Document wD3v85Q8BVZOBLyyDrLwZzXo6

192 CHAPTER 9 1954 Guide Table 13. Coefficients of Transmission ({/) of Concrete Construction Floors and Ceilings Coefficients are expressed in Bin per (hour) (square foot) (Fahrenheit degree difference in temperature between the atr on the two rides), and are baaed on still air (no trtnrf) conditions on both rides. TYPE OF CEILING 0RAW<3 Typ E OP Floo EUNO Thickness op Concrete (Inches) No Flooring (Concrete Bare) . Tile or -Terrazzo Flooring on Concrete H In. Asphalt Tile Directly on Concrete Parquett* Flooring in Mastic on Concrete Double Wood Floor on Sleepers ce a a s zD ABC DE H in. Plaster Applied to Underside of Concrete............................................. Metal Lath and Plaster'--Suspended or Furred........................................... Gypsum Board (H in.) and Plaster-^-- Suspended or Furred....................... Insulating Board Lath (H in.) and Piaster-^--Suspended or Furred___ 6 10 3 6 10 3 610 3 6 10 3 6 10 0.59 0.50 0.63 0.54 0.46 0.38 0.35 0.32 0.36 0.33 0.30 0.25 0.23 0.22 0.65 0.56 0.48 0.59 0.52 0.44 0.37 0.34 0.31 0.35 0.32 0.29 0.24 0.23 0.21 0.66 0.58 0.49 0.60 0.53 0.45 0.37 0.35 0.32 0,35 0.33 0.30 0.25 0.23 0.22 0.45 0.41 0.36 0.43 0.39 0.34 0.30 0.28 0.26 0.28 0.27 0.24 0.21 0.20 0.19 0.25 0.23 0.22 0.24 0.22 0.21 0.19 0.18 0.17 0.19 0.18 0; 17 0.15 0.15 0.14 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Thickness of tile assumed to be 1 in. 6 Conductivity of asphalt tile assumed to be 3.1. c Thickness of wood assumed to be ii in.; thickness of mastic, i in. (it * 4.5). Col. D may also be used for concrete covered with carpet. * Based on it in. yellow pine or fir sub-flooring and 13 in..hardwood finish flooring with an air space between sub-floor and concrete. * Thickness of plaster assumed to be 3 in. J Thickness of plaster assumed to be j in. 9 For other thickness of concrete, interpolate. Table 14. Coefficients of Tbansmission (U) of Concrete Basement Floors on Ground with Various Types of Finish Flooring- U = 0.10* Btu per (hr) (sq ft) (Fahrenheit degree temperature difference between the ground and the air over the floor). Since authentic data are not available, this coefficient is sometimes used for concrete floors on ground. For more recent procedures1* refer to National Bureau of Standards Report BMS-103. is also assumed that the glass loses heat by radiation to the ground and to the clear sky, which together have an effective radiating temperature below the air temperature. It is therefore necessary to determine, by trial and error, the temperature of the outdoor glass surface such that the sum of the radiation and convection losses equals the heat conducted through the glass section, and equals the heat'delivered to the glass from the heated space. This heat flow, divided by the air-to-air temperature difference, results in a U value which is used in the usual manner. The equivalent surface conductance for radiation and convection combined, based on airlo-svrface temperature difference, therefore varies from about 5.5 for sin gle glass to about 6.6 for double glass for exactly the same environmental design conditions. It is assumed that the room air temperature equals the average tem perature of the room surfaces seen by the glass. Special consideration .should be given to those cases where the glass sees interior surfaces at Heat Transmission Coefficients of Building Materials 193 Table 15. Coefficients of Transmission (U) of Flat Roofs Covered with Built-up Roofing. No Ceiling--Under Side of'Roof Exposed (See Table 16 for Flat Roofs with Ceilings) areaWp 5fieSf~of transmission of bare corrugated iron (no roofing) is 1.50 Btn per (hr) (sq It of projected ' ueg difference in temperature) based on an outside wind velocity of 15 mph. percent gypsum, 124 percent wood fiber. Thickness indicated includes 4 in. gypsum board. C*0mma' ^^*c^cnessea specified actual thicknesses used in caicuistions.