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,^g;at Twismission Coefficients of Bmiding'Materials
137 .
_ r 12 Coefficients of Transmission (17) of Concrete Construction
Iabui
Floors and Ceilings
are expressed in Btu per (hour) (square foot) (Fahrenheit degree difference in temperature between
Coefficienu
^^ ^
anj ore based on still air (no wind) conditions on both sides.
type of ceiling
TYPE OF FLOORING
Thickness or
. Concrete* (Inches)
Ho Ceiling--------- ---------- -----------------------
in. Plnster Applied to Underside of Concrete.............................- ---
Metsl Lett nod Fleeter*--Suspended or Furred----------- ---- ------------------------
Gypsum Board (M in-) and Plaster/-- Suspended or Furred.........................---
InsulatingBoard Lath (H in-) and Plaster/ Suspended cr Furred----------------- .--......
3 6 10
3 6 10
3 6 10
3 6 10
3 6 10
No Flooring (Concrete
Bare)
TBs* or Terraxxo
Flooring on
Concrete
A
0.68 0.59 0.50
0.62 0.54 0.46
0.38 035 032
036 033 030
035 033 032
ooo
B
0.65 036 0.48
039 032 0.44
037 034 031
034 033 031
X In.
Asphalt TUe*
Directly; on
Concrete
Parquet*
Flooring In
Mastie
on Concrete
CD
poo S&8 eeo
0.45 0.41 036
0.60 0.43 0.53 039 0.45 034
037 030 035 038
032 036
035 0.33
0.30
0.25 031 0.23 0.20' 0.22 aio
Double Wood Floor
on -
Seepen*
a i
z
E
035 , f 033 2 032 3
034
032 031
4 6.
6
0.19
0.18 . 0.17
7 8 9
0.19 10 0.18 11 0.17 12
0.15 13 0.15 14 0.14 15
Thickness of tile assumed to be 1 in. b Conductivity of Asphalt Tile assumed to be 3.1.
e Thickness of wood assumed to be H in.; thickness of mastic, | in. (k = 4,5). Col. D may also be used for concrete covered with carpet.
on |f in. yellow pine or fir sub-flooring and tf in. hardwood finish flooring with an air space be tween sub-floor and concrete.'
* Thickness of plaster assumed to be | in. / Thickness of plaster assumed to be f in.
0 For other thicknesses of concrete, interpolate.
Table 13.
(U)Coefficients of Transmission
of Concrete Floors on Ground
with Vahious Types of Finish Flooring
U = 0.10" Btu per (hour) (square foot) (Fahrenheit degree temperature difference between the ground and the air over the floor).
Until more complete data are available, it is recommended that a coefficient of 0.10 be used for all types of ooncrete floors on the ground, with or without insulation.- For basement wall below grade, use the same average coefficient (0.10). A lower ground temperature should, however, be used for walls than floors as ex plained in Chapter 14. For further data see A.S.H.V.E. Research Report No. 1213--Heat Loss Through Basement Walls and Floors, by F. C. Houghten, 8. I. Taimuty, Carl Gutberlet and C. J. Brown (A.S.H.V.E. Transactions, Vol. 48, 1942, p. 369).
of the ground, on the material constituting the wall or floor, and on the conductivity of the surrounding earth. The conductivity of the earth will vary with local conditions and is usually unknown. Tests8 at the A.S.H.V.E. Research Laboratory indicate a heat flow of approximately 2.0 Btu per (hour) (square foot) through an uninsulated concrete base ment floor with a temperature difference of 20 F between ground tem perature and the air temperature 6 in. above the. floor. Based on this result, a coefficient of 0.10 Btu per (hour) (square foot) (Fahrenheit degree, difference) is recommended for calculation where it is desirable to allow for the small basement floor heat loss, e.g. for heated basements.
For basement walls the same coefficient may. be used, but due to closer proximity to the surface of the ground, the temperature difference for win ter design conditions will be greater than for the floor. The test results ^