Document 2jO2j15Yyn40mvoYmdq2G3ZwR
116
CHAPTER 6
1946 Guide
Table l. Conductances (C) for Surfaces and Air Spaces
All conductance values expressed in Btu per (hour) (square foot) (Fahrenheit detree temperature difference).
Section A. Surface Conductances for Still Air*
Position of Surface
Direction of Heat Flow
' Surface Emissivity
e 0.83
e - 0.05
Upward Downward
1.21 . 1.52*
0.74
Section B. Conductance of Vertical Spaces at Various Mean Temperaturesb
Mean
Temp Fahr Deg
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
1.080
1.070
1.065
40
2.470
1.480
1.288
1.193
1.125
1.112
11105
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 Insulation^
Location and Position of Air Space
Direction
of Heat Flow
Temp Diff Fahr Deg
Winter Summer
Conductance* (C)
No. of Air Spaces
1 23
Resistance*
()
` No. of Air Spaces
1 2 3*
Rafter Space (8 in.) Horizontal Horizontal.
Horizontal Horizontal
Down Up
Down Up
45 45
25 - * 25
0.10 0.27
0.09 0.24
0.07 0.17
0.06 0.16
10.00 3.70
11.11 4.17
14.29 5.88
16.67 6.25
30 deg slope 30 deg slope
Down Up
45 45
0.15 0.25
0.10 0.17
6.67 4.00
10.00 5.88
30 deg slope 30 deg slope
Stud Space (Z*A in-) Vertical/ Vertical .
Down Up
30 40
25
0.13
0.09
' 7.69 11.11 .
25
0.23
0.14
4.35
7.14
'
0.34
0.23
0.13
2.94
. 4.35
7.69
Vertical/ Vertical
15 05^
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. Wilkes and C. M. F. Peterson (A.S.H.V.E. Transactions, Vol. 44, 1938, p. 513).
6A.S.H.V.E. Research Report No. 825--Thermal Resistance of Air Spaces, by F. B. Rowley and A. B.
Algren (A.S.H.V.E. Transactions, Vol 35, 1929, p. 165).
'
"Thermal Test Coefficients of Aluminum Insulation for Buildings, by G. B. Wilkes, F. G. Hechler and E. R. Queer (A.S.H.V.E. Transactions. Vol. 46. 1940).
^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)' having an emissivity of 0.05 facing each space and are based on total space between plaster base and sheath* ' . ing, 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 facing air space. The resistance of the small air space between the plaster base and paper was 0.43.
"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).
The recommended surface conductance for calculating heat losses for still air for non-reflective surfaces la 1.65 Btu. For a 15 mph wind velocity, the recommended value is 6.0 Btu. . These' coefficients were derived from Fig. 3 which was based on tests conducted at the .University of Minnesota, and apply to vertical surfaces.
Heat Transmission Coefficients of Building Materials
117
Table 2.
Conductivities (k) and Conductances (C) of Building and Insulating Materials
These constants are 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.
Material
Description
- Conduct!v itt '
Resistance ^
Dbnbitt (Lb pub
Mean Temp
Co Ft) Deo)
OR Conductance
> (O
Per Inch Thickness
For Thickness
Listed
0
U)
(*)
1
<
BUILDING BOARDS (NoN-lKSULATINa)-----
Compressed cement and asbestos sbeeta_ 123
86 2.70
057
Corrugated aabestoB board___ --___,,___ 20.4 110
0.48 _
2.08
Pressed asbestos mill board..... ..
60.5
86
054
-1.19
Gypsum board--gypsum between layers
of heavy paper___ ________________ __--- 62.8
70
1.41
0.71
H in. gypemaboard..--__ _________ ______
.
3.73
H in- gypsum board___ ____________ ___
252
H in- gypsum board_______________
535
90 --
2.60 --
--
0.27 055 0.38
(1) 2) (3)
(3)
(1)
FRAME CONSTRUCTION 1 in. firsheathing and building paper.......... ____
30 --
056 --
COMBINATIONS-------------- 1 in. fir sheathing, building paper and
yellow pine Upsiding.............. .................. ____
20 --
050 ------
1 in. fir sheathing, building paper and
stucco............................. ..............________ ____
20 ____
052
Pine lap siding and building paper, Biding
4 in. wide.__......_________________ _____
16
055
Ycllow pine lapriding,........ --............. .. ...... --
---
1.28
MASONRY MATERIALS
Brick.--...........-------------- --
Damp or wet____ ______________ ___ ______
5.0* 0.20
Common yellow day brick__--__________ --
45 - ,,
051
One her yellow common day brick, one
tier face brick, approx. 8 in. thick,..... ,, -- -- -- 0.77
1.16 (4) 2.00 (4) 152 C4)
1.18 S41'
0.78 (4)
-- 150
(2) (4)
(4)
Clat Tub, Hollow------------
2 in. Tile, H in. plaster both rides.________ 4 in. Tile, H in. plaster both sides............... 6 in. Tile, Yi 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: 8in.x5in.xl2in.
and 4 in. x 6 in. x 12 in......-............ _.......
120.0 127.0 1245
____
____
110 100 105
--
--
` Concrete.
Sand and gravel aggregate, various ages and miTM <__________________
Sand and gravel aggregate.--__ _______ limestone aggregate_______________ ______ Cinder aggregate!__________ __________ __ Steam treated limestone slag aggregate.,. Pumice (Mined in California) aggregate. Expanded burned day aggregate________ Burned clay aggregate. Blast furnace slag aggregate!........ :...........
Expanded vennkuliteaggregate--____ _ Expanded vermiculite aggregate,________
. __
142 75 132 - 75 97 75 74.6 . 75
65.0 75 59.9 75 67.1 75 76.0 70 20 90 26.7 90
1.00 0.60 -- 0.47 --
052 --
--
056 --
1155
to ,,
1656
12.6
105
4.9
257
2.42-
__
258 256
__
1.6
0.68 `
0.76
0.09 to
0.06 0.08 . 0.09 052 0.44
0.41 0.44 055 0.63 1.47
152
' 150 1.67 2.13
(2)
(2) (2)
1.92 (4)
3.84
* ____
(4) (5)
,,__ ...... ____
____
__ _ --
(4) (4) (4) 4) (4) (4)
(4) (3)
3 (3)
Authorities:
lU. S. Bureau of Standards, tests based on samples submitted by manufacturers.
*A. C. Willard, L. C. Lichty and L. A. Harding, tests conducted at' the University of Illinois.
*J. C. Peebles, tests conducted at Armour Institute of Technology, based on samples submitted by manufacturers.
*F. B. Rowley, et al. tests conducted at the University of Minnesota.
A.S.H.V.E. Research Laboratory.
*E. A. AUcut, 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).
* 6Heat 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).
The Effect of Convection in Celling Insulation, by G`. B. Wilkes and L. R. Vianey (A.S.H.V.E. Trans actions, Vol. 49, 1943. p. 196).
*See A.S.H.V.E. Research Report No. 915--Conductivity of Concrete, by F. C. Houghten and Carl Gutberlet (A.S.H.V.E. Transactions, VoL 38, 1932. p. 47).
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.
"Roofing, 0.15 in. thick (1.34 lb per square foot), covered with gravel (0.83 lb per square foot), combined--------
thickness assumed 0.25.
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