Document Jra2gpOGV54rpaMnDmMRQQp86
176
CHAPTER 9
1951 Guide
Tablb 1. Conductances (C) fob Surfaces and Air Spaces All conductance solus axpressed in Btu per (hour) (square foot) (Fahrenheit degree temperature difference.
Section A. Surface Conductances for Still Alra
Position of Surface
Direction of Heat Flow
Surface Emissivity
- 0.83
e - 0.05
Upward Downward
1.95 1.21 1.52*
1.16 0.44
0.74
Section B. Conductance of Vertical Spaces at Various Mean Temperatures!*
MEAN .Temp Fahr Dbg
Conductances of Air Spaces for Various Widths in Inches
0.128
0.250
0.364
0.493
0.713
1.00
1.500
20
2.300
1.370
1.180
1.100
1.040
1.030
1.022
30
2.385 . 1.425
. 1.234 - 1.148
1.0S0
1.070
1.065
40
2.470
1.480
1.288
1.193
1.125
1.112
1.105
50
2.560
1.535
1.340 -
1.242
1.168
1.152
1.149
60
2.650
1.590
1.390
1.295
1.210
1.195
1.188
70
2.730
1.648
1.440
1.340
1.250
1.240
1.228
80
2.819
1.702
1.492
1.390
1.295
1.280
1.270
90
2.908
1.757
1.547
1.433
1.340
1.320
1.310
100
2.990
1.813
1.600
1.486
1.380
1.362
1.350
110
3.078
1.870
1.650
1.534
1.425
. 1.402
1.392
120
3.167
1.928
1.700
1.580
1.467
1.445
1.435
130
3.250
1.980
1.750
1.630
1.510
1.485
1.475
140
3.340
2.035
1.800
1.680
1.550
1.530
1.519
150
3.425
2.090
1.852
1.728
1.592
1.569
1.559
Section C. Conductances and Resistances of Air Spaces Faced on One Surface with Reflective Insulationo
Location and Position of Air Space
Direction
of Heat Flow
Temp* Diff Fahr Deg
Winter Summer
Conductance* (O
No. of Air Spaces
123
Resistance*
(i)
No. of Air Spaces
123
Rafter Space (8 in.) Horizontal
Horizontal
Down Up .
45 45
0.10 0.07 0.27 0.17
10.00 14.29 3.70 5.88
Horizontal - Horizontal
Down Up
25
0.09 0.06
.11.11 16.67
25
0.24 0.16
4.17 6.25
30 deg slope - 30 deg slope
Down Up
45 45
0.15 0.10 0.25 0.17
6.67 10.00 4.00 5.88
30 deg slope 30 deg slope
Down Up
25 , 25
0.13 0.09 0.23 0.14
7.69 11.11 4.35 7.14
Stud Space (3H in.) Vertical'
Vertical
30. 0.34 .
2.94
40
0.23 0.13
4.35 . 7.69
Vertical' Vertical
15 0.32
3.13
20
0.18. 0.11
5.56 9.09
Vertical*
30 0.46
2.17
Radiation and Convection from Surfaces in Various Positions, by G. B. Wflkee and C. M. F. Peterson (A.S.H.V.E. Transactions, Vol. 44, 1038, p. 513).
* AJ3.H.VJ3. Research Report No. 825--Thermal Resistance of Air Spaces, by F. B. Rowley and A. B. Algren (A.SJ3.V.E. Transactions, Vol. 35, 1929, p. 165).
* Thermal Test Coefficients of Aluminum Insulation for Buildings, by G. B. Wilkes, F. G. Hechler and G. R. Queer (A.S.H.VJ2. 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 emisrivity 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.
' ' ' Stud space is lined on plaster base side with loose'paper with aluminum on surface faring air space. . The resistance of the small air space.between-the piaster base and paper was 0.43. -
9 Radiation and Convection Across Air Spaces in Frame Construction, by G. B. Wilkes and C. M. FI
Peterson (A.S.H.V.K Transactions, Vol. 43, 1937, p. 351).
'
* The recommended surface conductance for calculating heat losses for still air for non-refleetive surfaces is 1.65 Btu. For a 15 mph wind vdority,'the reoommehaed 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 vertical
surfaces.
Heat-Transmission Coefficients of Building-Materials
177
Tablb>2.? `Conductivities (fc) and Conductances-(C)'of-Building and Insulating Materials :
These constants or, expressed in Btu per (hour) {square foot) (Fahrenheit degree temperature difference). - Conductivities (k) are per inch thickness and conductances (C) are for thickness or construction stated, not per inch thickness.
CONDUCTIYITT OB Conduct
ance}
Description
Per For
Inch Thick
n\(*)
(O
Thick ness ness Listed
n\
w VC/
BUILDING BOARDS (Non-Insulating) --
Compressed cement and as bestos sheets..................... .
Corrugated asbestos board.. Pressed asbestos mill board. Gypsum board--gypsum
between layers of heavy*
paper.............................. I in. gypsum board....... t in. gypsum board......... | in. gypsum board.........
123 20.4 60.5
' 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 a.per, siding 4 in. wide........
ellow pine lap siding..........
MASONRY MATERIALS Bbick..................... .........
Damp or wet................. Common yellow clay bricka. One tier yellow common
clay brick, one tier face brick, approx. 8 in. thick0.
Clay Tile, Hollow --
2 in. Tile, | in. plaster both
sides..................................... 4 in. Tile, i in. plaster both
sides..................................... 6 in. Tile, i in. plaster both
sides..................................... 8 in. Tile, average of 8 types
(Walls No. 69. 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.*......................
120.0 127.0 124.8
2.70 0.87
0.48
2.08
0.84 1.19
3.73 2.82 2.60
(3) 0.27 0.35 0.38 (X)
(4)
0.50
2.00 (4)
0.82
1.22 (4)
810.85 1.18
1.28 0.78
5.0* 4.8
0.20 0.21
0.77 1.30 (4)
1.00 1.00 (2) 0.60 1.67 (2) 0.47 2113 <2)
0.52 1.92 (4) 0.26 *8^84'' (4)
Authorities: U. S. Bureau of Standards, tests based on samples submitted by manufacturers.
1 A. C. Willard, L. C. Lichty and L. A. Harding, tests conducted at the Univeisity of Illinois. .
* J. C. Peebles, testa conducted at Armour Institute of Technology, based on samples submitted by manufacturers.
F. B. Rowley, et al, tests conducted at the Univeisity of Minnesota. * 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).
* 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).
c The Effect of Convection in Ceiling Insulation, by G. B. Wilkee and L. R. Vianey (AJ3.H.V.E. Trans actions, Vol. 49, 1943, p. 196).
. 4 See AJ3.H.VJ3. Research Report No. 915--Conductivity of Concrete, by F.-C. Houghten and Carl Gutberlet (AJ3.H.VJE. Transactions, Vol. 38, 1932, p. 47).
* See Heating, Ventilating and Air Conditioning, by Harding and Willard, revised edition, 1932.
S See BMS13, U. 8. Department of Commerce, National Bureau of Standards, Washington, D. C.
9 Roofing, 0.15 in. thick (1.34 lb per square foot), covered with gravel (0.83 lb persquare foot), combined
thickness assumed 025.
.-