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170 CHAPTER
. Table 1. Conductances (C) for Surfaces and Air Spaces All conductance values expressed in Btu per (hour) (square foot) (Fahrenheit degree temperature difference)
Section A. Surf#v
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B< Conductance of Vertical Spaces at Various Mean Temperature^ Conductances of Air Spaces for Various Widths in Inches
0.128
0.250
0.364'
0.493
0.713
1.00
1.600
20 30
40 60 60
70 80 90 100 110 120 130 140 160
2^00
2.385 2.470 2.560
2.650
2.730
2.819 2.908
2.990 3.078
3.167 3.250 3.340
3.425
1.370
1.425 1.480
1.535 1.590
1.648 1.702
1.757 1.813
1.870
1.928 1.980 2.035
2.090
1.180
1.234
1.288 1.340
1.390
1.440
1.492
1.547 1.600
1.650 1.700 1.750
1.800 1.852
1.100
1.148 1.193
1.242 1.295
1.340 1.390
1.433 1.486
1.534 1.580
1.630 1.680
1.728
1.040 1.080
1.125
1.168 1.210
1.250 1.295 1.340
1.380
1.425
1.467 1.510
1.550 1.592
1.030
1.070 1.112
1.152
1.195 1.240 1.280 1.320
1.362
1.402
1.445 1.485
1.530 1.569
1.022
1.065
1.105
1.149
1.188 1.228
1.270
1.310 1.350 1.892
1.435
1.475 1.519 1.559
Sec^J"5* Conductances and Resistances of Air Spaces
raced on One Surface with Reflective Insulations
Location and Position or Ajs Spacs
Rafter Space (8 in.) Horizontal Horizontal
Horizontal ' Horizontal
30 deg slope 30 deg slope
30 deg slope 30 deg slope
Stud Space (3Min.) Vertical/ Vertical
Vertical/ Vertica]
Vertical*
Direction
Temp* Dzft Fahr Dbg
Flow
Winter Summer
Conductance* fO
No. of Air Spaces 123
Resistance* VC /
No. of Air Spaces 1 23
Down Up
Down Up
Down Up
Down Up ,
45 45
45 45
25 25
25 25
0.10 0.27
0.09 0.24
0.15 0.25
0.13 0.23
0.07 0.17
0.06 0.16
0.10 0.17
0.09 0.14
10.00 3.70
11.11 4.17
6.67 4.00
7.69 4.35
14.29 5.88
16.67 6.25
10.00 5.88
11.11 7.14
30 40
0.34
0.23
0.13
2.94
4.35 7.69
15 20
0.32
0.18
0.11
3.13
5.56 9.09
30 0.46
2.17
iwnuauuu tuia i/onvection irons Surfaces in Various Positions, by G. B. Wilkes and C. M. F. Peterso (A.S.H.V.E. Transactions, Vol. 44, 1938, p. 513.)
6 A.S.H.V.E. Research Report No. 825--Thermal Resistance of Air Spaces, by F. B. Rowley and A. t Algren (A.S.H.V.E. Transactions, Vol. 35, 1929, p. 165).
c Thermal Test Coefficients of Aluminum Insulation for Buildings, by G. B. Wilkes, F. G. Hechler an E. R. Queer (A.S.H.V.E. Transactions, Vol. 46, 1940).
d Temperature difference is based on total space between plaster base and sheathing, flooring or roofing
* These air space conductance and resistance values are based on one reflective surface (aluminum) hav ing an emissivity of 0.05 facing each'space, and are based on total space between plaster base and sheathing flooring or roofing. The rafter and stud spaces are divided into equal spaces.
f Stud space is lined on plaster base side with loose paper with aluminum on surface facing air space
The resistance of the small air space between the plaster base and paper was 0.43.
0 Radiation and Convection Across Air Spaces in Frame Construction, by G. B. Wilkes and C. M. F Peterson (A.S.H.V.E. Transactions, Vol. 43, 1937, p. 351).
. 4 The recommended surface conductance for calculating heat losses for still air for noa-reflective surfaces
is 1.65 Btu. For a 15 mph wind velocity, the reoommended value is 6.0 Btu. These coefficients were de
rived from Fig. 4, which was based on tests conducted at the University of Minnesota, and apply to vertica
surfaces.
;
Heat ,Transmission Coefficients of Building. Materials
171
Table 2. Conductivities (k) and Conductances (C) of Building and Insulating Materials
These constants ore expressed in Btu per (four) (square foot) (Fahrenheit degree temperature difference):
Conductivities (i) are per inch thickness arid conductances (C) are for thickness or *rm.ahntctwn. stated, not ver inch thickness.
Description
"uo Conduct
P O
Q ivity- OB Resistance es Conduct
PS oa<
ance
p.
a J
Px Per For
sa Eh
w
Inch Thick
(cn
Thick ness ness Listed
o
sz 2a <B
OS
(i)
G) Xfpc* <
BUILDING BOARDS (Non-Insulating).......
Compressed cement and as
bestos sheets........................ Corrugated asbestos board. Pressed asbestos mill board . Gypsum board--gypsum
between layere of heavy
paper............ .................. f in. gypsum board............. J in. gypsum board..........
| in. gypsum board.............
118 119 4.1
20.4 , no 0.48
60.5 86 0.84
62.8 53.5
70- 1.41
__
90 -
FRAME CONSTRUC-
TION
COMBINA-
TIONS
1 in. fir sheathing and build
ing paper..-........... 1 in. fir sheathing, building
paper and yellow pine lap
siding.................... ' 1 in. fir sheathing, building
paper and stucco... - - - Pine lap siding and building
papier, siding 4 in. wide...
Yellow pine lap siding.......
--
_
_
--
30
20 _ 20 . __ 16
---
-- --
_
3.73 2.82 2.60
0.86
0.50
0.82
0.85 1.28
0.24 2.08 1.19
0.71 -- -- --
-
--
-
__
--
MASONRY MATERIALS Brick........................................
Damp or wet..............- - Common yellow clay brick One tier yellow common
clay brick, one tier face
brick, approx. 8 in. thick.
-
_
5.0* -- 4.8
--
0.20 0.21
_ -- 0.77 -
Clay Tile Hollow..
2 in. Tile, i in. plaster both
sides............................ 4 in. Tile, \ in. plaster both
6 in. Tile, i in. plaster both sides............
8 in. Tile, average of 8 types (Walls No. 59, 63, 64, 66, 67, 90, 91. 92)............
12 in. Clay tile wall: 8 in. x 5 in. x 12 in. and 4 in. x 5 in. x 12 in...........
120.( 127. () 124. )
--
-
110 100 105
-
1.00 -- 0.60 - 0.47
- 0.52
- 0.26
-
U) -- (2)
(3)
_
0.27 0.35 0.38
(3) (1)
1.16 (4)
2.00
1.22
1.18 0.78
_
(4) (4) <4) (4)
(2) (4)
1.30 (4)
1.00 1.67 2.13
(2) .(2)
(2)
1.92 (4)
3.84 (4)
Authorities: 1 National Bureau of Standards, tests based on samples submitted by manufacturers. * A. C. Willard, L. C. Liehty and L. A. Harding, tests conducted at the University of Illinois. * J. C. Peebles, testa conducted at Armour Institute of Technology, based on samples submitted by manu
facturers. 4 F. B. Rowley, et al, tests conducted at the University of Minnesota. 1 A.S.H.V.E. Research Laboratory. * E. A. Allcut, tests conducted at the University of Toronto. See Thermal Conductivity of Building Materials, by F. B. Rowley and A. B. Algren (University of
Minnesota Engineering Experiment Station Bulletin No. 12). b Heat Transmission Through Insulation as Affected by Orientation of Wall, by F. B. Rowley and C.
E. Lund (A.S.H.V.E. Transactions, Vol. 49, 1943, p. 331). e The Effect of Convection in Ceiling Insulation, by G. B. Wilkes and L.R. Vianey (A.S.H.VJ3. Trans
actdioSnese. AV.oSl..H49..V1.E94.3,Rpe.s1e9a6r).ch Report No. 915--Conductivity of Concrete, by F. C. Houghten and Carl
Gutberiet (A.S.H.V.E. Transactions, Vol. 38, 1932, p. 47). 4 See Heating, Ventilating and Air Conditioning, by Harding and Willard, revised edition, 1932. * See BMS13, U. S. Department of Commerce, National Bureau of Standards, Washington, D. C. 0 Roofing, 0.15 in. thick (1.34 lb per square foot), covered with gravel (0.83 lb per square foot), combined