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T a b l e 12. C o e f f ic ie n t s o f T r a n s m is s io n ( U ) o f P it c h e d R o o f s
Coefficients are expressed in B lu Per hour per square foot per degree Fahrenheit difference in temperature between the a ir on the two sides, and are based on an outside w in d velocity o f 16 mph.
American Society of Heating and Ventilating Engineers Guide, 1937
0.065 0.064 0.064 0.060 0.059 0.054 0.049 0.045
; 0 .1 4 I: 0 .1 1 ] 0.098
0.080 I 0.071
0.14 |I 0.12 I 0.094 I 0.089
0.063 0.062 0.062 0.058 0.058 0.053 0.048 0.044
0.092 | 0.078 | 0.069 | 0.14 | 0.11 | 0.089
I 0.091 | 0.079
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0.24 | 0.24 | 0.24 | 0.19 |
0.13 |i 0.13 | 0.13 | 0.11 I 0.11 I
0.56 | 0.34 | 0.32 | 0.32 | 0.24 | 0.23 |. 0.17 I 0.13 I o . n
0.17 |
0.13 | 0 .1 2 I! 0 .1 2 | 0.11 |
0.22 | 0.21 | 0.21 | 0.18 | o . n
0.46 | 0.30 | 0.29 | 0.29 | 0.22 || 0.21 | 0.16 | 0.12 |
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TYPICAL CONSTRUCTION
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126
Chapter 5--Heat Transmission Coefficients and Tables
13.Table
Coefficients of Transmission (U) of Doors, Windows, Skylights
and Glass Walls
r rfftiicnts are based on a wind velocity of 16 mph, and are expressed in Blu per hour per square foot per degree Fahrenheit difference in temperature between the air inside and outside ofthe door, window, skylight or wall
A. Windows and Skylights
Description
U
Single..... Double-
Triple.--
1.13. 0.45" 0.281
Nominal Thickness
Inches
1
136 136 136
2
236
3
B. Solid Wood Doors<> <
Actual Thickness
Inches
2 362
136e 136s 136 136 236 236
V
0.69 0.59 0.52 0.51 0.46 0.38 0.33
C. Glass Walls
Description
Hollow glass tile wall, 6 x 6 x 2 in. thick blocks Wind velocity 15 mph, outside surface; still air, inside surface.--
u
0.60 0.48
See Heating, Ventilating and Air Conditioning, by Harding and Willard, revised edition. 1932. `Computed using C = 1.15 for wood; f\ = 1.65 and /o = 6.0. It is sufficiently accurate to use the same coefficient of transmission for doors containing thin wood panels as that of single panes of glass, namely. 1.13 Btu per hour per square foot per degree difference between inside and outside air temperatures.
The thicknesses upon which the coefficients in Tables 3 to 13, inclusive,
are based are as follows:
Brick veneer____________________________ __________________ 4 in. Plaster and metal lath_______ ___________ :.................................. 36 in. Plaster (on wood lath, plasterboard, rigid insulation, board
form, or corkboard)--------------------- ------- ------------------------------ 36 in. . Slate (roofing) 36 jn. Stucco on wire mesh reinforcing................. .1........... ...................... 1 in. Tar and gravel or slag-surfaced built-up roofing------------ -------_ 36 in. 1-in. lumber (S-2-S)............ ..... .. ................ ............... ................... 2 362 in. 136-in. lumber (S-2-S)--------------- ---------- -------------------------------- 1366 in. 2-in. lumber (S-2-S)............................... ....................... ................. 136 in. 236-in. lumber (S-2-S)................................................................. -- 236 in. 3-in. lumber (S-2-S)......... ............ .......................... --........... :-------- 236 in. 4-in. lumber (S-2-S)____________ _________ - -...... .................. 336 in. Finish flooring (maple or oak)..... ........... ................... .......... ------- x3i6 in.
Solid brick walls are based on 4-in. hard brick(high density) and the remainder common brick (low density). Stucco is assumed to be 1-in. thick,on masonry walls. Where metal lath and plaster are specified, the metal lath is neglected.
127
T.