Ratio of Window Area to Floor Area of Buildings,

Transcription

1 THESIS. Ratio of Window Area to Floor Area of Buildings, FRANPC WL.BROWN. F o r bl)e Decree B. S., School oj^ Arcl)itlect!ure. UNIVERSITY OF ILLINOIS, 1893.

2 Ratio of Window Area to Floor Area of Buildings. In selecting this subject I entered upon what v/as supposed to be almost an unexplored fie ld. Put in my course of reading on the subject of light in general, it was found that the subject had been somewhat previously considered to some extent by writers to be mentioned later. The quantity of light entering a room w ill evidently not depend entirely upon the size of the window but also upon its locat, ion. For example a window opening upon a porch does not * admit as much light as one otherwise situated. A building may farther be in close proximity to a much larger structure and although this obstruction does not completely prevent the admission of Tight it is thereby considerably lessened. Therefore the problem for solution is to find the minimum quantity of light suitable for ordinary cases which cannot be reduced without danger of injury to the eyes; although the more common error is found to be the admission of too much light rather than too l i t t l e.

3 The problem might alsn be considered from a hygienic standpoint bat this hardly fa lls within the province of the practical architect. Especially injurious to the eye is the diffused light reflected from brightly colored surfaces and which should be avoided or neutralized. The Intensity of Light varies the degree of illumination not always depending upon the area of the window surface but also upon its distance and farther upon the angle of incidence of the ligh t rays; referring to treatises on Physics we find that the degree of illumination varies inversely as the square of the distance and directly as the sine of the angle of incidence o; the ligh t rays. Light may enter a room by one of three ways. 1st. Through an opening in a vertical wall or an ordinary window. 2nd. Through an opening in a ceilin g or sky-light. 3rd. Through windows forming a combination of these kinds as dormer windows, photographic windows etc. It has been found that the greatest quantity of ligh t is admitted when it comes through a horizontal ap era tare or sky light. The Partheon at Rome is considered to be one of the most

4 satisfactorily lighted buildings in the world. The entire interior is lighted by a horizontal opening in. the vertex of the dome about 27 feet in diameter. Now the area of the circle being about 572 sq.ft, it follows that each superficial foot of the area lights more than 3380 cu.ft. of capacity It is best for the light to be admitted upon not mo^e than two sides of an apartment and i f possible these two sides should be opposite each other except in school rooms, libraries, studies etc. In school rooms, now windows should be placed in front of the pupils. I f external appearance require this to be done they should be fille d with opaque curtains or screens. Whether sky lights or windows should be used is a question whose decision depends chiefly upon the intended use of the room. But in general sky-lights are preferable when they may be conveniently employed. A more nearly uniform illumination may be obtained by means of openings for admission of light situated as centrally as possible in the rooms illumination from above then being preferable to that from the side. Some of the disadvantages in the use of sky-lights are; 1st. The degree of illumination varies with the

5 change of the position of the sun which is also true in case of side lights but the difference is less marked. 2nd. Light coming from above requires a larger area of openinr where even double glazing is necessary or ground glass panels in the ceiling. 3rd. In the case of snow fa lls Ahe snow is apt to accumulate anon the sky-lights thus preventing the admission of light until it is removed. Dust likewise collects on the glass and loses its transparency. 4th. It is much more d iffic u lt to make sky-lights water-tight than ordinary windows and repairs are more d if fic u lt. During the coarse of my reading some data has been collected which may be of service in designing openings for the admission of ligh t. The loss of light for different kinds of glass is as follov/s: - Ordinary G1. si s s Double Thick 9-13 Green or Red Orange 34 Out Glass 30-60

6 The following rules were found, referred to in the preceding data. Sir William Chambers states his rule thus; " I have generally added the depth to the width of the room and taken l/8th part of this sum as the width of the window." Assuming a building to be free from obstructions by high buildings in the neighborhood, one superficial foot of glass surface w ill be sufficient for inn cu.ft. of capacity of room centrally located in the wall of a square ^oom. Robert Morris' Rule. Multiply the length and breadth of the room together and this product by the length; and the square root of the last product ( i.e. of the capacity of room) w ill be the area of glass in the windows. The following rules were found in a German Work. In most cases the total window area should be from l/7 to l/5 the floor area. Providing the illumination is not obstructed by adjacent buildings. Hoping to deduce some general rules which mirfit be applied to American practice; A number of plans by Ameri can Architects have been taken and the relations exist 1 ng

7 between the window areas and the floor areas have been determined with the following results. Pheifer's American Mansions. Design - A. A.of W. Window area Room Area of R Win.Area A.» R. % Parlor 220 sq.ft. 45 5/6 sq.ft 45 5/6 220 Ploor area - 21 % Dining Room 218 2/3 29 5/9 29 5/ /3 Kitchen 194 2/ /9-14# jl 18 1/2 % Bed Room 255 l/:2 29 7/9 29 7/9 255 l/2 Z_ 12 % Design D. Room. A. of R. A. of W. A. of W. A. of R. Parlor 249 3/4 60 1/3 60 l/ /4 Din.Room Kitchen /3 26 2/3 168 B.R B.R l/3 41 l/ X l/

8 Design K Room. A. of R. A. of W. A. of V.r. % A. of R. Parlor Din.R ll/ l Kitchen 16 2 l/2 29 l/6 29 l/6 162 l/ Ch amb e r 137 l/ Chamber l/3 21 l/ Chamber Design H. Parlor Din.R

9 \ # v General Summary of Pheifer's Houses. Design. Parlor. Din.R. Kitcteen B.R. A. 21 % 14 % 18 l/2 X 12 X 10 D K H Average /4 % 16 % 17 % 15 % 22 l/4 { 16 j General Average l/2 X ~ Or Window Area About l/6 flo or area. A Series of Plans taken from a work by Loring 3z Jenney. Design 0. Room. A. of R. A. of W. A. of W. A. 8f R. Window area X Ploor area Parlor /2 70 1/ Sitting R. 26 Library B.R

10 Room. A. of R. A. of W. A. of W. Window area X A. " R. Floor area Din.R Ki t ch on Design D. Parlor Library Sit.Room Dining R Kitchen Design F. 26 Parlor l/2 108 l/ l/2 Library Din. R Kitchen l/2

11 Design J Room. A. of R A. of W. A. of R. A. of W. t Parlor S it.room Din.R Ki tch eri Design M< Parlor S.Room Kitchen Design 0. Parlor 8 8 2/3 403 CO CO S it.room Din.R

12 Room. A. of R. A. of W. A. of R. A. of W. Kitchen General Summaries of Leering k.tenney's Houses. Desi gn. Parlor. S.R. D.R. Ki tchen. fi. 23/ 26% D F. 15 l/ l/2 J M ll07 l/2 5 [ lz L ll7 l/2 19 l/2 18 f 18 f l/2 General Average fa 4 Or Window Area = Nearly 1/5 floor A^ea. The preceding results were taken from plans made by prominent American Architects and probably give a fa ir average ratio of the window area and the floor area, it is remarkable, that the results so nearly coincide beinr in th

13 = one case 17 l/2 % and in the other 17.7 % From these resalts a window area equal to l/6 the Floor Area would furnish sufficient light for ordinary residences. It will be seen that the ratio-also approximates to the German Rule allowing from l / r> to l/6 the flo or area. School and University Buildings. In addition to the residences previously mentioned several buildings for other purposes were examined including the D rill Hall and new Natural History Buildings, University of Illin o is. The following dimensions of Natural History Hall were taken from the plans of the Architect. Room Windows, 6 Lights 18 x 28 Size of Room 21 x 35. Window Area 249 sq.ft. Area of Room 735 " " Ratio 33 %

14 Room Windows 6 Lights IS x Window Area 166 * Floor Area «- 700 Rat io s 24 % Room Windows 6 Lt. 18 x Window Area = 75 Floor Area % Room Window Area a 188 Floor Area 736 Ratio 25 % Room Window Area 75 Floor " 481 Ratio 16

15 2j'id. Floor. Room Glass Area 240 tt Rat io 32 % Room Glass Area =, 166 Win.Area = 770 Rat io 22 % Room Glass «188 Floor 758 Ratio 24 % Room 2-17 Glass = 38 l/: Floor A. = 274 Rat io 15

16 Room 2-19 Glass - 38 Area 21 n Ratio 18 % General Room 1-11 Summary. oo% Average 22 % " " " " " " * " A l i t t l e over 1/5.

17 By measuring the D rill Hall on the same basis, the following data were obtained. 23 Windows - Area of each Windows (Transoms) - Area of each Window = = Total Area 99 x 150 = Ratio - 11 % or about 1/9 The following data we he obtained from Eveleth s School Architecture, the only available work on School Architecture. Design No. 3 Size of Room 26 x 32 = Win. 3 x 6 ' 6 * * / Design No. 6 7 Windows 3 x: 8 = 168 Room 29 x / Design No. 7 8 Win. 2'6 x Room 28 x

18 Design No. ID 8 Windows 3 x 6 = 144 Floor Surface zk Design N o.11 6 Windows 3 x 6*6" = 117 Floor Surface = X Design No.12 5 Windows 3 x 7 = 105 Floor Surface = i Design No Windows 316 x 8 = 224- Floor Surface = % Design No Windows 3 x 8 = 120 Floor Surface = # Design No.17 6 Windows 3 x 8 =144 Floor Surface = %

19 General Average. Design 3 if 6 it 7 it 10., 11 it 12 it % M «126^ = 14/f 9 or, about l/7 From the preceding data, i would appear that the following coefficien ts could be used fpr each class of Bui 1d i n g s. For residences the window area should be \/6 the fboor area. For school buildings and public buildings ingeneral l/5 the flo o r area.