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Full text of "Connecticut Mechanical Code"

TABLE OF CONTENTS 

STATE BUILDING CODE 

2005 CONNECTICUT SUPPLEMENT 

Repealed 29-252-1 c 

State Building Code - Connecticut Supplement 29-252-1 d 

Section Page 

Amendments to the 2003 International Building Code 2 

Amendments to the ICC/ANSI A1 1 7. 1 - 2003 63 

Amendments to the 2003 International Existing Building Code 65 

Amendments to the 2003 International Plumbing Code 74 

Amendments to the 2003 International Mechanical Code 81 

Amendments to the 2003 International Energy Conservation Code 87 

Amendments to the 2003 International Residential Code 90 

Amendments to the 2005 NFPA 70 National Electrical Code 112 



81 



AMENDMENTS TO THE 2003 INTERNATIONAL MECHANICAL CODE 

CHAPTER 1 -ADMINISTRATION 

(Amd) 101.1 Title. These regulations shall be known as the 2003 International Mechanical 
Code portion of the 2005 State Building Code, hereinafter referred to as "the code" or "this 
code". 

(Amd) 101.2 Scope. This code shall regulate the design, installation, maintenance, alteration 
and inspection of mechanical systems that are permanently installed and utilized to provide 
control of environmental conditions and related processes within buildings. This code shall also 
regulate those mechanical systems, system components, equipment and appliances specifically 
addressed herein. The installation of fuel gas distribution piping and equipment, fuel-gas-fired 
appliances and fuel-gas-fired appliance venting systems shall be in accordance with Section 
101.2.2. 

Exceptions: 

1. Detached one- and two-family dwellings and multiple single-family dwellings 
(townhouses) not more than three stories high with separate means of egress and their 
accessory structures shall comply with the 2003 International Residential Code. 

2. Mechanical systems in existing buildings undergoing repair, alteration, addition or 
change of occupancy shall be permitted to comply with the 2003 International Existing 
Building Code. 

(Amd) 101.2.1 Appendices. The provisions of Appendix A shall be considered applicable to 
the utilization of this code. 

(Add) 101.2.2 Fuel gas. The 2003 International Fuel Gas Code is not adopted by the State of 
Connecticut. In addition to the requirements of this code, the installation and operation of gas 
equipment and piping shall comply with sections 29-329, 29-330 and 29-331 of the Connecticut 
General Statutes, and the regulations known as the Connecticut Gas Equipment and Piping 
Code adopted by the Commissioner of Public Safety under authority of section 29-329 of the 
Connecticut General Statutes, and the regulations known as the Connecticut Liquefied 
Petroleum Gas and Liquefied Natural Gas Code adopted by the Commissioner of Public Safety 
under authority of section 29-331 of the Connecticut General Statutes. References to the 
International Fuel Gas Code within the body of the model document shall be considered to be 
references to such statutes and regulations. 

(Add) 101.2.3 Oil-burning equipment, piping and storage. In addition to the requirements of 
this code, the installation of oil burners and equipment used in connection therewith, including 
tanks, piping, pumps, control devices and accessories shall comply with sections 29-316 and 
29-317 of the Connecticut General Statutes, and the regulations known as the Connecticut Oil 
Burning Equipment Code adopted by the Commissioner of Public Safety under authority of 
section 29-317 of the Connecticut General Statutes. 

(Add) 101.2.3.1 Local regulations. Pursuant to section 29-316 of the Connecticut General 
Statutes, the warden or burgesses of a borough, the selectmen of a town, the common council 
of a city or the commissioners of a fire district may enact rules and regulations for the 
installation of fuel oil burners, equipment therefore and fuel oil storage tanks. 

(Add) 101.2.4 Electrical. The 2003 ICC Electrical Code is not adopted by the State of 
Connecticut. The provisions of the 2005 NFPA 70 National Electrical Code shall apply to the 
installation of electrical systems, including alterations, repairs, replacement, equipment, 
appliances, fixtures, fittings and appurtenances thereto. References to the 2003 ICC Electrical 



82 



Code within the body of the model document shall be considered to be references to the 2005 
NFPA 70 National Electrical Code. 

(Amd) 101.2.5 Fire prevention. References to the 2003 International Fire Code within the body 
of the model document shall be considered to be references to the 2005 Connecticut State Fire 
Safety Code. 

(Amd) 102.6 Historic buildings. Pursuant to section 29-259 of the Connecticut General 
Statutes, exemptions may be granted to the provisions of this code for historic structures, as 
defined by section 10-320c of the Connecticut General Statutes, which have been classified as 
such in the State Register of Historic Places, as long as the provisions of subsection (b) of 
section 29-259 of the Connecticut General Statutes are adhered to and provided that such 
exemptions shall not affect the safe design, use or construction of such property. 

(Del) SECTION 103 - DEPARTMENT OF MECHANICAL INSPECTION. Delete Section 103 in 
its entirety and replace with the following: 

(Add) SECTION 103 - ENFORCEMENT AGENCY 

(Add) 103.1 Creation of enforcement agency. Each town, city and borough shall create an 
agency whose function is to enforce the provisions of this code. The official in charge thereof 
shall be known as the building official. 

(Add) 103.2 Appointment. The chief executive officer of any town, city or borough shall 
appoint an officer to administer this code, and this officer shall be known as the "building official" 
in accordance with section 29-260 of the Connecticut General Statutes, and referred to herein 
as the building official, local building official, or code official. 

(Add) 103.3 Employees. In accordance with the prescribed procedures and regulations of the 
town, city or borough and with the concurrence of the appointing authority, the building official 
shall have the authority to appoint an assistant building official, related technical officers, 
inspectors, plan examiners and other employees. Such employees shall have the powers as 
regulated by the town, city or borough, and by the State of Connecticut. 

(Add) 103.4 Restriction of employees. An official or employee connected with the agency 
created to enforce the provisions of this code pursuant to Section 103.1 , except one whose only 
connection with it is that of a member of the board of appeals established under the provisions 
of Section 112, shall not be engaged in or directly or indirectly connected with the furnishing of 
labor, materials or appliances for the construction, addition, alteration, repair or maintenance of 
a building located in the town, city or borough in which such official or employee is employed, or 
the preparation of construction documents therefore, unless that person is the owner of the 
building. Such officer or employee shall not engage in any work that conflicts with official duties 
or with the interests of the agency. 

(Amd) 104.1 General. The building official is hereby authorized and directed to enforce the 
provisions of this code. The building official shall have the authority to adopt policies and 
procedures in order to clarify the application of its provisions. Such policies and procedures 
shall be in compliance with the intent and purpose of this code. Such policies and procedures 
shall not have the effect of waiving requirements specifically provided for in this code, nor shall 
they have the effect of establishing requirements in excess of those set forth in this code. 

(Amd) 104.2 Rule making authority. Pursuant to the provisions of subsection (a) of section 
29-252 of the Connecticut General Statutes, the State Building Inspector and the Codes and 
Standards Committee shall, jointly, with the approval of the Commissioner of Public Safety, 



83 

adopt and administer a State Building Code for the purpose of regulating the design, 
construction and use of buildings or structures to be erected and the alteration of buildings or 
structures already erected and make such amendments thereto as they, from time to time, 
deem necessary or desirable. 

(Amd) 104.5 Right of entry. In accordance with the provisions of subsection (d) of section 29- 
261 of the Connecticut General Statutes, the building official or his assistant shall have the right 
of entry to such buildings or structures, except single-family residences, for the proper 
performance of his duties between the hours of nine a.m. and five p.m., except that in the case 
of an emergency, he shall have the right of entry at any time, if such entry is necessary in the 
interest of public safety. On receipt of information from the local fire marshal or from any other 
authentic source that any building in his jurisdiction, due to lack of exit facilities, fire, 
deterioration, catastrophe or other cause, is in such condition as to be a hazard to any person 
or persons, the building official or his assistant shall immediately make inspection in accordance 
with the provisions of section 29-393 of the Connecticut General Statutes. 

(Amd) 105.1 Modifications. The State Building Inspector may grant variations or exemptions 
from, or approve equivalent or alternative compliance with the State Building Code where strict 
compliance with the State Building Code would entail practical difficulty or unnecessary 
hardship, or is otherwise adjudged unwarranted, provided that the intent of the law shall be 
observed and public welfare and safety be assured. Any person aggrieved by any decision of 
the State Building Inspector may appeal to the Codes and Standards Committee within 14 days 
after mailing of the decision in accordance with subsection (b) of section 29-254 of the 
Connecticut General Statutes. 

(Add) 105.1.1 Records. The application for modification, variation or exemption and the 
decision of the State Building Inspector shall be in writing and shall be officially recorded with 
the application for a building permit in the permanent records of the building department. 

(Add) 105.1.2 Accessibility exemptions. Any variation of or exemption from any provisions 
relating to accessibility to, use of and egress from, buildings and structures as required herein 
shall be permitted only when approved by the State Building Inspector and the Executive 
Director of the Office of Protection and Advocacy for Persons with Disabilities, acting jointly, 
pursuant to subsection (b) of section 29-269 of the Connecticut General Statutes. Any person 
aggrieved by the joint decision of the State Building Inspector and the Executive Director of the 
Office of Protection and Advocacy for Persons with Disabilities may appeal to the Codes and 
Standards Committee within 30 days after such decision has been rendered in accordance with 
subsection (b) of section 29-269 of the Connecticut General Statutes. 

(Add) 106.1.1 By whom application is made. Application for a permit shall be made by the 
owner in fee or by an authorized agent. If the application is made by a person other than the 
owner in fee, it shall be accompanied by an affidavit of the owner or a signed statement of the 
applicant witnessed by the building official or such official's designee to the effect that the 
proposed work is authorized by the owner in fee and that the applicant is authorized to make 
such application. If the authorized agent is a contractor, the provisions of section 20-338b of 
the Connecticut General Statutes shall be followed. The full names and addresses of the 
owner, agent and the responsible officers, if the owner or agent is a corporate body, shall be 
stated in the application. 

(Add) 106.2.1 State agency exemptions. A state agency shall not be required to obtain a 
building permit from the local building official. A state agency shall obtain a building permit for 
construction or alteration of state buildings or structures from the State Building Inspector in 
accordance with the provisions of section 29-252a of the Connecticut General Statutes. 



84 

(Amd) 106.4 Permit issuance. The building official shall examine or cause to be examined 
applications for permits and amendments thereto within 30 days after filing and either issue or 
deny a permit within such 30 day period. If the application or construction documents do not 
conform to the requirements of this code and pertinent laws, the building official shall reject 
such application in writing, stating the reasons therefore. If the building official is satisfied that 
the proposed work conforms to the requirements of this code and applicable laws, statutes, 
regulations and ordinances, the building official shall issue a permit therefore as soon as 
practicable. 

(Amd) 106.4.6 Retention of construction documents. One set of approved construction 
documents shall be retained by the building official for a period as set forth in the 
records/disposition schedule adopted pursuant to chapter 188 of the Connecticut General 
Statutes. 

Exception: In accordance with the provisions of subsection (e) of section 29-261 of 
the Connecticut General Statutes, upon receipt of a written request signed by the 
owner of plans and specifications on file for a single-family dwelling or out-building, the 
building official shall immediately return the original plans and specifications to the 
owner after a certificate of occupancy is issued with respect to the plans and 
specifications. 

(Del) 106.5.1 Work commencing before permit issuance. Delete without substitution. 

(Amd) 106.5.2 Fee schedule. Each municipality shall establish a schedule of fees for each 
construction document review, building permit, and certificate of occupancy. A schedule of 
adopted fees shall be posted for public view. 

(Amd) 106.5.3 Fee refunds. In the case of the revocation of a permit or abandonment or 
discontinuance of a building project, the portion of the work actually completed shall be 
computed and any excess fee for the incomplete work shall be returned to the permit holder 
upon written request. All plan examination and permit processing fees and all penalties that 
have been imposed on the permit holder under the requirements of this code shall first be 
collected. 

(Add) 107.1.3 Posting of required inspections. A schedule of required inspections shall be 
compiled by the code official. The schedule shall be posted in the building department for 
public view. 

(Add) 107.5 Notification of inspection and testing results. Notification as to passage or 
failure, in whole or in part, of any required inspection or test shall be made in writing by the 
building official or his duly authorized representative and shall be left at the job site or delivered 
to the permit holder. It shall be the duty of the permit holder to ascertain the results of required 
inspections. 

(Amd) 108.4 Violation penalties. Any person who violates any provision of this code shall be 
fined not less than two hundred nor more than one thousand dollars or imprisoned not more 
than six months or both, pursuant to section 29-254a of the Connecticut General Statutes. 

(Amd) 108.5 Stop work orders. Upon notice from the building official, work on any 
mechanical system that is being done contrary to the provisions of this code or in a dangerous 
or unsafe manner shall immediately cease. Such notice shall be in writing and shall be given to 
the owner of the property, or to the owner's agent, or to the person doing the work. The notice 
shall state the conditions under which the work is authorized to resume. Where an emergency 
exists, the building official shall not be required to give a written notice prior to stopping the 
work. Any person who shall continue any work in or about the structure after having been 



85 

served with a stop work order, except such work as that person is directed to perform to remove 
a violation or unsafe condition, shall be liable for penalties in accordance with Section 108.4. 

(Del) SECTION 109 - MEANS OF APPEAL. Delete this section in its entirety and replace with 
the following: 

(Add) 1 09.1 Means of appeal. Means of appeal shall be in accordance with Section 11 2 of the 
2003 International Building Code portion of the 2005 State Building Code. 

CHAPTER 2 - DEFINITIONS 

(Amd) 201.3 Terms defined in other codes. Where terms are not defined in this code and are 
defined in other portions of the 2005 State Building Code, such terms shall have the meanings 
ascribed to them as in those codes. 

(Add) 202.1 Definitions. Add or amend the following definitions: 

(Add) BUILDING OFFICIAL. The officer or other designated authority charged with the 
administration and enforcement of this code, or a duly authorized representative. Also known 
as the local building official or code official. 

(Amd) REGISTERED DESIGN PROFESSIONAL. An architect, engineer or interior designer, 
registered or licensed to practice professional architecture, engineering or interior design, as 
defined by the statutory requirements of the professional registration laws of the State of 
Connecticut, and acting within the scope of his or her practice. 

CHAPTER 3 - GENERAL REGULATIONS 

(Amd) 301.1 Scope: Except as may be otherwise regulated by Chapters 540 and 541 of the 
Connecticut General Statutes, or regulations of other state agencies, this chapter shall govern 
the approval and installation of all equipment and appliances that comprise parts of the building 
mechanical systems regulated by this code in accordance with Section 101.2. 

(Amd) 301.3 Fuel gas appliances and equipment. The 2003 International Fuel Gas Code is 
not adopted by the State of Connecticut. In addition to the requirements of this code, the 
installation and operation of gas equipment and piping shall comply with sections 29-329, 29- 
330 and 29-331 of the Connecticut General Statutes, and the regulations known as the 
Connecticut Gas Equipment and Piping Code adopted by the Commissioner of Public Safety 
under authority of section 29-329 of the Connecticut General Statutes, and the regulations 
known as the Connecticut Liquefied Petroleum Gas and Liquefied Natural Gas Code adopted 
by the Commissioner of Public Safety under authority of section 29-331 of the Connecticut 
General Statutes. References to the International Fuel Gas Code within the body of the model 
document shall be considered to be references to such statutes and regulations. 

(Amd) 301.7 Electrical. The 2003 ICC Electrical Code is not adopted by the State of 
Connecticut. The provisions of the 2005 NFPA 70 National Electrical Code shall apply to the 
installation of electrical systems, including alterations, repairs, replacement, equipment, 
appliances, fixtures, fittings and appurtenances thereto. References to the ICC Electrical Code 
within the body of the model document shall be considered to be references to the 2005 NFPA 
70 National Electrical Code. 



86 



CHAPTER 6 - DUCT SYSTEMS 



(Amd) 606.2 Where required. Smoke detectors shall be installed where indicated in Sections 

606.2.1 through 606.2.3. 

Exception: Smoke detectors shall not be required where air distribution systems are 
incapable of spreading smoke beyond the enclosing walls, floors and ceilings of the 
room or space in which the smoke is generated, or where the sole purpose of the air 
distribution system is to remove air from the inside of the building to the outside of the 
building. 

(Amd) 606.2.1 Supply air systems. Smoke detectors shall be installed in supply air systems 
with a design capacity greater than 2,000 cubic feet per minute in the supply air duct 
downstream of any filters and ahead of any branch connections. 

(Amd) 606.2.2 Common supply and return air systems. Where multiple air-handling systems 
share common supply or return air ducts or plenums with a combined design capacity greater 
than 2,000 cubic feet per minute, the supply air system shall be provided with smoke detectors 
in accordance with Section 606.2.1. 

Exception: Individual smoke detectors shall not be required for each fan-powered 
terminal unit, provided that such units do not have an individual design capacity greater 
than 2,000 cubic feet per minute and will be shut down by the activation of the smoke 
detectors required by Section 606.2.1. 
In all cases the smoke detectors shall comply with Sections 606.4 and 606.4.1. 

(Amd) 606.2.3 Return air risers. Where return air risers serve two or more stories and serve 
any portion of a return air system having a design capacity greater than 15,000 cubic feet per 
minute, smoke detectors shall be installed at each story. Such smoke detectors shall be 
located upstream of the connection between the return air riser and any air ducts or plenums. 

Exception: Smoke detectors are not required in the return air system where all portions 
of the building served by the air distribution system are protected by area smoke 
detectors connected to a fire alarm system in accordance with the 2005 Connecticut 
State Fire Safety Code. The area smoke detection system shall comply with Section 
606.4. 

CHAPTER 7 - COMBUSTION AIR 

(Add) 701.2.1 Group B medical occupancies. Combustion air in Group B medical 
occupancies that provide services or treatment for four or more patients who may 
simultaneously be rendered incapable of taking action for self-preservation under emergency 
conditions shall be provided by outdoor air in accordance with Section 703. 

CHAPTER 10 - BOILERS, WATER HEATERS AND PRESSURE VESSELS 

(Add) 1001.1.1 Boilers and water heaters. Boilers and water heaters shall also be 
governed by the regulations adopted under authority of chapter 540 of the Connecticut General 
Statutes. 

(Del) APPENDIX B - RECOMMENDED PERMIT FEE SCHEDULE. Delete Appendix B without 
substitution. 



; 9 






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iiouNcii? 



2003 International Mechanical Code 



First Printing: February 2003 

Second Printing: May 2003 

Third Printing: April 2004 

Fourth Printing: January 2005 

Fifth Printing: May 2005 
Sixth Printing: December 2005 



ISBN # 1-892395-64-9 (soft-cover edition) 

ISBN # 1-892395-63-0 (loose-leaf edition) 

ISBN # 1-892395-83-5 (e-document) 



COPYRIGHT© 2003 

by 

INTERNATIONAL CODE COUNCIL, INC. 



ALL RIGHTS RESERVED. This 2003 International Mechanical Code® is a copyrighted work owned by the International Code 
Council, Inc. Without advance written permission from the copyright owner, no part of this book may be reproduced, distributed, or 
transmitted in any form or by any means, including, without limitation, electronic, optical or mechanical means (by way of example, 
and not limitation, photocopying, or recording by or in an information storage retrieval system). For information on permission to 
copy material exceeding fair use, please contact: Publications, 4051 West Flossmoor Road, Country Club Hills, IL 60478-5795. 
Phone 1-888-ICC-SAFE (422-7233). 

Trademarks: "International Code Council," the "International Code Council" logo and the "International Mechanical Code" are 
trademarks of the International Code Council, Inc. 



PRINTED IN THE U.S.A. 



PREFACE 

Introduction 

Internationally, code officials recognize the need for a modem, up-to-date mechanical code addressing the design and installa- 
tion of mechanical systems emphasizing performance. The International Mechanical Code®, in this 2003 edition, is designed to 
meet these needs through model code regulations that safeguard the public health and safety in all communities, large and small. 

This comprehensive mechanical code establishes minimum regulations for mechanical systems using prescriptive and perfor- 
mance-related provisions. It is founded on broad-based principles that make possible the use of new materials and new mechanical 
system designs. This 2003 edition is fully compatible with all the International Codes ("I-Codes") pubHshed by the International 
Code Council (ICC), including the International Building Code, ICC Electrical Code, International Energy Conservation Code, In- 
ternational Existing Building Code, International Fire Code, International Fuel Gas Code, ICC Performance Code, International 
Plumbing Code, International Private Sewage Disposal Code, International Property Maintenance Code, International Residen- 
tial Code, International Urban-Wildland Interface Code and International Zoning Code. 

The International Mechanical Code provisions provide many benefits, among which is the model code development process that 
offers an international forum for mechanical professionals to discuss performance and prescriptive code requirements. This forum 
provides an excellent arena to debate proposed revisions. This model code also encourages international consistency in the applica- 
tion of provisions. 

Development 

The first edition of the International Mechanical Code (1996) was the culmination of an effort initiated in 1995 by a develop- 
ment conmiittee appointed by the International Code Council (ICC) and consisting of representatives of the three statutory members 
of the ICC: Building Officials and Code Administrators International, Inc. (BOCA), International Conference of Building Officials 
(ICBO) and Southern Building Code Congress International (SBCCI). The intent was to draft a comprehensive set of regulations for 
mechanical systems consistent with and inclusive of the scope of the existing model codes. Technical content of the latest model 
codes promulgated by BOCA, ICBO and SBCCI was utilized as the basis for the development. This 2003 edition presents the code 
as originally issued, with changes approved through the ICC Code Development Process through 2002. A new edition such as this is 
promulgated every three years. 

With the development and publication of the family of International Codes in 2000, the continued development and maintenance 
of the model codes individually promulgated by BOCA ("BOCA National Codes"), ICBO ("Uniform Codes") and SBCCI ("Stan- 
dard Codes") was discontinued. This 2003 International Mechanical Code, as well as its predecessor-the 2000 edition-is intended 
to be the successor mechanical code to those codes previously developed by BOCA, ICBO and SBCCI. 

The development of a single set of comprehensive and coordinated International Codes was a significant milestone in the devel- 
opment of regulations for the built environment. The timing of this publication mirrors a milestorie in the change in structure of the 
model codes, namely, the consolidation of BOCA, ICBO and SBCCI into the ICC. The activities and services previously provided 
by the individual model code organizations will be the responsibility of the consolidated ICC. 

This code is founded on principles intended to establish provisions consistent with the scope of a mechanical code that ade- 
quately protects public health, safety and welfare; provisions that do not unnecessarily increase construction costs; provisions that 
do not restrict the use of new materials, products or methods of construction; and provisions that do not give preferential treatment to 
particular types or classes of materials, products or methods of construction. 

Adoption 

The International Mechanical Code is available for adoption and use by jurisdictions internationally. Its use within a governmental 
jurisdiction is intended to be accomplished through adoption by reference in accordance with proceedings establishing the jurisdic- 
tion's laws. At the time of adoption, jurisdictions should insert the appropriate information in provisions requiring specific local infor- 
mation, such as the name of the adopting jurisdiction. These locations are shown in bracketed words in small capital letters in the code 
and in the sample ordinance. The sample adoption ordinance on page v addresses several key elenients of a code adoption ordinance, 
including the information required for insertion into the code text. 

Maintenance 

The International Mechanical Code is kept up to date through the review of proposed changes submitted by code enforcing offi- 
cials, industry representatives, design professionals and other interested parties. Proposed changes are carefully considered through 
an open code development process in which all interested and affected parties may participate. 



2003 INTERNATIONAL MECHANICAL CODE® Mi 



The contents of this work are subject to change both through the Code Development Cycles and the governmental body that en- 
acts the code into law. For more information regarding the code development process, contact the Code and Standard Development 
Department of the International Code Council. 

While the development procedure of the International Mechanical Code assures the highest degree of care, ICC and the founding 
members of ICC — BOCA, ICBO, SBCCI — their members and those participating in the development of this code do not accept any U- 
ability resulting from compliance or noncompliance with the provisions because ICC and its founding members do not have the power 
or authority to police or enforce compliance with the contents of this code. Only the governmental body that enacts the code into law 
has such authority. 

Letter Designations in Front of Section Numbers 

In each code development cycle, proposed changes to this code are considered at the Code Development Hearing by the Interna- 
tional Mechanical Code Development Conrnrnttee, whose action constitutes a recommendation to the voting membership for final 
action on the proposed change. Proposed changes to a code section whose number begins with a letter in brackets are considered by a 
different code development committee. For instance, proposed changes to code sections which have the letter [B] in front (for exam- 
ple, [B] 601.2), are considered by the International Building Code Development Committee at the Code Development Hearing. 
Where this designation is applicable to the entire content of a main section of the code, the designation appears at the main section 
number and title and is not repeated at every subsection in that section. 

The content of sections in this code which begin with a letter designation are maintained by another code development committee 
in accordance with the following: [B] = International Building Code Development Committee; [E] = International Energy Conser- 
vation Code Development Committee; [EB] = International Existing Building Code Development Committee; and [F] = Interna- 
tional Fire Code Development Committee. 

Marginal Markings 

Sohd vertical lines in the margins within the body of the code indicate a technical change from the requirements of the 2000 edi- 
tion. Deletion indicators (■►) are provided in the margin where a paragraph or item has been deleted. 



2003 INTERNATIONAL MECHANICAL CODE® 



ORDINANCE 

The International Codes due designed and promulgated to be adopted by reference by ordinance. Jurisdictions wishing to adopt the 
2003 International Mechanical Code as an enforceable regulation governing mechanical systems should ensure that certain factual 
information is included in the adopting ordinance at the time adoption is being considered by the appropriate governmental body. 
The following sample adoption ordinance addresses several key elements of a code adoption ordinance, including the information 
required for insertion into the code text. 

SAMPLE ORDINANCE FOR ADOPTION OF 

THE INTERNATIONAL MECHANICAL CODE 

ORDINANCE NO. 

An ordinance of the [JURISDICTION] adopting the 2003 edition of the International Mechanical Code, regulating and governing the 
design, construction, quality of materials, erection, installation, alteration, repair, location, relocation, replacement, addition to, use 
or maintenance of mechanical systems in the [JURISDICTION]; providing for the issuance of permits and collection of fees therefor; 
repealing Ordinance No. of the [JURISDICTION] and all other ordinances and parts of the ordinances in conflict therewith. 

The [GOVERNING BODY] of the [JURISDICTION] does ordain as follows: 

Section l.That a certain document, three (3) copies of which are on file in the office of the [TITLE OF JURISDICTION'S KEEPER OF 
RECORDS] of [NAME OF JURISDICTION] , being marked and designated as the International Mechanical Code, 2003 edition, includ- 
ing Appendix Chapters [FILL IN THE APPENDIX CHAPTERS BEING ADOPTED] (see International Mechanical Code Section 101 .2.1 , 
2003 edition), as published by the International Code Council, be and is hereby adopted as the Mechanical Code of the [JURISDIC- 
TION], in the State of [STATE NAME] regulating and governing the design, construction, quality of materials, erection, installation, al- 
teration, repair, location, relocation, replacement, addition to, use or maintenance of mechanical systems as herein provided; 
providing for the issuance of permits and collection of fees therefor; and each and all of the regulations, provisions, penalties, condi- 
tions and terms of said Mechanical Code on file in the office of the [JURISDICTION] are hereby referred to, adopted, and made a part 
hereof, as if fully set out in this ordinance, with the additions, insertions, deletions and changes, if any, prescribed in Section 2 of this 
ordinance. 

Section 2.The following sections are hereby revised: 

Section 101.1. Insert: [NAME OF JURISDICTION] 

Section 106.5.2. Insert: [APPROPRIATE SCHEDULE] 

Section 106.5.3. Insert: [PERCENTAGES IN TWO LOCATIONS] i 

Section 108.4. Insert: [OFFENSE, DOLLAR AMOUNT, NUMBER OF DAYS] 

Section 108.5. Insert: [DOLLAR AMOUNT IN TWO LOCATIONS] 

Section 3.That Ordinance No. of [JURISDICTION] entitled [FILL IN HERE THE COMPLETE TITLE OF THE ORDINANCE OR 

ORDINANCES IN EFFECT AT THE PRESENT TIME SO THAT THEY WILL BE REPEALED BY DEFINITE MENTION] and all Other Ordi- 
nances or parts of ordinances in conflict herewith are hereby repealed. 

Section 4.That if any section, subsection, sentence, clause or phrase of this ordinance is, for any reason, held to be unconstitutional, 
such decision shall not affect the validity of the remaining portions of this ordinance. The [GOVERNING BODY] hereby declares that it 
would have passed this ordinance, and each section, subsection, clause or phrase thereof, irrespective of the fact that any one or more 
sections, subsections, sentences, clauses and phrases be declared unconstitutional. 

Section S.That nothing in this ordinance or in the Mechanical Code hereby adopted shall be construed to affect any suit or proceed- 
ing impending in any court, or any rights acquired, or liability incurred, or any cause or causes of action acquired or existing, under 
any act or ordinance hereby repealed as cited in Section 2 of this ordinance; nor shall any just or legal right or remedy of any charac- 
ter be lost, impaired or affected by this ordinance. 

Section 6.That the [JURISDICTION'S KEEPER OF RECORDS] is hereby ordered and directed to cause this ordinance to be published. 
(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 circulation. Posting may also be required.) 

Section T.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. 



2003 INTERNATIONAL MECHANICAL CODE® 



2003 INTERNATIONAL MECHANICAL CODE® 



TABLE OF CONTENTS 



CHAPTER 1 ADMINISTRATION 1 

Section 

101 General 1 

102 Applicability 1 

103 Department of Mechanical Inspection 2 

104 Duties and Powers of the Code Official 2 

105 Approval 2 

106 Permits 3 

107 Inspections and Testing 4 

108 Violations 5 

109 Means of Appeal 6 

CHAPTER 2 DEFINITIONS 9 

Section 

201 General 9 

202 General Definitions 9 

CHAPTER 3 GENERAL REGULATIONS 19 

Section 

301 General 19 

302 Protection of Structure 20 

303 Equipment and Appliance Location 20 

304 Installation 21 

305 Piping Support 22 

306 Access and Service Space 23 

307 Condensate Disposal 24 

308 Clearance Reduction 25 

309 Temperature Control 25 

310 Explosive Control 25 

311 Smoke and Heat Vents 25 

312 Heating and Cooling Load Calculations 25 

CHAPTER 4 VENTILATION 27 

Section 

401 General 27 

402 Natural Ventilation 27 

403 Mechanical Ventilation 28 

404 Enclosed Parking Garages 30 

405 Systems Control 30 

406 Ventilation of Uninhabited Spaces 30 



CHAPTER 5 EXHAUST SYSTEMS 31 

Section 

501 General 31 

502 Required Systems. 31 

503 Motors and Fans 37 

504 Clothes Dryer Exhaust 38 

505 Domestic Kitchen Exhaust Equipment 38 

506 Commercial Kitchen Hood Ventilation 

System Ducts And Exhaust Equipment 39 

507 Commercial Kitchen Hoods 41 

508 Commercial Kitchen Makeup Air 43 

509 Fire Suppression Systems 44 

510 Hazardous Exhaust Systems 44 

511 Dust, Stock and Refuse Conveying Systems 46 

512 Subslab Soil Exhaust Systems 47 

513 Smoke Control Systems 47 

514 Energy Recovery Ventilation Systems 52 

CHAPTER 6 DUCT SYSTEMS 53 

Section 

601 General 53 

602 Plenums 53 

603 Duct Construction and Installation 54 

604 Insulation 55 

605 Air Filters 56 

606 Smoke Detection Systems Control 56 

607 Ducts and Air Transfer Openings 57 

CHAPTER 7 COMBUSTION AIR 61 

Section 

701 General 61 

702 Inside Air 61 

703 Outdoor Air 61 

704 Combined Use of Inside and 

Outdoor Air (Condition 1) 62 

705 Combined Use of Inside and 

Outdoor Air (Condition 2) 62 

706 Forced Combustion Air Supply 62 

707 Direct Connection 62 

708 Combustion Air Ducts 63 

709 Opening Obstructions 63 

710 Opening Location and Protection 63 



2003 INTERNATIONAL MECHANICAL CODE® 



CHAPTER 8 CHIMNEYS AND VENTS 65 

Section 

801 General 65 

802 Vents 66 

803 Connectors 67 

804 Direct- Vent, Integral Vent, Mechanical 

Draft Systems 68 

805 Factory-Built Chimneys 69 

806 Metal Chimneys 69 

CHAPTER 9 SPECIFIC APPLIANCES, 

FIREPLACES AND SOLID FUEL- 
BURNING EQUIPMENT 71 

Section 

901 General 71 

902 Masonry Fireplaces 71 

903 Factory-Built Fireplaces 71 

904 Pellet Fuel-Burning Appliances 71 

905 Fireplace Stoves and Room Heaters 71 

906 Factory-Built Barbecue Appliances 71 

907 Incinerators and Crematories 71 

908 Cooling Towers, Evaporative 

Condensers and Fluid Coolers 71 

909 Vented Wall Furnaces 72 

910 Floor Furnaces 72 

91 1 Duct Furnaces 72 

912 Infrared Radiant Heaters 72 

913 Clothes Dryers 72 

914 Sauna Heaters 73 

915 Engine and Gas Turbine-Powered 

Equipment and Appliances 73 

916 Pool and Spa Heaters 73 

917 Cooking Appliances 73 

918 Forced- Air Warm- Air Furnaces 73 

919 Conversion Burners 74 

920 Unit Heaters 74 

921 Vented Room Heaters 74 

922 Kerosene and Oil-Fired Stoves 74 

923 Small Ceramic Kilns 75 

924 Stationary Fuel Cell Power Plants 75 

925 Masonry Heaters 75 

CHAPTER 10 BOILERS, WATER HEATERS 

AND PRESSURE VESSELS 77 

Section 

1001 General 77 



1002 Water Heaters 77 

1003 Pressure Vessels 77 

1004 Boilers 77 

1005 Boiler Connections 78 

1006 Safety and Pressure Relief Valves 

And Controls 78 

1007 Boiler Low-Water Cutoff 78 

1008 Steam Blowoff Valve 79 

1009 Hot Water Boiler Expansion Tank 79 

1010 Gauges 79 

1011 Tests 79 

CHAPTER 11 REFRIGERATION 81 

Section 

1101 General 81 

1 102 System Requirements 81 

1103 Refrigeration System Classification 82 

1 104 System Application Requirements 82 

1105 Machinery Room, General Requirements 87 

1 106 Machinery Room, Special Requirements 88 

1 107 Refrigerant Piping 88 

1108 Field Test 89 

1 109 Periodic Testing 90 

CHAPTER 12 HYDRONIC PIPING 91 

Section 

1201 General 91 

1202 Material 91 

1203 Joints and Connections 92 

1204 Pipe Insulation 93 

1205 Valves 93 

1206 Piping Installation 93 

1207 Transfer Fluid 94 

1208 Tests 94 

1209 Embedded Piping 94 

CHAPTER 13 FUEL OIL PIPING 

AND STORAGE 95 

Section 

1301 General 95 

1302 Material 95 

1303 Joints and Connections 95 

1304 Piping Support 96 

1305 Fuel Oil System Installation 96 

1306 Oil Gauging 96 

1307 Fuel Oil Valves 97 



VIII 



2003 INTERNATIONAL MECHANICAL CODE® 



1308 Testing : 97 

CHAPTER 14 SOLAR SYSTEMS 99 

Section 

1401 General 99 

1402 Installation 99 

1403 Heat Transfer Fluids 99 

1404 Matereials 100 

CHAPTER 15 REFERENCED STANDARDS 101 

APPENDIX A COMBUSTION AIR OPENINGS AND 
CHIMNEY CONNECTOR 
PASS-THROUGHS 107 

APPENDIX B RECOMMENDED PERMIT 

FEE SCHEDULE Ill 



INDEX 113 



2003 INTERNATIONAL MECHANICAL CODE® ix 



2003 INTERNATIONAL MECHANICAL CODE® 



CHAPTER 1 

ADMINISTRATION 



SECTION 101 
GENERAL 

101.1 Title. These regulations shall be known as the Mechani- 
cal Code of [NAME OF JURISDICTION] , hereinafter referred to as 
"this code." 

101.2 Scope. This code shall regulate the design, installation, 
maintenance, alteration and inspection of mechanical systems 
that are permanently installed and utilized to provide control of 
environmental conditions and related processes within build- 
ings. This code shall also regulate those mechanical systems, 
system components, equipment and appliances specifically ad- 
dressed herein. The installation of fuel gas distribution piping 
and equipment, fuel gas-fired appliances and fuel gas-fired ap- 
pliance venting systems shall be regulated by the International 
Fuel Gas Code. 

Exceptions: 

1 . Detached one- and two-family dwellings and multiple 
single-family dwellings (townhouses) not more than 
three stories high with separate means of egress and 
their accessory structures shall comply with the Inter- 
national Residential Code, 

2. Mechanical systems in existing buildings undergoing 
repair, alterations, or additions, and change of occu- 
pancy shall be permitted to comply with the Interna- 
tional Existing Building Code. 

101.2.1 Appendices. Provisions in the appendices shall not 
apply unless specifically adopted. 

101.3 Intent. The purpose of this code is to provide minimum 
standards to safeguard life or limb, health, property and public 
welfare by regulating and controlling the design, construction, 
installation, quality of materials, location, operation and main- 
tenance or use of mechanical systems. 

101.4 Severability. If a section, subsection, sentence, clause or 
phrase of this code is, for any reason, held to be unconstitu- 
tional, such decision shall not affect the validity of the remain- 
ing portions of this code. 



SECTION 102 
APPLICABILITY 

102.1 General. The provisions of this code shall apply to all 
matters affecting or relating to structures and premises, as set 
forth in Section 101. Where, in a specific case, different sec- 
tions of this code specify different materials, methods of con- 
struction or other requirements, the most restrictive shall 
govern. 

102.2 Existing installations. Except as otherwise provided for 
in this chapter, a provision in this code shall not require the re- 
moval, alteration or abandonment of, nor prevent the continued 
utilization and maintenance of, a mechanical system lawfully 
in existence at the time of the adoption of this code. 



102.3 Maintenance. Mechanical systems, both existing and 
new, and parts thereof shall be maintained in proper operating 
condition in accordance with the original design and in a safe 
and sanitary condition. Devices or safeguards which are re- 
quired by this code shall be maintained in compliance with the 
code edition under which they were installed. The owner or the 
owner's designated agent shall be responsible for maintenance 
of mechanical systems. To determine compliance with this pro- 
vision, the code official shall have the authority to require a me- 
chanical system to be reinspected. 

[EB] 102.4 Additions, alterations or repairs. Additions, al- 
terations, renovations or repairs to a mechanical system shall 
conform to that required for a new mechanical system without 
requiring the existing mechanical system to comply with all of 
the requirements of this code. Additions, alterations or repairs 
shall not cause an existing mechanical system to become un- 
safe, hazardous or overloaded. 

Minor additions, alterations, renovations and repairs to ex- 
isting mechanical systems shall meet the provisions for new 
construction, unless such work is done in the same manner and 
arrangement as was in the existing system, is not hazardous and 
is approved. 

[EB] 102.5 Change in occupancy. It shall be unlawful to make 
a change in the occupancy of any structure which will subject 
the structure to any special provision of this code applicable to 
the new occupancy without approval. The code official shall 
certify that such structure meets the intent of the provisions of 
law governing building construction for the proposed new oc- 
cupancy and that such change of occupancy does not result in 
any hazard to the public health, safety or welfare. 

[EB] 102.6 Historic buildings. The provisions of this code re- 
lating to the construction, alteration, repair, enlargement, resto- 
ration, relocation or moving of buildings or structures shall not 
be mandatory for existing buildings or structures identified and 
classified by the state or local jurisdiction as historic buildings 
when such buildings or structures are judged by the code offi- 
cial to be safe and in the public interest of health, safety and 
welfare regarding any proposed construction, alteration, repair, 
enlargement, restoration, relocation or moving of buildings. 

102.7 Moved buildings. Except as determined by Section 
102.2, mechanical systems that are a part of buildings or struc- 
tures moved into or within the jurisdiction shall comply with 
the provisions of this code for new installations. 

102.8 Referenced codes and standards. The codes and stan- 
dards referenced herein shall be those that are listed in Chapter 
15 and such codes and standards shall be considered as part of 
the requirements of this code to the prescribed extent of each 
such reference. Where differences occur between provisions of 
this code and the referenced standards, the provisions of this 
code shall apply. 

102.9 Requirements not covered by this code. Requirements 
necessary for the strength, stability or proper operation of an 



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ADMINISTRATION 



existing or proposed mechanical system, or for the public 
safety, health and general welfare, not specifically covered by 
this code, shall be determined by the code official. 



SECTION 103 
DEPARTMENT OF MECHANICAL INSPECTION 

103.1 General. The department of mechanical inspection is 
hereby created and the executive official in charge thereof shall 
be known as the code official. 

103.2 Appointment. The code official shall be appointed by 
the chief appointing authority of the jurisdiction; and the code 
official shall not be removed from office except for cause and 
after full opportunity to be heard on specific aiid relevant 
charges by and before the appointing authority. 

103.3 Deputies. In accordance with the prescribed procedures 
of this jurisdiction and with the concurrence of the appointing 
authority, the code official shall have the authority to appoint a 
deputy code official, other related technical officers, inspectors 
and other employees. 

103.4 Liability. The code official, officer or employee charged 
with the enforcement of this code, while acting for the jurisdic- 
tion, shall not thereby be rendered liable personally, and is 
hereby relieved from all personal Uability for any damage ac- 
cruing to persons or property as a result of an act required or 
permitted in the discharge of official duties. 

Any suit instituted against any officer or employee because 
of an act performed by that officer or employee in the lawful 
discharge of duties and under the provisions of this code shall 
be defended by the legal representative of the jurisdiction until 
the final termination of the proceedings. The code official or 
any subordinate shall not be liable for costs in an action, suit or 
proceeding that is instituted in pursuance of the provisions of 
this code; and any officer of the department of mechanical in- 
spection, acting in good faith and without malice, shall be free 
from liability for acts performed under any of its provisions or 
by reason of any act or omission in the performance of official 
duties in connection therewith. 



SECTION 104 
DUTIES AND POWERS OF THE CODE OFFICIAL 

104.1 General. The code official shall enforce the provisions 
of this code and shall act on any question relative to the installa- 
tion, alteration, repair, maintenance or operation of mechanical 
systems, except as otherwise specifically provided for by statu- 
tory requirements or as provided for in Sections 104.2 through 
104.8. 

104.2 Rule-making authority. The code official shall have au- 
thority as necessary in the interest of public health, safety and 
general welfare, to adopt and promulgate rules and regulations; 
to interpret and implement the provisions of this code; to secure 
the intent thereof; and to designate requirements applicable be- 
cause of local climatic or other conditions. Such rules shall not 
have the effect of waiving structural or fire performance re- 
quirements specifically provided for in this code, or of violat- 
ing accepted engineering methods involving public safety. 



104.3 Applications and permits. The code official shall re- 
ceive applications and issue permits for the installation and al- 
teration of mechanical systems, inspect the premises for which 
such permits have been issued and enforce compliance with the 
provisions of this code. 

104.4 Inspections. The code official shall make all of the re- 
quired inspections, or shall accept reports of inspection by ap- 
proved agencies or individuals. AH reports of such inspections 
shall be in writing and be certified by a responsible officer of 
such approved agency or by the responsible individual. The 
code official is authorized to engage such expert opinion as 
deemed necessary to report upon unusual technical issues that 
arise, subject to the approval of the appointing authority. 

104.5 Right of entry. Whenever it is necessary to make an in- 
specfion to enforce the provisions of this code, or whenever the 
code official has reasonable cause to believe that there exists in 
a building or upon any premises any conditions or violations of 
this code which make the building or premises unsafe, insani- 
tary, dangerous or hazardous, the code official shall have the 
authority to enter the building or premises at all reasonable 
times to inspect or to perform the duties imposed upon the code 
official by this code. If such building or premises is occupied, 
the code official shall present credentials to the occupant and 
request entry. If such building or premises is unoccupied, the 
code official shall first make a reasonable effort to locate the 
owner or other person having charge or control of the building 
or premises and request entry. If entry is refused, the code offi- 
cial has recourse to every remedy provided by law to secure en- 
try. 

When the code official has first obtained a proper inspection 
warrant or other remedy provided by law to secure entry, an 
owner or occupant or person having charge, care or control of 
the building or premises shall not fail or neglect, after proper re- 
quest is made as herein provided, to promptly permit entry 
therein by the code official for the purpose of inspection and ex- 
amination pursuant to this code. 

104.6 Identification. The code official shall carry proper iden- 
tification when inspecting structures or premises in the perfor- 
mance of duties under this code. 

104.7 Notices and orders. The code official shall issue all nec- 
essary notices or orders to ensure compliance with this code. 

104.8 Department records. The code official shall keep offi- 
cial records of applications received, permits and certificates 
issued, fees collected, reports of inspecfions, and notices and 
orders issued. Such records shall be retained in the official re- 
cords as long as the building or structure to which such records 
relate remains in existence, unless otherwise provided for by 
other regulations. 



SECTION 105 
APPROVAL 

105.1 Modifications. Whenever there are practical difficulties 
involved in carrying out the provisions of this code, the code of- 
ficial shall have the authority to grant modificafions for individ- 
ual cases, provided the code official shall first find that special 
individual reason makes the strict letter of this code impractical 
and the modification is in compUance with the intent and pur- 



2003 INTERNATIONAL MECHANICAL CODE® 



ADMINISTRATION 



pose of this code and does not lessen health, life and fire safety 
requirements. The details of action granting modifications 
shall be recorded and entered in the files of the mechanical in- 
spection department. 

105.2 Alternative materials, methods, equipment and ap- 
pliances. The provisions of this code are not intended to pre- 
vent the installation of any material or to prohibit any method of 
construction not specifically prescribed by this code, provided 
that any such alternative has been approved. An alternative ma- 
terial or method of construction shall be approved where the 
code official finds that the proposed design is satisfactory and 
complies with the intent of the provisions of this code, and that 
the material, method or work offered is, for the purpose in- 
tended, at least the equivalent of that prescribed in this code in 
quality, strength, effectiveness, fire i-esistance, durability and 
safety. 

105.3 Required testing. Whenever there is insufficient evi- 
dence of compliance with the provisions of this code, or evi- 
dence that a material or method does not conform to the 
requirements of this code, or in order to substantiate claims for 
alternative materials or methods, the code official shall have the 
authority to require tests as evidence of compliance to be made 
at no expense to the jurisdiction. 

105.3.1 Test methods. Test methods shall be as specified in 
this code or by other recognized test standards. In the ab- 
sence of recognized and accepted test methods, the code of- 
ficial shall approve the testing procedures. 

105.3.2 Testing agency. All tests shall be performed by an 
approved agency. 

105.3.3 Test reports. Reports of tests shall be retained by 
the code official for the period required for retention of pub- 
lic records. 

105.4 Material, equipment and appliance reuse. Materials, 
equipment, appliances and devices shall not be reused unless 
such elements have been reconditioned, tested and placed in 
good and proper working condition and approved. 



SECTION 106 
PERMITS 

106.1 When required. An owner, authorized agent or contrac- 
tor who desires to erect, install, enlarge, alter, repair, remove, 
convert or replace a mechanical system, the installation of 
which is regulated by this code, or to cause such work to be 
done, shall first make appUcation to the code official and obtain 
the required permit for the work. 

Exception: Where equipment and appliance replacements 
or repairs must be performed in an emergency situation, the 
permit application shall be submitted within the next work- 
ing business day of the department of mechanical inspec- 
tion. 

106.2 Permits not required. Permits shall not be required for 
the following: 

1. Portable heating appliances; 

2. Portable ventilation appliances and equipment; 

3. Portable cooling units; 



4. Steam, hot water or chilled water piping within any heat- 
ing or cooling equipment or appliances regulated by this 
code; 

5 . The replacement of any minor part that does not alter the 
approval of equipment or an appliance or make such 
equipment or appliance unsafe; 

6. Portable evaporative coolers; and 

7. Self-contained refrigeration systems that contain 10 
pounds (4.5 kg) or less of refrigerant, or that are actuated 
by motors of 1 horsepower (0.75 kW) or less. 

8. Portable fuel cell appliances that are not connected to a 
fixed piping system and are not interconnected to a 
power grid. 

Exemption from the permit requirements of this code shall 
not be deemed to grant authorization for work to be done in vio- 
lation of the provisions of this code or other laws or ordinances 
of this jurisdiction. 

106.3 Application for permit. Each application for a permit, 
with the required fee, shall be filed with the code official on a 
form furnished for that purpose and shall contain a general de- 
scription of the proposed work and its location. The application 
shall be signed by the owner or an authorized agent. The permit 
application shall indicate the proposed occupancy of all parts 
of the building and of that portion of the site or lot, if any, not 
covered by the building or structure and shall contain such 
other information required by the code official. 

106.3.1 Construction documents. Construction docu- 
ments, engineering calculations, diagrams and other data 
shall be submitted in two or more sets with each application 
for a permit. The code official shall require construction 
documents, computations and specifications to be prepared 
and designed by a registered design professional when re- 
quired by state law. Construction documents shall be drawn 
to scale and shall be of sufficient clarity to indicate the loca- 
tion, nature and extent of the work proposed and show in de- 
tail that the work conforms to the provisions of this code. 
Construction documents for buildings more than two stories 
in height shall indicate where penetrations will be made for 
mechanical systems, and the materials and methods for 
maintaining required structural safety, fire-resistance rating 
and fireblocking. 

Exception: The code official shall have the authority to 
waive the submission of construction documents, calcu- 
lations or other data if the nature of the work applied for 
is such that reviewing of construction documents is not 
necessary to determine compliance with this code. 

106.4 Permit issuance. The application, construction docu- 
ments and other data filed by an applicant for a permit shall be 
reviewed by the code official. If the code official finds that the 
proposed work conforms to the requirements of this code and 
all laws and ordinances applicable thereto, and that the fees 
specified in Section 106.5 have been paid, a permit shall be is- 
sued to the applicant. 

106.4.1 Approved construction documents. When the 
code official issues the pernut where construction docu- 
ments are required, the construction documents shall be en- 
dorsed in writing and stamped "APPROVED." Such 



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ADMINISTRATION 



approved construction documents shall not be changed, 
modified or altered without authorization from the code 
official. Work shall be done in accordance with the ap- 
proved construction documents. 

The code official shall have the authority to issue a permit 
for the construction of part of a mechanical system before 
the construction documents for the entire system have been 
submitted or approved, provided adequate information and 
detailed statements have been filed complying with all perti- 
nent requirements of this code. The holder of such permit 
shall proceed at his or her own risk without assurance that 
the permit for the entire mechanical system will be granted. 

106.4.2 Validity. The issuance of a permit or approval of 
construction documents shall not be construed to be a per- 
mit for, or an approval of, any violation of any of the provi- 
sions of this code or of other ordinances of the jurisdiction. 
A permit presuming to give authority to violate or cancel the 
provisions of this code shall be invalid. 

The issuance of a permit based upon construction docu- 
ments and other data shall not prevent the code official from 
thereafter requiring the correction of errors in said construc- 
tion documents and other data or from preventing building 
operations from being carried on thereunder when in viola- 
tion of this code or of other ordinances of this jurisdiction. 

106.4.3 Expiration. Every permit issued by the code offi- 
cial under the provisions of this code shall expire by limita- 
tion and become null and void if the work authorized by 
such permit is not commenced within 180 days from the 
date of such permit, or if the work authorized by such permit 
is suspended or abandoned at any time after the work is 
conmienced for a period of 180 days. Before such work re- 
commences, a new permit shall be first obtained and the fee, 
therefore, shall be one-half the amount required for a new 
permit for such work, provided no changes have been made 
or will be made in the original construction documents for 
such work, and provided further that such suspension or 
abandonment has not exceeded one year. 

106.4.4 Extensions. A permittee holding an unexpired per- 
mit shall have the right to apply for an extension of the time 
within which the permittee will commence work under that 
permit when work is unable to be commenced within the 
time required by this section for good and satisfactory rea- 
sons. The code official shall extend the time for action by the 
permittee for a period not exceeding 180 days if there is rea- 
sonable cause. A permit shall not be extended more than 
once. The fee for an extension shall be one-half the amount 
required for a new permit for such work. 

106.4.5 Suspension or revocation of permit. The code of- 
ficial shall revoke a permit or approval issued under the pro- 
visions of this code in case of any false statement or 
misrepresentation of fact in the application or on the con- 
struction documents upon which the permit or approval was 
based. 

106.4.6 Retention of construction documents. One set of 

construction documents shall be retained by the code offi- 
cial until final approval of the work covered therein. One set 
of approved construction documents shall be returned to the 
applicant, and said set shall be kept on the site of the build- 



ing or job at all times during which the work authorized 
thereby is in progress. 

106.5 Fees. A permit shall not be issued until the fees pre- 
scribed in Section 106.5.2 have been paid, nor shall an amend- 
ment to a permit be released until the additional fee, if any, due 
to an increase of the mechanical system, has been paid. 

106.5.1 Work commencing before permit issuance. Any 

person who commences work on a mechanical system be- 
fore obtaining the necessary permits shall be subject to 100 
percent of the usual permit fee in addition to the required 
permit fees. 

106.5.2 Fee schedule. The fees for mechanical work shall 
be as indicated in the following schedule. 

[JURISDICTION TO INSERT 
APPROPRIATE SCHEDULE] 

106.5.3 Fee refunds. The code official shall authorize the 
refunding of fees as follows. 

1. The full amount of any fee paid hereunder which was 
erroneously paid or collected. 

2. Not more than [SPECIFY PERCENTAGE] percent of the 
permit fee paid when no work has been done under a 
permit issued in accordance with this code. 

3. Not more than [SPECIFY percentage] percent of the 
plan review fee paid when an application for a permit 
for which a plan review fee has been paid is with- 
drawn or canceled before any plan review effort has 
been expended. 

The code official shall not authorize the refunding of any 
fee paid, except upon written application filed by the origi- 
nal permittee not later than 180 days after the date of fee 
payment. 



SECTION 107 
INSPECTIONS AND TESTING 

107.1 Required inspections and testing. The code official, 
upon notification from the permit holder or the permit holder's 
agent, shall make the following inspections and other such in- 
spections as necessary, and shall either release that portion of 
the construction or shall nofify the permit holder or the permit 
holder's agent of violations that must be corrected. The holder 
of the permit shall be responsible for the scheduHng of such in- 
spections. 

1. Underground inspection shall be made after trenches or 
ditches are excavated and bedded, piping installed, and 
before backfill is put in place. When excavated soil con- 
tains rocks, broken concrete, frozen chunks and other 
rubble that would damage or break the piping or cause 
corrosive action, clean backfill shall be on the job site. 

2. Rough-in inspection shall be made after the roof, fram- 
ing, fireblocking and bracing are in place and all ducting 
and other components to be concealed are complete, and 
prior to the installation of wall or ceiling membranes. 

3. Final inspection shall be made upon completion of the 
mechanical system. 



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ADMINISTRATION 



Exception: Ground-source heat pump loop systems tested 
in accordance with Section 1208. 1 . 1 shall be permitted to be 
backfilled prior to inspection. 

The requirements of this section shall not be considered to 
prohibit the operation of any heating equipment or appliances 
installed to replace existing heating equipment or appliances 
serving an occupied portion of a structure provided that a re- 
quest for inspection of such heating equipment or appliances 
has been filed with the department not more than 48 hours after 
such replacement work is completed, and before any portion of 
such equipment or appliances is concealed by any permanent 
portion of the structure. 

107.1.1 Approved inspection agencies. The code official 
shall accept reports of approved agencies, provided that 
such agencies satisfy the requirements as to qualifications 
and reliability. 

107.1.2 Evaluation and folloM^-up inspection services. 

Prior to the approval of a prefabricated construction assem- 
bly having concealed mechanical work and the issuance of a 
mechanical permit, the code official shall require the 
submittal of an evaluation report on each prefabricated con- 
struction assembly, indicating the complete details of the 
mechanical system, including a description of the system 
and its components, the basis upon which the system is be- 
ing evaluated, test results and similar information, and other 
data as necessary for the code official to determine confor- 
mance to this code. 

107.1.2.1 Evaluation service. The code official shall 
designate the evaluation service of an approved agency 
as the evaluation agency, and review such agency's eval- 
uation report for adequacy and conformance to this code. 

107.1.2.2 Follow-up inspection. Except where ready ac- 
cess is provided to mechanical systems, service equip- 
ment and accessories for complete inspection at the site 
without disassembly or dismantling, the code official 
shall conduct the in-plant inspections as frequently as 
necessary to ensure conformance to the approved evalua- 
tion report or shall designate an independent, approved 
inspection agency to conduct such inspections. The in- 
spection agency shall furnish the code official with the 
follow-up inspection manual and a report of inspections 
upon request, and the mechanical system shall have an 
identifying label permanently affixed to the system indi- 
cating that factory inspections have been performed. 

107.1.2.3 Test and inspection records. Required test 
and inspection records shall be available to the code offi- 
cial at all times during the fabrication of the mechanical 
system and the erection of the building; or such records 
as the code official designates shall be filed. 

107.2 Testing. Mechanical systems shall be tested as required 
in this code and in accordance with Sections 107.2.1 through 
107.2.3. Tests shall be made by the permit holder and observed 
by the code official. 

107.2.1 New, altered, extended or repaired systems. New 

mechanical systems and parts of existing systems, which 
have been altered, extended, renovated or repaired, shall be 
tested as prescribed herein to disclose leaks and defects. 



107.2.2 Apparatus, material and labor for tests. Appara- 
tus, material and labor required for testing a mechanical sys- 
tem or part thereof shall be furnished by the permit holder. 

107.2.3 Reinspection and testing. Where any work or in- 
stallation does not pass an initial test or inspection, the nec- 
essary corrections shall be made so as to achieve 
compliance with this code. The work or installation shall 
then be resubmitted to the code official for inspection and 
testing. 

107.3 Approval. After the prescribed tests and inspections in- 
dicate that the work complies in all respects with this code, a 
notice of approval shall be issued by the code official. 

107.4 Temporary connection. The code official shall have the 
authority to authorize the temporary connection of a mechani- 
cal system to the sources of energy for the purpose of testing 
mechanical systems or for use under a temporary certificate of 
occupancy. 



SECTION 108 
VIOLATIONS 

108.1 Unlawful acts. It shall be unlawful for a person, firm or 
corporation to erect, construct, alter, repair, remove, demolish 
or utiHze a mechanical system, or cause same to be done, in 
conflict with or in violation of any of the provisions of this 
code. 

108.2 Notice of violation. The code official shall serve a notice 
of violation or order to the person responsible for the erection, 
installation, alteration, extension, repair, removal or demoh- 
tion of mechanical work in violation of the provisions of this 
code, or in violation of a detail statement or the approved con- 
struction documents thereunder, or in violation of a permit or 
certificate issued under the provisions of this code. Such order 
shall direct the discontinuance of the illegal action or condition 
and the abatement of the violation. 

108.3 Prosecution of violation. If the notice of violation is not 
complied with promptly, the code official shall request the legal 
counsel of the jurisdiction to institute the appropriate proceed- 
ing at law or in equity to restrain, correct or abate such viola- 
tion, or to require the removal or termination of the unlawful 
occupancy of the structure in violation of the provisions of this 
code or of the order or direction made pursuant thereto. 

108.4 Violation penalties. Persons who shall violate a provi- 
sion of this code or shall fail to comply with any of the require- 
ments thereof or who shall erect, install, alter or repair 
mechanical work in violation of the approved construction 
documents or directive of the code official, or of a permit or cer- 
tificate issued under the provisions of this code, shall be guilty 
of a [SPECIFY OFFENSE], punishable by a fine of not more than 
[AMOUNT] dollars or by imprisonment not exceeding [number 
OF DAYS], or both such fine and imprisonment. Each day that a 
violation continues after due notice has been served shall be 
deemed a separate offense. 

108.5 Stop v*^ork orders. Upon notice from the code official 
that mechanical work is being done contrary to the provisions 
of this code or in a dangerous or unsafe manner, such work shall 
immediately cease. Such notice shall be in writing and shall be 
given to the owner of the property, or to the owner's agent, or to 



2003 INTERNATIONAL MECHANICAL CODE® 



ADMINISTRATION 



the person doing the work. The notice shall state the conditions 
under which work is authorized to resume. Where an emer- 
gency exists, the code official shall not be required to give a 
written notice prior to stopping the work. Any person who shall 
continue any work on the system after having been served with 
a stop work order, except such work as that person is directed to 
perform to remove a violation or unsafe condition, shall be lia- 
ble for a fine of not less than [AMOUNT] dollars or more than 
[AMOUNT] dollars. 

108.6 Abatement of violation. The imposition of the penalties 
herein prescribed shall not preclude the legal officer of the ju- 
risdiction from instituting appropriate action to prevent unlaw- 
ful construction or to restrain, correct or abate a violation, or to 
prevent illegal occupancy of a building, structure or premises, 
or to stop an illegal act, conduct, business or utilization of the 
mechanical system on or about any premises. 

108.7 Unsafe mechanical systems. A mechanical system that 
is unsafe, constitutes a fire or health hazard, or is otherwise 
dangerous to human life, as regulated by this code, is hereby 
declared as an unsafe mechanical system. Use of a mechanical 
system regulated by this code constituting a hazard to health, 
safety or welfare by reason of inadequate maintenance, dilapi- 
dation, fire hazard, disaster, damage or abandonment is hereby 
declared an unsafe use. Such unsafe equipment and apphances 
are hereby declared to be a public nuisance and shall be abated 
by repair, rehabilitation, demolition or removal. 

108.7.1 Authority to condemn mechanical systems. 

Whenever the code official determines that any mechanical 
system, or portion thereof, regulated by this code has be- 
come hazardous to life, health, property, or has become in- 
sanitary, the code official shall order in writing that such 
system either be removed or restored to a safe condition. A 
time limit for compliance with such order shall be specified 
in the written notice. A person shall not use or maintain a de- 
fective mechanical system after receiving such notice. 

When such mechanical system is to be disconnected, 
written notice as prescribed in Section 108.2 shall be given. 
In cases of immediate danger to life or property, such dis- 
connection shall be made immediately without such notice. 

108.7.2 Authority to order disconnection of energy 
sources. The code official shall have the authority to order 
disconnection of energy sources supplied to a building, 
structure or mechanical system regulated by this code, when 
it is determined that the mechanical system or any portion 
thereof has become hazardous or unsafe. Written notice of 
such order to disconnect service and the causes therefor 
shall be given within 24 hours to the owner and occupant of 
such building, structure or premises, provided, however, 
that in cases of immediate danger to life or property, such 
disconnection shall be made immediately without such no- 
tice. Where energy sources are provided by a public utility, 
the code official shall immediately notify the serving utility 
in writing of the issuance of such order to disconnect. 

108.7.3 Connection after order to disconnect. A person 
shall not make energy source connections to mechanical 
systems regulated by this code which have been discon- 
nected or ordered to be disconnected by the code official, or 
the use of which has been ordered to be discontinued by the 



code official until the code official authorizes the 
reconnection and use of such mechanical systems. 

When a mechanical system is maintained in violation of 
this code, and in violation of a notice issued pursuant to the 
provisions of this section, the code official shall institute ap- 
propriate action to prevent, restrain, correct or abate the vio- 
lation. 



SECTION 109 
MEANS OF APPEAL 

109.1 Application for appeal. A person shall have the right to 
appeal a decision of the code official to the board of appeals. An 
application for appeal shall be based on a claim that the true in- 
tent of this code or the rules legally adopted thereunder have 
been incorrectly interpreted, the provisions of this code do not 
fully apply, or an equally good or better form of construction is 
proposed. The application shall be filed on a form obtained 
from the code official within 20 days after the notice was 
served. 

109.1.1 Limitation of authority. The board of appeals shall 
have no authority relative to interpretation of the administra- 
tion of this code nor shall such board be empowered to waive 
requirements of this code. 

109.2 Membership of board. The board of appeals shall con- 
sist of five members appointed by the chief appointing author- 
ity as follows: one for five years; one for four years; one for 
three years; one for two years; and one for one year. Thereafter, 
each new member shall serve for five years or until a successor 
has been appointed. 

109.2.1 Qualifications. The board of appeals shall consist 
of five individuals, one from each of the following profes- 
sions or disciplines. 

1 . Registered design professional who is a registered ar- 
chitect; or a builder or superintendent of building con- 
struction with at least ten years' experience, five of 
which shall have been in responsible charge of work. 

2. Registered design professional with structural engi- 
neering or architectural experience. 

3. Registered design professional with mechanical and 
plumbing engineering experience; or a mechanical 
contractor with at least ten years' experience, five of 
which shall have been in responsible charge of work. 

4. Registered design professional with electrical engi- 
neering experience; or an electrical contractor with at 
least ten years' experience, five of which shall have 
been in responsible charge of work. 

5. Registered design professional with fire protection 
engineering experience; or a fire protection contractor 
with at least ten years' experience, five of which shall 
have been in responsible charge of work. 

109.2.2 Alternate members. The chief appointing author- 
ity shall appoint two alternate members who shall be called 
by the board chairman to hear appeals during the absence or 
disqualification of a member. Alternate members shall pos- 
sess the qualifications required for board membership and 



2003 INTERNATIONAL MECHANICAL CODE® 



ADMINISTRATION 



shall be appointed for five years, or until a successor has 
been appointed. 

109.2.3 Chairman. The board shall annually select one of 
its nnembers to serve as chairman. 

109.2.4 Disqualification of member. A member shall not 
hear an appeal in which that member has a personal, profes- 
sional or financial interest. 

109.2.5 Secretary. The chief administrative officer shall 
designate a qualified clerk to serve as secretary to the board. 
The secretary shall file a detailed record of all proceedings 
in the office of the chief administrative officer. 

109.2.6 Compensation of members. Compensation of 
members shall be determined by law. 

109.3 Notice of meeting. The board shall meet upon notice 
from the chairman, within ten days of the filing of an appeal, or 
at stated periodic meetings. 

109.4 Open hearing. All hearings before the board shall be 
open to the public. The appellant, the appellant's representa- 
tive, the code official and any person whose interests are af- 
fected shall be given an opportunity to be heard. 

109.4.1 Procedure. The board shall adopt and make avail- 
able to the public through the secretary procedures under 
which a hearing will be conducted. The procedures shall not 
require compliance with strict rules of evidence, but shall 
mandate that only relevant information be received. 

109.5 Postponed hearing. When five members are not present 
to hear an appeal, either the appellant or the appellant's repre- 
sentative shall have the right to request a postponement of the 
hearing. 

109.6 Board decision. The board shall modify or reverse the 
decision of the code official by a concurring vote of three mem- 
bers. 

109.6.1 Resolution. The decision of the board shall be by 
resolution. Certified copies shall be furnished to the appel- 
lant and to the code official. 

109.6.2 Administration. The code official shall take imme- 
diate action in accordance with the decision of the board. 

109.7 Court review. Any person, whether or not a previous 
party of the appeal, shall have the right to apply to the appropri- 
ate court for a writ of certiorari to correct errors of law. Applica- 
tion for review shall be made in the manner and time required 
by law following the filing of the decision in the office of the 
chief administrative officer. 



2003 INTERNATIONAL MECHANICAL CODE® 



2003 INTERNATIONAL MECHANICAL CODE® 



CHAPTER 2 

DEFINITIONS 



SECTION 201 
GENERAL 

201.1 Scope. Unless otherwise expressly stated, the following 
words and terms shall, for the purposes of this code, have the 
meanings indicated in this chapter. 

201.2 Interchangeability. Words used in the present tense in- 
clude the future; words in the masculine gender include the 
feminine and neuter; the singular number includes the plural 
and the plural, the singular. 

201.3 Terms defined in other codes. Where terms are not de- 
fined in this code and are defined in the International Building 
Code, ICC Electrical Code, International Fire Code, Interna- 
tional Fuel Gas Code or the International Plumbing Code, such 
terms shall have meanings ascribed to them as in those codes. 

201.4 Terms not defined. Where terms are not defined through 
the methods authorized by this section, such terms shall have 
ordinarily accepted meanings such as the context implies. 



SECTION 202 
GENERAL DEFINITIONS 

ABRASIVE MATERIALS. Moderately abrasive particulate 
in high concentrations, and highly abrasive particulate in mod- 
erate and high concentrations, such as alumina, bauxite, iron 
silicate, sand and slag. 

ABSORPTION SYSTEM. A refrigerafing system in which 
refrigerant is pressurized by pumping a chemical solution of re- 
frigerant in absorbent, and then separated by the addition of 
heat in a generator, condensed (to reject heat), expanded, evap- 
orated (to provide refrigeration), and reabsorbed in an absorber 
to repeat the cycle; the system may be single or multiple effect, 
the latter using multiple stages or internally cascaded use of 
heat to improve efficiency. 

ACCESS (TO). That which enables a device, appliance or 
equipment to be reached by ready access or by a means that first 
requires the removal or movement of a panel, door or similar 
obstruction [see also "Ready access (to)"]. 

AIR. All air supplied to mechanical equipment and appliances 
for combustion, ventilation, cooHng, etc. Standard air is air at 
standard temperature and pressure, namely, 70 °F (21 °C) and 
29.92 inches of mercury (101.3 kPa). 

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

AIR-CONDITIONING SYSTEM. A system that consists of 
heat exchangers, blowers, filters, supply, exhaust and return 
ducts, and shall include any apparatus installed in connection 
therewith. 



AIR DISTRIBUTION SYSTEM. Any system of ducts, ple- 
nums and air-handling equipment that circulates air within a 
space or spaces and includes systems made up of one or more 
air-handling units. 

AIR, EXHAUST. Air being removed from any space, appli- 
ance or piece of equipment and conveyed directly to the atmo- 
sphere by means of openings or ducts. 

AIR-HANDLING UNIT. A blower or fan used for the pur- 
pose of distributing supply air to a room, space or area. 

AIR, MAKEUP. Air that is provided to replace air being ex- 
hausted. 

ALTERATION. A change in a mechanical system that in- 
volves an extension, addition or change to the arrangement, 
type or purpose of the original installation. 

APPLIANCE. A device or apparatus that is manufactured and 
designed to utilize energy and for which this code provides spe- 
cific requirements. 

APPLMNCE, EXISTING. Any appliance regulated by this 
code which was legally installed prior to the effective date of 
this code, or for which a permit to install has been issued. 

APPLIANCE TYPE. 

High-heat appliance. Any appliance in which the products 
of combustion at the point of entrance to the flue under nor- 
mal operating conditions have a temperature greater than 
2,000°F(1093°C). 

Low-heat appliance (residential appliance). Any appli- 
ance in which the products of combustion at the point of en- 
trance to the flue under normal operating conditions have a 
temperature of 1,000°F (538 °C) or less. 

Medium-heat appliance. Any appliance in which the prod- 
ucts of combustion at the point of entrance to the flue under 
normal operating conditions have a temperature of more 
than 1,000°F (538°C), but not greater than 2,000°F 
(1093X). 

APPLIANCE, VENTED. An appliance designed and in- 
stalled in such a manner that all of the products of combustion 
are conveyed directiy from the appliance to the outside atmo- 
sphere through an approved chimney or vent system. 

APPROVED. Approved by the code official or other authority 
having jurisdiction. 

APPROVED AGENCY. An established and recognized 
agency that is approved by the code official and regularly 
engaged in conducting tests or furnishing inspection services. 

AUTOMATIC BOILER. Any class of boiler that is equipped 
with the controls and limit devices specified in Chapter 10. 

BATHROOM. A room coiiitaining a bathtub, shower, spa or 
similar bathing fixture. 



2003 INTERNATIONAL MECHANICAL CODE® 



DEFINITIONS 



BOILER. A closed heating appliance intended to supply hot 
water or steam for space heating, processing or power purposes. 
Low-pressure boilers operate at pressures less than or equal to 1 5 
pounds per square inch (psi) (103 kPa) for steam and 160 psi 
(11 03 kPa) for water. High-pressure boilers operate at pressures 
exceeding those pressures. 

BOILER ROOM. A room primarily utiHzed for the installa- 
tion of a boiler. 

BRAZED JOINT. A gas-tight joint obtained by the joining of 
metal parts with metallic mixtures or alloys which melt at a 
temperature above 1,000°F (538°C), but lower than the melt- 
ing temperature of the parts to be joined. 

BRAZING. A metal joining process wherein coalescence is 
produced by the use of a nonferrous filler metal having a melt- 
ing point above 1,000°F (538 ''C), but lower than that of the 
base metal being joined. The filler material is distributed be- 
tween the closely fitted surfaces of the joint by capillary attrac- 
tion. 

BTU. Abbreviation for British thermal unit, which is the quan- 
tity of heat required to raise the temperature of 1 pound (454 g) 
of water 1°F (0.56°C) (1 Btu = 1055 J). 

BUILDING. Any structure occupied or intended for support- 
ing or sheltering any occupancy. 

CHIMNEY. A primarily vertical structure containing one or 
more flues, for the purpose of carrying gaseous products of 
combustion and air from a fuel-burning appliance to the out- 
side atmosphere. 

Factory-built chimney. A listed and labeled chimney com- 
posed of factory-made components, assembled in the field 
in accordance with manufacturer's instructions and the con- 
ditions of the listing. 

Masonry chimney. A field-constructed chimney composed 
of solid masonry units, bricks, stones or concrete. 

Metal chimney. A field-constructed chimney of metal. 

CHIMNEY CONNECTOR. A pipe that connects a 
fuel-burning appliance to a chimney. 

CLEARANCE. The minimum distance through air measured 
between the heat-producing surface of the mechanical appli- 
ance, device or equipment and the surface of the combustible 
material or assembly. 

CLOSED COMBUSTION SOLID-FUEL-BURNING AP- 
PLIANCE. A heat-producing appUance that employs a com- 
bustion chamber that has no openings other than the flue collar, 
fuel charging door and adjustable openings provided to control 
the amount of combustion air that enters the combustion cham- 
ber. 

CLOTHES DRYER. An appliance used to dry wet laundry by 
means of heat. Dryer classifications are as follows: 

Type 1. Factory-built package, multiple production. Pri- 
marily used in family living environment. Usually the 
smallest unit physically and in function output. 

Type 2. Factory-built package, multiple production. Used in 
business with direct intercourse of the function with the 
public. Not designed for use in individual family living en- 
vironment. 



CODE. These regulations, subsequent amendments thereto, or 
any emergency rule or regulation that the administrative au- 
thority having jurisdiction has lawfully adopted. 

CODE OFFICIAL. The officer or other designated authority 
charged with the administration and enforcement of this code, 
or a duly authorized representative. 

COMBUSTIBLE ASSEMBLY. Wall, floor, ceiling or other 
assembly constructed of one or more component materials that 
are not defined as noncombustible. 

COMBUSTIBLE LIQUIDS. Any liquids having a flash point 
at or above 100°F (38 °C), and that are divided into the follow- 
ing classifications: 

Class II. Liquids having flash points at or above 100°F 
(38 X) and below 140°F (60°C). 

Class III A. Liquids having flash points at or above 140°F 
(60°C) and below 200"F (93 X). 

Class IIIB, Liquids having flash points at or above 200°F 

(93 X). 

COMBUSTIBLE MATERIAL. Any material not defined as 
noncombustible. 

COMBUSTION. In the context of this code, refers to the rapid 
oxidation of fuel accompanied by the production of heat or heat 
and light. 

COMBUSTION AIR. Air necessary for complete combustion 
of a fuel, including theoretical air and excess air. 

COMBUSTION CHAMBER. The portion of an appliance 
within which combustion occurs. 

COMBUSTION PRODUCTS. Constituents resulting from 
the combustion of a fuel with the oxygen of the air, including 
the inert gases, but excluding excess air. 

COMMERCIAL COOKING RECIRCULATING SYS- 
TEM. Self-contained system consisting of the exhaust hood, the 
cooking equipment, the filters, and the fire suppression system. 
The system is designed to capture cooking vapors and residues 
generated from commercial cooking equipment. The system re- 
moves contaminants from the exhaust air and recirculates the air 
to the space from which it was withdrawn. 

COMMERCIAL COOKING APPLL\NCES. AppHances 
used in a commercial food service establishment for heating or 
cooking food and which produce grease vapors, steam, fumes, 
smoke or odors that are required to be removed through a local 
exhaust ventilation system. Such appliances include deep fat 
fryers; upright broilers; griddles; broilers; steam-jacketed ket- 
tles; hot-top ranges; under-fired broilers (charbroilers); ovens; 
barbecues; rotisseries; and similar appliances. For the purpose 
of this definition, a food service establishment shall include 
any building or a portion thereof used for the preparation and 
serving of food. 

COMMERCIAL KITCHEN HOODS. 

Backshelf hood. A backshelf hood is also referred to as a 
low-proximity hood, or as a sidewall hood where wall 
mounted. It's front lower lip is low over the appliance(s) and 
is "set back" from the front of the appliance(s). It is always 
closed to the rear of the appliances by a panel where 
free-standing, or by a panel or wall where wall mounted, and 



10 



2003 INTERNATIONAL MECHANICAL CODE® 



DEFINITIONS 



its height above the cooking surface varies. (This style of 
hood can be constructed with partial end panels to increase 
its effectiveness in capturing the effluent generated by the 
cooking operation). 

Double island canopy hood. A double island canopy hood 
is placed over back-to-back appliances or appliance lines. It 
is open on all sides and overhangs both fronts and the sides of 
the appliance(s). It could have a wall panel between the backs 
of the appliances. (The fact that exhaust air is drawn from 
both sides of the double canopy to meet in the center causes 
each side of this hood to emulate a wall canopy hood, and thus 
it functions much the same with or without an actual wall 
panel between the backs of the appliances). 

Eyebrow hood. An eyebrow hood is mounted directly to 
the face of an appUance, such as an oven and dishwasher, 
above the opening(s) or door(s) from which effluent is emit- 
ted, extending past the sides and overhanging the front of the 
opening to capture the effluent. 

Pass-over hood. A pass-over hood is a free-standing form 
of a backshelf hood constructed low enough to pass food 
over the top. 

Single island canopy hood. A single island canopy hood is 
placed over a single appliance or appliance line. It is open 
on all sides and overhangs the front, rear, and sides of the ap- 
pliance(s). A single island canopy is more susceptible to 
cross drafts and requires a greater exhaust air flow than an 
equivalent sized wall-mounted canopy to capture and con- 
tain effluent generated by the cooking operation(s). 

Wall canopy hood. A wall canopy exhaust hood is mounted 
against a wall above a single appliance or line of appli- 
ance(s), or it could be free-standing with a back panel from 
the rear of the appliances to the hood. It overhangs the front 
and sides of the appliance(s) on all open sides. 

(The wall acts as a back panel, forcing the makeup air to 
be drawn across the front of the cooking equipment, thus in- 
creasing the effectiveness of the hood to capture and contain 
effluent generated by the cooking operation(s). 

COMPENSATING HOODS. Compensating hoods are those 
having integral (built-in) makeup air supply. The makeup air 
supply for such hoods is generally supplied from: short-circuit 
flow from inside the hood, air curtain flow from the bottom of 
the front face, and front face discharge from the outside front 
wall of the hood. The compensating makeup airflow can also be 
supplied from the rear or side of the hood, or the rear, front, or 
sides of the cooking equipment. The makeup airflow can be one 
or a combination of methods. 

COMPRESSOR. A specific machine, with or without acces- 
sories, for compressing a gas. 

COMPRESSOR, POSITIVE DISPLACEMENT. A com- 
pressor in which increase in pressure is attained by changing 
the internal volume of the compression chamber. 

COMPRESSOR UNIT. A compressor with its prime mover 
and accessories. 

CONCEALED LOCATION. A location that cannot be ac- 
cessed without damaging permanent parts of the building 
structure or finish surface. Spaces above, below or behind 



readily removable panels or doors shall not be considered as 
concealed. 

CONDENSATE. The liquid that condenses from a gas (in- 
cluding flue gas) caused by a reduction in temperature. 

CONDENSER. A heat exchanger designed to liquefy refriger- 
ant vapor by removal of heat. 

CONDENSING UNIT. A specific refrigerating machine 
combination for a given refrigerant, consisting of one or more 
power-driven compressors, condensers, liquid receivers (when 
required), and the regularly furnished accessories. 

CONDITIONED SPACE. An area, room or space being 
heated or cooled by any equipment or appliance. 

CONFINED SPACES. A space having a volume less than 50 
cubic feet per 1,000 British thermal units per hour (Btu/h) (4.8 
m^/kW) of the aggregate input rating of all appliances installed 
in that space. 

CONSTRUCTION DOCUMENTS. All of the written, 
graphic and pictorial documents prepared or assembled for de- 
scribing the design, location and physical characteristics of the 
elements of the project necessary for obtaining a building per- 
mit. The construction drawings shall be drawn to an appropri- 
ate scale. 

CONTROL. A manual or automatic device designed to regu- 
late the gas, air, water or electrical supply to, or operation of, a 
mechanical system. 

CONVERSION BURNER. A burner designed to supply gas- 
eous fuel to an appliance originally designed to utilize another 
fuel. 

COOKING APPLIANCE. See "Commercial cooking appH- 
ances." 

DAMPER. A manually or automatically controlled device to 
regulate draft or the rate of flow of air or combustion gases. 

Volume damper. A device that, when installed, will restrict, 
retard or direct the flow of air in a duct, or the products of 
combustion in a heat-producing appliance, its vent connec- 
tor, vent or chimney therefrom. 

DESIGN FLOOD ELEVATION. The elevation of the "de- 
sign flood," including wave height, relative to the datum speci- 
fied on the community's legally designated flood hazard area 
map. 

DESIGN WORKING PRESSURE. The maximum allowable 
working pressure for which a specific part of a system is de- 
signed. I 

DIRECT REFRIGERATION SYSTEM. A system in which 
the evaporator or condenser of the refrigerating system is in di- 
rect contact with the air or other substances to be cooled or 
heated. 

DIRECT- VENT APPLIANCES. Appliances that are con- 
structed and installed so that all air for combustion is derived 
from the outside atmosphei'e and all flue gases are discharged 
to the outside atmosphere. 

DRAFT. The pressure difference existing between the appli- 
ance or any component part and the atmosphere, that causes a 



2003 INTERNATIONAL MECHANICAL CODE® 



11 



DEFINITIONS 



continuous flow of air and products of combustion through the 
gas passages of the appliance to the atmosphere. 

Induced draft. The pressure difference created by the ac- 
tion of a fan, blower or ejector, that is located between the 
appliance and the chimney or vent termination. 

Natural draft. The pressure difference created by a vent or 
chimney because of its height, and the temperature differ- 
ence between the flue gases and the atmosphere. 

DRIP. The container placed at a low point in a system of piping 
to collect condensate and from which the condensate is remov- 
able. 

DRY CLEANING SYSTEMS. Dry cleaning plants or sys- 
tems are classified as follows: 

Type I. Those systems using Class I flammable liquid sol- 
vents having a flash point below lOO^F (SS^'C). 

Type II. Those systems using Class II combustible liquid 
solvents having a flash point at or above lOO^F (38°C) and 
below 140T(60°C). 

Type III. Those systems using Class III combustible liquid 
solvents having a flash point at or above 140 ''F (60°C). 

Types IV and V. Those systems using Class IV nonflamma- 
ble Hquid solvents. 

DUCT. A tube or conduit utilized for conveying air. The air 
passages of self-contained systems are not to be construed as 
air ducts. 

DUCT FURNACE. A warm-air furnace normally installed in 
an air distribution duct to supply warm air for heating. This def- 
inition shall apply only to a warm-air heating appliance that, for 
air circulation, depends on a blower not furnished as part of the 
furnace. 

DUCT SYSTEM. A continuous passageway for the transmis- 
sion of air that, in addition to ducts, includes duct fittings, damp- 
ers, plenums, fans and accessory air-handhng equipment and 
appliances. 

DWELLING. A building or portion thereof that contains not 
more than two dwelling units. 

DWELLING UNIT. A single unit providing complete, inde- 
pendent living facihties for one or more persons, including per- 
manent provisions for Uving, sleeping, eating, cooking and 
sanitation. 

ELECTRIC HEATING APPLIANCE. An appliance that 
produces heat energy to create a warm environment by the ap- 
plication of electric power to resistance elements, refrigerant 
compressors or dissimilar material junctions. 

ENERGY RECOVERY VENTILATION SYSTEM. Sys- 
tems that employ air-to-air heat exchangers to recover energy 
from or reject energy to exhaust air for the purpose of 
pre-heating, pre-cooling, humidifying or dehumidifying out- 
door ventilafion air prior to supplying such air to a space, either 
directly or as part of an H VAC system. 

EQUIPMENT. All piping, ducts, vents, control devices and 
other components of systems other than appliances which are 
permanently installed and integrated to provide control of envi- 



ronmental conditions for buildings. This definition shall also 
include other systems specifically regulated in this code. 

EQUIPMENT, EXISTING . Any equipment regulated by this 
code which was legally installed prior to the effective date of 
this code, or for which a permit to install has been issued. 

EVAPORATIVE COOLER. A device used for reducing the 
sensible heat of air for cooling by the process of evaporation of 
water into an airstream. 

EVAPORATIVE COOLING SYSTEM. The equipment and 
appliances intended or installed for the purpose of environmen- 
tal cooling by an evaporative cooler from which the conditioned 
air is distributed through ducts or plenums to the conditioned 
area. 

EVAPORATOR. That part of the system in which liquid re- 
frigerant is vaporized to produce refrigeration. 

EXCESS AIR. The amount of air provided in addition to theo- 
retical air to achieve complete combustion of a fuel, thereby 
preventing the formation of dangerous products of combustion. 

EXHAUST SYSTEM. An assembly of connected ducts, ple- 
nums, fittings, registers, grilles and hqods through which air is 
conducted from the space or spaces and exhausted to the out- 
side atmosphere. 

EXTRA-HEAVY-DUTY COOKING APPLL\NCE. Ex- 
tra-heavy-duty cooking appliances include appliances utilizing 
solid fuel such as wood, charcoal, briquettes, and mesquite as 
the primary source of heat for cooking. 

FIREPLACE. An assembly consisting of a hearth and fire 
chamber of noncombustible material and provided with a 
chimney, for use with solid fuels. 

Factory-built fireplace. A listed and labeled fireplace and 
chimney system composed of factory-made components, and 
assembled in the field in accordance with manufacturer's in- 
structions and the conditions of the listing. 

Masonry fireplace. A field-constructed fireplace com- 
posed of solid masonry units, bricks, stones or concrete. 

FIREPLACE STOVE. A free-standing chimney-connected 
solid-fuel-buming heater, designed to be operated with the fire 
chamber doors in either the open or closed position. 

FLAME SAFEGUARD. A device that will automatically shut 
off the fuel supply to a main burner or group of burners when 
the means of ignition of such burners becomes inoperative, and 
when flame failure occurs on the burner or group of burners. 

FLAME SPREAD INDEX. The numerical value assigned to 
a material tested in accordance with ASTM E 84. 

FLAMMABILITY CLASSIFICATION. Refrigerants shall 
be assigned to one of the three classes — 1, 2 or 3 — in accor- 
dance with ASHRAE 34. For Classes 2 and 3, the heat of com- 
bustion shall be calculated assuming that combustion products 
are in the gas phase and in their most stable state. 

Class 1. Refrigerants that do not show flame propagation 
when tested in air at 14.7 psia (101 kPa) and 70°F (21 °C). 

Class 2. Refrigerants having a lower flammability limit 
(LFL) of more than 0.00625 pound per cubic foot (0.10 



12 



2003 INTERNATIONAL MECHANICAL CODE® 



DEFINITIONS 



kg/m^) at 70°F (21 °C) and 14.7 psia (101 kPa) and a heat of 
combustion of less than 8,174 Btu/lb (19 000 kJ/kg). 

Class 3. Refrigerants that are highly flammable, having a 
LFL of less than or equal to 0.00625 pound per cubic foot 
(0.10 kg/m^) at 70°F (2rC) and 14.7 psia (101 kPa) or a 
heat of combustion greater than or equal to 8,174 Btu/lb 
(19 000kJ/kg). 

FLAMMABLE LIQUIDS. Any liquid that has a flash point 
below 100°F (38 °C), and has a vapor pressure not exceeding 
40 psia (276 kPa) at 100°F (38 °C). Flammable liquids shall be 
known as Class I liquids and shall be divided into the following 
classifications: 

Class lA. Liquids having a flash point below 73 ''F (23 °C) 
and a boiling point below 100°F (38 °C). 

Class IB. Liquids having a flash point below 73 ^F (23 °C) 
and a boiling point at or above lOO^F (38 °C). 

Class IC. Liquids having a flash point at or above 73 °F 
(23°C) and below 100°F (38X). 

FLAMMABLE VAPOR OR FUMES. Mixtures of gases in 
air at concentrations equal to or greater than the LFL and less 
than or equal to the upper flammabihty limit (UFL). 

FLASH POINT. The minimum temperature corrected to a pres- 
sure of 14.7 psia (101 kPa) at which the appHcation of a test 
flame causes the vapors of a portion of the sample to ignite under 
the conditions specified by the test procedures and apparatus. 
The flash point of a liquid shall be determined in accordance 
with ASTM D 56, ASTM D 93 or ASTM D 3278. 

FLOOR AREA, NET. The actual occupied area, not including 
unoccupied accessory areas or thicknesses of walls. 

FLOOR FURNACE. A completely self-contained furnace 
suspended from the floor of the space being heated, taking air 
for combustion from outside such space and with means for ob- 
serving flames and lighting the appliance from such space. 

FLUE. A passageway within a chimney or vent through which 
gaseous combustion products pass. 

FLUE CONNECTION (BREECHING). A passage for con- 
ducting the products of combustion from a fuel-fired appliance 
to the vent or chimney (see also "Chimney connector" and 
"Vent connector"). 

FLUE GASES. Products of combustion and excess air. 

FLUE LINER (LINING). A system or material used to form 
the inside surface of a flue in a chimney or vent, for the purpose 
of protecting the surrounding structure from the effects of com- 
bustion products and conveying combustion products without 
leakage to the atmosphere. 

FUEL GAS. A natural gas, manufactured gas, liquefied petro- 
leum gas or a mixture of these. 

FUEL OIL. Kerosene or any hydrocarbon oil having a flash 
point not less than 100°F (38 °C). 

FUEL-OIL PIPING SYSTEM. A closed piping system that 
connects a combustible liquid from a source of supply to a 
fuel-oil-buming appliance. 



FURNACE. A completely self-contained heating unit that is 
designed to supply heated air to spaces remote from or adjacent 
to the appliance location. 

FURNACE ROOM. A room primarily utilized for the instal- 
lation of fuel-burning, space-heating and water-heating appli- 
ances other than boilers (see also "Boiler room"). 

FUSIBLE PLUG. A device arranged to relieve pressure by 
operation of a fusible member at a predetermined temperature. 

GROUND SOURCE HEAT PUMP LOOP SYSTEM. Pip- 
ing buried in horizontal or vertical excavations or placed in a 
body of water for the purpose of transporting heat transfer liq- 
uid to and from a heat pump. Included in this definition are 
closed loop systems in which the liquid is recirculated and open 
loop systems in which the liquid is drawn from a well or other 
source. 

HAZARDOUS LOCATION. Any location considered to be a 
fire hazard for flammable vapors, dust, combustible fibers or 
other highly combustible substances. The location is not 
necessarily categorized in the International Building Code as a 
high-hazard use group classification. 

HEAT EXCHANGER. A device that transfers heat from one 
medium to another. 

HEAT PUMP. A refrigeration system that extracts heat from 
one substance and transfers it to another portion of the same 
substance or to a second substance at a higher temperature for a 
beneficial purpose. 

HEAT TRANSFER LIQUID. The operating or thermal stor- 
age liquid in a mechanical system, including water or other liq- 
uid base, and additives at the concentration present under 
operating conditions used to move heat from one location to an- 
other. Refrigerants are not included as heat transfer liquids. 

HEAVY-DUTY COOKING APPLIANCE. Heavy duty 
cooking appliances include electric under-fired broilers, elec- 
tric chain (conveyor) broilers, gas under-fired broilers, gas 
chain (conveyor) broilers, gas open-burner ranges (with or 
without oven), electric and gas wok ranges, and electric and 
gas over-fired (upright) broilers and salamanders. 

HIGH-PROBABILITY SYSTEMS. A refrigeration system 
in which the basic design or the location of components is such 
that a leakage of refrigerant from a failed connection, seal or 
component will enter an occupancy classified area, other than 
the machinery room. 

HIGH-SIDE PRESSURE. The parts of a refrigerating system 
subject to condenser pressure. 

HOOD. An air-intake device used to capture by entrapment, 
impingement, adhesion or similar means, grease and similar 
contaminants before they enter a duct system. 

Type I. A kitchen hood for collecting and removing grease 
vapors and smoke. 

Type II. A general kitchen hood for collecting and remov- 
ing steam, vapor, heat and odors. 

HYDROGEN GENERATING APPLIANCE. A self-con- 
tained package or factory-matched packages of integrated sys- 
tems for generating gaseous hydrogen. Hydrogen generating 



2003 INTERNATIONAL MECHANICAL CODE® 



13 



DEFINITIONS 



■ appliances utilize electrolysis, reformation, chemical, or other 
processes to generate hydrogen. 

IGNITION SOURCE. A flame, spark or hot surface capable 
of igniting flanmiable vapors or fumes. Such sources include 
appliance burners, burner ignitors and electrical switching de- 
vices. 

IMMEDIATELY DANGEROUS TO LIFE OR HEALTH 
(IDLH). The concentration of airborne contaminants that 
poses a threat of death, immediate or delayed permanent ad- 
verse health effects, or effects that could prevent escape from 
such an environment. This contaminant concentration level is 
estabhshed by the National Institute of Occupational Safety 
and Health (NIOSH) based on both toxicity and flanunability. 
It is generally expressed in parts per million by volume (ppm 
v/v) or milUgrams per cubic meter (mg/m^). 

INDIRECT REFRIGERATION SYSTEM. A system in 
which a secondary coolant cooled or heated by the refrigerating 
system is circulated to the air or other substance to be cooled or 
heated. Indirect systems are distinguished by the method of 
application shown below: 

Closed system. A system in which a secondary fluid is ei- 
ther cooled or heated by the refrigerating system and then 
circulated within a closed circuit in indirect contact with the 
air or other substance to be cooled or heated. 

Double-indirect open-spray system. A system in which 
the secondary substance for an indirect open-spray system 
is heated or cooled by an intermediate coolant circulated 
from a second enclosure. 

Open-spray system. A system in which a secondary cool- 
ant is cooled or heated by the refrigerating system and then 
circulated in direct contact with the air or other substance to 
be cooled or heated. 

Vented closed system. A system in which a secondary cool- 
ant is cooled or heated by the refrigerating system and then 
passed through a closed circuit in the air or other substance 
to be cooled or heated, except that the evaporator or con- 
denser is placed in an open or appropriately vented tank. 

JOINT, FLANGED. A joint made by bolting together a pair of 
flanged ends. 

JOINT, FLARED. A metal-to-metal compression joint in 
which a conical spread is made on the end of a tube that is com- 
pressed by a flare nut against a mating flare. 

JOINT, MECHANICAL. A general form of gas-tight joints 
obtained by the joining of metal parts through a posi- 
tive-holding mechanical construction, such as flanged joint, 
screwed joint or flared joint. 

JOINT, PLASTIC ADHESIVE. A joint made in thermoset 
plastic piping by the use of an adhesive substance which forms 
a continuous bond between the mating surfaces without dis- 
solving either one of them. 

JOINT, PLASTIC HEAT FUSION. A joint made in thermo- 
plastic piping by heating the parts sufficiently to permit fusion 
of the materials when the parts are pressed together. 

JOINT, PLASTIC SOLVENT CEMENT. A joint made in 
thermoplastic piping by the use of a solvent or solvent cement 
which forms a continuous bond between the mating surfaces. 



JOINT, SOLDERED. A gas-tight joint obtained by the join- 
ing of metal parts with metaUic mixtures of alloys which melt at 
temperatures between 400°F (204°C) and 1,000°F (538°C). 

JOINT, WELDED. A gas-tight joint obtained by the joining 
of metal parts in molten state. 

LABELED. Devices, equipment, appliances or materials to 
which have been affixed a label, seal, symbol or other identify- 
ing mark of a nationally recognized testing laboratory, inspec- 
tion agency or other organization concerned with product 
evaluation that maintains periodic inspection of the production 
of the above-labeled items and by whose label the manufac- 
turer attests to compliance with applicable nationally 
recognized standards. 

LIGHT-DUTY COOKING APPLIANCE. Light-duty cook 
ing appliances include gas and electric ovens (including stan- 
dard, bake, roasting, revolving, retherm, convection, 
combination convection/steamer, conveyor, deck or deck-style 
pizza, and pastry), electric and gas steam-jacketed kettles, elec- 
tric and gas compartment steamers (both pressure and atmo- 
spheric) and electric and gas cheesemelters. 

LIMIT CONTROL. A device responsive to changes in pres- 
sure, temperature or level for turning on, shutting off or throt- 
tling the gas supply to an appliance. 

LIMITED CHARGE SYSTEM. A system in which, with the 
compressor idle, the design pressure will not be exceeded when 
the refrigerant charge has completely evaporated. 

LISTED. Equipment, appliances or materials included in a Hst 
published by a nationally recognized testing laboratory, inspec- 
tion agency or other organization concerned with product evalu- 
ation that maintains periodic inspection of production of listed 
equipment, appliances or materials, and whose listing states ei- 
ther that the equipment, appliances or material meets nationally 
recognized standards or has been tested and found suitable for 
use in a specified manner. Not all testing laboratories, inspection 
agencies and other organizations concerned with product evalu- 
ation use the same means for identifying listed equipment, appli- 
ances or materials. Some do not recognize equipment, 
appliances or materials as Usted unless they are also labeled. The 
authority having jurisdiction shall utihze the system employed 
by the listing organization to identify a listed product. 

LIVING SPACE. Space within a dwelling unit utilized for liv- 
ing, sleeping, eating, cooking, bathing, washing and sanitation 
purposes. 

LOWER EXPLOSIVE LIMIT (LEL). See "LFL." 

LOWER FLAMMABLE LIMIT (LFL). The minimum con- 
centration of refrigerant that is capable of propagating a flame 
through a homogeneous mixture of refrigerant and air. 

LOWPRESSURE HOT- WATER-HEATING BOILER. A 

boiler furnishing hot water at pressures not exceeding 160 psi 
(1103 kPa) and at temperatures not exceeding 250°F (121 °C). 

LOW-PRESSURE STEAM-HEATING BOILER. A boiler 
furnishing steam at pressures not exceeding 15 psi (103 kPa). 

LOW-PROBABILITY SYSTEMS. A refrigeration system in 
which the basic design or the location of components is such 
that a leakage of refrigerant from a failed connection, seal or 



14 



2003 INTERNATIONAL MECHANICAL CODE® 



DEFINITIONS 



component will not enter an occupancy-classified area, other 
than the machinery room. 

LOW-SIDE PRESSURE. The parts of a refrigerating system 
subject to evaporator pressure. 

MACHINERY ROOM. A room meeting prescribed safety re- 
quirements and in which refrigeration systems or components 
thereof are located (see Sections 1 105 and 1 106). 

MECHANICAL DRAFT SYSTEM. A venting system de- 
signed to remove flue or vent gases by n^echanical means, that 
consists of an induced-draft portion under nonpositive static 
pressure or a forced-draft portion under positive static pressure. 

Forced-draft venting system. A portion of a venting sys- 
tem using a fan or other mechanical means to cause the re- 
moval of flue or vent gases under positive static pressure. 

Induced-draft venting system. A portion of a venting sys- 
tem using a fan or other mechanical means to cause the re- 
moval of flue or vent gases under nonpositive static vent 
pressure. 

Power venting system. A portion of a venting system using 
a fan or other mechanical means to cause the removal of flue 
or vent gases under positive static vent pressure. 

MECHANICAL EQUIPMENT/APPLIANCE ROOM. A 

room or space in which nonfuel-fired mechanical equipment 
and appliances are located. 

MECHANICAL EXHAUST SYSTEM. A system for re- 
moving air from a room or space by mechanical means. 

MECHANICAL JOINT. A connection between pipes, fittings, 
or pipes and fittings, which is neither screwed, caulked, 
threaded, soldered, solvent cemented, brazed nor welded. Also, 
a joint in which compression is applied along the centerline of 
the pieces being joined. Some joints are part of a coupling, fitting 
or adapter. 

MECHANICAL SYSTEM. A system specifically addressed 
and regulated in this code and composed of components, de- 
vices, appliances and equipment. 

MEDIUM-DUTY COOKING APPLIANCE. Medium-duty 
cooking appliances include electric discrete element ranges 
(with or without oven), electric and gas hot-top ranges, electric 
and gas griddles, electric and gas double-sided griddles, electric 
and gas fryers (including open deep fat fryers, donut fryers, ket- 
tle fryers, and pressure fryers), electric and gas pasta cookers, 
electric and gas conveyor pizza ovens, electric and gas tilting 
skillets (braising pans) and electric and gas rotisseries. 

MODULAR BOILER. A steam or hot-water-heating assem- 
bly consisting of a group of individual boilers called modules 
intended to be installed as a unit with no intervening stop 
valves. Modules are under one jacket or are individually jack- 
eted. The individual modules shall be limited to a maximum in- 
put rating of 400,000 Btu/h (117 228 W) gas, 3 gallons per hour 
(gph) (11.4 L/h) oil, or 1 15 kW (electric). 

NATURAL DRAFT SYSTEM. A venting system designed to 
remove flue or vent gases under nonpositive static vent pressure 
entirely by natural draft. 



NATURAL VENTILATION. The movement of air into and 
out of a space through intentionally provided openings, such as 
windows and doors, or through nonpowered ventilators. 

NONABRASrVE/ABRASIVE MATERIALS. Nonabrasive 
particulate in high concentrations, moderately abrasive partic- 
ulate in low and moderate concentrations, and highly abrasive 
particulate in low concentrations, such as alfalfa, asphalt, plas- 
ter, gypsum and salt. 

NONCOMBUSTIBLE MATERIALS. Materials that, when 
tested in accordance with ASTM E 136, have at least three of 
four specimens tested meetijig all of the following criteria: 

1. The recorded temperature of the surface and interior 
thermocouples shall not at any time during the test rise 
more than 54 °F (30°C) above the furnace temperature at 
the beginning of the test. 

2. There shall not be flaming from the specimen after the 
first 30 seconds. 

3. If the weight loss of the specimen during testing exceeds 
50 percent, the recorded temperature of the surface and 
interior thermocouples shall not at any time during the 
test rise above the furnace air temperature at the begin- 
ning of the test, and there shall not be flaming of the spec- 
imen. 

OCCUPANCY. The purpose for which a building, or portion 
thereof, is utiUzed or occupied. 

OFFSET (VENT). A combination of approved bends that 
make two changes in direction bringing one section of the vent 
out of line but into a line parallel with the other section. 

OUTDOOR AIR. Air taken from the outdoors, and therefore 
not previously circulated through the system. 

OUTDOOR OPENING. A door, window, louver or skylight 
openable to the outside atmosphere. 

OUTLET. A threaded connection or bolted flange in a piping 
system to which a gas-burning appliance is attached. 

PANEL HEATING. A method of radiant space heating in 
which heat is supplied by large heated areas of room surfaces. 
The heating element usually consists of warm water piping, 
warm air ducts, or electrical resistance elements embedded in 
or located behind ceiling, wall or floor surfaces. 

PELLET FUEL-BURNING APPLL\NCE. A closed-com- 
bustion, vented appliance equipped with a fuel-feed mecha- 
nism for burning processed pellets of solid fuel of a specified 
size and composition. 

PIPING. Where used in this code, "piping" refers to either 
pipe or tubing, or both. 

Pipe. A rigid conduit of iron, steel, copper, brass or plastic. 

lYibing. Semirigid conduit of copper, aluminum, plastic or 
steel. 

PLASTIC, THERMOPLASTIC. A plastic that is capable of 
being repeatedly softened by increase of temperature and 
hardened by decrease of temperature. 

PLASTIC, THERMOSETTING. A plastic that is capable of 
being changed into a substantially infusible or insoluble prod- 
uct when cured under application of heat or chemical means. 



2003 INTERNATIONAL MECHANICAL CODE® 



15 



DEFINITIONS 



PLENUM. An enclosed portion of the building structure, other 
than an occupiable space being conditioned, that is designed to 
allow air movement, and thereby serve as part of an air distribu- 
tion system. 

PORTABLE FUEL CELL APPLL\NCE. A fuel cell gener- 
ator of electricity, which is not fixed in place. A portable fuel 
cell appliance utilizes a cord and plug connection to a 
grid-isolated load and has an integral fuel supply. 

POWER BOILER. See "Boiler." 

PREMISES. A lot, plot or parcel of land, including any struc- 
ture thereon. 

PRESSURE, FIELD TEST. A test performed in the field to 
prove system tightness. 

PRESSURE-LIMITING DEVICE. A pressure-responsive 
mechanism designed to stop automatically the operation of the 
pressure-imposing element at a predetermined pressure. 

PRESSURE RELIEF DEVICE. A pressure-actuated valve 
or rupture member designed to relieve excessive pressure auto- 
matically. 

PRESSURE RELIEF VALVE. A pressure-actuated valve 
held closed by a spring or other means and designed to relieve 
pressure automatically in excess of the device's setting. 

PRESSURE VESSELS. Closed containers, tanks or vessels 
that are designed to contain liquids or gases, or both, under 
pressure. 

PRESSURE VESSELS— REFRIGERANT. Any refriger- 
ant-containing receptacle in a refrigerating system. This does 
not include evaporators where each separate section does not ex- 
ceed 0.5 cubic foot (0.014 m^) of refrigerant-containing volume, 
regardless of the maximum inside dimensions, evaporator coils, 
controls, headers, pumps and piping. 

PROTECTIVE ASSEMBLY (REDUCED CLEAR- 
ANCE). Any noncombustible assembly that is labeled or con- 
structed in accordance with Table 308.6 and is placed between 
combustible materials or assemblies and mechanical appli- 
ances, devices or equipment, for the purpose of reducing re- 
quired airspace clearances. Protective assembhes attached 
directly to a combustible assembly shall not be considered as 
part of that combustible assembly. 

PURGE. To clear of air, water or other foreign substances. 

QUICK-OPENING VALVE. A valve that opens completely 
by fast action, either manually or automatically controlled. A 
valve requiring one-quarter round turn or less is considered to 
be quick opening. 

RADIANT HEATER. A heater designed to transfer heat pri- 
marily by direct radiation. 

READY ACCESS (TO). That which enables a device, appli- 
ance or equipment to be directly reached, without requiring the 
removal or movement of any panel, door or similar obstruction 
[see "Access (to)"]. 

RECEIVER, LIQUID. A vessel permanently connected to a 
refrigeration system by inlet and outlet pipes for storage of liq- 
uid refrigerant. 



RECIRCULATED AIR. Air removed from a conditioned 
space and intended for reuse as supply air. 

RECLAIMED REFRIGERANTS. Refrigerants reprocessed 
to the same specifications as for new refrigerants by means in- 
cluding distillation. Such refrigerants have been chemically an- 
alyzed to verify that the specifications have been met. 
Reclaiming usually implies the use of processes or procedures 
that are available only at a reprocessing or manufacturing facil- 
ity. 

RECOVERED REFRIGERANTS. Refrigerants removed 
from a system in any condition without necessarily testing or 
processing them. 

RECYCLED REFRIGERANTS. Refrigerants from which 
contaminants have been reduced by oil separation, removal of 
noncondensable gases, and single or multiple passes through 
devices that reduce moisture, acidity and particulate matter, 
such as replaceable core filter driers. These procedures usually 
are performed at the field job site or in a local service shop. 

REFRIGERANT. A substance utihzed to produce refrigera- 
tion by its expansion or vaporization. 

REFRIGERANT SAFETY CLASSIFICATIONS. Group- 
ings that indicate the toxicity and flammabihty classes in 
accordance with Section 1103.1. The classification group is 
made up of a letter ( A or B) that indicates the toxicity class, fol- 
lowed by a number (1, 2 or 3) that indicates the flammability 
class. Refrigerant blends are similarly classified, based on the 
compositions at their worst cases of fractionation, as separately 
determined for toxicity and flammability. In some cases, the 
worst case of fractionation is the original formulation. 

Flammability. Class 1 indicates refrigerants that do not show 
flame propagation in air when tested by prescribed methods 
at specified conditions. Classes 2 and 3 signify refrigerants 
with "lower flammability" and "higher flammabihty," re- 
spectively; the distinction depends on both the LFL and heat 
of combustion. 

Toxicity. Classes A and B signify refrigerants with "lower 
toxicity" and "higher toxicity," respectively, based on pre- 
scribed measures of chronic (long-term, repeated expo- 
sures) toxicity. 

REFRIGERATED ROOM OR SPACE. A room or space in 
which an evaporator or brine coil is located for the purpose of re- 
ducing or controlling the temperature within the room or space to 
below 68'^F(20°C). 

REFRIGERATING SYSTEM. A combination of intercon- 
nected refrigerant-containing parts constituting one closed re- 
frigerant circuit in which a refrigerant is circulated for the 
purpose of extracting heat. 

REFRIGERATION CAPACITY RATING. Expressed as 1 
horsepower (0.75 kW), 1 ton or 12,000 Btu/h (3.5 kW), shall all 
mean the same quantity. 

REFRIGERATION MACHINERY ROOM. See "Machin- 
ery room." 

REFRIGERATION SYSTEM, ABSORPTION. A heat- 
operated, closed-refrigeration cycle in which a secondary fluid 
(the absorbent) absorbs a primary fluid (the refrigerant) that 
has been vaporized in the evaporator. 



16 



2003 INTERNATIONAL MECHANICAL CODE® 



DEFINITIONS 



Direct system. A system in which the evaporator is in direct 
contact with the material or space refrigerated, or is located 
in air-circulating passages communicating with such 
spaces. 

Indirect system. A system in which a brine coil cooled by 
the refrigerant is circulated to the material or space refriger- 
ated, or is utilized to cool the air so circulated. Indirect sys- 
tems are distinguished by the type or method of application. 

REFRIGERATION SYSTEM CLASSIFICATION. Refrig- 
eration systems are classified according to the degree of proba- 
bihty that leaked refrigerant from a failed connection, seal or 
component will enter an occupied area. The distinction is based 
on the basic design or location of the components. 

REFRIGERATION SYSTEM, MECHANICAL. A combi- 
nation of interconnected refrigeration-containing parts consti- 
tuting one closed refrigerant circuit in which a refrigerant is 
circulated for the purpose of extracting heat and in which a 
compressor is used for compressing the refrigerant vapor. 

REFRIGERATION SYSTEM, SELF-CONTAINED. A 

complete factory-assembled and tested system that is shipped 
in one or more sections and has no refrigerant-containing parts 
that are joined in the field by other than companion or block 

valves. 

REGISTERED DESIGN PROFESSIONAL. An individual 
who is registered or licensed to practice their respective design 
profession as defined by the statutory requirements of the pro- 
fessional registration laws of the state or jurisdiction in which 
the project is to be constructed. 

RETURN AIR. Air removed from an approved conditioned 
space or location and recirculated or exhausted. 

RETURN AIR SYSTEM. An assembly of connected ducts, 
plenums, fittings, registers and grilles through which air from 
the space or spaces to be heated or cooled is conducted back to 
the supply unit (see also "Supply air system"). 

ROOM HEATER VENTED. A free-standing heating unit 
burning solid or liquid fuel for direct heating of the space in and 
adjacent to that in which the unit is located. 

SAFETY VALVE. A valve that relieves pressure in a steam 
boiler by opening fully at the rated discharge pressure. The 
valve is of the spring-pop type. 

SELF-CONTAINED EQUIPMENT. Complete, fac- 
tory-assembled and tested, heating, air-conditioning or refriger- 
ation equipment installed as a single unit, and having all working 
parts, complete with motive power, in an enclosed unit of said 
machinery. 

SHAFT. An enclosed space extending through one or more 
stories of a building, connecting vertical openings in successive 
floors, or floors and the roof. 

SHAFT ENCLOSURE. The walls or construction forming 
the boundaries of a shaft. 

SMOKE DAMPER. A hsted device that is designed to resist 
die passage of air and smoke. The device is arranged to operate 
automatically, controlled by a smoke detection system, and 
when required, is capable of being positioned manually from a 
remote command station. 



SMOKE-DEVELOPED INDEX. A numerical value as- 
signed to a material tested in accordance with ASTM E 84. 

SOLID FUEL (COOKING APPLICATIONS). Applicable 
to commercial food service operations only, solid fuel is any 
bulk material such as hardwood, mesquite, charcoal or bri- 
quettes that is combusted to produce heat for cooking opera- 
tions. 

SOURCE CAPTURE SYSTEM. A mechanical exhaust sys- 
tem designed and constructed to capture air contaminants at 
their source and to exhaust such contaminants to the outdoor at- 
mosphere. 

STATIONARY FUEL CELL POWER PLANT. A self-con- 
tained package or factory-matched packages which constitute an 
automatically operated assembly of integrated systems for gen- 
erating useful electrical energy and recoverable thermal energy 
that is permanently connected and fixed in place. 

STEAM-HEATING BOILER. A boiler operated at pressures 
not exceeding 15 psi (103 kPa) for steam. 

STOP VALVE. A shutoff valve for controlling the flow of liq- 
uid or gases. 

STORY. That portion of a building included between the upper 
surface of a floor and the upper surface of the floor next above, 
except that the topmost story shall be that portion of a building 
included between the upper surface of the topmost floor and the 
ceiling or roof above. 

STRENGTH, ULTIMATE. The highest stress level that the 
component will tolerate without rupture. 

SUPPLY AIR. That air delivered to each or any space supplied 
by the air distribution system or the total air delivered to all 
spaces supplied by the air distribution system, which is 
provided for ventilating, heating, cooling, humidification, 
dehumidification and other similar purposes. 

SUPPLY AIR SYSTEM. An assembly of connected ducts, 
plenums, fittings, registers and grilles through which air, 
heated or cooled, is conducted from the supply unit to the space 
or spaces to be heated or cooled (see also "Return air system"). 

THEORETICAL AIR. The exact amount of air required to 
supply oxygen for complete combustion of a given quantity of 
a specific fuel. 

THERMAL RESISTANCE (R). A measure of the ability to 
retard the flow of heat. The ^- value is the reciprocal of thermal 
conductance. 

TLV-TWA(THRESHOLD LIMIT VALUE-TIME- 
WEIGHTED AVERAGE). The time- weighted average con- 
centration of a refrigerant or other chemical in air for a normal 
8-hour workday and a 40-hour workweek, to which nearly all 
workers are repeatedly exposed, day after day, without adverse 
effects, as adopted by the American Conference of Govern- 
ment Industrial Hygienists (ACGIH). 

TOILET ROOM. A room containing a water closet and, fre- 
quently, a lavatory, but not a bathtub, shower, spa or similar 
bathing fixture. 

TOXICITY CLASSIFICATION. Refrigerants shall be clas- 
sified for toxicity to one of two classes in accordance with 
ASHRAE 34: 



2003 INTERNATIONAL MECHANICAL CODE® 



17 



DEFINITIONS 



Class A. Refrigerants for which toxicity has not been identi- 
fied at concentrations less than or equal to 400 parts per mil- 
lion (ppm), based on data used to determine Threshold 
Limit Value-Time-Weighted Average (TLV-TWA) or con- 
sistent indices. 

Class B. Refrigerants for which there is evidence of toxicity 
at concentrations below 400 ppm, based on data used to de- 
termine TLV-TWA or consistent indices. 

TRANSITION FITTINGS, PLASTIC TO STEEL. An 

adapter for joining plastic pipe to steel pipe. The purpose of this 
fitting is to provide a permanent, pressure-tight connection be- 
tween two materials which cannot be joined directly one to an- 
other. 

UNCONFINED SPACE. A space having a volume not less 
than 50 cubic feet per 1,000 Btu/h (4.8 m^/kW) of the aggregate 
input rating of all appliances installed in that space. Rooms 
communicating directly with the space in which the appliances 
are installed, through openings not furnished with doors, are 
considered a part of the unconfmed space. 

UNIT HEATER. A self-contained appliance of the fan type, 
designed for the delivery of warm air directly into the space in 
which the appliance is located. 

UNUSUALLY TIGHT CONSTRUCTION. Construction 
meeting the following requirements: 

1 . Walls exposed to the outside atmosphere having a con- 
tinuous water vapor retarder with a rating of 1 perm 
(57 ng/s • m^ • Pa) or less with openings gasketed or 
sealed; 

2. Openable windows and doors meeting the air leakage re- 
quirements of the International Energy Conservation 
Code, Section 502.1.4; and 

3. Caulking or sealants are applied to areas, such as joints 
around window and door frames, between sole plates and 
floors, between wall-ceiling joints, between wall panels, 
at penetrations for plumbing, electrical and gas lines, and 
at other openings. 

VENT. A pipe or other conduit composed of factory- made 
components, containing a passageway for conveying combus- 
tion products and air to the atmosphere, listed and labeled for 
use with a specific type or class of appliance. 

Pellet vent. A vent listed and labeled for use with listed pel- 
let-fuel-buming appliances. 

Type L vent. A vent listed and labeled for use with the fol- 
lowing: 

1 . Oil-burning appliances that are listed for use with Type L 

vents. 

2. Gas-fired appliances that are listed for use with Type B 
vents. 

VENT CONNECTOR. The pipe that connects an approved 
fuel-fired appliance to a vent. 

VENT DAMPER DEVICE, AUTOMATIC. A device in- 
tended for installation in the venting system, in the outlet of an 
individual automatically operated fuel-burning appliance that 
is designed to open the venting system automatically when the 
appliance is in operation and to close off the venting system au- 



tomatically when the appliance is in a standby or shutdown 
condition. 

VENTILATION. The natural or mechanical process of sup- 
plying conditioned or unconditioned air to, or removing such 
air from, any space. 

VENTILATION AIR. That portion of supply air that comes 
from the outside (outdoors), plus any recirculated air that has 
been treated to maintain the desired quality of air within a des- 
ignated space. 

VENTING SYSTEM. A continuous open passageway from 
the flue collar of an appliance to the outside atmosphere for the 
purpose of removing flue or vent gases. A venting system is 
usually composed of a vent or a chimney and vent connector, if 
used, assembled to form the open passageway. 

WATER HEATER. Any heating apphance or equipment that 
heats potable water and supplies such water to the potable hot 
water distribution system. 



18 



2003 INTERNATIONAL MECHANICAL CODE® 



CHAPTER 3 

GENERAL REGULATIONS 



SECTION 301 
GENERAL 

301.1 Scope. This chapter shall govern the approval and instal- 
lation of all equipment and appliances that comprise parts of 
the building mechanical systems regulated by this code in ac- 
cordance with Section 101.2. 

301.2 Energy utilization. Heating, ventilating and 
air-conditioning systems of all structures shall be designed and 
installed for efficient utilization of energy in accordance with 
the International Energy Conservation Code. 

301.3 Fuel gas appliances and equipment. The approval and 
installation of fuel gas distribution piping and equipment, fuel 
gas-fired appliances and fuel gas-fired appUance venting sys- 
tems shall be in accordance with the International Fuel Gas 
Code. 

301.4 Listed and labeled. All appliances regulated by this code 
shall be listed and labeled, unless otherwise approved in accor- 
dance with Section 105. 

301.5 Labeling. Labeling shall be in accordance with the pro- 
cedures set forth in Sections 301.5.1 through 301.5.2.3. 

301.5.1 Testing. An approved agency shall test a representa- 
tive sample of the mechanical equipment and appliances be- 
ing labeled to the relevant standard or standards. The 
approved agency shall maintain a record of all of the tests 
performed. The record shall provide sufficient detail to ver- 
ify compliance with the test standard. 

301.5.2 Inspection and identification. The approved 
agency shall periodically perform an inspection, which shall 
be in-plant if necessary, of the mechanical equipment and 
appliances to be labeled. The inspection shall verify that the 
labeled mechanical equipment and appliances are represen- 
tative of the mechanical equipment and appliances tested. 

301.5.2.1 Independent. The agency to be approved shall 
be objective and competent. To confirm its objectivity, 
the agency shall disclose all possible conflicts of interest. 

301.5.2.2 Equipment. An approved agency shall have 
adequate equipment to perform all required tests. The 
equipment shall be periodically calibrated. 

301.5.2.3 Personnel. An approved agency shall employ 
experienced personnel educated in conducting, supervis- 
ing and evaluating tests. 

301.6 Label information. A permanent factory-applied 
name-plate(s) shall be affixed to appliances on which shall ap- 
pear in legible lettering, the manufacturer's name or trademark, 
the model number, serial number and the seal or mark of the ap- 
proved agency. A label shall also include the following: 

1 . Electrical equipment and appliances: Electrical rafing in 
volts, amperes and motor phase; identification of indi- 



vidual electrical components in volts, amperes or watts, 
motor phase; Btu/h (W) output; and required clearances. 

2. Absorption units: Hourly rating in Btu/h (W); minimum 
hourly rating for units having step or automatic modulat- 
ing controls; type of fuel; type of refrigerant; cooling ca- 
pacity in Btu/h (W); and required clearances. 

3. Fuel-burning units: Hourly rating in Btu/h (W); type of 
fuel approved for use with the appliance; and required 
clearances. 

4. Electric comfort heating appliances: Name and 
trade-mark of the manufacturer; the model number or 
equivalent; the electric rating in volts, ampacity and 
phase; Btu/h (W) output rating; individual marking for 
each electrical component in amperes or watts, volts and 
phase; required clearances from combustibles; and a seal 
indicating approval of the appliance by an approved 
agency. 

301.7 Electrical. Electrical wiring, controls and connections to 
equipment and appliances regulated by this code shall be in ac- 
cordance with the ICC Electrical Code. 

301.8 Plumbing connections. Potable water supply and build- 
ing drainage system connections to equipment and appliances 
regulated by this code shall be in accordance with the Interna- 
tional Plumbing Code. 

301.9 Fuel types. Fuel-fired appliances shall be designed for 
use with the type of fuel to which they will be connected and the 
altitude at which they are installed. Appliances that comprise 
parts of the building mechanical system shall not be converted 
for the usage of a different fuel, except where approved and 
converted in accordance with the manufacturer's instructions. 
The fuel input rate shall not be increased or decreased beyond 
the limit rating for the altitude at which the appliance is in- 
stalled. 

301.10 Vibration isolation. Where vibration isolation of 
equipment and appliances is employed, an approved means of 
supplemental restraint shall be used to accomplish the support 
and restraint. 

301.11 Repair. Defective material or parts shall be replaced or 
repaired in such a manner so as to preserve the original ap- 
proval or listing. 

301.12 Wind resistance. Mechanical equipment, appliances 
and supports that are exposed to wind shall be designed and in- 
stalled to resist the wind pressures determined in accordance 
with the International Building Code. 

[B] 301.13 Flood hazard. For structures located in flood haz- 
ard areas, mechanical systems, equipment and appliances shall 
be located at or above the design flood elevation. 

Exception: Mechanical systems, equipment and appliances 
are permitted to be located below the design flood elevation 



2003 INTERNATIONAL MECHANICAL CODE® 



19 



GENERAL REGULATIONS 



provided that they are designed and installed to prevent wa- 
ter from entering or accumulating within the components 
and to resist hydrostatic and hydrodynamic loads and 
stresses, including the effects of buoyancy, during the oc- 
currence of flooding to the design flood elevation in compli- 
ance with the flood-resistant construction requirements of 
the International Building Code. 

[B] 301.13.1 High-velocity wave action. In flood hazard 
areas subject to high- velocity wave action, mechanical sys- 
tems and equipment shall not be mounted on or penetrate 
walls intended to break away under flood loads. 

301.14 Rodent proofing. Buildings or structures and the walls 
enclosing habitable or occupiable rooms and spaces in which 
persons live, sleep or work, or in which feed, food or foodstuffs 
are stored, prepared, processed, served or sold, shall be con- 
structed to protect against the entrance of rodents in accordance 
with the International Building Code. 

301.15 Seismic resistance. When earthquake loads are appli- 
cable in accordance with the International Building Code, me- 
chanical system supports shall be designed and installed for the 
seismic forces in accordance with the International Building 
Code. 



SECTION 302 
PROTECTION OF STRUCTURE 

302.1 Structural safety. The building or structure shall not be 
weakened by the installation of mechanical systems. Where 
floors, walls, ceilings or any other portion of the building or 
structure are required to be altered or replaced in the process of 
installing or repairing any system, the building or structure 
shall be left in a safe structural condition in accordance with the 
International Building Code. 

302.2 Penetrations of floor/ceiling assemblies and 
fire-resistance-rated assemblies. Penetrations of floor/ceil- 
ing assemblies and assemblies required to have a 
fire-resistance rating shall be protected in accordance with the 
International Building Code. 

[B] 302.3 Cutting, notching and boring in wood framing. 

The cutting, notching and boring of wood framing members 
shall comply with Sections 302.3.1 through 302.3.4. 

[B] 302.3.1 Joist notching. Notches on the ends of joists 
shall not exceed one-fourth the joist depth. Holes bored in 
joists shall not be within 2 inches (5 1 mm) of the top or bot- 
tom of the joist, and the diameter of any such hole shall not 
exceed one-third the depth of the joist. Notches in the top or 
bottom of joists shall not exceed one- sixth the depth and 
shall not be located in the middle third of the span. 

[B] 302.3.2 Stud cutting and notching. In exterior walls 
and bearing partitions, any wood stud is permitted to be cut 
or notched not to exceed 25 percent of its depth. Cutting or 
notching of studs not greater than 40 percent of their depth is 
permitted in nonbearing partitions supporting no loads 
other than the weight of the partition. 

[B] 302.3.3 Bored holes. A hole not greater in diameter than 
40 percent of the stud depth is permitted to be bored in any 
wood stud. Bored holes not greater than 60 percent of the 



depth of the stud are permitted in nonbearing partitions or in 
any wall where each bored stud is doubled, provided not 
more than two such successive doubled studs are so bored. 
In no case shall the edge of the bored hole be nearer than 
0.625 inch (15.9 mm) to the edge of the stud. Bored holes 
shall not be located at the same section of stud as a cut or 
notch. 

[B] 302.3.4 Engineered wood products. Cuts, notches and 
holes bored in trusses, laminated veneer lumber, glue-lami- 
nated members and I-joists are prohibited except where the 
effects of such alterations are specifically considered in the 
design of the member. 

[B] 302.4 Alterations to trusses. Truss members and compo- 
nents shall not be cut, drilled, notched, sphced or otherwise al- 
tered in any way without written concurrence and approval of a 
registered design professional. Alterations resulting in the addi- 
tion of loads to any member (e.g., HVAC equipment, water heat- 
ers) shall not be permitted without verification that the truss is 
capable of supporting such additional loading. 

[B] 302.5 Cutting, notching and boring in steel framing. The 

cutting, notching and boring of steel framing members shall 
comply with Sections 302.5.1 through 302.5.3. 

[B] 302.5.1 Cutting, notching and boring holes in struc- 
tural steel framing. The cutting, notching and boring of 
holes in structural steel framing members shall be as pre- 
scribed by the registered design professional. 

[B] 302.5.2 Cutting, notching and boring holes in 
cold-formed steel framing. Flanges and lips of load-bear- 
ing cold-formed steel framing members shall not be cut or 
notched. Holes in webs of load-bearing cold-formed steel 
framing members shall be permitted along the centerline of 
the web of the framing member and shall not exceed the di- 
mensional hmitations, penetration spacing or minimum 
hole edge distance as prescribed by the registered design 
professional. Cutting, notching and boring holes of steel 
floor/roof decking shall be as prescribed by the registered 
design professional. 

[B] 302.5.3 Cutting, notching and boring holes in 
non-structural cold-formed steel wall framing. Flanges 
and lips of nonstructural cold-formed steel wall studs shall 
not be cut or notched. Holes in webs of nonstructural 
cold-formed steel wall studs shall be permitted along the 
center-line of the web of the framing member, shall not ex- 
ceed 1.5 inches (38 mm) in width or 4 inches (102 mm) in 
length, and shall not be spaced less than 24 inches (610 mm) 
center to center from another hole or less than 10 inches 
(254 mm) from the bearing end. 



SECTION 303 
EQUIPMENT AND APPLIANCE LOCATION 

303.1 General. Equipment and appliances shall be located as 
required by this section, specific requirements elsewhere in this 
code and the conditions of the equipment and appliance listing. 

303.2 Hazardous locations. Appliances shall not be located in 
a hazardous location unless Usted and approved for the specific 
installation. 



20 



2003 INTERNATIONAL MECHANICAL CODE® 



GENERAL REGULATIONS 



303.3 Prohibited locations. Fuel-fired appliances shall not be 
located in, or obtain combustion air from, any of the following 
rooms or spaces: 

1. Sleeping rooms. 

2. Bathrooms. 

3. Toilet rooms. 

4. Storage closets. 

5. Surgical rooms. 

Exception: This section shall not apply to the following ap- 
phances: 

1 . Direct- vent appHances that obtain all combustion air 
directly from the outdoors. 

2. Solid fuel-fired appliances, provided that the room is 
not a confined space and the building is not of unusu- 
ally tight construction. 

3. Appliances installed in a dedicated enclosure in 
which all combustion air is taken directly from the 
outdoors, in accordance with Section 703. Access to 
such enclosure shall be through a solid door, 
weather-stripped in accordance with the exterior door 
air leakage requirements of the International Energy 
Conservation Code and equipped with an approved 
self-closing device. 

303.4 Protection from damage. Apphances shall not be in- 
stalled in a location where subject to mechanical damage un- 
less protected by approved barriers. 

303.5 Indoor locations. Fuel-fired furnaces and boilers installed 
in closets and alcoves shall be listed for such installation. For 
purposes of this section, a closet or alcove shall be defined as a 
room or space having a volume less than 12 times the total vol- 
ume of fuel-fired appliances other than boilers and less than 16 
times the total volume of boilers. Room volume shall be com- 
puted using the gross floor area and the actual ceihng height up 
to a maximum computation height of 8 feet (2438 mm). 

303.6 Outdoor locations. Apphances installed in other than 
indoor locations shall be listed and labeled for outdoor installa- 
tion. 

303.7 Pit locations. Apphances installed in pits or excavations 
shall not come in direct contact with the surrounding soil. The 
sides of the pit or excavation shall be held back a minimum of 
12 inches (305 mm) from the appliance. Where the depth ex- 
ceeds 12 inches (305 mm) below adjoining grade, the walls of 
the pit or excavation shall be lined with concrete or masonry. 
Such concrete or masonry shall extend a minimum of 4 inches 
(102 nmi) above adjoining grade and shall have sufficient lat- 
eral load-bearing capacity to resist collapse. The appliance 
shall be protected from flooding in an approved manner. 

[B] 303.8 Elevator shafts. Mechanical systems shall not be lo- 
cated in an elevator shaft. 



SECTION 304 
INSTALLATION 

304.1 General. Equipment and appliances shall be installed as 
required by the terms of their approval, in accordance with the 



conditions of the listing, the manufacturer's installation instruc- 
tions and this code. Manufacturer's installation instructions shall 
be available on the job site at the time of inspection. 

304.2 Conflicts. Where conflicts between this code and the 
conditions of listing or the manufacturer's installation instruc- 
tions occur, the provisions of this code shall apply. 

Exception: Where a code provision is less restrictive than 
the conditions of the listing of the equipment or appliance or 
the manufacturer's installation instructions, the conditions 
of the listing and the manufacturer's installation instructions 
shall apply. 

304.3 Elevation of ignition source. Equipment and apphances 
having an ignition source and located in hazardous locations 
and public garages, private garages, repair garages, automotive I 
motor-fuel-dispensing facihties and parking garages shall be ' 
elevated such that the source of ignition is not less than 18 
inches (457 mm) above the floor surface on which the equip- 
ment or appliance rests. Such equipment and apphances shall 
not be installed in Group H occupancies or control areas where 
open use, handling or dispensing of combustible, flammable or 
explosive materials occurs. For the purpose of this section, 
rooms or spaces that are not part of the living space of a dwell- 
ing unit and that communicate directly with a private garage 
through openings shall be considered to be part of the private 
garage. 

304.4 Hydrogen generating and refueling operations. Ven- 
tilation shall be required in accordance with Section 304.4.1, 
304,4.2 or 304.4.3 in public garages, private garages, repair ga- 
rages, automotive motor-fuel-dispensing facilities and parking 
garages which contain hydrogen generating appliances or refu- 
eling systems. Such spaces shall be used for the storage of not 
more than three hydrogen-fueled passenger motor vehicles and 
have a floor area not exceeding 850 square feet (79 square me- 
ters). The maximum rated output capacity of hydrogen gener- 
ating appliances shall not exceed 4 SCFM of hydrogen for each 
250 square feet (23.2 square meters) of floor area in such 
spaces. Such equipment and appliances shall not be installed in 
Group H occupancies except where the occupancy is specifi- 
cally designed for hydrogen use, or in control areas where 
open-use, handling or dispensing of combustible, flammable 
or explosive materials occurs. For the purpose of this section, 
rooms or spaces that are not part of the living space of a dwell- 
ing unit and that communicate directly with a private garage 
through openings shall be considered to be part of the private 
garage. 

304.4.1 Natural ventilation. Indoor locations intended for 
hydrogen generating or refueling operations shall commu- 
nicate with the outdoors in accordance with Sections 
304.4.1.1 and 304.4.1.2. The minimum dimension of air 
openings shall be not less than 3 inches (76 mm). Where 
ducts are used, they shall be of the same cross-sectional area 
as the free area of the openings to which they connect. In 
such locations, equipment and appliances having an igni- 
tion source shall be located such that the source of ignition is 
not less than 12 inches (228 nun) below the ceiling. 

304.4.1.1 Two openings. Two permanent openings, one 
located entirely within 12 inches (305 mm) of the ceihng 
of the garage, and one located entirely within 12 inches 



2003 INTERNATIONAL MECHANICAL CODE® 



21 



GENERAL REGULATIONS 



(305 mm) of the floor of the garage, shall be provided in 
the same exterior wall. The openings shall communi- 
cate directly, or by ducts, with the outdoors. Each open- 
ing shall directly communicate with the outdoors 
horizontally, and have a minimum free area of I2 
square foot per 1,000 cubic feet (1641 mm /m ) of ga- 
rage volume. 

304.4.1.2 Louvers and grilles. In calculating free area 
required by Section 304.4.1, the required size of open- 
ings shall be based on the net free area of each opening. 
If the free area through a design of louver or grille is 
known, it shall be used in calculating the size opening 
required to provide the free area specified. If 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. Lou- 
vers and grilles shall be fixed in the open position. 

304.4.2 Mechanical ventilation. Indoor locations in- 
tended for hydrogen generating or refueling operations 
shall be ventilated in accordance with Section 502.16. 

304.4.3 Specially engineered installations. As an alter- 
native to the provisions of Sections 304.4. 1 and 304.4.2 the 
necessary supply of air for ventilation and dilution of flam- 
mable gases shall be provided by an approved engineered 
system. 

304.5 Public garages. Appliances located in public garages, 
motor fuel-dispensing facilities, repair garages or other areas 
frequented by motor vehicles, shall be installed a minimum of 
8 feet (2438 mm) above the floor. Where motor vehicles ex- 
ceed 6 feet ( 1 829 mm) in height and are capable of passing un- 
der an appliance, appliances shall be installed a minimum of 2 
feet (610 mm) higher above the floor than the height of the 
tallest vehicle. 

Exception: The requirements of this section shall not ap- 
ply where the appliances are protected from motor vehicle 
impact and installed in accordance with Section 304.3 and 
NFPA 88B. 

304.6 Private garages. Appliances located in private garages 
and carports shall be installed with a minimum clearance of 6 
feet (1829 mm) above the floor. 

Exception: The requirements of this section shall not ap- 
ply where the appliances are protected from motor vehicle 
impact and installed in accordance with Section 304.3. 

304.7 Construction and protection. Boiler rooms and fur- 
nace rooms shall be protected as required by the International 
Building Code. 

304.8 Clearances to combustible construction. Heat-pro- 
ducing equipment and appliances shall be installed to main- 
tain the required clearances to combustible construction as 
specified in the listing and manufacturer's instructions. Such 
clearances shall be reduced only in accordance with Section 
308. Clearances to combustibles shall include such consider- 



ations as door swing, drawer pull, overhead projections or 
shelving and window swing, shutters, coverings and drapes. 
Devices such as doorstops or limits, closers, drapery ties or 
guards shall not be used to provide the required clearances. 

304.9 Clearances from grade. Equipment and appliances in- 
stalled at grade level shall be supported on a level concrete 
slab or other approved material extending above adjoining 
grade or shall be suspended a minimum of 6 inches (152 mm) 
above adjoining grade. 

304.10 Guards. Guards shall be provided where appliances, 
equipment, fans or other components that require service are 
located within 10 feet (3048 mm) of a roof edge or open side 
of a walking surface and such edge or open side is located 
more than 30 inches (762 mm) above the floor, roof or grade 
below. The guard shall extend not less than 30 inches (762 
mm) beyond each end of such appliance, equipment, fan or 
component and the top of the guard shall be located not less 
than 42 inches (1067 mm) above the elevated surface adjacent 
to the guard. The guard shall be constructed so as to prevent 
the passage of a 21-inch-diameter (533 mm) sphere and shall 
comply with the loading requirements for guards specified in 
the International Building Code. 

304.11 Area served. Appliances serving different areas of a 
building other than where they are installed shall be perma- 
nently marked in an approved manner that uniquely identifies 
the appliance and the area it serves. 



SECTION 305 
PIPING SUPPORT 

305.1 General. All mechanical system piping shall be supported 
in accordance with this section. 

305.2 Materials. Pipe hangers and supports shall have suffi- 
cient strength to withstand all anticipated static and specified 
dynamic loading conditions associated with the intended use. 
Pipe hangers and supports that are in direct contact with piping 
shall be of approved materials that are compatible with the pip- 
ing and that will not promote galvanic action. 

305.3 Structural attachment. Hangers and anchors shall be 
attached to the building construction in an approved manner. 

305.4 Interval of support. Piping shall be supported at dis- 
tances not exceeding the spacing specified in Table 305.4, or in 
accordance with MSS SP-69. 

305.5 Protection against physical damage. In concealed loca- 
tions where piping, other than cast-iron or steel, is installed 
through holes or notches in studs, joists, rafters or similar mem- 
bers less than 1.5 inches (38 mm) from the nearest edge of the 
member, the pipe shall be protected by shield plates. Protective 
shield plates shall be a minimum of 0.062-inch-thick (1.6 mm) 
steel, shall cover the area of the pipe where the member is notched 
or bored, and shall extend a minimum of 2 inches (5 1 mm) above 
sole plates and below top plates. 



22 



2003 INTERNATIONAL MECHANICAL CODE® 



GENERAL REGULATIONS 



TABLE 305.4 
PIPING SUPPORT SPACING^ 



PIPING MATERIAL 


MAXIMUM 

HORIZONTAL 

SPACING 

(feet) 


MAXIMUM 

VERTICAL 

SPACING 

(feet) 


ABS pipe 


4 


10^= 


Aluminum pipe and tubing 


10 


15 


Brass pipe 


10 


10 


Brass tubing, 1 '/^-inch diameter 
and smaller 


6 


10 


Brass tubing, lV2-inch diameter 
and larger 


10 


10 


Cast-iron pipe'' 


5 


15 


Copper or copper-alloy pipe 


12 


10 


Copper or copper-alloy tubing, 
1 V^-inch diameter and smaller 


6 


10 


Copper or copper-alloy tubing, 
1 7^-inch diameter and larger 


10 


10 


CPVC pipe or tubing, 1 inch 
and smaller 


3 


10' 


CPVC pipe or tubing 1 V^-inch 
and larger 


4 


10' 


Steel pipe 


12 


15 


Steel tubing 


8 


10 


Lead pipe 


Continuous 


4 


PB pipe or tubing 


2% 
(32 inches) 


4 


PEX tubing 


1% 
(32 inches) 


10' 


PVC pipe 


4 


10' 



For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm. 

a. See Section 301.14. 

b. The maximum horizontal spacing of cast-iron pipe hangers shall be in- 
creased to 10 feet where 10-foot lengths of pipe are installed. 

c. Mid-story guide. 



SECTION 306 
ACCESS AND SERVICE SPACE 

306.1 Clearances for maintenance and replacement. Clear- 
ances around appliances to elements of permanent construction, 
including other installed equipment and appliances, shall be suf- 
ficient to allow inspection, service, repair or replacement with- 
out removing such elements of permanent construction or 
disabling the function of a required fire-resistance-rated assem- 
bly. 

306.1.1 Central furnaces. Central furnaces within com- 
partments or alcoves shall have a minimum working space 
clearance of 3 inches (76 mm) along the sides, back and top 
with a total width of the enclosing space being at least 12 
inches (305 mm) wider than the furnace. Furnaces having a 
firebox open to the atmosphere shall have at least 6 inches 
(152 mm) working space along the front combustion cham- 



ber side. Combustion air openings at the rear or side of the 
compartment shall comply with the requirements of Chap- 
ter?. 

Exception: This section shall not apply to replacement 
appUances installed in existing compartments and alcoves 
where the working space clearances are in accordance 
with the equipment or appliance manufacturer's installa- 
tion instructions. 

306.2 Appliances in rooms. Rooms containing appliances re- 
quiring access shall be provided with a door and an unobstructed 
passageway measuring not less than 36 inches (914 nmi) wide 
and 80 inches (2032 mm) high. 

Exception: Within a dwelling unit, appliances installed in a 
compartment, alcove, basement or similar space shall be ac- 
cessed by an opening or door and an unobstructed passage- 
way measuring not less than 24 inches (610 mm) wide and 
large enough to allow removal of the largest appliance in the 
space, provided that a level service space of not less than 30 
inches (762 mm) deep and the height of the appliance, but 
not less than 30 inches (762 mm), is present at the front or 
service side of the appUance with the door open. 

306.3 Appliances in attics. Attics containing appliances re- 
quiring access shall be provided with an opening and unob- 
structed passageway large enough to allow removal of the 
largest appliance. The passageway shall not be less than 30 
inches (762 mm) high and 22 inches (559 mm) wide and not 
more than 20 feet (6096 mm) in length measured along the cen- 
terline of the passageway from the opening to the appliance. 
The passageway shall have continuous solid flooring not less 
than 24 inches (610 mm) wide. A level service space not less 
than 30 inches (762 mm) deep and 30 inches (762 mm) wide 
shall be present at the front or service side of the appliance. The 
clear access opening dimensions shall be a minimum of 20 
inches by 30 inches (508 mm by 762 mm), where such dimen- 
sions are large enough to allow removal of the largest appli- 
ance. 

Exception: The passageway and level service space are not 
required where the appliance is capable of being serviced 
and removed through the required opening. 

306.3.1 Electrical requirements. A lighting fixture con- 
trolled by a switch located at the required passageway open- 
ing and a receptacle outlet shall be provided at or near the 
appliance location in accordance with the ICC Electrical 
Code. 

306.4 Appliances under floors. Underfloor spaces containing 
appliances requiring access shall be provided with an access 
opening and unobstructed passageway large enough to remove 
the largest appliance. The passageway shall not be less than 30 
inches (762 mm) high and 22 inches (559 mm) wide, nor more 
than 20 feet (6096 mm) in length measured along the centerline 
of the passageway from the opening to the appliance. A level 
service space not less than 30 inches (762 mm) deep and 30 
inches (762 mm) wide shall be present at the front or service 
side of the appliance. If the depth of the passageway or the ser- 
vice space exceeds 12 inches (305 mm) below the adjoining 
grade, the walls of the passageway shall be lined with concrete 
or masonry. Such concrete or masonry shall extend a minimum 
of 4 inches (102 mm) above; the adjoining grade and shall have 



2003 INTERNATIONAL MECHANICAL CODE® 



23 



GENERAL REGULATIONS 



sufficient lateral-bearing capacity to resist collapse. The clear 
access opening dimensions shall be a minimum of 22 inches by 
30 inches (559 nmi by 762 mm), where such dimensions are 
large enough to allow removal of the largest appliance. 

Exception: The passageway is not required where the level 
service space is present when the access is open and the ap- 
pliance is capable of being serviced and removed through 
the required opening. 

306.4.1 Electrical requirements. A Ughting fixture con- 
trolled by a switch located at the required passageway open- 
ing and a receptacle outlet shall be provided at or near the 
appliance location in accordance with the ICC Electrical 
Code. 

306.5 Equipment and appliances on roofs or elevated struc- 
tures. Where equipment and appliances requiring access are 
installed on roofs or elevated structures at a height exceeding 
16 feet (4877 mm), such access shall be provided by a perma- 
nent approved means of access, the extent of which shall be 
from grade or floor level to the equipment and appliances' level 
service space. Such access shall not require climbing over ob- 
structions greater than 30 inches (762 mm) high or walking on 
roofs having a slope greater than 4 units vertical in 12 units hor- 
izontal (33-percent slope). 

Permanent ladders installed to provide the required access 
shall comply with the following minimum design criteria: 

1. The side railing shall extend above the parapet or roof 
edge not less than 30 inches (762 nrun). 

2. Ladders shall have rung spacing not to exceed 14 inches 
(356 mm) on center. 

3. Ladders shall have a toe spacing not less than 6 inches 
(152 mm) deep. 

4. There shall be a minimum of 1 8 inches ( 457 mm) be- 
tween rails. 

5. Rungs shall have a minimum 0.75-inch (19 mm) diame- 
ter and be capable of withstanding a 300-pound (136.1 
kg) load. 

6. Ladders over 30 feet (9144 mm) in height shall be pro- 
vided with offset sections and landings capable of with- 
standing 100 pounds (488.2 kg/m^) per square foot. 

7. Ladders shall be protected against corrosion by approved 
means. 

Catwalks installed to provide the required access shall be not 
less than 24 inches (610 mm) wide and shall have railings as re- 
quired for service platforms. 

Exception: This section shall not apply to Group R-3 occu- 
pancies. 

306.6 Sloped roofs. Where appliances are installed on a roof 
having a slope of three units vertical in 12 units horizontal 
(25-percent slope) or greater and having an edge more than 30 
inches (762 mm) above grade at such edge, a level platform 
shall be provided on each side of the appliance to which access 
is required by the manufacturer's installation instructions for 
service, repair or maintenance. The platform shall not be less 
than 30 inches (762 mm) in any dimension and shall be pro- 
vided with guards in accordance with Section 304.10. 



SECTION 307 
CONDENSATE DISPOSAL 

307.1 Fuel-burning appliances. Liquid combustion 
by-products of condensing appliances shall be collected and 
discharged to an approved plumbing fixture or disposal area in 
accordance with the manufacturer's installation instructions. 
Condensate piping shall be of approved corrosion-resistant 
material and shall not be smaller than the drain connection on 
the appliance. Such piping shall maintain a minimum horizon- 
tal slope in the direction of discharge of not less than one-eighth 
unit vertical in 12 units horizontal (1 -percent slope). 

307.2 Evaporators and cooling coils. Condensate drain sys- 
tems shall be provided for equipment and appliances containing 
evaporators or cooling coils. Condensate drain systems shall be 
designed, constructed and installed in accordance with Sections 
307.2.1 through 307.2.4. 

307.2.1 Condensate disposal. Condensate from all cooling 
coils and evaporators shall be conveyed from the drain pan 
outlet to an approved place of disposal. Condensate shall not 
discharge into a street, alley or other areas so as to cause a 
nuisance. 

307.2.2 Drain pipe materials and sizes. Components of the 
condensate disposal system shall be cast iron, galvanized steel, 
copper, cross-linked polyethylene, polybutylene, polyethyl- I 
ene, ABS, CPVC or PVC pipe or tubing. All components shall 
be selected for the pressure and temperature rating of the instal- 
lation. Condensate waste and drain line size shall be not less 
than V4-inch (19 mm) intemal diameter and shall not decrease 
in size from the drain pan connection to the place of condensate 
disposal. Where the drain pipes from more than one unit are 
manifolded together for condensate drainage, the pipe or tub- 
ing shall be sized in accordance with an approved method. All 
horizontal sections of drain piping shall be installed m uniform 
alignment at a uniform slope. 

307.2.3 Auxiliary and secondary drain systems. In addi- 
tion to the requirements of Section 307.2.1, a secondary 
drain or auxiliary drain pan shall be required for each cool- 
ing or evaporator coil where damage to any building compo- 
nents will occur as a result of overflow from the equipment 
drain pan or stoppage in the condensate drain piping. One of 
the following methods shall be used: 

1 . An auxiliary drain pan with a separate drain shall be 
provided under the coils on which condensation will 
occur. The auxiliary pan drain shall discharge to a 
conspicuous point of disposal to alert occupants in the 
event of a stoppage of the primary drain. The pan shall 
have a minimum depth of 1.5 inches (38 mm), shall 
not be less than 3 inches (76 mm) larger than the unit 
or the coil dimensions in width and length and shall be 
constructed of corrosion-resistant material. Metallic 
pans shall have a minimum thickness of not less than 
0.0276-inch (0.7 mm) galvanized sheet metal. Non- 
metallic pans shall have a minimum thickness of not 
less than 0.0625 inch (1.6 mm). 

2. A separate overflow drain line shall be connected to 
the drain pan provided with the equipment. Such over- 
flow drain shall discharge to a conspicuous point of 
disposal to alert occupants in the event of a stoppage 



24 



2003 INTERNATIONAL MECHANICAL CODE® 



GENERAL REGULATIONS 



of the primary drain. The overflow drain line shall 
connect to the drain pan at a higher level than the pri- 
mary drain connection. 

3. An auxiliary drain pan without a separate drain line 
shall be provided under the coils on which condensate 
will occur. Such pan shall be equipped with a wa- 
ter-level detection device that will shut off the equip- 
ment served prior to overflow of the pan. The 
auxiliary drain pan shall be constructed in accordance 
with Item 1 of this section. 

307.2.4 Traps. Condensate drains shall be trapped as re- 
quired by the equipment or appliance manufacturer. 



SECTION 308 
CLEARANCE REDUCTION 

308.1 Scope. This section shall govern the reduction in re- 
quired clearances to combustible materials and combustible as- 
semblies for chimneys, vents, kitchen exhaust equipment, 
mechanical appliances, and mechanical devices and equip- 
ment. 

308.2 Listed appliances and equipment. The reduction of the 
required clearances to combustibles for listed and labeled ap- 
pliances and equipment shall be in accordance with the require- 
ments of this section except that such clearances shall not be 
reduced where reduction is specifically prohibited by the terms 
of the appliance or equipment listing. 

308.3 Protective assembly construction and installation. 

Reduced clearance protective assembUes, including structural 
and support elements, shall be constructed of noncombustible 
materials. Spacers utilized to maintain an airspace between the 
protective assembly and the protected material or assembly 
shall be noncombustible. Where a space between the protective 
assembly and protected combustible material or assembly is 
specified, the same space shall be provided around the edges of 
the protective assembly and the spacers shall be placed so as to 
allow air circulation by convection in such space. Protective as- 
semblies shall not be placed less than 1 inch (25 mm) from the 
mechanical appliances, devices or equipment, regardless of the 
allowable reduced clearance. 

308.4 Allowable reduction. The reduction of required clear- 
ances to combustible assemblies or combustible materials shall 
be based on the utilization of a reduced clearance protective as- 
sembly in accordance with Section 308.5 or 308.6. 

308.5 Labeled assemblies. The allowable clearance reduction 
shall be based on an approved reduced clearance protective as- 
sembly that has been tested and bears the label of an approved 
agency. 

308.6 Reduction table. The allowable clearance reduction shall 
be based on one of the methods specified in Table 308.6. Where 
required clearances are not hsted in Table 308.6, the reduced 
clearances shall be determined by linear interpolation between 
the distances listed in the table. Reduced clearances shall not be 
derived by extrapolation below the range of the table. 

308.7 Solid fuel-burning appliances. The clearance reduction 
methods specified in Table 308.6 shall not be utilized to reduce 
the clearance required for solid fuel-burning appliances that are 



labeled for installation with clearances of 12 inches (305 mm) 
or less. Where appHances are labeled for installation with 
clearances of greater than 12 inches (305 mm), the clearance 
reduction methods of Table 308.6 shall not reduce the clear- 
ance to less than 12 inches (305 mm). 

308.8 Masonry chimneys. The clearance reduction methods 
specified in Table 308.6 shall not be utilized to reduce the clear- 
ances required for masonry chimneys as specified in Chapter 8 
and the International Building Code. 

308.9 Chimney connector pass-throughs. The clearance re- 
duction methods specified in Table 308.6 shall not be utiUzed 
to reduce the clearances required for chimney connector 
pass-throughs as specified in Section 803.10.4. 

308.10 Masonry fireplaces. The clearance reduction methods 
specified in Table 308.6 shall not be utilized to reduce the clear- 
ances required for masonry fireplaces as specified in Chapter 8 
and the International Building Code. 

308.11 Kitchen exhaust ducts. The clearance reduction meth- 
ods specified in Table 308.6 shall not be ufiHzed to reduce the 
minimum clearances required by Section 506.3.10 for kitchen 
exhaust ducts enclosed in a shaft. 



[B] SECTION 309 
TEMPERATURE CONTROL 

[B] 309.1 Space-heating systems. Interior spaces intended for 
human occupancy shall be provided with active or passive 
space-heating systems capable of maintaining a minimum in- 
door temperature of 68°F (20°C) at a point 3 feet (914 mm) 
above floor on the design heating day. The installation of porta- 
ble space heaters shall not be used to achieve compliance with 
this section. 

Exception: Interior spaces where the primary purpose is not 
associated with human comfort. 



[F] SECTION 310 
EXPLOSION CONTROL 

[F] 310.1 Required. Structures occupied for purposes involv- 
ing explosion hazards shall be provided with explosion control 
where required by the International Fire Code. Explosion 
control systems shall be designed and installed in accordance 
with the International Fire Code. 



[F] SECTION 311 
SMOKE AND HEAT VENTS 

[F] 311.1 Required. Approved smoke and heat vents shall be 
installed in the roofs of one-story buildings where required by 
the International Fire Code. Smoke and heat vents shall be de- 
signed and installed in accordance with the International Fire 
Code. 



SECTION 312 
HEATING AND COOLING LOAD CALCULATIONS 

312.1 Load calculations. Heating and cooling system design 
loads for the purpose of sizing systems, appliances and equip- 



2003 INTERNATIONAL MECHANICAL CODE® 



25 



GENERAL REGULATIONS 



ment shall be determined in accordance with the procedures 
described in the ASHRAE Handbook of Fundamentals. 
Heating and cooling loads shall be adjusted to account for load 
reductions that are achieved when energy recovery systems are 
utilized in the HVAC system in accordance with the ASHRAE 
Handbook - HVAC Systems and Equipment. Alternatively, de- 



sign loads shall be determined by an approvedequivalent com- 
putation procedure, using the design parameters specified in 
Chapter 3 of the International Energy Conservation Code. 



TABLE 308.6 
CLEARANCE REDUCTION METHODS 



TYPE OF PROTECTIVE ASSEMBLY^ 


REDUCED CLEARANCE WITH PROTECTION (Inches)^ 


Horizontal combustible assemblies 
located above the heat source 


Horizontal combustible assemblies 
located beneath the heat source and 
all vertical combustible assemblies 


Required clearance to combustibles 
without protection (inches)" 


Required clearance to combustible 
without protection (inches)^ 


36 


18 


9 


6 


36 


18 


9 


6 


Galvanized sheet metal, minimum nominal thickness of 0.024 
inch (No. 24 Gage), mounted on 1-inch glass fiber or mineral 
wool batt reinforced with wire on the back, 1 inch off the 
combustible assembly 


18 


9 


5 


3 


12 


6 


3 


3 


Galvanized sheet metal, minimum nominal thickness of 0.024 
inch (No. 24 Gage), spaced 1 inch off the combustible 
assembly 


18 


9 


5 


3 


12 


6 


3 


2 


Two layers of galvanized sheet metal, minimum nominal 
thickness of 0.024 inch (No. 24 Gage), having a 1-inch 
airspace between layers, spaced 1 inch off the combustible 
assembly 


18 


9 


5 


3 


12 


6 


3 


3 


Two layers of galvanized sheet metal, minimum nominal 
thickness of 0.024 inch (No. 24 Gage), having 1 inch of 
fiberglass insulation between layers, spaced 1 inch off the 
combustible assembly 


18 


9 


5 


3 


12 


6 


3 


3 


0.5-inch inorganic insulating board, over 1 inch of fiberglass or 
mineral wool ba«, against the combustible assembly 


24 


12 


6 


4 


18 


9 


5 


3 


3.5-inch brick wall, spaced 1 inch off the combustible wall 














12 


6 


6 


6 


3. 5 -inch brick wall, against the combustible wall 


— 


— 


— 


— 


24 


12 


6 


5 



For SI: 1 inch = 25.4 mm, °C = [(°F)-32]/1.8, 1 pound per cubic foot = 16.02 kg/m^ 1.0 Btu • in/ft^ • h • °F = 0.144 W/m^ • K. 

a. Mineral wool and glass fiber batts (blanket or board) shall have a minimum density of 8 pounds per cubic foot and a minimum melting point of 1 ,500°F. Insulation 

material utilized as part of a clearance reduction system shall have a thermal conductivity of 1.0 Btu • in./(ft^ • h • °F) or less. Insulation board shall be formed of 

noncombustible material. 



26 



2003 INTERNATIONAL MECHANICAL CODE® 



CHAPTER 4 

VENTILATION 



SECTION 401 
GENERAL 

401.1 Scope. This chapter shall govern the ventilation of 
spaces within a building intended to be occupied. This chapter 
does not govern the requirements for smoke control systems. 

401.2 Ventilation required. Every occupied space shall be 
ventilated by natural means in accordance with Section 402 or 
by mechanical means in accordance with Section 403. 

401.3 When required. Ventilation shall be provided during the 
periods that the room or space is occupied. 

[B] 401.4 Exits. Equipment and ductwork for exit enclosure 
ventilation shall comply with one of the following items: 

1. Such equipment and ductwork shall be located exterior to 
the building and shall be directly connected to the exit en- 
closure by ductwork enclosed in construction as required 
by the International Building Code for shafts. 

2. Where such equipment and ductwork is located within the 
exit enclosure, the intake air shall be taken directly from 
the outdoors and the exhaust air shall be discharged di- 
rectly to the outdoors, or such air shall be conveyed 
through ducts enclosed in construction as required by the 
International Building Code for shafts. 

3. Where located within the building, such equipment and 
ductwork shall be separated from the remainder of the 
building, including other mechanical equipment, with 
construction as required by the International Building 
Code for shafts. 

In each case, openings into fire-resistance-rated construc- 
tion shall be limited to those needed for maintenance and oper- 
ation and shall be protected by self-closing fire- 
resistance-rated devices in accordance with the International 
Building Code for enclosure wall opening protectives. 

Exit enclosure ventilation systems shall be independent of 
other building ventilation systems. 

401.5 Opening location. Outdoor air exhaust and intake open- 
ings shall be located a minimum of 10 feet (3048 mm) from lot 
lines or buildings on the same lot. Where openings front on a 
street or public way, the distance shall be measured to the cen- 
terline of the street or public way. 

Exception: Group R-3. 

401.5.1 Intake openings. Mechanical and gravity outdoor air 
intake openings, shall be located a minimum of 10 feet (3048 
mm) from any hazardous or noxious contaminant such as 
vents, chimneys, plumbing vents, streets, alleys, parking lots 
and loading docks, except as otherwise specified in this code. 
Where a source of contaminant is located within 10 feet 
(3048 mm) of an intake opening, such opening shall be lo- 



cated a minimum of 2 feet (610 mm) below the contaminant 
source. 

401.5.2 Exhaust openings. Outdoor exhaust openings shall 
be located so as not to create a nuisance. Exhaust air shall 
not be directed onto walkways. 

[B] 401.5.3 Flood hazard. For structures located in flood 
hazard areas, outdoor exhaust openings shall be at or above 
the design flood elevation. 

401.6 Outdoor opening protection. Air exhaust and intake 
openings that terminate outdoors shall be protected with corro- 
sion-resistant screens, louvers or grilles. Openings in louvers, 
grilles and screens shall be sized in accordance with Table 401 .6, 
and shall be protected against local weather conditions. Outdoor 
air exhaust and intake openings located in exterior walls shall 
meet the provisions for exterior wall opening protectives in ac- 
cordance with the International Building Code. 

TABLE 401.6 

OPENING SIZES IN LOUVERS, GRILLES AND 

SCREENS PROTECTING OUTDOOR EXHAUST AND 

AIR INTAKE OPENINGS 



OUTDOOR OPENING TYPE 


MINIMUM AND MAXIMUM OPENING 

SIZES IN LOUVERS, GRILLES AND 

SCREENS MEASURED IN ANY 

DIRECTION 


Exhaust openings 


Not < V4 inch and not > ^/^ inch 


Intake openings in residential 
occpancies 


Not < V4 inch and not > '/^ inch 


Intake openings in other than 
residential occupancies 


> V4 inch and not > 1 inch 



For SI: 1 inch = 25.4 mm. 

401.7 Contaminant sources. Stationary local sources produc- 
ing air-borne particulates, heat, odors, fumes, spray, vapors, 
smoke or gases in such quantities as to be irritating or injurious 
to health shall be provided with an exhaust system in accor- 
dance with Chapter 5 or a means of collection and removal of 
the contaminants. Such exhaust shall discharge directly to an 
approved location at the exterior of the building. 



[B] SECTION 402 
NATURAL VENTILATION 

402.1 Natural ventilation. Natural ventilation of an occupied 
space shall be through windows, doors, louvers or other open- 
ings to the outdoors. The operating mechanism for such open- 
ings shall be provided with ready access so that the openings 
are readily controllable by the building occupants. 

402.2 Ventilation area required. The minimum openable area 
to the outdoors shall be 4 percent of the floor area being venti- 
lated. 



2003 INTERNATIONAL MECHANICAL CODE® 



27 



VENTILATION 



402.3 Adjoining spaces. Where rooms and spaces without 
openings to the outdoors are ventilated through an adjoining 
room, the opening to the adjoining rooms shall be unobstructed 
and shall have an area not less than 8 percent of the floor area of 
the interior room or space, but not less than 25 square feet (2.3 
m^). The minimum openable area to the outdoors shall be based 
on the total floor area being ventilated. 

Exception: Exterior openings required for ventilation shall 
be permitted to open into a thermally isolated sunroom addi- 
tion or patio cover, provided that the openable area between 
the sunroom addition or patio cover and the interior room 
shall have an area of not less than 8 percent of the floor area 
of the interior room or space, but not less than 20 square feet 
( 1 .86 m^). The minimum openable area to the outdoors shall 
be based on the total floor area being ventilated. 

402.4 Openings below grade. Where openings below grade 
provide required natural ventilation, the outside horizontal clear 
space measured perpendicular to the opening shall be one and 
one-half times the depth of the opening. The depth of the open- 
ing shall be measured from the average adjoining ground level to 
the bottom of the opening. 



SECTION 403 
MECHANICAL VENTILATION 

403.1 Ventilation system. Mechanical ventilation shall be pro- 
vided by a method of supply air and return or exhaust air. The 
amount of supply an* shall be approximately equal to the 
amount of return and exhaust air. The system shall not be pro- 
hibited from producing negative or positive pressure. The sys- 
tem to convey ventilation air shall be designed and installed in 
accordance with Chapter 6. 

Ventilation supply systems shall be designed to deliver the 
required rate of supply air to the occupied zone within an occu- 
pied space. The occupied zone shall have boundaries measured 
at 3 inches (76 mm) and 72 inches (1829 mm) above the floor 
and 24 inches (610 mm) from the enclosing walls. 

403.2 Outdoor air required. The minimum ventilation rate of 
required outdoor air shall be determined in accordance with 
Section 403.3. 

403.2.1 Recirculation of air. The air required by Section 
403.3 shall not be recirculated. Air in excess of that required 
by Section 403.3 shall not be prohibited from being 
recirculated as a component of supply air to building spaces, 
except that: 

1. Ventilation air shall not be recirculated from one 
dwelling unit to another or to dissimilar occupancies. 

2. Supply air to a swinuning pool and associated deck 
areas shall not be recirculated unless such air is dehu- 
midified to maintain the relative humidity of the area 
at 60 percent or less. Air from this area shall not be 
recirculated to other spaces. 

3. Where mechanical exhaust is required by Table 
403.3, recirculation of air from such spaces shall be 
prohibited. All air supplied to such spaces shall be ex- 
hausted, including any air in excess of that required 
by Table 403.3. 



403.2.2 Transfer air. Except where recirculation from such 
spaces is prohibited by Table 403.3, air transferred from oc- 
cupied spaces is not prohibited from serving as makeup air 
for required exhaust systems in such spaces as kitchens, 
baths, toilet rooms, elevators and smoking lounges. The 
amount of transfer air and exhaust air shall be sufficient to 
provide the flow rates as specified in Sections 403.3 and 
403.3.1. The required outdoor air rates specified in Table 
403.3 shall be introduced directly into such spaces or into the 
occupied spaces from which air is transferred or a combina- 
tion of both. 

403.3 Ventilation rate. Ventilation systems shall be designed 
to have the capacity to supply the minimum outdoor airflow 
rate determined in accordance with Table 403.3 based on the 
occupancy of the space and the occupant load or other parame- 
ter as stated therein. The occupant load utilized for design of the 
ventilation system shall not be less than the number determined 
from the estimated maximum occupant load rate indicated in 
Table 403.3. Ventilation rates for occupancies not represented 
in Table 403.3 shall be determined by an approved engineering 
analysis. The ventilation system shall be designed to supply the 
required rate of ventilation air continuously during the period 
the building is occupied, except as otherwise stated in other 
provisions of the code. 

Exception: The occupant load is not required to be deter- 
mined, based on the estimated maximum occupant load rate 
indicated in Table 403.3 where approved statistical data 
document the accuracy of an alternate anticipated occupant 
density. 

403.3.1 System operation. The minimum flow rate of out- 
door air that the ventilation system must be capable of sup- 
plying during its operation shall be permitted to be based on 
the rate per person indicated in Table 403.3 and the actual 
number of occupants present. 

403.3.2 Common ventilation system. Where spaces hav- 
ing different ventilation rate requirements are served by a 
common ventilation system, the ratio of outdoor air to total 
supply air for the system shall be determined based on the 
space having the largest outdoor air requirement or shall be 
determined in accordance with the following formula: 

X 
Y = 7 ^ (Equation 4-1) 

(i + x-z) 

where 

Y= Vot^st = Corrected fraction of outdoor air in system 
supply. 

X= Von^st - Uncorrected fraction of outdoor air in sys- 
tem supply. 

Z = V^^ /V^^ = Fraction of outdoor air in critical space. The 
critical space is that space with the greatest 
required fraction of outdoor air in the supply 
to this space. 

V^t = Corrected total outdoor airflow rate. 

V^i = Total supply flow rate, i.e., the sum of all supply for 
all branches of the system. 

Vo„ = Sum of outdoor airflow rates for all branches on sys- 
tem. 



28 



2003 INTERNATIONAL MECHANICAL CODE® 



VENTILATION 



V^^ = Outdoor airflow rate required in critical spaces. 
V^^ = Supply flow rate in critical space. 

403.3.3 Variable air volume system control. Variable air 
volume air distribution systems, other than those designed 
to supply only 100-percent outdoor air, shall be provided 
with controls to regulate the flow of outdoor air. Such con- 
trol system shall be designed to maintain the flow of outdoor 
air at a rate of not less than that required by Section 403 over 
the entire range of supply air operating rates. 

403.3.4 Balancing. Ventilation systems shall be balanced 
by an approved method. Such balancing shall verify that the 
ventilation system is capable of supplying the airflow rates 
required by Section 403. 



SECTION 404 
ENCLOSED PARKING GARAGES 

404.1 Enclosed parking garages. Mechanical ventilation sys- 
tems for enclosed parking garages are not required to operate 
continuously where the system is arranged to operate automati- 
cally upon detection of a concentration of carbon monoxide of 
25 parts per million (ppm) by approved automatic detection de- 
vices. 

404.2 Minimum ventilation. Automatic operation of the sys- 
tem shall not reduce the ventilation rate below 0.05 cfm per 
square foot (0.00025 mVs • m^) of the floor area and the system 
shall be capable of producing a ventilation rate of 1.5 cfm per 
square foot (0.0076mVs • m^) of floor area. 

404.3 Occupied spaces accessory to public garages. Con- 
necting offices, waiting rooms, ticket booths and similar uses 
that are accessory to a public garage shall be maintained at a 
positive pressure and shall be provided with ventilation in ac- 
cordance with Section 403.3. 



SECTION 405 
SYSTEMS CONTROL 

405.1 General. Mechanical ventilation systems shall be pro- 
vided with manual or automatic controls that will operate such 
systems whenever the spaces are occupied. Air-conditioning 
systems that supply required ventilation air shall be provided 
with controls designed to automatically maintain the required 
outdoor air supply rate during occupancy. 



SECTION 406 
VENTILATION OF UNINHABITED SPACES 

406.1 General. Uninhabited spaces, such as crawl spaces and 
attics, shall be provided with natural ventilation openings as re- 
quired by the International Building Code or shall be provided 
with a mechanical exhaust and supply air system. The mechan- 
ical exhaust rate shall be not less than 0.02 cfm per square foot 
(0.00001 mVs . m^) of horizontal area and shall be automati- 
cally controlled to operate when the relative humidity in the 
space served exceeds 60 percent. 



TABLE 403.3 
REQUIRED OUTDOOR VENTILATION AIR 





ESTIMATED 






MAXIMUM 


OUTDOOR AIR 




OCCUPANT 


(Cubic feet per 




LOAD, PERSONS 


minute (cfm) 




PER 1,000 


per person) 


OCCUPANCY CLASSIFICATION 


SQUARE FEET^ 


UNLESS NOTED^ 


Correctional facilities 






Cells 






without plumbing fixtures 


20 


20 


with plumbing fixtures"^ 


20 


20 


Dining halls 


100 


15 


Guard stations 


40 


15 


Dry cleaners, laundries 






Coin-operated dry cleaner 


20 


15 


Coin-operated laundries 


20 


15 


Commercial dry cleaner 


30 


30 


Commercial laundry 


10 


25 


Storage, pick up 


30 


35 


Education 






Auditoriums 


150 


15 


Classrooms 


50 


15 


Corridors 


— 


O.lOcfm/ft' 


Laboratories 


30 


20 


Libraries 


20 


15 


Locker rooms'' 


— 


0.50 cfm/ft' 


Music rooms 


50 


15 


Smoking lounges'''* 


70 


60 


Training shops 


30 


20 


Food and beverage service 






Bars, cocktail lounges 


100 


30 


Cafeteria, fast food 


100 


20 


Dining rooms 


70 


20 


Kitchens (cooking)^'* 


20 


15 


Hospitals, nursing and 






convalescent homes 






Autopsy rooms" 


— 


0.50 cfm/ft' 


Medical procedure rooms 


20 


15 


Operating rooms 


20 


30 


Patient rooms 


10 


25 


Physical therapy 


20 


15 


Recovery and ICU 


20 


15 


Hotels, motels, resorts and 






dormitories 






Assembly rooms 


120 


15 


Bathrooms''^ 


— 


35 cfm per room 


Bedrooms 


— 


30 cfm per room 


Conference rooms 


50 


20 


Dormitory sleeping areas 


20 


15 


Gambling casinos 


120 


30 


Living rooms 


— 


30 cfm per room 


Lobbies 


30 


15 


Offices 






Conference rooms 


50 


20 


Office spaces 


7 


20 


Reception areas 


60 


15 


Telecommunication centers 






and data entry 


60 


20 



(continued) 



2003 INTERNATIONAL MECHANICAL CODE® 



29 



VENTILATION 



TABLE 403.3— continued 
REQUIRED OUTDOOR VENTILATION AIR 





ESTIMATED 






MAXIMUM 


OUTDOOR AIR 




OCCUPANT 


(Cubic feet per 




LOAD, PERSONS 


minute (cfm) 




PER 1,000 


per person) 


OCCUPANCY CLASSIFICATION 


SQUARE FEEr 


UNLESS NOTED^ 


Private dwellings, single and 






multiple 






Garages, common for 


— 


l.Scfm/ft' 


multiple units" 






Garages, separate for 
each dwelling 


__ 


100 cfm per car 


Kitchens' 




100 cfm 

intermittent or 25 

cfm continuous 


Living areas' 


Based upon 

number of 

bedrooms, first 


0.35 air changes 
per hour' or 15 cfm 




bedroom: 2; each 


per person. 




additional 


whichever is 




bedroom: 1 


greater 


Toilet rooms and 


— 


Mechanical 


bathrooms^ 




exhaust capacity of 

50 cfm intermittent 

or 20 cfm 

continuous 


Public spaces 






Corridors and utilities 


— 


0.05 cfm/ft' 


Elevators' 


— 


LOOcfm/ft' 


Locker rooms" 


— 


0.5 cfm/ft' 


Shower room 


— 


50 cfm 


(per shower head)"'^ 




intermittent or 20 
cfm continuous 


Smoking lounges''' 


70 


60 


Toilet rooms'' 


— 


75 cfm per water 
closet or urinal 


Retail stores, sales floors and 






showroom floors 






Basement and street 


— 


0.30 cfm/ft' 


Dressing rooms 


— 


0.20 cfm/ft' 


Malls and arcades 


— 


0.20 cfm/ft' 


Shipping and receiving 


— 


0.l5cfm/ft' 


Smoking lounges" 


70 


60 


Storage rooms 


— 


0.l5cfm/ft' 


Upper floors 


— 


0.20cfm/ft' 


Warehouses 


— 


0.05 cfm/ft' 


Specialty shops 






Automotive motor- 






fuel-dispensing stations 


— 


l.5cfm/ft' 


Barber 


25 


15 


Beauty 


25 


25 


Clothiers, furniture 


— 


0.30 cfm/ft' 


Florists 


8 


15 


Hardware, drugs, fabrics 


8 


15 


Nail salon" 


— 


25 


Pet shops 


— 


l.OOcfm/ft' 


Reducing salons 


20 


15 


Supermarkets 


8 


15 



TABLE 403.3— continued 




REQUIRED OUTDOOR VENTILATION AIR 




ESTIMATED 






MAXIMUM 


OUTDOOR AIR 




OCCUPANCY 


(Cubic feet per 




LOAD, PERSONS 


minute (cfm) 




PER 1,000 


per person) 


OCCUPANCY CLASSIFICATION 


SQUARE FEEr 


UNLESS NOTED^ 


Sports and amusement 






Ballrooms and discos 


100 


25 


Bowhng alleys (seating areas) 


70 


25 


Game rooms 


70 


25 


Ice arenas 


— 


0.50 cfm/ft' 


Playing floors (gymnasiums) 


30 


20 


Spectator areas 


150 


15 


Swimming pools (pool and deck 






area) 


— 


0.50 cfm/ft' 


Storage 






Repair garages, enclosed 






parking garages'* 


— 


1.5cfm/ft' 


' Warehouses 


— 


0.05 cfm/ft' 


Theaters 






Auditoriums 


150 


15 


Lobbies 


150 


20 


Stages, studios 


70 


15 


Ticket booths 


60 


20 


Transportation 






Platforms 


100 


15 


Vehicles 


150 


15 


Waiting rooms 


100 


15 


Workrooms 






Bank vaults 


5 


15 


Darkrooms 


— 


0.50 cfm/ft' 


Duplicating, printing 


— 


0.50cfm/ft' 


Meat processing' 


10 


15 


Pharmacy 


20 


15 


Photo studios 


10 


15 



► m^), 



For SI: 1 cubic foot per minute = 0.0004719 m^/s, 1 ton = 908 kg, 
1 cubic foot per minute per square foot = 0.00508 m^/(s * 
°C = [(°F) -32]/1.8, 1 square foot = 0.0929 m^. 

a. Based upon net floor area. 

b. Mechanical exhaust required and the recirculation of air from such spaces as 
permitted by Section 403.2.1 is prohibited (see Section 403.2.1). 

c. Spaces unheated or maintained below 50°F are not covered by these re- 
quirements unless the occupancy is continuous. 

d. Ventilation systems in enclosed parking garages shall comply with Sec- 
tion 404. A mechanical ventilation system shall not be required in garages 
having a floor area not exceeding 850 square feet and used for the storage 
of not more than four vehicles or trucks of 1 ton maximum capacity. 

e. Where the ventilation rate is expressed in cfm/ft^, such rate is based upon 
cubic feet per minute per square foot of the floor area being ventilated. 

f. The sum of the outdoor and transfer air from adjacent spaces shall be suffi- 
cient to provide an exhaust rate of not less than 1.5 cfm/ft^. 

g. Transfer air permitted in accordance with Section 403.2.2. 



(continued) 



30 



2003 INTERNATIONAL MECHANICAL CODE® 



CHAPTER 5 

EXHAUST SYSTEMS 



SECTION 501 
GENERAL 

501.1 Scope. This chapter shall govern the design, construction 
and installation of mechanical exhaust systems, including dust, 
stock and refuse conveyor systems, exhaust systems serving 
commercial cooking appliances and energy recovery ventila- 
tion systems. 

501.2 Outdoor discharge. The air removed by every mechani- 
cal exhaust system shall be discharged outdoors at a point 
where it will not cause a nuisance and from which it cannot 
again be readily drawn in by a ventilating system. Air shall not 
be exhausted into an attic or crawl space. 

Exceptions: 

1. Whole-house ventilation-type attic fans that dis- 
charge into the attic space of dwelling units having 
private attics. 

2. Commercial cooking recirculating systems. 

501.3 Pressure equalization. Mechanical exhaust systems shall 
be sized to remove the quantity of air required by this chapter to 
be exhausted. The system shall operate when air is required to be 
exhausted. Where mechanical exhaust is required in a room or 
space in other than occupancies in Group R-3, such space shall 
be maintained with a neutral or negative pressure. If a greater 
quantity of air is supplied by a mechanical ventilating supply 
system than is removed by a mechanical exhaust system for a 
room, adequate means shall be provided for the natural exit of 
the excess air supplied. If only a mechanical exhaust system is 
installed for a room or if a greater quantity of air is removed by a 
mechanical exhaust system than is supplied by a mechanical 
ventilating supply system for a room, adequate means shall be 
provided for the natural supply of the deficiency in the air sup- 
pUed. 

501.4 Ducts. Where exhaust duct construction is not specified 
in this chapter, such construction shall comply with Chapter 6. 



SECTION 502 
REQUIRED SYSTEMS 

502.1 General. An exhaust system shall be provided, main- 
tained and operated as specifically required by this section and 
for all occupied areas where machines, vats, tanks, furnaces, 
forges, salamanders and other appliances, equipment and pro- 
cesses in such areas produce or throw off dust or particles suffi- 
ciently light to float in the air, or which emit heat, odors, fumes, 
spray, gas or smoke, in such quantities so as to be irritating or 
injurious to health or safety. 

502.1.1 Exhaust location. The inlet to an exhaust system 
shall be located in the area of heaviest concentration of con- 
taminants. 



[F] 502.1.2 Fuel-dispensing areas. The bottom of an air in- 
let or exhaust opening in fuel-dispensing areas shall be lo- 
cated not more than 18 inches (457 mm) above the floor. 

502.1.3 Equipment, appliance and service rooms. Equip- 
ment, appliance and system service rooms that house 
sources of odors, fumes, noxious gases, smoke, steam, dust, 
spray or other contaminants shall be designed and con- 
structed so as to prevent spreading of such contaminants to 
other occupied parts of the building. 

[F] 502.1.4 Hazardous exhaust. The mechanical exhaust 
of high concentrations of dust or hazardous vapors shall 
conform to the requirements of Section 510. 

[F] 502.2 Aircraft fueling and defueling. Compartments 
housing piping, pumps, air eliminators, water separators, hose 
reels and similar equipment used in aircraft fueling and 
defueling operations shall be adequately ventilated at floor 
level or within the floor itself. 

[F] 502.3 Battery-charging areas. Ventilation shall be pro- 
vided in an approved manner in battery-charging areas to pre- 
vent a dangerous accumulation of flammable gases. 

[F] 502.4 Stationary lead-acid battery systems. Vendlation 
shall be provided for stationary lead-acid battery systems in ac- 
cordance with this chapter and Section 502.4.1 or 502.4.2. 

[F] 502.4.1 Hydrogen limit. The ventilation system shall 
be designed to limit the maximum concentration of hydro- 
gen to 1.0 percent of the total volume of the room. 

[F] 502.4.2 Ventilation rate. Continuous ventilation shall 
be provided at a rate of not less than 1 cubic foot per minute 
per square foot (cfm/ft^) [0.00508 mV(s • m^)] of floor area 
of the room. 

[F] 502.5 Valve-regulated lead-acid batteries. Valve-regu- 
lated lead-acid battery systems as regulated by Section 609 of 
the International Fire Code, shall be provided with ventilation 
in accordance with Section 502.5. 1 or 502.5.2 for rooms and in 
accordance with Section 502.5.3 or 502.5.4 for cabinets. 

[F] 502.5.1 Hydrogen limit in rooms. The ventilation sys- 
tem shall be designed to limit the maximum concentration 
of hydrogen to 1.0 percent of the total volume of the room 
during the worst-case event of simultaneous boost charging 
of all batteries in the room. 

[F] 502.5.2 Ventilation rate in rooms. Continuous ventila- 
tion shall be provided at a rate of not less than 1 cubic foot 
per minute per square foot (cfm/ft.^) [0.00508 mV(s*m^)] of 
floor area of the room. 

[F] 502.5.3 Hydrogen limit in cabinets. The ventilation 
system shall be designed to limit the maximum concentra- 
tion of hydrogen to 1.0 percent of the total volume of the 
cabinet during the worst-case event of simultaneous boost 
charging of all batteries in the cabinet. 



2003 INTERNATIONAL MECHANICAL CODE® 



31 



EXHAUST SYSTEMS 



[F] 502.5.4 Ventilation rate in cabinets. Continuous venti- 
lation shall be provided at a rate of not less than 1 cubic foot 
per minute per square foot (cfm/ft.^) [0.00508 mV(s«m^)] of 
the floor area covered by the cabinet. The room in which the 
cabinet is installed shall also be ventilated as required by 
Section 502.5.1 or 502.5.2. 

[F] 502.6 Dry cleaning plants. Ventilation in dry cleaning 
plants shall be adequate to protect employees and the public in 
accordance with this section and DOL 29 CFR Part 1910.1000, 
where applicable. 

[F] 502.6.1 Type II systems. Type II dry cleaning systems 
shall be provided with a mechanical ventilation system that 
is designed to exhaust 1 cubic foot of air per minute for each 
square foot of floor area (1 cfm/ft^) [0.00508 mV(s • m^)] in 
dry cleaning rooms and in drying rooms. The ventilation 
system shall operate automatically when the dry cleaning 
equipment is in operation and shall have manual controls at 
an approved location. 

[F] 502.6.2 Type IV and V systems. Type IV and V dry 
cleaning systems shall be provided with an automatically 
activated exhaust ventilation system to maintain a minimum 
of 100 feet per minute (0.5 m/s) air velocity through the 
loading door when the door is opened. 

Exception: Dry cleaning units are not required to be pro- 
vided with exhaust ventilation where an exhaust hood is 
installed immediately outside of and above the loading 
door which operates at an airflow rate as follows: 



G=100xA,^ 

where: 

Q 



(Equation 5-1) 



= Flow rate exhausted through the hood, cubic feet 
per minute. 

Ai^ = Area of the loading door, square feet. 

[F] 502.6.3 Spotting and pretreating. Scrubbing tubs, 
scouring, brushing or spotting operations shall be located 
such that solvent vapors are captured and exhausted by the 
ventilating system. 

[F] 502.7 Application of flammable finishes. Mechanical ex- 
haust as required by this section shall be provided for opera- 
tions involving the application of flammable finishes. 

[F] 502.7.1 During construction. Ventilation shall be pro- 
vided for operations involving the application of materials 
containing flammable solvents in the course of construc- 
tion, alteration or demolition of a structure. 

[F] 502.7.2 Limited spraying spaces. Positive mechanical 
ventilation which provides a minimum of six complete air 
changes per hour shall be installed in hmited spraying 
spaces. Such system shall meet the requirements of the In- 
ternational Fire Code for handling flammable vapors. Ex- 
plosion venting is not required. 

[F] 502.7.3 Spraying areas. Mechanical ventilation of 
spraying areas shall be provided in accordance with Sec- 
tions 502.7.3.1 through 502.7.3.7. 

[Fl 502.7.3.1 Operation. Mechanical ventilation shall 
be kept in operation at all times while spraying opera- 
tions are being conducted and for a sufficient time there- 



after to allow vapors from drying coated articles and fin- 
ishing material residue to be exhausted. Spraying equip- 
ment shall be interlocked with the ventilation of the 
spraying area such that spraying operations cannot be 
conducted unless the ventilation system is in operation. 

[Fl 502.7.3.2 Recirculation. Air exhausted from spray- 
ing operations shall not be recirculated. 

Exceptions: 

1 . Air exhausted from spraying operations shall be 
permitted to be recirculated as makeup air for 
unmanned spray operations provided that: 

1.1. Solid particulate has been removed. 

1.2. The vapor concentration is less than 25 
percent of the lower flammable limit 
(LFL). 

1.3. Approved equipment is used to monitor 
the vapor concentration. 

L4. An alarm is sounded and spray opera- 
tions are automatically shut down if the 
vapor concentration exceeds 25 percent 
of the LFL. 

1.5. The spray booths, spray spaces or spray 
rooms involved in any recirculation pro- 
cess shall be provided with mechanical 
ventilation that shall automatically ex- 
haust 100 percent of the required air 
volume in the event of shutdown by ap- 
proved equipment used to monitor va- 
por concentrations. 

2. Air exhausted from spraying operations shall be 
permitted to be recirculated as makeup air to 
manned spraying operations if all of the condi- 
tions provided in Exception 1 are included in 
the installation and documents have been pre- 
pared to show that the installation does not pres- 
ent life safety hazards to personnel inside the 
spray booth, spray space or spray room. 

[Fl 502.7.3.3 Air velocity. Ventilation systems shall be 
designed, installed and maintained such that the average 
air velocity over the open face of the booth, or booth cross 
section in the direction of airflow during spraying opera- 
tions, is not less than 100 feet per minute (0.51 m/s). 

[Fl 502.7.3.4 Ventilation obstruction. Articles being 
sprayed shall be positioned in a manner that does not ob- 
struct collection of overspray. 

[F] 502.7.3.5 Independent ducts. Each spray booth and 
spray room shall have an independent exhaust duct sys- 
tem discharging to the outdoors. 

Exceptions: 

1 . Multiple spray booths having a combined fron- 
tal area of 1 8 square feet ( 1 .67 m ) or less are al- 
lowed to have a common exhaust where 
identical spray-fmishing material is used in 
each booth. If more than one fan serves one 



32 



2003 INTERNATIONAL MECHANICAL CODE® 



EXHAUST SYSTEMS 



booth, such fans shall be interconnected so that 
all fans operate simultaneously. 
2. Where treatment of exhaust is necessary for air 
pollution control or energy conservation, ducts 
shall be allowed to be manifolded if all of the 
following conditions are met: 

2.1. The sprayed materials used are compat- 
ible and will not react or cause ignition 
of the residue in the ducts. 

2.2. Nitrocellulose-based finishing material 
shall not be used. 

2.3. A filtering system shall be provided to 
reduce the amount of overspray carried 
into the duct manifold. 

2.4. Automatic sprinkler protection shall be 
provided at the junction of each booth 
exhaust with the manifold, in addition to 
the protection required by this chapter. 

[F] 502.7.3.6 Termination point. The termination point 
for exhaust ducts discharging to the atmosphere shall be 
located with the following minimum distances. 

1. For ducts conveying explosive or flammable va- 
pors, fumes or dusts: 30 feet (9144 mm) from the 
property line; 10 feet (3048 mm) from openings 
into the building; 6 feet (1829 mm) from exterior 
walls and roofs; 30 feet (9144 mm) from combusti- 
ble walls and openings into the building which are 
in the direction of the exhaust discharge; 10 feet 
(3048 mm) above adjoining grade. 

2. For other product-conveying outlets: 10 feet (3048 
nmi) from the property line; 3 feet (914 mm) from 
exterior walls and roofs; 10 feet (3048 mm) from 
openings into the building; 10 feet (3048 mm) 
above adjoining grade. 

3. For environmental air duct exhaust: 3 feet (914 
mm) from the property line; 3 feet (914 mm) from 
openings into the building. 

[F] 502.7.3.7 Fan motors and belts. Electric motors 
driving exhaust fans shall not be placed inside booths or 
ducts. Fan rotating elements shall be nonferrous or 
nonsparking or the casing shall consist of, or be lined 
with, such material. Belts shall not enter the duct or booth 
unless the belt and pulley within the duct are tightly en- 
closed. 

[F] 502.7.4 Dipping operations. Vapor areas of dip tank 
operations shall be provided with mechanical ventilation 
adequate to prevent the dangerous accumulation of vapors. 
Required ventilation systems shall be so arranged that the 
failure of any ventilating fan will automatically stop the dip- 
ping conveyor system. 

[F] 502.7.5 Electrostatic apparatus. The spraying area in 
spray-finishing operations involving electrostatic apparatus 
and devices shall be ventilated in accordance with Section 
502.7.3. 

[F] 502.7.6 Powder coating. Exhaust ventilation for pow- 
der-coating operations shall be sufficient to maintain the at- 



mosphere below one-half of the minimum explosive concen- 
tration for the material being applied. Nondeposited, air-sus- 
pended powders shall be removed through exhaust ducts to 
the powder recovery cyclone or receptacle. 

[F] 502.7.7 Floor resurfacing operations. To prevent the 
accumulation of flammable vapors during floor resurfacing 
operations, mechanical ventilation at a minimum rate of 1 
cfm/ft^ [0.00508 mV(s . m^)] of area being finished shall be 
provided. Such exhaust shall be by approved temporary or 
portable means. Vapors shall be exhausted to the exterior of 
the building. 

[F] 502.8 Hazardous materials — general requirements. Ex- 
haust ventilation systems for structures containing hazardous 
materials shall be provided as required in Sections 502.8.1 
through 502.8.5. 

[F] 502.8.1 Storage in excess of the maximum allowable 
quantities. Indoor storage areas and storage buildings for 
hazardous materials in amounts exceeding the maximum al- 
lowable quantity per control area shall be provided with me- 
chanical exhaust ventilation or natural ventilation where 
natural ventilation can be shown to be acceptable for the ma- 
terials as stored. 

Exception: Storage areas for flammable solids comply- 
ing with the International Fire Code. 

[F] 502.8.1.1 System requirements. Exhaust ventila- 
tion systems shall comply with all of the following: 

1. The installation shall be in accordance with this 
code. 

2. Mechanical ventilation shall be provided at a rate 
of not less than 1 cfm/ft^ [0.00508 m^/(s • m^)] of 
floor area over the storage area. 

3. The systems shall operate continuously unless al- 
ternate designs are approved. 

4. A manual shutoff control shall be provided outside 
of the room in a position adjacent to the access 
door to the room or in another approved location. 
The switch shall be of the break-glass type and 
shall be labeled: VENTILATION SYSTEM 
EMERGENCY SHUTOFF. 

5. The exhaust ventilation system shall be designed 
to consider the density of the potential fumes or va- 
pors released. For fumes or vapors that are heavier 
than air, exhaust shall be taken from a point within 
12 inches (304 mm) of the floor. I 

6. The location of both the exhaust and inlet air open- 
ings shall be designed to provide air movement 
across all portions of the floor or room to prevent 
the accumulation of vapors. 

7. The exhaust ventilation shall not be recirculated 
within the room or building if the materials stored 
are capable of emitting hazardous vapors. 

[F] 502.8.2 Gas rooms, exhausted enclosures and gas 
cabinets. The ventilation system for gas rooms, exhausted 
enclosures and gas cabinets for any quantity of hazardous 
material shall be designed to operate at a negative pressure 
in relation to the surrounding area. Highly toxic and toxic 



2003 INTERNATIONAL MECHANICAL CODE® 



33 



EXHAUST SYSTEMS 



gases shall also comply with Sections 502.9.7.1, 502.9.7.2 
and 502.9.8.4. 

[F] 502.8.3 Indoor dispensing and use. Indoor dispensing 
and use areas for hazardous materials in amounts exceeding 
the maximum allowable quantity per control area shall be 
provided with exhaust ventilation in accordance with Sec- 
tion 502.7.1. 

Exception: Ventilation is not required for dispensing 
and use of flammable solids other than finely divided 
particles. 

[F] 502.8.4 Indoor dispensing and use — point sources. 

Where gases, hquids or sohds in amounts exceeding the maxi- 
mum allowable quantity per control area and having a hazard 
ranking of 3 or 4 in accordance with NFPA 704 are dispensed 
or used, mechanical exhaust ventilation shall be provided to 
capture fumes, mists or vapors at the point of generation. 

Exception: Where it can be demonstrated that the gases, 
liquids or solids do not create harmful fumes, mists or va- 
pors. 

[F] 502.8.5 Closed systems. Where closed systems for the 
use of hazardous materials in amounts exceeding the maxi- 
mum allowable quantity per control area are designed to be 
opened as part of normal operations, ventilation shall be 
provided in accordance with Section 502.8.4. 

[F] 502.9 Hazardous materials — requirements for specific 
materials. Exhaust ventilation systems for specific hazardous 
materials shall be provided as required in Section 502.8 and 
Sections 502.9.1 through 502.9.11. 

[F] 502.9.1 Compressed gases — medical gas systems. 

Rooms for the storage of compressed medical gases in 
amounts exceeding the maximum allowable exempt quan- 
tity per control area, and which do not have an exterior wall, 
shall be exhausted through a duct to the exterior of the build- 
ing. Both separate airstreams shall be enclosed in a 
1 -hour-rated shaft enclosure from the room to the exterior. 
Approved mechanical ventilation shall be provided at a 
minimum rate of 1 cfm/ft^ [0.00508 mV(s . m^)] of the area 
of the room. 

Gas cabinets for the storage of compressed medical gases 
in amounts exceeding the maximum allowable quantity per 
control area shall be connected to an exhaust system. The av- 
erage velocity of ventilation at the face of access ports or win- 
dows shall be not less than 200 feet per minute (1.02 m/s) 
with a minimum velocity of 150 feet per minute (0.76 m/s) at 
any point at the access port or window. 

[F] 502.9.2 Corrosives. Where corrosive materials in 
amounts exceeding the maximum allowable quantity per 
control area are dispensed or used, mechanical exhaust venti- 
lation in accordance with Section 502.8.4 shall be provided. 

[F] 502.9.3 Cryogenics. Storage areas for stationary or por- 
table containers of cryogenic fluids in any quantity shall be 
ventilated in accordance with Section 502.8. Indoor areas 
where cryogenic fluids in any quantity are dispensed shall 
be ventilated in accordance with the requirements of Sec- 
tion 502.8.4 in a manner that captures any vapor at the point 
of generation. 



Exception: Ventilation for indoor dispensing areas is not 
required where it can be demonstrated that the cryogenic 
fluids do not create harmful vapors. 

[F] 502.9.4 Explosives. Squirrel cage blowers shall not be 
used for exhausting hazardous fumes, vapors or gases in op- 
erating buildings and rooms for the manufacture, assembly 
or testing of explosives. Only nonferrous fan blades shall be 
used for fans located within the ductwork and through 
which hazardous materials are exhausted. Motors shall be 
located outside the duct. 

[F] 502.9.5 Flammable and combustible liquids. Exhaust 
ventilation systems shall be provided as required by Sec- 
tions 502.9.5.1 through 502.9.5.5 for the storage, use, dis- 
pensing, mixing and handling of flammable and 
combustible liquids. Unless otherwise specified, this sec- 
tion shall apply to any quantity of flammable and combusti- 
ble liquids. 

Exception: This section shall not apply to flammable 
and combustible liquids that are exempt from the Inter- 
national Fire Code. 

[F] 502.9.5.1 Vaults. Vaults that contain tanks of Class I 
liquids shall be provided with continuous ventilation at a 
rate of not less than 1 cfm/ft^ of floor area [0.00508 m^/(s . 
m )], but not less than 150 cfm (4 m /min). Failure of the 
exhaust airflow shall automatically shut down the dispens- 
ing system. The exhaust system shall be designed to pro- 
vide air movement across all parts of the vault floor. 
Supply and exhaust ducts shall extend to a point not 
greater than 12 inches (305 mm) and not less than 3 inches 
(76 mm) above the floor. The exhaust system shall be in- 
stalled in accordance with the provisions of NFPA 91. 
Means shall be provided to automatically detect any flam- 
mable vapors and to automatically shut down the dispens- 
ing system upon detection of such flanmiable vapors in the 
exhaust duct at a concentration of 25 percent of the LFL. 

[F] 502.9.5.2 Storage rooms and vt^arehouses. Liquid 
storage rooms and liquid storage warehouses for quanti- 
ties of liquids exceeding those specified in the Interna- 
tional Fire Code shall be ventilated in accordance with 
Section 502.8.1. 

[F] 502.9.5.3 Cleaning machines. Areas containing ma- 
chines used for parts cleaning in accordance with the In- 
ternational Fire Code shall be adequately ventilated to 
prevent accumulation of vapors. 

[F] 502.9.5.4 Use, dispensing and mixing. Continuous 
mechanical ventilation shall be provided for the use, dis- 
pensing and mixing of flammable and combustible liquids 
in open or closed systems in amounts exceeding the maxi- 
mum allowable quantity per control area and for bulk trans- 
fer and process transfer operations. The ventilation rate 
shaU be not less than 1 cfm/ft^ [0.00508 m^/(s . m^)] of floor 
area over the design area. Provisions shall be made for the 
introduction of makeup air in a manner that will include all 
floor areas or pits where vapors can collect. Local or spot 
ventilation shall be provided where needed to prevent the 
accumulation of hazardous vapors. 



34 



2003 INTERNATIONAL MECHANICAL CODE® 



EXHAUST SYSTEMS 



Exception: Where natural ventilation can be shown 
to be effective for the materials used, dispensed, or 
mixed. 

[F] 502.9.5.5 Bulk plants or terminals. Ventilation 
shall be provided for portions of properties where flam- 
mable and combustible liquids are received by tank ves- 
sels, pipelines, tank cars or tank vehicles and which are 
stored or blended in bulk for the purpose of distributing 
such liquids by tank vessels, pipelines, tank cars, tank ve- 
hicles or containers as required by Sections 502.9.5.5.1 
through 502.9.5.5.3. 

[F] 502.9.5.5.1 General. Ventilation shall be pro- 
vided for rooms, buildings and enclosures in which 
Class I liquids are pumped, used or transferred. De- 
sign of ventilation systems shall consider the rela- 
tively high specific gravity of the vapors. Where 
natural ventilation is used, adequate openings in out- 
side walls at floor level, unobstructed except by lou- 
vers or coarse screens, shall be provided. Where 
natural ventilation is inadequate, mechanical ventila- 
tion shall be provided. 

[F] 502.9.5.5.2 Basements and pits. Class I liquids 
shall not be stored or used within a building having a 
basement or pit into which flammable vapors can 
travel, unless such area is provided with ventilation de- 
signed to prevent the accumulation of flammable va- 
pors therein. 

[F] 502.9.5.5.3 Dispensing of Class I liquids. Con- 
tainers of Class I liquids shall not be drawn from or 
filled within buildings unless a provision is made to 
prevent the accumulation of flammable vapors in haz- 
ardous concentrations. Where mechanical ventilation 
is required, it shall be kept in operation while flamma- 
ble vapors could be present. 

[F] 502.9.6 Highly toxic and toxic liquids. Ventilation ex- 
haust shall be provided for highly toxic and toxic liquids as 
required by Sections 502.9.6.1 and 502.9.6.2. 

[F] 502.9.6.1 Treatment system. This provision shall 
apply to indoor and outdoor storage and use of highly 
toxic and toxic liquids in amounts exceeding the maxi- 
mum allowable quantities per control area. Exhaust 
scrubbers or other systems for processing vapors of 
highly toxic liquids shall be provided where a spill or ac- 
cidental release of such liquids can be expected to release 
highly toxic vapors at normal temperature and pressure. 

[F] 502.9.6.2 Open and closed systems. Mechanical ex- 
haust ventilation shall be provided for highly toxic and 
toxic liquids used in open systems in accordance with Sec- 
tion 502.8.4. Mechanical exhaust ventilation shall be pro- 
vided for highly toxic and toxic liquids used in closed 
systems in accordance with Section 502.8.5. 

Exception: Liquids or solids that do not generate 
highly toxic or toxic fumes, mists or vapors. 

[F] 502.9.7 Highly toxic and toxic compressed gases — 
any quantity. Ventilation exhaust shall be provided for 
highly toxic and toxic compressed gases in any quantity as 
required by Sections 502.9.7.1 and 502.9,7.2. 



[F] 502.9.7.1 Gas cabinets. Gas cabinets containing 
highly toxic or toxic compressed gases in any quantity 
shall comply with Section 502.8.2 and the following re- 
quirements: 

1. The average ventilation velocity at the face of gas 
cabinet access ports or windows shall be not less 
than 200 feet per minute (1.02 m/s) with a mini- 
mum velocity of 150 feet per minute (0.76 m/s) at 
any point at the access port or window. 

2. Gas cabinets shall be connected to an exhaust sys- 
tem. 

3. Gas cabinets shall not be used as the sole means of 
exhaust for any room or area. 

[F] 502.9.7.2 Exhausted enclosures. Exhausted enclo- 
sures containing highly toxic or toxic compressed gases 
in any quantity shall comply with Section 502.8.2 and the 
following requirements: 

1 . The average ventilation velocity at the face of the 
enclosure shall be not less than 200 feet per minute 
( 1 .02 m/s) with a minimum velocity of 1 50 feet per 
minute (0.76 m/s). 

2. Exhausted enclosures shall be connected to an ex- 
haust system. 

3. Exhausted enclosures shall not be used as the sole 
means of exhaust for any room or area. 

[F] 502.9.8 Highly toxic and toxic compressed gases — 
quantities exceeding the maximum allowable per con- 
trol area. Ventilation exhaust shall be provided for highly 
toxic and toxic compressed gases in amounts exceeding the 
maximum allowable quantities per control area as required 
by Sections 502.9.8.1 through 502.9.8.6. 

[F] 502.9.8.1 Ventilated areas. The room or area in 
which indoor gas cabinets or exhausted enclosures are 
located shall be provided with exhaust ventilation. Gas 
cabinets or exhausted enclosures shall not be used as the 
sole means of exhaust for any room or area. 

[F] 502.9.8.2 Local exhaust for portable tanks. A 

means of local exhaust shall be provided to capture leak- 
age from indoor and outdoor portable tanks. The local 
exhaust shall consist of portable ducts or collection sys- 
tems designed to be appUed to the site of a leak in a valve 
or fitting on the tank. The local exhaust system shall be 
located in a gas room. Exhaust shall be directed to a treat- 
ment system where required by the International Fire 
Code, 

[F] 502.9.8.3 Piping and controls — stationary tanks. 

Filling or dispensing connections on indoor stationary 
tanks shall be provided with a means of local exhaust. 
Such exhaust shall be designed to capture fumes and va- 
pors. The exhaust shall be directed to a treatment system 
where required by the International Fire Code. 

[F] 502.9.8.4 Gas rooms. The ventilation system for gas 
rooms shall be designed to operate at a negative pressure 
in relation to the surrounding area. The exhaust ventila- 
tion from gas rooms shall be directed to an exhaust sys- 
tem. 



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[F] 502.9.8.5 Treatment system. The exhaust ventila- 
tion from gas cabinets, exhausted enclosures and gas 
rooms, and local exhaust systems required in Sections 
502.9.8.2 and 502.9.8.3 shall be directed to a treatment 
system where required by the International Fire Code. 

[F] 502.9.8.6 Process equipment. Effluent from indoor 
and outdoor process equipment containing highly toxic 
or toxic compressed gases which could be discharged to 
the atmosphere shall be processed through an exhaust 
scrubber or other processing system. Such systems shall 
be in accordance with the International Fire Code. 

[F] 502.9.9 Ozone gas generators. Ozone cabinets and 
ozone gas-generator rooms for systems having a maximum 
ozone-generating capacity of one-half pound (0.23 kg) or 
more over a 24-hour period shall be mechanically ventilated 
at a rate of not less than six air changes per hour. For cabi- 
nets, the average velocity of ventilation at makeup air open- 
ings with cabinet doors closed shall be not less than 200 feet 
per minute ( 1 .02 m/s) . 

[F] 502.9.10 LP-gas distribution facilities. LP-gas distri- 
bution facilities shall be ventilated in accordance with 
NFPA 58. 

[F] 502.9.10.1 Portable container use. Above-grade 
underfloor spaces or basements in which portable 
LP-gas containers are used or are stored awaiting use or 
re-sale shall be provided with an approved means of ven- 
tilation. 

Exception: Department of Transportation (DOT) 
specification cylinders with a maximum water capac- 
ity of 2.5 pounds ( 1 kg) for use in completely self-con- 
tained hand torches and similar appHcations. The 
quantity of LP-gas shall not exceed 20 pounds (9 kg). 

[F] 502.9.11 Silane gas. Exhausted enclosures and gas cab- 
inets for the indoor storage of silane gas in amounts exceed- 
ing the maximum allowable quantities per control area shall 
comply with this section. 

L Exhausted enclosures and gas cabinets shall be in ac- 
cordance with Section 502.8.2. 

2. The velocity of ventilation across unwelded fittings 
and connections on the piping system shall not be less 
than 200 feet per minute (L02 m/s). 

3. The average velocity at the face of the access ports or 
windows in the gas cabinet shall not be less than 200 
feet per minute ( 1 .02 m/s) with a minimum velocity of 
150 feet per minute (0.76 m/s) at any point at the ac- 
cess port or window. 

[F] 502.10 Hazardous production materials (HPM). Ex- 
haust ventilation systems and materials for ducts utilized for 
the exhaust of HPM shall comply with this section, other appli- 
cable provisions of this code, the International Building Code 
and the International Fire Code. 

[F] 502.10.1 Where required. Exhaust ventilation systems 
shall be provided in the following locations in accordance 
with the requirements of this section and the International 
Building Code: 



1. Fabrication areas: Exhaust ventilation for fabrica- 
tion areas shall comply with the International 
Building Code. Additional manual control 
switches shall be provided where required by the 
code official. 

2. Workstations: A ventilation system shall be pro- 
vided to capture and exhaust fumes and vapors at 
workstations. 

3. Liquid storage rooms: Exhaust ventilation for liq- 
uid storage rooms shall comply with Section 
502.8.1.1 and the International Building Code. 

4. HPM rooms: Exhaust ventilation for HPM rooms 
shall comply with Section 502.8.1.1 and the Inter- 
national Building Code. 

5. Gas cabinets: Exhaust ventilation for gas cabinets 
shall comply with Section 502.8.2. The gas cabinet 
ventilation system is allowed to connect to a work- 
station ventilation system. Exhaust ventilation for 
gas cabinets containing highly toxic or toxic gases 
shall also comply with Sections 502.9.7 and 
502.9.8. 

6. Exhausted enclosures: Exhaust ventilation for ex- 
hausted enclosures shall comply with Section 
502.7.2. Exhaust ventilation for exhausted enclo- 
sures containing highly toxic or toxic gases shall 
also comply with Sections 502.9.7 and 502.9.8. 

7. Gas rooms: Exhaust ventilation for gas rooms shall 
comply with Section 502.8.2. Exhaust ventilation 
for gas cabinets containing highly toxic or toxic 
gases shall also comply with Sections 502.9.7 and 
502.9.8. 

[F] 502.10.2 Penetrations. Exhaust ducts penetrating fire 
barrier assemblies shall be contained in a shaft of equivalent 
fire-resistive construction. Exhaust ducts shall not penetrate 
building separation walls. Fire dampers shall not be in- 
stalled in exhaust ducts. 

[F] 502.10.3 Treatment systems. Treatment systems for 
highly toxic and toxic gases shall comply with the Interna- 
tional Fire Code, 

502.11 Motion picture projectors. Motion picture projectors 
shall be exhausted in accordance with Section 502.11.1 or 
502.11.2. 

502.11.1 Projectors v*^ith an exhaust discharge. Projec- 
tors equipped with an exhaust discharge shall be directly 
connected to a mechanical exhaust system. The exhaust sys- 
tem shall operate at an exhaust rate as indicated by the man- 
ufacturer's installation instructions. 

502.11.2 Projectors without exhaust connection. Projec- 
tors without an exhaust connection shall have contaminants 
exhausted through a mechanical exhaust system. The ex- 
haust rate for electric arc projectors shall be a minimum of 
200 cubic feet per minute (cfm) (0.09 mVs) per lamp. The 
exhaust rate for xenon projectors shall be a minimum of 300 
cfm (0.14 mVs) per lamp. Xenon projector exhaust shall be 
at a rate such that the exterior temperature of the lamp hous- 
ing does not exceed 130°F (54''C). The lamp and projection 
room exhaust systems, whether combined or independent, 



36 



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shall not be interconnected with any other exhaust or return 
system within the building. 

[F] 502.12 Organic coating processes. Enclosed structures in- 
volving organic coating processes in which Class I liquids are 
processed or handled shall be ventilated at a rate of not less than 
1 cfm/ft^ [0,00508 mV(s • m^)] of solid floor area. Ventilation 
shall be accomplished by exhaust fans that intake at floor levels 
and discharge to a safe location outside the structure. 
Noncontaminated intake air shall be introduced in such a man- 
ner that all portions of soUd floor areas are provided with con- 
tinuous uniformly distributed air movement. 

502.13 Public garages. Mechanical exhaust systems for public 
garages, as required in Chapter 4, shall operate continuously or 
in accordance with Section 404. 

502.14 Motor vehicle operation. In areas where motor vehi- 
cles operate, mechanical ventilation shall be provided in accor- 
dance with Section 403. Additionally, areas in which stationary 
motor vehicles are operated shall be provided with a source 
capture system that connects directly to the motor vehicle ex- 
haust systems. 

Exceptions: 

1 . This section shall not apply where the motor vehicles 
being operated or repaired are electrically powered. 

2. This section shall not apply to one- and two-family 
dwellings. 

3. This section shall not apply to motor vehicle service 
areas where engines are operated inside the building 
only for the duration necessary to move the motor ve- 
hicles in and out of the building. 

[F] 502.15 Repair garages. Where Class I liquids or LP-gas 
are stored or used within a building having a basement or pit 
wherein flammable vapors could accumulate, the basement or 
pit shall be provided with ventilation designed to prevent the 
accumulation of flammable vapors therein. 

[F] 502.16 Repair garages for natural gas- and hydro- 
gen-fueled vehicles. Repair garages used for the repair of natu- 
ral gas- or hydrogen-fueled vehicles shall be provided with an 
approved mechanical ventilation system. The mechanical ven- 
tilation system shall be in accordance with Sections 502.16.1 
and 502.16.2. 

Exception: Where approved by the code official, natural 
ventilation shall be permitted in lieu of mechanical ventila- 
tion. 

[F] 502.16.1 Design. Indoor locations shall be ventilated uti- 
hzing air supply inlets and exhaust outlets arranged to pro- 
vide uniform air movement to the extent practical. Inlets shall 
be uniformly arranged on exterior walls near floor level. Out- 
lets shall be located at the high point of the room in exterior 
walls or the roof. 

1 . Ventilation shall be by a continuous mechanical venti- 
lation system or by a mechanical ventilation system 
activated by a continuously monitoring natural gas 
detection system activating at a gas concentration of 
25 percent of the LFL. In all cases, the system shall 
shut down the fueling system in the event of failure of 
the ventilation system. 



2. The ventilation rate shall be at least 1 cubic foot per 
minute per 12 cubic feet [0.00138 mV(s • m^)] of room 
volume. 

[F] 502.16.2 Operation. The mechanical ventilation sys- 
tem shall operate continuously. 

Exceptions: 

1, Mechanical ventilation systems that are inter- 
locked with a gas detection system designed in ac- 
cordance with the International Fire Code. 

2. Mechanical ventilation systems in garages that are 
used only for the repair of vehicles fueled by liquid 
fuels or odorized gases, such as CNG, where the 
ventilation system is electrically interlocked with 
the lighting circuit. 

502.17 Tire rebuilding or recapping. Each room where rub- 
ber cement is used or mixed, or where flammable or combusti- 
ble solvents are applied, shall be ventilated in accordance with 
the applicable provisions of NFPA 91. 

502.17.1 Buffing machines. Each buffmg machine shall be 
connected to a dust-collecting system that prevents the ac- 
cumulation of the dust produced by the buffing process. 

502.18 Specific rooms. Specific rooms, including bathrooms, 
locker rooms, smoking lounges and toilet rooms, shall be ex- 
hausted in accordance with the ventilation requirements of 
Chapter 4. 

SECTION 503 
MOTORS AND FANS 

503.1 General. Motors and fans shall be sized to provide the 
required air movement. Motors in areas that contain flammable 
vapors or dusts shall be of a type approved for such environ- 
ments. A manually operated remote control installed at an ap- 
proved location shall be provided to shut off fans or blowers in 
flammable vapor or dust systems. Electrical equipment and ap- 
pliances used in operations that generate explosive or flanmia- 
ble vapors, fumes or dusts shall be interlocked with the 
ventilation system so that the equipment and appliances cannot 
be operated unless the ventilation fans are in operation. Motors 
for fans used to convey flammable vapors or dusts shall be lo- 
cated outside the duct or shall be protected with approved 
shields and dustproofmg. Motors and fans shall be provided 
with a means of access for servicing and maintenance. 

503.2 Fans. Parts of fans in contact with explosive or flammable 
vapors, fumes or dusts shall be of nonferrous or nonsparking ma- 
terials, or their casing shall be hned or constructed of such mate- 
rial. When the size and hardness of materials passing through a 
fan are capable of producing a spark, both the fan and the casing 
shall be of nonsparking materials. When fans are required to be 
spark resistant, their bearings shall not be within the airstream, 
and all parts of the fan shall be grounded. Fans in systems-han- 
dHng materials that are capable of clogging the blades, and fans 
in buffing or woodworking exhaust systems, shall be of the ra- 
dial-blade or tube-axial type. 

503.3 Equipment and appliances identification plate. 

Equipment and appliances used to exhaust explosive or flam- 
mable vapors, fumes or dusts shall bear an identification plate 
stating the ventilation rate for which the system was designed. 



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503.4 Corrosion-resistant fans. Fans located in systems con- 
veying corrosives shall be of materials that are resistant to the 
corrosive or shall be coated with corrosion-resistant materials. 



SECTION 504 
CLOTHES DRYER EXHAUST 

504.1 Installation. Clothes dryers shall be exhausted in accor- 
dance with the manufacturer's instructions. Dryer exhaust sys- 
tems shall be independent of all other systems and shall convey 
the moisture and any products of combustion to the outside of 
the building. 

■ Exception: This section shall not apply to listed and labeled 
condensing (ductless) clothes dryers. 

504.2 Exhaust penetrations. Ducts that exhaust clothes dryers 
shall not penetrate or be located within any fireblocking, 
draftstopping or any wall, floor/ceiling or other assembly re- 
quired by the International Building Code to be fire-resistance 
rated, unless such duct is constructed of galvanized steel or alu- 
minum of the thickness specified in Section 603.4 and the 
fire-resistance rating is maintained in accordance with the Inter- 

I national Building Code, Fire dampers, combination fire/smoke 
dampers and any similar devices that will obstruct the exhaust 
flow, shall be prohibited in clothes dryer exhaust ducts. 

504.3 Cleanout. Each vertical riser shall be provided with a 
means for cleanout. 

504.4 Exhaust installation. Dryer exhaust ducts for clothes 
dryers shall terminate on the outside of the building and shall be 
equipped with a backdraft damper. Screens shall not be in- 
stalled at the duct termination. Ducts shall not be connected or 
installed with sheet metal screws or other fasteners that will ob- 
struct the exhaust flow. Clothes dryer exhaust ducts shall not be 
connected to a vent connector, vent or chimney. Clothes dryer 
exhaust ducts shall not extend into or through ducts or plenums. 

504.5 Makeup air. Installations exhausting more than 200 cfm 
(0.09 mVs) shall be provided with makeup air. Where a closet is 
designed for the installation of a clothes dryer, an opening hav- 
ing an area of not less than 100 square inches (0.0645 m^) shall 
be provided in the closet enclosure. 

504.6 Domestic clothes dryer ducts. Exhaust ducts for do- 
mestic clothes dryers shall be constructed of metal and shall 
have a smooth interior finish. The exhaust duct shall be a mini- 
mum nominal size of 4 inches ( 1 02 mm) in diameter. The entire 
exhaust system shall be supported and secured in place. The 
male end of the duct at overlapped duct joints shall extend in the 
direction of airflow. Clothes dryer transition ducts used to con- 
nect the appliance to the exhaust duct system shall be limited to 
single lengths not to exceed 8 feet (2438 mm) and shall be Hsted 
and labeled for the application. Transition ducts shall not be 
concealed within construction. 

504.6.1 Maximum length. The maximum length of a 
clothes dryer exhaust duct shall not exceed 25 ft (7620 mm) 
from the dryer location to the outlet terminal. The maximum 
length of duct shall be reduced 272 f^^t for each 45 -degree 
(0.79 rad) bend and 5 feet (1524 mm) for each 90-degree 

1(1.6 rad) bend. The maximum length of the exhaust duct 
does not include the transition duct. 



Exception: Where the make and model of the clothes 
dryer to be installed is known and the manufacturer's in- 
stallation instructions for such dryer are provided to the 
code official, the maximum length of the exhaust duct, in- 
cluding any transition duct, shall be permitted to be in ac- 
cordance with the dryer manufacturer's installation 
instructions. 

504.6.2 Rough-in required. Where a compartment or 
space for a domestic clothes dryer is provided, an exhaust 
duct system shall be installed in accordance with Sections 
504.6 and 504.6.1. 

504.7 Commercial clothes dryers. The installation of dryer 
exhaust ducts serving Type 2 clothes dryers shall comply with 
the appliance manufacturer's installation instructions. Exhaust 
fan motors installed in exhaust systems shall be located outside 
of the airstream. In multiple installafions, the fan shall operate 
continuously or be interlocked to operate when any individual 
unit is operating. Ducts shall have a minimum clearance of 6 
inches (152 mm) to combustible materials. Clothes dryer tran- 
sition ducts used to connect the appliance to the exhaust duct 
system shall be limited to single lengths not to exceed 8 feet 
(2438 mm) in length and shall be listed and labeled for the ap- 
plication. Transition ducts shall not be concealed within con- 
struction. 



SECTION 505 
DOMESTIC KITCHEN EXHAUST EQUIPMENT 

505.1 Domestic systems. Where domestic range hoods and do- 
mestic appliances equipped with downdraft exhaust are located 
within dwelling units, such hoods and appliances shall dis- 
charge to the outdoors through ducts constructed of galvanized 
steel, stainless steel, aluminum or copper. Such ducts shall have 
smooth inner walls and shall be air tight and equipped with a 
backdraft damper. 

Exceptions: 

1 . Where installed in accordance with the manufacturer's 
installation instructions and where mechanical or natu- 
ral ventilation is otherwise provided in accordance 
with Chapter 4, listed and labeled ductiess range hoods 
shall not be required to discharge to the outdoors. 

2. Ducts for domestic kitchen cooking appliances 
equipped with downdraft exhaust systems shall be 
permitted to be constructed of Schedule 40 PVC pipe 
provided that the installation complies with all of the 
following: 

2.1. The duct shall be installed under a concrete 
slab poured on grade. 

2.2. The underfloor trench in which the duct is in- 
stalled shall be completely backfilled with 
sand or gravel. 

2.3. The PVC duct shall extend not greater than 1 
inch (25 mm) above the indoor concrete 
floor surface. 

2.4. The PVC duct shall extend not greater than 1 
inch (25 mm) above grade outside of the 
building. 

2.5. The PVC ducts shall be solvent cemented. 



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SECTION 506 
COMMERCIAL KITCHEN HOOD VENTILATION 
SYSTEM DUCTS AND EXHAUST EQUIPMENT 

506.1 General. Commercial kitchen hood ventilation ducts and 
exhaust equipment shall comply with the requirements of this 
section. Conmiercial kitchen grease ducts shall be designed for 
the type of cooking appliance and hood served. 

506.2 Corrosion protection. Ducts exposed to the outside at- 
mosphere or subject to a corrosive environment shall be pro- 
tected against corrosion in an approved manner. 

506.3 Ducts serving Type I hoods. Type I exhaust ducts shall be 
independent of all other exhaust systems except as provided in 
Section 506.3.5. Commercial kitchen duct systems serving Type 
I hoods shall be designed, constructed and installed in accor- 
dance with Sections 506.3.1 through 506.3.12.3. 

506.3.1 Duct materials. Ducts serving Type I hoods shall 
be constructed of materials in accordance with Sections 
506.3.1.1 and 506.3.1.2. 

506.3.1.1 Grease duct materials. Grease ducts serving 
Type I hoods shall be constructed of steel not less than 
0.055 inch (1.4 mm) (No. 16 Gage) in thickness or stain- 
less steel not less than 0.044 inch (1.1 nmi) (No. 1 8 Gage) 
in thickness. 

Exception: Listed and labeled factory-built commer- 
cial kitchen grease ducts shall be installed in accor- 
dance with Section 304.1. 

506.3.1.2 Makeup air ducts. Make up air ducts connect- 
ing to or within 1 8 inches (457 mm) of a Type I hood shall 
be constructed and installed in accordance with Sections 
603.1, 603.3, 603.4, 603.9, 603.10 and 603.12. Duct in- 
sulation installed within 18 inches (457 mm) of a Type I 
hood shall be noncombustible or shall be listed for the ap- 
plication. 

506.3.2 Joints, seams and penetrations of grease ducts. 

Joints, seams and penetrations of grease ducts shall be made 
with a continuous Hquid-tight weld or braze made on the ex- 
ternal surface of the duct system. 

Exceptions: 

1. Penetrations shall not be required to be welded or 
brazed where sealed by devices that are listed for 
the application. 

2. Internal welding or brazing shall not be prohibited 
provided that the joint is formed or ground smooth 
and is provided with ready access for inspection. 

3. Listed and labeled factory-built commercial 
kitchen grease ducts installed in accordance with 
Section 304.1. 

506.3.2.1 Duct joint types. Duct joints shall be butt 
joints or overlapping duct joints of either the telescoping 
or bell type. Overlapping joints shall be installed to pre- 
vent ledges and obstructions from collecting grease or in- 
terfering with gravity drainage to the intended collection 
point. The difference between the inside cross-sectional 
dimensions of overlapping sections of duct shall not ex- 
ceed 0.25 inch (6 mm). The length of overlap for overlap- 
ping duct joints shall not exceed 2 inches (51 mm). 



506.3.2.2 Duct-to-hood joints. Duct-to-hood joints shall 
be made with continuous internal or external Hquid-tight 
welded or brazed joints. Such joints shall be smooth, ac- 
cessible for inspection, and without grease traps. 

Exceptions: This section shall not apply to: 

1 . A vertical duct-to-hood collar connection made 
in the top plane of the hood in accordance with 
all of the following: 

1.1. The hood duct opening shall have a 
1 -inch-deep (25 mm), full perimeter, 
welded flange turned down into the 
hood interior at an angle of 90 degrees 
from the plane of the opening. 

1.2. The duct shall have a 1 -inch-deep (25 
mm) flange made by a 1-inch by 1-inch 
(25 mm by 25 mm) angle iron welded to 
the fiill perimeter of the duct not less 
than 1 inch (25 mm) above the bottom 
end of the duct. 

1.3. A gasket rated for use at not less than 
1,500°F (815°C) is installed between 
the duct flange and the top of the hood. 

1.4. The duct-to-hood joint shall be secured 
by stud bolts not less than 0.25 inch (6.4 
mm) in diameter welded to the hood 
with a spacing not greater than 4 inches 
(102 mm) on center for the full 
perimeter of the opening. All bolts and 
nuts are to be secured with lock washers. 

2. Listed and labeled duct-to-hood collar connec- 
tions installed in accordance with Section 304. 1 . 

506.3.2.3 Duct-to-exhaust fan connections. Duct- 
to-exhaust fan connections shall be flanged and gasketed 
at the base of the fan for vertical discharge fans; shall be 
flanged, gasketed and bolted to the inlet of the fan for 
side-inlet utility fans; and shall be flanged, gasketed and 
bolted to the inlet and outlet of the fan for in-line fans. 

506.3.2.4 Vibration isolation. A vibration isolation con- 
nector for connecting a duct to a fan shall consist of 
noncombustible packing in a metal sleeve joint of ap- 
proved design or shall be a coated- fabric flexible duct con- 
nector listed and labeled for the application. Vibration 
isolation connectors shall be installed only at the connec- 
tion of a duct to a fan inlet or outlet. 

506.3.3 Grease duct supports. Grease duct bracing and 
supports shall be of noncombustible material securely at- 
tached to the structure and designed to carry gravity and 
seismic loads within the stress limitations of the Interna- 
tional Building Code. Bolts, screws, rivets and other me- 
chanical fasteners shall not penetrate duct walls. 

506.3.4 Air velocity. Grease duct systems serving a Type I 
hood shall be designed and installed to provide an air veloc- 
ity within the duct system of not less than 1,500 feet per 
minute (7.6 m/s). 

Exception: The velocity limitations shall not apply within 
duct transitions utilized to connect ducts to differently 



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EXHAUST SYSTEMS 



sized or shaped openings in hoods and fans, provided that 
such transitions do not exceed 3 feet (914 mm) in length 
and are designed to prevent the trapping of grease. 

506.3.5 Separation of grease duct system. A separate 
grease duct system shall be provided for each Type I hood. A 
separate grease duct system is not required where all of the 
following conditions are met: 

1. All interconnected hoods are located within the same 
story. 

2. All interconnected hoods are located within the same 
room or in adjoining rooms. 

3. Interconnecting ducts do not penetrate assemblies re- 
quired to be fire-resistance rated. 

4. The grease duct system does not serve solid fuel-fired 
appliances. 

506.3.6 Grease duct clearances. Grease duct systems and 
I exhaust equipment serving a Type I hood shall have a clear- 
ance to combustible construction of not less than 18 inches 

1(457 mm), and shall have a clearance to noncombustible con- 
struction and gypsum wallboard attached to noncombustible 
structures of not less than 3 inches (76 nmi). 

Exception: Listed and labeled factory-built conrmiercial 
kitchen grease ducts and exhaust equipment installed in 
accordance with Section 304.1! 

506.3.7 Prevention of grease accumulation in grease 
ducts. Duct systems serving a Type I hood shall be con- 
structed and installed so that grease cannot collect in any por- 
tion thereof, and the system shall slope not less than 
one-fourth unit vertical in 12 units horizontal (2-percent 
slope) toward the hood or toward an approved grease reser- 
voir. Where horizontal ducts exceed 75 feet (22 860 mm) in 
length, the slope shall not be less than one unit vertical in 12 

I units horizontal (8.3-percent slope). 

506.3.8 Grease duct cleanouts and other openings. Grease 
duct systems shall not have openings therein other than those 
required for proper operation and maintenance of the system. 
Any portion of such system having sections not provided with 
access from the duct entry or discharge shall be provided with 
cleanout openings. Cleanout openings shall be equipped with 
tight-fitting doors constructed of steel having a thickness not 
less than that required for the duct. Doors shall be equipped 
with a substantial method of latching, sufficient to hold the 
door tightly closed. Doors shall be designed so that they are op- 
erable without the use of a tool. Door assemblies, including 
any frames and gasketing, shall be approved for the purpose, 
and shall not have fasteners that penetrate the duct. Listed and 
labeled access door assembUes shall be installed in accordance 
with the terms of the listing. 

506.3.8.1 Personnel entry. Where ductwork is large 
enough to allow entry of personnel, not less than one ap- 
proved or listed opening having dimensions not less than 20 
inches by 20 inches (508 mm by 508 mm) shall be provided 
in the horizontal sections, and in the top of vertical risers. 
Where such entry is provided, the duct and its supports shall 
be capable of supporting the additional load and the 
cleanouts specified in Section 506.3.8 are not required. 



506.3.9 Grease duct horizontal cleanouts. Cleanouts lo- 
cated on horizontal sections of ducts shall be spaced not more 
than 20 feet (6096 mm) apart. The cleanouts shall be located 
on the side of the duct with the opening not less than 1.5 
inches (38 mm) above the bottom of the duct, and not less 
than 1 inch (25 mm) below the top of the duct. The opening 
minimum dimensions shall be 12 inches (305 nmi) on each 
side. Where the dimensions of the side of the duct prohibit the 
cleanout installation prescribed herein, the openings shall be 
on the top of the duct or the bottom of the duct. Where located 
on the top of the duct, the opening edges shall be a minimum 
of 1 inch (25 mm) from the edges of the duct. Where located 
in the bottom of the duct, cleanout openings shall be designed 
to provide internal damming around the opening, shall be 
provided with gasketing to preclude grease leakage, shaU pro- 
vide for drainage of grease down the duct around the dam, 
and shall be approved for the application. Where the dimen- 
sions of the sides, top or bottom of the duct preclude the in- 
stallation of the prescribed minimum-size cleanout opening, 
the cleanout shall be located on the duct face that affords the 
largest opening dimension and shall be installed with the 
opening edges at the prescribed distances from the duct edges 
as previously set forth in this section. 

506.3.10 Grease duct enclosure. A grease duct serving a Type 
I hood that penetrates a ceiling, wall or floor shall be enclosed 
from the point of penetration to the outlet terminal. A duct shall 
penetrate exterior walls only at locations where unprotected 
openings are permitted by the International Building Code. 
Ducts shall be enclosed in accordance with the International 
Building Code requirements for shaft construction. The duct 
enclosure shall be sealed around the duct at the point of pene- 
tration and vented to the outside of the building through the use 
of weather-protected openings. Clearance from the duct to the 
interior surface of enclosures of combustible construction shall 
be not less than 1 8 inches (457 mm). Clearance from the duct to 
the interior surface of enclosures of noncombustible construc- 
tion or gypsum wallboard attached to noncombustible struc- 
tures shall be not less than 6 inches (152 mm). The duct 
enclosure shall serve a single grease exhaust duct system and 
shall not contain any other ducts, piping, wiring or systems. 

Exceptions: 

1 . The shaft enclosure provisions of this section shall 
not be required where a duct penetration is protected 
with a through-penetration firestop system classi- 
fied in accordance with ASTM E 8 14 and having an 
"F' and 'T" rating equal to the fire-resistance rating 
of the assembly being penetrated and where the sur- 
face of the duct is continuously covered on all sides 
from the point at which the duct penetrates a ceiling, 
wall or floor to the outlet terminal with a classified 
and labeled material, system, method of construc- 
tion or product specifically evaluated for such pur- 
pose, in accordance with a nationally recognized 
standard for such enclosure materials. Exposed duct 
wrap systems shall be protected where subject to I 
physical damage. ■ 

2. A duct enclosure shall not be required for a grease 
duct that penetrates only a nonfire-resistance-rated 
roof/ceiling assembly. 



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506.3.11 Grease duct fire-resistive access opening. Where 
cleanout openings are located in ducts within a fire-resis- 
tance-rated enclosure, access openings shall be provided in the 
enclosure at each cleanout point. Access openings shall be 
equipped with tight-fitting sliding or hinged doors that are 
equal in fire-resistive protection to that of the shafl: or enclo- 
sure. An approved sign shall be placed on access opening pan- 
els with wording as foUows: "ACCESS PANEL. DO NOT 
OBSTRUCT." 

506.3.12 Exhaust outlets serving TVpe I hoods. Exhaust 
outlets for grease ducts serving Type I hoods shall conform 
to the requirements of Sections 506.3.12.1 through 
506.3.12.3. 

506.3.12.1 Termination above the roof. Exhaust outlets 
that terminate above the roof shall have the discharge 
opening located not less than 40 inches (1016 nmi) above 
the roof surface. 

506.3.12.2 Termination through an exterior wall. Ex- 
haust outlets shall be permitted to terminate through ex- 
terior walls where the smoke, grease, gases, vapors, and 
odors in the discharge from such terminations do not cre- 
ate a public nuisance or a fire hazard. Such terminations 
shall not be located where protected openings are re- 
quired by the International Building Code. Other exterior 
openings shall not be located within 3 feet (914 nmi) of 
such terminations. 

506.3.12.3 Termination location. Exhaust outlets shall 
be located not less than 10 feet (3048 mm) horizontally 
from parts of the same or contiguous buildings, adjacent 
property lines and air intake openings into any building 
and shall be located not less than 10 feet (3048 mm) 
above the adjoining grade level. 

Exception: Exhaust outlets shall terminate not less 
than 5 feet (1524 mm) from an adjacent building, ad- 
jacent property fine and air intake openings into a 
building where air from the exhaust outiet discharges 
^ away from such locations. 

1506.4 Ducts serving T^pe II hoods. Single or combined Type 
II exhaust systems for food-processing operations shall be in- 
dependent of all other exhaust systems. Commercial kitchen 
exhaust systems serving Type II hoods shall comply with Sec- 
tions 506.4.1 and 506.4.2. 

506.4.1 Type II exhaust outlets. Exhaust outlets for ducts 
serving Type II hoods shall comply with Sections 401 .5 and 
401.5.2. Such outlets shall be protected against local 
weather conditions and shall meet the provisions for exte- 
rior wall opening protectives in accordance with the Interna- 
tional Building Code. 

506.4.2 Ducts. Ducts and plenums serving Type II hoods 
shall be constructed of rigid metallic materials. Duct con- 
struction, installation, bracing and supports shall comply 
with Chapter 6. Ducts subject to positive pressure and ducts 
conveying moisture-laden or waste-heat-laden air shall be 
constructed, joined and sealed in an approved manner. 

1506.5 Exhaust equipment. Exhaust equipment, including fans 
and grease reservoirs, shall comply with Section 506.5.1 



through 506.5.5 and shall be of an approved design or shall be 
listed for the application. 

506.5.1 Exhaust fans. Exhaust fan housings serving a Type 
I hood shall be constructed as required for grease ducts in 
accordance with Section 506.3.1.1. 

Exception: Fans listed and labeled in accordance with 
UL 762. 

506.5.1.1 Fan motor. Exhaust fan motors shall be lo- 
cated outside of the exhaust airstream. 

506.5.2 Exhaust fan discharge. Exhaust fans shall be posi- 
tioned so that the discharge will not impinge on the roof, 
other equipment or appUances or parts of the structure. A 
vertical discharge fan shall be manufactured with an ap- 
proved drain outiet at the lowest point of the housing to per- 
mit drainage of grease to an approved grease reservoir. 

506.5.3 Exhaust fan mounting. An upblast fan shall be 
hinged and supplied with a flexible weatherproof electrical 
cable to permit inspection and cleaning. The ductwork shall 
extend a minimum of 18 inches (457 mm) above the roof 
surface. 

506.5.4 Clearances. Exhaust equipment serving a Type I 
hood shall have a clearance to combustible construction of 
not less than 18 inches (457 mm). 

Exception: Factory-built exhaust equipment installed in 
accordance with Section 304.1 and listed for a lesser 
clearance. 

506.5.5 Termination location. The outiet of exhaust equip- 
ment serving Type I hoods, shall be in accordance with Sec- 
tion 506.3.12.3 

Exception: The minimum horizontal distance between 
vertical discharge fans and parapet-type building struc- 
tures shall be 2 feet (610 mm) provided that such struc- 
tures are not higher than the top of the fan discharge 
opening. 



SECTION 507 
COMMERCIAL KITCHEN HOODS 

507.1 General. Commercial kitchen exhaust hoods shall com- 
ply with the requirements of this section. Hoods shall be Type I 
or Type II and shall be designed to capture and confine cooking 
vapors and residues. 

Exceptions: 

1. Factory-built commercial exhaust hoods which are 
tested in accordance with UL 710, listed, labeled and 
installed in accordance with Section 304.1 shall not 
be required to comply with Sections 507.4, 507.7, 
507.11, 507.12, 507.13, 507.14 and 507.15. 

2. Factory-built commercial cooking recirculating systems 
which are tested in accordance with UL 197, hsted, la- 
beled and installed in accordance with Section 304.1 
shall not be required to comply with Sections 507.4, 
507.5, 507.7, 507.12, 507.13, 507.14 and 507.15. 

3. Net exhaust volumes for hoods shall be permitted to 
be reduced during no-load cooking conditions, where 



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engineered or listed multi-speed or variable-speed 
controls automatically operate the exhaust system to 
maintain capture and removal of cooking effluents as 
required by this section. 

507.2 Where required. A Type I or Type II hood shall be in- 
stalled at or above all commercial cooking appliances in accor- 
dance with Sections 507.2.1 and 507.2.2. Where any cooking 
appliance under a single hood requires a Type I hood, a Type I 
hood shall be installed. Where a Type II hood is required, a 
Type I or Type II hood shall be installed. 

507.2.1 Type I hoods. Type I hoods shall be installed where 
cooking appHances produce grease or smoke, such as occurs 
with griddles, fryers, broilers, ovens, ranges and wok 
ranges. 

507.2.2 Type II hoods. Type II hoods shall be installed 
where cooking or dishwashing appliances produce heat or 
steam and do not produce grease or smoke, such as steam- 
ers, kettles, pasta cookers and dishwashing machines. 

Exceptions: 

1 . Under-counter-type commercial dishwashing ma- 
chines. 

2. A Type II hood is not required for dishwashers and 
potwashers that are provided with heat and water 
vapor exhaust systems that are supplied by the ap- 
pliance manufacturer and are installed in accor- 
dance with the manufacturer's instructions. 

507.2.3 Domestic cooking appliances used for commer- 
cial purposes. Domestic cooking appliances utilized for 
commercial purposes shall be provided with Type I or Type 
II hoods as required for the type of appliances and processes 
in accordance with Sections 507.2, 507.2.1 and 507.2.2. 

507.2.4 Solid fuel. Type I hoods for use over soHd 
fuel-burning cooking appliances shall discharge to an ex- 
haust system that is independent of other exhaust systems. 

507.3 Fuel-burning appliances. Where vented fuel-burning 
appliances are located in the same room or space as the hood, 
provisions shall be made to prevent the hood system from inter- 
fering with normal operation of the appliance vents. 

507.4 T^pe I materials. Type I hoods shall be constructed of 
steel not less than 0.043 inch ( 1 .09 mm) (No. 1 8 MSG) in thick- 
ness, or stainless steel not less than 0.037 inch (0.94 mm) (No. 
20 MSG) in thickness. 

507.5 Type II hood materials. Type II hoods shall be con- 
structed of steel not less than 0.030 inch (0.76 mm) (No. 22 
Gage) in thickness, stainless steel not less than 0.024 inch (0.61 
mm) (No. 24 Gage) in thickness, copper sheets weighing not 
less than 24 ounces per square foot (7.3 kg/m^), or of other ap- 
proved material and gage. 

507.6 Supports. Type I hoods shall be secured in place by non- 
combustible supports. All Type I and Type II hood supports shall 
be adequate for the applied load of the hood, the unsupported 
ductwork, the effluent loading, and the possible weight of per- 
sonnel working in or on the hood. 

507.7 Hood joints, seams and penetrations. Hood joints, 
seams and penetrations shall comply with Sections 507.7. 1 and 
507.7.2. 



507.7.1 Type I hoods. External hood joints, seams and pen- 
etrations for Type I hoods shall be made with a continuous 
external liquid-tight weld or braze to the lowest outermost 
perimeter of the hood. Internal hood joints, seams, penetra- 
tions, filter support frames, and other appendages attached 
inside the hood shall not be required to be welded or brazed 
but shall be otherwise sealed to be grease tight. 

Exceptions: 

1 . Penetrations shall not be required to be welded or 
brazed where sealed by devices that are listed for 
the application. 

2. Internal welding or brazing of seams, joints, and 
penetrations of the hood shall not be prohibited 
provided that the joint is formed smooth or ground 
so as to not trap grease, and is readily cleanable. 

507.7.2 Type II hoods. Joints, seams and penetrations for 
Type II hoods shall be constructed as set forth in Chapter 6, 
shall be sealed on the interior of the hood and shall provide a 
smooth surface that is readily cleanable and water tight. 

507.8 Cleaning and grease gutters. A hood shall be designed 
to provide for thorough cleaning of the entire hood. Grease gut- 
ters shall drain to an approved collection receptacle that is fab- 
ricated, designed and installed to allow access for cleaning. 

507.9 Clearances for l^pe I hood. A Type I hood shall be in- 
stalled with a clearance to combustibles of not less than 18 
inches (457 mm). 

Exception: Clearance shall not be required from gypsum 
wallboard attached to noncombustible structures provided 
that a smooth, cleanable, nonabsorbent and noncombustible 
material is installed between the hood and the gypsum wall- 
board over an area extending not less than 18 inches (457 
mm) in all directions from the hood. 

507.10 Hoods penetrating a ceiling. Type I hoods or portions 
thereof penetrating a ceiling, wall or furred space shall comply 
with all the requirements of Section 506.3.10. 

507.11 Grease filters. Type I hoods shall be equipped with 
listed grease filters designed for the specific purpose. 
Grease-collecting equipment shall be provided with access for 
cleaning. The lowest edge of a grease filter located above the 
cooking surface shall be not less than the height specified in Ta- 
ble 507.11. 

TABLE 507.11 

MINIMUM DISTANCE BETWEEN THE LOWEST EDGE OF A 

GREASE FILTER AND THE COOKING SURFACE OR THE 

HEATING SURFACE 



TYPE OF COOKING 
APPLIANCES 


HEIGHT ABOVE COOKING 
SURFACE (feet) 


Without exposed flame 


0.5 


Exposed flame and burners 


2 


Exposed charcoal and charbroil type 


3.5 



For SI: 1 foot = 304.8 mm. 



507.11.1 Criteria. Filters shall be of such size, type and ar- 
rangement as will permit the required quantity of air to pass 
through such units at rates not exceeding those for which the 
filter or unit was designed or approved. Filter units shall be 



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installed in frames or holders so as to be readily removable 
without the use of separate tools, unless designed and in- 
stalled to be cleaned in place and the system is equipped for 
such cleaning in place. Removable filter units shall be of a 
size that will allow them to be cleaned in a dishwashing ma- 
chine or pot sink. Filter units shall be arranged in place or 
provided with drip-intercepting devices to prevent grease or 
other condensate from dripping into food or on food prepa- 
ration surfaces. 

507.11.2 Mounting position. Filters shall be installed at an 
angle of not less than 45 degrees (0.79 rad) from the hori- 
zontal and shall be equipped with a drip tray beneath the 
lower edge of the filters. 

507.12 Canopy size and location. The inside lower edge of 
canopy-type commercial cooking hoods shall overhang or ex- 
tend a horizontal distance of not less than 6 inches (152 mm) 
beyond the edge of the cooking surface, on all open sides. The 
vertical distance between the front lower lip of the hood and the 
cooking surface shall not exceed 4 feet (1219 nun). 

Exception: The hood shall be permitted to be flush with the 
outer edge of the cooking surface where the hood is closed to 
the appliance side by a noncombustible wall or panel. 

507.13 Capacity of hoods. Commercial food service hoods 
shall exhaust a minimum net quantity of air determined in ac- 
cordance with this section and Sections 507.13.1 through 
507.13.4. The net quantity of exhaust air shall be calculated by 
subtracting any airflow supplied directly to a hood cavity from 
the total exhaust flow rate of a hood. Where any combination of 
extra-heavy-duty, heavy-duty, medium-duty, and light-duty 
cooking appliances are utilized under a single hood, the highest 
exhaust rate required by this section shall be used for the entire 
hood. 

507.13.1 Extra-heavy-duty cooking appliances. The mini- 
mum net airflow for Type I hoods used for extra-heavy-duty 
cooking appliances shall be determined as follows: 



lypeofHood 


CFM per linear foot of hood 


Wall-mounted canopy 


550 


Single island canopy 


700 


Double island canopy (per side) 


550 


Backshelf/pass-over 


Not allowed 


Eyebrow 


Not allowed 



For SI: 1 cfm per linear foot = 1 .55 L/s per linear meter. 

507.13.2 Heavy-duty cooking appliances. The minimum 
net airflow for Type I hoods used for heavy-duty cooking 
appliances shall be determined as follows: 



Type of Hood 


CFM per linear foot of hood 


Wall-mounted canopy 


400 


Single island canopy 


600 


Double island canopy (per side) 


400 


Backshelf/pass-over 


400 


Eyebrow 


Not allowed 



507.13.3 Medium-duty cooking appliances. The mini- 
mum net airflow for Type I hoods used for medium-duty 
cooking appliances shall be determined as follows: 



lypeofHood 


CFM 


per 


linear foot of hood 


Wall-mounted canopy 






300 


Single island canopy 






500 


Double island canopy (per side) 






300 


Backshelf/pass-over 






300 


Eyebrow 






250 



For SI: 1 cfm per linear foot = 1.55 L/s per linear meter. 

507.13.4 Light-duty cooking appliances. The minimum 
net airflow for Type I hoods used for light duty cooking ap- 
pliances and food service preparation and cooking opera- 
tions approved for use under a Type II hood shall be 
determined as follows: 



Type of Hood 


CFM per linear foot of hood 


Wall-mounted canopy 


200 


Single island canopy 


400 


Double island canopy (per side) 


250 


Backshelf/pass-over 


250 


Eyebrow 


250 



For SI: 1 cfm per linear foot = 1.55 L/s per linear meter. 



For SI: 1 cfm per linear foot = 1.55 L/s per linear meter. 

507.14 Noncanopy size and location. Noncanopy-type hoods 
shall be located a maximum of 3 feet (914 mm) above the cook- 
ing surface. The edge of the hood shall be set back a maximum 
of 1 foot (305 mm) from the edge of the cooking surface. 

507.15 Exiiaust outlets. Exhaust outlets located within the 
hood shall be located so as to optimize the capture of particu- 
late matter. Each outlet shall serve not more than a 12-foot 
(3658 nun) section of hood. 

507.16 Performance test. A performance test shall be con- 
ducted upon completion and before final approval of the instal- 
lation of a ventilation system serving commercial cooking 
appliances. The test shall verify the rate of exhaust airflow re- 
quired by Section 507.13, makeup airflow required by Section 
508, and proper operation as specified in this chapter. The per- 
mit holder shall furnish the necessary test equipment and de- 
vices required to perform the tests. 

507.16.1 Capture and containment test. The permit 
holder shall verify capture and containment performance of 
the exhaust system. This field test shall be conducted with 
all appliances under the hood at operating temperatures. 
Capture and containment shall be verified visually by ob- 
serving smoke or steam produced by actual or simulated 
cooking, such as with smoke candles, smoke puffers, etc. 



SECTION 508 
COMMERCIAL KITCHEN MAKEUP AIR 

508.1 Makeup air. Makeup air shall be supplied during the op- 
eration of commercial kitchen exhaust systems that are pro- 
vided for commercial cooking appliances. The amount of I 



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makeup air supplied shall be approximately equal to the 
amount of exhaust air. The makeup air shall not reduce the ef- 
fectiveness of the exhaust system. Makeup air shall be provided 
by gravity or mechanical means or both. For mechanical 
makeup air systems, the exhaust and makeup air systems shall 
be electrically interlocked to insure that makeup air is provided 
whenever the exhaust system is in operation. Makeup air intake 
opening locations shall comply with Sections 401.5 and 
401.5.1. 

508.1.1 Makeup air temperature. The temperature differ- 
ential between makeup air and the air in the conditioned 
space shall not exceed 10°F (6°C). 

Exceptions: 

1 . Makeup air that is part of the air-conditioning sys- 
tem. 

2. Makeup air that does not decrease the comfort con- 
ditions of the occupied space. 

508.2 Compensating hoods. Manufacturers of compensating 
hoods shall provide a label indicating minimum exhaust flow 
and/or maximum makeup airflow that provides capture and 
containment of the exhaust effluent. 



SECTION 509 
FIRE SUPPRESSION SYSTEMS 

509.1 Where required. Commercial cooking appliances re- 
quired by Section 507.2.1 to have a Type I hood shall be pro- 
vided with an approved automatic fire suppression system 
complying with the International Building Code and the Inter- 
national Fire Code, 



SECTION 510 
HAZARDOUS EXHAUST SYSTEMS 

510.1 General. This section shall govern the design and con- 
struction of duct systems for hazardous exhaust and shall deter- 
mine where such systems are required. Hazardous exhaust 
systems are systems designed to capture and control hazardous 
emissions generated from product handling or processes, and 
convey those emissions to the outdoors. Hazardous emissions 
include flammable vapors, gases, fumes, mists or dusts, and 
volatile or airborne materials posing a health hazard, such as 
toxic or corrosive materials. For the purposes of this section, 
the health-hazard rating of materials shall be as specified in 
NFPA 704. 

510.2 Where required. A hazardous exhaust system shall be 
required wherever operations involving the handling or pro- 
cessing of hazardous materials, in the absence of such exhaust 
systems and under normal operating conditions, have the po- 
tential to create one of the following conditions: 

1. A flammable vapor, gas, fume, mist or dust is present in 
concentrations exceeding 25 percent of the lower 
flammability limit of the substance for the expected 
room temperature. 

2. A vapor, gas, fume, mist or dust with a health-hazard rat- 
ing of 4 is present in any concentration. 



3. A vapor, gas, fume, mist or dust with a health-hazard rat- 
ing of 1, 2 or 3 is present in concentrations exceeding 1 
percent of the median lethal concentration of the sub- 
stance for acute inhalation toxicity. 

[F] 510.2.1 Lumber yards and woodworking facilities. 

Equipment or machinery located inside buildings at lumber 
yards and woodworking faciUties which generates or emits 
combustible dust shall be provided with an approved 
dust-collection and exhaust system installed in conformance 
with this section and the International Fire Code. Equipment 
and systems that are used to collect, process or convey com- 
bustible dusts shall be provided with an approved explo- 
sion-control system. 

[F] 510.2.2 Combustible fibers. Equipment or machinery 
within a building which generates or emits combustible fi- 
bers shall be provided with an approved dust-collecting and 
exhaust system. Such systems shall comply with this code 
and the International Fire Code. 

510.3 Design and operation. The design and operation of the 
exhaust system shall be such that flammable contaminants are 
diluted in noncontaminated air to maintain concentrations in 
the exhaust flow below 25 percent of the contaminant's lower 
flammability limit. 

510.4 Independent system. Hazardous exhaust systems shall 
be independent of other types of exhaust systems. Incompatible 
materials, as defined in the International Fire Code, shall not be 
exhausted through the same hazardous exhaust system. Haz- 
ardous exhaust systems shall not share common shafts with 
other duct systems, except where such systems are hazardous 
exhaust systems originating in the same fire area. 

Contaminated air shall not be recirculated to occupied areas 
unless the contaminants have been removed. Air contaminated 
with explosive or flammable vapors, fumes or dusts; flamma- 
ble or toxic gases; or radioactive material shall not be 
recirculated. 

510.5 Design. Systems for removal of vapors, gases and smoke 
shall be designed by the constant velocity or equal friction meth- 
ods. Systems conveying particulate matter shall be designed em- 
ploying the constant velocity method. 

510.5.1 Balancing. Systems conveying explosive or radio- 
active materials shall be prebalanced by duct sizing. Other 
systems shall be balanced by duct sizing with balancing de- 
vices, such as dampers. Dampers provided to balance 
air- flow shall be provided with securely fixed minimum-po- 
sition blocking devices to prevent restricting flow below the 
required volume or velocity. 

510.5.2 Emission control. The design of the system shall be 
such that the emissions are confined to the area in which 
they are generated by air currents, hoods or enclosures and 
shall be exhausted by a duct system to a safe location or 
treated by removing contaminants. 

510.5.3 Hoods required. Hoods or enclosures shall be used 
where contaminants originate in a limited area of a space. 
The design of the hood or enclosure shall be such that air 
currents created by the exhaust systems will capture the con- 
taminants and transport them directly to the exhaust duct. 



44 



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510.5.4 Contaminant capture and dilution. The velocity 
and circulation of air in work areas shall be such that con- 
taminants are captured by an airstream at the area where the 
emissions are generated and conveyed into a product-con- 
veying duct system. Contaminated air from work areas 
where hazardous- contaminants are generated shall be di- 
luted below the thresholds specified in Section 510.2 with 
air that does not contain other hazardous contaminants. 

510.5.5 Makeup air. Makeup air shall be provided at a rate 
approximately equal to the rate that air is exhausted by the 
hazardous exhaust system. Makeup-air intakes shall be lo- 
cated so as to avoid recirculation of contaminated air. 

510.5.6 Clearances. The minimum clearance between 
hoods and combustible construction shall be the clearance 
required by the duct system. 

510.5.7 Ducts. Hazardous exhaust duct systems shall ex- 
tend directly to the exterior of the building and shall not ex- 
tend into or through ducts and plenums. 

510.6 Penetrations. Penetrations of structural elements by a 
hazardous exhaust system shall conform to Sections 510.6.1 
through 510.6.3. 

Exception: Duct penetrations within H-5 occupancies as al- 
lowed by the International Building Code. 

510.6.1 Floors. Hazardous exhaust systems that penetrate a 
floor/ceiling assembly shall be enclosed in a fire-resis- 
tance-rated shaft constructed in accordance with the Inter- 
national Building Code. 

510.6.2 Wall assemblies. Hazardous exhaust duct systems 
that penetrate fire-resistance-rated wall assembUes shall be 
enclosed in fire-resistance-rated construction from the point 
of penetration to the outlet terminal, except where the inte- 
rior of the duct is equipped with an approved automatic fire 
suppression system. Ducts shall be enclosed in accordance 
with the International Building Code requirements for shaft 
construction and such enclosure shall have a minimum 
fire-resistance-rating of not less than the highest fire-resis- 
tance-rated wall assembly penetrated. 

510.6.3 Fire walls. Ducts shall not penetrate a fire wall. 

510.7 Suppression required. Ducts shall be protected with an 
approved automatic fire suppression system installed in accor- 
dance with the International Building Code. 

Exceptions: 

1. An approved automatic fire suppression system shall 
not be required in ducts conveying materials, fumes, 
mists and vapors that are nonflammable and 
noncombustible under all conditions and at any con- 
centrations. 

2. An approved automatic fire suppression system shall 
not be required in ducts where the largest cross-sec- 
tional diameter of the duct is less than 10 inches (254 
mm). 

510.8 Duct construction. Ducts utilized to convey hazardous 
exhaust shall be constructed of approved G90 galvanized sheet 
steel, with a minimum nominal thickness as specified in Table 
510.8. 



Nonmetallic ducts utilized in systems exhausting nonflam- 
mable corrosive fumes or vapors shall be listed and labeled. 
Nonmetalhc duct shall have a flame spread index of 25 or less 
and a smoke-developed index of 50 or less, when tested in ac- 
cordance with ASTM E 84. Ducts shall be approved for instal- 
lation in such an exhaust system. 

Where the products being exhausted are detrimental to the 
duct material, the ducts shall be constructed of alternative ma- 
terials that are compatible with the exhaust. 

TABLE 510.8 
MINIMUM DUCT THICKNESS 



DIAMETER OF DUCT 

OR MAXIMUM SIDE 

DIMENSION 


MINIMUM NOMINAL THICKNESS 


Nonabrasive 
materials 


Nonabrasive/ 
Abrasive 
materials 


Abrasive 
materials 


0-8 inches 


0.028 inch 
(No. 24 Gage) 


0.034 inch 
(No. 22 Gage) 


0.040 inch 
(No. 20 Gage) 


9-18 inches 


0.034 inch 
(No. 22 Gage) 


0.040 inch 
(No. 20 Gage) 


0.052 inch 
(No. 18 Gage) 


19-30 inches 


0.040 inch 
(No. 20 Gage) 


0.052 inch 
(No. 18 Gage) 


0.064 inch 
(No. 16 Gage) 


Over 30 inches 


0.052 inch 
(No. 18 Gage) 


0.064 inch 
(No. 16 Gage) 


0.079 inch 
(No. 14 Gage) 



For SI: 1 inch = 25.4 mm. 

510.8.1 Duct joints. Ducts shall be made tight with lap joints 
having a minimum lap of 1 inch (25 mm). 

510.8.2 Clearance to combustibles. Ducts shall have a 
clearance to combustibles in accordance with Table 5 10.8.2. 
Exhaust gases having temperatures in excess of 600 °F 
(316° C) shall be exhausted to a chimney in accordance with 
Section 511.2. 

TABLE 510.8.2 
CLEARANCE TO COMBUSTIBLES 



TYPE OF EXHAUST OR 
TEMPERATURE OF EXHAUST (T) 


CLEARANCE TO COMBUSTIBLES 
(inches) 


Less than 100 


1 


100-600 


12 


Flammable vapors 


6 



For SI: 1 inch = 25.4 mm, °C = [(^F)- 32]/l .8. 

510.8.3 Explosion relief. Systems exhausting potentially ex- 
plosive mixtures shall be protected with an approved explo- 
sion relief system or by an approved explosion prevention 
system designed and installed in accordance with NFPA 69. 
An explosion relief system shall be designed to minimize the 
structural and mechanical damage resulting from an explo- 
sion or deflagration within the exhaust system. An explosion 
prevention system shall be designed to prevent an explosion 
or deflagration from occurring. 

510.9 Supports. Ducts shall be supported at intervals not ex- 
ceeding 10 feet (3048 mm). Supports shall be constructed of 
noncombustible material. ; 



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SECTION 511 

DUST, STOCK AND REFUSE 

CONVEYING SYSTEMS 

511.1 Dust, stock and refuse conveying systems. Dust, stock 
and refuse conveying systems shall comply with the provisions 
of Section 5 10 and Sections 511.1.1 through 511.2. 

511.1.1 Collectors and separators. Cyclone collectors and 
separators and associated supports shall be constructed of 
noncombustible materials and shall be located on the exterior 
of the building or structure. A collector or separator shall not 
be located nearer than 10 feet (3048 mm) to combustible con- 
struction or to an unprotected wall or floor opening, unless 
the collector is provided with a metal vent pipe that extends 
above the highest part of any roof within a distance of 30 feet 
(9144 mm). 

511.1.2 Discharge pipe. Discharge piping shall conform to 
the requirements for ducts, including clearances required 
for high-heat appliances, as contained in this code. A deliv- 
ery pipe from a cyclone collector shall not convey refuse di- 
rectly into the firebox of a boiler, furnace, dutch oven, refuse 
burner, incinerator or other appliance. 

511.1.3 Conveying system exhaust discharge. An exhaust 
system shall discharge to the outside of the building either 
directly by flue, or indirectly through the separator, bin or 
vault into which the system discharges. 

511.1.4 Spark protection. The outlet of an open-air ex- 
haust terminal shall be protected with an approved metal or 
other noncombustible screen to prevent the entry of sparks. 

511.1.5 Explosion relief vents. A safety or explosion re- 
lief vent shall be provided on all systems that convey com- 
bustible refuse or stock of an explosive nature, in 



accordance with the requirements of the International 
Building Code. 

511.1.5.1 Screens. Where a screen is installed in a safety 
relief vent, the screen shall be attached so as to permit 
ready release under the explosion pressure. 

511.1.5.2 Hoods. The relief vent shall be provided with 
an approved noncombustible cowl or hood, or with a 
counterbalanced relief valve or cover arranged to prevent 
the escape of hazardous materials, gases or liquids. 

511.2 Exhaust outlets. Outlets for exhaust that exceed 600°F 
(3 15 °C) shall be designed as a chimney in accordance with Ta- 
ble 511.2. 

The termination point for exhaust ducts discharging to the at- 
mosphere shall not be less than the following: 

1. Ducts conveying explosive or flammable vapors, fumes 
or dusts; 30 feet (9144 mm) from property line; 10 feet 
(3048 mm) from openings into the building; 6 feet (1829 
mm) from exterior walls or roofs; 30 feet (9144 mm) 
from combustible walls or openings into the building 
which are in the direction of the exhaust discharge; and 
10 feet (3048 mm) above adjoining grade. 

2. Other product-conveying outlets: 10 feet (3048 mm) 
from property line; 3 feet (914 mm) from exterior wall or 
roof; 10 feet (3048 mm) from openings into the building; 
and 10 feet (3048 mm) above adjoining grade. 

3. Environmental air duct exhaust: 3 feet (914 mm) from 
property line; and 3 feet (914 mm) from openings into the 
building. 



TABLE 511 .2 

CONSTRUCTION, CLEARANCE AND TERMINATION REQUIREMENTS FOR 

SINGLE-WALL METAL CHIMNEYS 



CHIMNEYS 
SERVING 


MINIMUM THICKNESS 


TERMINATION 


CLEARANCE 


Walls 
(inch) 


Lining 


Above 

roof 

opening 

(feet) 


Above any part of 
building within (feet) 


Combustible 

construction 

(inches) 


Noncombustible 
construction 


10 


25 


50 


Interior 
inst. 


Exterior 
inst. 


Interior 
inst. 


Exterior 
inst. 


Low-heat appliances 
(1,000°F normal 
operation) 


0.127 
(No. 10 MSG) 


None 


3 


2 


— 


— 


18 


6 


Up tol8" diameter, 2" 
Over 18" diameter, 4" 


Medium-heat 
appliances 
(2,000°F maximum)'' 


0.127 
(No. 10 MSG) 


Uptol8"dia.— 2V/ 

Over 18"-4V2" 

On4V2"bed 


10 


— 


10 


— 


36 


24 


High-heat appliances 
(Over 2,000°F)^ 


0.127 
(No. 10 MSG) 


4V2" laid on 4V2" bed 


20 


— 




20 


See Note c 



For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, ^C = [(°F)-32]/1.8. 

a. Lining shall extend from bottom to top of outlet. 

b. Lining shall extend from 24 inches below connector to 24 feet above. 

c. Clearance shall be as specified by the design engineer and shall have sufficient clearance from buildings and structures to avoid overheating combustible materials 
(maximum 160°F). 



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SECTION 512 
SUBSLAB SOIL EXHAUST SYSTEMS 

512.1 General. When a subslab soil exhaust system is provided, 
the duct shall conform to the requirements of this section. 

512.2 Materials. Subslab soil exhaust system duct material 
shall be air duct material listed and labeled to the requirements 
of UL 1 8 1 for Class air ducts, or any of the following piping 
materials that comply with the International Plumbing Code as 
building sanitary drainage and vent pipe: cast iron; galvanized 
steel; brass or copper pipe; copper tube of a weight not less than 
that of copper drainage tube, Type DWV; and plastic piping. 

512.3 Grade. Exhaust system ducts shall not be trapped and 
shall have a minimum slope of one-eighth unit vertical in 12 
units horizontal (1 -percent slope). 

512.4 Termination. Subslab soil exhaust system ducts shall 
extend through the roof and terminate at least 6 inches (152 
mm) above the roof and at least 10 feet (3048 mm) from any op- 
erable openings or air intake. 

512.5 Identification. Subslab soil exhaust ducts shall be per- 
manently identified within each floor level by means of a tag, 
stencil or other approved marking. 



SECTION 513 
SMOKE CONTROL SYSTEMS 

[B] 513.1 Scope and purpose. This section applies to mechani- 
cal and passive smoke control systems that are required by the 
International Building Code. The purpose of this section is to es- 
tablish minimum requirements for the design, installation and 
acceptance testing of smoke control systems that are intended to 
provide a tenable environment for the evacuation or relocation of 
occupants. These provisions are not intended for the preserva- 
tion of contents, the timely restoration of operations, or for assis- 
tance in fire suppression or overhaul activities. Smoke control 
systems regulated by this section serve a different purpose than 
the smoke- and heat- venting provisions found in Section 910 of 
the International Building Code. 

[B] 513.2 General design requirements. Buildings, structures, 
or parts thereof required by this code to have a smoke control sys- 
tem or systems shall have such systems designed in accordance 
with the applicable requirements of Section 909 of the Interna- 
tional Building Code and the generally accepted and well-estab- 
lished principles of engineering relevant to the design. The 
construction documents shall include sufficient information and 
detail to describe adequately the elements of the design necessary 
for the proper implementation of the smoke control systems. 
These documents shall be accompanied with sufficient informa- 
tion and analysis to demonstrate compUance with these provisions 

[B] 513.3 Special inspection and test requirements. In addi- 
tion to the ordinary inspection and test requirements which 
buildings, structures and parts thereof are required to undergo, 
smoke control systems subject to the provisions of Section 909 
of the International Building Code shall undergo special inspec- 
tions and tests sufficient to verify the proper commissioning of 
the smoke control design in its final installed condition. The de- 
sign submission accompanying the construction documents 
shall clearly detail procedures and methods to be used and the 
items subject to such inspections and tests. Such commissioning 



shall be in accordance with generally accepted engineering prac- 
tice and, where possible, based on published standards for the 
particular testing involved. The special inspections and tests re- 
quired by this section shall be conducted under the same terms as 
found in Section 1704 of the International Building Code. 

[B] 513.4 Analysis. A rational analysis supporting the types of 
smoke control systems to be employed, their methods of opera- 
tion, the systems supporting them, and the methods of con- 
struction to be utilized shall accompany the submitted 
construction documents and shall include, but not be limited to, 
the items indicated in Sections 513.4.1 through 513.4.6. 

[B] 513.4.1 Stack effect. The system shall be designed such 
that the maximum probable normal or reverse stack effects will 
not adversely interfere with the system's capabilities. In deter- 
mining the maximum probable stack effects, altitude, eleva- 
tion, weather history and interior temperatures shall be used. 

[B] 513.4.2 Temperature effect of fire. Buoyancy and expan- 
sion caused by the design fire in accordance with Section 5 1 3.9 
shall be analyzed. The system shall be designed such that these 
effects do not adversely interfere with its capabilities. 

[B] 513.4.3 Wind effect. The design shall consider the ad- 
verse effects of wind. Such consideration shall be consistent 
with the wind-loading provisions of the International Build- 
ing Code. 

[B] 513.4.4 HVAC systems. The design shall consider the ef- 
fects of the heating, ventilating and air-conditioning (HVAC) 
systems on both smoke and fire transport. The analysis shall 
include all permutations of systems' status. The design shall 
consider the effects of fire on the HVAC systems. 

[B] 513.4.5 Climate. The design shall consider the effects 
of low temperatures on systems, property and occupants. 
Air inlets and exhausts shall be located so as to prevent snow 
or ice blockage. 

[B] 513.4.6 Duration of operation. All portions of active or 
passive smoke control systems shall be capable of continued 
operation after detection of the fire event for not less than 20 
minutes. 

[B] 513.5 Smoke barrier construction. Smoke barriers shall 
comply with the International Building Code. Smoke barriers 
shall be constructed and sealed to limit leakage areas exclusive 
of protected openings. The maximum allowable leakage area 
shall be the aggregate area calculated using the following leak- 
age area ratios: 

I.Walls: AM, = 0.00100 

2. Exit enclosures: AIA^ = 0.00035 

3. All other shafts: A/A^ = 0.00150 

4. Floors and roofs: A/A^ = 0.00050 
where: 

A = Total leakage area, square feet (m^). 

A/r = Unit floor or roof area of barrier, square feet (m^). 

A, = Unit wall area of barrier, square feet (m^). 

The leakage area ratios shown do not include openings due 
to doors, operable windows or similar gaps. These shall be in- 
cluded in calculating the total leakage area. 



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[B] 513.5.1 Leakage area. Total leakage area of the barrier 
is the product of the smoke barrier gross area times the al- 
lowable leakage area ratio, plus the area of other openings 
such as gaps and operable windows. Compliance shall be 
determined by achieving the minimum air pressure differ- 
ence across the barrier with the system in the smoke control 
mode for mechanical smoke control systems. Passive 
smoke control systems tested using other approved means 
such as door fan testing shall be as approved by the code of- 
ficial. 

[B] 513.5.2 Opening protection. Openings in smoke barri- 
ers shall be protected by automatic-closing devices actuated 
by the required controls for the mechanical smoke control 
system. Door openings shall be protected by door assem- 
blies complying with the requirements of the International 
Building Code for doors in smoke barriers. 

Exceptions: 

1. Passive smoke control systems with auto- 
matic-closing devices actuated by spot-type 
smoke detectors listed for releasing service in- 
stalled in accordance with the International Build- 
ing Code, 

2. Fixed openings between smoke zones which are 
protected utilizing the airflow method. 

3. In Group 1-2 where such doors are installed across 
corridors, a pair of opposite-swinging doors with- 
out a center mullion shall be installed having vi- 
sion panels with approved fire-rated glazing 
materials in approved fire-rated frames, the area of 
which shall not exceed that tested. The doors shall 
be close-fitting within operational tolerances, and 
shall not have undercuts, louvers or grilles. The 
doors shall have head and jamb stops,- astragals or 
rabbets at meeting edges and automatic-closing 
devices. Positive latching devices are not required. 

4. Group 1-3. 

5. Openings between smoke zones with clear ceiling 
heights of 14 feet (4267 mm) or greater and bank 
down capacity of greater than 20 minutes as deter- 
mined by the design fire size. 

[B] 513.5.2.1 Ducts and air transfer openings. Ducts 
and air transfer openings are required to be protected 
with a minimum Class II, 250 °F (121 °C) smoke damper 
complying with the International Building Code. 

[B] 513.6 Pressurization method. The primary mechanical 
means of controlling smoke shall be by pressure differences 
across smoke barriers. Maintenance of a tenable environment 
is not required in the smoke control zone of fire origin. 

[B] 513.6.1 Minimum pressure difference. The minimum 
pressure difference across a smoke barrier shall be 
0.05-inch water gage (12.4 Pa) in fully sprinklered build- 
ings. 

In buildings permitted to be other than fully sprinklered, 
the smoke control system shall be designed to achieve pres- 
sure differences at least two times the maximum calculated 
pressure difference produced by the design fire. 



[B] 513.6.2 Maximum pressure difference. The maximum 
air pressure difference across a smoke barrier shall be deter- 
mined by required door-opening or closing forces. The actual 
force required to open exit doors when the system is in the 
smoke control mode shall be in accordance with the Interna- 
tional Building Code. Opening and closing forces for other 
doors shall be determined by standard engineering methods for 
the resolution of forces and reactions. The calculated force to 
set a side-hinged, swinging door in motion shall be deter- 
mined by: 



F=F^,■^-K{WA^P)l2{W'd) 



(Equation 5-2) 



where: 

A = Door area, square feet (m^). 

d = Distance from door handle to latch edge of door, 





feet (m). 


F 


= Total door opening force, pounds (N). 


F,c 


= Force required to overcome closing device, 
pounds (N). 


K 


= Coefficient 5.2 (1.0). 


W 


= Door width, feet (m). 



AP = Design pressure difference, inches (Pa) water gage. 

[B] 513.7 Airflow design method. When approved by the 
code official, smoke migration through openings fixed in a per- 
manently open position, which are located between smoke con- 
trol zones by the use of the airflow method, shall be permitted. 
The design airflows shall be in accordance with this section. 
Airflow shall be directed to hmit smoke migration from the fire 
zone. The geometry of openings shall be considered to prevent 
flow reversal from turbulent effects. 

[B] 513.7.1 Velocity. The minimum average velocity 
through a fixed opening shall not be less than: 

V = 2 1 7.2 [/i {Tf- T,)/(Tf-\- 460)] '^^ (Equation 5-3) 

For SI: v= 119.9 [h (7}- rj/7}]'^^ 

where: 

H = Height of opening, feet (m). 

7} = Temperature of smoke, °F (K). 

T^ = Temperature of ambient air, °F (K). 

V = Air velocity, feet per minute (m/minute). 

[B] 513.7.2 Proliibited conditions. This method shall not 
be employed where either the quantity of air or the velocity 
of the airflow will adversely affect other portions of the 
smoke control system, unduly intensify the fire, disrupt 
plume dynamics or interfere with exiting. In no case shall 
airflow toward the fire exceed 200 feet per minute (1.02 
m/s). Where the formula in Section 513.7.1 requires airflow 
to exceed this limit, the airflow method shall not be used. 

[B] 513.8 Exhaust method. When approved by the code offi- 
cial, mechanical smoke control for large enclosed volumes, 
such as in atria or malls, shall be permitted to utilize the exhaust 



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method. The design exhaust volumes shall be in accordance 
with this section. 

[B] 513.8.1 Exhaust rate. The height of the lowest horizontal 
surface of the accumulating smoke layer shall be maintained 
at least 10 feet (3048 mm) above any walking surface which 
forms a portion of a required egress system widiin the smoke 
zone. The required exhaust rate for the zone shall be the larg- 
est of the calculated plume mass flow rates for the possible 
plume configurations. Provisions shall be made for natural or 
mechanical supply of outside air from outside or adjacent 
smoke zones to make up for the air exhausted. Makeup air- 
flow rates, when measured at the potential fire location, shall 
not exceed 200 feet per minute ( 1 .02 m/s) toward the fu-e. The 
temperature of the makeup air shall be such that it does not 
expose temperature- sensitive fire protection systems beyond 
their limits. 

[B] 513.8.2 Axisymmetric plumes. The plume mass flow 
rate (m^), in pounds per second (kg/s), shall be determined 
by placing the design fire center on the axis of the space be- 
ing analyzed. The limiting flame height shall be determined 
by: 



z,= 0.533Q, 



(Equation 5-4) 



ForSI:zp0.166a^5 

where: 

nip = Plume mass flow rate, pounds per second (kg/s). 

Q = Total heat output. 

Q^ = Convective heat output, British thermal units per 
second (kW). 

(The value of Q^ shall not be taken as less than 
0.700. 

z = Height from top of fuel surface to bottom of smoke 
layer, feet (m). 

Zi = Limiting flame height, feet (m). The z, value must be 
greater than the fuel equivalent diameter (see Sec- 
tion 513.9). 

for z>Zi 

m^ = 0.022a'^V^^ + 0.00422, 

For SI: m^ = 0.0712,''^ + O.OOlSg, 

for z = Zi 

m,= 0.01ia 
For SI: m^ = 0.0352, 

for z<Zi 

m^=OmOSQ,'"z 
For SI: m^ = 0.0322,^/5^ 

To convert m^ from pounds per second of mass flow to a vol- 
umetric rate, the following formula shall be used: 



V=60mp/p 



(Equation 5-5) 



p = Density of air at the temperature of the smoke layer, 
pounds per cubic feet (T: in °F)[kg/m^ (T: in "*€)]. 

[B] 513.8.3 Balcony spill plumes. The plume mass flow 
rate (m^) for spill plumes shall be determined using the geo- 
metrically probable width based on architectural elements 
and projections in the following formula: 



m =0.124(2W2)'^X^, + 0.25/7) 



(Equation 5-6) 



For SI: m^ = 0.36(2W2)'/3(^^ + o.25//) 

where: 

H = Height above fire to underside of balcony, feet (m) 

nip - Plume mass flow rate, pounds per second (kg/s). 

2 = Total heat output. 

W = Plume width at point of spill, feet (m). 

Zb = Height from balcony, feet (m). 

[B] 513.8.4 Window plumes. The plume mass flow rate 
(nip) shall be determined from: 

mp= 0,011 {A JiJ'^) "\z^ + af'^ + 0. 1 MJiJ"" (Equation 5-7) 

For SI: m^= 0.68(A^,^/2)i/3(^^ + ^yi2 + \,5AJi^ '^^ 

where: 

A^ = Area of the opening, square feet (m^). 

H^ = Height of the opening, feet (m). 

Mp = Plume mass flow rate, pounds per second (kg/s). 

z,^ = Height from the top of the window or opening to the 
bottom of the smoke layer, feet (m). 

[B] 513.8.5 Plume contact with walls. When a plume con- 
tacts one or more of the surrounding walls, the mass flow 
rate shall be adjusted for the reduced entrainment resulting 
from the contact provided that the contact remains constant. 
Use of this provision requires calculation of the plume di- 
ameter, that shall be calculated by: 



d = 0.48 [(T, + 460)/(r^ + 460)] '^h 



(Equation 5-8) 



where: 

V = Volumetric flow rate, cubic feet per minute (mVs). 



For SI: d = 0.48 {TJT^'h 

where: 

d = Plume diameter, feet (m). 

T ^ - Ambient air temperature, °F (K). 

T c - Plume centerline temperature, °F (K). 

= 0.6 (r, + 460) Qr z ■'" + t; 

z = Height at which T^ is determined, feet (m). 

For SI: T, = 0.08 T, Q,^^ z "^'^ + T, 

[B] 513.9 Design fire. The design fire shall be based on a 2 of 
not less than 5,000 Btu per second (5275kW) unless a rational 
analysis is performed by the registered design professional 
and approved by the code official. The design fire shall be 



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based on the analysis in accordance with Section 513.4 and 
this section. 

[B] 513.9.1 Factors considered. The engineering analysis 
shall include the characteristics of the fuel, fuel load, effects 
included by the fire, and whether the fire is likely to be steady 
or unsteady. 

[B] 513.9.2 Separation distance. Detenrdnation of the de- 
sign fire shall include consideration of the type of fuel, fuel 
spacing and configuration. The ratio of the separation dis- 
tance to the fuel equivalent radius shall not be less than 4. 
The fuel equivalent radius shall be the radius of a circle of 
equal area to floor area of the fuel package. The design fire 
shall be increased if other combustibles are within the sepa- 
ration distance as determined by: 



R=[QI{\2 q")]'^ 



(Equation 5-9) 



where: 



q" - Incident radiant heat flux required for nonpiloted ig- 
nition, Btu/ft^ • s (W/m^). 

Q = Heat release from fire, Btu/s (kW). 

R = Separation distance from target to center of fuel 
package, feet (m). 

[B] 513.9.3 Heat-release assumptions. The analysis shall 
make use of the best available data from approved sources 
and shall not be based on excessively stringent limitations 
of combustible material. 

[B] 513.9.4 Sprinkler effectiveness assumptions. A docu- 
mented engineering analysis shall be provided for condi- 
tions that assume fire growth is halted at the time of 
sprinkler activation. 

[B] 513.10 Equipment. Equipment such as, but not Hmited to, 
fans, ducts, automatic dampers and balance dampers shall be 
suitable for their intended use, suitable for the probable expo- 
sure temperatures that the rational analysis indicates, and as ap- 
proved by the code official. 

[B] 513.10.1 Exhaust fans. Components of exhaust fans 
shall be rated and certified by the manufacturer for the prob- 
able temperature rise to which the components will be ex- 
posed. This temperature rise shall be computed by: 



T, = (QJmc) + (TJ 



(Equation 5-10) 



where: 

c = Specific heat of smoke at smoke-layer temperature, 
Btu/lb°F(kJ/kg X K). 

m = Exhaust rate, pounds per second (kg/s). 

l2c = Convecdve heat output of fire, Btu/s (kW). 

T a = Ambient temperature, °¥ (K). 

T , = Smoke temperature, °F (K). 

Exception: Reduced Ts as calculated based on the assur- 
ance of adequate dilution air. 

[B] 513.10.2 Ducts. Duct materials and joints shall be capa- 
ble of withstanding the probable temperatures and pressures 



to which they are exposed as determined in accordance with 
Section 513.10.1. Ducts shall be constructed and supported 
in accordance with Chapter 6. Ducts shall be leak tested to 
1 .5 times the maximum design pressure in accordance with 
nationally accepted practices. Measured leakage shall not 
exceed 5 percent of design flow. Results of such testing shall 
be a part of the documentation procedure. Ducts shall be 
supported directly from fire-resistance-rated structural ele- 
ments of the building by substantial, noncombustible sup- 
ports. 

Exception: Flexible connections, for the purpose of vibra- 
tion isolation, that are constructed of approved fire-resis- 
tance-rated materials. 

[B] 513.10.3 Equipment, inlets and outlets. Equipment 
shall be located so as to not expose uninvolved portions of 
the building to an additional fire hazard. Outdoor air inlets 
shall be located so as to minimize the potential for introduc- 
ing smoke or flame into the building. Exhaust outlets shall 
be so located as to minimize reintroducfion of smoke into 
the building and to limit exposure of the building or adjacent 
buildings to an additional fire hazard. 

[B] 513.10.4 Automatic dampers. Automatic dampers, re- 
gardless of the purpose for which they are installed within 
the smoke control system, shall be listed and conform to the 
requirements of approved recognized standards. 

[B] 513.10.5 Fans. In addition to other requirements, 
belt-driven fans shall have 1.5 times the number of belts re- 
quired for the design duty with the minimum number of belts 
being two. Fans shall be selected for stable performance based 
on normal temperature and, where applicable, elevated tem- 
perature. Calculations and manufacturer's fan curves shall be 
part of the documentation procedures. Fans shall be supported 
and restrained by noncombustible devices in accordance with 
the structural design requirements of the International Build- 
ing Code. Motors driving fans shall not be operating beyond 
their nameplate horsepower (kilowatts) as determined from 
measurement of actual current draw. Motors driving fans shall 
have a minimum service factor of 1.15. 

[B] 513.11 Power systems. The smoke control system shall be 
supplied with two sources of power. Primary power shall be the 
normal building power systems. Secondary power shall be from 
an approved standby source complying with the ICC Electrical 
Code. The standby power source and its transfer switches shall 
be in a separate room from the normal power transformers and 
switch gear and shall be enclosed in a room constructed of not 
less than 1-hour fire-resistance-rated fire barriers, ventilated di- 
rectly to and from the exterior. Power distribution from the two 
sources shall be by independent routes. Transfer to full standby 
power shall be automatic and within 60 seconds of failure of the 
primary power. The systems shall comply with the ICC Electri- 
cal Code, 

[B] 513.11.1 Power sources and power surges. Elements of 
the smoke management system relying on volatile memories 
or the like shall be supphed with uninterruptible power 
sources of sufficient duration to span 15 -minute primary 
power interruption. Elements of the smoke management sys- 
tem susceptible to power surges shall be suitably protected by 
conditioners, suppressors or other approved means. 



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[B] 513.12 Detection and control systems. Fire detection sys- 
tems providing control input or output signals to mechanical 
smoke control systems or elements thereof shall comply with the 
requirements of Chapter 9 of the International Building Code 
and NFPA 72. Such systems shall be equipped with a control unit 
complying with UL 864 and Usted as smoke control equipment. 

Control systems for mechanical smoke control systems shall 
include provisions for verification. Verification shall include 
positive confirmation of actuation, testing, manual override, 
the presence of power downstream of all disconnects and, 
through a preprogrammed weekly test sequence report, abnor- 
mal conditions audibly, visually and by printed report. 

[B] 513.12.1 Wiring. In addition to meeting the require- 
ments of the ICC Electrical Code, all wiring, regardless of 
voltage, shall be fully enclosed within continuous raceways. 

[F] 513.12.2 Activation. Smoke control systems shall be 
activated in accordance with the International Building 
Code. 

[F] 513.12.3 Automatic control. Where completely auto- 
matic control is required or used, the automatic control se- 
quences shall be initiated from an appropriately zoned 
automatic sprinkler system complying with Section 
903.3.1.1 of the International Fire Code or from manual 
controls that are readily accessible to the fire department, 
and any smoke detectors required by engineering analysis. 

[B] 513.13 Control-air tubing. Control-air tubing shall be of 
sufficient size to meet the required response times. Tubing shall 
be flushed clean and dry prior to final connections. Tubing shall 
be adequately supported and protected from damage. Tubing 
passing through concrete or masonry shall be sleeved and pro- 
tected from abrasion and electrolytic action, 

[B] 513.13.1 Materials. Control-air tubing shall be 
hard-drawn copper, Type L, ACR in accordance with ASTM 
B 42, ASTM B 43, ASTM B 68, ASTM B 88, ASTM B 251 
and ASTM B 280. Fittings shall be wrought copper or brass, 
solder type in accordance with ASME B16.18 or ASME 
B 16.22. Changes in direction shall be made with appropriate 
tool bends. Brass compression- type fittings shall be used at 
final connection to devices; other joints shall be brazed using 
a BCuP5 brazing alloy with solidus above 1,100°F (593°C) 
and Uquids below 1,500°F (816°C). Brazing flux shall be 
used on copper- to-brass joints only. 

Exception: Nonmetallic tubing used within control pan- 
els and at the final connection to devices provided all of 
the following conditions are met: 

1. Tubing shall be listed by an approved agency for 
flame and smoke characteristics. 

2. Tubing and connected device shall be completely 
enclosed within a galvanized or paint-grade steel 
enclosure of not less than 0.030 inch (0.76 mm) 
(No. 22 galvanized sheet gage) thickness. Entry to 
the enclosure shall be by copper tubing with a pro- 



tective gromrriet of neoprene or teflon or by 
suitable brass compression to male barbed adapter. 

3. Tubing shall be identified by appropriately docu- 
mented coding. 

4. Tubing shall be neatly tied and supported within 
the enclosure. Tubing bridging cabinets and doors 
or moveable devices shall be of sufficient length to 
avoid tension and excessive stress. Tubing shall be 
protected against abrasion. Tubing serving devices 
on doors shall be fastened along hinges. 

[B] 513.13.2 Isolation from other functions. Control tub- 
ing serving other than smoke control functions shall be iso- 
lated by automatic isolation valves or shall be an 
independent system. 

[B] 513.13.3 Testing. Test control-air tubing at three times 
the operating pressure for not less than 30 minutes without 
any noticeable loss in gauge pressure prior to final connec- 
tion to devices. 

[B] 513.14 Marking and identification. The detection and 
control systems shall be clearly marked at all junctions, ac- 
cesses and terminations. 

[F] 513.15 Control diagrams. Identical control diagrams shall 
be provided and maintained as required by the International 
Fire Code. 

[F] 513.16 Fire fighter's smoke control panel. Afire fighter's 
smoke control panel for fire department emergency response 
purposes only shall be provided in accordance with the Inter- 
national Fire Code. 

[F] 513.17 System response time. Smoke control system acti- 
vation shall comply with the International Fire Code. 

[F] 513.18 Acceptance testing. Devices, equipment, compo- 
nents and sequences shall be tested in accordance with the In- 
ternational Fire Code. 

[F] 513.19 System acceptance. Acceptance of the smoke con- 
trol system shall be in accordance with the International Fire 
Code. 

[B] 513.20 Underground building smoke exhaust system. 

Where required by the International Building Code for under- 
ground buildings, a smoke exhaust system shall be provided in 
accordance with this section. 

[B] 513.20.1 Exhaust capability. Where compartmentation is 
required, each compartment shall have an independent, auto- 
matically activated smoke exhaust system capable of manual 
operation. The system shall have an air supply and smoke ex- 
haust capability that will provide a minimum of six air changes 
per hour. 

[F] 513.20.2 Operation. The smoke exhaust system shall 
be operated in accordance with the International Fire Code. 

[F] 513.20.3 Alarm required. Activation of the smoke ex- 
haust system shall activate an audible alarm at a constantly 
attended location in accordance with the International Fire 
Code. 



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EXHAUST SYSTEMS 



SECTION 514 
ENERGY RECOVERY VENTILATION SYSTEMS 

514.1 General. Energy recovery ventilation systems shall be 
installed in accordance with this section. Where required for 
purposes of energy conservation, energy recovery ventilation 
systems shall also comply with the International Energy Con- 
servation Code. 

514.2 Prohibited applications. Energy recovery ventilation 
systems shall not be used in the following systems: 

1. Hazardous exhaust systems covered in Section 510. 

2. Dust, stock and refuse systems that convey explosive or 
flammable vapors, fumes or dust. 

3. Smoke control systems covered in Section 513. 

4. Commercial kitchen exhaust systems serving Type I and 
Type II hoods. 

5. Clothes dryer exhaust systems covered in Section 504. 

514.3 Access. A means of access shall be provided to the heat 
exchanger and other components of the system as required for 
service, maintenance, repair or replacement. 



52 2003 INTERNATIONAL MECHANICAL CODE® 



CHAPTER 6 

DUCT SYSTEMS 



SECTION 601 
GENERAL 

601.1 Scope. Duct systems used for the movement of air in 
air-conditioning, heating, ventilating and exhaust systems shall 
conform to the provisions of this chapter except as otherwise 
specified in Chapters 5 and 7. 

Exception: Ducts discharging combustible material di- 
rectly into any combustion chamber shall conform to the re- 
quirements of NFPA 82. 

[B] 601.2 Air movement in egress elements. Exit access cor- 
ridors shall not serve as supply, return, exhaust, reUef or venti- 
lation air ducts. 

Exceptions: 

1 . Use of a corridor as a source of makeup air for exhaust 
systems in rooms that open directly onto such corri- 
dors, including toilet rooms, bathrooms, dressing 
rooms, smoking lounges and janitor closets, shall be 
permitted provided that each such corridor is directly 
supplied with outdoor air at a rate greater than the rate 
of makeup air taken from the corridor. 

2. Where located within a dwelling unit, the use of corri- 
dors for conveying return air shall not be prohibited. 

3. Where located within tenant spaces of 1,000 square 
feet (93 m^) or less in area, utilization of corridors for 
conveying return air is permitted. 

[B] 601.2.1 Corridor ceiling. Use of the space between the 
corridor ceiling and the floor or roof structure above as a re- 
turn air plenum is permitted for one or more of the following 
conditions: 

1. The corridor is not required to be of fire-resis- 
tance-rated construction; 

2. The corridor is separated from the plenum by fire-re- 
sistance-rated construction; 

3. The air-handling system serving the corridor is shut 
down upon activation of the air-handling unit smoke 
detectors required by this code; 

4. The air-handling system serving the corridor is shut 
down upon detection of sprinkler waterflow where the 
building is equipped throughout with an automatic 
sprinkler system; or 

5. The space between the corridor ceiling and the floor 
or roof structure above the corridor is used as a com- 
ponent of an approved engineered smoke control sys- 
tem. 

601.3 Contamination prevention. Exhaust ducts under posi- 
tive pressure, chimneys, and vents shall not extend into or pass 
through ducts or plenums. 



SECTION 602 
PLENUMS 

602.1 General. Supply, return, exhaust, relief and ventilation 
air plenums shall be limited to uninhabited crawl spaces, areas 
above a ceiling or below the floor, attic spaces and mechanical 
equipment rooms. Plenums shall be Hmited to one fire area. 
Fuel-fired appliances shall not be installed within a plenum. 

602.2 Construction. Plenujn enclosures shall be constructed 
of materials permitted for the type of construction classifica- 
tion of the building. 

The use of gypsum boards to form plenums shall be limited to 
systems where the air temperatures do not exceed 1 25 °F (52° C) 
and the building and mechanical system design conditions are 
such that the gypsum board surface temperature will be main- 
tained above the airstream dew-point temperature. Air plenums 
formed by gypsum boards shall not be incorporated in air-han- 
dling systems utilizing evapbrative coolers. 

602.2.1 Materials exposed within plenums. Except as re- 
quired by Sections 602.2.1.1 through 602.2.1.5, materials 
exposed within plenums shall be noncombustible or shall 
have a flame spread index of not more than 25 and a 
smoke-developed index of not more than 50 when tested in 
accordance with ASTM E 84. 

Exceptions: 

1 . Rigid and flexible ducts and connectors shall con- 
form to Section 603. 

2. Duct coverings^ linings, tape and connectors shall 
conform to Sections 603 and 604. 

3. This section shall not apply to materials exposed 
within plenums in one- and two-family dwellings. 

4. This section shall not apply to smoke detectors. 

5. Combustible materials enclosed in approved gyp- 
sum board assemblies or enclosed in materials 
listed and labeled for such application. 

602.2.1.1 Wiring. Combustible electrical or electronic 
wiring methods and materials, optical fiber cable, and 
optical fiber raceway exposed within a plenum shall have 
a peak optical density not greater than 0.50, an average 
opfical density not greater than 0.15, and a flame spread 
not greater than 5 feet (1524 mm) when tested in accor- 
dance with NFPA 262. Only type OFNP (plenum rated 
nonconductive optical fiber cable) shall be installed in 
plenum-rated optical fiber raceways. Wiring, cable, and 
raceways addressed iii this secdon shall be Usted and la- 
beled as plenum rated and shall be installed in accor- 
dance with ICC Electrical Code. 

602.2.1.2 Fire sprinkler piping. Plastic fire sprinkler pip- 
ing exposed within a plenum shall be used only in wet pipe 
systems and shall haye a peak optical density not greater 
than 0.50, an average optical density not greater than 0. 15, 



2003 INTERNATIONAL MECHANICAL CODE® 



53 



DUCT SYSTEMS 



and a flame spread of not greater than 5 feet (1524 mm) 
when tested in accordance with UL 1887. Piping shall be 
listed and labeled. 

602.2.1.3 Pneumatic tubing. Combustible pneumatic 
tubing exposed within a plenum shall have a peak optical 
density not greater than 0.50, an average optical density 
not greater than 0.15, and a flame spread of not greater 
than 5 feet (1524 mm) when tested in accordance with 
UL 1820. Combustible pneumatic tubing shall be listed 
and labeled. 

602.2.1.4 Combustible electrical equipment. Combus- 
tible electrical equipment exposed within a plenum shall 
have a peak rate of heat release not greater than 100 kilo- 
watts, a peak optical density not greater than 0.50 and an 
average optical density not greater than 0. 15 when tested 
in accordance with UL 2043. Combustible electrical 
equipment shall be listed and labeled. 

602.2.1.5 Foam plastic insulation. Foam plastic insula- 
tion used as wall or ceiling finish in plenums shall exhibit 
a flame spread index of 75 or less and a smoke-developed 
index of 450 or less when tested in accordance with 
ASTM E 84 and shall also comply with Section 
602.2.1.5.1, 602.2.1.5.2 or 602.2.1.5.3. 

602.2.1.5.1 Separation required. The foam plastic 
insulation shall be separated from the plenum by a 
thermal barrier complying with Section 2603.4 of the 
International Building Code. 

602.2.1.5.2 Approval. The foam plastic insulation 
shall be approved based on tests conducted in accor- 
dance with Section 2603.8 of the International Build- 
ing Code. 

602.2.1.5.3 Covering. The foam plastic insulation 
shall be covered by corrosion-resistant steel having a 
base metal thickness of not less than 0.0160 inch (0.4 
mm). 

602.3 Stud cavity and joist space plenums. Stud wall cavities 
and the spaces between solid floor joists to be utilized as air ple- 
nums shall comply with the following conditions: 

1. Such cavities or spaces shall not be utilized as a plenum 
for supply air. 

2. Such cavities or spaces shall not be part of a required 
fire-resistance-rated assembly. 

3. Stud wall cavifies shall not convey air from more than 
one floor level. 

4. Stud wall cavities and joist space plenums shall comply 
with the floor penetration protection requirements of the 
International Building Code. 

5. Stud wall cavities and joist space plenums shall be iso- 
lated from adjacent concealed spaces by approved 
fireblocking as required in the International Building 
Code. 

[B] 602.4 Flood hazard. For structures located in flood hazard 
areas, plenum spaces shall be located above the design flood ele- 
vation or shall be designed and constructed to prevent water 
from entering or accumulating within the plenum spaces during 
floods up to the design flood elevation. If the plenum spaces are 



located below the design flood elevation, they shall be capable of 
resisting hydrostatic and hydrodynamic loads and stresses, in- 
cluding the effects of buoyancy, during the occurrence of flood- I 
ing to the design flood elevation. 



SECTION 603 
DUCT CONSTRUCTION AND INSTALLATION 

603.1 General. An air distribution system shall be designed 
and installed to supply the required distribution of air. The in- 
stallation of an air distribution system shall not affect the fire 
protection requirements specified in the International Building 
Code. Ducts shall be constructed, braced, reinforced and in- 
stalled to provide structural strength and durability. 

603.2 Duct sizing. Ducts installed within a single dwelling 
unit shall be sized in accordance with ACC A Manual D or other 
approved methods. Ducts installed within all other buildings 
shall be sized in accordance with the ASHRAE Handbook of 
Fundamentals or other equivalent computation procedure. 

603.3 Duct classification. Ducts shall be classified based on 
the maximum operating pressure of the duct at pressures of 
positive or negative 0.5, 1.0, 2.0, 3.0, 4.0, 6.0 or 10.0 inches of 
water column. The pressure classification of ducts shall equal 
or exceed the design pressure of the air distribution in which the 
ducts are utilized. 

603.4 Metallic ducts. All metallic ducts shall be constructed as 
specified in the SMACNA HVAC Duct Construction Stan- 
dards — Metal and Flexible. 

Exception: Ducts installed within single dwelling units 
shall have a minimum thickness as specified in Table 603.4. 

TABLE 603.4 
DUCT CONSTRUCTION MINIMUM SHEET METAL 
THICKNESSES FOR SINGLE DWELLING UNITS 



DUCT SIZE 


GALVANIZED 


APPROXIMATE 

ALUMINUM B&S 

GAGE 


Minimum 
thickness 
(inches) 


Equivalent 

Galvanized 

Gage No. 


Round ducts and enclosed 
Rectangular ducts 

14" or less 

Over 14" 


0.013 
0.016 


30 

28 


26 
24 


Exposed rectangular ducts 
14" or less 
Over 14" 


0.016 
0.019 


28 
26 


24 

22 



For SI: 1 inch = 25.4 mm. 

603.5 Nonmetallic ducts. Nonmetallic ducts shall be con- 
structed with Class or Class 1 duct material in accordance with 
UL 181, Fibrous duct construction shall conform to the 
SMACNA Fibrous Glass Duct Construction Standards or 
NAIM A Fibrous Glass Duct Construction Standards. The maxi- 
mum air temperature within nonmetallic ducts shall not exceed 
250°F(12rC). 

603.5.1 Gypsum ducts. The use of gypsum boards to form 
air shafts (ducts) shall be limited to return air systems where 
the air temperatures do not exceed 125°F (52 °C) and the 
gypsum board surface temperature is maintained above the 



54 



2003 INTERNATIONAL MECHANICAL CODE® 



DUCT SYSTEMS 



airstream dew-point temperature. Air ducts formed by gyp- 
sum boards shall not be incorporated in air-handling sys- 
tems utilizing evaporative coolers. 

603.6 Flexible air ducts and flexible air connectors. Rexible 
air ducts, both metallic and nonmetallic, shall comply with Sec- 
tions 603.6.1, 603.6.1.1, 603.6.3 and 603.6.4. Hexible air con- 
nectors, both metallic and nonmetallic, shall comply with 
Sections 606.6.2 through 603.6.4. 

603.6.1 Flexible air ducts. Flexible air ducts, both metallic 
and nonmetallic, shall be tested in accordance with UL 181. 
Such ducts shall be listed and labeled as Class or Class 1 
flexible air ducts and shall be installed in accordance with 
Section 304.1. 

603.6.1.1 Duct length. Flexible air ducts shall not be 
limited in length. 

603.6.2 Flexible air connectors. Flexible air connectors, 
both metallic and nonmetallic, shall be tested in accordance 
with UL 181. Such connectors shall be Hsted and labeled as 
Class or Class 1 flexible air connectors and shall be in- 
stalled in accordance with Section 304.1. 

603.6.2.1 Connector length. Flexible air connectors 
shall be limited in length to 14 feet (4267 mm). 

603.6.2.2 Connector penetration limitations. Flexible 
air connectors shall not pass through any wall, floor or 
ceiling. 

603.6.3 Air temperature. The design temperature of air to 
be conveyed in flexible air ducts and flexible air connectors 
shall be less than 250°F (121 °C). 

603.6.4 Flexible air duct and air connector clearance. 

Flexible air ducts and air connectors shall be installed with a 
minimum clearance to an appliance as specified in the appli- 
ance manufacturer's installation instructions. 

603.7 Rigid duct penetrations. Duct system penetrations of 
walls, floors, ceilings and roofs and air transfer openings in 
such building components shall be protected as required by 
Section 607. 

603.8 Underground ducts. Ducts shall be approved for un- 
derground installation. Metallic ducts not having an approved 
protective coating shall be completely encased in a minimum 
of 2 inches (5 1 mm) of concrete. 

603.8.1 Slope. Ducts shall slope to allow drainage to a point 
provided with access. 

603.8.2 Sealing. Ducts shall be sealed and secured prior to 
pouring the concrete encasement. 

603.8.3 Plastic ducts and flttings. Plastic ducts shall be con- 
structed of PVC having a minimum pipe stiffness of 8 psi (55 
kPa) at 5-percent deflection when tested in accordance with 
ASTM D 2412. Plastic duct fittings shall be constructed of ei- 
ther PVC or high-density polyethylene. Plastic duct and fit- 
tings shall be utilized in underground installations only. The 
maximum design temperature for systems utilizing plastic 
duct and fittings shall be 150°F (66X). 

603.9 Joints, seams and connections. All longitudinal and 
transverse joints, seams and connections in metallic and non- 
metallic ducts shall be constructed as specified in SMACNA 



HVAC Duct Construction Standards — Metal and Flexible and 
SMACNA Fibrous Glass Duct Construction Standards or 
NAIMA Fibrous Glass Duct Construction Standards. All lon- 
gitudinal and transverse joints, seams and connections shall be 
sealed in accordance with the International Energy Conserva- 
tion Code. 

603.10 Supports. Ducts shall be supported with approved 
hangers at intervals not exceeding 10 feet (3048 mm) or by 
other approved duct support systems designed in accordance 
with the International Building Code, Flexible and other fac- 
tory-made ducts shall be supported in accordance with the 
manufacturer's installation instructions. 

603.11 Furnace connections. Ducts connecting to a furnace 
shall have a clearance to combustibles in accordance with the 
furnace manufacturer's installation instructions. 

603.12 Condensation. Provisions shall be made to prevent the 
formation of condensation on the exterior of any duct. 

[B] 603.13 Flood hazard areas. For structures in flood hazard 
areas, ducts shall be located above the design flood elevation or 
shall be designed and constructed to prevent water from entering 
or accumulating within the ducts during floods up to the design 
flood elevation. If the ducts are located below the design flood 
elevation, the ducts shall be capable of resisting hydrostatic and 
hydrodynamic loads and stresses, including the effects of buoy- 
ancy, during the occurrence of flooding to the design flood ele- 
vation. 

603.14 Location. Ducts shall not be installed in or within 4 
inches (102 mm) of the earth, except where such ducts comply 
with Section 603.8. 

603.15 Mechanical protection. Ducts installed in locations 
where they are exposed to mechanical damage by vehicles or 
from other causes shall be protected by approved barriers. 

603.16 Weather protection. All ducts including linings, cov- 
erings and vibration isolation connectors installed on the exte- 
rior of the building shall be adequately protected against the 
elements. 

603.17 Registers, grilles and diffusers. Duct registers, grilles 
and diffusers shall be installed in accordance with the manufac- 
turer's installation instructions. Balancing dampers or other 
means of supply air adjustment shall be provided in the branch 
ducts or at each individual duct register, grille or diffuser. 

603.17.1 Floor registers. Floor registers shall resist, with- 
out structural failure, a 200-pound (90.8 kg) concentrated 
load on a 2-inch-diameter (51 nam) disc applied to the most 
critical area of the exposed face. 



SECTION 604 
INSULATION 

604.1 General. Duct insulation shall conform to the require- 
ments of Sections 604.2 through 604.13 and the International 
Energy Conservation Code. 

604.2 Surface temperature. Ducts that operate at temperatures 
exceeding 120°F (49 °C) shall have sufficient thermal insulation 
to limit the exposed surface temperature to 120 ""F (49 °C). 



2003 INTERNATIONAL MECHANICAL CODE® 



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DUCT SYSTEMS 



604.3 Coverings and linings. Coverings and linings, including 
adhesives when used, shall have a flame spread index not more 
than 25 and a smoke-developed index not more than 50, when 
tested in accordance with ASTM E 84. Duct coverings and lin- 
ings shall not flame, glow, smolder or smoke when tested in ac- 
cordance with ASTM C 41 1 at the temperature to which they 
are exposed in service. The test temperature shall not fall below 
250°F(12rC). 

604.4 Foam plastic insulation. Foam plastic used as duct cov- 
erings and linings shall conform to the requirements of Section 

I 604. 

604.5 Appliance insulation. Listed and labeled appliances that 
are internally insulated shall be considered as conforming to the 
requirements of Section 604. 

604.6 Penetration of assemblies. Duct coverings shall not pen- 
etrate a wall or floor required to have a fire-resistance rating or 
required to be fireblocked. 

[EC] 604.7 Identification. External duct insulation and fac- 
tory-insulated flexible duct shall be legibly printed or identi- 
fied at intervals not greater than 36 inches (914 mm) with the 
name of the manufacturer, the thermal resistance /?- value at the 
specified installed thickness and the flame spread and 
smoke-developed indexes of the composite materials. All duct 
insulation product /^-values shall be based on insulation only, 
excluding air films, vapor retarders or other duct components, 
and shall be based on tested C- values at 75 °F (24°C) mean 
temperature at the installed thickness, in accordance with rec- 
ognized industry procedures. The installed thickness of duct 
insulation used to determine its /?- values shall be determined as 
follows: 

1 . For duct board, duct liner and factory-made rigid ducts 
not normally subjected to compression, the nominal in- 
sulation thickness shall be used. 

2. For duct wrap, the installed thickness shall be assumed to 
be 75 percent (25-percent compression) of nominal 
thickness. 

3. For factory-made flexible air ducts, the installed thick- 
ness shall be determined by dividing the difference be- 
tween the actual outside diameter and nominal inside 
diameter by two. 

604.8 Lining installation. Linings shall be interrupted at the 
area of operation of a fire damper and at a minimum of 6 inches 
(152 mm) upstream of and 6 inches (152 mm) downstream of 
electric-resistance and fuel-burning heaters in a duct system. 
Metal nosings or sleeves shall be installed over exposed duct 
liner edges that face opposite the direction of airflow. 

604.9 Thermal continuity. Where a duct liner has been inter- 
rupted, a duct covering of equal thermal performance shall be 
installed. 

604.10 Service openings. Service openings shall not be con- 
cealed by duct coverings unless the exact location of the open- 
ing is properly identified. 

604.11 Vapor retarders. Where ducts used for cooling are ex- 
ternally insulated, the insulation shall be covered with a vapor 
retarder having a maximum permeance of 0.05 perm [2.87 
ng/(Pa • s • m^)] or aluminum foil having a minimum thickness 
of 2 mils (0.051 mm). Insulations having a permeance of 0.05 



perm [2.87 ng/(P • s • m^ )] or less shall not be required to be 
covered. All joints and seams shall be sealed to maintain the 
continuity of the vapor retarder. 

604.12 Weatherproof barriers. Insulated exterior ducts shall 
be protected with an approved weatherproof barrier. 

604.13 Internal insulation. Materials used as internal insula- 
tion and exposed to the airstream in ducts shall be shown to be 
durable when tested in accordance with UL 181. Exposed inter- 
nal insulafion that is not impermeable to water shall not be used 
to line ducts or plenums from the exit of a cooling coil to the 
downstream end of the drain pan. 



SECTION 605 
AIR FILTERS 

605.1 General. Heating and air-conditioning systems of the cen- 
tral type shall be provided with approved air filters. Filters shall 
be installed in the return air system, upstream from any heat 
exchanger or coil, in an approved convenient location. Liquid 
adhesive coatings used on filters shall have a flash point not 
lower than 325 °F (163 °C). 

605.2 Approval. Media-type and electrostatic-type air filters 
shall be listed and labeled. Media-type air filters shall comply 
with UL 900. High efficiency particulate air filters shall com- 
ply with UL 586. Electrostatic-type air filters shall comply 
with UL 867. Air filters utilized within dwelling units shall be 
designed for the intended application and shall not be required 
to be listed and labeled. 

605.3 Airflow over the filter. Ducts shall be constructed to al- 
low an even distribution of air over the entire filter. 



SECTION 606 
SMOKE DETECTION SYSTEMS CONTROL 

606.1 Controls required. Air distribution systems shall be 
equipped with smoke detectors listed and labeled for installation 
in air distribution systems, as required by this section. 

606.2 Where required. Smoke detectors shall be installed 
where indicated in Sections 606.2.1 through 606.2.3. 

Exception: Smoke detectors shall not be required where air 
distribution systems are incapable of spreading smoke be- 
yond the enclosing walls, floors and ceilings of the room or 
space in which the smoke is generated. 

606.2.1 Return air systems. Smoke detectors shall be in- 
stalled in return air systems with a design capacity greater 
than 2,000 cfm (0.9 mVs), in the return air duct or plenum 
upstream of any filters, exhaust air connections, outdoor air 
connections, or decontamination equipment and appliances. 

Exception: Smoke detectors are not required in the return 
air system where all portions of the building served by the 
air distribution system are protected by area smoke detec- 
tors connected to a fire alarm system in accordance with 
the International Fire Code. The area smoke detection 
system shall comply with Section 606.4. 

606.2.2 Common supply and return air systems. Where 
multiple air-handling systems share common supply or re- 
turn air ducts or plenums with a combined design capacity 



56 



2003 INTERNATIONAL MECHANICAL CODE® 



DUCT SYSTEMS 



greater than 2,000 cfm (0,9 mVs), the return air system shall 
be provided with smoke detectors in accordance with Sec- 
tion 606.2.1. 

Exception: Individual smoke detectors shall not be re- 
quired for each fan-powered terminal unit, provided that 
such units do not have an individual design capacity 
greater than 2,000 cfm (0.9 m /s) and will be shut down 
by activation of one of the following: 

1 . Smoke detectors required by Sections 606.2. 1 and 
606.2.3. 

2. An approved area smoke detector system located 
in the return air plenum serving such units. 

3 . An area smoke detector system as prescribed in the 
exception to Section 606.2.1. 

In all cases, the smoke detectors shall comply with Sec- 
tions 606.4 and 606.4.1. 

606.2.3 Return air risers. Where return air risers serve two 
or more stories and serve any portion of a return air system 
having a design capacity greater than 15,000 cfm (7.1 mVs), 
smoke detectors shall be installed at each story. Such smoke 
detectors shall be located upstream of the connection be- 
tween the return air riser and any air ducts or plenums. 

606.3 Installation. Smoke detectors required by this section 
shall be installed in accordance with NFPA 72. The required 
smoke detectors shall be installed to monitor the entire airflow 
conveyed by the system including return air and exhaust or re- 
lief air. Access shall be provided to smoke detectors for inspec- 
tion and maintenance. 

606.4 Controls operation. Upon activation, the smoke detec- 
tors shall shut down the air distribution system. Air distribution 
systems that are part of a smoke control system shall switch to 
the smoke control mode upon activation of a detector. 

606.4.1 Supervision. The duct smoke detectors shall be con- 
nected to a fire alarm system. The actuation of a duct smoke 
detector shall activate a visible and audible supervisory signal 
at a constantly attended location. 

Exceptions: 

1. The supervisory signal at a constantly attended lo- 
cation is not required where the duct smoke detec- 
tor activates the building's alarm-indicating 
appliances. 

2. In occupancies not required to be equipped with a 
fire alarm system, actuation of a smoke detector 
shall activate a visible and an audible signal in an 
approved location. Duct smoke detector trouble 
conditions shall acfivate a visible or audible signal 
in an approved location and shall be identified as 
air duct detector trouble. 



[B] SECTION 607 
DUCTS AND AIR TRANSFER OPENINGS 

607.1 General. The provisions of this section shall govern the 
protection of duct penetrations and air transfer openings in 
fire-resistance-rated assembhes. 



607.1.1 Ducts and air transfer openings without dampers. 

Ducts and air transfer openings that penetrate fire-resis- 
tance-rated assemblies and are not required to have dampers 
by this section shall comply with the requirements of Section 
712 of the International Building Code. 

607.2 Installation. Fire dampers, smoke dampers, combina- 
tion fire/smoke dampers and ceiling dampers located within air 
distribution and smoke control systems shall be installed in ac- 
cordance with the requirements of this section, and the 
manufacturer's installation instructions and listing. 

607.2.1 Smoke control system. Where the installation of a 
fire damper will interfere with the operation of a required 
smoke control system in accordance with Section 513, ap- 
proved alternative protection shall be utilized. 

607.2.2 Hazardous exhaust ducts. Fire dampers for haz- 
ardous exhaust duct systems shall comply with Section 510. 

607.3 Damper testing and ratings. Dampers shall be listed and 
bear the label of an approved testing agency indicating compli- 
ance with the standards in this section. Fire dampers shall com- 
ply with the requirements of UL 555. Only fire dampers labeled 
for use in dynamic systems shall be installed in heating, ventila- 
tion and air-conditioning systems designed to operate with fans 
on during a fire. Smoke dampers shall comply with the require- 
ments of UL 555S. Combination fire/smoke dampers shall com- 
ply with the requirements of both UL 555 and UL 555S. Ceihng 
radiation dampers shall comply with the requirements of UL 
555C. 

607.3.1 Fire protection rating. Fire dampers shall have the 
minimum fire protection rating specified in Table 607.3.1 
for the type of penetration. 

TABLE 607.3.1 
FIRE DAMPER RATING 



TYPE OF PENETRATION 


MINIMUM DAMPER 
RATING (hour) 


Less than 3-hour fire-resistance-rated 
assemblies 


IV, 


3 -hour or greater fire-resistance-rated 
assembles > 


3 



607.3.1.1 Fire damper actuating device. The fire 
damper actuating device shall meet one of the following 
requirements: 

1 . The operating temperature shall be approximately 
50°F (27.8 °C) above the normal temperature 
within the duct system, but not less than 160''F 
(71 °C). 

2. The operating temperature shall be not more than 
286°F (141 °C) where located in a smoke control 
system complying with Section 513. 

3. Where a combination fire/smoke damper is lo- 
cated in a smoke control system complying with 
Section 5 13, the operating temperature rating shall 
be approximately 50°F (27.8 °C) above the maxi- 
mum smoke control system designed operating 
temperature, or a maximum temperature of 350 °F 



2003 INTERNATIONAL MECHANICAL CODE® 



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DUCT SYSTEMS 



(177°C). The temperature shall not exceed the UL 
555S degradation test temperature rating for a 
combination fire/smoke damper. 

607.3.2 Smoke damper ratings. Smoke damper leakage 
ratings shall not be less than Class II. Elevated temperature 
ratings shall be not less than 250°F (121°C). 

607.3.2.1 Smoke damper actuation methods. The 

smoke damper shall close upon actuation of a listed 
smoke detector or detectors installed in accordance with 
Section 607 of this code and Sections 907. 10 and 907.1 1 
of the International Building Code and one of the follow-, 
ing methods, as applicable: 

1 . Where a damper is installed within a duct, a smoke 
detector shall be installed in the duct within 5 feet 
(1524 mm) of the damper with no air outlets or in- 
lets between the detector and the damper. The de- 
tector shall be listed for the air velocity, 
temperature and humidity anticipated at the point 
where it is installed. Other than in mechanical 
smoke control systems, dampers shall be closed 
upon fan shutdown where local smoke detectors 
require a minimum velocity to operate. 

2. Where a damper is installed above smoke barrier 
doors in a smoke barrier, a spot-type detector listed 
for releasing service shall be installed on either 
side of the smoke barrier door opening. 

3. Where a damper is installed within an unducted 
opening in a wall, a spot-type detector listed for re- 
leasing service shall be installed within 5 feet 
(1524 mm) horizontally of the damper. 

4. Where a damper is installed in a corridor wall, the 
damper shall be permitted to be controlled by a 
smoke detection system installed in the corridor. 

5. Where a total-coverage smoke detector system is 
provided within areas served by an HVAC system, 
dampers shall be permitted to be controlled by the 
smoke detection system. 

607.4 Access and identification. Fire and smoke dampers shall 
be provided with an approved means of access, large enough to 
permit inspection and maintenance of the damper and its operat- 
ing parts. The access shall not affect the integrity of 
frre-resistance-rated assemblies. The access openings shall not 
reduce the fire-resistance rating of the assembly. Access points 
shall be permanently identified on the exterior by a label having 
letters not less than 0.5 inch (12.7 mm) in height reading: 
SMOKE DAMPER or HRE DAMPER. Access doors in ducts 
shall be tight fitting and suitable for the required duct construc- 
tion. 

607.5 Where required. Fire dampers, smoke dampers, combi- 
nation fire/smoke dampers and ceiling radiation dampers shall 
be provided at the locations prescribed in this section. Where an 
assembly is required to have both fire dampers and smoke damp- 
ers, combinafion fire/smoke dampers or a fire damper and a 
smoke damper shall be required. 

607.5.1 Fire walls. Ducts and air transfer openings permit- 
ted in fire walls in accordance with Section 705. 1 1 of the In- 



ternational Building Code shall be protected with approved 
fire dampers installed in accordance with their hsUng. 

607.5.2 Fire barriers. Duct penetrations and air transfer 
openings in fire barriers shall be protected with approved 
fire dampers installed in accordance with their fisting. 

Exceptions: Fire dampers are not required at penetra- 
tions of fire barriers where any of the following apply: 

1 . Penetrations are tested in accordance with ASTM 
E 119 as part of the fire-resistance-rated assembly. 

2. Ducts are used as part of an approved smoke con- 
trol system in accordance with Section 513. 

3. Such walls are penetrated by ducted HVAC sys- 
tems, have a required fire-resistance rating of 1 
hour or less, are in areas of other than Group H and 
are in buildings equipped throughout with an auto- 
matic sprinkler system in accordance with Section 
903.3.1.1 or 903.3.1.2 of the International Build- 
ing Code. For the purposes of this exception, a 
ducted HVAC system shall be a duct system for the 
structure's HVAC system. Such a duct system 
shall be constructed of sheet metal not less than 
26-gage (0.0217 inch) [0.55 mm] thickness and 
shall be continuous from the air-handling appH- 
ance or equipment to the air outlet and inlet termi- 
nals. 

607.5.3 Fire partitions. Duct penetrations in fire partitions 
shall be protected with approved fire dampers installed in 
accordance with their listing. 

Exceptions: In occupancies other than Group H, fire damp- 
ers are not required where any of the following apply: 

1. The partitions are tenant separation and corridor 
walls in buildings equipped throughout with an au- 
tomatic sprinkler system in accordance with Sec- 
tion 903.3.1.1 or 903.3.1.2 of the International 
Building Code and the duct is protected as a 
through penetration in accordance with the Inter- 
national Building Code. 

2. The duct system is constructed of approved materi- 
als in accordance with this code and the duct pene- 
trating the wall meets all of the following 
minimum requirements. 

2.1. The duct shall not exceed 100 square 
inches (0.06 m^). 

2.2. The duct shall be constructed of steel a 
minimum of 0.0217-inch (0.55 mm) in 
thickness. 

2.3. The duct shall not have openings that com- 
municate the corridor with adjacent spaces 
or rooms. 

2.4. The duct shall be installed above a ceiling. 

2.5. The duct shall not terminate at a wall regis- 
ter in the fire-resistance-rated wall. 

2.6. A minimum 12-inch-long (3048 mm) by 
0.060-inch-thick (0.52 mm) steel sleeve 
shall be centered in each duct opening. The 



58 



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DUCT SYSTEMS 



sleeve shall be secured to both sides of the 
wall and all four sides of the sleeve with 
minimum lV2-inch by 1 Vs-inch by 
0.060-inch (38 mm by 38 mm by 1.52 mm) 
steel retaining angles. The retaining angles 
shall be secured to the sleeve and the wall 
with No. 10 (M5) screws. The annular 
space between the steel sleeve and the wall 
opening shall be filled with rock (mineral) 
wool batting on all sides. 

607.5.4 Corridors/smoke barriers. A listed smoke damper 
designed to resist the passage of smoke shall be provided at 
each point a duct or air transfer opening penetrates a smoke 
barrier wall or a corridor enclosure required to have smoke 
and draft control doors in accordance with the International 
Building Code, Smoke dampers and smoke damper actuation 
methods shall comply with Section 607.5.4.1. 

Exceptions: 

1 . Smoke dampers are not required in corridor pene- 
trations where the building is equipped throughout 
with an approved smoke control system in accor- 
dance with Section 513 and smoke dampers are not 
necessary for the operation and control of the sys- 
tem. 

2. Smoke dampers are not required in smoke barrier 
penetrations where the openings in ducts are lim- 
ited to a single smoke compartment and the ducts 
are constructed of steel. 

3. Smoke dampers are not required in corridor pene- 
trations where the duct is constructed of steel not 
less than 0.019 inch (0.48 mm) in thickness and 
there are no openings serving the corridor. 

607.5.4.1 Smoke damper. The smoke damper shall 
close upon actuation of a listed smoke detector or detec- 
tors installed in accordance with the International Build- 
ing Code and one of the following methods, as 
applicable: 

1 . Where a damper is installed within a duct, a smoke 
detector shall be installed in the duct within 5 feet 
(1524 mm) of the damper with no air outlets or in- 
lets between the detector and the damper. The de- 
tector shall be listed for the air velocity, 
temperature and humidity anticipated at the point 
where it is installed. 

2. Where a damper is installed above smoke barrier 
doors in a smoke barrier, a spot-type detector listed 
for releasing service shall be installed on either 
side of the smoke barrier door opening. 

3. Where a damper is installed within an unducted 
opening in a wall, a spot-type detector listed for re- 
leasing service shall be installed within 5 feet 
(1524 mm) horizontally of the damper. 

4. Where a damper is installed in a corridor wall, the 
damper shall be permitted to be controlled by a 
smoke detection system installed in the corridor. 

5. Where a total-coverage smoke detector system is 
provided within all areas served by an HVAC sys- 



tem, dampers sljall be permitted to be controlled 
by the smoke detection system. 

607.5.5 Shaft enclosures. Ducts and air transfer openings 
shall not penetrate a shaft serving as an exit enclosure except 
as permitted by Section 1 1 9. 1 .2 of the International Build- 
ing Code. 

607.5.5.1 Penetrations of siiaft enclosures. Shaft en- 
closures that are permitted to be penetrated by ducts and 
air transfer openings shall be protected with approved 
fire and smoke dampers installed in accordance with 
their Hsting. 

Exceptions: 

1 . Fire dampers are not required at penetrations of 
shafts where: 

1.1. Steel exhaust subducts extend at least 
22 inches (559 mm) vertically in ex- 
haust shafts provided there is a continu- 
ous airflow upward to the outside; or 

1.2. Penetrations are tested in accordance 
with ASTM E 1 19 as part of the fire-re- 
sistance-rated assembly; 

1.3. Ducts are used as part of an approved 
smoke control system designed and in- 
stalled in accordance with Section 909 
of the International Building Code, and 
where the fire damper will interfere 
with the operation of the smoke control 
system; or 

1.4. The penetrations are in parking garage 
exhaust or supply shafts that are sepa- 
rated from other building shafts by not 
less than 2-hour fire-resistance-rated 
construction. 

2. In Group B occupancies, equipped throughout 
with an automatic sprinkler system in accor- 
dance with Section 903.3.1.1 of the Interna- 
tional Building Code, smoke dampers are not 
required at penetrations of shafts where: 

2.1. Bathroom and toilet room exhaust 
openings with steel exhaust subducts, 
having a wall thickness of at least 0.019 
inch (0.48 mm) extend at least 22 inches 
(55^ mm) vertically and the exhaust fan 
at the upper terminus is powered contin- 
uously in accordance with the provi- 
sions of Section 909.11 of the 
International Building Code^ and main- 
tainS airflow upward to the outside, or 

2.2. Ducts are used as part of an approved 
smoke control system designed and in- 
stalled in accordance with Section 909 
of the International Building Code, and 
whqre the smoke damper will interfere 
with the operation of the smoke control 
system. 



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3. Smoke dampers are not required at penetration 
of exhaust or supply shafts in parking garages 
that are separated from other building shafts by 
not less than 2-hour llre-resistance-rated con- 
struction. 

607.6 Horizontal assemblies. Penetrations by air ducts of a 
floor, floor/ceiling assembly or the ceiling membrane of a 
roof/ceiling assembly shall be protected by a shaft enclosure 
that complies with the International Building Code or shall 
comply with this section. 

607.6.1 Through penetrations. In occupancies other than 
Groups 1-2 and 1-3, a duct and air transfer opening system 
constructed of approved materials in accordance with this 
code that penetrates a fire-resistance-rated floor/ceiling as- 
sembly that connects not more than two stories is permitted 
without shaft enclosure protection provided a fire damper is 
installed at the floor line. 

Exception: A duct is permitted to penetrate three floors 
or less without a fire damper at each floor provided it 
meets all of the following requirements. 

1 . The duct shall be contained and located within the 
cavity of a wall and shall be constructed of steel not 
less than 0.019 inch (0.48 mm) (26 gauge) in thick- 
ness. 

2. The duct shall open into only one dwelling unit or 
sleeping unit and the duct system shall be continu- 
ous from the unit to the exterior of the building. 

3. The duct shall not exceed 4-inch (102 mm) nomi- 
nal diameter and the total area of such ducts shall 
not exceed 100 square inches (64 5 16 mm^) for any 
100 square feet (9.3 m^) of the floor area. 

4. The annular space around the duct is protected 
with materials that prevent the passage of flame 
and hot gases sufficient to ignite cotton waste 
where subjected to ASTM E 1 19 time-temperature 
conditions under a minimum positive pressure dif- 
ferential of 0.01 inch (2.49 Pa) of water at the loca- 
tion of the penetration for the time period 
equivalent to the fire-resistance rating of the con- 
struction penetrated. 

5. Grille openings located in a ceiling of a fire-resis- 
tance-rated floor/ceiling or roof/ceiling assembly 
shall be protected with a ceiling radiation damper 
in accordance with Section 607.6.2. 

607.6.2 Membrane penetrations. Where duct systems con- 
structed of approved materials in accordance with this code 
penetrate a ceiling of a fire-resistance-rated floor/ceiling or 
roof/ceiling assembly, shaft enclosure protection is not re- 
quired provided an approved ceiling radiation damper is in- 
stalled at the ceiling line. Where a duct is not attached to a 
diffuser that penetrates a ceiling of a fire-resistance-rated 
floor/ceiling or roof/ceiling assembly, shaft enclosure protec- 
tion is not required provided an approved ceiling radiation 
damper is installed at the ceiling line. Ceiling radiation damp- 
ers shall be installed in accordance with UL 555C and con- 
structed in accordance with the details listed in a 
frre-resistance-rated assembly or shall be labeled to function 



as a heat barrier for air-handling outlet/inlet penetrations in 
the ceiling of a fu*e-resistance-rated assembly. Ceiling radia- 
tion dampers shall not be required where ASTM E 119 fu-e 
tests have shown that ceiUng radiation dampers are not neces- 
sary in order to maintain the fire-resistance rating of the as- 
sembly. Ceiling radiation dampers shall not be required 
where exhaust duct penetrations are protected in accordance 
with Section 7 12.4.2 of the International Building Code and 
the exhaust ducts are located within the cavity of a wall and do 
not pass through another dwelhng unit or tenant space. 

607.6.3 Nonfire-resistance-rated assemblies. Duct systems 
constructed of approved materials in accordance with this 
code that penetrate nonfire-resistance-rated floor assembhes 
that connect not more than two stories are permitted without 
shaft enclosure protection provided that the annular space be- 
tween the assembly and the penetrating duct is filled with an 
approved noncombustible material to resist the free passage 
of flame and the products of combustion. Duct systems con- 
structed of approved materials in accordance with this code 
that penetrate non-rated floor assembhes that connect not 
more than three stories are permitted without shaft enclosure 
protection provided that the annular space between the as- 
sembly and the penetrating duct is filled with an approved 
noncombustible material to resist the free passage of flame 
and the products of combustion, and a fire damper is installed 
at each floor line. 

Exception: Fire dampers are not required in ducts within 
individual residential dwelling units. 

607.7 Flexible ducts and air connectors. Flexible ducts and air 
connectors shall not pass through any fire-resistance-rated as- I 
sembly. ' 



60 



2003 INTERNATIONAL MECHANICAL CODE® 



CHAPTER 7 

COMBUSTION AIR 



SECTION 701 
GENERAL 

701.1 Scope. The provisions of this chapter shall govern the re- 
quirements for combustion and dilution air for fuel-burning ap- 
pliances other than gas-fired appliances. The requirements for 
combustion and dilution air for gas-fired appliances shall be in 
accordance with the International Fuel Gas Code, 

701.2 Combustion and dilution air required. Every room or 
space containing fuel-burning appliances shall be provided 
with combustion and dilution air as required by this code. Com- 
bustion and dilution air shall be provided in accordance with 
Section 702, 703, 704, 705, 706 or 707 or shall be provided by 
an approved engineered system. Direct vent appliances or 
equipment that do not draw combustion air from inside of the 
building are not required to be considered in the determination 
of the combustion and dilution air requirements. Combustion 
air requirements shall be determined based on the simultaneous 
operation of all fuel-burning appliances drawing combustion 
and dilution air from the room or space. 

701.3 Circulation of air. The equipment and appliances within 
every room containing fuel-burning appliances shall be in- 
stalled so as to allow free circulation of air. Provisions shall be 
made to allow for the simultaneous operation of mechanical ex- 
haust systems, fireplaces or other equipment and appliances 
operating in the same room or space from which combustion 
and dilution air is being drawn. Such provisions shall prevent 
the operation of such appliances, equipment and systems from 
affecting the supply of combustion and dilution air. 

701.4 Crawl space and attic space. For the purposes of this 
chapter, an opening to a naturally ventilated crawl space or attic 
space shall be considered equivalent to an opening to the out- 
doors. 

701.4.1 Crawl space. Where lower combustion air open- 
ings connect with crawl spaces, such spaces shall have un- 
obstructed openings to the outdoors at least twice that 
required for the combustion air openings. The height of the 
crawl space shall comply with the requirements of the Inter- 
national Building Code and shall be without obstruction to 
the free flow of air. 

701.4.2 Attic space. Where combustion air is obtained from 
an attic area, the attic ventilating openings shall not be sub- 
ject to ice or snow blockage, and the attic shall have not less 
than 30 inches (762 mm) vertical clear height at its maxi- 
mum point. Attic ventilation openings shall be sufficient to 
provide the required volume of combustion air and the attic 
ventilation required by the International Building Code. 
The combustion air openings shall be provided with a sleeve 
of not less than 0.019-inch (0.5 mm) (No. 26 Gage) galva- 
nized steel or other approved material extending from the 
appliance enclosure to at least 6 inches (152 mm) above the 
top of the ceiling joists and insulation. 



701.5 Prohibited sources. Openings and ducts shall not connect 
appliance enclosures with a space in which the operation of a fan 
will adversely affect the flow of the combustion air. Combustion 
air shall not be obtained from a hazardous location, except where 
the fuel-fired appliances are located within the hazardous loca- 
tion and are installed in accordance with this code. Combustion 
air shall not be taken from a refrigeration machinery room, ex- 
cept where a refrigerant vapbr detector system is installed to au- 
tomatically shut off the combustion process in the event of 
refrigerant leakage. Combustion air shall not be obtained from 
any location below the design flood elevation. 



SECTION 702 
INSIDE AIR 

702.1 All air from indoor^. Combustion and dilution air shall 
be permitted to be obtained entirely from the indoors in build- 
ings that are not of unusually tight construction. In buildings of 
unusually tight construction, combustion air shall be obtained 
from the outdoors in accordance with Section 703, 705, 706 or 
707, 

702.2 Air from the same room or space. The room or space 
containing fuel-burning appliances shall be an unconfmed 
space as defined in Section 202. 

702.3 Air from adjacent spaces. Where the volume of the 
room in which the fuel-burning appliances are located does not 
comply with Section 702.2, additional inside combustion and 
dilution air shall be obtained by opening the room to adjacent 
spaces so that the combined volume of all communicating 
spaces meets the volumetric requirement of Section 702.2. 
Openings connecting the spaces shall comply with Sections 
702.3.1 and 702.3.2. 

702.3.1 Number and location of openings. Two openings 
shall be provided, one within 1 foot (305 mm) of the ceiling 
of the room and one within 1 foot (305 mm) of the floor. 

702.3.2 Size of openings. The net free area of each opening, 
calculated in accordance with Section 708, shall be a mini- 
mum of 1 square inch per 1 ,000 Btu/h (220 1 mm^/kW) of in- 
put rating of the fuel-burning appliances drawing 
combustion and dilution air from the communicating spaces 
and shall be not less than 100 square inches (64 5 1 6 mm^). 



SECTION 703 
OUTDOOR AIR 

703.1 All air from the outdoors. Where all combustion and di- 
lution air is to be provided by outdoor air, the required combus- 
tion and dilution air shall be obtained by opening the room to 
the outdoors. Openings connecting the room to the outdoor air 
shall comply with Sections 703.1.1 through 703.1.4. 



2003 INTERNATIONAL MECHANICAL CODE® 



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703.1.1 Number and location of openings. Two openings 
shall be provided, one within 1 foot (305 mm) of the ceiling 
of the room and one within 1 foot (305 mm) of the floor. 

703.1.2 Size of direct openings. The net free area of each di- 
rect opening to the outdoors, calculated in accordance with 
Section 709, shall be a minimum of 1 square inch per 4,000 
Btu/h (550 mm^/kW) of combined input rating of the 
fuel-burning appliances drawing combustion and dilution air 
from the room. 

703.1.3 Size of horizontal openings. The net free area of 
each opening, calculated in accordance with Section 709 
and connected to the outdoors through a horizontal duct, 
shall be a minimum of 1 square inch per 2,000 Btu/h (1 100 
mm^/kW) of combined input rating of the fuel-burning ap- 
pliances drawing combustion and dilution air from the 
room. The cross-sectional area of the duct shall be equal to 
or greater than the required size of the opening. 

703.1.4 Size of vertical openings. The net free area of each 
opening, calculated in accordance with Section 709 and 
connected to the outdoors through a vertical duct, shall be a 
minimum of 1 square inch per 4,000 Btu/h (550 mm^/kW) 
of combined input rating of the fuel-burning appHances 
drawing combustion and dilution air from the room. The 
cross-sectional area of the duct shall be equal to or greater 
than the required size of the opening. 



SECTION 704 

COMBINED USE OF INSIDE AND OUTDOOR AIR 

(CONDITION 1) 

704.1 Combination of air from inside and outdoors. This 
section shall apply only to appliances located in confined 
spaces in buildings not of unusually tight construction. Where 
the volumes of rooms and spaces are combined for the purpose 
of providing indoor combustion air, such rooms and spaces 
shall communicate through permanent openings in compliance 
with Sections 702.3.1 and 702.3.2. The required combustion 
and dilution air shall be obtained by opening the room to the 
outdoors using a combination of inside and outdoor air, 
prorated in accordance with Section 704.1.6. The ratio of inte- 
rior spaces shall comply with Section 704, 1 .5. The number, lo- 
cation and ratios of openings connecting the space with the 
outdoor air shall comply with Sections 704.1.1 through 
704.1.4. 

704.1.1 Number and location of openings. At least two 
openings shall be provided, one within 1 foot (305 mm) of 
the ceiling of the room and one within 1 foot (305 mm) of 
the floor. 

704.1.2 Ratio of direct openings. Where direct openings to 
the outdoors are provided in accordance with Section 703. 1 , 
the ratio of direct openings shall be the sum of the net free 
areas of both direct openings to the outdoors, divided by the 
sum of the required areas for both such openings as deter- 
mined in accordance with Section 703.1.2. 

704.1.3 Ratio of horizontal openings. Where openings 
connected to the outdoors through horizontal ducts are pro- 
vided in accordance with Section 703.1, the ratio of hori- 
zontal openings shall be the sum of the net free areas of both 



such openings, divided by the sum of the required areas for 
both such openings as determined in accordance with Sec- 
tion 703.1.3. 

704.1.4 Ratio of vertical openings. Where openings con- 
nected to the outdoors through vertical ducts are provided in 
accordance with Section 703.1, the ratio of vertical open- 
ings shall be the sum of the net free areas of both such open- 
ings, divided by the sum of the required areas for both such 
openings as determined in accordance with Section 703 .1.4. 

704.1.5 Ratio of interior spaces. The ratio of interior 
spaces shall be the available volume of all communicating 
spaces, divided by the required volume as determined in ac- 
cordance with Sections 702.2 and 702.3. 

704.1.6 Prorating of inside and outdoor air. In spaces that 
utilize a combination of inside and outdoor air, the sum of 
the ratios of all direct openings, horizontal openings, verti- 
cal openings and interior spaces shall equal or exceed 1. 



SECTION 705 

COMBINED USE OF INSIDE AND OUTDOOR AIR 

(CONDITION 2) 

705.1 General. This section shall apply only to appliances lo- 
cated in unconfmed spaces in buildings of unusually tight con- 
struction. Combustion air supplied by a combined use of indoor 
and outdoor air shall be supplied through openings and ducts 
extending to the appliance room or to the vicinity of the 
appliance. 

705.1.1 Openings and supply ducts. Openings shall be pro- 
vided, located and sized in accordance with Sections 702.3. 1 
and 702.3.2; additionally, there shall be one opening to the 
outdoors having a free area of at least 1 square inch per 5,000 
Btu/h (440 mm^/kW) of total input of all appliances in the 
space. 



SECTION 706 
FORCED COMBUSTION AIR SUPPLY 

706.1 General. Where all combustion air and dilution air is 
provided by a mechanical forced-air system, the combustion 
air and dilution air shall be supplied at the minimum rate of 1 
cfm per 2,400 Btu/h [0.00067 mV(s . kW)] of combined input 
rating of all the fuel-burning appliances served. Each of the ap- 
pliances served shall be electrically interlocked to the mechani- 
cal forced-air system so as to prevent operation of the 
appliances when the mechanical system is not in operation. 
Where combustion air and dilution air is provided by the build- 
ing's mechanical ventilation system, the system shall provide 
the specified combustion/dilution air rate in addition to the re- 
quired ventilation air. 



SECTION 707 
DIRECT CONNECTION 

707.1 General. Fuel-burning appliances that are listed and la- 
beled for direct combustion air connection to the outdoors shall 
be installed in accordance with the manufacturer's installation 
instructions. 



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SECTION 708 
COMBUSTION AIR DUCTS 

708.1 General. Combustion air ducts shall: 

1. Be of galvanized steel complying with Chapter 6 or of 
equivalent corrosion-resistant material approved for this 
application. 

Exception: Within dwelhng units, unobstructed stud 
and joist spaces shall not be prohibited from convey- 
ing combustion air, provided that not more than one 
required fireblock is removed. 

2. Have a minimum cross-sectional dimension of 3 inches 
(76 mm). 

3. Terminate in an unobstructed space allowing free move- 
ment of combustion air to the appliances. 

4. Have the same cross-sectional areas as the free area of the 
openings to which they connect. 

5. Serve a single appliance enclosure. 

6. Not serve both upper and lower combustion air openings 
where both such openings are used. The separation be- 
tween ducts serving upper and lower combustion air 
openings shall be maintained to the source of combustion 
air. 

7. Not be screened where terminating in an attic space. 

8. Not slope downward toward the source of combustion 
air, where serving the upper required combustion air 
opening. 



SECTION 710 
OPENING LOCATION AND PROTECTION 

710.1 General. Combustion air openings to the outdoors shall 
comply with the location and protection provisions of Sections 
401.5 and 401.6 applicable to outside air intake openings. 



SECTION 709 
OPENING OBSTRUCTIONS 

709.1 General. The required size of openings for combustion 
and dilution air shall be based on the net free area of each open- 
ing. The net free area of an opening shall be that specified by the 
manufacturer of the opening covering. In the absence of such in- 
formation, openings covered with metal louvers shall be deemed 
to have a net free area of 75 percent of the area of the opening, 
and openings covered with wood louvers shall be deemed to 
have a net free area of 25 percent of the area of the opening. Lou- 
vers and grills shall be fixed in the open position. 

Exception: Louvers interlocked with the appliance so that 
they are proven to be 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 if 
the louvers fail to open during burner startup and to shut 
down the main burner if the louvers close during operation. 

709.2 Dampered openings. Where the combustion air openings 
are provided with volume, smoke or fire dampers, the dampers 
shall be electrically interlocked with the firing cycle of die appli- 
ances served, so as to prevent operation of any appliance that 
draws combustion and dilution air from the room when any of 
the dampers are closed. Manually operated dampers shall not be 
installed in combustion air openings. 



2003 INTERNATIONAL MECHANICAL CODE® 



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64 2003 INTERNATIONAL MECHANICAL CODE® 



CHAPTER 8 

CHIMNEYS AND VENTS 



SECTION 801 
GENERAL 

801.1 Scope. This chapter shall govern the installation, mainte- 
nance, repair and approval of factory-built chimneys, chimney 
liners, vents and connectors. This chapter shall also govern the 
utilization of masonry chimneys. Gas-fired appUances shall be 
vented in accordance with the International Fuel Gas Code. 

801.2 General. Every fuel-burning appliance shall discharge 
the products of combustion to a vent, factory-built chimney or 
masonry chimney, except for appliances vented in accordance 
with Section 804. The chimney or vent shall be designed for the 
type of appliance being vented. 

801.2.1 Oil-fired appliances. Oil-fired appliances shall be 
vented in accordance with this code and NFPA 31. 

801.3 Masonry chimneys. Masonry chimneys shall be con- 
structed in accordance with the International Building Code. 

801.4 Positive flow. Venting systems shall be designed and 
constructed so as to develop a positive flow adequate to convey 
all combustion products to the outside atmosphere. 

801.5 Design. Venting systems shall be designed in accordance 
with this chapter or shall be approved engineered systems. 

801.6 Minimum size of chimney or vent. Except as otherwise 
provided for in this chapter, the size of the chimney or vent, 
serving a single appliance, except engineered systems, shall 
have a minimum area equal to the area of the appHance connec- 
tion. 

801.7 Solid fuel appliance flues. The cross-sectional area of a 
flue serving a solid fuel-burning appliance shall be not greater 
than three times the cross-sectional area of the appliance flue 
collar or flue outlet. 

801.8 Abandoned inlet openings. Abandoned inlet openings 
in chimneys and vents shall be closed by an approved method. 

801.9 Positive pressure. Where an appliance equipped with a 
forced or induced draft system creates a positive pressure in the 
venting system, the venting system shall be designed and listed 
for positive pressure applications. 

801.10 Connection to fireplace. Connection of appUances to 
chimney flues serving fireplaces shall be in accordance with 
Sections 801.10.1 through 801.10.3. 

801.10.1 Closure and access. A noncombustible seal shall 
be provided below the point of connection to prevent entry 
of room air into the flue. Means shall be provided for access 
to the flue for inspection and cleaning. 

801.10.2 Connection to factory-built fireplace flue. An ap- 
pliance shall not be connected to a flue serving a factory -built 
fireplace unless the appHance is specifically listed for such in- 
stallation. The connection shall be made in accordance with 
the appUance manufacturer's installation instructions. 



801.10.3 Connection to masonry fireplace flue. A con- 
nector shall extend from the appliance to the flue serving a 
masonry fireplace such that the flue gases are exhausted di- 
rectly into the flue. The connector shall be provided with ac- 
cess or shall be removable for inspection and cleaning of 
both the connector and the flue. Listed direct connection de- 
vices shall be installed in accordance with their listing. 

801.11 Multiple solid fuel prohibited. A solid fuel-burning 
appliance or fireplace shall not connect to a chimney passage- 
way venting another appliance. 

801.12 Chimney entrance. Connectors shall connect to a 
chimney flue at a point not less than 12 inches (305 mm) above 
the lowest portion of the interior of the chimney flue. 

801.13 Cleanouts. Masonry chimney flues shall be provided 
with a cleanout opening having a minimum height of 6 inches 
(152 mm). The upper edge of the opening shall be located not 
less than 6 inches (152 mm) below the lowest chimney inlet 
opening. The cleanout shall be provided with a tight-fitting, 
noncombustible cover. 

Exception: Cleanouts shall not be required for chimney flues 
serving masonry fireplaces, if such flues are provided with 
access through the fireplace opening. 

801.14 Connections to exhauster. All appliance connections to 
a chimney or vent equipped with a power exhauster shall be 
made on the inlet side of the exhauster. All joints and piping on 
the positive pressure side of the exhauster shall be hsted for posi- 
tive pressure applications as specified by the manufacturer's in- 
stallation instructions for the exhauster. 

801.15 Fuel-fired appliances. Masonry chimneys utilized to 
vent fuel-fired appliances shall be located, constructed and sized 
as specified in the manufacturer's installation instructions for the 
appliances being vented. 

801.16 Flue lining. Masonry chimneys shall be lined. The lin- 
ing material shall be compatible with the type of appliance con- 
nected, in accordance with the appliance listing and 
manufacturer's installation instructions. Listed materials used 
as flue linings shall be installed in accordance with their list- 
ings and the manufacturer's installation instructions. 

801.16.1 Residential and low-heat appliances (general). 

Flue lining systems for use with residential-type and 
low-heat appliances shall be hmited to the following: 

1. Clay flue lining complying with the requirements of 
ASTM C 315 or equivalent. Clay flue lining shall be 
installed in accordance with the International Build- 
ing Code. 

2. Listed chinmey lining systems complying with UL 

1777. 

3. Other approved materials that will resist, without 
cracking, softening or corrosion, flue gases and con- 
densate at temperatures up to 1,800°F (982°C). 



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801.17 Space around lining. The space surrounding a flue lin- 
ing system or other vent installed within a masonry chimney 
shall not be used to vent any other appliance. This shall not pre- 
vent the installation of a separate flue lining in accordance with 
the manufacturer's installation instructions and this code. 

801.18 Existing chimneys and vents. Where an appliance is 
permanently disconnected from an existing chimney or vent, or 
where an appUance is connected to an existing chimney or vent 
during the process of a new installation, the chimney or vent 
shall comply with Sections 801.18.1 through 801.18.4. 

801.18.1 Size. The chimney or vent shall be resized as nec- 
essary to control flue gas condensation in the interior of the 
chimney or vent and to provide the appliance or appliances 
served with the required draft. For the venting of oil-fired 
appliances to masonry chimneys, the resizing shall be in ac- 
cordance with NFPA 3 1 . 

801.18.2 Flue passageways. The flue gas passageway shall 
be free of obstructions and combustible deposits and shall 
be cleaned if previously used for venting a sohd or liquid 
fuel-burning appHance or fireplace. The flue liner, chimney 
inner wall or vent inner wall shall be continuous and shall be 
free of cracks, gaps, perforations or other damage or deteri- 
oration which would allow the escape of combustion prod- 
ucts, including gases, moisture and creosote. Where an 
oil-fired appliance is connected to an existing masonry 
chimney, such chimney flue shall be repaired or relined in 
accordance with NFPA 31. 

801.18.3 Cleanout. Masonry chimneys shall be provided 
with a cleanout opening complying with Section 801.13. 

801.18.4 Clearances. Chimneys and vents shall have 
air-space clearance to combustibles in accordance with the 
International Building Code and the chimney or vent manu- 
facturer's installation instructions. 

Exception: Masonry chimneys equipped with a chim- 
ney lining system tested and listed for installation in 
chimneys in contact with combustibles in accordance 
with UL 1777, and installed in accordance with the man- 
ufacturer's instructions, shall not be required to have 
clearance between combustible materials and exterior 
surfaces of the masonry chimney. Noncombustible 
fireblocking shall be provided in accordance with the In- 
ternational Building Code. 

801.19 Multistory prohibited. Common venting systems for 
appliances located on more than one floor level shall be prohib- 
ited, except where all of the appliances served by the common 
vent are located in rooms or spaces that are accessed only from 
the outdoors. The appliance enclosures shall not communicate 
with the occupiable areas of the building. 

801.20 Plastic vent joints. Plastic pipe and fittings used to vent 
appliances shall be installed in accordance with the pipe manu- 
facturer's installafion instructions and the appliance manufac- 
turer's installation instructions. Solvent cement joints between 
ABS pipe and fittings shall be cleaned. Solvent cement joints 
between CPVC and PVC pipe and fittings shall be primed. The 
primer shall be a contrasfing color. 



Exception: Where compliance with this section would con- 
flict with the appUance manufacturer's installafion instruc- 
fions. 



SECTION 802 
VENTS 

802.1 General. All vent systems shall be listed and labeled. 
Type L vents and pellet vents shall be tested in accordance with 
UL641. 

802.2 Vent application. The applicadon of vents shall be in ac- 
cordance with Table 802.2. 

TABLE 802.2 
VENT APPLICATION 



VENT TYPES 


APPLIANCE TYPES 


Type L oil vents 


Oil-burning appliances listed and labeled 
for venting with Type L vents; gas 
appliances listed and labeled for 
venting with Type B vents. 


Pellet vents 


Pellet fuel-burning appliances listed and 
labeled for venting with pellet vents. 



802.3 Installation. Vent systems shall be sized, installed and 
terminated in accordance with the vent and appliance manufac- 
turer's installation instructions. 

802.4 Vent termination caps required. Type L vents shall ter- 
minate with a listed and labeled cap in accordance with the vent 
manufacturer's installation instructions. 

802.5 T^pe L vent terminations. Type L vents shall terminate 
not less than 2 feet (610 mm) above the highest point of the roof 
penetration and not less than 2 feet (610 mm) higher than any 
portion of a building within 10 feet (3048 mm). 

802.6 Minimum vent heights. Vents shall terminate not less 
than 5 feet (1524 mm) in vertical height above the highest con- 
nected appliance flue collar. 

Exceptions: 

1 . Venting systems of direct vent appliances shall be in- 
stalled in accordance with the appliance and the vent 
manufacturer's instructions. 

2. Appliances listed for outdoor installations incorporat- 
ing integral venting means shall be installed in accor- 
dance with their listings and the manufacturer's 
installation instructions. 

3. Pellet vents shall be installed in accordance with the 
appliance and the vent manufacturer's installation in- 
structions. 

802.7 Support of vents. All portions of vents shall be ade- 
quately supported for the design and weight of the materials 
employed. 

802.8 Insulation shield. Where vents pass through insulated 
assemblies, an insulation shield constructed of not less than 
No. 26 Gage sheet metal shall be installed to provide clearance 
between the vent and the insulation material. The clearance 
shall be not less than the clearance to combustibles specified by 
the vent manufacturer's installation instructions. Where vents 



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CHIMNEYS AND VENTS 



pass through attic space, the shield shall terminate not less than 
2 inches (5 1 mm) above the insulation materials and shall be se- 
cured in place to prevent displacement. Insulation shields pro- 
vided as part of a listed vent system shall be installed in 
accordance with the manufacturer's installation instructions. 



SECTION 803 
CONNECTORS 

803.1 Connectors required. Connectors shall be used to con- 
nect appliances to the vertical chimney or vent, except where 
the chimney or vent is attached directly to the appliance. 

803.2 Location. Connectors shall be located entirely within the 
room in which the connecting appliance is located, except as 
provided for in Section 803.10.4. Where passing through an 
unhealed space, a connector shall not be constructed of sin- 
gle-wall pipe. 

803.3 Size. The connector shall not be smaller than the size of 
the flue collar supplied by the manufacturer of the appliance. 
Where the appliance has more than one flue outlet, and in the 
absence of the manufacturer's specific instructions, the con- 
nector area shall be not less than the combined area of the flue 
outlets for which it acts as a conmion connector. 

803.4 Branch connections. All branch connections to the vent 
connector shall be made in accordance with the vent manufac- 
turer's instructions. 

803.5 Manual dampers. Manual dampers shall not be installed 
in connectors except in chimney connectors serving solid 
fuel-burning appliances. 

803.6 Automatic dampers. Automatic dampers shall be listed 
and labeled in accordance with UL 17 for oil-fired heating ap- 
pliances. The dampers shall be installed in accordance with the 
manufacturer's installation instructions. An automatic vent 
damper device shall not be installed on an existing appliance 
unless the appliance is listed and labeled and the device is in- 
stalled in accordance with the terms of its listing. The name of 
the installer and date of installation shall be marked on a label 
affixed to the damper device. 

803.7 Connectors serving two or more appliances. Where 
two or more connectors enter a common vent or chimney, the 
smaller connector shall enter at the highest level consistent 
with available headroom or clearance to combustible material. 

803.8 Vent connector construction. Vent connectors shall be 
constructed of metal. The minimum nominal thickness of the 
connector shall be 0.019 inch (0.5 mm) (No. 28 Gage) for gal- 
vanized steel, 0.022 inch (0.6 mm) (No. 26 B & S Gage) for 
copper, and 0.020 inch (0.5 mm) (No. 24 B & S Gage) for alu- 
minum. 

803.9 Chimney connector construction. Chimney connec- 
tors for low-heat appliances shall be of sheet steel pipe having 
resistance to corrosion and heat not less than that of galvanized 
steel specified in Table 803.9(1). Connectors for medium-heat 
appliances and high-heat appliances shall be of sheet steel not 
less than the thickness specified in Table 803.9(2). 



TABLE 803.9(1) 

MINIMUM CHIMNEY CONNECTOR THICKNESS FOR 

LOW-HEAT APPLIANCES 



DIAMETER OF CONNECTOR 
(inches) 


MINIMUM NOMINAL THICKNESS 
(galvanized) (inches) 


5 and smaller 


0.022 (No. 26 Gage) 


Larger than 5 and up to 10 


0.028 (No. 24 Gage) 


Larger than 10 and up to 16 


0.034 (No. 22 Gage) 


Larger than 16 


0.064 (No. 16 Gage) 



For SI: 1 inch = 25.4 mm. 



TABLE 803.9(2) 

MINIMUM CHIMNEY CONNECTOR THICKNESS FOR 

MEDIUM- AND HIGH-HEAT APPLIANCES 



AREA 
(square inches) 


EQUIVALENT ROUND 

DIAMETER 

(Inches) 


MINIMUM NOMINAL 

THICKNESS 

(inches) 


0-154 


0-14 


0.060 (No. 16 Gage) 


155-201 


15-16 


0.075 (No. 14 Gage) 


202-254 


17-18 


0.105 (No. 12 Gage) 


Greater than 254 


Greater than 18 


0.135 (No. 10 Gage) 



For SI: 1 inch = 25.4 mm, 1 square inch = 645.16 mm^. 

803.10 Installation. Connectors shall be installed in accordance 
with Sections 803.10.1 through 803.10.6. 

803.10.1 Supports and joints. Connectors shall be supported 
in an approved manner, and joints shall be fastened with sheet 
metal screws, rivets or other approved means. 

803.10.2 Length. The maximum horizontal length of a sin- 
gle-wall connector shall be 75 percent of the height of the 
chimney or vent. 

803.10.3 Connection. The connector shall extend to the in- 
ner face of the chimney or vent liner, but not beyond. A con- 
nector entering a masonry chimney shall be cemented to 
masonry in an approved manner. Where thimbles are in- 
stalled to facilitate removal of the connector from the ma- 
sonry chimney, the thimble shall be permanently cemented 
in place with high-temperature cement. 

803.10.4 Connector pass- through. Chimney connectors 
shall not pass through any floor or ceiling, nor through a 
fire-resistance-rated wall assembly. Chimney connectors 
for domestic-type appliances shall not pass through walls or 
partitions constructed of combustible material to reach a 
masonry chimney unless: 

1. The connector is labeled for wall pass-through and is 
installed in accordance with the manufacturer's in- 
structions; 

2. The connector is put through a device labeled for wall 
pass-through; or 

3. The connector has a diameter not larger than 10 
inches (254 nun) and is installed in accordance with 
one of the methods in Table 803.10.4. Concealed 
metal parts of the pass-through system in contact with 



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CHIMNEYS AND VENTS 



flue gases shall be of stainless steel or equivalent ma- 
terial that resists corrosion, softening or cracking up 
tol,800°F(980X). 

TABLE 803.10.4 

CHIMNEY CONNECTOR SYSTEMS AND CLEARANCES 

TO COMBUSTIBLE WALL MATERIALS FOR 

DOMESTIC HEATING APPUANCES^'^'*'''* 



ferent clearance, in which case the labeled clearance shall ap- 
ply. The clearance to combustibles for connectors shall be re- 
duced only in accordance with Section 308. 

TABLE 803.10.6 
CONNECTOR CLEARANCES TO COMBUSTIBLES 



System A 

(12-inch 

clearance) 


A 3.5-inch-thick brick wall shall be framed into the 
combustible wall. A 0.625-inch-thick fire-clay liner 
(ASTM C 315 or equivalent)' shall be firmly 
cemented in the center of the brick wall maintaining 
a 12-inch clearance to combustibles. The clay liner 
shall run from the outer surface of the bricks to the 
inner surface of the chimney liner. 


System B 

(9-inch 
clearance) 


A labeled solid-insulated factory-built chimney 
section (1-inch insulation) the same inside diameter 
as the connector shall be utilized. Sheet metal 
supports cut to maintain a 9-inch clearance to 
combustibles shall be fastened to the wall surface 
and to the chimney section. Fasteners shall not 
penetrate the chimney flue liner. The chimney length 
shall be flush with the masonry chimney liner and 
sealed to the masonry with water-insoluble refractory 
cement. Chimney manufacturers' parts shall be 
utilized to securely fasten the chimney connector to 
the chimney section. 


System C 

(6-inch 

clearance) 


A sheet metal (minimum number 24 Gage) 
ventilated thimble having two 1-inch air channels 
shall be installed with a sheet steel chimney 
connector (minimum number 24 Gage). Sheet steel 
supports (minimum number 24 Gage) shall be cut to 
maintain a 6-inch clearance between the thimble and 
combustibles. One side of the support shall be 
fastened to the wall on all sides. Glass-fiber 
insulation shall fill the 6-inch space between the 
thimble and the supports. 


System D 

(2-inch 

clearance) 


A labeled solid-insulated factory-built chimney 
section (1-inch insulation) with a diameter 2 inches 
larger than the chimney connector shall be installed 
with a sheet steel chimney connector (minimum 
number 24 Gage). Sheet metal supports shall be 
positioned to maintain a 2-inch clearance to 
combustibles and to hold the chimney connector to 
ensure that a 1-inch airspace surrounds the chimney 
connector through the chimney section. The steel 
support shall be fastened to the wall on all sides and 
the chimney section shall be fastened to the supports. 
Fasteners shall not penetrate the liner of the chimney 
section. 



For SI: 1 inch = 25.4 mm, 1.0 Btu x in/ft^ • h • °F = 0.144 W/m^ • K. 

a. Insulation material that is part of the wall pass-through system shall be 
noncombustible and shall have a thermal conductivity of 1 .0 Btu x inyft2 • h • 
°F or less. 

b. All clearances and thicknesses are minimums. 

c. Materials utilized to seal penetrations for the connector shall be 
noncombustible. 

d. Connectors for all systems except System B shall extend through the wall 
pass-through system to the inner face of the flue liner. 

e. ASTM C 315. 

803.10.5 Pitch. Connectors shall rise vertically to the chim- 
ney or vent with a minimum pitch equal to one-fourth unit 
vertical in 12 units horizontal (2-percent slope). 

803.10.6 Clearances. Connectors shall have a minimum 
clearance to combustibles in accordance with Table 803. 10.6. 
The clearances specified in Table 803.10.6 apply, except 
where the listing and labehng of an appliance specifies a dif- 



TYPE OF APPLIANCE 


MINIMUM CLEARANCE 
(inches) 


Domestic-type appliances 


Chimney and vent connectors 
Electric and oil incinerators 
Oil and solid fuel appliances 
Oil appliances labeled for venting 
with Type L vents 


18 
18 

9 


Commercial, industrial-type appliances 


Low-heat appliances 

Chimney connectors 

Oil and solid fuel boilers, furnaces 

and water heaters 
Oil unit heaters 
Other low-heat industrial appliances 


18 
18 
18 


Medium-heat appliances 

Chinmey connectors 

All oil and solid fuel appliances 


36 


High-heat appliances 

Masonry or metal connectors 
All oil and solid fuel appliances 


(As determined by the 
code official) 



For SI: 1 inch = 25.4 mm. 



SECTION 804 

DIRECT-VENT, INTEGRAL VENT AND 

MECHANICAL DRAFT SYSTEMS 

804.1 Direct-vent terminations. Vent terminals for di- 
rect-vent appliances shall be installed in accordance with the 
manufacturer's installation instructions 

804.2 Appliances with integral vents. Appliances incorporat- 
ing integral venting means shall be installed in accordance with 
their listings and the manufacturer's installation instructions. 

804.2.1 Terminal clearances. Appliances designed for nat- 
ural draft venting and incorporating integral venting means 
shall be located so that a minimum clearance of 9 inches 
(229 mm) is maintained between vent terminals and from 
any openings through which combustion products enter the 
building. Appliances using forced draft venting shall be lo- 
cated so that a minimum clearance of 12 inches (305 mm) is 
maintained between vent terminals and from any openings 
through which combustion products enter the building. 

804.3 Mechanical draft systems. Mechanical draft systems of 
either forced or induced draft design shall comply with Sec- 
tions 804.3.1 through 804.3.7. 

804.3.1 Forced draft systems. Forced draft systems and all 
portions of induced draft systems under positive pressure 
during operation shall be designed and installed so as to be 
gas tight to prevent leakage of combustion products into a 
building. 



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804.3.2 Automatic shutoff. Power exhausters serving auto- 
matically fired appliances shall be electrically connected to 
each appliance to prevent operation of the appliance when 
the power exhauster is not in operation. 

804.3.3 Termination. The termination of chimneys or vents 
equipped with power exhausters shall be located a minimum 
of 10 feet (3048 mm) from the lot line or from adjacent 
buildings. The exhaust shall be directed away from the 
building. 

804.3.4 Horizontal terminations. Horizontal terminations 
shall comply with the following requirements: 

1. Where located adjacent to walkways, the termination 
of mechanical draft systems shall be not less than 7 
feet (2134 mm) above the level of the walkway. 

2. Vents shall terminate at least 3 feet (914 mm) above 
any forced air inlet located within 10 feet (3048 mm). 

3. The vent system shall terminate at least 4 feet (1219 
mm) below, 4 feet (1219 mm) horizontally from or 1 
foot (305 mm) above any door, window or gravity air 
inlet into the building. 

4. The vent termination point shall not be located closer 
than 3 feet (914 mm) to an interior comer formed by 
two walls perpendicular to each other. 

5. The vent termination shall not be mounted directly 
above or within 3 feet (914 mm) horizontally from an 
oil tank vent or gas meter. 

6. The bottom of the vent termination shall be located at 
least 12 inches (305 mm) above finished grade. 

804.3.5 Vertical terminations. Vertical terminations shall 
comply with the following requirements: 

1. Where located adjacent to walkways, the termination 
of mechanical draft systems shall be not less than 7 
feet (2134 mm) above the level of the walkway. 

2. Vents shall terminate at least 3 feet (914 mm) above 
any forced air inlet located within 1 feet (3048 mm). 

3. Where the vent termination is located below an adja- 
cent roof structure, the termination point shall be lo- 
cated at least 3 feet (914 mm) from such structure. 

4. The vent shall terminate at least 4 feet (1219 mm) be- 
low, 4 feet (1219 mm) horizontally from, or 1 foot 
(305 mm) above any door, window or gravity air inlet 
for the building. 

5. A vent cap shall be installed to prevent rain from en- 
tering the vent system. 

6. The vent termination shall be located at least 3 feet 
(914 mm) horizontally from any portion of the roof 
structure. 

804.3.6 Exhauster connections. An appliance vented by 
natural draft shall not be connected into a vent, chimney or 
vent connector on the discharge side of a mechanical flue 
exhauster. 

804.3.7 Exhauster sizing. Mechanical flue exhausters and 
the vent system served shall be sized and installed in accor- 
dance with the manufacturer's installation instructions. 



804.3.8 Mechanical draft systems for manually fired ap- 
pliances and fireplaces. A mechanical draft system shall be 
permitted to be used with manually fired appliances and 
fireplaces where such system complies with all of the fol- 
lowing requirements: 

1. The mechanical draft device shall be Usted and in- 
stalled in accordance with the manufacturer's instal- 
lation instructions. 

2. A device shall be installed that produces visible and 
audible warning upon failure of the mechanical draft 
device or loss of electrical power, at any time that the 
mechanical draft device is turned on. This device shall 
be equipped with a battery backup if it receives power 
from the building wiring. 

3. A smoke detector shall be installed in the room with 
the appliance or fireplace. This device shall be 
equipped with a battery backup if it receives power 
from the building wiring. 



SECTION 805 
FACTORY-BUILT CHIMNEYS 

805.1 Listing. Factory-built chimneys shall be listed and la- 
beled and shall be installed and terminated in accordance with 
the manufacturer's installation instructions. 

805.2 Solid fuel appliances. Factory-built chimneys for use 
with solid fuel-burning appliances shall comply with the Type 
HT requirements of UL 103. 

Exception: Chimneys for use with fireplace stoves listed 
only to UL 737 shall comply with the requirements of UL 
103. 

805.3 Factory-built fireplaces. Chimneys for use with fac- 
tory-built fireplaces shall comply with the requirements of UL 
127. 

805.4 Support. Where factory-built chimneys are supported 
by structural members, such as joists and rafters, such members 
shall be designed to support the additional load. 

805.5 Medium-heat appliances. Factory-built chimneys for 
medium-heat appliances producing flue gases having a temper- 
ature above 1,000°F (538 °C), measured at the entrance to the 
chimney, shall comply with UL 959. 

805.6 Decorative shrouds. Decorative shrouds shall not be in- 
stalled at the termination of factory-built chimneys except 
where such shrouds are listed and labeled for use with the spe- 
cific factory-built chimney system and are installed in accor- 
dance with Section 304.1. 



SECTION 806 
METAL CHIMNEYS 

806.1 General. Metal chimneys shall be constructed and in- 
stalled in accordance with NFPA 211. 



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70 2003 INTERNATIONAL MECHANICAL CODE® 



• 



CHAPTER 9 

SPECIFIC APPLIANCES, FIREPLACES AND 
SOLID FUEL-BURNING EQUIPMENT 



SECTION 901 
GENERAL 

901.1 Scope, This chapter shall govern the approval, design, in- 
stallation, construction, maintenance, alteration and repair of 
the appliances and equipment specifically identified herein and 
factory-built fireplaces. The approval, design, installation, 
construction, maintenance, alteration and repair of gas-fired 
appliances shall be regulated by the International Fuel Gas 
Code. 

901.2 General. The requirements of this chapter shall apply to 
the mechanical equipment and appliances regulated by this 
chapter, in addition to the other requirements of this code. 

901.3 Hazardous locations. Fireplaces and solid fuel-burning 
appliances shall not be installed in hazardous locations. 

901.4 Fireplace accessories. Listed fireplace accessories shall 
be installed in accordance with the conditions of the listing and 
the manufacturer's installation instructions. 



SECTION 902 
MASONRY FIREPLACES 

902.1 General. Masonry fireplaces shall be constructed in ac- 
cordance with the International Building Code. 



SECTION 903 
FACTORY-BUILT FIREPLACES 

903.1 General. Factory-built fireplaces shall be listed and la- 
beled and shall be installed in accordance with the conditions of 
the listing. Factory-built fireplaces shall be tested in accor- 
dance with UL 127. 

903.2 Hearth extensions. Hearth extensions of approved fac- 
tory-built fireplaces and fireplace stoves shall be installed in ac- 
cordance with the listing of the fireplace. The hearth extension 
shall be readily distinguishable from the surrounding floor 
area. 

903.3 Unvented gas log heaters. An unvented gas log heater 
shall not be installed in a factory-built fireplace unless the 
fireplace system has been specifically tested, listed and labeled 
for such use in accordance with UL 127. 



SECTION 904 
PELLET FUEL-BURNING APPLIANCES 

904.1 General. Pellet fuel-burning appliances shall be listed 
and labeled and shall be installed in accordance with the terms 
of the listing. 



SECTION 905 
FIREPLACE STOVES AND ROOM HEATERS 

905.1 General. Fireplace stoves and solid-fuel-type room 
heaters shall be listed and labeled and shall be installed in ac- 
cordance with the conditions of the listing. Fireplace stoves 
shall be tested in accordance with UL 737. SoHd-fuel-type 
room heaters shall be tested in accordance with UL 1482. Fire- 
place inserts intended for installation in fireplaces shall be 
listed and labeled in accordance with the requirements of UL 
1482 and shall be installed in accordance with the manufac- 
turer's installation instructions. 

905.2 Connection to fireplace. The connection of solid fuel 
appliances to chimney flues serving fireplaces shall comply 
with Sections 801.7 and 801.10. 



SECTION 906 
FACTORY-BUILT BARBECUE APPLIANCES 

906.1 General. Factory-built barbecue appliances shall be of 
an approved type and shall be installed in accordance with the 
manufacturer's installation instructions, this chapter and 
Chapters 3, 5, 7, 8 and the International Fuel Gas Code. 



SECTION 907 
INCINERATORS AND CREMATORIES 

907.1 General. Incinerators and crematories shall be listed and 
labeled in accordance with UL 791 and shall be installed in ac- 
cordance with the manufacturer's installation instructions. 



SECTION 908 

COOLING TOWERS, EVAPORATIVE 

CONDENSERS AND FLUID COOLERS 

908.1 General. A cooling tower used in conjunction with an 
air-conditioning appliance shall be installed in accordance 
with the manufacturer's installation instructions. 

908.2 Access. Cooling towers, evaporative coAdensers and 
fluid coolers shall be provided with ready access. 

908.3 Location. Cooling towers, evaporative condensers and 
fluid coolers shall be located to prevent the discharge vapor 
plumes from entering occupied spaces. Plume discharges shall 
be not less than 5 feet (1524 mm) above or 20 feet (6096 mm) 
away from any ventilation inlet to a building. Location on the 
property shall be as required for buildings in accordance with 
the International Building Code. 

908.4 Support and anchorage. Supports for cooling towers, 
evaporative condensers and fluid coolers shall be designed in 
accordance with the International Building Code, Seismic re- 
straints shall be as required by the International Building Code. 



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908.5 Water supply. Water supplies and protection shall be as 
required by the International Plumbing Code. 

908.6 Drainage. Drains, overflows and blowdown provisions 
shall be indirectly connected to an approved disposal location. 
Discharge of chemical waste shall be approved by the appropri- 
ate regulatory authority. 

908.7 Refrigerants and hazardous fluids. Heat exchange equip- 
ment that contains a refrigerant and that is part of a closed refriger- 
ation system shall comply with Chapter 11. Heat exhange 
equipment containing heat transfer fluids which are flammable, 
combustible or hazardous shall comply with the International 
Fire Code, 



SECTION 909 
VENTED WALL FURNACES 

909.1 GeneraL Vented wall furnaces shall be installed in ac- 
cordance with their listing and the manufacturer's installation 
instructions. Oil-fired furnaces shall be tested in accordance 
with UL 730. 

909.2 Location. Vented wall furnaces shall be located so as not 
to cause a fire hazard to walls, floors, combustible furnishings 
or doors. Vented wall furnaces installed between bathrooms 
and adjoining rooms shall not circulate air from bathrooms to 
other parts of the building. 

909.3 Door swing. Vented wall furnaces shall be located so that 
a door cannot swing within 1 2 inches (305 mm) of an air inlet or 
air outlet of such furnace measured at right angles to the 
opening. Doorstops or door closers shall not be installed to ob- 
tain this clearance. 

909.4 Ducts prohibited. Ducts shall not be attached to wall 
furnaces. Casing extension boots shall not be installed unless 
listed as part of the appliance. 

909.5 Manual shutoff valve. A manual shutoff valve shall be 
installed ahead of all controls. 

909.6 Access. Vented wall furnaces shall be provided with ac- 
cess for cleaning of heating surfaces, removal of burners, re- 
placement of sections, motors, controls, filters and other 
working parts, and for adjustments and lubrication of parts re- 
quiring such attention. Panels, grilles and access doors that must 
be removed for normal servicing operations shall not be attached 
to the building construction. 



wall, and wall register models shall not be placed closer than 6 
inches (152 mm) to a comer. 

The furnace shall be placed such that a drapery or similar 
combustible object will not be nearer than 12 inches (305 mm) 
to any portion of the register of the furnace. Floor furnaces shall 
not be installed in concrete floor construction built on grade. 
The controlling thermostat for a floor furnace shall be located 
within the same room or space as the floor furnace or shall be 
located in an adjacent room or space that is permanently open 
to the room or space containing the floor furnace. 

910.3 Bracing. The floor around the furnace shall be braced 
and headed with a support framework design in accordance 
with the International Building Code. 

910.4 Clearance. The lowest portion of the floor furnace shall 
have not less than a 6-inch (152 mm) clearance from the grade 
level; except where the lower 6-inch (152 mm) portion of the 
floor furnace is sealed by the manufacturer to prevent entrance 
of water, the minimum clearance shall be reduced to not less 
than 2 inches (5 1 mm). Where these clearances are not present, 
the ground below and to the sides shall be excavated to form a 
pit under the furnace so that the required clearance is provided 
beneath the lowest portion of the furnace. A 12-inch (305 mm) 
minimum clearance shall be provided on all sides except the 
control side, which shall have an 18-inch (457 mm) minimum 
clearance. 



SECTION 911 
DUCT FURNACES 

911.1 General. Duct furnaces shall be installed in accordance 
with the manufacturer's installation instructions. Electric fur- 
naces shall be tested in accordance with UL 1995. 



SECTION 912 
INFRARED RADIANT HEATERS 

912.1 Support. Infrared radiant heaters shall be safely and ade- 
quately fixed in an approved position independent of fuel and 
electric supply lines. Hangers and brackets shall be 
noncombustible material. 

912.2 Clearances. Heaters shall be installed with clearances 
from combustible material in accordance with the manufac- 
turer's installation instructions. 



SECTION 910 
FLOOR FURNACES 

910.1 General. Floor furnaces shall be installed in accordance 
with their listing and the manufacturer's installation instruc- 
tions. Oil-fired furnaces shall be tested in accordance with UL 

729. 

910.2 Placement. Floor furnaces shall not be installed in the 
floor of any aisle or passageway of any auditorium, public hall, 
place of assembly, or in any egress element from any such room 
or space. 

With the exception of wall register models, a floor furnace 
shall not be placed closer than 6 inches (152 mm) to the nearest 



SECTION 913 
CLOTHES DRYERS 

913.1 General. Clothes dryers shall be installed in accordance 
with the manufacturer's installation instructions. Electric resi- 
dential clothes dryers shall be tested in accordance with an ap- 
proved test standard. Electric commercial clothes dryers shall 
be tested in accordance with UL 1240. Electric coin-operated 
clothes dryers shall be tested in accordance with UL 2158. 

913.2 Exhaust required. Clothes dryers shall be exhausted in 
accordance with Section 504. 

913.3 Clearances. Clothes dryers shall be installed with clear- 
ance to combustibles in accordance with the manufacturer's in- 
structions. 



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• 



SECTION 914 
SAUNA HEATERS 

914.1 Location and protection. Sauna heaters shall be located 
so as to minimize the possibility of accidental contact by a per- 
son in the room. 

914.1.1 Guards. Sauna heaters shall be protected from acci- 
dental contact by an approved guard or barrier of material 
having a low coefficient of thermal conductivity. The guard 
shall not substantially affect the transfer of heat from the 
heater to the room. 

914.2 Installation. Sauna heaters shall be listed and labeled 
and shall be installed in accordance with their listing and the 
manufacturer's installation instructions. 

914.3 Access. Panels, grilles and access doors that are required 
to be removed for normal servicing operations shall not be at- 
tached to the building. 

914.4 Heat and time controls. Sauna heaters shall be equipped 
with a thermostat that will limit room temperature to 194""? 
(90 °C). If the thermostat is not an integral part of the sauna 
heater, the heat-sensing element shall be located within 6 
inches (152 mm) of the ceiling. If the heat-sensing element is a 
capillary tube and bulb, the assembly shall be attached to the 
wall or other support, and shall be protected against physical 
damage. 

914.4.1 Timers. A timer, if provided to control main burner 
operation, shall have a maximum operating time of 1 hour. 
The control for the timer shall be located outside the sauna 
room. 

914.5 Sauna room. A ventilation opening into the sauna room 
shall be provided. The opening shall be not less than 4 inches by 
8 inches (102 mm by 203 mm) located near the top of the door 
into the sauna room. 

914.5.1 Warning notice. The following permanent notice, 
constructed of approved material, shall be mechanically at- 
tached to the sauna room on the outside: 

WARNING: DO NOT EXCEED 30 MINUTES IN 
SAUNA. EXCESSIVE EXPOSURE CAN BE HARMFUL 
TO HEALTH. ANY PERSON WITH POOR HEALTH 
SHOULD CONSULT A PHYSICIAN BEFORE USING 

SAUNA. 

The words shall contrast with the background and the 
wording shall be in letters not less than 0.25-inch (6.4 mm) 
high. 

Exception: This section shall not apply to one- and 
two-family dwelhngs. 



SECTION 915 

ENGINE AND GAS TURBINE-POWERED 

EQUIPMENT AND APPLIANCES 

915.1 General. The installation of liquid-fueled stationary in- 
ternal combustion engines and gas turbines, including fuel stor- 
age and piping, shall meet the requirements of NFPA 37. 

915.2 Powered equipment and appliances. Permanently in- 
stalled equipment and appliances powered by internal combus- 



tion engines and turbines shall be installed in accordance with 
the manufacturer's installation instructions and NFPA 37. 



SECTION 916 
POOL AND SPA HEATERS 

916.1 General. Pool and spa heaters shall be installed in accor- 
dance with the manufacturer's installation instructions. 
Oil-fired pool and spa heaters shall be tested in accordance 
with UL 726. Electric pool and spa heaters shall be tested in ac- 
cordance with UL 1261. 



SECTION 917 
COOKING APPLIANCES 

917.1 Cooking appliances. Cooking appliances that are de- 
signed for permanent installation, including ranges, ovens, 
stoves, broilers, grills, fryers, griddles and barbecues, shall be 
listed, labeled and installed in accordance with the manufac- 
turer's installation instructions. Oil-burning stoves shall be 
tested in accordance with UL 896. Solid fuel-fired ovens shall 
be tested in accordance with UL 2162. 

917.2 Prohibited location. Cooking appliances designed, 
tested, listed and labeled for use in commercial occupancies 
shall not be installed within dwelling units or within any area 
where domestic cooking operations occur. 

917.3 Domestic appliances. Cooking appliances installed 
within dwelling units and within areas where domestic cooking 
operations occur shall be listed and labeled as household-type 
appliances for domestic use 



SECTION 918 
FORCED-AIR WARM-AIR FURNACES 

918.1 Forced-air furnaces. Oil-fired furnaces shall be tested 
in accordance with UL 727. Electric furnaces shall be tested in 
accordance with UL 1995. Solid fuel furnaces shall be tested in 
accordance with UL 39 1 . Forced-air furnaces shall be installed 
in accordance with the listings and the manufacturer's installa- 
tion instructions. 

918.2 Minimum duct sizes. The minimum unobstructed total 
area of the outside and return air ducts or openings to a 
forced-air warm-air furnace shall be not less than 2 square 
inches per 1,000 Btu/h (4402 mm^/kW) output rating capacity 
of the furnace and not less than that specified in the furnace 
manufacturer's installation instructions. The minimum unob- 
structed total area of supply ducts from a forced-air warm-air 
furnace shall not be less than 2 square inches for each 1,000 
Btu/h (4402 mm^/kW) output rating capacity of the furnace and 
not less than that specified in the furnace manufacturer's instal- 
lation instructions. 

Exception: The total area of the supply air ducts and outside 
and return air ducts shall not be required to be larger than the 
minimum size required by the furnace manufacturer's in- 
stallation instructions. 

918.3 Heat pumps. The minimum unobstructed total area of 
the outside and return air ducts or openings to a heat pump shall 
be not less than 6 square inches per 1,000 Btu/ii (13 208 



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mm^/kW) output rating or as indicated by the conditions of 
listing of the heat pump. Electric heat pumps shall be tested in 
accordance with UL 1995. 

918.4 Dampers. Volume dampers shall not be placed in the air 
inlet to a furnace in a manner that will reduce the required air to 
the furnace. 

918.5 Circulating air ducts for forced-air warm-air fur- 
naces. Circulating air for fuel-burning, forced-air-type, 
warm-air furnaces shall be conducted into the blower housing 
from outside the furnace enclosure by continuous air-tight 
ducts. 

918.6 Proliibited sources. Outside or return air for a forced-air 
heating system shall not be taken from the following locations: 

1 . Closer than 1 feet (3048 mm) from an appliance vent 
outlet, a vent opening from a plumbing drainage sys- 
tem or the discharge outlet of an exhaust fan, unless 
the outlet is 3 feet (914 mm) above the outside air in- 
let. 

2. Where there is the presence of objectionable odors, 
fumes or flammable vapors; or where located less 
than 10 feet (3048 mm) above the surface of any abut- 
ting public way or driveway; or where located at grade 
level by a sidewalk, street, alley or driveway. 

3. A hazardous or insanitary location or a refrigeration 
machinery room as defined in this code. 

4. A room or space, the volume of which is less than 25 
percent of the entire volume served by such system. 
Where connected by a permanent opening having an 
area sized in accordance with Sections 918.2 and 
918.3, adjoining rooms or spaces shall be considered 
as a single room or space for the purpose of determin- 
ing the volume of such rooms or spaces. 

Exception: The minimum volume requirement 
shall not apply where the amount of return air 
taken from a room or space is less than or equal to 
the amount of supply air delivered to such room or 
space. 

5. A closet, bathroom, toilet room, kitchen, garage, me- 
chanical room, boiler room or furnace room. 

6. A room or space containing a fuel-burning appliance 
where such room or space serves as the sole source of 
return air. 

Exceptions: 

1. This shall not apply where the fuel-burning 
appliance is a direct- vent appliance. 

2. This shall not apply where the room or space 
complies with the following requirements: 

2.1. The return air shall be taken from a 
room or space having a volume ex- 
ceeding 1 cubic foot for each 10 
Btu/h (9.6 LAV) of combined input 
rating of all fuel-burning appliances 
therein. 

2.2. The volume of supply air discharged 
back into the same space shall be ap- 



proximately equal to the volume of 
return air taken from the space. 

2.3. Return-air inlets shall not be located 
within 10 feet (3048 mm) of any ap- 
pliance firebox or draft hood in the 
same room or space. 

3. This shall not apply to rooms or spaces con- 
taining solid fuel-burning appliances, pro- 
vided that return-air inlets are located not 
less than 10 feet (3048 mm) from the firebox 
of such appliances. 

918.7 Outside opening protection. Outdoor air intake open- 
ings shall be protected in accordance with Section 401.6. 

918.8 Return-air limitation. Return air from one dwelling 
unit shall not be discharged into another dwelling unit. 



SECTION 919 
CONVERSION BURNERS 

919.1 Conversion burners. The installation of conversion burn- 
ers shall conform to ANSI Z21.8. 



SECTION 920 
UNIT HEATERS 

920.1 General. Unit heaters shall be installed in accordance 
with the listing and the manufacturer's installation instructions. 
Oil-fired unit heaters shall be tested in accordance with UL 

731. 

920.2 Support. Suspended-type unit heaters shall be supported 
by elements that are designed and constructed to accommodate 
the weight and dynamic loads. Hangers and brackets shall be of 
noncombustible material. Suspended-type oil-fired unit heat- 
ers shall be installed in accordance with NFPA 31. 

920.3 Ductwork. A unit heater shall not be attached to a 
warm-air duct system unless listed for such installation. 



SECTION 921 
VENTED ROOM HEATERS 

921.1 General. Vented room heaters shall be listed and labeled 
and shall be installed in accordance with the conditions of the 
listing and the manufacturer's instructions. 



SECTION 922 
KEROSENE AND OIL-FIRED STOVES 

922.1 General. Kerosene and oil-fired stoves shall be Hsted 
and labeled and shall be installed in accordance with the condi- 
tions of the listing and the manufacturer's installation 
instructions. Kerosene and oil-fired stoves shall comply with 
NFPA 31. Oil-fired stoves shall be tested in accordance with 
UL 896. 



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SECTION 923 
SMALL CERAMIC KILNS 

923.1 GeneraL The provisions of this section shall apply to 
kilns that are used for ceramics, have a maximum interior vol- 
ume of 20 cubic feet (0.566 m^) and are used for hobby and 
noncommercial purposes. 

923.1,1 Installation. Kilns shall be installed in accordance 
with the manufacturer's installation instructions and the 
provisions of this code. 

SECTION 924 
STATIONARY FUEL CELL POWER PLANTS 

924.1 General. Stationary fuel cell power plants having a power 
output not exceeding 1,000 kW, shall be tested in accordance 
with ANSI Z21.83 and shall be installed in accordance with the 
manufacturer's installation instructions and NFPA 853. 



SECTION 925 
MASONRY HEATERS 

925.1 General. Masonry heaters shall be constructed in accor- 
dance with the International Building Code. 



• 



2003 INTERNATIONAL MECHANICAL CODE® 75 



76 2003 INTERNATIONAL MECHANICAL CODE® 



CHAPTER 10 

BOILERS, WATER HEATERS AND 
PRESSURE VESSELS 



• 



SECTION 1001 
GENERAL 

1001.1 Scope. This chapter shall govern the installation, alter- 
ation and repair of boilers, water heaters and pressure vessels. 

Exceptions: 

1. Pressure vessels used for unheated water supply. 

2. Portable unfired pressure vessels and Interstate Com- 
merce Commission containers. 

3. Containers for bulk oxygen and medical gas. 

4. Unfired pressure vessels having a volume of 5 cubic 
feet (0.14 m^) or less operating at pressures not ex- 
ceeding 250 pounds per square inch (psi) (1724 kPa) 
and located within occupancies of Groups B, F, H, M, 
R, S and U. 

5. Pressure vessels used in refrigeration systems that are 
regulated by Chapter 1 1 of this code. 

6. Pressure tanks used in conjunction with coaxial ca- 
bles, telephone cables, power cables and other similar 
humidity control systems. 

7. Any boiler or pressure vessel subject to inspection by 
federal or state inspectors. 



space heating at temperatures higher than 140°F (60°C), a 
tempering valve shall be provided to temper the water sup- 
plied to the potable hot water distribution system to a tem- 
perature of 140°F (60°C) or less. 

1002.3 Supplemental water-heating devices. Potable wa- 
ter-heating devices that utilize refrigerant-to-water heat 
exchangers shall be approved and installed in accordance with 
the International Plumbing Code and the manufacturer's 
installation instructions. 



SECTION 1003 
PRESSURE VESSELS 

1003.1 General. All pressure vessels shall bear the label of an 
approved agency and shall be installed in accordance with the 
manufacturer's installation instructions. 

1003.2 Piping. All piping materials, fittings, joints, connec- 
tions and devices associated with systems utilized in conjunc- 
tion with pressure vessels shall be designed for the specific 
application and shall be approved. 

1003.3 Welding. Welding on pressure vessels shall be per- 
formed by approved welders in compliance with nationally rec- 
ognized standards. 



SECTION 1002 
WATER HEATERS 

1002.1 General. Potable water heaters and hot water storage 
tanks shall be listed and labeled and installed in accordance 
with the manufacturer's installation instructions, the Interna- 
tional Plumbing Code and this code. All water heaters shall be 
capable of being removed without first removing a permanent 
portion of the building structure. The potable water connec- 
tions and relief valves for all water heaters shall conform to the 
requirements of the International Plumbing Code. Domestic 
electric water heaters shall comply with UL 174 or UL 1453. 
Commercial electric water heaters shall comply with UL 1453. 
Oil-fired water heaters shall comply with UL 732. 

1002.2 Water heaters utilized for space heating. Water heat- 
ers utilized both to supply potable hot water and provide hot 
water for space-heating applications shall be listed and labeled 
for such applications by the manufacturer and shall be installed 
in accordance with the manufacturer's installation instructions 
and the International Plumbing Code. 

1002.2.1 Sizing. Water heaters utilized for both potable wa- 
ter heating and space-heating applications shall be sized to 
prevent the space-heating load from diminishing the re- 
quired potable water-heating capacity. 

1002.2.2 Scald protection. Where a combination potable 
water-heating and space-heating system requires water for 



SECTION 1004 
BOILERS 

1004.1 Standards. Oil-fired boilers and their control systems 
shall be listed and labeled in accordance with UL 726. Electric 
boilers and their control systems shall be listed and labeled in 
accordance with UL 834. Boilers shall be designed and con- 
structed in accordance with the requirements of ASME CSD- 1 
and as applicable, the ASME Boiler and Pressure Vessel Code, 
Sections I, II, V, and IX; NFPA 8501; NFPA 8502 or NFPA 
8504. 

1004.2 Installation. In addition to the requirements of this 
code, the installation of boilers shall conform to the manufac- 
turer's instructions. Operating instructions of a permanent type 
shall be attached to the boiler. Boilers shall have all controls set, 
adjusted and tested by the installer. The manufacturer's rating 
data and the nameplate shall be attached to the boiler. 

1004.3 Working clearance. Clearances shall be maintained 
around boilers, generators, heaters, tanks and related equip- 
ment and appliances so as to permit inspection, servicing, 
repau-, replacement and visibility of all gauges. When boilers 
are installed or replaced, clearance shall be provided to allow 
access for inspection, maintenance and repair. Passageways 
around all sides of boilers shall have an unobstructed width of 
not less than 1 8 inches (457 nun), unless otherwise approved. 



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1004.3.1 Top clearance. High-pressure steam boilers hav- 
ing a steam-generating capacity in excess of 5,000 pounds 
per hour (2268 kg/h) or having a heating surface in excess of 
1,000 square feet (93 m^) or input in excess of 5,000,000 
Btu/h (1465 kW) shall have a minimum clearance of 7 feet 
(2134 mm) from the top of the boiler to the ceiling. 
Steam-heating boilers and hot-water-heating boilers that 
exceed one of the following limits: 5,000,000 Btu/h input 
(1465 kW); 5,000 pounds of steam per hour (2268 kg/h) ca- 
pacity or a 1,000-square-foot (93 m^) heating surface; and 
high-pressure steam boilers that do not exceed one of the 
following limits: 5,000,000 Btu/h input (1465 kW); 5,000 
pounds of steam per hour (2268 kg/h) capacity or a 
1,000-square-foot (93 m^) heating surface; and all boilers 
with manholes on top of the boiler, shall have a minimum 
clearance of 3 feet (914 mm) from the top of the boiler to the 
ceiling. Package boilers, steam-heating boilers and hot- wa- 
ter-heating boilers without manholes on top of the shell and 
not exceeding one of the limits of this section shall have a 
minimum clearance of 2 feet (610 mm) from the ceiling. 

1004.4 Mounting. Equipment shall be set or mounted on a 
level base capable of supporting and distributing the weight 
contained thereon. Boilers, tanks and equipment shall be se- 
cured in accordance with the manufacturer's installation in- 
structions. 

1004.5 Floors. Boilers shall be mounted on floors of 
noncombustible construction, unless listed for mounting on 
combustible flooring. 

1004.6 Boiler rooms and enclosures. Boiler rooms and enclo- 
sures and access thereto shall comply with the International 
Building Code and Chapter 3 of this code. Boiler rooms shall be 
equipped with a floor drain or other approved means for dispos- 
ing of hquid waste. 

1004.7 Operating adjustments and instructions. Hot water 
and steam boilers shall have all operating and safety controls 
set and operationally tested by the installing contractor. A com- 
plete control diagram and boiler operating instructions shall be 
furnished by the installer for each installation. 



SECTION 1005 
BOILER CONNECTIONS 

1005.1 Valves. Every boiler or modular boiler shall have a shut- 
off valve in the supply and return piping. For multiple boiler or 
multiple modular boiler installations, each boiler or modular 
boiler shall have individual shutoff valves in the supply and re- 
turn piping. 

Exception: Shutoff valves are not required in a system hav- 
ing a single low-pressure steam boiler. 

1005.2 Potable water supply. The water supply to all boilers 
shall be connected in accordance with the International 
Plumbing Code. 



SECTION 1006 

SAFETY AND PRESSURE RELIEF 

VALVES AND CONTROLS 

1006.1 Safety valves for steam boilers. All steam boilers shall 
be protected with a safety valve. 

1006.2 Safety relief valves for hot water boilers. Hot water 
boilers shall be protected with a safety relief valve. 

1006.3 Pressure relief for pressure vessels. All pressure ves- 
sels shall be protected with a pressure relief valve or pres- 
sure-limiting device as required by the manufacturer's 
installation instructions for the pressure vessel. 

1006.4 Approval of safety and safety relief valves. Safety and 
safety relief valves shall be listed and labeled, and shall have a 
minimum rated capacity for the equipment or appliances 
served. Safety and safety reUef valves shall be set at a maxi- 
mum of the nameplate pressure rating of the boiler or pressure 
vessel. 

1006.5 Installation. Safety or relief valves shall be installed di- 
rectly into the safety or relief valve opening on the boiler or 
pressure vessel. Valves shall not be located on either side of a 
safety or relief valve connection. The relief valve shall dis- 
charge by gravity. 

1006.6 Safety and relief valve discharge. Safety and relief 
valve discharge pipes shall be of rigid pipe that is approved for 
the temperature of the system. The discharge pipe shall be the 
same diameter as the safety or relief valve outlet. Safety and re- 
lief valves shall not discharge so as to be a hazard, a potential 
cause of damage or otherwise a nuisance. High-pressure-steam 
safety valves shall be vented to the outside of the structure. 
Where a low-pressure safety valve or a relief valve discharges 
to the drainage system, the installation shall conform to the In- 
ternational Plumbing Code. 

1006.7 Boiler safety devices. Boilers shall be equipped with 
controls and limit devices as required by the manufacturer's in- 
stallation instructions and the conditions of the listing. 

1006.8 Electrical requirements. The power supply to the elec- 
trical control system shall be from a two-wire branch circuit that 
has a grounded conductor, or from an isolation transformer with 
a two-wire secondary. Where an isolation transformer is pro- 
vided, one conductor of the secondary winding shall be 
grounded. Control voltage shall not exceed 150 volts nominal, 
Une to line. Control and limit devices shall interrupt the un- 
grounded side of the circuit. A means of manually disconnecting 
the control circuit shall be provided and controls shall be ar- 
ranged so that when deenergized, the burner shall be inoperative. 
Such disconnecting means shall be capable of being locked in 
the off position and shall be provided with ready access. 



SECTION 1007 
BOILER LOW-WATER CUTOFF 

1007.1 General. All steam and hot water boilers shall be pro- 
tected with a low-water cutoff control. 

1007.2 Operation. The low-water cutoff shall automatically 
stop the combustion operation of the appliance when the water 
level drops below the lowest safe water level as established by 
the manufacturer. 



78 



2003 INTERNATIONAL MECHANICAL CODE® 



BOILERS, WATER HEATERS AND PRESSURE VESSELS 



« 



• 



SECTION 1008 
STEAM BLOWOFF VALVE 

1008.1 General. Every steam boiler shall be equipped with a 
quick-opening blowoff valve. The valve shall be installed in the 
opening provided on the boiler. The minimum size of the valve 
shall be the size specified by the boiler manufacturer or the size 
of the boiler blowoff- valve opening. 

1008.2 Discharge. Blowoff valves shall discharge to a safe 
place of disposal. Where discharging to the drainage system, 
the installation shall conform to the International Plumbing 
Code. 



SECTION 1009 
HOT WATER BOILER EXPANSION TANK 

1009.1 Where required. An expansion tank shall be installed 
in every hot water system. For multiple boiler installations, a 
minimum of one expansion tank is required. Expansion tanks 
shall be of the closed or open type. Tanks shall be rated for the 
pressure of the hot water system. 

1009.2 Closed-type expansion tanks. Closed-type expansion 
tanks shall be installed in accordance with the manufacturer's 
instructions. The size of the tank shall be based on the capacity 
of the hot-water-heating system. The minimum size of the tank 
shall be determined in accordance with the following equation: 



V.= 



(0.0004ir- 0.0466) y. 






(Equation 10-1) 



For SI: 



SECTION 1010 
GAUGES 

1010.1 Hot water boiler gauges. Every hot water boiler shall 
have a pressure gauge and a temperature gauge, or a combina- 
tion pressure and temperature gauge. The gauges shall indicate 
the temperature and pressure within the normal range of the 
system's operation. 

1010.2 Steam boiler gauges. Every steam boiler shall have a 
water-gauge glass and a pressure gauge. The pressure gauge 
shall indicate the pressure within the normal range of the 
system's operation. 

1010.2.1 Water-gauge glass. The gauge glass shall be in- 
stalled so that the midpoint is at the normal boiler water 
level. 



SECTION 1011 
TESTS 

1011.1 Tests. Upon completion of the assembly and installa- 
tion of boilers and pressure vessels, acceptance tests shall be 
conducted in accordance with the requirements of the ASME 
Boiler and Pressure Vessel Code. Where field assembly of 
pressure vessels or boilers is required, a copy of the completed 
U- 1 Manufacturer's Data Report required by the ASME Boiler 
and Pressure Vessel Code shall be submitted to the code offi- 
cial. 

1011.2 Test gauges. An indicating test gauge shall be con- 
nected directly to the boiler or pressure vessel where it is visible 
to the operator throughout the duration of the test. The pressure 
gauge scale shall be graduated over a range of not less than one 
and one-half times and not greater than four times the maxi- 
mum test pressure. All gauges utilized for testing shall be cali- 
brated and certified by the test operator. 



_ (Q.Q QQ738r- 0.03348) K 






where: 

V^ = Minimum volume of tanks (gallons) (L). 

V, = Volume of system, not including expansion tanks 
(gallons) (L). 

T = Average operating temperature (°F) (°C). 

P^ = Atmospheric pressure (psi) (kPa). 

Pf = Fill pressure (psi) (kPa). 

P^ = Maximum operating pressure (psi) (kPa). 

1009.3 Open-type expansion tanks. Open-type expansion 
tanks shall be located a minimum of 4 feet (1219 mm) above the 
highest heating element. The tank shall be adequately sized for 
the hot water system. An overflow with a minimum diameter of 1 
inch (25 mm) shall be installed at the top of the tank. The over- 
flow shall discharge to the drainage system in accordance with 
the International Plumbing Code. 



2003 INTERNATIONAL MECHANICAL CODE® 



79 



80 2003 INTERNATIONAL MECHANICAL CODE® 



CHAPTER 11 

REFRIGERATION 



SECTION 1101 
GENERAL 

1101.1 Scope. This chapter shall govern the design, installation, 
construction and repair of refrigeration systems that vaporize 
and Uquefy a fluid during the refrigerating cycle. Refrigerant 
piping design and installation, including pressure vessels and 
pressure rehef devices, shall conform to this code. Permanently 
installed refrigerant storage systems and other components shall 
be considered as part of the refrigeration system to which they 
are attached. 

1101.2 Factory-built equipment and appliances. Listed and 
labeled self-contained, factory-built equipment and appliances 
shall be tested in accordance with UL 207, 412, 471 or 1995. 
Such equipment and appliances are deemed to meet the design, 
manufacture and factory test requirements of this code if in- 
stalled in accordance with their listing and the manufacturer's 
installation instructions. 

1101.3 Protection. Any portion of a refrigeration system that is 
subject to physical damage shall be protected in an approved 
manner. 

1101.4 Water connection. Water supply and discharge con- 
nections associated with refrigeration systems shall be made in 
accordance with this code and the International Plumbing 
Code. 

1101.5 Fuel gas connection. Fuel gas devices, equipment and 
appliances used with refrigeration systems shall be installed in 
accordance with the International Fuel Gas Code. 

1101.6 General. Refrigeration systems shall comply with the re- 
quirements of this code and, except as modified by this code, 
ASHRAE 15. Anmionia-refrigerating systems shall comply 
with this code and, except as modified by this code, ASHRAE 15 
and EAR 2. 

1101.7 Maintenance. Mechanical refrigeration systems shall 
be maintained in proper operating condition, free from accu- 
mulations of oil, dirt, waste, excessive corrosion, other debris 
and leaks. 

1101.8 Change in refrigerant type. The type of refrigerant in 
refrigeration systems having a refrigerant circuit containing 
more than 220 pounds of Group A 1 or 30 pounds of any other 
group refrigerant shall not be changed without prior notifica- 
tion to the code official and compliance with the applicable 
code provisions for the new refrigerant type. 

[F] 1101.9 Refrigerant discharge. Notification of refrigerant 
discharge shall be provided in accordance with the Interna- 
tional Fire Code. 



SECTION 1102 
SYSTEM REQUIREMENTS 

1102.1 General. The system classification, allowable refriger- 
ants, maximum quantity, enclosure requirements, location lim- 
itations, and field pressure test requirements shall be 
determined as follows: 

1. Determine the refrigeration system's classification, in 
accordance with Section 1103.3. 

2. Determine the refrigerant classification in accordance 
with Section 1103.1. 

3. Determine the maximum allowable quantity of refriger- 
ant in accordance with Section 1 104, based on type of re- 
frigerant, system classification, and occupancy. 

4. Determine the system enclosure requirements in accor- 
dance with Section 1104. 

5. Refrigeration equipment and appliance location and in- 
stallation shall be subject to the limitations of Chapter 3. 

6. Nonfactory-tested, field-erected equipment and appli- 
ances shall be pressure tested in accordance with Section 
1108. 

1102.2 Refrigerants. The refrigerant shall be that which the 
equipment or apphance was designed to utilize or converted to 
utilize. Refrigerants not identified in Table 1103.1 shall be ap- 
proved before use. 

1102.2.1 Mixing. Refrigerants, including refrigerant 
blends, with different designations in ASHRAE 34 shall not 
be mixed in a system. 

Exception: Addition of a second refrigerant is allowed 
where permitted by the equipment or apphance manu- 
facturer to improve oil return at low temperatures. The 
refrigerant and amount added shall be in accordance with 
the manufacturer's instructions. 

1102.2.2 Purity. Refrigerants used in refrigeration systems 
shall be new, recovered or reclaimed refrigerants in accor- 
dance with Section 1102.2,2.1, 1102.2.2.2 or 1102.2.2.3. 
Where required by the equipment or appliance owner or the 
code official, the installer shall furnish a signed declaration 
that the refrigerant used meets the requirements of Section 
1102.2.2.1, 1102.2.2.2 or 1102.2.2.3. 

Exception: The refrigerant used shall meet the purity 
specifications set by the manufacturer of the equipment 
or appliance in which such refrigerant is used where such 
specifications are different from that specified in Sec- 
tions 1102.2.2.1, 1102.2.2.2 and 1102.2.2.3. 

1102.2.2.1 New refrigerants. Refrigerants shall be of a 
purity level specified by the equipment or appliance 
manufacturer. 



2003 INTERNATIONAL MECHANICAL CODE® 



81 



REFRIGERATION 



1102.2.2.2 Recovered refrigerants. Refrigerants that 
are recovered from refrigeration and air-conditioning 
systems shall not be reused in other than the system 
from which they were recovered and in other systems of 
the same owner. Recovered refrigerants shall be filtered 
and dried before reuse. Recovered refrigerants that 
show clear signs of contamination shall not be reused 
unless reclaimed in accordance with Section 
1102.2.2.3. 

1102.2.2.3 Reclaimed refrigerants. Used refrigerants 
shall not be reused in a different owner's equipment or 
appliances unless tested and found to meet the purity re- 
quirements of ARI 700. Contaminated refrigerants 
shall not be used unless reclaimed and found to meet the 
purity requirements of ARI 700. 



SECTION 1103 
REFRIGERATION SYSTEM CLASSIFICATION 

1103.1 Refrigerant classification. Refrigerants shall be 
classified in accordance with ASHRAE 34 as listed in Table 
1103.1. 

1103.2 Occupancy ciassincation. Locations of refrigerating 
systems are described by occupancy classifications that con- 
sider the ability of people to respond to potential exposure to 
refrigerants. Where equipment or appliances, other than pip- 
ing, are located outside a building and within 20 feet (6096 
mm) of any building opening, such equipment or appliances 
shall be governed by the occupancy classification of the build- 
ing. Occupancy classifications shall be defined as follows: 

1 . Institutional occupancy is that portion of premises from 
which, because they are disabled, debilitated or con- 
fined, occupants cannot readily leave without the assis- 
tance of others. Institutional occupancies include, 
among others, hospitals, nursing homes, asylums and 
spaces containing locked cells. 

2. Public assembly occupancy is that portion of premises 
where large numbers of people congregate and from 
which occupants cannot quickly vacate the space. Pub- 
lic assembly occupancies include, among others, audi- 
toriums, ballrooms, classrooms, passenger depots, 
restaurants and theaters. 

3. Residential occupancy is that portion of premises that 
provides the occupants with complete independent liv- 
ing facilities, including permanent provisions for liv- 
ing, sleeping, eating, cooking and sanitation. 
Residential occupancies include, among others, dormi- 
tories, hotels, multiunit apartments and private resi- 
dences. 

4. Commercial occupancy is that portion of premises 
where people transact business, receive personal ser- 
vice or purchase food and other goods. Commercial oc- 



cupancies include, among others, office and profes- 
sional buildings, markets (but not large mercantile 
occupancies) and work or storage areas that do not qual- 
ify as industrial occupancies. 

5. Large mercantile occupancy is that portion of premises 
where more than 100 persons congregate on levels 
above or below street level to purchase personal mer- 
chandise. 

6. Industrial occupancy is that portion of premises that is 
not open to the public, where access by authorized per- 
sons is controlled, and that is used to manufacture, pro- 
cess or store goods such as chemicals, food, ice, meat or 
petroleum. 

7. Mixed occupancy occurs when two or more occupan- 
cies are located within the same building. When each 
occupancy is isolated from the rest of the building by 
tight walls, floors and ceilings and by self-closing 
doors, the requirements for each occupancy shall apply 
to its portion of the building. When the various occu- 
pancies are not so isolated, the occupancy having the 
most stringent requirements shall be the governing oc- 
cupancy. 

1103.3 System classification. Refrigeration systems shall be 
classified according to the degree of probability that refriger- 
ant leaked from a failed connection, seal, or component could 
enter an occupied area. The distinction is based on the basic 
design or location of the components. 

1103.3.1 Low-probability systems. Double-indirect 
open-spray systems, indirect closed systems and indirect- 
vented closed systems shall be classified as low-probabil- 
ity systems, provided that all refrigerant-containing piping 
and fittings are isolated when the quantities in Table 
1103.1 are exceeded. 

1103.3.2 High-probability systems. Direct systems and 
indirect open-spray systems shall be classified as 
high-probability systems. 

Exception: An indirect open-spray system shall not be 
required to be classified as a high-probability system if 
the pressure of the secondary coolant is at all times (op- 
erating and standby) greater than the pressure of the re- 
frigerant. 



SECTION 1104 
SYSTEM APPLICATION REQUIREMENTS 

1104.1 General. The refrigerant, occupancy and system clas- 
sification cited in this section shall be determined in accor- 
dance with Sections 1 103.1, 1 103.2 and 1 103.3, respectively. 
For refrigerant blends assigned dual classifications, as formu- 
lated and for the worst case of fractionation, the classifica- 
tions for the worst case of fractionation shall be used. 



82 



2003 INTERNATIONAL MECHANICAL CODE® 



REFRIGERATION 



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83 



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2003 INTERNATIONAL MECHANICAL CODE® 



REFRIGERATION 





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2003 INTERNATIONAL MECHANICAL CODE® 



85 



REFRIGERATION 



1104.2 Machinery room. Except as provided in Sections 
1 104.2. 1 and 1 104.2.2, all components containing the refriger- 
ant shall be located either outdoors or in a machinery room 
where the quantity of refrigerant in an independent circuit of a 
system exceeds the amounts shown in Table 1103.1. For refrig- 
erant blends not listed in Table 1103.1, the same requirement 
shall apply when the amount for any blend component exceeds 
that indicated in Table 1 103. 1 for that component. This require- 
ment shall also apply when the combined amount of the blend 
components exceeds a limit of 69,100 parts per million (ppm) 
by volume. Machinery rooms required by this section shall be 
constructed and maintained in accordance with Section 1105 
for Group Al and Bl refrigerants and in accordance with Sec- 
tions 1 105 and 1 106 for Group A2, B2, A3 and B3 refrigerants. 

Exceptions: 

1. Machinery rooms are not required for listed equip- 
ment and appliances containing not more than 6.6 
pounds (3 kg) of refrigerant, regardless of the refriger- 
ant's safety classification, where installed in accor- 
dance with the equipment's or appliance's listing and 
the equipment or appliance manufacturer's installa- 
tion instructions. 

2. Piping in conformance with Section 1107 is allowed 
in other locations to connect components installed in a 
machinery room with those installed outdoors. 

1104.2.1 Institutional occupancies. The amounts shown in 
Table 1 103.1 shall be reduced by 50 percent for all areas of 
institutional occupancies except kitchens, laboratories, and 
mortuaries. The total of all Group A2, B2, A3 and B3 refrig- 
erants shall not exceed 550 pounds (250 kg) in occupied ar- 
eas or machinery rooms. 

1104.2.2 Industrial occupancies and refrigerated rooms. 

This section applies only to industrial occupancies and re- 
frigerated rooms for manufacturing, food and beverage 
preparation, meat cutting, other processes and storage. Ma- 
chinery rooms are not required where all of the following 
conditions are met: 

1 . The space containing the machinery is separated from 
other occupancies by tight construction with tight-fit- 
ting doors. 

2. Access is restricted to authorized personnel. 



3 . The floor area per occupant is not less than 1 00 square 
feet (9.3 m^) where machinery is located on floor lev- 
els with exits more than 6.6 feet (2012 mm) above the 
ground. Where provided with egress directly to the 
outdoors or into approved building exits, the mini- 
mum floor area shall not apply. 

4. Refrigerant detectors are installed as required for ma- 
chinery rooms in accordance with Section 1105.3. 

5. Surfaces having temperatures exceeding 800°F 
(427°C) and open flames are not present where any 
Group A2, B2, A3 or B3 refrigerant is used (see Sec- 
tion 1104.3.4). 

6. All electrical equipment and appliances conform to 
Class 1, Division 2, hazardous location classification 
requirements of NFPA 70 where the quantity of any 
Group A2, B2, A3 or B3 refrigerant in a single inde- 
pendent circuit would exceed 25 percent of the lower 
flanmiability limit (LFL) upon release to the space. 

7. All refrigerant-containing parts in systems exceeding 
100 hp (74.6 kW) drive power, except evaporators 
used for refrigeration or dehumidification; condens- 
ers used for heating; control and pressure relief valves 
for either; and connecting piping, shall be located ei- 
ther outdoors or in a machinery room. 

1104.3 Refrigerant restrictions. Refrigerant applications, 
maximum quantities and use shall be restricted in accordance 
with Sections 1104.3.1 through 1104.3.4. 

1104.3.1 Air-conditioning for human comfort. In other 
than industrial occupancies where the quantity in a single in- 
dependent circuit does not exceed the amount in Table 
1 103. 1 , Group B 1 , B2 and B3 refrigerants shall not be used 
in high-probability systems for air-conditioning for human 
comfort. 

1104.3.2 Nonindustrial occupancies. Group A2 and B2 re- 
frigerants shall not be used in high-probability systems 
where the quantity of refrigerant in any independent refrig- 
erant circuit exceeds the amount shown in Table 1104.3.2. 
Group A3 and B3 refrigerants shall not be used except 
where approved. 

Exception: This section does not apply to laboratories 
where the floor area per occupant is not less than 100 
square feet (9.3 m^). 



TABLE 1104.3.2 
MAXIMUM PERMISSIBLE QUANTITIES OF REFRIGERANTS 



TYPE OF REFRIGERATION SYSTEM 


MAXIMUM POUNDS FOR VARIOUS OCCUPANCIES 


institutional 


Assembly 


Residential 


All other occupancies 


Sealed absorption system 

In exit access 

In adjacent outdoor locations 

In other than exit access 











6.6 


3.3 
22 
6.6 


3.3 
22 
6.6 


Unit systems 

In other than exit access 








6.6 


6.6 



For SI: 1 pound = 0.454 kg. 



86 



2003 INTERNATIONAL MECHANICAL CODE® 



REFRIGERATION 



• 



1104.3.3 All occupancies. The total of all Group A2, B2, 
A3 and B3 refrigerants other than R-717, ammonia, shall 
not exceed 1,100 pounds (499 kg) except where approved. 

1104.3.4 Protection from refrigerant decomposition. 

Where any device having an open flame or surface tempera- 
ture greater than 800°F (427°C) is used in a room containing 
more than 6.6 pounds (3 kg) of refrigerant in a single inde- 
pendent circuit, a hood and exhaust system shall be provided 
in accordance with Section 510. Such exhaust system shall 
exhaust combustion products to the outdoors. 

Exception: A hood and exhaust system shall not be re- 
quired: 

1. Where the refrigerant is R-717, R-718, or R-744; 

2. Where the combustion air is ducted from the out- 
doors in a manner that prevents leaked refrigerant 
from being combusted; or 

3. Where a refrigerant detector is used to stop the 
combustion in the event of a refrigerant leak (see 
Sections 1105.3 and 1105.5). 

1104.4 Volume calculations. Volume calculations shall be in 
accordance with Sections 1104.4.1 through 1104.4.3. 

1104.4.1 Noncommunicating spaces. Where the refriger- 
ant-containing parts of a system are located in one or more 
spaces that do not communicate through permanent open- 
ings or HVAC ducts, the volume of the smallest, enclosed 
occupied space shall be used to determine the permissible 
quantity of refrigerant in the system. 

1104.4.2 Communicating spaces. Where an evaporator or 
condenser is located in an air duct system, the volume of the 
smallest, enclosed occupied space served by the duct system 
shall be used to determine the maximum allowable quantity 
of refrigerant in the system. 

Exception: If airflow to any enclosed space cannot be re- 
duced below one-quarter of its maximum, the entire 
space served by the air duct system shall be used to deter- 
mine the maximum allowable quantity of refrigerant in 
the system. 

1104.4.3 Plenums. Where the space above a suspended 
ceiling is continuous and part of the supply or return air ple- 
num system, this space shall be included in calculating the 
volume of the enclosed space. 



SECTION 1105 
MACHINERY ROOM, GENERAL REQUIREMENTS 

[B] 1105.1 Design and construction. Machinery rooms shall 
be designed and constructed in accordance with the Interna- 
tional Building Code and this section. 

1105.2 Openings. Ducts and air handlers in the machinery room 
that operate at a lower pressure than the room shall be sealed to 
prevent any refrigerant leakage from entering the airstream. 

[F] 1105.3 Refrigerant detector. Refrigerant detectors in ma- 
chinery rooms shall be provided as required by the Interna- 
tional Fire Code, 



1105.4 Tests. Periodic tests of the mechanical ventilating sys- 
tem shall be performed in accordance with manufacturer's 
specifications and as required by the code official. 

1105.5 Fuel-burning appliances. Open flames that use com- 
bustion air from the machinery room shall not be installed in a 
machinery room. 

Exceptions: 

1. Matches, lighters, halide leak detectors and similar 
devices. 

2. Where the refrigerant is carbon dioxide or water. 

3. Fuel-burning appliances shall not be prohibited in the 
same machinery room with refrigerant-containing 
equipment or appliances where combustion air is 
ducted from outside the machinery room and sealed in 
such a manner as to prevent any refrigerant leakage 
from entering the combustion chamber, or where a re- 
frigerant vapor detector is employed to automatically 
shut off the combustion process in the event of refrig- 
erant leakage. 

1105.6 Ventilation. Machinery rooms shall be mechanically 
ventilated to the outdoors. Mechanical ventilation shall be ca- 
pable of exhausting the minimum quantity of air both at normal 
operating and emergency conditions. Multiple fans or 
multispeed fans shall be allowed in order to produce the emer- 
gency ventilation rate and to obtain a reduced airflow for nor- 
mal ventilation. 

Exception: Where a refrigerating system is located outdoors 
more than 20 feet (6096 mm) from any building opening and 
is enclosed by a penthouse, lean-to or other open structure, 
natural or mechanical ventilation shall be provided. Location 
of the openings shall be based on the relative density of the re- 
frigerant to air. The free-aperture cross section for the ventila- 
tion of the machinery room shall be not less than: 



(Equation 11-1) 



ForSI:F= 0138 Vg 

where: 

F = The free opening area in square feet (m^). 

G = The mass of refrigerant in pounds (kg) in the largest 
system, any part of which is located in the machinery 
room. 

1105.6.1 Discharge location. The discharge of the air shall 
be to the outdoors in accordance with Chapter 5. Exhaust 
from mechanical ventilation systems shall be discharged not 
less than 20 feet (6096 nmi) from a property Hne or openings 
into buildings. 

1105.6.2 Makeup air. Provisions shall be made for makeup 
air to replace that being exhausted. Openings for makeup air 
shall be located to avoid intake of exhaust air. Supply and 
exhaust ducts to the machinery room shall serve no other 
area, shall be constructed in accordance with Chapter 5 and 
shall be covered with corrosion-resistant screen of not less 
than V4-inch (6.4 mm) mesh. 



2003 INTERNATIONAL MECHANICAL CODE® 



87 



REFRIGERATION 



1105.6.3 Quantity — normal ventilation. During occupied 
conditions, the mechanical ventilation system shall exhaust 
the larger of the following: 

1. Not less than 0.5 cfm per square foot (0.0025 mVs • 
m^) of machinery room area or 20 cfm (0.009 mVs) 
per person; or 

2. A volume required to limit the room temperature rise 
to 18°F (10°C) taking into account the ambient heat- 
ing effect of all machinery in the room. 

1105.6.4 Quantity — emergency conditions. Upon actua- 
tion of the refrigerant detector required in Section 1105.3, 
the mechanical ventilation system shall exhaust air from the 
machinery room in the following quantity: 



(Equation 11-2) 



e=100xVG 

For SI: Q = 0.07 x Vg 

where: 

Q = The airflow in cubic feet per minute (mVs). 

G = The design mass of refrigerant in pounds (kg) in the 
largest system, any part of which is located in the 
machinery room. 

1105.7 Termination of relief devices. Pressure rehef devices, 
fusible plugs and purge systems located within the machinery 
room shall terminate outside of the structure at a location not 
less than 1 5 feet (4572 mm) above the adjoining grade level and 
not less than 20 feet (6096 mm) from any window, ventilation 
opening or exit. 

1105.8 Ammonia discharge. Pressure relief valves for ammo- 
nia systems shall discharge in accordance with ASHRAE 15. 



SECTION 1106 
MACHINERY ROOM, SPECIAL REQUIREMENTS 

1106.1 General. Where required by Section 1104.2, the ma- 
chinery room shall meet the requirements of this section in ad- 
dition to the requirements of Section 1 105. 

1106.2 Elevated temperature. There shall not be an open 
flame-producing device or continuously operating hot surface 
over 800*^F (427 °C) permanently installed in the room. 

1106.3 Ammonia room ventilation. Ventilation systems in 
ammonia machinery rooms shall be operated continuously. 

Exceptions: 

1 . Machinery rooms equipped with a vapor detector that 
will automatically start the ventilation system and ac- 
tuate an alarm at a detection level not to exceed 1,000 
ppm; or 

2. Machinery rooms conforming to the Class 1 , Division 
2, hazardous location classification requirements of 
NFPA 70. 

1106.4 Flammable refrigerants. Where refrigerants of 
Groups A2, A3, B2 and B3 are used, the machinery room shall 
conform to the Class 1 , Division 2, hazardous location classifi- 
cation requirements of NFPA 70. 

Exception: Ammonia machinery rooms. 



[F] 1106.5 Remote controls. Remote control of the mechani- 
cal equipment and appliances located in the machinery room 
shall be provided as required by the International Fire Code. 

[F 1106.5.1 Refrigeration system. A clearly identified 
switch of the break-glass type shall provide off-only control 
of all electrically energized equipment and appliances in the 
machinery room, other than refrigerant leak detectors and 
machinery room ventilation. 

[F 1106.5.2 Ventilation system. A clearly identified switch 
of the break-glass type shall provide on-only control of the 
machinery room ventilation fans. 

[F]1106.6 Emergency signs and labels. Refrigeration units 
and systems shall be provided with approved emergency signs, 
charts, and labels in accordance with the International Fire 
Code. 



SECTION 1107 
REFRIGERANT PIPING 

1107.1 General. All refrigerant piping shall be installed, tested 
and placed in operation in accordance with this chapter. 

1107.2 Pipe enclosures. Rigid or flexible metal enclosures or 
pipe ducts shall be provided for soft, annealed copper tubing 
and used for refrigerant piping erected on the premises and con- 
taining other than Group Al or Bl refrigerants. Enclosures 
shall not be required for connections between condensing units 
and the nearest riser box(es)i provided such connections do not 
exceed 6 feet (1829 mm) in length. 

1107.3 Condensation. All refrigerating piping and fittings, 
brine piping and fittings that, during normal operation, will reach 
a surface temperature below the dew point of the surrounding air, 
and are located in spaces or areas where condensation will cause 
a safety hazard to the building occupants, structure, electrical 
equipment or any other equipment or appliances, shall be pro- 
tected in an approved manner to prevent such damage. 

1107.4 Materials for refrigerant pipe and tubing. Piping 
materials shall be as set forth in Sections 1107.4.1 through 
1107.4.5. 

1107.4.1 Steel pipe. Carbon steel pipe with a wall thickness 
not less than Schedule 80 shall be used for Group A2, A3, 
B2 or B3 refrigerant liquid lines for sizes 1 .5 inches (38 nrni) 
and smaller. Carbon steel pipe with a wall thickness not less 
than Schedule 40 shall be used for Group Al or B 1 refriger- 
ant liquid lines 6 inches (152 mm) and smaller, Group A2, 
A3, B2 or B3 refrigerant liquid lines sizes 2 inches (5 1 mm) 
through 6 inches (152 mm) and all refrigerant suction and 
discharge lines 6 inches (152 mm) and smaller. Type F steel 
pipe shall not be used for refrigerant lines having an operat- 
ing temperature less than -20T (-29°C). 

1107.4.2 Copper and brass pipe. Standard iron-pipe size, 
copper and red brass (not less than 80-percent copper) pipe 
shall conform to ASTM B 42 and ASTM B 43. 

1107.4.3 Copper tube. Copper tube used for refrigerant pip- 
ing erected on the premises shall be seamless copper tube of 
Type ACR (hard or annealed) complying with ASTM B 280. 
Where approved, copper tube for refrigerant piping erected 
on the premises shall be seamless copper tube of Type K, L or 



88 



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M (drawn or annealed) in accordance with ASTM B 88. An- 
nealed temper copper tube shall not be used in sizes larger 
than a 2-inch (51 mm) nominal size. Mechanical joints shall 
not be used on annealed temper copper tube in sizes larger 
than Vg-inch (22.2 mm) OD size. 

1107.4.4 Copper tubing joints. Copper tubing joints used in 
refrigerating systems containing Group A2, A3, B2 or B3 re- 
frigerants shall be brazed. Soldered joints shall not be used in 
such refrigerating systems. 

1107.4.5 Aluminum tube. Type 3003-0 aluminum tubing 
with high-pressure fittings shall not be used with methyl 
chloride and other refrigerants known to attack aluminum. 

1107.5 Joints and refrigerant-containing parts in air ducts. 

Joints and all refrigerant-containing parts of a refrigerating sys- 
tem located in an air duct of an air-conditioning system carry- 
ing conditioned air to and from human-occupied space shall be 
constructed to withstand, without leakage, a pressure of 150 
percent of the higher of the design pressure or pressure relief 
device setting. 

1107.6 Exposure of refrigerant pipe joints. Refrigerant pipe 
joints erected on the premises shall be exposed for visual in- 
spection prior to being covered or enclosed. 

1107.7 Stop valves. All systems containing more than 6.6 
pounds (3 kg) of a refrigerant in systems using positive-dis- 
placement compressors shall have stop valves installed as fol- 
lows: 

1. At the inlet of each compressor, compressor unit or con- 
densing unit. 

2. At the discharge outlet of each compressor, compressor 
unit or condensing unit and of each liquid receiver. 

Exceptions: 

1 . Systems that have a refrigerant pumpout function ca- 
pable of storing the entire refrigerant charge in a re- 
ceiver or heat exchanger. 

2. Systems that are equipped with provisions for 
pumpout of the refrigerant using either portable or 
permanently installed recovery equipment. 

3. Self-contained systems. 

1107.7.1 Liquid receivers. All systems containing 100 
pounds (45 kg) or more of a refrigerant, other than systems 
utilizing nonpositive displacement compressors, shall have 
stop valves, in addition to those required by Section 1 107.7, 
on each inlet of each liquid receiver. Stop valves shall not be 
required on the inlet of a receiver in a condensing unit, nor 
on the inlet of a receiver which is an integral part of the con- 
denser. 

1107.7.2 Copper tubing. Stop valves used with soft an- 
nealed copper tubing or hard-drawn copper tubing 7g-inch 
(22.2 mm) OD standard size or smaller shall be securely 
mounted, independent of tubing fastenings or supports. 

1107.7.3 Identification. Stop valves shall be identified 
where their intended purpose is not obvious. Numbers shall 
not be used to label the valves, unless a key to the numbers is 
located near the valves. 



SECTION 1108 
FIELD TEST 

1108.1 General. Every refrigerant-containing part of every sys- 
tem that is erected on the premises, except compressors, con- 
densers, vessels, evaporators, safety devices, pressure gauges 
and control mechanisms that are hsted and factory tested, shall 
be tested and proved tight after complete installation, and before 
operation. Tests shall include both the high- and low-pressure 
sides of each system at not less than the lower of the design pres- 
sures or the setting of the pressure relief device(s). The design 
pressures for testing shall be those listed on the condensing unit, 
compressor or compressor unit name-plate, as required by 
ASHRAE 15. 

Exceptions: 

1. Gas bulk storage tanks that are not permanently con- 
nected to a refrigeration system. 

2. Systems erected on the premises with copper tubing 
not exceeding Vg-inch (15.8 mm) OD, with wall thick- 
ness as required by ASHRAE 15, shall be tested in ac- 
cordance with Section 1108.1, or by means of 
refrigerant charged into the system at the saturated va- 
por pressure of the refrigerant at 70°F (21 °C) or 
higher. 

3. Limited-charge systems equipped with a pressure re- 
lief device, erected on the premises, shall be tested at a 
pressure not less than one and one-half times the pres- 
sure setting of the relief device. If the equipment or 
appliance has been tested by the manufacturer at one 
and one-half times the design pressure, the test after 
erection on the premises shall be conducted at the de- 
sign pressure. 

1108.1.1 Booster compressor. Where a compressor is used 
as a booster to obtain an intermediate pressure and dis- 
charges into the suction side of another compressor, the 
booster compressor shall be considered a part of the low 
side, provided that it is protected by a pressure relief device. 

1108.1.2 Centrifugal/nonpositive displacement com- 
pressors. In field-testing systems using centrifugal or other 
nonpositive displacement compressors, the entire system 
shall be considered as the low-side pressure for field test 
purposes. 

1108.2 Test gases. Tests shall be performed with an inert dried 
gas including, but not limited to, nitrogen and carbon dioxide. 
Oxygen, air, combustible gases and mixtures containing such 
gases shall not be used. 

Exception: The use of air is allowed to test R-717, anrnio- 
nia, systems provided that they are subsequently evacuated 
before charging with refrigerant. 

1108.3 Test apparatus. The means used to build up the test 
pressure shall have either a pressure-limiting device or a pres- 
sure-reducing device and a gauge on the outlet side. 

1108.4 Declaration. A certificate of test shall be provided for 
all systems containing 55 pounds (25 kg) or more of refriger- 
ant. The certificate shall give the name of the refrigerant and the 
field test pressure applied to the high side and the low side of 
the system. The certification of test shall be signed by the in- 
staller and shall be made part of the public record. 



2003 INTERNATIONAL MECHANICAL CODE® 



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REFRIGERATION 



[F]SECTION1109 
PERIODIC TESTING 

1109.1 Testing required. The following emergency devices 
and systems shall be periodically tested in accordance with the 
manufacturer's instructions and as required by the code offi- 
cial: 

1. Treatment and flaring systems. 

2. Valves and appurtenances necessary to the operation of 
emergency refrigeration control boxes. 

3 . Fans and associated equipment intended to operate emer- 
gency pure ventilation systems. 

4. Detection and alarm systems. 



90 2003 INTERNATIONAL MECHANICAL CODE® 



• 



CHAPTER 12 

HYDRONIC PIPING 



SECTION 1201 
GENERAL 

1201.1 Scope. The provisions of this chapter shall govern the 
construction, installation, alteration and repair of hydronic pip- 
ing systems. This chapter shall apply to hydronic piping sys- 
tems that are part of heating, ventilation and air-conditioning 
systems. Such piping systems shall include steam, hot water, 
chilled water, steam condensate and ground source heat pump 
loop systems. Potable cold and hot water distribution systems 
shall be installed in accordance with the International 
Plumbing Code. 

1201.2 Pipe sizing. Piping for hydronic systems shall be sized 
for the demand of the system. 

SECTION 1202 
MATERIAL 

1202.1 Piping. Piping material shall conform to the standards 
cited in this section. 

Exception: Embedded piping regulated by Section 1209. 

1202.2 Used materials. Reused pipe, fittings, valves or other 
materials shall be clean and free of foreign materials and shall 
be approved by the code official for reuse. 

1202.3 Material rating. Materials shall be rated for the operat- 
ing temperature and pressure of the hydronic system. Materials 
shall be suitable for the type of fluid in the hydronic system. 

1202.4 Piping materials standards. Hydronic pipe shall con- 
form to the standards listed in Table 1202.4. The exterior of the 
pipe shall be protected from corrosion and degradation. 



TABLE 1202.4 
HYDRONIC PIPE 



TABLE 1202.4— continued 
HYDRONIC PIPE 



MATERIAL 


STANDARD (see Chapter 15) 


Acrylonitrile butadiene styrene 
(ABS) plastic pipe 


ASTM D 1527; ASTM D 2282 


Brass pipe 


ASTM B 43 


Brass tubing 


ASTM B 135 


Copper or copper-alloy pipe 


ASTM B 42; ASTM B 302 


Copper or copper-alloy tube 
(TypeK,LorM) 


ASTM B 75; ASTM B 88; 
ASTM B 251 


Chlorinated polyvinyl chloride 
(CPVC) plastic pipe 


ASTM D 2846; ASTM F 441; 
ASTM F 442 


Cross-linked polyethylene/ 
aluminum/cross-linked 
polyethylene (PEX-AL-PEX) 
pressure pipe 


ASTM F 1281; 

CSACAN/CSA-B-137.10 


Cross-linked polyethylene 
(PEX) tubing 


ASTM F 876; ASTM F 877 



MATERIAL 


STANDARD (see Chapter 15) 


Lead pipe 


FS WW-P-325B 


Polybutylene (PB) plastic pipe 
and tubing 


ASTM D 3309 


Polyethylene (PE) pipe, tubing 
and fittings (for ground source 
heat pump loop systems) 


ASTM D 2513; ASTM D 3035; 
ASTM D 2447; ASTM D 2683; 
ASTM F 1055; ASTM D 2837; 
ASTM D 3350; ASTM D 1693 


Polyvinyl chloride (PVC) 
plastic pipe 


ASTM D 1785; ASTM D 2241 


Steel pipe 


ASTM A 53; ASTM A 106 


Steel tubing 


ASTM A 254 



1202.5 Pipe fittings. Hydronic pipe fittings shall be approved 
for installation with the piping materials to be installed, and 
shall conform to the respective pipe standards or to the stan- 
dards listed in Table 1202.5. 



TABLE 1202.5 
HYDRONIC PIPE FITTINGS 



MATERIAL 


STANDARD (see Chapter 15) 


Bronze 


ASMEB 16.24 


Copper and copper alloys 


ASMEB16.15;ASMEB16.18; 
ASMEB16.22;ASMEB16.23; 
ASME B 16.26; ASME B 16.29 


Gray iron 


ASTM A 126 


Malleable iron 


ASMEB 16.3 


Plastic 


ASTM D 2466; ASTM D 2467; 
ASTM D 2468; ASTM F 438; 
ASTM F 439; ASTM F 877 


Steel 


ASMEB 16.5; ASMEB 16.9; 
ASMEB16.il; ASMEB 16.28; 
ASTM A 420 


Brass 


ASTM F 1974 



1202.6 Valves. Valves shall be constructed of materials that are 
compatible with the type of piping material and fluids in the 
system. Valves shall be rated for the temperatures and pressures 
of the systems in which the valves are installed. 

1202.7 Flexible connectors, expansion and vibration com- 
pensators. Flexible connectors, expansion and vibration con- 
trol devices and fittings shall be of an approved type. 



(continued) 



2003 INTERNATIONAL MECHANICAL CODE® 



91 



HYDRONIC PIPING 



SECTION 1203 
JOINTS AND CONNECTIONS 

1203.1 Approval. Joints and connections shall be of an ap- 
proved type. Joints and connections shall be tight for the pres- 
sure of the hydronic system. 

1203.1.1 Joints between different piping materials. 

Joints between different piping materials shall be made with 
approved adapter fittings. Joints between different metallic 
piping materials shall be made with approved dielectric fit- 
tings or brass converter fittings. 

1203.2 Preparation of pipe ends. Pipe shall be cut square, 
reamed and chamfered, and shall be free of burrs and obstruc- 
tions. Pipe ends shall have full-bore openings and shall not be 
undercut. 

1203.3 Joint preparation and installation. When required by 
Sections 1203.4 through 1203.14, the preparation and installa- 
tion of brazed, mechanical, soldered, solvent-cemented, 
threaded and welded joints shall comply with Sections 
1203.3.1 through 1203.3.7. 

1203.3.1 Brazed joints. Joint surfaces shall be cleaned. An 
approved flux shall be applied where required. The joint 
shall be brazed with a filler metal conforming to AWS A5.8. 

1203.3.2 Mechanical joints. Mechanical joints shall be in- 
stalled in accordance with the manufacturer's instructions. 

1203.3.3 Soldered joints. Joint surfaces shall be cleaned. A 
flux conforming to ASTM B 813 shall be applied. The joint 
shall be soldered with a solder conforming to ASTM B 32. 

1203.3.4 Solvent-cemented joints. Joint surfaces shall be 
clean and free of moisture. An approved primer shall be ap- 
plied to CPVC and PVC pipe-joint surfaces. Joints shall be 
made while the cement is wet. Solvent cement conforming 
to the following standards shall be applied to all joint sur- 
faces: 

1. ASTM D 2235 for ABS joints. 

2. ASTM F 493 for CPVC joints. 

3. ASTM D 2564 for PVC joints. 

CPVC joints shall be made in accordance with ASTM D 
2846. 

1203.3.5 Threaded joints. Threads shall conform to ASME 
B 1 .20. 1 . Schedule 80 or heavier plastic pipe shall be threaded 
with dies specifically designed for plastic pipe. Thread lubri- 
cant, pipe-joint compound or tape shall be appHed on the 
male threads only and shall be approved for appUcation on 
the piping material. 

1203.3.6 Welded joints. Joint surfaces shall be cleaned by 
an approved procedure. Joints shall be welded with an ap- 
proved filler metal. 

1203.3.7 Grooved and shouldered joints. Grooved and 
shouldered joints shall be approved and installed in accor- 
dance with the manufacturer's installation instructions. 

1203.3.8 Mechanically formed tee fittings. Mechanically 
extracted outlets shall have a height not less than three times 
the thickness of the branch tube wall. 



1203.3.8.1 Full flow assurance. Branch tubes shall not re- 
strict the flow in the run tube. A dimple/depth stop shall be 
formed in the branch tube to ensure that penetration into the 
outlet is of the correct depth. For inspection purposes, a sec- 
ond dimple shall be placed 0.25 inch (6.4 mm) above the 
first dimple. Dimples shall be aligned with the tube run. 

1203.3.8.2 Brazed joints. Mechanically formed tee fittings 
shall be brazed in accordance with Section 1203.3.1. 

1203.4 ABS plastic pipe. Joints between ABS plastic pipe or 
fittings shall be solvent-cemented or threaded joints conform- 
ing to Section 1203.3. 

1203.5 Brass pipe. Joints between brass pipe or fittings shall 
be brazed, mechanical, threaded or welded joints conforming 
to Section 1203.3. 

1203.6 Brass tubing. Joints between brass tubing or fittings 
shall be brazed, mechanical or soldered joints conforming to 
Section 1203.3. 

1203.7 Copper or copper-alloy pipe. Joints between copper 
or copper-alloy pipe or fittings shall be brazed, mechanical, 
soldered, threaded or welded joints conforming to Section 
1203.3. 

1203.8 Copper or copper-alloy tubing. Joints between cop- 
per or copper-alloy tubing or fittings shall be brazed, mechani- 
cal or soldered joints conforming to Section 1203.3 or flared 
joints conforming to Section 1203.8.1. 

1203.8.1 Flared joints. Flared joints shall be made by a tool 
designed for that operation. 

1203.9 CPVC plastic pipe. Joints between CPVC plastic pipe 
or fittings shall be solvent-cemented or threaded joints con- 
forming to Section 1203.3. 

1203.10 Polybutylene plastic pipe and tubing. Joints between 
polybutylene plastic pipe and tubing or fittings shall be mechani- 
cal joints conforming to Section 1203.3 or heat-fusion joints 
conforming to Section 1203.10.1. 

1203.10.1 Heat-fusion joints. Joints shall be of the 
socket-fusion or butt-fusion type. Joint surfaces shall be clean 
and free of moisture. Joint surfaces shall be heated to melt 
temperatures and joined. The joint shall be undisturbed until 
cool. Joints shall be made in accordance with ASTM D 3309. 

1203.11 Cross-linked polyethylene (PEX) plastic tubing. 

Joints between cross-linked polyethylene plastic tubing and fit- 
tings shall conform to Sections 1203.11.1 and 1203.11.2. Me- 
chanical joints shall conform to Section 1203.3. 

1203.11.1 Compression-type fittings. When compres- 
sion-type fittings include inserts and ferrules or O-rings, the 
fittings shall be installed without omitting the inserts and 
ferrules or O-rings. 

1203.11.2 Plastic-to-metal connections. Soldering on the 
metal portion of the system shall be performed at least 18 
inches (457 mm) from a plastic-to-metal adapter in the same 
water line. 

1203.12 PVC plastic pipe. Joints between PVC plastic pipe 
and fittings shall be solvent-cemented or threaded joints con- 
forming to Section 1203.3. 



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• 



1203.13 Steel pipe. Joints between steel pipe or fittings shall be 
mechanical joints that are made with an approved elastomeric 
seal, or shall be threaded or welded joints conforming to Sec- 
tion 1203.3. 

1203.14 Steel tubing. Joints between steel tubing or fittings 
shall be mechanical or welded joints conforming to Section 
1203.3. 

1203.15 Polyethylene plastic pipe and tubing for ground 
source heat pump loop systems. Joints between polyethylene 
plastic pipe and tubing or fittings for ground source heat pump 
loop systems shall be heat fusion joints conforming to Section 

1203.15.1, electrofusion joints conforming to Section 

1203.15.2, or stab-type insertion joints conforming to Section 
1203.15.3. 

1203.15.1 Heat-fusion joints. Joints shall be of the 
socket-fusion, saddle-fusion or butt-fusion type, fabricated 
in accordance with the piping manufacturer's instructions. 
Joint surfaces shall be clean and free of moisture. Joint sur- 
faces shall be heated to melt temperatures and joined. The 
joint shall be undisturbed until cool. Fittings shall be manu- 
factured in accordance with ASTM D 2683. 

1203.15.2 Electrofusion joints. Joints shall be of the 
electrofusion type. Joint surfaces shall be clean and free of 
moisture, and scoured to expose virgin resin. Joint surfaces 
shall be heated to melt temperatures for the period of time 
specified by the manufacturer. The joint shall be undisturbed 
until cool. Fittings shall be manufactured in accordance with 
ASTM F 1055. 

1203.15.3 Stab-type insert fittings. Joint surfaces shall be 
clean and free of moisture. Pipe ends shall be chamfered and 
inserted into the fittings to full depth. Fittings shall be manu- 
factured in accordance with ASTM D 2513. 



SECTION 1204 
PIPE INSULATION 

1204.1 Insulation characteristics. Pipe insulation installed in 
buildings shall conform to the requirements of the International 
Energy Conservation Code, shall be tested in accordance with 
ASTM E 84 and shall have a maximum flame spread index of 25 
and a smoke-developed index not exceeding 450. Insulation in- 
stalled in an air plenum shall comply with Section 602.2.1. 

Exception: The maximum flame spread index and smoke- 
developed index shall not apply to one- and two-family 
dwellings. 

1204.2 Required thickness. Hydronic piping shall be insu- 
lated to the thickness required by the International Energy 
Conservation Code. 



SECTION 1205 
VALVES 

1205.1 Where required. Shutoff valves shall be installed in 
hydronic piping systems in the locations indicated in Sections 
1205.1.1 through 1205.1.6. 

1205.1.1 Heat exchangers. Shutoff valves shall be installed 
on the supply and return side of a heat exchanger. 



Exception: Shutoff valves shall not be required when 
heat exchangers are integral with a boiler; or are a com- 
ponent of a manufacturer's boiler and heat exchanger 
packaged unit and are capable of being isolated from the 
hydronic system by the supply and return valves required 
by Section 1005.1. 

1205.1.2 Central systems. Shutoff valves shall be installed 
on the building supply and return of a central utility system. 

1205.1.3 Pressure vessels. Shutoff valves shall be installed 
on the connection to any pressure vessel. 

1205.1.4 Pressure-reducing valves. Shutoff valves shall be 
installed on both sides of a pressure-reducing valve. 

1205.1.5 Equipment and appliances. Shutoff valves shall 
be installed on connections to mechanical equipment and ap- 
phances. This requirement does not apply to components of a 
hydronic system such as pumps, air separators, metering de- 
vices and similar equipment. 

1205.1.6 Expansion tanks. Shutoff valves shall be installed 
at connections to nondiaphragm-type expansion tanks. 

1205.2 Reduced pressure. A pressure relief valve shall be in- 
stalled on the low-pressure side of a hydronic piping system 
that has been reduced in pressure. The relief valve shall be set at 
the maximum pressure of the system design. The valve shall be 
installed in accordance with Section 1006. 



SECTION 1206 
PIPING INSTALLATION 

1206.1 General. Piping, valves, fittings and connections shall 
be installed in accordance with the conditions of approval. 

1206.1.1 Prohibited tee applications. Fluid in the supply 
side of a hydronic system shall not enter a tee fitting through 
the branch opening. 

1206.2 System drain down. Hydronic piping systems shall be 
designed and installed to permit the system to be drained. 
Where the system drains to the plumbing drainage system, the 
installation shall conform to the requirements of the Interna- 
tional Plumbing Code. 

1206.3 Protection of potable water. The potable water system 
shall be protected from backflow in accordance with the Inter- 
national Plumbing Code. 

1206.4 Pipe penetrations. Openings for pipe penetrations in 
walls, floors or ceihngs shall be larger than the penetrating pipe. 
Openings through concrete or masonry building elements shall be 
sleeved. The annular space surrounding pipe penetrations shall be 
protected in accordance with the International Building Code. 

1206.5 Clearance to combustibles. A pipe in a hydronic pip- 
ing system in which the exterior temperature exceeds 250°F 
(121 °C) shall have a minimum clearance of 1 inch (25 mm) to 
combustible materials. 

1206.6 Contact with building material. A hydronic piping 
system shall not be in direct contact with building materials 
that cause the piping material to degrade or corrode, or that in- 
terfere with the operation of the system. 



2003 INTERNATIONAL MECHANICAL CODE® 



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HYDRONPC PIPING 



1206.7 Water hammer. The flow velocity of the hydronic pip- 
ing system shall be controlled to reduce the possibility of water 
hammer. Where a quick-closing valve creates water hammer, 
an approved water-hammer arrestor shall be installed. The 
arrestor shall be located within a range as specified by the man- 
ufacturer of the quick-closing valve. 

1206.8 Steam piping pitch. Steam piping shall be installed to 
drain to the boiler or the steam trap. Steam systems shall not 
have drip pockets that reduce the capacity of the steam piping. 

1206.9 Strains and stresses. Piping shall be installed so as to 
prevent detrimental strains and stresses in the pipe. Provisions 
shall be made to protect piping from damage resulting from ex- 
pansion, contraction and structural settlement. Piping shall be 
installed so as to avoid structural stresses or strains within build- 
ing components. 

1206.9.1 Flood hazard. Piping located in a flood-hazard 
zone or high-hazard zone shall be capable of resisting hy- 
drostatic and hydrodynamic loads and stresses, including 
the effects of buoyancy, during the occurrence of flooding to 
the base flood elevation. 

1206.10 Pipe support. Pipe shall be supported in accordance 
with Section 305. 

1206.11 Condensation. Provisions shall be made to prevent 
the formation of condensation on the exterior of piping. 



SECTION 1209 
EMBEDDED PIPING 

1209.1 Materials. Piping for heating panels shall be stan- 
dard-weight steel pipe. Type L copper tubing, polybutylene or 
other approved plastic pipe or tubing rated at 100 psi (689 kPa) at 
180°F(82X). 

1209.2 Pressurizing during installation. Piping to be embed- 
ded in concrete shall be pressure tested prior to pouring con- 
crete. During pouring, the pipe shall be maintained at the 
proposed operating pressure. 

1209.3 Embedded joints. Joints of pipe or tubing that are em- 
bedded in a portion of the building, such as concrete or plaster, 
shall be in accordance with the requirements of Sections 
1209.3.1 through 1209.3.3. 

1209.3.1 Steel pipe joints. Steel pipe shall be welded by 
electrical arc or oxygen/acetylene method. 

1209.3.2 Copper tubing joints. Copper tubing shall be 
joined by brazing with filler metals having a melting point of 
not less than 1,000°F (538X). 

1209.3.3 Polybutylene joints. Polybutylene pipe and tub- 
ing shall be installed in continuous lengths or shall be joined 
by heat fusion in accordance with Section 1203.10.1. 

1209.4 Not embedded related piping. Joints of other piping in 
cavities or running exposed shall be joined by approved meth- 
ods in accordance with manufacturer's installation instructions 
and related sections of this code. 



SECTION 1207 
TRANSFER FLUID 

1207.1 Flash point. The flash point of transfer fluid in a 
hydronic piping system shall be a minimum of 50°F (28°C) 
above the maximum system operating temperature. 

1207.2 Makeup water. The transfer fluid shall be compatible 
with the makeup water supplied to the system. 



SECTION 1208 
TESTS 

1208.1 General. Hydronic piping systems other than ground- 
source heat pump loop systems shall be tested hydrostatically 
at one and one half times the maximum system design pressure, 
but not less than 100 psi (689 kPa). The duration of each test 
shall be not less than 15 minutes. Ground-source heat pump 
loop systems shall be tested in accordance with Section 
1208.1.1. 

1208.1.1 Ground source heat pump loop systems. Before 
connection (header) trenches are backfilled, the assembled 
loop system shall be pressure tested with water at 100 psi 
(689 kPa) for 30 minutes with no observed leaks. Flow and 
pressure loss testing shall be performed and the actual flow 
rates and pressure drops shall be compared to the calculated 
design values. If actual flow rate or pressure drop values dif- 
fer from calculated design values by more than 10 percent, 
the problem shall be identified and corrected. 



94 



2003 INTERNATIONAL MECHANICAL CODE® 



CHAPTER 13 

FUEL OIL PIPING AND STORAGE 



SECTION 1301 
GENERAL 

1301.1 Scope. This chapter shall govern the design, installa- 
tion, construction and repair of fuel-oil storage and piping sys- 
tems. The storage of fuel oil and flammable and combustible 
liquids shall be in accordance with the International Fire Code. 

1301.2 Storage and piping systems. Fuel-oil storage systems 
shall comply with the International Fire Code. Fuel-oil piping 
systems shall comply with the requirements of this code. 

1301.3 Fuel type. An appliance shall be designed for use with 
the type of fuel to which it will be connected. Such appliance 
shall not be converted from the fuel specified on the rating plate 
for use with a different fuel without securing reapproval from 
the code official. 

1301.4 Fuel tanks, piping and valves. The tank, piping and 
valves for appliances burning oil shall be installed in accor- 
dance with the requirements of this chapter. When an oil burner 
is served by a tank, any part of which is above the level of the 
burner inlet connection and where the fuel supply line is taken 
from the top of the tank, an approved antisiphon valve or other 
siphon-breaking device shall be installed in lieu of the shutoff 
valve. 



SECTION 1302 
MATERIAL 

1302.1 General. Piping materials shall conform to the stan- 
dards cited in this section. 

1302.2 Rated for system. All materials shall be rated for the 
operating temperatures and pressures of the system, and shall 
be compatible with the type of liquid. 

1302.3 Pipe standards. Fuel oil pipe shall comply with one of 
the standards listed in Table 1302.3. 



TABLE 1302.3 
FUEL OIL PIPING 



MATERIAL 


STANDARD (see Chapter 15) 


Brass pipe 


ASTM B 43 


Brass tubing 


ASTM B 135 


Copper or copper-alloy pipe 


ASTM B 42; ASTM B 302 


Copper or copper-alloy tubing 
(TypeK,LorM) 


ASTM B 75; ASTM B 88; 
ASTM B 280 


Labeled pipe 


(See Section 1302.4) 


Nonmetallic pipe 


ASTM D 2996 


Steel pipe 


ASTM A 53; ASTM A 106 


Steel tubing 


ASTM A 254; ASTM A 539 



1302.4 Nonmetallic pipe. All nonmetallic pipe shall be hsted 
and labeled as being acceptable for the intended application for 
flammable and combustible liquids. Nonmetalhc pipe shall be 
installed only outside, underground. 

1302.5 Fittings and valves. Fittings and, valves shall be ap- 
proved for the piping systems, and shall be compatible with, or 
shall be of the same material as, the pipe or tubing. 

1302.6 Bending of pipe. Pipe shall be approved for bending. 
Pipe bends shall be made with approved equipment. The bend 
shall not exceed the structural limitations of the pipe. 

1302.7 Pumps. Pumps that are not part of an appliance shall be 
of a positive-displacement type. The pump shall automatically 
shut off the supply when not in operation. Pumps shall be listed 
and labeled in accordance with UL 343. 

1302.8 Flexible connectors and hoses. Flexible connectors 
and hoses shall be listed and labeled in accordance with UL 
536. 



SECTION 1303 
JOINTS AND CONNECTIONS 

1303.1 Approval. Joints and connections shall be approved 
and of a type approved for fuel-oil piping systems. All threaded 
joints and connections shall be made tight with suitable lubri- 
cant or pipe compound. Unions requiring gaskets or packings, 
right or left couplings, and sweat fittings employing solder hav- 
ing a melting point of less than 1,000°F (538 °C) shall not be 
used in oil lines. Cast-iron fittings shall not be used. Joints and 
connections shall be tight for the pressure required by test. 

1303.1.1 Joints between different piping materials. Joints 
between different piping materials shall be made with ap- 
proved adapter fittings. Joints between different metallic pip- 
ing materials shall be made with approved dielectric fittings 
or brass converter fittings. 

1303.2 Preparation of pipe ends. All pipe shall be cut square, 
reamed and chamfered and be free of all burrs and obstructions . 
Pipe ends shall have full-bore openings and shall not be under- 
cut. 

1303.3 Joint preparation and installation. Where required 
by Sections 1303.4 through 1303.10, the preparation and in- 
stallation of brazed, mechanical, threaded and welded joints 
shall comply with Sections 1303.3.1 through 1303.3.4. 

1303.3.1 Brazed joints. All joint surfaces shall be cleaned. 
An approved flux shall be applied where required. The 
joints shall be brazed with a filler metal conforming to AWS 
A5.8. 

1303.3.2 Mechanical joints. Mechanical joints shall be in- 
stalled in accordance with the manufacturer's instructions. 



2003 INTERNATIONAL MECHANICAL CODE® 



95 



FUEL OIL PIPING AND STORAGE 



1303.3.3 Threaded joints. Threads shall conform to 
ASME B 1.20.1. Pipe-joint compound or tape shall be 
applied on the male threads only. 

1303.3.4 Welded joints. All joint surfaces shall be cleaned 
by an approved procedure. The joint shall be welded with an 
approved filler metal. 

1303.4 Brass pipe. Joints between brass pipe or fittings shall 
be brazed, mechanical, threaded or welded joints complying 
with Section 1303.3. 

1303.5 Brass tubing. Joints between brass tubing or fittings 
shall be brazed or mechanical joints complying with Section 
1303.3. 

1303.6 Copper or copper-alloy pipe. Joints between copper 
or copper-alloy pipe or fittings shall be brazed, mechanical, 
threaded or welded joints complying with Section 1303.3. 

1303.7 Copper or copper-alloy tubing. Joints between cop- 
per or copper-alloy tubing or fittings shall be brazed or me- 
chanical joints complying with Section 1303.3 or flared joints. 
Flared joints shall be made by a tool designed for that opera- 
tion. 

1303.8 Nonmetallic pipe. Joints between nonmetallic pipe or 
fittings shall be installed in accordance with the manufacturer's 
instructions for the labeled pipe and fittings. 

1303.9 Steel pipe. Joints between steel pipe or fittings shall be 
threaded or welded joints complying with Section 1303.3 or 
mechanical joints complying with Section 1303.9.1. 

1303.9.1 Mechanical joints. Joints shall be made with an 
approved elastomeric seal. Mechanical joints shall be in- 
stalled in accordance with the manufacturer's instructions. 
Mechanical joints shall be installed outside, underground, 
unless otherwise approved. 

1303.10 Steel tubing. Joints between steel tubing or fittings 
shall be mechanical or welded joints complying with Section 
1303.3. 

1303.11 Piping protection. Proper allowance shall be made 
for expansion, contraction, jarring and vibration. Piping other 
than tubing, connected to underground tanks, except straight 
fill lines and test wells, shall be provided with flexible connec- 
tors, or otherwise arranged to permit the tanks to settle without 
impairing the tightness of the piping connections. 



SECTION 1304 
PIPING SUPPORT 

1304.1 General. Pipe supports shall be in accordance with 
Section 305. 



have 0.035-inch (0.9 mm) nominal and 0.032-inch (0.8 mm) 
minimum wall thickness. 

1305.2 Protection of pipe, equipment and appliances. All 

fuel oil pipe, equipment and appliances shall be protected from 
physical damage. 

1305.2.1 Flood hazard. All fuel oil pipe, equipment and 
appliances located in flood hazard areas shall be located 
above the design flood elevation or shall be capable of re- 
sisting hydrostatic and hydrodynamic loads and stresses, in- 
cluding the effects of buoyancy, during the occurrence of 
flooding to the design flood elevation. 

1305.3 Supply piping. Supply piping shall connect to the top 
of the fuel oil tank. Fuel oil shall be supplied by a transfer pump 
or automatic pump or by other approved means. 

Exception: This section shall not apply to inside or 
above-ground fuel oil tanks. 

1305.4 Return piping. Return piping shall connect to the top 
of the fuel oil tank. Valves shall not be installed on return pip- 
ing. 

1305.5 System pressure. The system shall be designed for the 
maximum pressure required by the fuel-oil-buming apphance. 
Air or other gases shall not be used to pressurize tanks. 

1305.6 Fill piping. A fill pipe shall terminate outside of a build- 
ing at a point at least 2 feet (610 mm) from any building open- 
ing at the same or lower level. A fill pipe shall terminate in a 
manner designed to minimize spilling when the filling hose is 
disconnected. Fill opening shall be equipped with a tight metal 
cover designed to discourage tampering. 

1305.7 Vent piping. Liquid fuel vent pipes shall terminate outside 
of buildings at a point not less than 2 feet (610 mm) measured ver- 
tically or horizontally from any building opening. Outer ends of 
vent pipes shall terminate in a weatherproof vent cap or fitting or 
be provided with a weatherproof hood. All vent caps shall have a 
minimum free open area equal to the cross-sectional area of the 
vent pipe and shdl not employ screens finer than No. 4 mesh. Vent 
pipes shall terminate sufficiently above the ground to avoid being 
obstructed with snow or ice. Vent pipes from tanks containing 
heaters shall be extended to a location where oil vapors discharg- 
ing from the vent will be readily diffused. If the static head with a 
vent pipe filled with oil exceeds 10 pounds per square inch (psi) 
(69 kPa), the tank shall be designed for the maximum static head 
that will be imposed. 

Liquid fuel vent pipes shall not be cross connected with fill 
pipes, lines from burners or overflow lines from auxiliary 
tanks. 



SECTION 1305 
FUEL OIL SYSTEM INSTALLATION 

1305.1 Size. The fuel oil system shall be sized for the maximum 
capacity of fuel oil required. The minimum size of a supply hne 
shall be Vg-inch (9.5 nmi) inside diameter nominal pipe or 
Vg-inch (9.5 nun) OD tubing. The minimum size of a return line 
shall be V4-inch (6.4 mm) inside diameter nominal pipe or 
Vig-inch (7.9 mm) outside diameter tubing. Copper tubing shall 



SECTION 1306 
OIL GAUGING 

1306.1 Level indication. All tanks in which a constant oil level 
is not maintained by an automatic pump shall be equipped with 
a method of determining the oil level. 

1306.2 Test wells. Test wells shall not be installed inside build- 
ings. For outside service, test wells shall be equipped with a 
tight metal cover designed to discourage tampering. 



96 



2003 INTERNATIONAL MECHANICAL CODE® 



FUEL OIL PIPING AND STORAGE 



1306.3 Inside tanks. The gauging of inside tanks by means of 
measuring sticks shall not be permitted. An inside tank pro- 
vided with fill and vent pipes shall be provided with a device to 
indicate either visually or audibly at the fill point when the oil in 
the tank has reached a predetermined safe level. 

1306.4 Gauging devices. Gauging devices such as liquid level 
indicators or signals shall be designed and installed so that oil 
vapor will not be discharged into a building from the liquid fuel 
supply system. 

1306.5 Gauge glass. A tank used in connection with any oil 
burner shall not be equipped with a glass gauge or any gauge 
which, when broken, will permit the escape of oil from the tank. 



SECTION 1307 
FUEL OIL VALVES 

1307.1 Building shuto^. A shutoff valve shall be installed on 
the fuel-oil supply line at the entrance to the building. Inside or 
above-ground tanks are permitted to have valves installed at the 
tank. The valve shall be capable of stopping the flow of fuel oil 
to the building or to the appliance served where the valve is in- 
stalled at a tank inside the building. 

1307.2 Appliance shutoff. A shutoff valve shall be installed at 
the connection to each appliance where more than one 
fuel-oil-buming appliance is installed. 

1307.3 Pump relief valve. A rehef valve shall be installed on 
the pump discharge line where a valve is located downstream of 
the pump and the pump is capable of exceeding the pressure 
limitations of the fuel oil system. 

1307.4 Fuel-oil heater relief valve. A relief valve shall be in- 
stalled on the discharge line of fuel-oil-heating appliances. 

1307.5 Relief valve operation. The relief valve shall discharge 
fuel oil when the pressure exceeds the limitations of the system. 
The discharge line shall connect to the fuel oil tank. 



SECTION 1308 
TESTING 

1308.1 Testing required. Fuel oil piping shall be tested in ac- 
cordance with NFPA 3 1 . 



2003 INTERNATIONAL MECHANICAL CODE® 



97 



98 2003 INTERNATIONAL MECHANICAL CODE® 



CHAPTER 14 

SOLAR SYSTEMS 



SECTION 1401 
GENERAL 

1401.1 Scope. This chapter shall govern the design, construc- 
tion, installation, alteration and repair of systems, equipment and 
appliances intended to utiHze solar energy for space heating or 
cooling, domestic hot water heating, swimming pool heating or 
process heating. 

1401.2 Potable water supply. Potable water supplies to solar 
systems shall be protected against contamination in accordance 
with the International Plumbing Code. 

Exception: Where all solar system piping is a part of the po- 
table water distribution system, in accordance with the re- 
quirements of the International Plumbing Code, and all 
components of the piping system are listed for potable water 
use, cross-connection protection measures shall not be re- 
quired. 

1401.3 Heat exchangers. Heat exchangers used in domestic 
water-heating systems shall be approved for the intended use. 
The system shall have adequate protection to ensure that the 
potability of the water supply and distribution system is 
properly safeguarded. 

1401.4 Solar energy equipment and appliances. Solar en- 
ergy equipment and appliances shall conform to the require- 
ments of this chapter and shall be installed in accordance with 
the manufacturer's installation instructions. 

1401.5 Ducts. Ducts utilized in solar heating and cooling sys- 
tems shall be constructed and installed in accordance with 
Chapter 6 of this code. 



SECTION 1402 
INSTALLATION 

1402.1 Access. Access shall be provided to solar energy equip- 
ment and appliances for maintenance. Solar systems and ap- 
purtenances shall not obstruct or interfere with the operation of 
any doors, windows or other building components requiring 
operation or access. 

1402.2 Protection of equipment. Solar equipment exposed to 
vehicular traffic shall be installed not less than 6 feet (1829 
mm) above the finished floor. 

Exception: This section shall not apply where the equip- 
ment is protected from motor vehicle impact. 

1402.3 Controlling condensation. Where attics or structural 
spaces are part of a passive solar system, ventilation of such 
spaces, as required by Section 406, is not required where other 
approved means of controlling condensation are provided. 

1402.4 Roof-mounted collectors. Roof-mounted solar collec- 
tors that also serve as a roof covering shall conform to the re- 
quirements for roof coverings in accordance with the 
International Building Code, 



Exception: The use of plastic solar collector covers shall be 
limited to those approved plastics meeting the requirements 
for plastic roof panels in the International Building Code. 

1402.4.1 Collectors mounted above the roof. When 
mounted on or above the roof covering, the collector array 
and supporting construction shall be constructed of 
noncombustible materials or fire-retardant-treated wood 
conforming to the International Building Code to the extent 
required for the type of roof construction of the building to 
which the collectors are accessory. 

Exception: The use of plastic solar collector covers shall 
be limited to those approved plastics meeting the requyre- 
ments for plastic roof panels in the International Build- 
ing Code. 

1402.5 Equipment. The solar energy system shall be equipped in 
accordance with the requirements of Sections 1402.5.1 tiirough 
1402.5.4. 

1402.5.1 Pressure and temperature. Solar energy system 
components containing pressurized fluids shall be protected 
against pressures and temperatures exceeding design hmita- 
tions with a pressure and temperature relief valve. Each section 
of the system in which excessive pressures are capable of de- 
veloping shall have a relief device located so that a section can- 
not be valved off or otherwise isolated from a reUef device. 
Relief valves shall comply with the requirements of Section 
1006.4 and discharge in accordance with Section 1006.6. 

1402.5.2 Vacuum. The solar energy system components 
that are subjected to a vacuum while in operation or during 
shutdown shall be designed to withstand such vacuum or 
shall be protected with vacuum relief valves. 

1402.5.3 Protection from freezing. System components 
shall be protected from damage by freezing of heat transfer 
liquids at the lowest ambient temperatures that will be en- 
countered during the operation of the system. 

1402.5.4 Expansion tanks. Liquid single-phase solar en- 
ergy systems shall be equipped with expansion tanks sized 
in accordance with Section 1009. 

1402.6 Penetrations. Roof and wall penetrations shall be 
flashed and sealed to prevent entry of water, rodents and in- 
sects. 

1402.7 Filtering. Air transported to occupied spaces through 
rock or dust-producing materials by means other than natural 
convection shall be filtered at the outlet from the heat storage 
system. 



SECTION 1403 
HEAT TRANSFER FLUIDS 

1403.1 Flash point. The flash point of the actual heat transfer I 
fluid utilized in a solar system shall be not less than 50°F (28°C) I 



2003 INTERNATIONAL MECHANICAL CODE® 



99 



SOLAR SYSTEMS 



I 



above the design maximum nonoperating (no-flow) temperature 
of the fluid attained in the collector. 

1403.2 Flammable gases and liquids. A flammable liquid or 
gas shall not be utilized as a heat transfer fluid. The flash point 
of liquids used in occupancies classified in Group H or F shall 
not be lower unless approved. 



SECTION 1404 
MATERIALS 

1404.1 Collectors. Factory-built collectors shall be listed and 
labeled, and bear a label showing the manufacturer's name and 
address, model number, collector dry weight, collector maxi- 
mum allowable operating and nonoperating temperatures and 
pressures, minimum allowable temperatures and the types of 
heat transfer fluids that are compatible with the collector. The 
label shall clarify that these specifications apply only to the 
collector. 

1404.2 Thermal storage units. Pressurized thermal storage 
units shall be listed and labeled, and bear a label showing the 
manufacturer's name and address, model number, serial num- 
ber, storage unit maximum and minimum allowable operating 
temperatures, storage unit maximum and minimum allowable 
operating pressures and the types of heat transfer fluids com- 
patible with the storage unit. The label shall clarify that these 
specifications apply only to the thermal storage unit. 



100 2003 INTERNATIONAL MECHANICAL CODE® 



CHAPTER 15 

REFERENCED STANDARDS 



This chapter lists the standards that are referenced in various sections of this document. The standards are Usted herein by the 
promulgating agency of the standard, the standard identification, the effective date and title, and the section or sections of this 
document that reference the standard. The application of the referenced standards shall be as specified in Section 102.8. 



ACCA 



Air Conditioning Contractors of America 
1712 New Hampshire Ave, NW 
Washington, DC 20009 



Standard 

Reference 

Number 



Title 



Referenced 

in code 

section number 



Manual D— 95 



Residential Duct Systems 603.2 



ANSI 



American National Standards Institute 
1 1 West 42nd Street 
New York, NY 10036 



Standard 
reference 
number 


Title 


Referenced 

in code 

section number 


Z2 1.8— 1994 


Installation of Domestic Gas Conversion Burners 


919 1 


Z21.83— 1998 


Fuel Cell Power Plants 


924 1 









ARI 



Air-Conditioning and Refrigeration Institute 

Suite 425 

4301 North Fairfax Drive 

Arlington, VA 22203 



Standard 

Reference 

Number 



Title 



Referenced 

in code 

section number 



700—95 



Specifications for Fluorocarbon and Other Refrigerants 1 102.2.2.3 



ASHRAE 



ASHRAE— 2001 
15—2001 
34—2001 
ASHRAE— 2000 



American Society of Heating, Refrigerating 
and Air-Conditioning Engineers, Inc. 
1791 Tullie Circle, NE 
Atlanta, GA 30329-2305 

Title 

ASHRAE Fundamentals Handbook— 2001 312.1, 603.2 

Safety Standard for Refrigeration Systems 1 101.6, 1 105.8, 1 108.1 

Designation and Safety Classification of Refrigerants 202, 1102.2.1, 1103.1 

HVAC Systems and Equipment Handbook— 2000 312.1 



Standard 




Referenced 


Reference 




in code 


Number 


Title 


section number 



ASME 



Bl.20.1— 1983(R1999) 
B16.3— 1999 
B 16.5— 1996 



American Society of Mechanical Engineers 

Three Park Avenue 

New York, NY 10016-5990 

Title 

Pipe Threads, General Purpose (Inch) 1203.3.5, 1303.3.3 

Malleable Iron Threaded Fittings, Classes 150 & 300 Table 1202.5 

Pipe Flanges and Flanged Fittings NPS Vi through NPS 24 — 
With B16.5a-1998 Addenda Table 1202.5 



Standard 




Referenced 


Reference 




in code 


Number 


Title 


section number 



2003 INTERNATIONAL MECHANICAL CODE® 



101 



REFERENCED STANDARDS 



B16.9— 1993 
B16.il— 1996 
B16.15— 1985(R1994) 
B16.18— 1984(R1994) 
B16.22— 1995 

B16.23— 1992 

B 16.24— 1991 (R1998) 

B 16.26— 1988 

B 16.28— 1994 

B16.29— 1994 

BPVC— 1998 

CSD-1— 1998 



ASME — continued 

Factory Made Wrought Steel Buttwelding Fittings Table 1202.5 

Forged Fittings, Socket- Welding and Threaded Table 1202.5 

Cast Bronze Threaded Fittings Table 1202.5 

Cast Copper Alloy Solder Joint Pressure Fittings 513.13.1, Table 1202.5 

Wrought Copper and Copper Alloy Solder Joint Pressure 

Fittings— with B16.22a-1998 Addenda 513.13.1, Tabl e 1202.5 

Cast Copper Alloy Solder Joint Drainage Fittings DWV Table 1202.5 

Cast Copper Alloy Pipe Flanges and Hanged Fittings: Class 150, 300, 400, 600, 900, 1500 and 2500 Table 1202.5 

Cast Copper Alloy Fittings for Flared Copper Tubes Table 1202.5 

Wrought Steel Buttwelding Short Radius Elbows and Returns Table 1202.5 

Wrought Copper and Wrought Copper Alloy Solder Joint Drainage Fittings-DWV Table 1202,5 

Boiler & Pressure Vessel Code (Sections I, II, IV, V & VI) 1004.1, 1011.1 

Controls and Safety Devices for Automatically Fired Boilers 1004.1 



ASTM 



ASTM International 

100 Barr Harbor Drive 

West Conshohocken, PA 19428 



Standard 




Referenced 


Reference 




in code 


Number 


Title 


section number 



A 53/A 53M— 01 

A 106— 99el 
A 126--01 
A 254—97 
A420/A420M— 01 

A 539—99 
B 32—00 
B 42—98 
B 43—98 
B 68—99 
B 75—99 
B 88— 99el 
B 135—00 
B 251—97 
B 280— 99el 

B 302—00 
B 813— OOeOl 
C 315—00 
C 41 1—97 
D56— 01 
D93— 00 
D 1527—99 

D 1693—01 
D 1785—99 
D 2235—01 
D 2241—01 
D 2282—99 
D 2412— 96a 

D 2447—99 
D 2466—01 



Specification for Pipe, Steel, Black and Hot-Dipped, Zinc-Coated Welded 

and Seamless Table 1202, 

Specification for Seamless Carbon Steel Pipe for High-Temperature Service Table 1202, 

Specification for Gray Iron Castings for Valves, Flanges, and Pipe Fittings 

Specification for Copper Brazed Steel Tubing Table 1202, 

Specification for Piping Fittings of Wrought Carbon Steel and Alloy Steel for 
Low-Temperature Service 

Specification for Electric-Resistance- Welded Coiled Steel Tubing for Gas and Fuel Oil Lines 

Specification for Solder Metal 

Specification for Seamless Copper Pipe, Standard Sizes 513.13.1, 1107.4.2, Table 1202, 

Specification for Seamless Red Brass Pipe, Standard Sizes 513.13.1, 1107.4.2, Table 1202, 

Specification for Seamless Copper Tube, Bright Annealed 

Specification for Seamless Copper Tube Table 1202. 

Specification for Seamless Copper Water Tube 513.13.1, 1107.4.3, Table 1202, 

Specification for Seamless Brass Tube Table 1202, 

Specification for General Requirements for Wrought Seamless Copper and Copper- Alloy Tube 513.13 

Specification for Seamless Copper Tube for Air Conditioning and Refrigeration 
Field Service 513.13.1, 1107.4, 

Specification for Threadless Copper Pipe, Standard Sizes Table 1202, 

Specification for Liquid and Paste Fluxes for Soldering of Copper and Copper Alloy Tube 

Specification for Clay Flue Linings 801.16.1 

Test Method for Hot-Surface Performance of High-Temperature Thermal Insulation 

Test Method for Flash Point by Tag Closed Tester 

Test Method for Flash Point of Pensky-Martens Closed Cup Tester 

Specification for Acrylonitrile-Butadiene-Styrene (ABS) Plastic Pipe, 

Schedules 40 and 80 

Test Method for Environmental Stress-Cracking of Ethylene Plastics 

Specification for Poly (Vinyl Chloride)(PVC) Plastic Pipe, Schedules 40, 80 and 120 

Specifications for Solvent Cement for Acrylonitrile-Butadiene-Styrene (ABS) Plastic Pipe and Fittings 

Specification for Poly (Vinyl Chloride)(PVC) Pressure-Rated Pipe (SDR-Series) 

Specification for Acrylonitrile-Butadiene-Styrene (ABS) Plastic Pipe (SDR-PR) 

Test Method for Determination of External Loading Characteristics of Plastic Pipe by 

Parallel-Plate Loading 

Specification for Polyethylene (PE) Plastic Pipe, Schedules 40 and 80, Based on Outside Diameter 

Specification for Poly (Vinyl Chloride)(PVC) Plastic Pipe Fittings, Schedule 40 



,4, Table 1302.3 
,4, Table 1302.3 
. . Table 1202.5 
.4, Table 1302.3 

. . Table 1202.5 
. . Table 1302.3 

1203.3.3 

.4, Table 1302.3 
.4, Table 1302.3 

513.13.1 

.4, Table 1302.3 
.4, Table 1302.3 
.4, Table 1302.3 
.1, Table 1202.4 

.3, Table 1302.3 
.4, Table 1302.3 

1203.3.3 

, Table 803.10.4 

604.3 

202 

202 



. Table 1202.4 
. Table 1202.4 
. Table 1202.4 
. . . . 1203.3.4 
. Table 1202.4 
. Table 1202.4 



603.8.3 

.Table 1202.4 
.Table 1202.5 



102 



2003 INTERNATIONAL MECHANICAL CODE® 



REFERENCED STANDARDS 



• 



D 2467—01 
D 2468— 96a 
D 2513-^0 
D 2564— 96a 
D 2683—98 

D 2837— 98a 

D 2846/D 2846M— 99 

D 2996—00 
D 3035—01 
D 3278— 96el 
D 3309— 96a 
D 3350—01 
E84— 01 

E119— OOe 
E 136— 99e01 
E 814— 00 
F 438— 01 

F 439— 01 

F441/F441M— 99 

F442/F442M— 99 
F 493— 97 

F 876— 01 
F 877—01 

F 1055—98 

F 1281—01 

F 1974— OOe 



ASTM— continued 

Specification for Poly (Vinyl Chloride)(PVC) Plastic Pipe Fittings, Schedule 80 Table 1202.5 

Specification for Acrylonitrile-Butadiene-Styrene (ABS) Plastic Pipe Fittings, Schedule 40 Table 1202.5 

Specification for Thermoplastic Gas Pressure Pipe, Tubing, and Fittings Table 1202.4, 1203.15.3 

Specification for Solvent Cements for Poly (Vinyl Chloride) (PVC) Plastic Piping Systems 1203.3.4 

Specification for Socket-Type Polyethylene Fittings for Outside Diameter-Controlled 

Polyethylene Pipe and Tubing Table 1202.4, 1203.15.1 

Test Method for Obtaining Hydrostatic Design Basis JFor Thermoplastic Pipe Materials Table 1202.4 

Specification for Chlorinated Poly (Vinyl Chloride) (CPVC) Plastic Hot and Cold Water 

Distribution Systems Table 1202.4, 1203.3.4 

Specification for Filament- Wound Fiberglass (Glass Fiber Reinforced Thermosetting Resin) Pipe Table 1302.3 

Specification for Polyethylene (PE) Plastic Pipe (DR-PR) Based on Controlled Outside Diameter Table 1202.4 

Test Methods for Flash Point of Liquids by Small Scale Closed-Cup Apparatus 202 

Specification for Polybutylene (PB) Plastic Hot- and Cold- Water Distribution Systems Table 1202.4, 1203.10.1 

Specification for Polyethylene Plastics Pipe and Fittings Materials Table 1202.4 

Test Method for Surface Burning Characteristics of Building Materials 202, 510.8, 602.2.1, 602.2.1.5, 

604.3, 1204.1 

Test Method for Fire Tests of Building Construction and Materials 607.5.2, 607.6.2 

Test Method for Behavior of Materials in a Vertical Tube Furnace at 750°C 202 

Test Method for Fire Tests of Through-Penetration Fire Stops 506.3.10 

Specification for Socket Type Chlorinated Poly (Vinyl Chloride) (CPVC) Plastic Pipe 

Fittings, Schedule 40 Table 1202.5 

Specification for Socket Type Chlorinated Poly (Vinyl Chloride) (CPVC) Plastic Pipe 

Fittings, Schedule 80 Table 1202.5 

Specification for Chlorinated Poly (Vinyl Chloride) (CPVC) Plastic Pipe, 

Schedules 40 and 80 Table 1202.4 

Specification for Chlorinated Poly (Vinyl Chloride) (CPVC) Plastic Pipe (SDR-PR) Table 1202.4 

Specification for Solvent Cements for Chlorinated Poly (Vinyl Chloride) (CPVC) Plastic 

Pipe and Fittings 1203.3.4 

Specification for Crosslinked Polyethylene (PEX) Tubing Table 1202.4 

Specification for Crosslinked Polyethylene (PEX) Plastic Hot and Cold- Water 

Distribution Systems Table 1202.4, Table 1202.5 

Specification for Electrofusion Type Polyethylene Fittings for Outside Diameter 

Controlled Polyethylene Pipe and Tubing Table 1202.4, 1203.15.2 

Specification for Crosslinked Polyethylene/Aluminum/Crosslinked Polyethylene 

(PEX-AL-PEX) Pressure Pipe Table 1202.4 

Standard Specification for Metal Insert Fittings for Polyethylene/ Aluminum/Polyethylene 

and Crosslinked Polyethylene/Aluminum/Crosslinked Polyethylene Composite Pressure Pipe Table 1202.5 



AWS 



American Welding Society 
550 N.WLeJeune Road 
P.O. Box 351040 
Miami, FL 33135 



Standard 

Reference 

Number 



Title 



Referenced 

in code 

section number 



A5.8— 92 



Specifications for Filler Metals for Brazing and Braze Welding 1203.3.1, 1303.3.1 



CSA 



Canadian Standards Association 

178 Rexdale Blvd. 

Rexdale (Toronto), Ontario, Canada M9W 1R3 



Standard 

Reference 

Number 



Titie 



Referenced 

in code 

section number 



CAN/CSA B137.10M— 99 Crosslinked Polyethylene/Aluminum/Polyethylene Composite Pressure Pipe Systems Table 1202.4 



2003 INTERNATIONAL MECHANICAL CODE® 



103 



REFERENCED STANDARDS 



DOL 



Department of Labor 

Occupational Safety and Health Administration 

c/o Superintendent of Documents 

US Government Printing Office 

Washington, DC 20402-9325 



Standard 
Reference 

Number 



Title 



Referenced 

in code 

section number 



29 CFR Part 1910.1000 (1974) Air Contaminants 502.6 



FS 



Federal Specifications* 
General Services Administration 
7th & D Streets 

Specification Section, Room 6039 
Washington, DC 20407 



Standard 

Reference 

Number 



Title 



Referenced 

in code 

section number 



WW-P-325B (1976) 



Pipe, Bends, Traps, Caps and Plugs; Lead (for Industrial Pressure and Soil 
and Waste Applications 



. Table 1202.4 



* Standards are available from the Supt. of Documents, U.S. Government Printing Office, Washington, DC 20402-9325. 



ICC 



Standard 




Referenced 


Reference 




in code 


Number 


Title 


section number 



IBC— 03 



ICC EC— 03 
IEBC—03 
lECC— 03 
IPC— 03 



IFGC— 03 
IPC— 03 

IRC— 03 



International Code Council 
5203 Leesburg Pike, Suite 708 
Falls Church, VA 22041-3401 

Title 

International Building Code® 201.3, 202, 301.12, 301.12, 301.14, 301.15, 

302.1,302.2,304.7,304.10, 

308.8, 308.10, 401.4, 401.6, 406.1, 502.10, 502.10.1, 504.2, 

506.3.3, 506.3.10, 506.3.12.2, 506.4.1, 509.1, 510.6, 510.6.1, 510.6.2, 510.7, 51 1.1.5, 

513.1, 513.2, 513.3, 513.4.3, 513.5, 513.5.2, 513.5.2.1, 513.6.2, 

513.10.5, 513.12, 513.12.2, 513.20, 602.2.1.5.1, 602.2.1.5.2, 602.3, 603.1, 603.10, 

604.5.4, 607.1.1, 607.3.2.1, 607.5.1, 607.5.2, 607.5.3, 607.5.4, 607.5.4.1, 

607.5.5, 607.5.5.1, 607.6, 607.6.2, 701.4.1, 701.4.2, 801.3, 801.16.1, 801.18.4, 

902.1, 908.3, 908.4, 910.3, 925.1, 1004.6, 1105.1, 

1206.4, 1402.4, 1402.4.1 

ICC Electrical Code™ 201.3, 301.7, 306.3.1, 306.4.1, 513.11, 513.12.1, 602.2.1.1 

International Existing Building CodeCg) 101.2 

International Energy Conservation Code® 202, 301.2, 303.3, 312.1, 603.9, 604.1, 1204.1, 1204.2 

International Fire Code® 201.3, 310.1, 311.1, 502.5, 502.7.2, 502.8.1, 502.9.5, 502.9.5.2, 

502.9.5.3, 502.9.8.2, 502.9.8.3, 502.9.8.5, 502.9.8.6, 502.10, 502.10.3, 

502.16.2, 509.1, 510.2.1, 510.2.2, 510.4 

513.12.3, 513.15, 513.16, 513.17, 513.18, 513.19, 513.20.2, 

513.20.3,606.2.1,908.7, 1101.9, 1105.3, 1106.5, 1106.6, 1301.1, 1301.2 

International Fuel Gas Code® 101.2, 201.3, 301.3, 701.1, 801.1, 901.1, 906.1, 1101.5 

International Plumbing Code® 201.3, 301.8, 512.2, 908.5, 1002.1, 1002.2, 

1002.3, 1005.2, 1006.6, 1008.2, 1009.3, 1101.4, 1201.1, 1206.2, 1206.3, 1401.2 

International Residential Code® 101.2 



IIAR 



International Institute of Ammonia Refrigeration 

Suite 700 

1101 Connecticut Ave., NW 

Washington, DC 20036 



Standard 

Reference 

Number 



Title 



. Referenced 

in code 

section number 



2—99 



Equipment, Design, and Installation of Ammonia Mechanical Refrigerating Systems 1101.6 



104 



2003 INTERNATIONAL MECHANICAL CODE® 



REFERENCED STANDARDS 



MSS 



Manufacturers Standardization Society of the Valve & Fittings Industry, Inc. 
127 Park Street, N.E. 
Vienna, VA 22180 



Standard 

Reference 
Number 



Title 



Referenced 

in code 

section number 



SP-69— 1996 



Pipe Hangers and Supports — Selection and Application 305.4 



NAIMA 



North American Insulation Manufacturers Association 

Suite 310 

44 Canal Center Plaza 

Alexandria, VA 22314 



Standard 

Reference 

Number 



Title 



Referenced 

in code 

section number 



AH116— 02 



Fibrous Glass Duct Construction Standards 603.5, 603.9 



NFPA 



Standard 




Referenced 


Reference 




in code 


Number 


Title 


section number 



31—01 

37—98 

58—01 

69—97 

72—99 

82—99 

88B— 97 

91—99 

211--00 
262—99 

704—96 

853—00 

8501—97 

8502—99 

8504—96 



National Fire Protection Association 
Batterymarch Park 
Quincy, MA 02269 

Title 

Installation of Oil-Burning Equipment 801.2.1, 801.18.1, 801.18.2, 920.2, 922.1, 1308.1 

Stationary Combustion Engines and Gas Turbines 915.1, 915.2 

Liquefied Petroleum Gas Code 502.9.10 

Explosion Prevention Systems 5 10.8.3 

National Fire Alarm Code 606.3 

Incinerators and Waste and Linen Handling Systems and Equipment 601.1 

Repair Garages 304.5 

Exhaust Systems for Air Conveying of Vapors, Gases, Mists, and 

Noncombustible Particulate Solids 502.9.5. 1, 502.17 

Chimneys, Fireplaces, Vents, and Solid Fuel-Burning Appliances 806. 1 

Standard Method of Test for Flame Travel and Smoke of Wires and Cables for 

Use in Air-Handling Spaces 602.2. 1 . 1 

Identification of the Hazards of Materials for Emergency Response 502.8.4, Table 1103.1, 510.1 

Installatin of Stationary Fuel Power Plants 924. 1 

Single Burner Boiler Operation 1004. 1 

Prevention of Furnace Explosions/Implosions in Multiple Burner Boiler-Furnaces 1004.1 

Atmospheric Fluidized-Bed Boiler Operation 1004. 1 



SMACNA 



Sheet Metal & Air Conditioning Contractors National Assoc, Inc. 
4021 Fafayette Center Road 
Chantilly, VA 22021 



Standard 

Reference 

Number 



Tide 



Referenced 

in code 

section number 



SMACNA— 95 

SMACNA— 92 



HVAC Duct Construction Standards — Metal and Flexible 
Fibrous Glass Duct Construction Standards 



. 603.4, 603.9 
.603.5,603.9 



2003 INTERNATIONAL MECHANICAL CODE® 



105 



REFERENCED STANDARDS 



UL 



Standard 




Referenced 


Reference 




in code 


Number 


Title 


section number 



17—94 

103—98 

127—96 
174—98 
181—96 

197—93 
207—93 

343—97 
391—95 

412—93 

471—95 

536—97 

555—99 

555C— 96 

555S— 99 

586—96 

641—95 

710—95 

726—98 

727—94 

729—98 

730—98 

731—95 

732—95 

737—96 

762—99 

791—93 

834—98 

867—00 

896—93 

900—94 

959—01 

1240—94 

1261—96 

1453—95 

1482—98 
1777—98 
1820—97 

1887—96 

1995—98 
2043—96 

2158—97 
2162—94 



Underwriters Laboratories, Inc. 
333 Pfmgsten Road 
Northbrook, IL 60062-2096 

Title 

Vent or Chimney Connector Dampers for Oil-Fired Appliances — with Revisions 

through September 1998 803.6 

Factory-Built Chimneys, Residential Type and Building Heating Appliance — with 

Revisions through March 1999 805.2 

Factory-Built Fireplaces— with Revisions through November 1999 805.3, 903.1, 903.3 

Household Electric Storage Tank Water Heaters — with revisions through October 1999 1002.1 

Factory-made Air Ducts and Air Connectors — with Revisions through December 1998 512.2, 603.5, 603.6.1, 

603.6.2,604.13 

Commercial Electric Cooking Appliances — With Revisions Through January 2000 507.1 

Refrigerant-Containing Components and Accessories, Nonelectrical — with Revisions 

Through October 1997 1101.2 

Pumps for Oil-Burning Appliances-with revisions through December 22, 1999 1302.7 

Solid-Fuel and Combination-Fuel Central and Supplementary Furnaces — with Revisions 

Through May 1999 918.1 

Refrigeration Unit Coolers — with Revisions through November 1998 1 101.2 

Commercial Refrigerators and Freezers — with Revisions through April 1998 1 101.2 

Flexible metallic Hose - with revisions through October 2000 1302.8 

Fire Dampers - with Revisions through October, 2000 607.3 

Ceiling Dampers 607.3, 607.6.2 

Smoke Dampers — with Revisions through December 1999 607.3, 607.3.1.1 

High-Efficiency, Particulate, Air Filter Units - with revisions through april 21, 2000 605.2 

Type L Low-Temperature Venting Systems — with Revisions through April 1999 802.1 

Exhaust Hoods for Commercial Cooking Equipment-with Revisions through April 1999 507.1 

Oil-Fired Boiler Assemblies — with Revisions through January 1999 916.1, 1004.1 

Oil-Fired Centeral Furnaces — with Revisions through January 1999 918.1 

Oil-Fired Floor Furnaces — with Revisions through January 1999 910.1 

Oil-Fired Wall Furnaces — with Revisions through January 1999 909.1 

Oil-Fired Unit Heaters — with Revisions through January 1999 920.1 

Oil-Fired Storage Tank Water Heaters- With revisions through January 1999 1002.1 

Fireplace Stoves — with Revisions through January 2000 805.2, 905.1 

Outline of Investigation for Power Ventilators for Restaurant Exhaust Appliances 506.5.1 

Residential Incinerators — with Revisions through May 1998 907.1 

Heating, Water Supply and Power Boilers Electric — with Revisions Through November 1998 1004.1 

Electrostatic Air Cleaners 605.2 

Oil-Burning Stoves — with Revisions through November 1999 917.1, 922.1 

Air Filter Units - with revisions through October 1999 605.2 

Medium Heat Appliance Factory-Built Chimneys 805.5 

Electric Commercial Clothes Drying Equipment — with Revisions through October 1999 913.1 

Electric Water Heaters for Pools and Tubs - with revisions through November 25, 1998 916.1 

Electronic Booster and Commercial Storage Tank Water Heaters - with Revisions 

Through September 1998 ; ' 1002.1 

Solid-Fuel Type Room Heaters — with Revisions through January 2000 905.1 

Chimney Liners — with Revisions through July 1998 801.18.4 

Fire Test of Pneumatic Tubing for Flame and Smoke Characteristics - with Revisions 

through March 1999 602.2.1.3 

Fire Tests of Plastic Sprinkler Pipe for Visible Flame and Smoke Characteristics — 

with Revisions through June 1999 602.2.1.2 

Heating and Cooling Equipment - with Revisions through August 1999 911.1, 918.1, 918.3, 1 101.2 

Fire Test for Heat and Visible Smoke Release for Discrete Products and their 

Accessories Installed in Air-Handling Spaces- With Revisions through February 1998 602.2.1.4 

Outline of Investigation Electric Clothes Dryer — with Revisions through February 1999 913.1 

Outline of Investigation for Commercial Wood-Fired Baking Ovens — Refractory Type 917.1 



106 



2003 INTERNATIONAL MECHANICAL CODE® 



APPENDIX A 

COMBUSTION AIR OPENINGS AND 
CHIMNEY CONNECTOR PASS-THROUGHS 

Figures A-1 through A-4 are illustrations of appliances located in confined spaces. 



/■CHIMNEY OR VENT 




FIGURE A-1 
ALL AIR FROM INSIDE THE BUILDING 



NOTE: Each opening shall have a free area of not less than 1 square inch per 1 ,000 B tu per hour of the total input rating of all appli- 
ances in the enclosure and not less than 100 square inches. 
For SI: 1 square inch = 645 mm^, 1 British thermal unit per hour = 0.293 1 W. 



rCHIMNEYORVENT 



-ATTIC VENTILATION 
fEACH END OF ATTIC) 



ALTERNATE 
AtR INLET— 




CRAWLSPACE 
VENTILATION 



FIGURE A-2 
ALL AIR FROM OUTDOORS— INLET AIR FROM VENTILATED CRAWL SPACE AND OUTLET AIR TO VENTILATED ATTIC 

NOTE: The inlet and and outlet air openings shall each have a free area of not less than 1 square inch per 4,000 Btu per hour of the to- 
tal input rating of all appliances in the enclosure. 

For SI: 1 square inch = 645 mm^, 1 British thermal unit per hour = 0.293 1 W. 



2003 INTERNATIONAL MECHANICAL CODE® 



107 



APPENDIX A 



/-CHIMNEY OR VENT 



-ATTIC VENTILATION 
(EACH END OF ATTIC) 




FUFSNACE WATER 
HEATER 



INLET AIR DUCT 

(ENDS 1 FOOT ABOVE FLOOR) 



FIGURE A-3 
ALL AIR FROM OUTDOORS THROUGH VENTILATED ATTIC 



NOTE: The inlet and outlet air openings shall each have a free area of not less than 1 square inch per 4,000 Btu per hour of the total 
input rating of all appliances in the enclosure. 

For SI: 1 foot = 304.8 mm, 1 square inch - 645 mm^, 1 British thermal unit per hour = 0.2931 W. 



/■CHIMNEY OR VENT 




FIGURE A-4 
ALL AIR FROM OUTDOORS THROUGH HORIZONTAL DUCTS OR DIRECT OPENINGS 



NOTE: Each air duct opening shall have a free area of not less than 1 square inch per 2,000 Btu per hour of the total input rating of all 
appliances in the enclosure. If the appliance room is located against an outside wall and the air openings communicate directly with 
the outdoors, each opening shall have a free area of not less than 1 square inch per 4,000 Btu per hour or the total input rating of all 
appliances in the enclosure. 

For SI: 1 foot = 304.8 mm, 1 square inch = 645 mm^, 1 British thermal unit per hour = 0.2931 W. 



108 



2003 INTERNATIONAL MECHANICAL CODE® 



• 



APPENDIX A 



SYSTEM A 



FIRE-CLAY LINER 





2" MIN. CHIMNEY CLEARANCE 
TO BRICK AND COMBUSTIBLE 
MATERIALS. 

MIN. CLEARANCE: 
12" OF BRICK 

-CHIMNEY CONNECTOR 



=q ^^ FIRE-CLAY LINER 

3 1/2" THICK BRICK 
MASONRY CHIMNEY 



12" MIN. TO COMBUSTIBLES-" 



SYSTEM B 



WATER-INSOLUBLE 
REFRACTORY CEMENT 



CHIMNEY SECTION 
FLUSH WrrH INSIDE 
OF FLUE 




2" MIN. CHIMNEY CLEARANCE 
FROM MASONRY TO SHEET METAL 
SUPPORTS AND COMBUSTIBLE 
MATERIALS. 



MIN. CLEARANCE 



CHIMNEY CONNECTOR 

CHIMNEY SECTION MANUFACTURER'S 
PARTS SHAU BE UTIUZED TO ATTACH 
CONNECTOR TO CHIMNEY SECTION. 
LABELED. SOUD- INSULATED, FACTORY- 
BUILT CHIMNEY SECTION 
SHEET STEEL SUPPORTS 




FACTORY-BUILT 
CHIMNEY SECTION 



L-9" MIN. AIR SPACE 



I — MASONRY CHIMNEY 



FIGURE A-5 
CHIMNEY CONNECTOR SYSTEMS 



For SI: 1 inch = 25.4 mm. 



2003 INTERNATIONAL MECHANICAL CODE® 



109 



APPENDIX A 



SYSTEM C 



■SHEET METAL THIMBLE 
(24 GAGE MIN.) 




ui 

3 



X 
O 



TWO VE^^■|LATED AIR 
CHANNELS EACH OF 1". 



-2" MIN. CHIMNEY CLEARANCE 

TO SHEET STEEL SUPPORTS AND 

a COMBUSTIBLE MATERIALS 

>,,^GLASS-nBER INSULATION 

3 ^ TWO 1" AIR CHANNELS 
•CI 

•CHIMNEY CONNECTOR 
(24 GAGE MIN.) 



6" MIN. 



SHEET STEEL SUPPORTS 
(24 GAGE MIN.) 

MASONRY CHIMNEY 




SYSTEM D 




FACTORY-BUILT 
CHIMNEY SECTION 



CHIMNEY CONNECTOR 
(24 GAGE MIN.) 



2" AIRSPACE 
SHEET STEEL SUPPORTS 



2" MIN. CHIMNEY CLEARANCE 
TO SHEET STEEL SUPPORTS AND 
COMBUSTIBLE MATERIALS. 
2" MIN. CLEARANCE 
V ANNULAR AIRSPACE 
BETWEEN CHIMNEY CONNECTOR 
AND CHIMNEY SECTION 

CHIMNEY CONNECTOR 



FACTORY-BUILT 
CHIMNEY SECTION 

■SHECT STEEL SUPPORTS 
I — MASONRY CHIMNEY 




FIGURE A-5— continued 
CHIMNEY CONNECTOR SYSTEMS 



For SI: 1 inch = 25.4 mm. 



110 



2003 INTERNATIONAL MECHANICAL CODE® 



APPENDIX B 

RECOMMENDED PERMIT FEE SCHEDULE 



B101 
MECHANICAL WORK, OTHER THAN GAS PIPING SYSTEMS 

BlOl.l Initial Fee 

For issuing each permit $ 

B101.2 Additional Fees 
BlOl.2.1 Fee for inspecting heating, ventilating, ductwork, air-conditioning, exhaust, venting, combustion air, pressure vessel, 
solar, fuel oil and refrigeration systems and appliance installations shall be $ for the first $1,000.00, or fraction thereof, of val- 
uation of the installation plus $ for each additional $1,000.00 or fraction thereof. 

BlOl.2.2 Fee for inspecting repairs, alterations and additions to an existing system shall be $ plus $ for each $ 1 ,000.00 or 

fraction thereof. 

BlOl.2.3 Fee for inspecting boilers (based upon Btu input): 

33,000 Btu (1 BHp) to 165,000 (5 BHp) $ 

165,001 Btu (5 BHp) to 330,000 (10 BHp) $ 

330,001 Btu (10 BHp) to 1,165,000 (52 BHp) $ 

1,165,001 Btu (52 BHp) to 3,300,000 (98 BHp) $ 

over 3,300,000 Btu (98 BHp) $ 

For SI: 1 British thermal unit = 0.2931 W, 1 BHp = 33,475 Btu/hr. 

B102 
FEE FOR REINSPECTION 

If it becomes necessary to make a reinspection of a heating, ventilation, air-conditioning or refrigeration system, or boiler installation, 
the installer of such equipment shall pay a reinspection fee of $ . 

B103 
TEMPORARY OPERATION INSPECTION FEE 

When preliminary inspection is requested for purposes of permitting temporary operation of a heating, ventilating, refrigeration, or 

air-conditioning system, or portion thereof, a fee of $ shall be paid by the contractor requesting such preliminary inspection. If 

the system is not approved for temporary operation on the first preliminary inspection, the usual reinspection fee shall be charged for 
each subsequent preliminary inspection for such purpose. 

B104 
SELF-CONTAINED UNITS LESS THAN 2 TONS 

In all buildings, except one- and two-family dwellings, where self-contained air-conditioning units of less than 2 tons are to be in- 
stalled, the fee charged shall be that for the total cost, of all units combined (see B 101. 2.1 for rate). 



2003 INTERNATIONAL MECHANICAL CODE® 1 1 "> 



112 2003 INTERNATIONAL MECHANICAL CODE® 



INDEX 



• 



A 

ADMINISTRATION AND 

ENFORCEMENT Chapter 1 

AIR 

Combustion Chapter 7 

Distribution systems Chapter 6 

Filters 605 

Transfer 403.2.2 

Supply Chapter 4 

Ventilation Chapter 4 

ALTERNATIVE MATERIAL 105.2 

APPEAL 109 

APPLIANCES 

Access .306 

Hazardous location 303.2 

Installation Chapters 3, 9 

Outdoors 303.6 

APPLICABILITY OF CODE 102 

APPROVAL 105 

ATTIC VENTILATION 406 

AUTOMATIC DAMPERS 803.6 

AUTOMATIC FIRE SUPPRESSION, 
KITCHEN EXHAUST 509 

B 

BARBECUE APPLIANCES 906 

BATHROOM VENTILATION 402, 403 

BLOWOFF VALVE, STEAM 1008 

BOILERS 

Approval 1004.1 

Controls 1006 

Gauges 1010 

General 1001 

Low-water cutoff 1 007 

Rooms 1004.6 

BURNER, CONVERSION 919 

c 

CANOPY HOODS 507.12, 507.13 

CEILING DAMPERS 607 

CHILLED WATER PIPING Chapter 12 

CHIMNEYS AND VENTS 

Connectors 803 

Dampers 803.5, 803.6 

Direct Vents 804.1 

Exhausters 804.3 

Existing 801.18 

Factory built 802, 805 

General 801 

Masonry, general 801 

Vents 802 



CLEANOUTS 

Kitchen exhaust 506.3.9, 506.3.10 

Masonry chimneys 801 .13 

CLEARANCES 

Appliance in garages 304.5, 304.6 

Chimney and vent 801.18.4 

Connectors 803.10.6 

Kitchen exhaust 506.3.6, 507.9 

Reduction 308 

Specific appliances Chapter 9 

CLOTHES DRYER 

Appliance 913 

Exhaust 504 

COAL-BURNING APPLIANCES Chapter 9 

CODE OFFICIAL 103, 104, 202 

COLLECTORS, SOLAR 1402.4, 1404.1 

COMBUSTIBLE LIQUID STORAGE TANK 1301 

COMBUSTIBLES, REDUCED CLEARANCE 308 

COMBUSTION AIR Chapter 7 

COMMERCIAL KITCHEN EXHAUST 506 

Hoods 507 

CONDENSATE DISPOSAL 307 

CONDENSATION 

Ducts 603.12 

Piping 1107.3 

CONNECTORS, CHIMNEY OR VENT 803 

CONTAMINANTS, VENTILATION AIR 401 

CONVEYOR SYSTEMS 511 

COOKING APPLIANCES 917 

COOLING TOWERS 908 

COOLING WATER PIPING Chapter 12 

COVERING, DUCT 604.3 

CRAWL SPACE PLENUMS 602 

CRAWL SPACE, VENTILATION 406 

CREMATORIES 907 

CUTTING, NOTCHING, BORING 302 



DAMPERS 

Chimney or vent 803.5, 803.6 

Combustion air 709 

Fire 607 

DEFINITIONS Chapter2 

DETECTORS, DUCT 606 

DRYER, CLOTHES 

Exhaust 504 

General 913 

DUCT 

Combustion air 708 

Construction 603 

Covering 604.3 



2003 INTERNATIONAL MECHANICAL CODE® 



113 



INDEX 



Detectors, smoke 606 

Enclosure 506.3.10, 510.4 

Exhaust 501 .4 

Fire damper 607 

Flexible 1 603.6 

Furnace 918 

Hangers and supports 603.10 

Hazardous exhaust 510 

Installation 603 

Insulation 604 

Joints 603.9 

Kitchen exhaust 506 

Lining 604.3 

Plastic 603.8.3 

Sizing 603.2 

Smoke damper 607 

Systems Chapter 6 

Underground 603.8 

DUST, STOCK AND REFUSE 
CONVEYOR SYSTEMS 51 1 

E 

ELECTRIC INSTALLATION 301 .7 

ENERGY EFFICIENCY 301.2 

ENERGY RECOVERY SYSTEMS 514 

ENGINE/TURBINE EQUIPMENT 915 

EQUIPMENT ACCESS 306 

EQUIPMENT IDENTIFICATION 304.1 1 

EXHAUST, REQUIRED SYSTEMS 502 

Clothes dryer 504 

Discharge 501 .2 

Ducts 501 .4 

Kitchen ; 505, 506, 507 

Machinery room 1 1 05, 1 1 06 

Mechanical 403, Chapter 5 

Openings 401 .5, 401 .6 

System, hazardous 510 

EXHAUSTER 804 

EXISTING SYSTEMS 102.2 

EXPLOSION VENTING 310 

F 

FACTORY BUILT 

Barbecue appliance 906 

Chimneys 805 

Commercial exhaust hoods 507.1 

Ducts (kitchen exhaust) 506.3.2, 506.3.6 

Fireplaces 903 

FANS, EXHAUST 503, 506.5.1 

FILTERS, AIR 605 

FILTERS, GREASE 507.1 1 

FIRE DAMPERS 607 

FIRE SUPPRESSION 

Hazardous exhaust 510.7 



Kitchen exhaust 509 

FIREPLACES 

Factory built 903 

Masonry 902.1 

FIREPLACE STOVE 905 

FLEXIBLE CONNECTORS (DUCT) 603.6 

FLEXIBLE CONNECTORS, HYDRONIC 1202.7 

FLEXIBLE DUCTS 603.6 

FLOOD HAZARD .... 301.13, 401.5.3, 602.4, 603.13 

FLOOR FURNACE 910 

FLUE LINERS 801.16, 801.18.2 

FUEL CELLS 924 

FUEL, CONVERSION 301.9 

FUEL OIL 

Piping Chapter 13 

Piping installation 1305 

Piping material 1 302 

FURNACE 918 

FURNACE ROOM 304.7 



GAUGES, BOILERS 1010 

GREASE 506, 507 

GREASE FILTERS 507.11 

GUARDS. 304.10 

H 

HANGERS, PIPE 305 

HAZARDOUS EXHAUST SYSTEM 510 

HAZARDOUS LOCATION, 

EQUIPMENT 304.3, 901.3 

HAZARDOUS LOCATION, INSTALLATION .... 304.3 

HEATER Chapter 9 

HEAT PUMP 918.3 

HOOD DESIGN (KITCHEN) 507 

HOOD, EXHAUST 505, 506, 507, 510.5.3 

HOT WATER BOILERS Chapter 10 

HOT WATER PIPING Chapter 12 

HYDROGEN GENERATION 

AND REFUEING 304.4 

HYDRONIC PIPING Chapter 12 

I 

INCINERATORS 907 

INSIDE AIR, COMBUSTION Chapter 7 

INSPECTION 107 

INSULATION 

Duct 604 

Pipe 1204 



114 



2003 INTERNATIONAL MECHANICAL CODE® 



INDEX 



JOINTS 

Connectors 803.10.1 

Duct 506.3.2, 510.8.1, 603.9 

Piping 1003.2, 1107.5, 1203, 1303 

K 

KEROSENE STOVE 922 

KILNS 923 

KITCHEN EXHAUST EQUIPMENT Chapter 5 



LABELING 

Criteria for 301.4, 301.5, 301.6 

LINER, FLUE 801 .16 

LINING, DUCT 604.3 

LISTING 301.4 

LOAD CALCULATIONS 312 

LOCATION, EQUIPMENT AND APPLIANCE 303 

LOW-WATER CUTOFF, BOILER 1007 

M 

MACHINERY ROOMS 1105, 1106 

MAINTENANCE 102.3 

MAKEUP AIR, EXHAUST 508, 510.5.5 

MAKEUP WATER 908.5, 1005.2, 1206.3, 1207.2 

MASONRY CHIMNEYS Chapter 8 

MASONRY FIREPLACE 902 

MECHANICAL EXHAUST/DRAFT 804 

MECHANICAL OFFICIAL (see CODE OFFICIAL) 

MECHANICAL REFRIGERATION Chapter 11 

MECHANICAL VENTILATION 304.4.2, 403 

MOTORS 503, 506.5.1.1 

MOVED STRUCTURE 102.7 

N 

NATURAL VENTILATION 304.4.1 , 402 

NONCANOPY HOODS 507.14 



OIL, FUEL PIPING Chapter 13 

OPENINGS 

Connbustion air Chapter 7 

Outside 401.5, 401.6 

OUTDOOR AIR, COMBUSTION Chapter 7 

OUTDOOR INSTALLATION 303.6 

OUTSIDE AIR, MINIMUM 403 



P 

PELLET FUEL-BURNING APPLIANCES 904 

PENETRATIONS 302.2, 607 

PERMITS 106 

PIPE 

Insulation 1107.3, 1204 

Support 305 

PIPING 

Fuel oil Chapter 1 3 

Material, fuel oil 1302 

Material, hydronic 1202 

Refrigerant 1 107 

Support 305 

PLENUMS 602 

PLUMBING 301.8 

POOL/SPA HEATER 916 

POWER EXHAUSTER 804 

PRESSURE GAUGE 1010 

PRESSURE VESSEL 1003 

R 

RADIANT HEATER 912 

RANGE HOODS Chapter 5 

REDUCED, CLEARANCE 308 

REFRIGERANT PIPING 1107 

REFRIGERANT, QUANTITY 1104 

REFRIGERATION, MECHANICAL Chapter 1 1 

REGISTERS 603.17 

RELIEF VALVES, FUEL OIL 1307 

RELIEF VALVES, PRESSURE VESSELS 1006 

RELIEF VALVES, SOLAR 1402.5.1 

REPAIRS 102.4 

ROOM HEATERS, SOLID FUEL 904, 905, 921 

s 

SAFETY VALVE 1006 

SAUNA HEATER 914 

SCOPE OF CODE 101 .2 

SEISMIC 301.15 

SIGHT GLASS 1010 

SMOKE CONTROL 513 

SMOKE DAMPERS 607 

SMOKE DETECTORS 606 

SMOKE AND HEAT VENTS 311 

SOLAR Chapter 14 

SOLID FUEL-BURNING APPLIANCES .... Chapter 9 

STANDARDS, REFERENCED 102.8, Chapter 15 

STEAM 

Blowoff 1008 

Boilers Chapter 10 



2003 INTERNATIONAL MECHANICAL CODE® 



115 



INDEX 



Gauge 1010 

Piping Chapters 10, 12 

SUBSLAB SOIL EXHAUST SYSTEM 512 

SUPPORTS, DUCT 603.10 

SUPPORTS, PIPING 305 

SUPPRESSION 

Hazardous exhaust 510.7 

Kitchen exhaust 509 

T • 

TANKS, EXPANSION 1009, 1402.5.4 

TANKS, FLAMMABLE AND 

COMBUSTIBLE LIQUIDS Chapter 13 

TEMPERATURE GAUGE 1010 

TEMPERATURE CONTROL 309.1 

TEMPERATURE RELIEF, SOLAR 1402.4 

TESTS, 

Boiler/Pressure Vessel 101 1 

Fuel Oil Piping 1308 

Hydronic piping 1208, 1209.2 

Kitchen exhaust 507.16, 507.17 

Refrigeration 1 108, 1 109 

THERMAL STORAGE, SOLAR 1404.2 

TOILET ROOM VENTILATION .... 402.1 , Table 403.3 
TRANSFER FLUID 

Hydronic piping 1207 

Solar 1403 

U 

UNDERGROUND STORAGE TANKS Chapter 13 

UNIT HEATER 920 

UNSAFE CONDITIONS 108.7 

UNVENTED GAS LOG HEATERS 903.3 

V 

VALVES 

Boilers 1005, 1008 

Fuel oil 1307 

Hydronic 1205 

Safety and relief 1006 

Stop 1107.7 

VAPOR RETARDER 604.1 1 

VENTILATION 

Air Chapter 4 

Energy Recovery Systems 514 

Machinery room 1105, 1106 

Mechanical 304.4.2, 403 

Natural 304.4.1, 402 

Openings 401 .5, 401 .6 

Rate 403.3 

Recirculation 403.2.1 

Transfer 403.2.2 

Uninhabited spaces 406 

VENTS 



Connectors 803 

Direct 804 

Explosion 310 

General 802, Chapter 8 

Smoke and Heat 31 1 

Termination 802 

VIBRATION CONTROL DEVICES 301.10 

W 

WALL FURNACE 909 

WATER HEATERS 1002 

WATER PIPING Chapter 12 

WIND RESISTANCE 301.12 

WOOD-BURNING APPLIANCES Chapter 9 



116 



2003 INTERNATIONAL MECHANICAL CODE® 



EDITORIAL CHANGES - SECOND PRINTING 

Page 22, 304.5: line 2 now reads . . . motor fuel-dispensing facilities, repair garages or other areas 

X 
Page 28, 403.3.2: Equation 4-1 now reads . . . 7 = 7 r 

(i+x-z) 

Page 39, 506.3.1.2: line 4 now reads . . . with Sections 603.1, 603.3, 603.4, 603.9, 603.10 and 603.12. 
Page 59, 607.5.4: line 4 now reads . . . barrier wall or a corridor enclosure required to have smoke 

EDITORIAL CHANGES -THIRD PRINTING 

Page 12, Added definition: ENERGY RECOVERY VENTILATION SYSTEM. Systems that employ air-to-air heat exchangers to 
recover energy from or reject energy to exhaust air for the purpose of pre-heating, pre-cooling, humidifying or dehumidifying out- 
door ventilation air prior to supplying such air to a space, either directly or as part of an HVAC system. 

Page 29, TABLE 403.3 — continued: row 2, column 3, line 8 now reads . . . intermittent 

Page 31, 501.2: Add arrow above section 

Page 32, 502.7.3.2, Exception 1.2: now reads . . . of the lower flammable limit 

Page 44, 509.1, now reads . . . Commercial cooking appliances 

Page 60, 607.6.2, Added sentence . . . Ceiling radiation dampers shall not be required where exhaust duct penetrations are protected 
in accordance with Section 712.4.2 of the /m^ma^n^5i«MrtgCaig and the exhaust ducts are located with^ 
through another dwelling unit or tenant space. 

EDITORIAL CHANGES -FOURTH PRINTING 

Page 28, 402.3: New exception following this section reads: Exception: Exterior openings required for ventilation shall be permit- 
ted to open into a thermally isolated sunroom addition or patio cover, provided that the openable area between the sunroom addition 
or patio cover and the interior room shall have an area of not less than 8 percent of the floor area of the interior room or space, but not 
less than 20 square feet ( 1 .86 m^). The minimum openable area to the outdoors shall be based on the total floor area being ventilated. 

Page 29, TABLE 403.3: row 2, column 1, line 4 now reads . . . with plumbing fixtures^s 

Page 30, TABLE 403.3— continued: row 5, column 1, line 2 now reads . . . Automotive motor-fuel-dispensing stations 

Page 48, [B]5 13.5.1: line 3 now reads . . . allowableleakagearearatio,plustheareaof other openings such as gaps and operable win- 
dows . . . 

Page 55, 603.14: last line now reads . . . with Section 603.8. 

Page 96, 1303.3.4: line 2 now reads ... by an approved procedure. The joint shall be welded with an . . . 



2003 INTERNATIONAL MECHANICAL CODE® 117 



1 1 8 2003 INTERNATIONAL MECHANICAL CODE® 



ERRATA TO THE 
2003 INTERNATIONAL MECHANICAL CODE 

Errata to the First Printing, February 2003 

(Updated October 8, 2003) 



304.5: line 2 now reads . . . motor fuel-dispensing facilities, repair garages or other areas 
403.3.2: Equation 4-1 now reads . . . 

(1 + X-Z) 

506.3.1.2: line 4 now reads . . . with Sections 603.1, 603.3,603.4, 603.9, 603.10 and 603.12. 
607.5.4: line 4 now reads . . . barrier wall or a corridor enclosure required to have smoke