

Converted 8.1.2, 8.1.3 

Counter (gas) see Food service equipment, gas 

Decorative see Decorative appliances 

Definition 3.3.9 

Direct vent see Direct vent appliances 

Fan-assisted combustion 

Definition 3.3.12 

Venting system Annex G 

Household cooking see Household cooking appliances 

Illuminating 9.16, Table 9.16.2.2 

Installation of Chap. 8 

Low-heat 10.5.2.1, Table 10.7.4.4, 10.10.2.5, 10.10.14.2(3) 

Medium-heat 10.5.2.2, Table 10.7.4.4, 10.10.14.3 



Nonresidential, low-heat 

Definition 3.3.13 

Nonresidential, medium-heat 

Definition 3.3.14 

Outdoor cooking see Outdoor cooking gas appliances 

Placing in operation 7.3.4 

Pressure regulators 5.8.5.2, 8.1.18, 8.1.19 

Purging 7.3.4 

Vented see Vented appliances 

AppUcability of code 1.1.1 

Approved (definition) 3.3.15, A.3.3.15 

Atmospheric pressure (definition) 3.3.16 

Attics, apphances in 10.10.2.4(1) 

Authority having jurisdiction (definition) 3.3.17, A.3.3.17 

Automatically operated vent dampers 10.14 

Automatic damper regulator (definition) K.1.2 

Automatic firechecks 6.12.1 (3), 6.12.6, A.6.12.4, A.6. 12.6(1) 

Definidon 3.3.18 

Automatic gas shutoff devices 9.28.5 

Definition 3.3.19 

Automatic ignition 11.4; see also Ignition 

Definition 3.3.20 

Automatic valves (definition) 3.3.214 

-B- 

Backfillmg 6.1.2.3 

Backfire preventers see Safety blowouts 

Back pressure 

Definidon 3.3.21 

Protecdon 5.10 

Baffle (definition) 3.3.23 

Barometric draft regulators 8.3.1.4, 10.12.4 to 10.12.6 

Definidon 3.3.24 

Bathroom, installation in 9.1.2, A.9.1.2 

Bedroom, installation in 9.1.2, A.9.1.2 

Bends 

Pipe 6.5, A.6.5.3 

Vent connectors 10.10.6 

Bleeds 

Diaphragm-type valves 8.1.20 

Industrial air heaters 9.8.6, 9.9.6 

Blowers, mixing see Mixing blowers 

Boilers 

Central headng 9.3, A.9.3.6, A.9.3.7.3 

Assembly and installation 9.3.3 

Clearance Table 9.2.3(a) , Table 9.2.3(b) , 9.3.2 

Cooling units used with 9.3.9 

Low water cutoff 9.3.5, 11.5 

Steam safety and pressure relief valves 9.3.6, A.9.3.6 

Temperature- or pressure-limiting devices 9.3.4 

Hot water heating (definidon) 3.3.25 

Hot water supply (definidon) 3.3.26 

Low-pressure (definidon) 3.3.27 

Steam heating (definition) 3.3.28 

Bonding, electrical 6.13 

Branch lines 6.2.3, 6.4.1, 6.8 

Branch length pipe sizing method ... 12.1.2, A.12. 1.2, C.3.2, C.7.3 
Definition 3.3.29 

Breeching 5^e Vent connectors 

Broilers 

Definidon 3.3.31 



2002 Edition 



ANSIZ223.1-147 



INDEX 



54-147 



Household cooking gas appliance 

Definition 3.3.128 

Protection above 9.19.3 

Unit 

Commercial 9.19.4 

Definition 3.3.209 

Domestic, protection above 9.19.3 

Open-top 9.19 

Btu A.5.4.2 

Definition 3.3.32 

Buildings 
Piping in 

Building structure for 6.2.2 

Concealed 6.3 

Connection of gas utilization equipment to 8.5, A.8.5.6 

Prohibited locations 6.2.5 

Piping under 6.1.6 

Structural members 8.1.8 

Built-in household cooking apphances 9.15.2 

Burners see also Conversion burners, gas 

Combination gas and oil burners 

Chimneys for 10.5.5.4 

Venting system Table 10.4.1 

Definition 3.3.33 

Forced draft see subhead: Power 

Gas conversion see Conversion burners, gas 

Induced-draft (definition) K.1.3 

Injection (atmospheric) (definition) K.1.4 

Injection (Bunsen) type (definition) 3.3.35 

Input adjustment 11.1, Table 11.1.1, A.ll. 1.1 

Power 

Definition 3.3.36 

Fan-assisted (definition) 3.3.37 

Premixing (definition) K.1.5 

Primary air adjustment 11.2, A. 11. 2 

In residential garages 8.1.10.1 

Bypass piping 5.8.6 

Bypass valves 

Gas line pressure regulators 5.8.6 

Pool heaters 9.21.4 

-C- 

Capping, of oudets 6.7.2 

Carpeting, installation of gas utilization equipment on 8.2.3 

Casters, for floor-mounted food service equipment 9.12.6 

Central furnaces see Furnaces 

Central premix system 6.12, A.6.12 

Definition 3.3.38 

Chases, vertical, piping in 6.4 

Chimneys 10.5, A.10.5.1.3 

Checking draft 11.6, A.11.6 

Cleanouts 10.5.4.3, 10.5.7 

Definition 3.3.39 

Factory-built 10.5.1.1, 10.5.2.4, 10.5.6, 10.5.8.1, 10.10.2.6(4) 

Definition 3.3.40 

Masonry 10.5.1.3, 10.5.8.1, 10.6.1(6), 13.1.7, 13.2.19, 

A.10.5.1.3, G.2.3 see also Exterior masonry chimneys 

Definition 3.3.41 

Metal 10.5.1.2, 10.5.8.1 

Definition 3.3.42 

Obstructions 10.15, 13.1.1 

Vent connectors 10.10.2.5, 10.10.2.6, 10.10.3.3, 10.10.11 

Venting system 13.1.7, 13.1.9, 13.2.19, 13.2.20, 

Table 13.8, Table 13.9, Tables 13.11 to 13.13, A. 13. 1.7, 
G.2.3 

Circuits, electrical 6.14, 8.6.3 

Circulating air see Ait, Circulating 

Clearances 8.2.2 

Air-conditioning equipment, indoor installation 9.2.3 

Boilers, central heating Table 9.2.3(a), Table 9.2.3(b), 9.3.2 

Clothes dryers 9.4.1 



Draft hoods 10.12.7 

Food service equipment 

Counter appliances 9.13.1 to 9.13.3 

Floor-mounted 9.12.1, 9.12.2 

Outdoor cooking appliances 9.20.2 

Furnaces 

Central 9.3.2 

Duct 9.10.1 

Floor 9.11.7 

Gas-fired toilets 9.25.1 

Heaters 

Industrial air 9.8.4, 9.9.4 

Infrared 9.18.2 

Pool 9.21 .2 

Room 9.23.3 

Unit 9.26.2 

Water 9.28.2 

Illuminating appliances 9.16.1, 9.16.2, Table 9.16.2.2 

Refrigerators, gas 9.22.1 

Single-wall metal pipe for vents 10.7.4.4 

Vent connectors 10.10.5 

Clothes dryers 

Definition 3.3.43 

Installation 9.4 

Multiple family or public use 9.4.5.6, 9.4.6 

Type 1 9.4.1 (1 ) , 9.4.2, 9.4.4, 10.2.2(4) 

Definition 3.3.44 

Type 2 9.4.1 (2) , 9.4.2, 9.4.5 

Definition 3.3.45 

Venting 8.3.1.5, 9.4.2 to 9.4.5, 10.2.2(4) 

Coal basket see Decorative appliances, 

to install in vented fireplaces 
Combustible material 

Clearances to see Clearances 

Definition 3.3.46 

Food service equipment mounted on/adjacent to 9.12.3, 

9.12.5,9.13.4,9.14 

Roofs, metal pipe passing through 10.7.4.5 

Combustion (definition) 3.3.47 

Combustion air 8.1.2(1), 8.3,A.8.3 

Combination indoor and outdoor 8.3.4, J. 1 

Ducts 8.3.8 

Engineered installations 8.3.5 

Floor furnaces 9.11.3 

Gas fireplaces, vented 9.7.3 

Indoor 8.3.2, Fig. A.8.3.2.1, Tables A.8.3.2(a) to (c) 

Calculation examples Annex I 

Infrared heaters 9.18.3 

Mechanical supply 8.3.6 

Outdoor ...8.3.3, Fig.A.8.3.3.1(l),Fig.A.8.3.3.1(2),Fig.A.8.3.3.2 

Unit heaters 9.26.3 

Wall heaters 9.27.3 

Combustion chamber (deHnition) 3.3.48 

Combustion products (deHnition) 3.3.49 

Common vent 10.6.4, 10.10.3.5, 10.10.3.6, 

13.2.4 to 13.2.9, Annex G 

Definition 3.3.50 

Common vent manifold 8.1.19(6), 8.1.20(5), 13.2.4 

Definition 3.3.51 

Compressed natural gas (CNG) vehicular fuel systems 9.29 

Concealed gas piping 

In buildings 6.3 

Definition 3.3.52 

Condensate (condensation) 

Definition 3.3.53 

Drain 10.9 

Connections 

Air conditioners 9.2.2 

Chimney 10.10.11 

Electrical 6.15, 8.6.1 

Gas 5.13.2 

Branch 6.4.1, 6.8 



2002 Edition 



54-148 



NATIONAL FUEL GAS CODE 



ANSIZ223.1-148 



Concealed piping 6.3.2 

Plastic and metallic piping 6.L7.1, 6.L7.2 

Gas equipment 8.5, A.8.5.6 

Portable and mobile industrial gas equipment 8.5.3 

Connectors 

Gas hose, to gas utilization equipment 8.5.2 

Vent see Vent connectors 

Construction 

Chase 6.4.2 

Checklist B.2 

Coordination B.l 

Overpressure protection devices 5.9.3 

Single-wall metal pipe 10.7.1 

Consumption (definition) 3.3.54 

Control piping 

Definition 3.3.55 

Overpressure protection devices 5.9.4 

Controls 

Definition 3.3.56 

Draft 10.12, 10.15 

Duct furnaces 9.10.4 

As obstructions 10.15 

Protective devices 11 .5 

Safety shutoff devices see Safety shutofF devices 

Convenience oudets, gas 6.7.1.6, 8.5.6 

Definition 3.3.57 

Conversion burners, gas 9.5 

Definition 3.3.58 

Firing door type (definition) K.1.6 

Inshot type (definition) K.1.7 

Upshot type (definition) K.1.8 

Cooking appliances see Food service equipment, gas; Household 

cooking appliances 

Cooling units see also Refrigeration systems 

Boilers, used with 9.3.9 

Furnaces, used with 9.3.8 

Corrosion, protection against 5.6.2.4, 5.6.2.5, 5.6.3.3, 

5.6.6, 6.1.3, 6.3.5.1, 6.3.5.2, 10.5.1.3, A.6.1.3, A.10.5.1.3 

Counter appliances, gas see Food service equipment, gas 

Cubic feet (cu ft.) of gas 5.4.2, A.5.4.2 

Definidon 3.3.60 



-D- 

Dampers 

Automatically operated vent 10.14 

Chimney, free opening area of Table 9.6.2.3 

Gravity 9.8.7.2,9.9.7.2 

Manually operated 10.13 

Obstructions and 13.1.1 

Outside 9.8.5, 9.9.5 

Decorative appliances, to install in vented fireplaces 9.6, 

Table 9.6.2.3, Table 10.4.1, A.9.6.1 

Coal basket (definition) K.1.9 

Definition 3.3.61 

Fireplace insert (definition) K.1.10 

Gas log (definidon) K.1.11 

Radiant appliance (definition) K.1.12 

Deep fat fryer see Food service equipment, gas 

Defects, detection of 5.6.5, 7.1.5 

Definitions Chap. 3, Annex K 

Design 

Checklist B.2 

Coordination B.l 

Design certification (definition) 3.3.63 

Design pressure 

Allowable pressure drop 5.4.1, 5.4.4, A.5. 4.1, C.6(4) 

Definition 3.3.64 

Maximum 5.5.1, A.5.5.1 (1) 

Detectors, leak see Leak detectors 

DUution air 8.3.1.1 to 8.3.1.3, 8.3.5, 8.3.7.1 

Definition 3.3.65 



Direct gas-fired industrial air heaters 

Air supply 9.8.5, 9.9.5, A.9.9.5 

Definition 3.3.66 

Nonrecirculating 9.8 

Definition 3.3.130 

Prohibited installations 9.9.2 

Recirculating 9.9 

Definition 3.3.131 

Direct gas-fired makeup air heaters 

Definition 3.3.67 

Venting 10.2.2(9) 

Direct vent appliances 

Definition 3.3.68 

Venting of 10.2.5, Table 10.4.1, 10.6.2(1) (c), 

10.8.1 Ex. 1, 10.8.3 

Direct vent central fxmiaces (definition) K.1.17 

Distribution mains or gas mains (definition) K. 1 .25 

Diversity factor (definition) 3.3.69 

Draft(s) 8.7.2 

Checking 11.6, A.11.6 

Definition 3.3.70 

Mechanical 10.3.4, 10.6.2(1) (e), 10.8.1, 10.8.2, 10.10.4.2 

Definition 3.3.71 

Natural (definition) 3.3.72 

Requirements 10.3.2 

Draft controls 10.12, 10.15 

Draft hoods 8.3.1.4, 9.10.4, 10.12, 11.6, A.10.12.4, A.11.6 

Chimneys 10.5.1.3 Ex., 10.5.2.3, 10.5.3.1 

Definition 3.3.73 

Vent connectors Table 10.7.4.4 

Vents and venting systems Table 10.4.1, 10.6.3.1, 

10.7.5(1), 10.10.2.2, 10.10.2.3, 10.10.3, 13.1.2, 13.1.4, 
13.1.9(3), 13.2.11, 13.2.12, 13.2.17, 13.2.20(2), 13.2.21, 
Table 13.10, Annex G 

Draft regulators 10.15; see also Barometric draft regulators 

Definition 3.3.74 

Drain, condensation 10.9 

Drip liquids 4.3.2.1 

Drips 6.2.3, 6.6 

Definition 3.3.75 

Dry gas 6.2.3, 6.2.4 

Definition 3.3.76 

Duct furnaces 9.10 

In commercial garages and aircraft hangars 9.10.7 

Definition 3.3.77 

Use with refrigeration systems 9.10.6 

Ducts 

Air 8.3.8, 9.2.3(6), 9.3.7, 9.25, 10.3.6, A.9.3.7 

Exhaust 9.4.4, 9.4.5 

Unit heaters 9.26.4 

-E- 

Effective ground-fault current path (definition) 3.3.78 

ebows 6.5.4, 13.1.3, 13.2.6, 13.2.7 

Electrical systems 6.13 to 6.15 

Air conditioning equipment 9.2.7 

Gas utilization equipment 8.6 

Ignition and control devices 8.6.2 

Enforcement of code 1.5, A.l .5 

Engines, stationary gas 9.24 

Equipment ^ee Appliances; Gas utilization equipment 

Equipment shutoff valves see Valves 

Equivalency to code 1.4 

Excess air (defiiution) 3.3.80 

Exhaust systems, mechanical See Mechanical exhaust systems 

Explosion heads (soft heads or rupture discs) 6.12.6(4), A.6.12. 4 

Definition 3.3.81 

Exterior masonry chimneys Tables 13.11 to 13.13, G.2.4; see also 

Chimneys 
Definition 3.3.82 



2002 Edition 



ANSI Z223. 1-149 



INDEX 



54-149 



-F- 

Fan-assisted combustion system appliances 13.2.21 

Definition 3.3.83 

Venting system 10.10.3.1, Annex G 

EAN+EAN 13.2.1(3), Tables 13.6 to 13.9 

Definition 3.3.86 

FAN Max 13.1.6, Tables 13.1 to 13.4, 

13.2.3(1), 13.2.18, Tables 13.6 to 13.9 
Definition 3.3.84 

FANMin 13.1.1(2), 13.1.6, Tables 13.1 to 13.4, 

13.2.1(3), 13.2.3(2), 13.2.18, Tables 13.6 to 13.9 
Definition 3.3.85 

FAN+NAT 13.2.1(2), 13.2.1(3), 13.2.20(3), 

13.2.20(4), Tables 13.6 to 13.9, Table 13.13(a), Table 
13.13(b) 
Definition 3.3.87 

Firechecks see Automatic firechecks 

Fireplace insert see Decorative appliances, to install in vented 

fireplaces 

Fireplaces see also Decorative appliances, to install in vented 

fireplaces 

Definition 3.3.88 

Factory-built (definition) K.1.13 

Gas see Gas fireplaces 

Make-up air 8.3.1.5 

Masonry (definition) K.1.14 

Outlets, capping 6.7.2.2 

Vent connectors 10.10.13 

Fireplace screens 9.6.3 

Fittings 

Concealed piping 6.3.2 

Corrosion, protection against 5.6.6, 6.1.3, 6.3.5.2 

Gas pipe turns 6.5, A.6.5.3 

Gas utilization equipment connections 8.5.1(1), 8.5.1(2) 

Metallic 5.6.8, A.5.6.8.1 

Overpressure relief device 5.9.8 

Plastic 5.6.4, 5.6.9 

Used 5.6.1.2 

Workmanship and defects 5.6.5 

Flame arresters 6.12.2(2), A.6.12.4, A.6.12.6(l) 

Definition 3.3.89 

Flammable liquids, handling of 4.3.2 

Flammable vapors, gas appliances in area of 8.1 .9 

Flange gaskets 5.6.11 

Flanges 5.6.10 

Floor furnaces 9.11 

Definition 3.3.90 

Fan-type (definition) K.1.15 

First floor installation 9.11.12 

Gravity-type (defmidon ) K.1.16 

Upper floor installation 9.11.11 

Floor-mounted equipment 

Food service 9.12, A.9.12.8 

Household cooking appliances 9.15.1 

Unit heaters 9.26.2.2 

Floors, piping in 6.3.5, 10.10.14 

Flowmeters 6.12.2(1) 

Flues 

Appliance (definition) 3.3.91 

Chimney (definition) 3.3.92 

Flue coUars 10.5.2.3, 10.10.3.6, 13.1.2, 

13.1.4, 13.2.11, 13.2.12, 13.2.17, 13.2.21 

Defmidon 3.3.93 

Multiple, on single appliance 10.10.3.2 

Flue gases 

Definiuon 3.3.94 

Vendng of 8.1.14 

Food service equipment, gas; see also Broilers 

Combustible material adjacent to cooking top 9.12.5 

Connections 8.5.1(6) 

Counter appliances 9.13 



Definiuon 3.3.95 

Deep fat fryers (definition) 3.3.96 

Floor-mounted 9.12, A.9.12.8 

Gas-fired kettle (definition) 3.3.97 

Oven, baking and roasdng (defmidon) 3.3.98 

Range 10.2.2(1) 

Definiuon 3.3.99 

Steam cooker (defmidon) 3.3.100 

Steam generator (definition) 3.3.101 

Venting 10.2.2(1) to (3), 10.2.2(8) 

Forced-air furnaces see Furnaces 

Foundations, piping through 6.1.5 

Freezing, protection against 6.1.4, 6.2.3, A.6.1.4 

Fuel cell power plants 9.31 

Furnace plenums 9.2.3(5) , 9.2.3(6) , 9.2.5, 9.3.2.6, 9.3.7, 

10.3.6, A.9.3.7.3 

Definidon 3.3. 105 

Furnaces 

Central Table 9.2.3(a) , Table 9.2.3 (b) , 9.3, A.9.3.6, A.9.3.7.3 

Definidon 3.3.102 

Direct vent central (definiuon) K.1.17 

Downflow (definition) K. 1 . 1 8 

Duct see Duct furnaces 

Enclosed (definition) 3.3.103 

Floor see Floor furnaces 

Forced-air 

With cooling unit 9.3.8(1) 

Definidon K. 1 . 1 9 

Definition 3.3.104 

Gravity 

With booster fan K.1.21 

Definition K.1.20 

With integral fan K.1.22 

Horizontal (definidon) K.1.23 

Refrigeration coils and 9.3.8 

Upflow (definidon) K.1.24 

Wall see Wall furnaces 



Garages 

Commercial 

Duct furnaces in 9.10.7 

Gas utilization equipment in 8.1.11 

Heaters in : 8.1.11.2, 9.18.4, 9.26.5 

Repair 

Definition 3.3.106 

Gas utilization equipment in 8.1.11.2 

Residential 

Definition 3.3.107 

Gas utilization equipment in 8.1.10 

Gas-air mixtures 

Flammable 6.12, A.6.12 

Outside the flammable range 6.11 

Gases 

Definition 3.3.117 

Dry see Dry gas 

Flow of, through fixed orifices Annex F 

Flue 

Definition 3.3.194 

Venting of 8.1.14 

LP-Gas systems see LP-Gas systems 

Maximum demand 5.4.1, 5.4.2, A.5.4.1, A.5.4.2 

Purged, discharge of 7.3.3 

Used in gas utiUzation equipment 8.1.3 

Utility (definition) 3.3.212 

Vent (definition) 3.3.229 

Gas fireplaces see also Decorative appliances, to install in vented 

fireplaces 

Direct vent (definition) 3.3.108 

Vented 9.7, A.9.7.1 

Definition 3.3.109 



2002 Edition 



54-150 



NATIONAL FUEL GAS CODE 



ANSIZ223.1-150 



Gaskets, flange 5.6.1 1 

Gas log see Decorative appliances, to install in vented fireplaces 

Gas mains (deflnition) K. 1 .25 

Gas-mixing machines 6.11, 6.12.1(1), 6.12.3 

Definition 3.3.110 

Installation 6.12.5, A.6.12.5.L A.6.12.5.4 

Gas reUefs 9.8.6, 9.9.6 

Gas supplier regulations 1.1.2 

Gas utilization equipment 

Accessibility 8.2.1 

Added or converted 8.1.2, 8.1.3 

Air for combustion and ventilation 8.3, A.8.3 

Approval 8.1.1, A.8.1.1 

Bleed lines for diaphragm-type valves 8.1.20 

Carpeting, installation on 8.2.3 

Clearance to combustible materials 8.2.2 

Combination 8.1 .21 

Connections to building piping 8.5, A.8.5.6 

Convenience oudets 8.5.6 

Coordination of design, construction, 

and maintenance Annex B 

Definition 3.3.1 11 

Electrical systems 8.6 

Extra devices or attachments 8.1.15 

Installation Chap. 8 

Instructions 

Installation 8.1.22 

Operating 11.7 

Louvers and grilles 8.3.7 

Mechanical exhausting and A.8.3 

Mobile, connections 8.5.3 

Operation procedures Chap. 1 1 

Outdoor, protection of 8.1.23 

Physical protection 8.1.13, 8.5.1(7) 

Piping 

Capacity of 8.1.16 

Strain on 8.1.17 

Placing in operation 7.3.4 

Portable, connections 8.5.3 

Pressure regulators 8.1.18, 8.1.19 

Protection from fumes and gases 8.1.6, A.8.1.6 

On roofs 8.4 

Type of gas(es) 8.1.3 

Venting 8.1.14, Chap. 10 

In well-ventilated spaces 10.2.4 

Gas vents 10.6 

Checking draft 11 .6, A. 1 1 .6 

Definition 3.3.112 

Integral, equipment with 10.2.6, Table 10.4.1, 10.6.2(1) (d) 

Multistory design Fig. G.l(m), Fig. G.l(n) 

Serving equipment on more than one floor 10.6.4 

Size of A.10.6.3.1 

Spaces surrounding 10.5.8 

Special type 10.4.3, 10.5.8 

Definition 3.3.113 

Type B Table 10.4.1, 10.5.1.3 Ex., 10.5.3.1, 

10.6.1(4), 10.6.2(2), 10.6.4.2, Table 10.7.4.4, 
10.10.2.4(l)(a), 10.10.14.1 Ex., 10.10.14.2(1), 
13.1.9, 13.2.20 

Definition 3.3.114 

TypeB-W Table 10.4.1, 10.6.1(2), 10.6.2(3) 

Definition 3.3.115 

Type L Table 10.4.1, 10.6.1 (2), 10.6.1 (4), 

Table 10.7.4.4, 10.10.2.4(1) (a), 10.10.14.1 Ex. 

Definition 3.3.116 

Wall heaters 9.27.1.3, 9.27.1.4 

Governor, zero 6.12.4 

Definition 3.3.118 

Gravity see Specific gravity 

Gravity furnaces see Furnaces 

Grilles 

Protecting openings 8.3.7 



Wall heaters 9.27.1.5 

Grounding, electrical 6.13 



-H- 

Hangars i^f Aircraft hangars 

Hangers, pipe 6.2.6 

Health care occupancy (deHnition) 3.3.153 

Heaters see also Direct gas-fired industrial air heaters; Direct 

gas-fired makeup air heaters; Infrared heaters; Pool 
heaters; Room heaters; Unit heaters; Water heaters 

In aircraft hangars 8.1.12, 9.18.4, 9.26.5 

In commercial garages 8.1.11.2, 9.18.4, 9.26.5 

Heating value (total) (definition) 3.3.121 

Heat pumps, gas-fired 9.2, A.9.2.6 

Definition 3.3.120 

Heat reclaimers 10.15 

High altitude see Altitude, high 

Hoods 

Draft see Draft hoods 

Duct furnaces 9.10.4 

Ventilating see Ventilating hoods 

Hoop stress (definition) 3.3.122 

Hot plates 

Commercial see Food service equipment, gas 

.Definition see Food service equipment, gas counter 

Domestic 9.14 

Definition 3.3.124 

Venting 10.2.2(3) 

Hot taps (definition) 3.3.125 

Household cooking appliances 9.15; see also Outdoor cooking gas 

appliances 

Built-in units 9.15.2 

Floor-mounted 9.15.1 

Household cooking gas appliances 
Broilers 

Definition 3.3.128 

Built-in units 

Definition 3.3.127 

Definition 3.3.126 

Floor-supported unit (definition) K.1.2.6 

Hybrid pressure system 

Definition 3.3.129 

Pipe sizing 12.1.3, C.3.3, C.7.2 



Identification 

Gas pressure regulators 5.8.6 

Meters, gas 5.7.5 

Ignition 

Accidental, prevention of 4.3 . 

Automatic 5ee Automatic ignition 

Electrical 8.6.2 

Sources 4.3.1 

Definition 3.3.196 

Dluminating appliances 9.16, Table 9.16.2.2 

Incinerators 

Commercial-industrial 9.17 

Draft regulators, barometric 10.12.4 

Vent connectors 10.10.2.6 

Venting 10.3.4.2 Ex., Table 10.4.1, 10.5.3.2 

Indirect ovens (definition) K.1.27 

Induced-draft burners (definition) K,l .3 

Industrial air heaters see Direct gas-fired industrial air heaters 

Infrared heaters 9.18 

Definition 3.3.132 

Injection (atmospheric) burners (definition) K.1 .4 

Injection (Bunsen) type burners (definition) 3.3.35 

Inspections 

Chimneys 10.5.4 

Draft 11.6, A.l 1.6 



2002 Edition 



ANSIZ223.1-151 



INDEX 



54-151 



Existing installation Annex H 

Gas piping 7.1, A.7.1.1 

Ignition, automatic II .4 

Protective devices 11.5 

Safety shutofF devices 11.3 

Vent connectors 10.10.12 

Installations 

Chimneys 10.5.1, 10.5.2, A.10.5.1.3 

Draft hoods and draft controls 10.12.2, 10.12.3 

Electrical 8.6 

Equipment Chap. 8 

Gas piping Chap. 6 

Overpressure protection devices 5.9.3 

Single-wall metal pipe for vents 10.7.4 

Specific equipment Chap. 9 

Instructions 

Gas utilization equipment installation 8.1.22 

Manufacturers 1.1.2 

Operating 11.7 

Insulating millboard (deHnition) 3.3.133 

Interruption of service 4.2 

Interruption of work 4.2.2 



Joining methods 5.6, A.5.6 

Joint compounds, thread see Thread joint compounds 

Joints 

Adhesive (definition) K.1.28 

Concealed piping 6.3.2 

Corrosion, protection against 6.1.3, A.6.1.3 

Definition 3.3.134 

Flared 5.6.8.3 

Metallic 5.6.8, A.5.6.8.1 

Plastic 5.6.9, 6.5.2(2) 

Solvent cement (definition) K.1.29 

Tubing 5.6.8.2 

Vent connectors 10.10.7 



-K- 

Kettie, gas-fired see Food service equipment, gas 



Labeled (definition) 3.3.136 

Laimdry stoves, domestic 9.14 

Definition 3.3.137 

Venting 10.2.2(3) 

Leakage 

Emergency procedure for Annex E 

Pressure test 7.1.5 

System and equipment test 7.2, A.7.2.3 

Leak check 

Definition 3.3.138 

Suggested method Annex D 

Leak detectors 7.1.5 

Definition K.1.30 

Limit controls 11.5; see also Temperature limit controls/devices 

Definition 3.3.139 

Listed (definition) 3.3.140, A.3.3.140 

Loads, connected (definition) K. 1 .31 

Longest length pipe sizing method 12.1.1, A.12.1. 1, C.3.1, C.7.1 

Louvers 

Heaters 9.8.5, 9.8.7.2 

Industrial air heaters 9.9.5, 9.9.7.2 

Protecting openings 8.3.7 

LP-Gas systems 5.5.2, 5.6.7.4, 8.1.4 

Fixed orifices, flow of gas through Table F.2, Table F.3 

Leakage check D.3(2) 

Pipe sizing tables C.2.3 

Plastic pipe, use of 5.6.9(4) 



-M- 

Main bimiers (definition) 3.3.141 

Maintenance B.l, B.3 

Make-up air 8.3.1 .5, 9.4.3; see also Direct gas-fired makeup air 

heaters 

Manifolds, gas (definition) 3.3.142 

Manual reset valves see Valves, Manual reset 

Manufactured homes 

AppHances for 9.30 

Definition 3.3.143 

Manufacturer's instructions 1.1.2 

Marking 

Gas vents 10.6.6 

Single-wall metallic pipe 10.7.7 

Masonry chimneys see Chimneys 

Maximum working pressure 

Definition 3.3.144 

Overpressure relief device and 5.9.5 

Mechanical exhaust systems 8.3.1.5, 8.3.6, 

10.3.5, 10.6.2(1) (f),A.10.3.5 

Clothes dryers 9.4.2, 9.4.4, 9.4.5 

Definition 3.3.145 

Metallic pipe 5.6.2, A.5.6.2.3; see also Tubing 

Connection to plastic piping 6.1.7.2 

Corrosion, protection against 5.6.2.4, 5.6.2.5, 

5.6.3.3, 5.6.6, 6.3.5.1, 6.3.5.2 

Gas utilization equipment connections 8.5.1(1), 8.5.1(2) 

Joints and fittings 5.6.8 

Low pressure gas pipe sizing tables C.2.2 

Single-wall, for venting 10.7, Table 10.7.4.4, 

13.2.22, Table 13.10, A.10.7.5(l) 
Sizing .... Tables 12.1 to 12.6, Tables 12.22 to 12.24, Table C.5(a) 

Threads 5.6.2.4, 5.6.7 

Turns 6.5.1 

Meter (definition) 3.3.146 

Meters, gas 5.7, A.5.7 

Mitered bends 6.5.3, A.6.5.3 

Mixing blowers 6.12.3, 6.12.4, 6.12.5.3, A.6.12.4 

Definition 3.3.147 

Multistory installations 13.2.13 to 13.2.15 

-N- 

NA 13.1.1 (2) , 13.2.1 (3) 

Definition 3.3.148 

NAT Max 13.1.1(1), 13.1.6, Tables 13.1 to 13.4, 

13.2.1(1), 13.2.3(1), 13.2.18, Tables 13.6 to 13.9 

Definition 3.3.149 

NAT+NAT 13.2.1(2), 13.2.20(3), 13.2.20(4), 

Tables 13.6 to 13.9, Table 13.12(a), Table I3.12.(b) 

Definition 3.3.150 

Noncombustible material 9.2.4 

Definition 3.3.151 

Thimbles 10.7.4.5 

Nondisplaceable valve member (definition) 3.3.152 

Notification of interrupted service 4.2. 1 

-o- 

Occupancy 

Health care (definition) 3.3.153 

Residential board and care (definition) 3.3.154 

Offset, vent 13.2.5 

Definition 3.3.155 

Opening see also Relief openings 

Chimneys 10.5.5.2 

Combination indoor and outdoor combustion air 8.3.4, J. 1 

Indoor combustion air 8.3.2.3 

Outdoor combustion air 8.3.3, Fig. A.8.3.3.1(l), 

Fig. A.8.3.3.I(2), Fig. A.8.3.3.2 
Pipe, size of 5.9.8 

Operation of equipment, procedures Chap. 11 



2002 Edition 



54-152 



NATIONAL FUEL GAS CODE 



ANSIZ223.1-152 



Orifice cap (hood) 

Definition K.L32 

Orifices 

Definition 3.3.156 

Fixed, flow of gas through Annex F 

Orifice spud (definition) K. L33 

Outdoor cooking gas appliances 9.20 

Definition 3.3.157 

Outlets 

Convenience see Convenience outlets, gas 

Piping 6.7 

Outside, installation of piping 6.2; see also Underground piping 

Ovens 

Baking and roasting see Food service equipment, gas 

Indirect (definition) K.1 .27 

Overpressure protection devices 5.9 

Piping in vertical chases 6.4.1 

Setting 5.9.5 

Unauthorized operation 5.9.6 

Oxygen 

As test medium 7.1.2 

Use under pressure 8.1 .5 

-P- 

Parking structures 

Basement or underground (definition) 3.3.160 

Definition 3.3.159 

Enclosed (definition) 3.3.161 

Gas utilizadon equipment in 8.1.11.1 

Partitions 

Piping in 6.3.3 

Tubing in 6.3.4 

Pilot (definition) 3.3.162 

Pipes and piping 

Aboveground 6.2 

Bends 6.5, A.6.5.3 

Branch see Branch lines 

Buildings, in see Buildings, Piping in 

Bypass 5.8.5 

Clearances, underground piping 6.1.1 

Concealed 

In buildings 6.3 

Definition 3.3.52 

Connections see Connections; Connectors 

Control see Control piping 

Defects 5.6.5, 7.1 .5 

Definition 3.3.163, 3.3.165 

Drips 6.6 

Equivalent length (definition) 3.3.164 

Floors, in 6.3.5 

Hangers and anchors 6.2.6 

Identification, multiple meter installations 5.7.5 

Independent 9.2.1 

Inspection, testing, and purging Chap. 7 

Installation 5.1.1, Chap. 6, 8.5.8 

Joining methods 5.6, A.5.6 

Materials 5.6, A.5.6 

MetaUic see Metallic pipe 

Oudets 6.7 

Partitions, in 6.3.3, 6.3.4 

Plastic see Plastic pipe 

Prohibited devices in 6.10 

Prohibited locations 6.2.5 

Protection, underground piping 6.1.2 

Protective coating 5.6.2.5, 5.6.3.3, 5.6.6 

Removal of 6.2.7 

Sediment traps 8.5.7 

Sizing and capacities of 5.4.1, 5.4.3, 8.1.16, 

Chap. 12, Tables 12.1 to 12.32, Chap. 13, A.5.4, A.5.4.1, 
Annex C 
Equations 12.3, A.12.3.1, A.12.3.2, C.4, C.5 



Examples C.7 

Methods 12.1, A.12.1.1, A.12.1.2, C.3, C.7 

Overpressure relief devices 5.9.8 

Sizing charts, use of C.6 

Sloped 6.2.3, 6.2.4 

Strain on 8.1.17 

Supports see Supports, Pipes and piping 

System 3.3.166 

Turns 6.5, A.6.5.3 

Underground 6. 1 , A.6. 1 .3 

Used materials 5.6.1.2 

Valves 6.9 

In vertical chases 6.4 

Workmanship 5.6.5 

Pipe threads, metallic 5.6.2.4, 5.6.7, Table 5.6.7.3; See a/50 Thread 

joint compounds 

Piping systems, gas Chap. 5 

Addition to existing 5.1.2 

Definition 3.3.166 

Design pressure 

Allowable pressure drop 5.4.1, 5.4.4, A.5.4.1, C.6 (4) 

Maximum 5.5.1 

Flexibility 5.13 

Gas-air mixtures 

Flammable 6.12, A.6.12 

Outside the flammable range 6.11 

Interconnections between 5.3 

Leakage tests 7.1.5, 7.2 

Local conditions, consideration of 5.13.2 

Materials and joining methods 5.6, A.5.6 

Operating pressure limitations 5.5, A.5.5.1 (1) 

Maximum A.5.5.1 (1 ) 

Placing in operation, purging for 7.3.2 

Plan 5.1 

Point of delivery, location of 5.2 

Pressure drop, allowable 5.4.1, 5.4.4, A.5.4.1, A.5. 4.4, C.6(4) 

Pressure testing and inspection 7.1, A.7.1.1 

Purging 7.3, Table 7.3.1, Table 7.3.2 

Removal from service, purging for 7.3.1 

Sizing of 5.4, 12.2, Table 12.2, A.5.4, Annex C 

Thermal expansion 5.13 

Plastic pipe 5.6.4, 5.6.9 

Within chimney flue 10.5.8 

Connection of 6. 1 . 7. 1 , 6. 1 .7.2 

Sizing Tables 12.19 to 12.21, Table 12.31, Table 12.32 

Tracer wire to locate 6.1.7.3 

Turns 6.5.2 

As vent material 10.4.2 

Plenums (definition) 3.3.167; see also Furnace plenums 

Point of delivery, location of 5.2 

Pool heaters 9.21 

Definition 3.3.168 

Power, continuous 8.6.4 

Power burners see Burners 

Pressure 

Atmospheric (definition) 3.3.16 

Back 

Definition 3.3.21 

Protection 5.10 

Definition 3.3.169 

Design see Design pressure 

High pressure gas pipe sizing 

Formula 12.3.2, A.12.3.2, C.4(l) 

Sizing charts, use of C.6(6) , Fig. C.6(b) 

Tables C.2.5 

Hybrid pressure pipe sizing method 12.1.3 

Limitations A.5.5.1 (1 ) 

Low pressure gas pipe sizing 

Formula for 12.3.1, A.12.3.1, C.4(2) 

Sizing charts, use of C.6(5), Fig. C.6(a) 

Tables C.2.2 

Low-pressure protection 5.11 



2002 Edition 



ANSIZ223.1-153 



INDEX 



54-153 



Maximum working 

Definition 3.3.144 

Overpressure relief device and 5.9.5 

Operating, limitations on 5.5 

Pressure control (deflnition) K.1.34 

Pressure drop 

Allowable 5.4.1, 5.4.4, A.5.4.1, A.5.4.4, C.6(4) 

Definition 3.3.170 

Pressure limiting devices 9.3.4, 9.21 .3, 9.28.3 

Definition 3.3.171 

Pressure regulators see Overpressure protection devices; 

Regulators 

Pressure relief devices 9.3.6, 11 .5, A.9.3.6; see also Overpressure 

protecfion devices 
Water heaters 9.28.5 

Pressure relief valves see Valves, Pressure relief 

Pressure tests 7.1, A.7.1.1 

Definition 3.3.172 

Primary air 11.2,A.11.2 

Definition 3.3.173 

Process air 8.1.7 

Protection 

Back pressure 5.10 

Control piping 5.9.4 

Floor furnaces 9.11.10 

Gas pressure regulators 5.8.4 

Gas utilization equipment 8.1.23 

From fumes or gases 8.1.6, A.8.1.6 

Physical 8.1 .13, 8.5.1 (7) 

Low-pressure 5.11 

Meters, gas 5.7.4 

Open-top broiler units 9.19.3 

Piping, underground 6.1.2 

Pool heaters 9.21 .1 

Protective devices 11.5 

Pui^e/pui^g 7.3, Table 7.3.1, Table 7.3.2, 9.8.8, A.7.3 

Definition 3.3.174 



Qualified agency 4.1 

Definition 3.3. 1 75 

Quick-disconnect devices 6.7.1.6, 6.7.2 Ex. 2, 8.5.5 

Definition 3.3.176 



-R- 

Radiant appliances see Decorative appliances, to install in vented 

fireplaces 

Ranges see Food service equipment, gas 

References Chap. 14, Annex L 

Refrigeration systems 

Boilers used with 9.3.9 

Coils 9.3.8, A.9.2.6 

Duct furnaces used with 9.10.6 

Refrigerators, gas 9.22 

Definition 3.3.178 

Venting 10.2.2(6) 

Regulations, gas supplier 1.1.2 

Regulators 

Appliance pressure 5.8.5.2 

Draft see Draft regulators 

Gas appliance 8.1.18,8.1.19 

Adjustable (definition) K.1.35 

Definition 3.3.179 

Illuminadng appliances 9.16.5 

Multistage (definition) K.1.36 

Nonadjustable (definition) K.1.37 

Venting of 8.1 .19 

Gas equipment 5.8.1, 5.8.3, 5.8.4 

Venting 5.8.5.2 

Line gas 5.8.1 to 5.8.4 



By-pass piping 5.8.6 

Definition 3.3.180 

Identification 5.8.7 

Venting 5.8.5.1 

Monitoring (definition) 3.3.181 

Pressure 5.8, 6.4.1, 8.1.18, 8.1.19, A.5. 8 see ai$o Overpressure 

protection devices; subhead: Gas appliance 

Definition 3.3.182 

Venting of 8. 1 . 19 

Protection of 5.8.4 

Series (definition) 3.3.183 

Service (definition) 3.3.184 

Regulator vents (deHnition) 3.3.185 

Relief openings 

Definition 3.3.186 

Industrial air heaters 9.8.7, 9.9.7 

Relief valves see Valves, Relief 

Repairs, gas shutoff prior to 4.2.2 

Residential board and care occupancy (definition) 3.3. 154 

Retroactivity of code 1.3 

Risers 

Anodeless see Anodeless risers 

Corrosion, protection against 6.3.5.2 

Roofs, gas utilization equipment on 8.4 

Room heaters 9.23 

Institutions, installations in 9.23.2 

Prohibited installations 9.23.1, A.9.23.1 

Unvented 9.23.1, 10.2.2(7), A.9.23.1 

Closed front wall heater (definition) K.1.44 

Definition 3.3.1 87 

Unvented circulator (definidon) K.1.38 

Vented 

Definition K.l .39 

Overhead heater (definition) K.1.42 

Vented circulator 

Definition K.1 .40 

Fan type (definition) K. 1 .41 

Wall 9.23.4 

Wall heater, unvented closed front (definition) K.1.43 

Room lai^e in comparison with size 

of equipment (definition) 3.3.188 



Safety blowouts (backfire preventers) 6.12.1 (4), 6.12.6, A.6.12.4 

Definition 3.3.189 

Safety inspection, existing appliance installation Annex H 

Safety shutoff devices 9.4.6, 11.3; see also Valves, 

Equipment shutoff 

Definition 3.3.190 

Unlisted LP-gas equipment used indoors 8.1.4 

Scope of code 1.1 

Seepage pan 9.11 .9 

Separate users, interconnections between 5.3.1 

Service head adapters (definition) 3.3.191 

Service meter assembly (definition) 3.3.192 

Service regulators (definition) 3.3.184; see also 

Regulators, Pressure 

Service shutoff valves see Valves 

Shall (definition) 3.3.194 

Shutoff procedure 4.2; see also Safety shutoff devices; Valves 

Shutoff valves see Valves 

Sources of ignition see Ignition, Sources 

Spaces 

Surrounding chimney lining or vent 10.5.8 

Well-ventilated 10.2.4 

Specific gravity 

Definition 3.3.197 

Fixed orifices, flow of gas through F.l 

Sizing of gas pipe and C.2.4 

Standby fuels, interconnections for 5.3.2 

Steam cookers see Food service equipment, gas 



2002 Edition 



54-154 



NATIONAL FUEL GAS CODE 



ANSIZ223.1-154 



Steam generators see Food service equipment, gas 

Stress 

Definition 3.3.200 

Hoop (definition) 3.3.122 

Structural members, building 8.L8 

Supports 

Chimneys 10.5.6 

Floor furnaces 9.1 1.6 

Gas utilization equipment 8.1.8.3 

Gas vents 10.6.5 

Heaters, infrared 9.18.1 

Meters, gas 5.7.3 

Pipes and piping 5.13.2, 6.2.1, 6.2.6, Table 6.2.6.2 

Single-wall metallic pipe 10.7.6 

Vent connectors 10.10.10 

Suspended-type unit heaters 9.26.2. 1 

Switches, electrical supply line 9.2.7 

-T- 

Temperatiu"e limit controls/devices 9.3.4 

Floor furnaces 9.11.2 

Pool heaters 9.21.3 

Water heaters 9.28.4 

Temperature relief valves see Valves, Temperature relief 

Tensile strength (dejfinition) 3.3.201 

Termination, venting systems see Venting systems 

Testing, piping system 

Defects, pressure test for 7.1.5 

Leakage 

Pressure test for detection 7.1.5 

System and equipment test 7.2, A.7.2.3 

Pressure 7.1, A.7.1.1 

Thermostats 

Electric switch type (definition) 3.3.202 

Integral gas valve type (definition) 3.3.203 

Room temperature 8.7 

Thimbles 10.7.4.5,10.10.14.2 

Thread joint compounds 5.6.7.4 

Definition 3.3.204 

Toilets, gas-fiied 9.25, Table 10.4.1, Table 10.7.4.4 

Traps, sediment 8.5.7 

Trenches 6.1.2.2 

Tubmg 

Connections 6.3.2 

Definition 3.3.205 

Gas utilization equipment connections 8.5.1(2), 8.5.1(7) 

Low pressure gas pipe sizing tables C.2.2 

Metallic 5.6.3, 5.6.8.2, A.5.6.3.2, A.5.6.8.1 

Partitions, in 6.3.4 

Plasdc 5.6.4, 5.6.9 

Sizing and capacities of Tables 12.7 to 12.18, 

Tables 12.25 to 12.30, C.5, Table C.5(b), C.7.3 

Workmanship and defects 5.6.5 

Type B gas vents see Gas vents 

Type B-W gas vents see Gas vents 

Type L vents see Gas vents 

-U- 

Undei^ound piping 6. 1 , A.6. 1 .3 

Unit broilers 

Definition 3.3.209 

Open-top 9.19 

Unit heaters 9.26 

High-static pressure type (definition) 3.3.210 

Low-static pressure type (definition) 3.3.211 

Utility gases 

Definition 3.3.212 

Fixed orifices, flow of gas through F.1.1, Table F.l, Table F.4 

-V- 

Vacuum relief valves see Valves, Vacuum relief 



Valve members 

Definition 3.3.222 

Nondisplaceable (definition) 3.3.152 

Valves 

Accessibility of 6.9.2.1 

Automatic (definition) 3.3.214 

Automatic gas shutoff K.1 .44 

Bypass see Bypass valves 

Controlling multiple systems 6.9.2 

Definition 3.3.213 

Diaphragm type, bleed lines for 8.1.20 

Equipment shutoflF 5.12, 6.7.2.2, 8.5.4, 10.5.5.2 

Definition 3.3.215 

Gas-mixing machines 6.12.5.4, A.6.12.5.4 

Manual 6.9, A.6.12.5.4 

Individual main burner (definition) K.1.45 

Main burner control (definition) K.1.46 

Manual main gas control 6.9.2.1 

Definition K.1 .47 

Manual reset 6.12.5.4 

Definition 3.3.216 

Mixing blowers 6.12.4, A.6.12.4 

Pressure relief 

Definition 3.3.217 

For steam and hot water boilers 9.3.6, A.9.3.6 

Relief (definition) 3.3.21 8 

Service shutoff 5.12 

Definition 3.3.219 

Emergency 6.9.3 

Manual 6.9, 8.5.4 

For multiple systems 6.9.2 

Temperature relief 9.28.5 

Definition 3.3.220 

Used 5.6.1.2 

Vacuum relief 9.28.5 

Definition 3.3.221 

Vapors, flammable, gas appliances in area of 8.1.9 

Vehicular fuel systems, compressed natural gas 9.29 

Vent(s) 

Definidon 3.3.223 

Gas see Gas vents 

Heater 9.8.6, 9.9.6 

Obstructions 10.15, 13.1.1 

Offset 13.2.5 

Definition 3.3.155 

Regulator (definition) 3.3.185 

Sizes 

Appliance categorized vent diameter/area (definition) . 3.3.11 

Multiple appHance vents 13.2, Tables 13.6 to 13.13, 

A.13.2.19 

Single appliance vents 13.1, Tables 13.1 to 13.5, A.13.1.7 

Toilets, gas-fired 9.25.3 

Vent connectors 10.10, 10.11, A.10.10.3, A.10.10.9.2 

Bends 10.10.6 

Chimneys see Chimneys 

Clearance 10.10.5 

Combination units A.10.5.5.3 

Dampers 10.13, 10.14 

Definition 3.3.224 

Fireplaces 10.10.13 

Inspection 10.10.12 

Joints 10.10.7 

Length 10.10.9, A.10.10.9.2 

Location 10.10.11 

Materials 10.10.2, Table 10.10.2.5, Table 10.10.2.6 

Maximum length 13.2.2, Table 13.2.2, 13.2.3 

Mechanical draft systems 10.3.4.4 

Obstructions 10.15 

Routing Table 13.2.2, 13.2.3 



2002 Edition 



ANSIZ223.1-155 



INDEX 



54-155 



Size of 10.10.3, 13.1.10, 13.1.11, 13.2.4, 13.2.8, 

A.10.10.3, Fig. G.1.1, Fig. G.1.2, Figs. G.l(b) to G.l(cl), 
Figs. G.l (f) to G.l (i) , Figs. G.l (k) to G.l (m) , Fig. G.2.1, 
Fig. G.2.2 

Slope 10.10.8 

Support 10.10.10 

Through ceilings, floors, or walls 10.10.14 

Toilets, gas-fired 9.25.3 

Two or more appliances 10.10.3.3, 10.10.3.4, 10.10.4 

Vent damper device, automatic 10.14; see also Dampers 

Definition 3.3.225 

Electrically operated 

Definition 3.3.226 

Mechanically operated 

Definition 3.3.227 

Thermally actuated 

Definition 3.3.228 

Vented appliances 

Category I Table 10.4.1, 10.5.1.3 Ex., 

10.5.3.1, 10.6.1(5), 10.9.2, 10.10, Chap. 13, Annex G 

Definition 3.3.230, A.3.3.230 

Category II Table 10.4.1, 10.8.4, 10.9.1 

Definition 3.3.231 

Category III Table 10.4.1, 10.8.4, 10.9.2 

Definition 3.3.232 

Category IV Table 10.4.1, 10.8.4, 10.9.1 

Definition 3.3.233 

Vented waU furnaces 9.27.1.3, 9.27.1.4, Table 10.4.1 

Definition 3.3.234 

Fan-type (definition) K.1 .48 

Gravity-type (definition) K.1.49 

Vent gases (definition) 3.3.229 

Ventilating hoods 9.19.3, 10.2.3, 10.3.5, 10.6.2(1) (f), A.10.3.5 

Ventilation 

Air for 8.3, A.8.3 

Opening design, example of Annex J 

Chase 6.4.3, A.6.4.3 

Food service equipment 9.12.8, A.9.12.8 

Gas utilization equipment 8.1.2(1) 

Industrial air heaters 9.8.3.3, 9.8.5, 9.9.5, A.9.9.5 

Infrared heaters 9.18.3 

Open-top broiler units 9.19.3, 9.19.4 

Venting Chap. 10 

Definition 3.3.235 

Equipment not requiring venting 10.2.2 

Fl ue gases 8.1.14 

Overpressure protection devices 5.9.7 

Pressure regulators 5.8.5, 6.4.1, 8.1.19 

Venting systems 

Connection to see Vent connectors 

Definition 3.3.236, A.3.3.236 

Design and construction 10.3 



Gas utiHzation equipment 8.1.2(3), 8.1.14 

Mechanical draft 

Definition 3.3.237 

Forced (definition) 3.3.238 

Induced (definition) K.1.50 

Power (definition) K.1.51 

Natural draft (definition) 3.3.239 

Pool heaters 9.21 .5 

Refrigerators 9.22.2 

Sizing of 

Appliances equipped with draft hoods or listed for use with 

Type B vent Annex G 

Category I appliances 10.5.3.1, Chap. 13, Annex G 

Specification for 10.2 

Termination 

Chimneys 10.5.2 

Gas vents 10.6.2 

Mechanical draft systems 10.3.4.6 

Single-wall metal pipe 10.7.3 

Through the wall 10.8, A.10.8 

Two or more appliances, single vent 10.10.3.3 to 10.10.3.6, 

10.10.4, 13.2.17 

Type of system to use 10.4, Table 10.4.1 

Vented appliances see Vented appliances 

Ventilating hoods A.10.2.3 



-W- 

WaU furnaces 9.27 

Direct vent (definition) 3.3.240 

Vented see Vented wall furnaces 

Wall head adapter (definition) 3.3.241 

Wall room heaters 9.24.4 

Unvented closed front (definition) K. 1 .44 

Water heaters 9.28 

Anti-siphon devices 9.28.8, A.9.28.8 

Automatic circulating tank (definition) K.1.52 

Automatic instantaneous type 9.28.6 

Definition K.1.53 

Circulating tank type 9.28.7 

Coil circulation (definition) K.1.54 

Commercial storage (definition) K.1. 55 

Countertop domestic storage (definition) K. 1 .56 

Definition 3.3.242 

Domestic storage (definition) K.1. 57 

Nonautomatic circulating tank (definition) K.1. 58 

Venting 10.2.2(5), 13.1.9(5), Annex G 

Weather conditions 5.13.2, 6.2.3 

Floor furnaces and 9.11.10 

Protection against 6.1.4, A.6.1.4 

Single-wall metal pipe, use of 10.7.2 

Work interruptions 4.2.2 



Cou/W 



5 6 06 



2002 Edition 



:■ :yC! '!:•':' -i-^^H; ;f;■-^■■::- ;r '■[■^^i-^- v Tentative Interim-Aiilendmmt'''- 'i^"^; ''■ y-'^ ■'--'■■ ■■-■-r ■;;■'■■;' ^:- " 

Pursuant to Section ,5 of the NFPA Regulations .Governing Gornmittee Projects, the National 
FireProtectiori Association has issued the following Tentative Interirh Amendmisril to NFPA 54, 
NationalFuerGas'Code, 2002 edition.' TheTIA was processed by the National Fuel Gas Code 
Gommittee, aridj^^^^ by the Standards Council on April 3, 2003, with an effective date of 

^ April ?23,.2003.l'^LI^ IT- 'v f ■ ^'^ - ^ ^^ ..^ ^-- ^r '—^' -^'^'^^ ■■: ■•---:-.; -■■ '-- ; - ^ '^-^■^^;-^- -- -^^ v" ■■ - 

A Tentative Interirh Artiiehdnient is tentative because it has not been prbcessed through the en- 
tire standa;rds-making procedures.. It is interimbecause it is effective only between editions of ; 
the standard. ATM automatically beeorhes a proposal of the proponent for thie next edition of 
the stahdard;' as such; it then is subject, to all of the procedures of the stahdards-making process. 

i 1. Revise 8.3; 7:to, read as folloxvs:. ■- v ■' •■■■ r '•■'■-■ ''■■'^- - -^- ■: ■'>-^;^■■:i^;;•■'■'■■^ ■*"-■■ ^•■-- '^■■■'^ ■ ;--V'^--' ^^ '■■ 
^8J3.7 Lom^rs a«^'Grilles'and^cr^^ \,_',i :.. i, ^. .1 [.'... ;-..l\y-[ i^ . - .u; ■.' ^-> -- Jv ... '■■ T- :■■■ " '- 

8.3.7.1 Louvers and Grilles. The, required size of openings for combustion, ventilation, and dilu- 
tion air shall be based on the net free area of each opening. Where: the free area through a de- 
sign* of louver ©* grille or screen is known, it shalf be used in calculating the size opening re- 
quired to provide the free area specified. Where the louver and grille design and free areaare 
not known, it shall be assumed that wood louvers will have. 25 percent free areia and metal lou- 
vers and grilles will have 75 percent free area. Nohmotorized louvers and grilles shall be fixed in 

■ the bperi position ^ : '; '" ; " '■ ^ ' ^' v' ':: "" ' ' ' 7 .■' '.: ^ ',;:.:/■..... ,■ :■,/.■ ^ ..„.,;■-;. ^. . .. .,.., .-, 

8.3.7.2 M iniTnum Screen Mesh Size. Screens shall not be smaller than V4-inch mesh. - - 

Renumber 8.3iT^2 as 83.7.3. ' ' '■ * T .^ ■■..• r !; - ■.- '. '. ■' -■■,:' l J,. .■■ . - . ': .i. ; ; -.. :,::...%...;., 



:'■ "C6pyrigHt©'20p3AirRightsReserveci *: V 
-NATIONAL FIRE PROTEGTION' ASSOCIATION 



Sequence of Events Leading to PubUcatian 
tf an NFPA Committee Document 

Call goes out for proposals to amend existing document or for 
recommendations on new document 



Committee meets to act on proposals, to develop its own pro- 
posals, and to prepare its report 



Committee votes on proposals by letter ballot If two^hirds ap- 
prove, report goes forward. Lacking two-thirds 
approval, report returns to committee. 



Report — Report on Proposals (ROP) — is published for public 
review and comment 



Committee meets to act on each public comment received. 



Committee votes on comments by letter ballot If two-thirds 

improve, supplementary report goes forward. 

Lacking two-thirds approval, supplementary report returns to 

committee. 



Supplementary report — Report on Comments (ROC) — is pub- 
lished for public review. 



NFPA membership meets (Annual or Fall Meeting) and acts 
on committee report (ROP or ROC). 



Committee votes on any amendments to report approved at 
NFPA Annual or Fall Meeting. 



Appeals to Standards Council on Association action must be 
filed within 20 days of the NFPA Annual or Fall Meeting. 



Standards Council decides, based on all evidence, \^ether 

or not to issue standard or to take other action, including 

upholding any appeals. 



Committee Membership Class^ications 

The following classifications apply to Technical Commit- 
tee members and represent their principal interest in the 
activity of a committee. 

M Mantf/ZzcturerrA representative ofa maker or marketer of 
a product assembly, or system, or portion thereof, that 
is affected by the standard. 

U User A representative of an entity that is subject to the 
provisions of the standard or that voluntarily uses the 
standard. 

I/M InstaUer/MaiTitainer A representative of an entity that is 
in the business of installing or maintaining a product as- 
sembly, or system affected by the standard. 

L Labor A labor representative or employee concerned 
with safety in the workplace. 

R/T Applied Research/Testing Laboratory: A representative of 
an independent testing laboratory or independent ap- 
plied research organization that promulgates and/or 
enforces standards. 

£ Enforcing Authority: A representative of an agency or 
an organization that promulgates and/or enforces 
standards. 

I Insurance: A representative of an insurance company, 
broker, agent bureau, or inspection agency. 

C Consumer A person who is, or represents, the ultimate 
purchaser of a product system, or service affected by the 
standard, butM^oisnotinduded in the ^5ercIassification. 

SE Special Expert: A person not representing any of the pre- 
vious classifications, but who has special expertise in the 
scope of the standard or portion tiiereof. 

NOTE 1: 'Standard' connotes code, standard, recommended 
practice, or g^de. 

NOTE 2: A representative includes an employee. 

NOTE 3: While these classifications will be used by the Stan- 
dards Council to achieve a balance for Technical Committees, 
the Standards Council may determine that new dasafications 
of members or unique interests need representation in order 
to foster the best possible committee deliberations on any 
project In this connection, die Standards Council may make 
such appointments as it deems appropriate in the public inter- 
est such as the classification of 'TJtilities'' in the National Elec- 
trical Code Committee. 

NOTE 4: Representatives of subsidiaries of any group are gen- 
erally considered to have the same classification as die parent 
organization. 



9/99A 



FORM FOR PROPOSALS ON NFPA TECHNICAL COMMITTEE DOCUMENTS 

Mail to: Secretary, Standards Council 

National Fire Protection Association, 1 Batterymarch Park, Quincy, Massachusetts 02269-9101 
Fax No. 617-770-3500 

Note: All proposals must be received by 5:00 p.m. EST/EDST on the published proposal-closing date. 



If you need further information on the standards-making process, please contact the 

Standards Administration Department at 617-984-7249. 

For technical assistance, please call NFPA at 617-770-3000 



Please indicate in which format you wish to receive your ROP/ROC: D paper D electronic D download 

(Note: In choosing the download option you intend to view the ROP/ROC from our website; no copy will be sent to you.) 



Date 



Name 



Tel. No. 



Company 



Street Address 



Please Indicate Oi^anization Represented (if any). 

1. a) NFPA Document Title 

b) Section/Paragraph 



NFPA No. & Year 



2. Proposal Recommends: (Check one) Q new text 

Q revised text 
Q deleted text 



FOR OFFICE USE ONLY 
Log# 



Date Rec'd 



3. Proposal (include proposed new or revised wording, or identification of wording to be deleted): (Note: Proposed 
text should be in legislative fomiat: i.e., use underscore to denote wording to be inserted (inserted wording^ and strike-throu^ to denote wording to 
be deleted (dolotpd wording) . 



4. Statement of Problem and Substantiation for Proposal: (Note: State the problem that will be resolved by your recommenda- 
tion; give the specific reason for your proposal including copies of tests, research papers, fire exp^ence, etc. If more than 200 words, it may be 
abstracted for publication.) 



5. Q This Proposal is original material. (Note: Original material is considered to be the submitter's own idea based on or as a result of 
his/her own experience, thought, or research and, to the best of his/her knowledge, is not copied from another source.) 

Q This Proposal is not ordinal material; its source (if known) is as follows: 

Note 1: Type or print legibly in black ink. 

Note 2: If supplementary material (photographs, diagrams, reports, etc.) is included, you may be required to submit sufficient copies for all mem- 
bers and alternates of the technical committee. 

/ hereby grant the NFPA all and full rights in copyright, in this proposal, and I understand that I acquire no 

rights in any publication of NFPA in which this proposal in this or another similar or analogous form is used. 



Signature (Required) 



PLEASE USE SEPARATE FORM FOR EACH PROPOSAL 



9/99C 



NOTICES 

All questions or other communications relating to this document should be sent to the American Gas Association or 
the National Fire Protection Association Headquarters, addressed to the attention of the Committee responsible for the 
document. 

For information on obtaining Formal Interpretations of the document, proposing amendments for Committee consid- 
eration, and appeals on matters relating to the content of the document, write to the Secretary, Accredited Standards 
Committee Z223, 400 N. Capitol Street, N.W., Washington, DC 20001 and the Secretary, Standards Council, National 
Fire Protection Association, 1 Batterymarch Park, P.O. Box 9101, Quincy, MA 02269-9101. 

Users of this document should be aware that this document may be amended from time to time through the issuance 
of Tentative Interim Amendments, and that an official AGA or NFPA document at any point in time consists of the cur- 
rent edition of the document together with any Tentative Interim Amendments then in effect. In order to determine 
whether this document is the current edition and whether it has been amended through the issuance of Tentative Interim 
Amendments, consult appropriate NFPA publications such as the National Fire Codes, Subscription Service, visit the 
NFPA website at www.nfpa.org, or contact the AGA or NFPA at the addresses listed above. 

A statement, written or oral, that is not processed in accordance with the interpretation procedure of the Z223 Commit- 
tee or with Section 6 of the NFPA Regulations Governing Committee Projects shall not be considered the position respec- 
tively of the Z223 Committee or the NFPA, and shall not be considered nor be relied upon as a Formal Interpretation. 

The AGA and the NFPA do not take position with respect to the validity of any patent rights asserted in connection 
with any items which are mentioned in or are the subject of this document, and the AGA and the NFPA disclaim liabil- 
ity for the infringement of any patent resulting from the use of or reliance on this document. Users of this document are 
expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, 
is entirely their own responsibility. 

Users of the document should consult applicable federal, state, and local laws and regulations. The American Gas As- 
sociation and the National Fire Protection Association do not, by the publication of this document, intend to urge action 
that is not in compliance with applicable laws, and this document may not be construed as doing so. 



8/02 



American Gas Association 

The American Gas Association represents 187 local energy utility companies that deliver 
natural gas to more than 52 million homes, businesses and industries throughout the United 
States. AGA member companies account for 83 percent of all natural gas delivered by local 
natural gas distribution companies. AGA is an advocate for local natural gas utility companies 
and provides a broad range of programs and services for member natural gas pipelines, 
marketers, gatherers, international gas companies and industry associates. Natural gas meets 
one-fourth of the United States' energy needs and is the fastest growing major energy source. 

One of AGA's primary missions is to encourage and assist its members in sharing information 
designed to achieve operational excellence by improving their efficiency, reliability and safety. 
AGA fulfills part of that mission by serving as an ANSI approved Secretariat on key technical 
publications. AGA's ANSI documents include: 

• ANSI approved Secretariat and co-sponsor of the National Fuel Gas Code. 

• ANSI approved Secretariat of the ASC B1 09 Committee that publishes four standards on 
gas 

displacement meters and service regulators. 

• ANSI approved Secretariat of the ASC Z380 Committee that publishes the Guide for Gas 
Transmission and Distribution Piping Systems. 

For publication information contact the American Gas Association's publication fulfillment 
facility toll free at (866) 816-9444 or visit us on the web at www.aga.org. For more information 
on association activities or membership contact: American Gas Association, 400 N. Capitol 
Street, N.W., Washington, DC 20001 (202/824-7000 or FAX 202/824-7115). 

NFPA IVIembership 

When you join NFPA, you join thousands of professionals worldwide in the fight against loss of 
life and property from fire. 

There are many membership benefits, including full voting rights in the code-making process at 
the NFPA World Safety Congress and Exposition® in May or at the Fall Education Conference™ 
in November, and free subscriptions to the NFPA Journal®, NFPA Journal Buyers' Guide, and 
the NFPA News and NFPA Update newsletters. As a member, you will also receive a 10% 
discount on all the NFPA products and services - including videos, seminars, meeting and 
registration fees, and much more! 

To order or for more information on other NFPA products or seminars, call toll-free 
at 1-800-344-3555 or visit our online catalog at www.nfpacatalog.org 



Reorder code: 2Z