Document LJOzxJvzGp59Y2eDn28xyw45d

102 Chapter 4 1945 Guide approximately twice the. floor heat loss under average conditions in northern latitudes or about 4.0 Btu per hour per square foot (total, not per degree temperature difference) between the basement air and the ground at a level corresponding to the mid-height of the basement wall. Until further data are available, this value may be used with reasonable accuracy for calculating heat losses through basement walls, of heated basements. CONDENSATION IN BUILDINGS The water vapor in buildings will be transmitted through many types of building construction if there is a difference in the vapor pressures on Table 11. Coefficients of Transmission (0 of Concrete Construction Floors and Ceilings Coefficients ore expressed in Blu per hour per square foot Per degree Fahrenheit difference in temperature between the air on the two sides, and are based on still air (no wind) conditions on both sides. TYPE OF CEILING OFttHd Thickness 07 Concrete* (Inches) M in* Plaster Applied to Underside of Metal Lath and Plaster*--Suspended or Gypsum Board (M la*) and Plaster/-- InsulatingBoard I^tb (H la*) and Plaster/ 3 6 10 3 6 10 3 6 10 3. 6 10 3 6 10 No Flooring (Concrete Bare) A 0.69 0.59 . 0.50 0.62 0.54 0.46 038 0.35 032 036 033 030 035 033 032 TYPE OF FLOORING Tile* or Terrasso flooring on Concrete Kin. Battleship* Linoleum Directly on Concrete Parquet* Flooring In Mantle on Concrete B CD 0.65 0.45 0.45 036 0.41 0.41 0.48 036 036 i 3OO3 O3 ooo 0.43 039 034 037 030 030 034 038 0.28 031 036 036 O3 O5 O2 IAN9I OOO 038 038 037 0.27 034 034 034 031 033 030 031 0.19 Double Wood floor1, on Sleepers* E 035 033 032 034 032 . 031 0.19 0.18 0.17 0.19 0.18 0.17 0.15 0.15 0.14 Has SD z 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Thickness of tile assumed to be 1 in. ' *The figures in Column C may be used with sufficient accuracy for concrete floors covered with carpet. Thickness of wood assumed to be in.; thickness of mastic, M in. (k *=> 4.5). * Based on in. yellow pine or fir sub-flooring and 1S.4 in. hardwood finish flooring with an air space between sub-floor and concrete. Thickness of plaster assumed to be in. /Thickness of plaster assumed to be M in. For other thicknesses of concrete, interpolate. Table 12. Coefficients of Transmission (/) of Concrete Floors on Ground with Various Types of Finish Flooring U -- 0.103 Btu. per hour per square foot per degree Fahrenheit temperature difference between the ground and the air.over the floor. Until more complete data are available, based on tests now in progress, it is recommended that a coefficient of 0.10 be used for all types of concrete 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 explained in Chapter 6. For further data see A.S.H.V.E. Research Report No. 1213--Heat Loss Through Basement Walls and Floors, by F. C. Houghten, S. I. Taimuty. Carl Gutberlet and C. J. Brown (A.S.H.V.E. Transactions, Vol. 48, 1042, p. 369). i%-. A ? & .'itt >4 ' Heat Transmission Coefficients 103 Table'13. Coefficients of Transmission (U) of Flat. Roofs Covered with Builtup Roofing. No Ceiling--Under Side of Roof Exposed (See Table 14 for Flat Roofs with Ceilings) These coefficients are expressed in Btu per hour per square foot per degree Fahrenheit difference in temperature between the air on the,two sides, and are based on an outside wind velocity of 15 mph. TYPE OF ROOF DECK Thickness 07 Root Deck (Inches) No Insula tion INSULATION ON TOP OF DECK (Covered with Built-Up Rooting) Insulating Board . (Thickness Below) CORXBOABD (Thickness Below) Min. 1 In. IM In. 2 In. 1 In. 1M In. 2 In. aHs 'Z, ABCDE FGH Flat Metal Roof Deck* !N/UUTtt/ paoHH<sa*/ Tok urta yeck 0.94 039 034 0.18 0.14 033 0.17 0.13 1 Precast Cement Tile /CUT JtoeriNCj /Tu.6 1M in.- `V/oppfR.r/-^ 034 037* 034 0.18 0.14 032 0.16 0.13 . 2 Concrete IM/ULfiYlON. kOOHHGj / CW CRETE./ 2 in. 4 in. 6 in. 032 037 0.24 0.17 0.14 032 0.16 0.13 3 0.72 034 033 0.17 0J3 031 0.16 0.12 4 0.65 033 032 0.16 0.13 031 0.15 0.12 5 Gypsum and Wood Fiber* on ^4 in. Gypsum Board * ItUOL/tftOrt, 2H in. 0.40 0.25 0.18 0.14 0.12 0.17 0J3 0.11 6 R"Fir,6) / 3in. - 032 032 0.16 0.13 0.11 0.15 0.12 0.10 7 ATf/vnrv.-. fia jtc*. &a*p' Wood* utopS 1 in. IMin. 2 in. 3 in. 0.49 038 030 0.15 0.12 0.19 0.14 0.12 8 037 034 0.18 0.14 0.11 0.17 0.13 0.11 9 032 032 0.16 . . 0.13 0.11 0.16 0.12 0.10 10 033 0.17 0.14 0.11 0.096 0.13 0.11 0.091 11 . ^Coefficient of transmission of bare corrugated iron (no roofing) is 1.50 Btu per hour per square foot of projected area per degree Fahrenheit difference in temperature, based on an outside wind velocity of 15 mph, per cent gypsum, 12)4 per cent wood fiber. Thickness indicated includes H in. gypsum board. `Nominal thicknesses specified--actual thicknesses used in calculations.