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Full text of "The orientation of buildings : or, Planning for sunlight"

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The 



(Jrientation of iDuildings 



or 



Planning for Sunlight 



by 
IVilliam Atkinson 

Fellow of the Boston Society of Architects 



FIRST EDITION 
First Thousatid 



NEW YORK 

JOHN WILEY & SONS 

London : CHAPMAN ©•> HALL, Limited 
IQL2 






. Copyright, 191 2, 

BY 

WILLIAM ATKINSON 



Entered at Stationers' Hall, London 



Stanbopc lPreas 

F, H. GILSOH COMPANY 
BOSTON, U.S.A. 



In Memory of 
J. Truman Burdick 



Digitized by the Internet Archive 

in 2010 with funding from 

Open Knowledge Commons 



http://www.archive.org/details/orientationofbuiOOatki 



PREFACE 



The purpose of this book is to set forth the principles 
which ought to govern the planning of buildings with re- 
spect to sunlight, a subject to which very little attention 
has been given. 

Several years ago, in an essay on hospital construction, 1 
I wrote as follows: "To study properly the question of 
sunlight, a sun plan of the buildings must be drawn, and 
their positions considered with respect to the shadows they 
cast upon each other and upon the ground." This state- 
ment describes very well the general method of study which 
I have followed in my investigations, the results of which 
are now for the first time presented to the public in a 
complete form. 

I had begun my study of orientation with hospitals espe- 
cially in mind, but I soon realized that the general principle 
of planning with reference to sunlight was of fundamental 
importance in the design of all buildings, and especially in 
the planning and laying out of cities. In this connection I 
may mention that a series of diagrams made by me, at the 
request of a committee interested in securing new legisla- 
tion regulating the height of buildings in Boston in 1904, 
was of great service in showing the effect of tall buildings 

1 "Small Hospitals," by A. Worcester, M.D., and "Suggestions for Hospital 
Architecture," by William Atkinson, Architect, New York, John Wiley & Sons, 
1894. 

v 



VI PREFACE 

in overshadowing and shutting out the sunlight from the 
streets. Another series of street diagrams, first shown at a 
lecture given by me before the Society of Arts, at the Mas- 
sachusetts Institute of Technology, has been reprinted by 
permission in a recent English book on city planning. 
Some of my earlier studies in orientation, originally pub- 
lished in the National Hospital Record, have been twice re- 
printed in The Brickbuilder magazine, and also embodied, 
by permission, in a recent American book on hospital con- 
struction. 

All of which has encouraged me to believe that a more 
complete presentation of the subject, in book form, would 
not be without interest to the public. 

In my first chapter I have included so much of the ele- 
ments of astronomy as is necessary to a clear understanding 
of the apparent motion of the sun, and the variations in 
the angles of sunlight at the different seasons. I have also 
described the method of the stereographic projection, by 
which the angles of sunlight may easily be obtained, for 
any season of the year, and for any latitude. 

The second chapter deals with the distribution of sun- 
light upon the exterior of buildings, and its admission to 
the interior, through windows. 

In this chapter I have developed the method of the 
"shadow curve" and the "area of complete shadow," an 
application of the principles of descriptive geometry to the 
recording of transitory occurrences, which, as far as I am 
aware, is new. General principles for the planning and 
placing of buildings are given as far as it has seemed 
desirable. It is, however, to be understood that, for the 



PREFACE Vll 

best results, each case must be studied as a separate prob- 
lem, with reference to local conditions, and especially with 
reference to the latitude of the place. In connection with 
the study of windows an account is given of my experi- 
ments with the "sun box," an apparatus devised by me to 
test the practical effect of different window exposures. 

My third chapter is devoted to hospitals. In it I have 
discussed the vexed question of the best orientation for 
hospital ward pavilions and have ventured to make recom- 
mendations in this regard at variance with common prac- 
tice. I have also presented a plan for a new type of hospital 
building especially designed to meet the needs of modern 
medical treatment. 

The last chapter is concerned with the distribution of 
sunlight in streets, as affected by their direction and width, 
and the height of the buildings upon them. In an appendix 
I have given in full the building law of Paris regulating the 
height of buildings and a synopsis of the regulations of 
some American cities in this matter. 

While the working out of the diagrams and the calcula- 
tion of the tables has been a matter of pure mathematics, 
admitting but one result, the conclusions to be drawn from 
them are to some extent a matter for individual judgment. 

It is therefore fitting that I should give here a statement 
of the premises on which my recommendations are based. 

I have assumed that it is desirable, in our climate, that 
all buildings in which human beings dwell or work should 
have all of their exterior walls exposed to direct sunlight 
at some time during the day throughout the year, and that 
the surfaces of streets, alleys, areas, courtyards, and other 



Vlll PREFACE 

spaces in and around buildings should also be exposed as 
much as possible to the action of direct sunlight. 

In regard to windows, I have assumed that as much direct 
sunlight as possible is desirable through them during that 
period of the year in which they are customarily kept 
closed. On the other hand, during the hot season, when 
windows may be open day and night, and the sun-purified 
air brought in from outside by natural means, I have 
assumed that direct sunlight through windows is rather to 
be avoided than sought after. 

The function of sunlight in promoting healthy condi- 
tions, and its use as a therapeutic agent, may only be 
authoritatively stated by sanitarians and medical men 
who have given special study to this question, and I can do 
no more than refer those who may wish to pursue this 
branch of the subject to the work of the German and 
Danish investigators, a full account of which may be 
found in Luft-und Sonnenbdder , by Dr. Julian Marcuse, 
Stuttgart, 1907. 

The diagrams for this book have been engraved by the 
wax process from drawings made by me, and the few which 
have appeared in former published articles have been care- 
fully revised and redrawn. 

Boxford, Mass., 
October, 191 1. 



CONTENTS 



CHAPTER I 

THE ASTRONOMICAL DATA 

Sunlight a requisite for healthy buildings. — An elementary knowledge of as- 
tronomy necessary for intelligent sun-planning. — The angles of sunlight at the 
different seasons and in different latitudes. — Calculation of the angles of sun- 
light by the stereographic projection. — By spherical trigonometry. — Table of 
sunlight angles. 

CHAPTER II 

SHADOW DIAGRAMS 

Shadows of the cube. — Orientation of the Swiss house. — Shadow curves of 
the cube. — Theory of the area of complete shadow. — The area of complete 
shadow as applied to the study of fundamental types of building plan. — Sunlight 
admitted by windows. — The visual angle of windows. — Quantity of sunlight 
admitted by windows. — Heating effect of sunlight. — The solar constant. — 
The sun box. — Sun-box records. 

CHAPTER III 

HOSPITALS 

The orientation of ward pavilions. — Different views upon the subject. — 
Recommendations of the author. — The typical ward pavilion. — Its unsuit- 
ability to modern conditions. — A new type of ward needed. — Description of the 
pyramidal type of ward. 

CHAPTER IV 

STREETS 

Angles of sunlight in streets. — Sunlight curves in streets. — The orientation of 
streets. — Horace Bushnell's theory. — ■ The height of buildings. — European 
building regulations. — The law of ancient lights. — Building law recommended 
by the author. — The skyscraper and the street. 

APPENDIX A 

Sun tables for London and New Orleans. 

APPENDIX B 

Building laws of Paris regulating the height of buildings. 

APPENDIX C 

Building laws of American cities regulating the height of buildings. 



LIST OF ILLUSTRATIONS 



CHAPTER I 

Fig. Page 

i. Cross sections of the visible celestial sphere 3 

2. Apparent orbits of the sun at the different seasons 6 

3. Paths of the sun at intermediate periods 7 

4. Stereographic projection of the visible celestial sphere 9 

5. Construction of the stereographic projection. — First step 12 

6. Construction of the stereographic projection. — Second step 14 

7. Construction of the stereographic projection. — Third step 16 

CHAPTER II 

8. Shadows of the cube 20 

9. Shadows of the cube 21 

10. Shadows of the cube 22 

11. Plan of typical Swiss dwelling 23 

12. Shadow curves of the cube. Winter solstice 25 

13. Shadow curves of the cube. Winter solstice 26 

14. Shadow curves of the cube. Equinoxes 27 

15. Shadow curves of the cube. Equinoxes 28 

16. Shadow curves of the cube. Summer solstice 29 

17. Shadow curves of the cube. Summer solstice 30 

18. Areas of complete shadow: single straight block 32 

19. Areas of complete shadow: L plan 33 

20. Areas of complete shadow: U plan 34 

21. Method of obtaining the area of complete shadow 36 

22. Shadow curves of cube and prism at winter solstice 37 

23. Maximum areas of complete shadow for the L and U plans 38 

24. Effect of increase of height upon the area of complete shadow 39 

25. Good and bad arrangement of L 41 

26. Application of the test of the area of complete shadow 42 

27. Shadows of the single straight block. Axis N. and S 44 

xi 



Xll LIST OF ILLUSTRATIONS 

Fig. Page 

28. Shadows of the single straight block. Axis E. and W 45 

29. Shadows of the single straight block. Axis N. E. and S. W 46 

30. Visual angle of ordinary window 47 

31. Visual angle of mediaeval window 48 

32. Wall section with beveled piers 49 

33. Window illumination: winter solstice 50 

34. Window illumination: equinoxes S 1 

35. Window illumination: summer solstice 52 

36. Cross sections of sunlight prism 53 

37. Change in area of sunlight prism: winter solstice 55 

38. Change in area of sunlight prism: equinoxes 56 

39. Change in area of sunlight prism: summer solstice 57 

40. Windows : obstructed outlook 59 

41. Obstructed outlook: stereographic projection 61 

42. Change in area of sunlight prism: obstructed outlook 62 

43. Cross section of sun box 64 

44. Photograph of sun box 65 

45. Sun box records 76 

46. Sun house 77 

CHAPTER III 

47. Ward pavilion: open-ended type 80 

48. French method of hanging outside blinds 84 

49. Economy of two-story type of pavilion 86 

50. Section of ward with ridge ventilation 88 

51. Types of ward pavilions 89 

52. Grouping of ward units: Virchow Hospital 91 

53. Grouping of ward units 92 

54. Grouping of ward units 93 

55. Grouping of ward units 95 

56. Elevation of Virchow ward unit 97 

57. Pyramidal type of ward construction 98 

58. Pyramidal ward unit: first-floor plan 99 

59. Pyramidal ward unit: second-floor plan 100 

60. Pyramidal ward unit: third-floor plan 101 

61. Pyramidal ward unit: shadow diagram 102 



LIST OF ILLUSTRATIONS xm 

Fig. Page 

62. Pyramidal ward unit: shadow diagram 103 

63. Pyramidal ward unit: shadow diagram 104 

64. Pyramidal ward unit: general plan 1 06 

65. Pyramidal ward unit: elevation 107 

CHAPTER IV 

66. Angles of sunlight in streets in 

67. Angles of sunlight in streets 112 

68. Angles of sunlight in streets 113 

69. Method of obtaining sunlight curves 114 

70. Sunlight curves: streets 116 

71. Building law of Paris 119 

72. Typical cornice section 122 

73. Proposed building law 123 

74. The skyscraper and the street 124 



THE ORIENTATION OF 
BUILDINGS 



CHAPTER I 

THE ASTRONOMICAL DATA 

Unquestionably one of the first requisites for a healthy 
building is abundance of sunlight. Not only the exterior 
wall surfaces of buildings, but also the surfaces of the 
ground around them, should have the direct rays of the 
sun for as long a time as possible each day. 

"Second only to air, is light and sunshine essential for 
growth and health; and it is one of Nature's most power- 
ful assistants in enabling the body to throw off those 
conditions which we call disease. Not only daylight, 
but sunlight; indeed, fresh air must be sun- warmed, sun- 
penetrated air. The sunshine of a December day has 
been recently shown to kill the spores of the anthrax 
bacillus." (Healthy Hospitals, Sir Douglas Gal ton, Oxford, 

1893). 

To secure sunlight in fullest measure requires careful and 
intelligent planning with this end in view. It is necessary 
for such a study to have at hand a table, giving the angles 
of sunlight at the different hours of the day and at the 
different seasons of the year, for the particular latitude in 
question. 



ORIENTATION OF BUILDINGS 



In this chapter I shall describe one method by which 
such a table may be prepared. 

In all of the operations of practical astronomy, as in 
the calculation of position of ships at sea, or in deter- 
minations of latitude and longitude upon land, it has 
been found best to go back to the conceptions of the 
first astronomers, who imagined the earth to be the cen- 
ter of the universe, and the celestial bodies to revolve 
around it. 

And thus has survived the ancient fiction of the " celestial 
sphere." 

Viewing the heavens on a starry night, the whole firma- 
ment seems slowly to revolve, successively bringing into 
view, above the eastern horizon, one constellation after 
another. 

If, by magic power, the sun's light could be dimmed so 
that the stars should be visible in the daytime, he would 
appear, like them, to be fixed in the celestial sphere, and 
to turn with the constellations in their uniform diurnal 
motion around the pole. 

But if we could extend our observations over a period 
of several weeks, we should observe that the sun was slowly 
changing his position among the stars, passing in the 
course of a single year through the successive constella- 
tions of the zodiac, in summer north of the celestial equator, 
in winter south. 

But this change in the apparent position of the sun is so 
slow that for any single day it may be disregarded, and 
his position for that day considered as fixed in the celestial 
sphere. 



THE ASTRONOMICAL DATA 




Z S 




s' o w' 

NEW ORLEANS 

Fig. i. — Cross sections of the visible celestial sphere, showing the path of the 
sun at the solstices, and at the equinoctial periods, for different latitudes. 



ORIENTATION OF BUILDINGS 



Fig. I shows in cross section that part of the celestial 
sphere which is above the horizon, at the latitudes respec- 
tively of London (Lat. 5i°-3o' N.), Boston (Lat. /\2°-22' N.), 
and New Orleans (Lat. 3o°-o' N.). 

In tnese diagrams H'H represents the plane of the 
horizon; the position of the observer; P the celestial 
north pole; Z the zenith,- and SS\ EO, and WW the 
apparent paths of the sun at the periods of the summer 
solstice, the equinoxes, and the winter solstice, respectively. 

It is evident that the altitude of the sun, at noon, at the 
periods of the year referred to, may be obtained directly 
from the diagrams, being given by the angles HOS, HOE, 
and HOW, for the summer solstice, the equinoxes, and the 
winter solstice,. respectively. 

It will be observed that these angles are less in the more 
northerly latitudes, and that the path of the sun inclines 
more and inore toward the horizon. 

This decrease in the altitude of the sun is accompanied 
with an increasing divergence between the extreme points 
of sunrise and sunset, so that the days in summer are 
much longer, and in winter much shorter, in the countries 
of the far north, than in those which are near the equator. 

At latitude \2°-o' N. (approximately the latitude of 
Boston, Mass.) the sun rises on the longest day of the year 
about 32I north of east and sets at an equal angle north 
of west, reaching at noon an altitude of yi°-2y r above the 
horizon. 

On the shortest day of the year he rises about 32§° south 
of east and sets at an equal angle south of west, reaching 
at noon an altitude of only 24°-33' above the horizon. 



THE ASTRONOMICAL DATA 5 

At the two periods of the year when day and night 
are of equal length he rises in the east and sets in the 
west, reaching at noon an altitude of 48°-o / above 'the 
horizon. 

The perspective diagrams of Fig. 2 will give the student 
an easily-remembered mental image of the path of the sun 
at these periods. 

The horizontal circle represents the horizon; the inclined 
circle the path of the sun, and the diverging lines the direc- 
tion of the sun's rays at the different hours of the day. 

It will be noted that at the period of the equinoxes the 
trace of the sun's rays describes a plane; at the period of 
the summer solstice a hollow cone, and at the period of 
the winter solstice a convex cone. 

His path at intermediate periods may be pictured by the 
aid of the following diagram (Fig. 3) which gives his posi- 
tion at intervals of one month apart throughout the year. 

It will be observed from this diagram that the path of 
the sun during the four months from April 21 to August 21 
resembles more nearly his path at the summer solstice 
than his path at the equinoxes, and similarly his path 
during the four months from October 21 to February 21 
more nearly his path at the winter solstice than his path 
at the equinoxes. 

This must be borne in mind in studying the various 
shadow diagrams which are given later in this book. Those 
which are drawn for the period of the winter solstice may 
be taken as typical of the four months from October 21 to 
February 21; those which are drawn from the period of 
the summer solstice of the four months from April 21 to 



ORIENTATION OF BUILDINGS 



Sunrise 



ii m t 




"Sunset 



Sunrise E 



XI HI 




W Sunset 



11 Hi 




Sunset 



Fig. 2. - Perspective diagrams showing the apparent path of he sun, «dtib 
andes of sunlight at the different hours of the day, for Lat. 42 -o N. The upper 
dLtim i^ ra for the summer solstice, the middle diagram for the vernal and 
autumnal equinox, and the lower diagram for the waiter solstice. 



THE ASTRONOMICAL DATA 



August 21 ; and those which are drawn for the period 
of the equinoxes of the two months from February 21 
to April 21, and the two months from August 21 to 
October 21. 

The position of the sun with respect to the observer is 
generally expressed in terms of azimuth and altitude. 




Fig. 3. — Cross-section of the visible celestial sphere showing the path of the 
sun at periods one month apart throughout the year. Lat. 42°-o' X. Actually 
the declination of the sun on May 21 does not exactly coincide with his declina- 
tion on July 21, although it is so represented in the diagram. A similar observation 
applies to the other dates which are grouped in pairs. The differences, however, 
are so slight that it would be difficult to represent them at the scale at which the 
drawing is made. 



The latter term requires no explanation, but the mean- 
ing of "azimuth" may not be so generally understood. 
It may preferably be explained by an example rather than 
a definition. 

Imagine a stick set upright in level ground in the sun- 
light. The deviation of the shadow cast by the stick 



ORIENTATION OF BUILDINGS 



from a true north and south direction is the azimuth of 
the sun at that moment. 

Knowing the distance of the sun north or south from 
the equator (which information may be obtained from the 
almanac) the azimuth and altitude for any particular day 
may be calculated by spherical trigonometry. 

The desired data may also be obtained very simply and 
easily, and with sufficient accuracy for our purposes, by 
the stereographic projection. 

To one who understands perspective, the stereographic 
projection presents little difficulty, as it is virtually the 
method of linear perspective applied to the representation of 
the sphere, but with this difference, that the drawing when 
completed is viewed from behind the picture plane, instead 
of in front of it, as in ordinary perspective. 

It possesses two properties which make it especially 
useful; the first being that all circles of the sphere are 
projected as circles or as straight lines, and hence may 
be drawn with compasses and ruler; 'and the second being 
that the angle made by the crossing of two circles upon 
the surface of the sphere is the same as the angle made by 
their projections. 

The statement that by the aid of the stereographic pro- 
jection one may, with a few hours' labor, construct a 
diagram which will give the position of the sun at each 
hour of the day for any period of the year desired, and for 
any latitude, should be sufficient to induce the student to 
master its principles. 

Such a diagram, drawn for latitude 42°-o' N., is shown 
in Fig. 4. 



TEE ASTRONOMICAL DATA 



This is a stereographic projection of the celestial sphere, 

taken upon the plane of the horizon, which is represented 

by the circle N, E, S, W, these letters being placed at the 

four cardinal points. 

N 



B2, 



w 



¥-\-\-\ y i-X—\ — 



Bl 



/ / 



/ / 



\A// 



-n 



FlG. 4. — Stereographic projection of the visible celestial sphere, upon the plane 

of the horizon. 

The circular arc WE is the projection of the celestial 
equator, which is the path of the sun at the period of the 
equinoxes. 

The arc of considerably greater curvature to the north 
is the projection of the tropic of Cancer, which is the path 



IO ORIENTATION OF BUILDINGS 

of the sun at the summer solstice, while the more flat- 
tened and shorter arc to the south is the projection of the 
tropic of Capricorn, which is the path of the sun at the 
winter solstice. 

The twelve circles converging toward the upper part of 
the diagram are the projections of the celestial meridians, 
or hour circles, 15 apart. 

These hour circles may be conceived of as a gigantic 
cage or framework, fixed in position, and serving as a 
system of celestial verniers, to mark the passage of the 
heavenly bodies, which are carried past them with the 
revolution of the sphere. 

The passage of the sun across the successive hour circles 
marks the hours of the day as shown by a sundial. Con- 
sequently the intersection of any hour circle with the circle 
representing the path of the sun is the stereographic pro- 
jection of the sun's position for the corresponding hour 
and period of the year. 

And from this projection the azimuth and altitude may 
readily be found. 

For instance, the dotted line OB drawn through the 
intersection of the 11-0' clock hour circle and the celestial 
equator gives the azimuth of the sun at 11 a.m. {solar 
time) at the period of the equinoxes, and the dotted line 
OB 1 drawn through the intersection of the 1-0'clock hour 
circle and the tropic of Capricorn gives the azimuth of 
the sun at 1 p.m. on December 21st, and the dotted line 
OB2 drawn through the intersection of the 6-o'clock hour 
circle and the tropic of Cancer gives the azimuth of the 
sun at 6 p.m. on June 21st. 



THE ASTRONOMICAL DATA II 



The altitude is obtained by a simple construction. For 
example, the angle EOD is the altitude of the sun at 
II A.M. at the period of the equinoxes and is found by 
measuring off on the line OE the distance OC equal to OA 
and drawing the line SC intersecting the enclosing circle 
at the point D. 

To explain more fully the construction of the diagram, 
an example will be given and worked out. 

Let it be required to find the position of the sun at 
10 a.m., solar time, April 16, Lat. 30°-o' N. 

Draw a cross section of the visible celestial sphere, as 
shown in the upper part of Fig. 5. 

HH is the horizon, the position of the observer, and 
Z the zenith. Through O draw the line POP' making 
an angle of 30°-o' with the horizon. 

P is the celestial north pole, for it is shown in astronomy 
that the altitude of the pole is equal to the latitude of the 
place. 

Draw OE at right angles to POP. 

It represents the celestial equator. 

From the point E lay off the arc ES equal to the 
declination of the sun on the date required. This we 
find from the almanac (for 19 10) to be 9°-59' for 
April 16. 

Draw SM parallel to OE. It represents the path of the 
sun above the horizon at this period. 

The projection is made upon the plane of the horizon, 
and the station point is upon the surface of the sphere 
vertically below the zenith, at N. 

Any point upon the surface of the sphere is projected 



12 



ORIENTATION OF BUILDINGS 




Fig. 5. — Construction of the stereographic projection, first step. The upper 
part of the diagram is a cross section of the celestial sphere; the lower part its pro- 
jection upon the plane of the horizon. 



THE ASTRONOMICAL DATA 1 3 

by joining it to the station point by a straight line and 
the point in which this line pierces the picture plane HH 
is the projection required. 

The enclosing circle is the horizon, which is drawn 
without change since it lies in the plane of the projection. 

The circle MS may now be projected. 

It is evident that M' and M' are the points at which 
this circle cuts the horizon, and that S' is the projection 
of the point S. 

Through these three points draw the arc of a circle. 

It is the projection required, for it is a theorem of the 
stereographic projection that all circles of the sphere are 
projected as circles or portions of circles, with the exception 
of those which pass through the station point, which are 
obviously projected as straight lines. 

An example of the latter is the meridian or 12-o'clock 
hour circle, which is projected as the straight line 
H'S'H'. 

To find the point upon the arc M'S'M' where the sun 
is at 10 a.m. it is necessary to project the io-o'clock hour 
circle. 

(For the sake of clearness the operation is shown in a 
separate diagram, Fig. 6.) 

Since all the hour circles pass through the north and 
south poles, we have at once, in the projections of the 
poles (at PP and P'P'), two points of our required projec- 
tion. 

It remains to find the center. 

The line LT, equidistant from PP and P'P', contains 
the centers of all circles passing through those points. 



14 



ORIENTATION OF BUILDINGS 






1 
1 




Is 


\ 
\ 
\ 




\ 


/ s 


\ 


S S 










"■--^r- 






FlG. 6. — Construction of the stereographic projection, second step. 



THE ASTRONOMICAL DATA 15 

To find the point upon this line which is the center of 
the projected 10-0'clock hour circle, we avail ourselves of 
the second theorem of the stereographic projection, which 
is that the angle made by two circles upon the surface 
of the sphere is the same as the angle made by their 
projections. 

Now the 10-0'clock hour circle makes an angle of 30 
with the noon circle, or meridian, where it crosses the 
latter at the poles, one hour being equal to 15 . 

Consequently a line drawn through PP, the projection 
of the north pole, and making an angle of 30 with PP P'P', 
the projection of the meridian, is a tangent to the pro- 
jection of the 10-0'clock hour circle, and establishes the 
center of the latter at once, at the point T, upon the 
line LT. 

The circle may now be drawn. 

Superposing the two circles thus obtained in one diagram 
(Fig. 7), their intersection at A is the projection of the sun's 
position and the angle H'OX is the true bearing or azimuth 
of the sun required. 

The altitude may be found by a secondary construction. 
(Lower diagram of Fig. 7.) 

It is evident that the straight line XAO is the projection 
of a circle, vertical to the plane of the horizon, and passing 
through the zenith and the sun. 

The sun's altitude is measured upon this circle, upward 
from the horizon. 

Let us imagine this circle to be revolved into the plane 
of the horizon, thus bringing the station point to the posi- 
tion N and the zenith to the position Z. 



:-' 



ORIENTATION OF BUILDINGS 





Fig. 7. — Construction of the stereographic projection, third step. (The point 
P referred to in the test is the projection of the north pole, to the left of 0, on 
the dotted line E'H'.j 



THE ASTRONOMICAL DATA 



17 



The sun lies at some point upon this circle. To find 
this point draw the line NA cutting the circle at K. It 
is the point required, and XOK is the altitude of the sun 
required. 

By following the above method and making the pro- 
jection at a large scale the angles may be found with suffi- 
cient accuracy for the purposes of the architect. 

To obtain the result by calculation involves the solution 
of the spherical triangle POA of which the two sides PA 
(the north polar distance of the sun), PO (the co-latitude 
of the place), and APO (the assumed hour angle) are 
known. (Upper diagram of Fig. 7.) 

Solving for the angle A OP and the third side AO gives 
us H'OX, and XA the azimuth and altitude respectively. 

In the following table is given the azimuth and altitude 
of the sun for 42 north latitude at each hour of the day 
for the typical periods of the year. 



TABLE I 



Hour angle. 



S-7 105 



7 -S 
It. 1 *5 



90 

75 c 

6o c 

45 C 



Winter solstice. 



Equinoxes. 



Azimuth. , Altitude. Azimuth. Altitude. 



S^ -49 
4i°-38' 

29 °- o' 

i4°-58' 

o°- o' 



4-17 

I2°-28' 

i8°-55' 
23 °- 6' 
24°"33' 



90-0 
79°-5° 
68°-53 
56°-i3 
40°-47 
2i°-49 
o°- o 



" - 5 
2i°-49' 

3i°-42' 

40°- 4' 
45°-52' 
4S - o' 



Summer solstice. 



Azimuth. Altitude. 



H7°-io' 


5°-9' 


i°7°-52' 
98°-46' 
89°-i2' 
77° _ 5S 
6'2°-47' 
38°-36' 


i5°-27' 
26°-i7' 

37°-23' 

4 S°-2 7' 

5S°-57' 
6 7 °- 3 8' 


o°- 0' 


7 i°-2 7 ' 



Sunrise and sunset. 


4 h. 28 m. 
6 h. m. 


57 — 37' o°— 0' 














90°-o' 


o°-o' 






7 h. 32 m. 






I22°-2 3 ' 


~° «' 














1 8 ORIENTATION OF BUILDINGS 

EXPLANATION OF TABLE. 

The first column gives the solar time expressed in hour angles, one hour being 
equal to 15 degrees, reckoning either way from noon. For instance, the hour angle 
30 degrees corresponds to 10 a.m. or 2 p.m., the hour angle 45 degrees to 9 a.m. 
or 3 p.m., and so on. Azimuth is east of south for the forenoon and west of south 
for the afternoon. 

No corrections have been made for refraction, the effect of which is to slightly 
increase the altitude when the sun is near the horizon. 

This table is the basis on which all of the diagrams in this 
book have been constructed. 

Similar tables, computed for the latitudes of London and 
New Orleans, will be found in the appendix. 



CHAPTER II 

Shadow Diagrams 

As the first example of the application of the data 
obtained in the preceding chapter, let us consider the 
shadows cast by two cubes, one of them placed with its 
four sides facing the cardinal points, and the other with 
its diagonal upon the meridian. 

These shadows are shown in Figs. 8, 9, and 10 and are 
given for each hour of the day at the typical periods of 
the year. 1 

It is evident that in the first position the north face of 
the cube receives no sunlight during one-half the year, 
from the autumnal to the vernal equinox, whereas in the 
second position all four faces receive sunlight at some por- 
tion of each day, throughout the year. 

There is another advantage, not inconsiderable, in the 
latter arrangement, since in this position the cube shades 
the surface of the ground considerably less than when it 
is placed squarely facing the cardinal points. 

A study of the diagrams will make this apparent. 

It will be noted that in the lower diagrams of each 
figure the shadows overlap each other to a greater extent 
than they do in the upper ones and furthermore that in 
the lower diagram of Fig. 8 there is a triangular area which 
receives no sunlight at all. 

1 These diagrams and all those which follow are drawn for latitude 42°-o' north. 

19 




Fig. 8. — Shadows of the cube, winter solstice. The shaded area in the lower 
diagram receives no sunlight. Lat. 42°-o' N. 20 



VIII IX X XI XII I II III 




VIII IX X XI XII I II III 





Fig. 9. — Shadows of the cube, autumnal and vernal equinox. Lat. 42°-o' N. 




Fig. io. — Shadows of the cube, summer solstice. Lat. 42°-o' N. 22 



SHADOW DIAGRAMS 



23 



The advantage of placing a square building with its 
diagonal upon the meridian was long ago recognized by 
the mountain dwellers of Switzerland. 

The ground plan of a typical Swiss dwelling is shown 
in Fig. n. 1 

It will be observed that the living room is placed in the 
sunniest corner of the building, with its windows facing 
southeast and southwest. 




-1 


kwlllllllll 


r 






u 







1 


oo[ 




= 






J^>\ 












J\ - 




3 

=-l 




tf— ■ 




'— J 



Fig. 11. — Ground plan of Swiss dwelling, showing the customary orientation. 
A is the Living Room. 



Referring again to the shadows of the cube it will be 
observed that at the equinoctial periods the tips of the 
shadows move in a straight line from west to east, whereas 
at all other seasons they describe a curve. 

A further study of the diagrams will show that other 
curves are contained in them besides those described by 
the tips of the shadows, and in one of the diagrams such 
a curve is shown, passing through certain points of inter- 
section of the shadows, those points having been selected 

1 Taken from Die Holz-Architectur der Schweiz. Gladbach. Zurich and 
Leipzig, 1885. 



24 



ORIENTATION OF BUILDINGS 



which are in shadow for exactly two hours, as, for instance, 
the point P, which first comes into shadow at 10 A.M., 
and emerges again at noon. And a study of the diagram 
(Fig. 8) will show that each of the other points is in 
shadow for the same length of time. 

Such a curve may be called a "shadow curve," and the 
curve of our figure the "two-hour shadow curve." In the 
same way we might draw the "three- hour" and the "four- 
hour shadow curve," and so on, until our original drawing 
should become translated into a new and strange diagram, 
consisting entirely of curves. 

, It is in this manner that the following diagrams have 
been drawn (Figs. 12 to 17). 

To express more clearly their meaning, the zones between 
the curves have been shaded in a series of tints, correspond- 
ing to the following table: 











1 
































— 












:1 
1 

■'■i 

4 



Area in sunlight between 9 and 8 hours. 
Area in sunlight between 8 and 7 hours. 
Area in sunlight between 7 and 6 hours. 
Area in sunlight between 6 and 5 hours. 
Area in sunlight between 5 and 4 hours. 
Area in sunlight between 4 and 3 hours. 
Area in sunlight between 3 and 2 hours. 
Area in sunlight between 2 and 1 hours. 
Area in sunlight for less than 1 hour. 
Area without sunlight. 



These diagrams not only illustrate, in a graphic manner, 
the effect of the object or building, in shading the ground 
around it, but they also indicate the distribution of sun- 



SHADOW DIAGRAMS 



25 




26 



ORIENTATION OF BUILDINGS 




SHADOW DIAGRAMS 



27 




28 



ORIENTATION OF BUILDINGS 




SHADOW DIAGRAMS 



29 




3Q 



ORIENTATION OF BUILDINGS 




SHADOW DIAGRAMS 31 



light upon the vertical surfaces, or walls, of the building 
itself. 

In the same manner the shadow curves of any object or 
building may be obtained. 

The process affords a useful exercise in descriptive 
geometry, and the results are interesting and instructive. 
To reproduce the complete series of shadow curves for 
each type of object or building which we shall study 
would, however, require an unduly large number of dia- 
grams. 

It becomes desirable therefore to devise a method 
which will present the subject in a more condensed 
form. 

Such a method has been adopted for the diagrams which 
follow, and the manner of their construction will now be 
explained. 

In the discussion of the shadow curves of the cube, it was 
pointed out that one of the diagrams differed essentially 
from the others in that it disclosed an area having no sun- 
light at all during the day. 

Such an area will be called an area of complete shadow 
and may be defined as follows: 

The area of complete shadow of any object reposing 
upon a horizontal plane surface is that portion of the 
object, and of the surface upon which it rests, which is 
continuously in shade at the particular period of the year 
under consideration, and an area of perpetual shadow is that 
portion of the surface which receives no direct sunlight 
at any time during the year. 

It is evident that by superposing the areas of complete 



3 2 



ORIENTATION OF BUILDINGS 



shadow for different seasons, we may, in a single diagram, 
embrace the phenomena of an entire year. 

And this has been done in the following diagrams 
(Figs. 18, 19, and 20) in which the waxing and the wan- 
ing of the area of complete shadow is shown by indicat- 
ing its size at periods one month apart • throughout the 
year. 

These diagrams show the area of complete shadow for 
the three fundamental types of building plan: the single 
straight block (of which the cube is a particular case), 

N 





Fig. 18. — Areas of complete shadow; single straight block. Lat. 42°-o' N. 

two blocks arranged as an L, and three blocks arranged 
as a U. 

As almost all buildings are composed, in their elements, 
of these simple shapes, in various combinations, it follows 
that a careful study of these diagrams will enable one to 
criticize intelligently, as far as concerns the orientation, 
the plan of almost any building. 

In the single straight block (Fig. 18) it will be seen that 
there is an area of complete shadow present in two of the 
positions shown. 

This area first appears on September 21 and increases 
in size up to December 21, after which it decreases, until 
by March 21 it has disappeared altogether. 



SHADOW DIAGRAMS 



33 



In the other two positions the absence of an area of 
complete shadow indicates that each wall of the building 
and all portions of the ground around it receive sunlight 
at some period of the day throughout the year. 




Fig. 19. — Areas of complete shadow; two blocks arranged as an L. The solid 
black represents the area of complete shadow at the summer solstice, the lightest 
tint the area of complete shadow at the winter solstice, and the intermediate tints 
the areas of complete shadow at intervals one month apart for the intervening 
periods of the year. Lat. 42°-o' N. 



In the case of the L plan (Fig. 19) there is one position 
(that in which the reentrant angle faces the north) in 
which an area of perpetual shadow first appears, and 
in the U plan. (Fig. 20) there are three such positions, 



34 



ORIENTATION OF BUILDINGS 






Fig. 20. — Areas of complete shadow; three blocks arranged as a U. 

The height of the blocks in these three diagrams (Figs. 18, 19 and 20) is taken as 
equal to their width. Lat. 42°-o' N. 



SHADOW DIAGRAMS 35 



those in which the U court faces north, northeast, and 
northwest. 

The significance of these diagrams will perhaps be better 
understood by a study of Fig. 21, which illustrates the 
method of obtaining the area of complete shadow for the 
L plan. 

In all of the foregoing diagrams the height of the blocks 
is assumed to be equal to their width. 

The effect of an increase in height will now be con- 
sidered. 

As the first example we will take the cube and compare 
its shadow diagram with that of a square prism having a 
height, let us say, equal to five times the width. We may 
imagine the one to represent a building 60 feet square and 
60 feet high, and the other a tower 60 feet square and 300 
feet high. 

The diagrams (Fig. 22) represent the shadow curves of 
the two at the winter solstice. 

It will be noted that the increase in height enlarges the 
outer series of curves but does not affect those in the 
immediate vicinity of the building, and, furthermore, that 
the area of complete shadow is the same in both cases. 
An increase of height of the single straight block produces 
a similar effect. 

In certain positions of the L and U plans, however, an 
increase of height produces an enlargement of the area 
of complete shadow up to a certain point, beyond which 
any further increase produces no further change in the 
area of complete shadow upon the ground. 

It must be remembered, however, that the presence of 



36 



ORIENTATION OF BUILDINGS 





Fig. 22. — Showing the effect of an increase of height upon the shadow curves. 
The lower diagram represents a cube, and, at a smaller scale, is identical with 
Fig. 12. The upper diagram represents a prism of a height equal to five times 
that of the cube. Winter solstice, Lat. 42°-o' N. 37 



38 



ORIENTATION OF BUILDINGS 



an area of complete shadow in plan indicates that it also 
extends over a portion of the walls of the building. 

The maximum areas of complete shadow for the L and 
U plans produced by an increase in height, are shown in 
Fig. 23, and in Fig. 24 is shown in isometric projection the 
area of complete shadow of the L plan, in that position of 
the L in which the reentrant angle faces the north. 







•s 


s* 











Fig. 23. — Showing the maximum areas of complete shadow for the L and U 
plans. The diagrams at the left represent the winter solstice; at the right, the 
summer solstice, and between the two, the vernal and autumnal equinox. Lat. 
4 2°-o' N. 



It is of course to be understood that these positions of 
the L and U plan are undesirable. 

For example, let us imagine that we are planning a 
country dwelling of the farm-house type. The main por- 
tion of the building has been correctly placed at an angle 
of 45 with the meridian and the question before us is 
the position of the L or wing, containing the kitchen 



SHADOW DIAGRAMS 



39 





Fig. 24. — Areas of complete shadow for the L plan, autumnal and vernal equi- 
nox, showing the effect of an increase of height. Lat. 42 N. ^ 



40 ORIENTATION OF BUILDINGS 

and shed (Fig. 25). Of the two arrangements shown 
in the figure the lower is to be preferred, since in the 
upper there is a reentrant angle facing the north, involv- 
ing an area of complete shadow at all seasons of the 
year. 

The presence or absence of an area of complete shadow 
is a useful criterion by which to judge of the excellence 
of any given plan, and it is a test which should 
always be applied in studying a group of buildings or 
in planning a building having a number of courts or 
wings. 

To determine the area of complete shadow at the equi- 
noctial periods is a simple matter, since at this time the 
trace of the sun's rays describes a plane, and the tips of 
the shadows of any object cast upon level ground move 
in a straight line from west to east, as we have already 
seen in the shadows of the cube. 

As an example let us apply this test to a type of plan 
which is quite a common one for institutional buildings 
(Fig. 26). 

It will be found that, in any position in which this plan 
may be placed, there is an area of complete shadow always 
present. 1 

In all the cases so far considered, it will be observed 
that the positions which give the least amount of shaded 
area are those in which the blocks or buildings are placed 
at an angle of 45 with the meridian. 

1 In making the sun plan of a building care must be taken to distinguish between 
the magnetic north and the true meridian. It is customary in surveyors' plans 
to mark the magnetic north by the symbol of a one-sided arrow, while the true 
north is denoted by a full-fledged arrow. 



SHADOW DIAGRAMS 



41 





Fig. 25. — Good and bad arrangement of L. The shaded area in the upper part 
of the figure shows the area of complete shadow at the autumnal and vernal equi- 
nox. Lat. 42°-o' N. 



42 



ORIENTATION OF BUILDINGS 



The next step in our study will be to consider the group- 
ing of buildings, such a problem, for instance, as is presented 
in planning a pavilion hospital. 

In studying groups of buildings we have not only to con- 
sider the shadows cast by the buildings upon the ground, 



^_H 



Fig. 26. — This is a common type of plan for hospitals and other institutional 
buildings. It is given here as an example to be avoided, since it involves an area 
of complete shadow in any position in which it may be placed. 



but also the shadows cast by the different buildings upon 
each other. Figs. 27, 28, and 29 represent, in isometric 
projection, two of our single straight blocks placed side 
by side, with the shadows as they would be at the winter 
solstice, when the interference of one building with another 
is the greatest. 



SHADOW DIAGRAMS 43 



In Fig. 27 the long axis of the blocks runs north and 
south; in Fig. 28 east and west, and in Fig. 29 northeast 
and southwest. 

The latter figure will also serve for the case in which 
the axis of the blocks runs northwest and southeast, the 
forenoon diagrams of the one corresponding to the after- 
noon diagrams of the other, and vice versa. 

The blocks are placed at a distance apart equal to twice 
their height, the arrangement usually recommended for the 
ward pavilions of a hospital. 

A study of these diagrams which, as above noted, repre- 
sent the most unfavorable conditions of the whole year, 
justifies the conclusion that adequate sunlight may be 
obtained with a distance between the blocks of considerably 
less than that shown. 

Such is the kind of study which the architect must 
pursue in order to become proficient in the art of sun- 
planning. 

How much weight should be given to the question of 
sunlight must be a matter for judgment in each case, but 
to wilfully create an area of complete shadow when, by some 
different arrangement of plan, it might have been avoided, 
without detriment to more important considerations, can- 
not be considered good architecture. 

Just as a building should be planned in all its parts 
so as to shed water, and not invite the entrance of damp- 
ness into its exterior walls, so in its general shape and 
disposition it should be planned so that the sun may dry 
out its walls quickly after rains, and keep them clean and 
bright. 



44 



ORIENTATION OF BUILDINGS 






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SHADOW DIAGRAMS 



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4 6 



ORIENTATION OF BUILDINGS 











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SHADOW DIAGRAMS 



47 



So far we have considered only the distribution of sun- 
light upon the exterior surfaces of buildings and upon the 
ground. The admission of sunlight to the interior of build- 
ings through windows will next be considered. 

It is evident that a window facing the east, and with an 
unobstructed outlook, will receive its maximum of sunlight 
at sunrise of the equinoctial periods. 

As the sun moves toward the south and mounts higher and 
higher in the heavens, his rays fall more and more obliquely 



145' 




Fig. 30. — Showing the visual angle of an ordinary window, in a building of 
frame construction. 



through the opening, and finally cease to come through at 
all. The angle at which this will occur varies with the width 
and height of the opening and the depth of the jamb. 

Fig. 30 is the plan of a window of ordinary width in 
a wall of frame construction. The angle of 145 shown 
upon the diagram may be called the visual angle of the 
window. 

If the thickness of the wall is increased the visual angle 
is restricted and consequently the length of time during 
which the window will admit sunlight is diminished. 



4 8 



ORIENTATION OF BUILDINGS 



By increasing the width of the opening the visual angle 
may be enlarged but will always be less than 180 . 




Fig. 31. — Chancel window, Great Casterton Church, Rutland; from An Analysis 
of Gothick Architecture, by R. and J. A. Brandon. London, 1849. 



The full visual angle of 180 can only be obtained in 
the oriel or bay window. We are accustomed to think of 
bay windows as having a southerly exposure, when, as a 



SHADOW DIAGRAMS 49 



matter of fact, their greatest usefulness is found when 
they are projected from the north side of a building to 
catch the oblique rays of the morning sun, which would 
be shut out of a window set in the plane of the wall. 

Bay windows are of great use also for city buildings 
upon narrow streets, where the buildings opposite shut out 
the sunlight except when it falls in an oblique direction 
from either side. 

The visual angle of a window may be increased by 
beveling the jambs, with the advantage that the light is 
increased without any increase in the glass surface, and 
consequent loss of heat by radiation. 

The advantage of the beveled jamb was well understood 
by the mediaeval builders (Fig. 31). 



10 

i_j 1 1 1 1 — 1 — i— i— i— 1 

FEET 
Fig. 32. — Wall section of factory building on Swett St., Boston. 

Fig. 32 illustrates the wall section of a factory building 
designed by the author, in which the piers between the 
windows are reduced to a minimum width and are also 
beveled, affording the maximum of light. 

For the following series of window diagrams a window 
has been assumed 3 ft.— 6 in. wide, and 8 ft.-o in. tall, 
with a wall thickness of 1 ft.-o in., giving a visual angle 



ORIENTATION OF BUILDINGS 



of i48 c -6' and a normal area of opening of 28 square 
feet. 

The diagrams (Figs. 33 to 35) represent the plan of a 
room 24 feet square, lighted by a single window of the 
dimensions given and with the window sill at a height 
of 2 feet above the floor. 







* v \ V. 1/ ''' ' 



\\ \ \ 




Fig. 11. — Showing the area of floor subject to direct sunlight, for windows of 
different aspects; winter solstice; Lat. 42°-o' N. 



SHADOW DIAGRAMS 



51 



The parallelograms in dotted lines, somewhat resembling 
a deformed pack of cards spread upon the floor, indicate 
the areas in sunlight at successive hours, and the curved 
figures resulting therefrom the whole area subjected to 





iiiiiiinniin 








IjTlTffm^iiiii^HtnilTill 




Fig. 34. — Showing the area of floor subject to direct sunlight, for windows of 
different aspects; autumnal and vernal equinox; Lat. 42°-o' N. 



52 



ORIENTATION OF BUILDINGS 



sunlight, for the various exposures and at the various 
seasons indicated. 

If the room of our diagram were carpeted with a 
dark material having the property of becoming instantly 
bleached by exposure to direct sunlight, it would present 









+^-■""""'.--'1 bfl 

*/ y ..,,,'■ i ' 


1 


\ 





Fig. 35. — Showing the area of floor subject to direct sunlight, for windows of 
different aspects; summer solstice; Lat. 42°-o' N. 



SHADOW DIAGRAMS 



53 



an appearance at the end of the day corresponding to 
these diagrams. 

The rays of sunlight passing through any aperture, as 
a window, form a prism, the cross section of which changes 
as the angle of sunlight changes. The area of such a 
cross section is the normal area of the aperture for the 
admission of sunlight at the particular instant at which 
it is taken. The cross section of such a prism may be 
found by descriptive geometry. 






















vi vii viir ix x xi 

Fig. 36. — The parallelograms in the lower part represent the cross sections 
of the sunlight prism of an east window, for the hours indicated, at the autumnal 
and vernal equinox. The figure in the upper part is a graphic representation of 
the total quantity of sunlight admitted by the window, and is identical with the 
corresponding one of Fig. 38, but at a larger scale. Dimensions of window: 
3 ft.— 6 in. wide, 8 ft.-o in. tall, and 1 ft.-o in. wall thickness. 



The parallelograms in the above diagram (Fig. 36) rep- 
resent the cross sections of the sunlight prism of an east 
window of the dimensions assumed, taken at intervals of 
one hour, at the period of the equinoxes. 



54 ORIENTATION OF BUILDINGS 

The areas of these sections are as follows: 

a.m. Square Feet. 

6 28.00 

7 25.05 

8 20.39 

9 14-50 

10 7-86 

11 1-35 

11. 17 o. 

These areas may be represented by lines of varying length 
and are so represented by the vertical lines above them. 

Joining the extremities of these lines by a curve, we 
obtain a figure the height of which at any point will repre- 
sent the area of the sunlight prism at the corresponding 
hour, and the area of the whole figure the total amount 
or quantity of sunlight admitted by the window during 
the day. 

It is in this manner that the figures of the succeeding 
diagrams (Figs. 37, 38, and 39) have been drawn. 1 

In order to compare these areas we will take as a unit 
the quantity of sunlight which passes through an opening 
one foot square, in a plane normal to the sun's rays, in 
one hour. 

The areas of the figures may then be expressed in terms 
of this unit, which for convenience we will call a sun hour, 
as in Table II. 

The heating effect of the sun hour will, of course, 
vary with the altitude of the sun and atmospheric condi- 

1 Each division of the vertical scale in these figures corresponds to ten square 
feet. 

















































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V VI VII VIII IX X XI XII I II III IV V VI VII 



Fig. 37. — Showing the quantity and duration of direct sunlight admitted by 
windows of different exposures; winter solstice; Lat. 42°-o' N. Note the large 
amount admitted by the south window. For the areas of these figures see Table 
II, page 58. SS 




Fig. 38. — Showing the quantity and duration of direct sunlight admitted by 
windows of different exposures; autumnal and vernal equinox, Lat. 42°-o' N. 
Note that the amount admitted by the south window is much less than in the 
preceding diagram. For the areas of these figures see Table II, page 58. 56 




Fig. 39. — Showing the quantity and duration of direct sunlight admitted by- 
windows of different exposures; summer solstice; Lat. 42°-o' N. Note the small 
amount admitted by the south window. For the areas of these figures see 
Table II, page 58. 57 



58 



ORIENTATION OF BUILDINGS 



tions. However, an approximate value may be assigned 

to it. 

TABLE II 

TABLE OF WINDOW VALUES EXPRESSED IN " SUN HOURS " 



:> 


Winter 
Solstice. 


Equinoxes. 


Summer 
Solstice. 


North 

Northeast and northwest 

East and west 

Southeast and southwest 


32.9 
108.5 

152.9 


18.6 
82.7 

IOS-5 
81. 1 


6.8 

73-2 

no. 7 

53-4 
16. 2 


South 



An average of twelve observations taken at the Astro- 
physical Observatory in Washington in 1902-3, under the 
direction of Mr. C. G. Abbot, 1 gives the intensity of the 
solar rays at the earth's surface in the afternoon, as 1.24 
small calories per square centimeter per minute. Trans- 
posing this value, we obtain for the energy contained in a 
prism of the sun's rays one foot square in section shining 
for one hour (the sun hour of our diagrams), the equiva- 
lent of 274 British thermal units; an amount of energy, 
which, if it could be entirely converted into heat would 
be sufficient to raise one gallon of water 33 F., or 150 
cubic feet of air ioo° F. in temperature. 

The determination of the solar constant, or the intensity 
of the solar rays in space, at the mean distance of the 
earth, is one of the most difficult problems in physical 
science, since the amount of heat absorbed by the earth's 
atmosphere cannot be directly measured, but must be cal- 
culated theoretically. 

It may well be that the term solar constant is in it- 
self an unwarranted assumption and one that has tended 

1 Smithsonian Miscellaneous Collections, Volume XLV. 



SHADOW DIAGRAMS 



59 



to mislead the experimenter, since recent investigations 
appear to show that the heat emitted from the sun is not 
steadily uniform but fluctuates in some degree, in a man- 
ner not yet satisfactorily accounted for. 

The foregoing diagrams are calculated for windows with 
unobstructed outlook. The effect of an obstruction will 
now be considered. 




Fig. 40. — Showing the obstructed horizon of city buildings. No sunlight can 
come into the window until the plane of the sun's rays has reached the altitude AP. 



As an example of obstructed outlook, frequent in cities 
and towns, we shall take the case of a lower-story window 
facing a row of buildings 60 feet away. We shall assume 
the cornice line of these buildings to be 40 feet above the 
ground and to extend indefinitely in both directions from 
the point opposite our window. 

The assumed conditions are shown in Fig. 40. 



60 ORIENTATION OF BUILDINGS 

It is clear that no sunlight can come into the window 
until the plane of the sun's rays has reached the altitude 
AP, but that after the altitude BP has been reached the 
obstruction will have no further effect. 

The hour angles corresponding to these altitudes may 
be calculated. 

Let it be required to find the time at which the sunlight 
will first come into a window with an east exposure, under 
the conditions assumed in the diagram, and at the period 
of the winter solstice. 

The angular altitude of the obstruction above the top 
of the window {i.e. the slope of the line AP) is found by 
measurement to be 22°-37' and the problem consists in 
determining the hour angle at which the plane of the sun's 
rays will reach this elevation. 

For the purpose of representing the problem it will be 
convenient to use the stereographic projection (Fig. 41). 
The enclosing circle is the horizon; NS the meridian; P the 
celestial north pole; the dotted circle the path of the sun 
at the winter solstice, and NXS a great circle of the sphere 
formed by a plane intersecting the plane of the horizon on 
the north and south line and making an angle of 22°-^' 
with it. 

The intersection of this circle with the dotted circle (at 
the point X) determines the position of the sun required, 
and the calculation of the spherical triangle SPX gives 
us the hour angle (at P) which we find to be /\o°-/[Y , corre- 
sponding to 9 I1.-17 m. a.m. solar time. 

Similarly the hour angle corresponding to the elevation 
BP is found to be 35°-32' or 9 I1.-38 m. solar time. In 



SHADOW DIAGRAMS 



61 



other words, the effect of the obstruction is to cut off all 
sunlight from this window until 9 h.-i7 m. a.m. and a 
portion of the sunlight from 9 I1.-17 m. to 9 I1.-38 m., 
after which the obstruction ceases to have any further 
effect. 




Fig. 41. — Use of the stereographic projection to represent the conditions 

shown in Fig. 40. 



In the case of the southeast window the obstruction is 
complete until 10 I1.-27 m. and partial until 11 h.-20 m. 

In the case of the south window the obstruction is com- 
plete before 10 h-24 m. a.m. and after 1 h-36 m. p.m., 
between which hours the obstruction is partial. 



62 



ORIENTATION OF BUILDINGS 



For the southwest and the west windows the effects 
correspond to those for the southeast and east windows. 
The results are shown in diagrammatic form in Fig. 42. 























































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Ifesw 




















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1 
















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1 

1 


























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1 
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V 


[IV. 


[II I 


X ) 


Li 


I X 


II 


II III I 

1 


V A 


T 



Fig. 42. — Showing the quantity and duration of direct sunlight admitted by 
a window with obstructed outlook, under the conditions shown in Fig. 40, for 
different exposures; winter solstice; Lat. 42°-o' N. The full areas of the figures 
are identical with those of Fig. 37; the shaded portions show the quantity of sun- 
light admitted by the obstructed window. 

It may be noted from these window diagrams that the 
unobstructed south window in winter admits more sun- 



SHADOW DIAGRAMS 63 



light than any of the other exposures, at any period of 
the year, while the same window in summer admits less 
than any of the other exposures, except the north. The 
effect of obstruction, however, is serious upon the south 
window in winter, when sunlight is most to be desired. 

The southeast and southwest windows partake to some 
degree of the character of the south window, in that they 
show a maximum in winter and a minimum in summer, 
although the variation is not as great as in the south 
window. 

The east and west windows on the contrary show a 
maximum in summer and a minimum in winter, and are 
consequently less desirable exposures than the south, south- 
east, or southwest. 

The results thus theoretically obtained may be confirmed 
in a striking manner with a sun box. 

A sun box is essentially a box or chamber of non-heat- 
conducting material, having on one side a window or light 
of glass, sealed tight to prevent air leakage. 

Such a box, when the window is turned toward the 
sun, will accumulate heat much faster than it is lost by 
radiation. 

Fig. 43 illustrates the construction of the sun boxes 
employed by the author in experiments at Boxford, Mas- 
sachusetts (Lat. 42°-4o' N.). 

Two of these boxes were made, as nearly alike as 
possible. 

They were constructed of ordinary pine boards § inch 
thick, nailed together, without grooving or dovetailing. 

The inner box (1 foot square, inside measurement) 



64 



ORIENTATION OF BUILDINGS 



was covered with one thickness of lino-felt (a non-heat- 
conducting material made of flax fiber quilted between 
two thicknesses of building paper). 




Fig. 43. — Cross-section of sun box. A. Hood or cover. B. Outer box. 
C. Air space. D. Lino-felt. E. Inner box. T. Thermometer. S. Shield. 



The sash (glazed with |-inch plate glass) was screwed 
into place and fitted tightly against a felt weather strip 
all around the edges. 

The boxes were painted on the outside one coat of white 
paint and were shielded from the sun's direct rays, except 
on the window side, by wooden hoods or covers. 



SHADOW DIAGRAMS 



65 



The temperature of the air inside the boxes was shown 
by a thermometer on the rear wall, in front of which was 
placed a wooden screen, sufficiently tall to shield the bulb 
from the sun's direct rays, while permitting the scale to 
be read from the outside. 1 




Fig. 44. — View of sun boxes. 

The boxes were exposed to the sun on a platform about 
three feet above the ground, in an open field, with free 
access of sunlight from every quarter (Fig. 44). The 
platform was marked with a system of lines running north 
and south, and east and west, with diagonals in both 

1 The protecting covers and thermometer shields were omitted in the first 
few experiments. 



66 ORIENTATION OF BUILDINGS 

directions, so that it was a simple matter to set the boxes 
facing in any direction desired. 

In the earlier experiments the boxes were unsealed at 
the close of each day and allowed to remain until the 
temperatures were the same in each, when they were again 
sealed up and set for the next experiment. In the later 
experiments this was not done, as it was found that the 
temperatures became equalized by radiation during the 
night. 

Notwithstanding the fact that the boxes were of the 
same shape, size, and construction, it was found that there 
was a difference between them, as shown by the experi- 
ments of July 14 and 15, in which both boxes were set for 
the same exposure and yet showed a difference of several 
degrees in temperature under apparently the same con- 
ditions. 

For this reason the experiments do not afford an absolute 
basis of comparison between different exposures, such as 
might be obtained with apparatus more carefully made 
and experiments more carefully conducted. 

By comparing the records for the same box, however, 
the relative efficiency of the same exposure at different 
periods of the year is shown with sufficient exactness, and 
follows quite closely the theoretical conclusions deduced 
from the diagrams. 



SUN BOX RECORDS 



The following is a record of experiments made with these boxes during 
the season of iqio. All of them (except as noted) were made on clear, 
bright days, with few or no clouds. All temperatures are in degrees 
Fahrenheit and all hours in solar time. 



67 



68 



ORIENTATION OF BUILDINGS 



JUNE 26 





Time. 


Air. 


Box A, East. 


BoxB, South. 




A.M. 








I 1 


5-48 


63 


72 


54 


2 


6.36 


66 


80 


57 


3 


7.08 


74 


IOO 


62 


4 


8. 


73 


124 


68 


5 . 


9-38 

P.M. 


So 


122 


-85 


6 


12.33 


85 


I05 


no 


7 


i-33 


85 


I05 


112 


8 


2.23 


85 


I03 


108 


9 


3-53 


85 


IOO 


104 


10 


6.58 


72 


85 


85 


11 


7.18 


70 


83 


83 



Remarks. — No hoods on boxes. No shield for thermometers in boxes. 

1. Both boxes wet with dew. Glass wet on B. Sun partially obscured 
by haze. Later on the haze wore off and it was a fine day, with flying 
clouds. 



JUNE 29 





Time. 


Air. 


Box A , East. 


Box B, Southeast. 




A.M. 








I 


5.28 


62 


90 


54 


2 


6.20 


69 


114 


67 


3 


7-33 


71 


138 


92 


4 


8.28 


71 


137 


97 


5 


9.28 


72 


123 


114 


6 


10.28 


75 


117 


117 


7 


11.28 

P.M. 


76 


107 


114 


8 


1 -13 


77 


IOO 


103 


9 


3-i3 


77 


93 


95 


10 


4-43 


77 


• 90 


9i 


n 


6.28 


78 


85 


86 


12 


9-13 


52 


66 


65 



Remarks. — No hoods on boxes. 
Remarkably clear day. 

1. Glass of B covered with dew. 

2. Dew has disappeared. 
5. Glass on A misty. 

7. Glass on A clear. 



No shields for thermometers in boxes. 



SHADOW DIAGRAMS 



69 



JUNE 30 





Time. 


Air. 


Box A , West. 


Box B, South. 




A.M. 








I 


7-7 


78 


62 


64 


2 


9.17 


82 


78 


88 


3 


10.42 


82 


88 


102 


4 


11.42 

P.M. 


84 


94 


no 


5 


I. 12 


84 


102 


112 


6 


2. 17 


86 


118 


no 


7 


3-i7 


84 


138 


IOzl 


8 


4.27 


84 


144 


100 


9 


5-27 


80 




98 


10 


6.27 


72 


112 


88 


11 


6-57 


67 


102 


85 



Remarks. — No hoods on boxes. No shields for thermometers in boxes. 

8. The temperature of 144 recorded in Box A is the highest which the 
thermometer registers. 

9. Glass in A misty so that thermometer cannot be seen. 



JULY s 





Time. 


Air. 


Box A , South. 


Box B, Northeast. 




A.M. 








I 


6.06 


72 


47 


80 


2 


7.06 


72 


54 


98 


3 


8. 11 


80 


70 


108 


4 


9. 11 


84 


82 


no 


5 


10. 11 


84 


99 


108 


6 


11. 41 

B.M. 


84 


no 


106 


7 


12.41 


86 


116 


106 


8 


1. 41 


87 


117 


104 


9 


2.26 


88 ■ 


116 


102 


10 


4. II 


86 


106 


100 


n 


5-H 


86 


102 


96 


12 


7-5i 


64 


84 


82 



Remarks. — No hoods on boxes. Clear day. 
1. Glass of A covered with dew. 



7° 



ORIENTATION OF BUILDINGS 



JULY 7 





Time. 


Air. 


Box A , South. 


Box B, East. 




A.M. 








I 


6. ii 


55 


48 


85 


2 


7.00 


63 


55 


108 


3 


7-31 


68 


60 


115 


4 


9-36 


82 


84 


132 


5 


10.41 


86 


96 


122 


6 


11. 41 

P.M. 


86 


106 


112 


7 


12.41 


88 


112 


I06 


8 


I . 26 


90 


112 


I02 


9 


3.0I 


88 


108 


98 


IO 


3-51 


84 


100 


94 


ii 


4.46 


98 


98 


96 


12 


5-41 


92 


94 


92 



Remarks. — No hoods on boxes. Perfectly clear day. 

11. Air thermometer in direct sunlight.., 

12. Air thermometer in direct sunlight. 



JULY ro 





Time. 


Air. 


Box A , South. 


Box B, East. 




A.M. 








I 


5-36 


62 


62 


68 


2 


7-5i 


80 


72 


no 


3 


8.26 


84 


77 


117 


4 


9.26 


91 


87 


124 


5 


10. 26 


96 


99 


124 


6 


11 .41 

P.M. 


IOO 


no 


118 


7 


12.41 


102 


116 


114 


8 


I .06 


IOO 


117 


112 


9 


i-5i 


IOO 


118 


109 


10 


2.41 


95 


114 


106 


11 


3-4i 


94 


no 


104 


12 


4-51 


91 


i°5 


IOO 



Remarks: — 
1. Slight haze: humidity high. 

7. Floating clouds. 

8. Floating clouds. 

9. Thunder clouds. 
12. Clear: good breeze. 



SHADOW DIAGRAMS 



71 



JULY 14 





Time. 


Air. 


Box A , East. 


Box B, East. 




A.M. 








I 


6. 10 


61 


98 


100 


2 


6.50 


71 


118 


121 


3 


7.40 


74 


126 


131 


4 


8.10 


78 


132 


136 


5 


g.io 


80 


136 


138 


6 


10.10 


88 


138 


138 



Remarks. — Clear day. Boxes placed side by side, B being to the 
north of A . 

JULY 15 



Time. 


Air. 


Box A , East. 


Box B, East. 


A.M. 








6-55 


68 


102 


I02 


7-35 


70 


"5 


117 


8.10 


76 


124 


126 


0. 10 


80 


132 


130 


10. 10 


82 


128 


128 



Remarks. — Somewhat cloudy in early morning 
placed side by side, A being to the north of B. 



clear later. Boxes 



JULY 20 



Time. 


Air. 


Box A, East. 


Box B, Southeast. 


A.M. 








5- 


5° 


60 


52 


6.40 


59 


105 


76 


7- °5 


62 


114 


84 


7-35 


65 


120 


94 


7-55 


68 


126 


102 


8.25 


70 


122 


IO4 


8. 55 


76 


Il8 


I06 


9- 2 5 


76 


Il8 


I08 


9-55 


78 


I20 


no 


10.25 


78 


no 


112 


11 . 10 


76 


106 


no 


n-55 


78 


I02 


108 


P.M. 








12.25 


78 


96 


100 


2.25 


78 


86 


86 


3-55 


78 


82 


82 



Remarks. — Clear day. 



72 



ORIENTATION OF BUILDINGS 



JULY 21 





Time. 


Air. 


Box A , Southeast. 


Bos B, East. 




A.M. 








I 


5- 


56 


54 


56 


2 ) 


6.40 


64 


74 


96 


3 


7-05 


66 


82 


105 


4 


7-35 


68 


9 1 


116 


5 


8. 


72 


98 


129 


6 


9- 


76 


no 


128 


7 


10.45 


86 


120 


118 


8 


11.45 

P.M. 


90 


118 


112 


9 


12-35 


94 


112 


108 


IO 


2-15 


90 


102 


102 


ii 


3-3° 


86 


98 


98 


12 


5.20 


80 


90 


90 



Remarks: 

1. Sun rising through cloud bank. 
3. Perfectly clear. 



JULY 24 



Time. 


Air. 


Box A, Southwest. 


Box B, Southeast. 


A.M. 








8.04 


78 


67 


86 


8.44 


84 


72 


98 


9-34 


88 


78 


108 


10. 19 


9° 


85 


116 


10.54 


94 


92 


118 


n-54 


99 


104 


120 


P.M. 








i-39 


98 


III 


112 


2.49 


96 


114 


107 


4-39 


94 


122 


102 


5- 


94 


121 


IOI 


5-24 


92 


116 


100 



Remarks. — Somewhat cloudy day. 



SHADOW DIAGRAMS 



73 



AUGUST 7 





Time. 


Air. 


Box A , South, 


BoxjB, East. 




A.M. 








I 


7-45 


68 


61 


121 


2 


8-35 


72 


68 


I30 


3 


9- 


71 


73 


I30 


4 


9-35 

P.M. 


76 


81 


129 


5 


12. IO 


8l 


105 


108 


6 


i-45 


■ 83 


104 


102 


7 


4.40 


77 


96 


90 


8 


6-35 


68 


84 


80 



Remarks: 

3. Sun behind thin clouds. 

6. Sun behind clouds. 



AUGUST 21 



Time. 


Air. 


Box A , West. 


Box B , Southeast. 


A.M. 








8.28 


72 


56 


104 


9-!3 


75 


60 


114 


10.13 


80 


67 


123 


11.08 


80 


72 


125 


P.M. 








1 -13 


81 


88 


no 


1-53 


79 


97 


104 


2.08 


76 


118 


94 


3-33 


76 


123 


9i 


4-i3 


76 


132 




6.48 


67 


103 


76 



Remarks. — Clear day. 



74 



ORIENTATION OF BUILDINGS 



AUGUST 28 





Time. 


Air. 


Box A , South. 


Box B , Southeast. 




A.M. 








I ■> 


7 


14 


65 


46 


76 


2 


8 


29 


7° 


61 


102 


3 


8 


59 


72 


68 


no 


4 


9 


29 


74 


77 


116 


5 - 


11 


14 


78 


114 


123 


6 


11 


50 


78 


112 


119 




P.M. 








7 


12 . 20 


80 


117 


118 


8 


12 .40 


80 


117 


114 


9 


i-5° 


82 


120 


107 


10 


2.30 


S3 


11S 


103 


11 


5- 


70 


95 


86 


12 


7-14 


63 


75 


72 



Remarks: 

6. Slightly cloudy. 

7. Clear again. 

8. Slightly cloudy. 

9. Slightly cloudy. 
10. Clear. 



SEPTEMBER 18 



Time. 


Air. 


Box A , South. 


Box B, East. 


A.M. 








6.31 


47 


44 


57 


7.40 


60 


5i 


97 


8.46 


68 


68 


112 


9. II 


69 


75 


114 


936 


72 


85 


114 


IO.51 


76 


104 


106 


II . 26 


77 


113 


102 


P.M. 








12.51 


82 


127 


95 


2. l6 


81 


127 


93 


3.06 


82 


122 


92 


4.l6 


80 


no 


89 


5.06 


76 


100 


85 


7.l6 


70 


82 


76 



Remarks. — Clear day. 



SHADOW DIAGRAMS 



75 



OCTOBER 24 


Time. 


Air. 


Box A , South. 


Box B, East. 


A.M. 








6.19 


32 


32 


32 


7- 


36 


33 


45 


7-46 


39 


42 


70 


8. 11 


4i 


50 


80 


8.31 


42 


58 


87 


9.04 


44 


70 


92 


9-3 1 


45 


79 


93 


10.46 


5° 


IOI 


85 


11. 51 


5 2 


116 


74 


P.M. 








12. II 


55 


119 


72 


I. II 


57 


123 


68 


1-33 


58 


125 


67 


i-5S 


59 


125 


67 


2. 11 


59 


124 


66 


3-03 


58 


107 


64 


4.41 


53 


84 


60 


6.31 


46 


63 


52 



Remarks. — Remarkably clear day. 

DECEMBER 22 





Time. 


Air. 


Box A , South. 


Box B, East. 




A.M. 








I 


9-47 


16 


56 


45 


2 


10.57 

P.M. 


20 


88 


46 


3 


12.52 


24 


114 


38 


4 


I .42 


25 


"5 


44 


5 


3.22 


24 


94 


33 



Remarks. — Clear day. . 

4. The reading in Box B is probably an error. 



7 6 



ORIENTATION OF BUILDINGS 



6789 10 11 12 123456 



100 




JUL. 7 



100 













^-— 








































~"">><C___ 
















vf 




_L^ 











































--^" 






















,"" ^ 






















•ZZ~- 


~~ 8 































































































SEP. 18 



100 

























































































x^ 
















































[ 


y 






































_____ 










■^-K 


_^- 


U=— 


*= — 














— 


-^-- 















































































OCT. 24 



100 







































/- 
























■ / 




































































y 
































































































_l 






















— 


— -- 


"" ' 















DEC. 22 

Fig. 45. — Sun-box records for south and east exposures. The dotted lines 
show the temperature of the air; the full lines the temperatures within the boxes. 
The figures at the top denote the hours of the day. The divisions of the vertical 
scale are equal to ten degrees of temperature. 



SHADOW DIAGRAMS 



77 



The records of July 7, September 18, October 24, and 
December 22 are shown graphically in Fig. 45 the tempera- 
ture being plotted in the form of curves; the dotted curve 
showing the temperature of the air outside and the solid 
curves that of the air within the boxes. 




Fig. 46. — Mr. Cabot's sun house. 



Each horizontal division of the scale corresponds to one 
hour of time and each vertical division to io° of tem- 
perature. 

The boxes occupied the same relative position in all 
four experiments, so that the records show very well the 
change in efficiency of the same exposure with the change 
of seasons. 



78 ORIENTATION OF BUILDINGS 

That the sun's rays are not of indifferent value in the 
heating of our houses in winter is shown by the last ex- 
periment (December 22), in which the air within the sun 
box reached a temperature of 115 F. with the air outside 
at 25 F. 

Every dwelling may be converted into a sun box by 
properly insulating the outside walls. Fig. 46 is reproduced 
from a photograph of a "sun house" built by the late Mr. 
Samuel Cabot, on his place at Canton, Massachusetts. 
This little building faces the south, on a southerly slope, 
and is quite shallow in proportion to its breadth. 

The walls and roof are thoroughly insulated. 

A temperature of ioo° F. and over has been frequently 
attained within this building with an outside temperature 
of zero or lower, entirely from the warmth of the sun's 
rays. 

The foregoing study of windows has an important bear- 
ing on the orientation of hospital buildings, and in the next 
chapter we shall take up the question of hospitals in some 
detail. 



CHAPTER III 
Hospitals 

The typical hospital ward is a long, narrow room, with 
windows on both sides, between the beds. In the open- 
ended type of ward there are windows also at one end, 
and these are of great value, especially in winter, as will 
presently be shown. 

A typical ward pavilion of the open-ended type is shown 
in Fig. 47. 

There is a difference of opinion as to the best orientation 
for ward pavilions. 

In a description of the Heidelberg University Hospital, 
given in Mouatt & Snell's Hospital Construction and Man- 
agement, it is stated that "The question of the aspect 
of the windows of the wards was only settled after very 
great deliberation by the authorities charged with the 
erection of this building, and Dr. Knauff gives in his work l 
a very exhaustive account of the considerations ^which 
ultimately led to the determination of the placing of the 
axes of the various pavilions as nearly east and west as 
the shape of the ground would permit. Actually their 
direction is about E. S. E. and W. N. W. It is remarkable 
that the Friedrichshain building authorities, as the result 
of their deliberations on this question, arrived at an exactly 
opposite conclusion, and placed the axes of their pavilions 
directly north and south." 

1 Das Neue Academische Krankenhaus in Heidelberg, Munchen, 1879. 

79 



8o 



ORIENTATION OF BUILDINGS 




Fig. 47. — Typical one story ward pavilion of twenty-four beds. This plan is not 
given as an example to be followed, but to illustrate several common faults. 
The orientation is bad, giving the minimum of sunlight in winter and the max- 
imum in summer. The arrangement of the windows, one for each two beds, is not 
as good as one for each bed. The ward itself has excessive length in proportion 
to its width, giving an unpleasing effect to the interior, and the distance to be 
traversed by the nurses, in going to and from the service rooms, is excessive. 

A good feature of the plan is the large bay window at the south end; if it were 
not for this the ward would have very little sunlight in winter. The building 
would be improved by making the service portion (shaded), two stories in height, 
after the manner of the Virchow ward unit. (See Fig. 56.) 



HOSPITALS 



In the Handbook for Hospitals [No. 32 of the pub- 
lications of the State Charities Aid Association of New 
York (N.Y., 1883)], it is recommended that the long axes 
of the wards should run as nearly as possible from north- 
east to southwest. 

The majority of those, however, who have written on 
hospital construction incline to a north and south direc- 
tion. 

This is the orientation recommended by Sir Douglas 
Gal ton (Healthy Hospitals, Oxford, 1893): 

"The arrangement by which sunshine will always fall 
to the largest extent on the space between pavilions, and 
also be distributed most evenly upon the wall surface, is 
obtained in this country (England) by placing the pavilions 
on a north and south line or axis, because the slanting 
rays of the sun fall in the morning on the eastern and in 
the evening on the western side." 

There is also a wide variation in practice. 

In a list of thirty-eight hospitals given in Mouatt & 
Snell's work, there are thirteen in which the pavilions are 
placed approximately north and south; fifteen in which 
they are placed approximately east and west; six in which 
they are placed approximately northwest and southeast, 
and four in which they are placed approximately northeast 
and southwest. 

Let us examine the questions in the light of what we have 
already learned about windows. 

For an example we shall take a ward with unobstructed 
outlook, having ten of our typical windows (3 ft.— 6 in. by 
8 ft.-o. in.) on each side and none at the ends. 



82 



ORIENTATION OF BUILDINGS 



Using the factors in Table II, giving the quantity of 
sunlight, in "sun hours," admitted by windows of different 
exposures, we obtain the following results: 

TABLE III 



Axis. 


Winter Solstice. 


Equinoxes. 


Summer 
Solstice. 


North and south 


658 
1085 
1085 
1529 


1652 

1241 

1241 

811 


2214 


Northeast and southwest 


Northwest and southeast 


1266 


East and west 


230 





By adding three windows at the end of the ward the 
results are somewhat modified, as shown in the following 
table: 



TABLE IV 



Axis. 


Winter Solstice. 


Equinoxes. 


Summer 
Solstice. 


North and south 


1116. 7 
1410.5 
1410.5 
1627.7 


1895.8 
1557-5 
1557-5 
1058.8 


2262 . 6 


Northeast and southwest 

Northwest and southeast 


1426.2 

1426. 2 

562.I 


East and west 





In both cases, the ward placed with its axis north and 
south receives the least sunlight in winter, when sunlight 
is most needed, and the maximum in summer, when it is 
least to be desired. 

In the east-and-west position the results are reversed, 
showing a maximum in winter and a minimum in summer. 

If we were to base our judgment wholly on the amount 
of sunlight received by windows, we should be led to follow 
the conclusion of Dr. Knauff, that the best position for 
such a building is with its long axis placed east and 
west. 



HOSPITALS 83 



There are two disadvantages, however, in the east-and- 
west position; the first that it involves an area of complete 
shadow, on the north side of the building, during one-half 
the year, and the second that in this position a greater 
distance is necessary between the pavilions than in any 
of the other positions considered. 

The north-and-south position has all of the disadvantages 
of the east-and-west position and none of the advantages. 
The windows admit little sunlight in winter and an exces- 
sive quantity in summer. If conditions make it necessary 
to adopt this orientation, the wards should always have 
windows at the south end. 

There remain to be considered the two intermediate posi- 
tions, northeast-southwest and northwest-southeast. 

In both of these there is little variation in the amount 
of sunlight received at different seasons, and by placing 
windows at the southeast or southwest end, as the case 
may be, the amount of sunlight in winter is very much 
increased. 

Furthermore, the buildings may be placed closer to- 
gether than in either of the other two positions, and may 
be so planned that all of the outside walls are exposed to 
the sun at some portion of the day throughout the year; 
and this advantage is obtained not only for the wards, 
but also for the other buildings of the hospital group, 
which is not possible where a north-and-south, east-and- 
west system of axes is adopted. 

As between the northeast-southwest and the northwest- 
southeast positions, the only difference is that in the former 
the broad side of the buildings is exposed to the sunlight 



8 4 



ORIENTATION OF BUILDINGS 



in the forenoon, while in the latter the reverse effect is 
obtained. This indicates a slight advantage for the former, 
since the forenoon sunlight is more generally prized than the 
afternoon sunlight, probably because it is constantly in- 
creasing in amount, while in the afternoon it is constantly 
decreasing. 

We are, therefore, led to recommend that for hospital 
buildings in or near the latitude considered in this book, the 
long axis of the wards should be placed as nearly northeast 
and southwest as possible, and, furthermore, that the south- 
west ends of the pavilions should always have windows. 




Fig. 48. — Illustrating the French method of arranging outside blinds, so as to 
fold back against the jamb. This is the ideal arrangement for a hospital building. 

The ward windows should always be provided with 
blinds, shutters, or shades. 

Outside blinds, folding back against the jamb, are pro- 
tected from the wind and weather, and are easily reached 
from the inside. With a window of 3 ft. -6 in. opening, 
which goes well with a lineal bed space of 8 ft.-o in., a 
reveal of ten inches affords the requisite space for outside 
blinds of this type. A detail of the arrangement is shown 
in Fig. 48. 



HOSPITALS 85 

This method of hanging blinds is customary in France 
and deserves to be more generally used. It is better than 
the American method, in which the blinds open back 
against the outside wall, where they rattle in the wind, 
are exposed to the sun and rain, and are, moreover, 
exceedingly troublesome to operate. 

The ward pavilion is the unit of hospital construction, 
and the essential problem in planning a hospital is in the 
design and grouping of these units. 

The typical ward unit is a one-story building, although 
there are many examples of hospitals built on the pavilion 
plan in which the pavilions are two, and even three stories 
in height. 

There is an economy of construction in the super- 
position of stories, and although the buildings require to 
be placed at a greater distance apart to secure adequate 
sunlight, there is, notwithstanding, an economy of land as 
well. 

This is illustrated in Fig. 49 in the upper part of which 
are shown, in section, four one-story pavilions, spaced at 
a distance apart equal to one and one-half times their 
height. In the lower part of the same diagram are shown 
two pavilions of two stories each, also at a distance apart 
equal to one and a half times their height. 

The number of patients accommodated is the same in 
both arrangements, but the amount of land required for 
the two-story pavilions, although the distance between 
them is greater, is less than for the one-story pavilions. 

If we consider not only the cross section, but also the 
plan, a further economy will appear in favor of the two- 



86 



ORIENTATION OF BUILDINGS 



story arrangement; for, the length of the buildings remain- 
ing the same in both cases, an increase of distance between 
them reduces the proportional depth of the U court between 
the buildings, making it more open to the sun. It follows, 
therefore, that the distance between pavilions should be 
governed, in part at least, by their relative length, as well 
as their relative height, and it may, therefore, be justifiable 
to place two-story pavilions at a less distance apart in 
proportion to their height, than one-story pavilions of the 
same length. 




Fig. 49. — Illustrating the economy of land in the two-story type of hospital 

building. 

While economy is of importance in hospital construc- 
tion, it must always be kept subordinate to the welfare 
of the patient, for that is the whole end and aim of the 
hospital. 

"L'hopital en effet n'a qu'un seul but: chercher a guerir, 
et tout doit y concourir. . . . Et ici plus que partout 
ailleurs, l'economie est sacree, car si pour la meme somme 
on peut assurer quelques lits de plus, c'est de l'impuissance 



HOSPITALS 87 

finale de l'assistance publique diminuee d'autant. Mais 
l'economie ne doit etre cherchee au detriment de l'hygiene: 
une economie sur l'ornementation d'une facade est un 
vertu: une economie sur le cube d'air des malades serait un 
crime. L'hopital est fait pour le malade, voila ce qu'il ne 
faut jamais perdre de vue." 1 

In all respects is the one-story pavilion the best for the 
patient, but especially because it is best adapted to ven- 
tilation by natural means. 

"The amount of fresh air renewed by natural ventilation 
is infinitely greater than that which can be obtained by 
the most costly mechanical contrivances. Thus, in a room 
of the capacity of 1500 cubic meters (nearly 53,000 cubic 
feet) the air can be renewed by the opening of a single 
window in less than half an hour, with a velocity equal to 
0.50 m., or nearly two feet, in every second." (M. Toilet, 
quoted in Mouatt & Snell's Hospital Construction and 
Management.) 

Artificial or forced ventilation, which in our climate is 
a necessary evil during a large part of the year, may be 
successfully adapted to a building of superposed stories, 
as well as to a subway or a mine. But for ventilation by 
natural means nothing has ever been designed so effective 
as ridge or monitor ventilation (Fig. 50), in conjunction 
with open windows, a method of construction which is, of 
course, not possible where one ward is superposed upon 
another, except for the uppermost story. 

Several types of ward pavilions are shown in Fig. 51. 
Nos. 1 and 2 are single pavilions of the open-ended type; 

1 Elements et Theorie de L'Architecture. J. Gaudet, Paris. 



ORIENTATION OF BUILDINGS 



No. 3 a double pavilion, and No. 4 a single pavilion, both 
with closed ends. 

Nos. 1 and 2 differ only in the position of the corridor, 
which, in No. 1 runs through the service portion of the 
pavilion; 1 and in No. 2 is placed clear of the building. 




Fig. 50. — Illustrating the method of ridge ventilation for hospital ward 

pavilions. 

This is a cross section of the one-story wings of the plan shown in Fig. 58. 
(The arched form is advantageous, but is not essential.) 



The advantage of the latter arrangement is that any 
pavilion of a group may be reached without passing through 
any of the others, and the circulation through the corridor 
is unimpeded by doors. 

1 In all the figures the service portion is indicated by shading. 



HOSPITALS 



*9 



■ 



\=J 



%=£ 



1=£ 



tlJ 








I I 



50 

l 1_ 



100 150 200 
, I i I 



r 



3 



3 4 

Fig. 51. — Illustrating several types of ward pavilions. 



9° 



ORIENTATION OF BUILDINGS 



Furthermore, when a series of pavilions of the type of 
No. I are connected together, a series of U courts is created, 
facing in opposite directions, involving an area of complete 
shadow in one or the other. 

No. 2 is free from this objection. 

No. 3 is the type of pavilion adopted in the Virchow 
Hospital in Berlin. 1 It consists of two one-story wards 
joined by a central service portion two stories in height, in 
the upper part of which are lodged the nurses who have 
charge of the pavilion. 

This type of pavilion was not designed, and is not suit- 
able for, corridor connection and is therefore not likely 
to be adopted in our climate, where it is considered essen- 
tial that the pavilions should be connected by corridors. 

In both Nos. 3 and 4 the ends of the wards are blocked 
by service rooms and in No. 4 (Friedrichshain) these 
service rooms project so far as to cut off both air and sun- 
light from the ward. 

Pavilions may be grouped in various ways. 

Fig. 52 is typical of the arrangement adopted at the 
Virchow Hospital. It will be noted that the individual 
pavilions are placed quite close together and yet have 
access to large open spaces on either side. 

There seems to be no good reason why the pavilions 
of a general hospital should be placed any farther 
apart than is necessary to secure adequate sunlight and 
a free passage of air between them. Compactness saves 
steps and helps toward economy of administration. 
Furthermore, too great a space between pavilions is a 

1 Opened in 1906. Architect, Dr. Ludwig Hoffmann. 



HOSPITALS 



91 









:=3 
n 



100 

1 



200 300 400 500 



Fig. 52. — Arrangement of ward pavilions,Virchow Hospital. 

In the entire hospital there are twenty of these pavilions, besides others of a 
different type. 



Q2 



ORIENTATION OF BUILDINGS 



u 



400 



Fig. 53. — Two common methods of grouping ward pavilions. Neither one is 

recommended- 



HOSPITALS 93 

temptation to future boards of trustees, under the demands 
for increased accommodation, to fill up these spaces with 
new buildings. 

Fig. 53 illustrates two dispositions, both of which are 
symmetrical in the narrow sense of the word, and both of 
which are bad, since they involve U courts facing in opposite 



TOO 200 300 400 

FEET 

Fig. 54 — A good method of grouping ward pavilions. 

directions, and a disparity in the amount of sunlight re- 
ceived by the opposite wards. 

The arrangement shown in Fig. 54 is more truly sym- 
metrical, since all of the wards present the same exposure 
to the sun, and it is recommended as the best arrangement 
for single pavilions of the open-end type. 



94 ORIENTATION OF BUILDINGS 

Fig. 55 shows a good arrangement of buildings where 
the size of the lot does not allow of the double corridor 
plan. 

The axes of the buildings are placed very nearly northeast and southwest and 
the shadows are shown for noon, at the period of the equinoxes. 

In the conventional rendering of architectural drawings the shadows are cast 
as if the sun's rays came from the left, at an angle of 45 with the plane of the 
picture, both in plan and elevation. 

This convention is assumed irrespective of the position which the building is 
to occupy, and all the elevations of a building are treated as if they faced in the 
same direction. A facade, for instance, having a northerly exposure, will be 
represented with shadows such as could only occur on a south facade, and an 
impression of abundant sunlight is given which is not only inaccurate, but false 
and misleading. 

Such a departure from accuracy and truth is harmful in its effect upon the 
student and a careless habit is engendered of regarding the architectural drawing 
as an end in itself, while actual conditions of site, surroundings and exposure are 
lost sight of. So, too, has grown up the practice of studying an architectural 
plan irrespective of its orientation. So little is this matter regarded that it is the 
exception, rather than the rule, to find the points of the compass marked upon an 
architectural plan. 

The study of shades and shadows is regarded so entirely for its use in the con- 
ventional rendering of the elevation that it is seldom applied to the rendering of 
the plan, although it is here that its greatest usefulness is found, especially in the 
study of groups of buildings, or for the representation of landscape work. In no 
other way may the relative heights of buildings, or changes in level of a site, be 
so graphically shown in a single drawing. 

The types of pavilion so far illustrated are not well 
adapted to the requirements of modern medical treatment. 
The classification of patients according to their needs can- 
not be accomplished in a building containing but one large, 
open ward with one or two single rooms; and the open-air 
treatment, which has been found so effectual in many medical 
cases, cannot well be given except in a building especially 
designed for that purpose. 

The program has changed and a new type of hospital 
construction must be devised to meet it. 




95 



96 ORIENTATION OF BUILDINGS 

The requirements for a modern system of hospital con- 
struction adapted to a general hospital of moderate size 
may be stated as follows: 

The pavilions should be placed no farther apart (except 
for contagious cases) than is necessary to secure adequate 
sunlight and air. 

Adjacent to the pavilions, but not between them, should 
be large, open areas easily accessible to the patients. (An 
admirable example of such an open space is the famous 
Mittel Allee of the Virchow Hospital.) 

Each pavilion should provide for a subdivision of the 
patients within itself and should, therefore, contain at least 
two or more open wards of moderate size, besides a number 
of smaller wards and single rooms. 

All of the open wards should have ridge or monitor 
ventilation, and therefore one ward may not be superposed 
upon another. 

Ample facilities should be provided for open-air treat- 
ment, and these facilities should be of two kinds: open 
terraces or balconies opening directly from the wards, for 
open-air treatment in the daytime; and roofed balconies 
or loggias, which may be screened in and protected with 
blinds, affording an opportunity for patients to sleep in 
the open air. 

Each pavilion should have a day room, for those patients 
who are able to be out of bed; and the bathrooms, lava- 
tories, and other service rooms should be ample in number 
and in size. 

The working out of such a program will naturally 
result in a building having more the aspect of a large, 



HOSPITALS 97 

private house, than the long, narrow buildings which we 
have been accustomed to associate with hospital archi- 
tecture. 

The ward unit about to be described has been designed 
to fulfill this program. It is an attempt to adapt what 
may be called the "Virchow idea" to the conditions with 
which the American architect is called upon to deal, of 
which the two dominant ones are the covered corridors 
between the buildings required by our climate and the 
compactness in plan required by the custom of build- 



A 



D Q DjoDODODDDDDDapi 



ODD 

ODD 



D D D 
D D D 



pioDDaDDQDaaQojD D D 



Fig. 56. — Elevation of the Virchow unit. Each of these units is virtually a 
complete hospital in itself, the central pavilion corresponding to the administra- 
tion building of a cottage hospital. Each unit provides for forty-six beds, as 
follows : 

Two open wards of twenty beds each; two separation rooms of two beds each; 
two separation rooms, one bed each. 



ing hospitals in or close to the large cities, where the 
cost of land usually makes an extended pavilion plan 
impracticable. 

It has been noted that in the Virchow unit the cen- 
tral portion, containing the service rooms, is two stories 
high. The total height of this central portion is not, 
however, much greater than that of the wings, since 
the service rooms are not as high as the wards (Fig. 
56). 



9 8 



ORIENTATION OF BUILDINGS 



The principle involved in this arrangement may be 
extended further (Fig. 57), resulting in what may be called 
the pyramidal type of ward construction, in which each 
story is less in area than the one below. Such buildings 
may be placed close together and yet have adequate sun- 
light, and all of the wards may have ridge ventilation. 



w 



w 



w 




Fig. 57.' — Diagrammatic section illustrating the "pyramidal" type of ward. 
The service portion is indicated by the letter S, and the wards proper by the 
letter W. B indicates the basement. It will be noted that all the wards can 
have ridge ventilation. The idea expressed by this diagram is worked out in 
practical form in the plan on the opposite page, in which the one story wings 
have been turned at right angles to the main structure, forming a U court. 



The diagrams and plans herein presented illustrate a ward 
unit of a pyramidal type designed by the author. Figs. 58, 
59, and 60 give the detailed plans of each floor, and the 
diagrams of Figs. 61, 62, and 63 show the building in iso- 
metric projection, with the shadows as they would be at 
the winter solstice. 

The general plan (Fig. 64) illustrates a method of group- 
ing these units to form a complete hospital. 

The basic idea of the pyramidal type of ward is to com- 
bine the economic advantages of the three-story building, 
and its adaptability to subdivision of patients, while re- 
taining the most valuable feature of the one-story type, 
namely, ridge ventilation. 



HOSPITALS 



99 




^~l£ 



Fig. 58. — Pyramidal type of ward unit. First-floor plan. A cross section of 
the one-story ward wings (W) is shown in Fig. 50. These wings are higher 
studded than the service portion. 



References. 

C. Connecting corridors. L. Lavatories, 0/-0" X i3'-o". S. Laboratory, 0/-9" 
X 12-0". L. R. Linen room, 12-0" X 12-6". K. Kitchen, 12-0" X 15-6". 
E. H. Entrance hall. EL. Elevator. B. R. Bath room, 0/-9" X 12-0". 
H. Hall. D. Day room, i 4 '-6"X25 / -6". W. Wards, 26'-o"X45'-o". T. Open- 
air terrace. R. Terraces between the pavilions. 



IOO 



ORIENTATION OF BUILDINGS 




Fig. 59. — Pyramidal type of ward unit. Second-floor plan. The wards (W) 
have ridge ventilation. They are higher studded than the service portion. 



References. 

W. Wards, 22'-o" X 32'-o". P. Private rooms, n'-o" X i2'-o" and o'-6" X 
i 2 '-o". K. Kitchen, i2'-o" X i6'-q". I. Linen room, 8-0" X 20-6". B. R. 
Bath room, 7-0" X i2'-o". T. Patient's toilet room, 4-0" X 8'-o". L. Lavatory, 
8'-o" X 15-6". H. Hall. F. Fire escape stairway. 



HOSPITALS 



IOI 




Fig. 60. — Pyramidal type of ward unit. Third-floor plan. The ward (W) 
has ridge ventilation and extends up to the roof, as does also the open-air 
ward, S. B. 

References. 

W. Ward, io'-o" X 19-0". K. Kitchen, io'-o" X n'-o". T. Patient's toilet 
room, 4'-o" X 8'-o". L. Linen room, 8'-o" X 15-6". H. Hall. S. B. Open- 
air ward. F. Fire escape stairway. 



102 



ORIENTATION OF BUILDINGS 



The height from floor to ceiling of an open ward should 
never be less than twelve feet and is often made more 
than this, and in wards of the type shown in Fig. 50 it is 
necessarily much greater. Assuming thirteen feet in the 




Fig. 61. — Pyramidal type of ward unit. Shadow diagram 10 a.m., winter 
solstice, Lat. 42°-o' N. 



clear or fourteen feet from floor to floor, for wards with 
flat ceilings, as a fair average, we should have in a three- 
story pavilion, as customarily planned, a height of forty- 
one feet from the first-floor level to the ceiling of the third 

floor. 



HOSPITALS 103 



If, however, we adopt what I have called the Virchow 
idea, of building the second story over the service portion 
of the first, and the third story over the service portion of 
the second, at the same time reducing the height of the 




Fig. 62. — Pyramidal type of ward unit. Shadow diagram 12 M., winter 
solstice, Lat. 42°-o' N. 

service rooms to nine feet in the clear, which is ample, we 
shall obtain as the height of the three-story portion of our 
building, from the first-floor level to the ceiling of the third 
floor, thirty- three feet, — a saving of eight feet over the cus- 
tomary construction. 



104 ORIENTATION OF BUILDINGS 

This reduction in height, combined with the successive re- 
duction in area of each story, makes it possible to place the 
buildings at the minimum distance apart. In the plan (Fig. 
64) the distance between adjacent pavilions is thirty-six feet, 




FlG. 63. — Pyramidal type of ward unit. Shadow diagram 2 p.m., winter 
solstice, Lat. 42°-o' N. 

and the shadow diagrams (Figs. 61, 62, and 63) demonstrate 
that this distance, with the orientation adopted, is ample to 
secure adequate sunlight, even at the winter solstice. 

And thus the first requirement of our program is satis- 
fied, that the distance between adjacent pavilions should 



HOSPITALS 105 

be reduced to the minimum consistent with adequate light 
and air. 

Referring to the general plan (Fig. 64), it will be seen 
that between the two groups of pavilions extends an open 
space of ample dimensions, — one hundred feet wide, and 
something over six hundred feet long. This is the Mittel 
Allee of our hospital. Its general level is several feet 
above that of the rest of the grounds, and its vista is 
closed at one end by the Administration Building, a low 
one-story structure, and at the other by the Chapel. Be- 
tween the first group of pavilions and the street is also a 
wide, open space, but at a lower level than the other. 

And thus the second requirement of our program is met, 
that there should be adjacent to the pavilions, but not 
between them, large areas of open ground easily accessible 
to the patients. 

Each of the pavilions provides for forty-five beds, dis- 
posed as follows, in wards of various sizes, aspects, and 
conditions: On the first floor two open wards of ten beds 
each; on the second floor two open wards of six beds each, 
and three single rooms; and on the third floor one open 
ward of four beds and an open-air ward of six beds. 

And thus the third requirement of our program is met, 
that the pavilion should provide for a proper subdivision 
of the patients. 

The two open wards on the first floor are of the arched 
section shown in Fig. 50 and provided with ridge ventila- 
tion. The two open wards on the second floor have slop- 
ing ceilings following the slope of the roof, and are also 
provided with ridge ventilation. The ward on the third 




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108 ORIENTATION OF BUILDINGS 

floor is open to the roof, and is also provided with ridge 
ventilation. 

And thus the fourth requirement of our program is met, 
that all of the wards should have ridge ventilation. 

The patients on the first floor have access to the ter- 
races (T and R), which are at the same level as the floor of 
the wards and overlook the Mittel Allee, which is reached 
by a gentle incline from the terraces (R) between the 
pavilions. The roof of the connecting corridors is con- 
structed to serve as a terrace for the patients on the second 
floor, while the patients on the third floor have the open- 
air balcony or loggia (SB, Fig. 60). 

And thus the fifth requirement of our program is met, 
that facilities for out-of-door treatment should be provided. 

The roof of the Hydrotherapeutic Building is designed to 
be flat, and arranged as a roof garden, affording facilities 
for the true sun bath, in which the unclothed body is 
exposed directly to the sun's rays. 

The general plan (Fig. 64) is designed to illustrate the 
adaptability of the pyramidal type of ward unit to a lot 
of comparatively restricted dimensions. It consists of a 
series of U courts facing southwest; and the high buildings 
of the service and administration groups, disposed in the 
same general shape, are so placed as not to interfere with 
the sunlight for the ward pavilions. The entrance court 
yard (E) and the service court yard (S) are at the level 
of the surrounding streets, and are reached by arched 
entrances at the basement level; the main entrance 
through the out-patient block (0-0) and the service 
entrance through the service block (D-L). The main 



HOSPITALS 109 



floor level of the buildings is one story above the level of 
the entrance court yards. All of the buildings have direct 
sunlight on all of their exterior walls at some time of day 
throughout the year, with the exception of one, in which 
there is a small area of complete shadow. This, in the 
light of previous discussions, the reader should easily be 
able to discover — and suggest a remedy. 

It will be noted in this hospital plan that the direction 
of the streets has enabled us to adopt the best possible 
orientation for the buildings. If the streets enclosing our 
hospital lot had been laid out north and south, east and 
west, it would have been a difficult matter to work out a 
satisfactory plan. 

In the next chapter we shall point out the principles 
which should govern the laying out of streets. 



CHAPTER IV 
Streets 

In the study of streets there are two matters to be con- 
sidered; sunlight and sky light. Sky light comes from 
all directions of the heavens; sunlight from only one direc- 
tion, constantly varying with the revolution of the sphere. 
The direction or orientation of the street affects the sun- 
light particularly: the height of the buildings bordering 
upon it affects both. 

To investigate the distribution of sunlight in streets we 
shall employ a method similar to that used in obtaining 
the shadow curves of the cube, and to simplify the problem 
the buildings on either side will be assumed to be built in 
blocks of uniform height, extending continuously in both 
directions. 

Fig. 66 is the cross section of such a street running north 
and south; Fig. 67 a similar street running southeast and 
northwest, and Fig. 68 a similar street running east and 
west. 

The full lines give the angle of inclination of the plane of 
the sun's rays at the period of the equinoxes, and since at 
this period of the year the sun's rays fall in the same plane 
throughout the day, the cross section of the east and west 
street, being at right angles with this plane, shows the same 
inclination for every hour. 

The distribution of the sunlight may also be shown by 



STREETS 



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ORIENTATION OF BUILDINGS 






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ORIENTATION OF BUILDINGS 



sunlight curves. The method of obtaining these curves is 
shown in Fig. 69. 

This is a cross section of a street running southeast- 
northwest, taken looking northwest. 



(. t fre_Sun ^ 




Fig. 69. — Cross section of street running southeast and northwest, looking 
northwest. The angles of sunlight are shown as they would be at the summer 
solstice. Lat. 42°-o' N. 



The dotted lines represent the plane of the sun's rays 
at the hours noted. It is clear that the point of inter- 
section of these lines first comes into sunlight at 9 a.m., 
remaining in sunlight until 5 P.M., a period of eight 
hours. 



STREETS 115 

By finding a series of such points and connecting them, 
we shall obtain the curve shown, each point of which is in 
sunlight for eight hours, and may, therefore, be called the 
"eight-hour curve." 

It is in this way that the following series of diagrams 
have been drawn (Fig. 70). 

These diagrams give the complete series of sunlight 
curves at the typical seasons of the year, for streets run- 
ning north-south, east-west, and at an angle of 45 with 
the meridian. 

In these diagrams the height of the buildings is rep- 
resented as one and one-half times the width of the 
street. 

The diagrams show a great difference in the amount of 
sunlight received. 

In the north-south street the distribution is symmetrical, 
the buildings on either side receiving an equal amount. 

In the. east-west street the surface of the street receives 
no sunlight at all during six months of the year, and the 
buildings on the south side of the street are in perpetual 
shadow during the same period. 

In city planning the east-west street should be avoided 
as far as possible, and where unavoidable the buildings, 
especially on the south side, should be of moderate height, 
and built in detached blocks, so as to admit the sunlight 
between them. 

When streets are laid out at right angles to each other 
according to the "checkerboard" plan, the best distribution 
of sunlight is obtained when one series of streets runs north- 
east-southwest and the other riorthwest-southeast. 



n6 



ORIENTATION OF BUILDINGS 






^ 




Fig. 70. — Sunlight curves in streets. Ihe three upper diagrams are for a 
street running north and south, the three middle diagrams for a street running 
east and west, and the three lower diagrams for a street running at an angle of 
45 degrees with the meridian. The diagrams of the left-hand column are drawn 
for the winter solstice; of the center column for the vernal and autumnal equinox; 
and of the right-hand column for the summer solstice. , The zones between the 
curves are shaded in a series of tints, the lightest zone being in sunlight between 
eight and nine hours, and the solid black being without sunlight. 



STREETS 117 

This arrangement was recommended many years ago by 
Horace Bushnell. 

In his essay on City Plans 1 occurs the following passage: 

"It is also a great question, as respects the health of the 
city, in what direction, or according to what points of the 
compass, the streets are to be laid. To most persons it 
will appear to be a kind of law that the city should stand 
square with the cardinal points of the compass, — north 
and south, east and west. And where this law appears 
not to have been regarded, how many will deplore so great 
an oversight, and even have it as the standing regret of 
their criticism. Whereas, in the true economy of health 
and comfort, no single house or city should ever stand 
thus, squared by the four cardinal points, if it can be 
avoided. On the contrary, it should have its lines of 
frontage northeast and southwest, northwest and south- 
east, where such a disposition can be made without injury 
in some other respect; that so the sun may strike every 
side of exposure every day in the year, to dry it when wet 
by storms, to keep off the mould and moss that are likely 
to collect on it, and remove the dank sepulchral smell that 
so often makes the tenements of cities both uncomfortable 
and poisonous to health." 

It is unfortunate that in so many cases where the 
"checkerboard" plan has been adopted, the streets have 
been laid out north-south and east-west, which is the 
worst arrangement possible. 

The effect of tall buildings in cutting off sunlight and 
sky light from buildings on the opposite side of the street, 

1 Work and Play, Horace Bushnell, N.Y., Charles Scribner, 1864. 



Il8 ORIENTATION OF BUILDINGS 

and from the street itself, is considerable, and in the 
building laws of most European cities a definite relation 
has been established between the width of the streets and 
the height of the buildings which may be built upon them. 

An admirable example of such a regulation is found in 
the building laws of Paris, in which the matter is worked 
out with a precision and completeness well worthy of 
study. 1 

The accompanying diagram (Fig. 7.1) illustrates its appli- 
cation to a street 16 meters (52.48 feet) in width. 

The main structure of the building must be built within 
the limits of the heavy enclosing line, which is determined 
as follows: 

The height of the vertical AA is taken at 6 meters plus 
the width of the street, for streets less than 12 meters in 
width, and for streets over that width it is taken at 18 
meters, plus one-quarter of the amount by which the width 
of the street exceeds 12 meters, but must not exceed 20 
meters (65.60 feet) in any event. For a street of 16 meters 
the height AA will, therefore, be 19 meters (63.32 feet). 

From the top of this line a circular arc is drawn, and 
tangent to it a line of 45 inclination. This tangent is 
extended until it meets a vertical halfway back in the 
building or until it meets a similar tangent determined by 
the frontage of the rear portion of the building. 

The radius of this arc is taken at one-half the width of 
the street, but may not exceed 10 meters (32.80 feet) in 
any event. 

A similar regulation governs the rear facade of the build- 

1 The Paris law is given in full in Appendix B, 



STREETS 



IIQ 



ing and also all frontages on light courts and areas, the 
result being an abundance of light and air throughout the 
structure. 





Fig. 71. — Diagram illustrating the building regulations of Paris, applying to 
the height of buildings. The vertical A-A and the radius of the circular arc vary 
with the width of the street. The horizontal B-B marks the limit of height for 
party walls, and the vertical line above the curve and just back of the front wall 
line, marks the setback for chimneys. The lighter enclosing lines beyond the 
heavy line mark the limit of projection for balconies, cornices, and other projec- 
tions from the main structure. 

In England the matter is regulated in two ways: directly, 
by building by-laws limiting height, varying in different 
cities and for different classes of buildings; and indirectly, 



120 ORIENTATION OF BUILDINGS 

by the statute law of ancient lights. Under this law an 
owner or tenant of a building may acquire a right to light 
coming across the property of another, just as in this country 
a right of way across the land of another may be acquired 
by prescription. 

"Cujus est solum ejus est usque ad ccelum" is an ancient 
maxim of our common law, and in the words of an English 
writer, "An interference with the space superincumbent 
on a man's land is an injury for which the law provides 
a remedy." 

In England the deprivation of light is regarded as such 
an interference, actionable at law, but in this country the 
individual owner, where not restrained by specific statutes, 
is allowed to build as high as he pleases, regardless of the 
injury done to his neighbors and to the public, and even 
the right of a municipality to impose a limit to the height 
of buildings has been contested. 

A recent decision (May 17, 1909) of the Supreme Court, 1 
however, upholds the constitutionality of such building 
laws, and even that city which has taken a mistaken pride 
in having originated the "skyscraper" type of architecture 
has recently imposed a maximum limit of 210 feet to the 
height of its buildings. 

In my own city of Boston a law has been in force since 
1892 limiting the height of buildings generally to two and 
one-half times the width of the street, with a maximum 
limit of 125 feet; and subsequent legislation has reduced 
this limit in certain districts of the city. 

1 Welch vs. Board of Appeal of the City of Boston. U. S. Reports, Vol. CCXIV, 
page 91. 



STREETS 121 

The regulations of some other American cities in this 
regard are given in Appendix C. 

The method of limiting the height of buildings by a 
horizontal plane, either at a fixed height, or at a height 
proportional to the width of the street, is simple in appli- 
cation but is not scientific, since it assumes that what is 
the proper height for the front wall or facade is also the 
proper height for the rear portions of the building; whereas, 
as a matter of fact, the rear portions may well be allowed 
to rise to a greater height, in proportion to their distance 
back from the street line. 

This method also results in an uninteresting and hard 
type of architecture. The land owner, intent on securing 
every foot of rentable space, duplicates one story on top 
of another, with the usual result that the cornice is forced 
above the level of the real roof as shown in Fig. 72, cutting 
off the sunlight and darkening the street unnecessarily. 

This false position of the cornice constitutes the dis- 
tinguishing mark of ordinary American civic architecture, 
and is the direct result of unscientific building laws. 

Although a building law designed solely for the purpose 
of securing an aesthetic effect would probably be decided 
to be unconstitutional in this country, it fortunately hap- 
pens that in the matter of regulating the height of build- 
ings, that method which naturally results from a scientific 
study of the question of sunlight also tends to produce the 
best type of architecture. 

A method which has been proposed by several architects, 
and which has also been advocated by the writer, is illus- 
trated in Fig. 73. 



122 



ORIENTATION OF BUILDINGS 



Under this plan the height of the building is limited by 
a slanting line drawn from the opposite side of the street 
at a certain angle. This angle should be, in the opinion 




Fig. 72. — This type of cornice is typical of x\merican commercial architecture. 
It is not really a cornice but a distorted parapet wall, and is also bad from the 
practical point of view because it cuts off the sunlight unnecessarily. It is the 
direct result of unscientific building laws, which apply the limit of height to the 
highest point of the roof, often several feet below the top of the exterior walls of 
the building. 



of the writer, such that the height of the front wall of the 
building should not exceed one and one-quarter times the 
width of the street, and it is so shown in the diagram. 



STREETS 



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124 



ORIENTATION OF BUILDINGS 



In addition to the slanting line the extreme height of the 
roof is limited by a horizontal plane at a height uniform 
for all buildings, irrespective of the width of the street. 





Fig. 74. — The skyscraper and the street. The left-hand diagram is a cross 
section of a street bordered by buildings of reasonable height; the right-hand 
diagram a street with a wall of sky scrapers on either side. The street is supposed 
to run east and west and the shadows show the angle of sunlight throughout the 
day, at the vernal and autumnal equinox. Lat. 42°-o' N. 



A similar method may well be adopted to regulate the 
walls of the building fronting on light courts and areas, and 
for this purpose an angle of less inclination from the vertical 
may be justified. 

In discussing the question as to what should be the limit 
of height of buildings in cities it is proper to assume that 
both sides of the street will in time be built up to whatever 
limit is decided upon. The effect of a few scattered tall 



STREETS 125 

buildings in darkening the streets is not serious, but the 
effect of a solid wall of skyscrapers would be extremely so. 
In the accompanying diagrams (Fig. 74) is shown the 
section of a street 60 feet wide, in the one case bordered 
with buildings 250 feet high and in the other with buildings 
regulated in accordance with the building law proposed by 
the author. Which of the two should be typical of the 
American city planning of the twentieth century is left to 
the judgment of the reader. 



APPENDIX A 



Sun Tables 





Winter Solstice. 


Equinoxes. 


Summer Solstice. 


Hour angle. 


Az. 


Alt. 


Az. 


Alt. 


Az. 


Alt. 


120° 










127 42' 


i° 21' 


I05 ° 










Il6° 4' 


9° 3o' 


90° 






90 0' 


o° 0' 


105° 7' 


18 7' 


75° 






78 10' 


9° 23' 


94° 0' 


27 20' 


6o° 






65° 4l' 


18 5' 


82 2' 


36 ° 40' 


45° 


40 40' 


5° 14' 


51° 57' 


26 6' 


68° 10' 


45° 39' 


3°° 


27° 59' 


io° 25' 


36° 25' 


32° 36' 


So° 48' 


53° 43' 


iS° 


14 9' 


13° 48' 


18° 54' 


36° 58' 


28 2' 


59° 4o' 


o° 


o° 0' 


15° 3' 


o° 0' 


38° 30' 


o° 0' 


6i° 57' 



Sunrise and Sunset 



3h. 


48 m. 


5o° 16' 


o° 0' 










6h. 


m. 






90 0' 


o° 0' 






8h. 


12 m. 










129° 44' 


o° 0' 



London. Lat. 51 30' N. 



126 



APPENDIX A 



127 





Winter Solstice. 


Equinoxes. 


Summer Solstice. 


Hour angle. 


Az. 


Alt. 


Az. 


Alt. 


Az. 


Alt. 


90° 






9 o° 0' 


o° 0' 


«o° 35' 


11° 27' 


75° 


62 ° 24' 


o° 22' 


82 22' 


12° 57' 


104 18' 


23° 52' 


6o° 


54° 9' 


ii° 20' 


73° 54' 


25° 39' 


98 16' 


36 36' 


45° 


44° 7' 


21° 16' 


63 ° 26' 


37° 46' 


9i° 47' 


49° 32' 


3o° 


3i° 44' 


29° 3' 


49° 6' 


48 ° 36' 


83° 27' 


62 30' 


15° 


16° 47' 


34° 4i' 


28 11' 


56° 47' 


67° 29' 


75° 6' 


o° 


o° 0' 


36° 33' 


o° 0' 


60° 0' 


o° 0' 


83° 27' 



Sunrise and Sunset 



5 h. 2m. 

6 h. o m. 
6 h. 58 m. 



62 38' 



90 



117" 22' 



New Orleans. Lat. 30 o' N. 



APPENDIX B 



DECREE REGULATING THE HEIGHT OF BUILDINGS AND 

PROJECTIONS FROM THE SAME IN THE CITY 

OF PARIS. August 13, 1902 

Article i. The limits beyond which buildings upon the public ways 
of Paris are not allowed to project is fixed: first: by two "limiting cross 
sections" established, one for the structure proper, and the other for pro- 
jections forming an integral part of the structure; second: by special rules 
set forth under Title II, Sections III and IV of this decree, for projections 
not forming an integral part of the structure. 

TITLE I 
HEIGHTS OF BUILDINGS 

First Section. Buildings on Public Ways 

Art. 2. The "limiting cross section" of the structure proper is deter- 
mined by a vertical line erected on the front line of the lot. 

The height of this line, measured from the sidewalk level or the level of 
the pavement at the foot of the facade and taken at the middle point of 
this facade, is calculated thus. 

For streets less than 12 meters (39.36 feet) in width, the height must not 
exceed 6 meters (19.68 feet) plus the width of the street. 

For streets of 12 meters and over this height must not exceed iS 
meters (58.64 feet) plus one-quarter of the amount by which the width of 
the street exceeds 12 meters, but must not in any case exceed 20 meters 
(65.60 feet). 

In calculating this height a fraction of a meter in the width of the street 
is taken at one meter. 

On sloping streets the facade of the buildings is divided into sections 
not exceeding 30 meters (98.40 feet) and the height of each section is taken 
in the middle. 

128 



APPENDIX B 129 



In the case of several distinct buildings the height of each is taken sepa- 
rately according to the above rules. 

Art. 3. The "limiting cross section" referred to in the preceding article 
is completed by a circular arc, tangent to the vertical line, at its highest 
point, and by another line tangent to this circular arc. 

The radius of the circular arc is taken at half the width of the street 
but must not exceed 10 meters (32.80 feet). However, for streets less 
than 12 meters (39.36 feet) it need not be reduced to less than 6 meters 
(19.68 feet). 

The other line referred to, tangent to this circular arc, is drawn with an 
inclination of 45 degrees until it meets a vertical erected in the middle of 
the depth of the building, taken at the ground floor level. 

However, it is allowed, if desired, to prolong this inclined line until it 
meets the tangent of another such circular arc established as described 
above on the highest point of the vertical line referred to in Article 10. 
The inclination of this second tangent must also be 45 degrees. 

In any case, excepting for chimney stacks, the highest point of party 
walls between two buildings must not be built more than one meter (3.28 
feet) above the horizontal tangent of the circular arc, excepting as provided 
in Article 6. 

Art. 4. At street intersections the "limiting cross section" is deter- 
mined according to the open space between the facades at such inter- 
sections, taken at right angles, and considered as the width of the street 
according to Article 2. But such additional height is allowed only for that 
portion of the facade which is opposite such open space. 

Nevertheless, every building built upon a corner of two streets of unequal 
width, whatever may be their level or slope, may be built upon the narrower 
street up to the height allowed for the wider of the two, provided that such 
additional height does not extend back on the narrower street for a distance 
greater than one and a half times its width. 

For buildings built upon a corner formed by two streets of equal width 
but of different slopes, the height is taken as the average for the middle 
points of each frontage. But frontages on which the height is taken con- 
formably to the level of the street on which such frontages face, as for 
separate buildings, need not be reckoned in determining such middle 
point. 



130 APPENDIX B 



Art. 5. For buildings comprised between streets of different widths 
or of different levels the "limiting cross section" for each facade must be 
determined by the street upon which it faces. 

However, if the extreme distance between two such facades does not 
exceed 15 meters (49.20 feet) the facade upon the narrower or lower street 
may be built up to the "limiting cross section" fixed for the facade upon the 
wider or higher street. 

Art. 6. Chimney stacks may not be built more than one meter (3.28 
feet) above the highest point of the "limiting cross section" and their 
front face must be at least one meter back of the front line. 

Art. 7. For portions of a building projecting beyond or built back of 
the general building line the "limiting cross section" referred to in Article 2 
is based upon a street width equal to the distance between the extreme 
projection of the facade and the street line opposite. 

In such calculations, fractions of a meter are taken as equal to a 
meter. 

Buildings or sections of buildings built at the ground story or on the 
stories above, back of the street fine, may be built within the "limiting 
cross section" permitted for a street the width of which is equal to the 
distance between the street line opposite such building or section of build- 
ing, provided that there is built on the street line a solid and substantial 
wall at least one meter high. 

Art. 8. Buildings which are not built up to the "limiting cross sec- 
tion" permitted may be constructed in all parts as the builder desires, 
provided they do not project beyond such "limiting cross section." 

Second Section. Buildings on Areas and Courts 

Art. 9. Courts which furnish light and air to rooms capable of being 
used for purposes of habitation, either in the daytime or at night, must 
have an area of 30 meters (322.80 square feet) at the least. 

For courts which only light such rooms as kitchens the minimum area 
may be reduced to 15 meters (161.40 square feet). 

Small courts or "light shafts" serving to give light and air to rooms 
which cannot be used for purposes of habitation must have an area of 
8 meters (86.08 square feet) at the least. 



APPENDIX B 



131 



Art. 10. The clear space opposite each window of a room serving for 
day or night habitation must not be less than is provided in the following 
table. 



Minimum Area of 
Court. 


Clear Space. 


Minimum Area of 
Court. 


Clear Space. 


Square Feet. 
322.80 
358.63 
394.46 
430.40 
466. 23 


Feet. 
13.12 
14. 20 
15.28 
16.40 
17.48 


Square Feet. 
502 . 06 
538.00 

573.83 
609.66 


Feet. 
18.56 
19.68 
20.76 

21 .84 



For buildings opposite party walls the minimum clear space opposite 
windows of habitable rooms is 5 meters (16.40 feet). 

The "limiting cross section" of buildings or parts of buildings situated 
on courts, composed of the same elements as indicated in Articles 2 and 3, 
is determined by the following table. 



Minimum Clear Space. 


Maximum Height of 
Vertical. 


Maximum Radius 
of Arc. 


Square Feet. 


Feet. 


Feet. 


13.12 


39 36 


19.68 


14. 20 


42.64 


21.32 


15.28 


45-92 


22 .96 


16.40 


49. 20 


24.60 


17.48 


52.48 


26. 24 


18.56 


55-76 


27.88 


19.68 


59-04 


29.52 


20.76 


62.32 


31.16 


21 .84 


65.60 


32.28 



Buildings or parts of buildings built in retreating stories may be built 
in each story according to the "limiting cross section" determined sepa- 
rately for that story according to the clear space opposite that story. 

The ground level of every court is considered independently of that 
of the public street or of another court. 

Stairway towers or bays arranged in such courts may project beyond 
the "limiting cross section" as above determined up to the ceiling level of 
the highest story served by such stairway. 



132 



APPENDIX B 



Art. ii. In the case of courts which only furnish light and air to such 
habitable rooms as kitchens, the dimensions of the "limiting cross section" 
may be modified as per the following table. 



Minimum Area of 


Minimum Clear 


Maximum Height of 


Maximum Radius 


Court. 


Space. 


Vertical. 


of Arc. 


Square Feet. 


Feet. 


Feet. 


Feet. 


. 161 .40 


6.56 


39 -3 6 


19.68 


179. 26 


7.08 


42.64 


21.32 


197.23 


7.64 


45-92 


22 .96 


215 . 20 


8.20 


49.20 


24.60 


233.06 


8.76 


52.48 


26.24 


251-03 


9.28 


55-76 


27.88 


269 . OO 


9.84 


59-04 


29.52 


286.86 


IO.36 


62 .32 


31.16 


3 4.83 


IO.92 


65.60 


32.28 



Art. 12. The vertical walls of "light shafts" may be built to the 
height determined for the building in general. 

The clear space opposite windows in "light shafts" must not be less than 
1 m. 90 (5.33 feet). 

Kitchens of the concierge on the ground floor may take their light and 
air from "light shafts." 

On the top story of buildings habitable rooms may take their light and 
air from "light shafts." 

Art. 13. In any case the minimum area of light courts and shafts as 
determined by Article 9 may not be diminished by new construction or 
selling of property. 

Art. 14. Glass roofs may not be built over light courts or shafts above 
the rooms which take their light and air from them, whether rooms of habi- 
tation, kitchens or water closets, unless such glass roofs have monitor 
ventilating sash with a clear opening of at least one-third the area of the 
court and of a minimum height of 40 centimeters (15.72 inches), and unless 
also there are arranged at the bottom of such court or shaft openings com- 
municating with the cellar or basement having at least 8 decimeters (8.56 
square feet) of area. The monitor ventilation is not required for light 
wells and shafts unless they serve habitable rooms, kitchens, or water 
closets; but light shafts, the lower part of which does not communicate 
with the outer air, must be ventilated. 



APPENDIX B 133 



Art. 15. All measurements of light courts and shafts must be taken 
on the work. 

Art. 16. Owners of adjoining buildings who may have made an agree- 
ment to have light courts and shafts in common may build them of the 
dimensions prescribed in Articles 9, 10, 11, and 12 for light courts and shafts 
belonging to a single building. 

They must, in such case, notify the prefect of the Seine of their agree- 
ment and execute with the City of Paris, before commencing the work, an 
agreement to maintain such courts and shafts for their common use. 

Such courts and shafts may be divided by walls of a height in accordance 
with article 663 of the civil code. 

Third Section. Story Heights 

Art. 17. In all buildings bordering on public ways, private ways or 
courts, the height of the ground story and that of the next above must 
never be less than 2 m. 80 (9.18 feet) in the clear. 

The height of basements and other stories must never be less than 2 m. 60 
(8.53 feet) in the clear. 

For the top story of a building this last height applies to the highest 
part of a sloping ceiling, and every room with a sloping ceiling in part must 
have at least 2 square meters (21.52 square feet) of level ceiling. 



TITLE n 
PROJECTIONS FROM BUILDINGS 

First Section. In General 

Art. 18. No projection may be built from any building in Paris, 
whether on the street line or not, so as to project over a public way, other 
than those authorized below. 

Art. 19. For buildings on the street line, the front face of party walls 
must always mark the street line: for this purpose there must be reserved, 
at a height of a meter and a half above the ground, a level surface at least 
20 centimeters square. 

Art. 20. Dimensions of projections are fixed (saving the exceptions 
given below) according to the width of the street opposite the building if 



134 APPENDIX B 



on the street line, and according to the effective width for buildings set 
back. 

All projections are measured from the street line for buildings upon the 
street line and from the ashlar line for buildings not on the street line. 

In Reckoning such width, fractions of a meter are taken as one meter. 

Second Section. Projections of Constructions Forming a Part of 
the Building Proper 

Art. 21. The limit of projections from the facade, for decorative 
features, foundations, balconies and built-out constructions, is determined 
by a "limiting cross section" established as follows: 

This "limiting cross section" is composed of two vertical lines, one 
relating to the upper part of the facade from a point taken at the estab- 
lished height as determined in Article 2, and the other relating to the lower 
part of the facade. 

The line separating these two parts, for streets of 30 meters (98.40 feet) 
and over is placed at a minimum height above the sidewalk of 3 meters 
(9.84 feet), and for streets less than 30 meters, at a height of 6 meters 
(19.68 feet) less one-tenth of the width of the street, above the sidewalk. 

The projection of the "limiting cross section" from the street line is for 
the upper part of the facade 8 centimeters for every meter in the width 
of the streets up to streets of 10 meters in width, and 60 centimeters plus 
ihs of the width of the street, with a maximum of 1 m. 20 (3.94 feet) 
for streets of 10 meters and over. 

The projection of the "limiting cross section" for the lower part of the 
facade must not exceed one-quarter of the projection of the upper part, 
but need not be less than 20 centimeters (7.8 inches) in any event. 

For the upper part of the facade, the plane of the street line must serve 
as the basis of all decoration and occupy, at each story, one-tenth at least 
of the surface of the facade of that story, after deducting bays. 

Art. 22. There may be established upon the upper part of facades, 
constructions corbeled out, whose gross area, projected on a vertical plane 
parallel to the facade, may not occupy in any case, more than one-third 
of the total upper part of said facade. 

For buildings having several facades upon the street, each facade shall 
be considered separately in such calculation. 



APPENDIX B 



*35 



Each dividing section counts with either one of the facades which it 

separates, at the choice of the constructor. 

Laterally, and at the ends of buildings, the projections of the construc- 
tions are limited by a vertical plane forming an angle of 45 degrees with 
the front wall and intersecting it at 25 centimeters (9.8 inches) from the 
party line. 

Art. 23. In streets of 16 meters (52.48 feet) of width and over, the 
established projection of every balcony may be increased one-quarter, 
provided that in horizontal projection the total of all balconies does not 
cover more than a quarter of the surface permitted at each story. 

Art. 24. Notwithstanding Article 21, the decoration of the principal 
entrances of a building and that of the cornices of the ground story may 
descend to a height of 2 m. 50 (8.20 feet) above the sidewalk, with a 
projection equal to twice that permitted for the lower part of the facade. 

In streets of 20 meters and over, the decoration of the principal entrances 
may descend to the ground, with a projection not over twice that per- 
mitted for the lower part of the facade. 

Art. 25. Iron guards and other similar objects of iron- work intended to 
serve as defences on balconies may have 25 centimeters (9.8 inches) in 
excess of the projection allowed for the cornices, balconies and entablatures 
upon which they are fixed. 

Art. 26. Roof ornaments, such as finials on dormers, open crestings 
and galleries, may not project beyond the arc of a circle concentric with 
that of the "limiting cross section" and of which the radius exceeds that 
of the latter by the permitted projection of the upper part of the facade. 

In their total, the size of the crowning members of dormers may not 
exceed two-thirds of the frontage of the facade of the building, after de- 
ducting the crowning members of the corbeled-out structures projecting 
over the public way, as provided for in this decree. 

For the crowning members of the corbeled-out constructions, the in- 
crease of radius referred to above, may equal twice the maximum projec- 
tion permitted for the upper part of the facades, provided that spaces of 
habitable rooms do not exceed the limits of the concentric arc referred 
to above. 

In the three above cases, the circular arcs are prolonged by their tangents 
at 45 degrees. 



136 APPENDIX B 



For corbeled-out constructions those portions of the crowning members 
which project above the established line of the roof may not exceed in width 
one-third of the portion on the facade proper. 

■y 
Third Section. Projection of Objects not Forming an Integral 

Part of the Structure 

(This section consists of ten articles and deals with store fronts, grilles, 
signs, marquises, lights, rain-water conductors, etc.) 

Fourth Section 
(This contains one article, dealing with temporary structures.) 

TITLE HI 
SPECIAL REQUIREMENTS 

(This contains seven articles, dealing with special cases, two of which 
are of sufficient interest to be given in full.) 

Art. 38. Existing projections beyond the limits fixed by the present 
decree may not be repaired even in part, or restored, except within the 
limits established herein. 

Except that in certain cases, ancient objects of archeological or artistic 
interest, may be repaired by permission of the prefect of Seine. 

Art. 42. The prefect of the Seine may, in the case of private con- 
structions having a monumental character, or for purposes of art, science, 
or industry and with the approval of the "conseil general des batiments 
civils" and the minister of the Interior, authorize exceptions from the 
present decree relative to the height of buildings. 

He may also, following the same procedure, authorize exceptional pro- 
jections for buildings having a monumental character. 

Art. 44. The decrees of July 22, 1882, and July 23, 1884, are repealed. 



APPENDIX C 



REGULATIONS OF SOME OF THE PRINCIPAL CITIES OF THE 

UNITED STATES AND CANADA GOVERNING THE 

HEIGHT OF BUILDINGS 

Note. — The regulations given are those which apply to buildings of 
fireproof construction. Limitations of height for non-fireproof buildings 
primarily imposed to decrease the fire hazard, rather than to prevent en- 
croachments upon the light and air of the public streets, are not included 
in this list. 

All of the regulations given are those in force in 1911. 

Boston. — Since 1891 the height of buildings in all cities of Massachu- 
setts has been limited to 125 feet. 

Grain elevators, coal elevators, and sugar refineries are excepted, and 
steeples, domes, towers and cupolas are not included within the 125 feet 
limit. 

In Boston this limit of height is subject to a further restriction of 2§ 
times the width of the street, so that on streets of less than fifty feet in 
width the height must be less than 125 feet. 

The maximum height of 125 feet is furthermore only permitted in those 
portions of the city in which the greater part of the buildings are used for 
business or commercial purposes. The boundaries of these portions have 
been determined by a commission appointed for the purpose and the areas 
within them are known as "District A." 

The remainder of the city, comprising much the larger part of its area, 
is known as "District B" and within this district the limitations of height 
are as follows: 

On streets of 64 feet in width, or less, the limit is 80 feet. 

On streets exceeding 64 feet in width the height may be equal to 1 \ times 
the width of the street but may not exceed 100 feet. Furthermore a 

137 



138 APPEXDIX C 



height of 80 feet may not be exceeded unless the width of the building on 
each and every public street on which it stands is at least one-half its 
height. 

In addition to these general regulations there are other special restric- 
tions, as follows: 

On certain streets in the vicinity of the state capitol the limit of height 
is 70 feet. Upon a portion of Commonwealth Avenue (one of the prin- 
cipal parkways of the city) the limit of height is 70 feet. 

This latter restriction is imposed by the Park Commissioners, who have 
the power to impose such restrictions on any parkway, boulevard or public 
way bordering on a park, within the city. 

Winnipeg. — Xot exceeding 120 feet. 

Montreal. — Xot exceeding 130 feet nor over ten stories. 

Portland. — Xot exceeding 160 feet nor over ten stories. 

Baltimore. — Xot exceeding 175 feet, except by special permission of the 
City Council. 

Cleveland. — Xot exceeding 200 feet, nor more than i\ times the width 
of the street nor more than five times the width of the base. 

Chicago. — Xot exceeding 260 feet. (After July n, 1911, not exceeding 
210 feet.) 

St. Louis. — The limit of height for all buildings other than hotels and 
office buildings is 2§ times the width of the street, with a maximum limit 
of 150 feet. 

The limit of height for hotels is 206 feet. 

The maximum limit of height for office buildings is 250 feet, but this 
height is not permitted unless the building covers at least one-half of the 
city block in which it is built, has frontages on at least three different 
streets, and fulfills certain stringent requirements in regard to fire protec- 
tion. Otherwise the limit of height for office buildings is the same as that 
for hotels, viz., 206 feet. 

St. Paul. — Xot exceeding 250 feet nor over twenty stories. 

Toronto. — Xot over five times the least horizontal dimension of the 
building. 

Seattle. — Xot over five times the least dimension of the base. 

Indianapolis. — Xo limit, except in the neighborhood of the city monu- 
ment, where a limit of 86 feet is imposed. 



APPENDIX C 139 



Cincinnati. — No limit. 
Detroit. — No limit. 
Hartford. — No limit. 
Milwaukee. — No limit. 
Minneapolis. — No limit. 
New York. — No limit. 
Philadelphia. — No limit. 



COLUMBIA UNIVERSITY LIBRARY 

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