Document mq6nERDV5Vy4VOarDZLN9K3Vk

176 CHAPTER 9 1958 Guide' ; 5 Table 3. Conductances (C) fob Subfaces and Aib Spaces All conductance values expressed in Btu per (hr) (sq ft) (F deg temp diff) Section A. Surface Conductances for Still Air* Surface Emissivity Position op Surface Direction op Heat Flow Non-Reflective e = 0.90 Refleotive -- 0.20 Reflective < = 0.05 C RC R C R Horizontal.......................................... Sloping--45 deg................................. Vertical................................................ Sloping--45 deg.................................. Horizontal.......................................... Upward Upward Horizontal Downward Downward 1.63 0.61 0.91 1.10 0.76 1.32. 1.60 0.62 0.88 1.14 0.73 1.37 1.46 0.68 0.74 1.35 0.59 1.70 1.32 0.76 0 60 1.67 0.45 2.22 1.08 0.92 0.37 2.70 0.22 4.55 * Conductances are for surfaces of the stated emissivity facing surroundings having an emissivity equal to 0.9 and at the same temperature as the ambient air. Values are based on a surface-air temperature differ ence of 10 deg and for surface temperature of 70 F. (See Table 4 for surface conductances for moving air.) iv i*'\' Section B. Thermal Conductances and Resistances of a Plane* Air Space* Position of Air Space Heat Flow Air Space Thick ness1* Inches Mean Temp F Temp Dot deg Thermal CONDUCTANCE-C Value of E-d 0.05 0.2 0.5 0.82 Thermal . Resistance-72 Value of Ed 0.05 0.2 ` 0.5 0.82 if Horiz. 45 Slope Vert. 45 Slope Horiz. Up H to4 50 50 10 0.41 0.55 0.82 1.11 2.44 1.83 1.22 0.90 30 0.54 (1.68 0.95 1.24 1.84 1.47 1.05 0.80 90 10 0.41 0.58 0.92 1.28 2.47 1.73 1.09 0.78 Up H to 4 50 50 10 0.35 0.49 0.76 1.05 2.84 2.05 1.31 0.95 30 . 0.48 0.62 0.89 1.18 2.08 1.62 1.13 0.85. 90 10 0.35 0.52 0.86 1.23 2.85 1.92 1.16 0.81 Horiz. H to 4 50 50 90 10 0.28 0.42 0.69 0.99 3.52 2.37 1.44 1.62 30 0.38 0.52 0.79 1.08 2.64 1.94 1.27 0.92 10 0.29 0.46 0.80 1.16 3.49 2.19 1.25 0.86 Down H to 4 Down* H 1)4 4 50 50 90 50 50 50 10 0.24 0.38 0.65 0.94 4.14 2.65. 1.54 1.06 30 0.30 0.43 0.71 1.00 3.36 2.30 1.41 1.00 < 10 0.25 0.42 0.76 1.12 4.07 2.40 1.32 0.89 20 0.28 0.42 0.69 0.98 3.57 2.38 1.45 1.02 .ti? 20 0.18 0.31 0.58- 0.87 5.56 3.23 1.73 1.15 Ti ~ 20 0.11 0.25 0.52 0.81 8.94 4.03 1.92 1.23 H 1)4 4 90 20 0.31 0.48 0.82 1.18 3.23 2.08 1.22 0.85 90. 20 0.20 0.37 0.71 1.07 5.00. 2.70 1.41, 0.93 <! 90 20 0.13 0.30 0.64 1.01 7.82 3.35 1.56 0.99 Notes: * Spaces of uniform thickness, bounded by moderately smooth surfaces. k Where a range of thickness is given, the given conductance is the average over the range; extreme values within the range differ therefrom by less than 10 percent. 0 Interpolation, and moderate extrapolation, of conductance values are permissible for other values of -A'j mean temperature, temperature difference and effective emissivity E. v 111 , . . /*?V; ^ Effective emissivity of space, E, is given by -- = -- 4* -- -- .1 where ti and ejare the emissivities, .J. < of the surfaces of the air space. (See Section C, below). _ ; f The conductances of horizontal spaces with heat flow downward are substantially independent of / ;t&/: temperature difference. Based on National Bureau of Standards data presented in Housing Research Paper No. 32, Housing `ana..2* Home Finance Agency, 1954 (U. S. Government Printing Office, Washington, D. C.) ' Section C. Reflectivity and Emissivity Values of Various Surfaces* and Effective Emissivities of Air Spaces __________________ Surface Reflectivity IN PERCENT Average Emissivity Effective Emissivity E of Air space With one sur face having emissivity e and other 0.90 With both surfaces of emissivity Aluminum foil, bright................................ Aluminum sheet.......................................... Aluminum coated paper, polished........... Steel, galvanized, bright............................ Aluminum paint......................................... Building materials: wood, paper, glass, masonry, non-metallie paints................ . 92 to 97 80 to 95 75 to 84 70 to 80 30 to 70 5 to 15 0.05 0.12 0.20 0.25 0.50 0.90 0.05 0.12 0.20 0.24 0.47 0.82 0.03 0.06 0.11 0.15 0.82 See also Chapter 5, Table 3. Heat Transmission Coefficients of Building Materials 177 Table 4. Conductivities (k). Conductances (C) and Resistances (R) of Building and Insulating Materials (Design Values)* These constants are expressed tn Btu per (hour) (square foot) (Fahrenheit degree temperature difference). Conductivities (4) are per inch thickness and, conductances (CO are for thickness or construction stated, not per inch thickness. Conductivity or Conductance Resistance (R) Material Description Density (Lb. per CuFt) (4) fa3 -S 0(C) CL tag flj G) G) AIR SPACES1* See Table 1--Section B. Position Heat Flow * Thickness Horizontal........Up (Winter)............................. H-4in. Horizontal........Up (Summer).......................... H~4in. Horizontal...........Down (Winter)......................... Hin. Horizontal...........Down (Winter)........................1)4in. Horizontal...........Down (Winter)...........................4in. Horizontal...........Down fWinter)...........................8in. Horizontal...........Down (Summer)...................... Hin. Horizontal___ -..Down (Summer).................... 1)4in. Horizontal...........Down (Summer)........................ 4in. Sloping, 45......Up (Winter)............... . .H~4 in. Sloping, 45.........Down (Summer)...................H~4in. Vertical................Horiz. (Winter)..................... H-4in. Vertical............... Horiz. (Summer).............H~4 in. AIR SURFACES0 Still Air 15 mph Wind 7)4 mph Wind See Table 1--Section A Position Heat Flow Horizontal............................................................ Up Up Sloping (45)................................................Up Vertical....................................................Horizontal Sloping (45)..................................................Down Horizontal....................................................... Down Any Position--Any Direction (For Winter)....... Any Position--Any Direction (For Summer) ... building BOARD41 Boards, Panels, Sheathing, Etc. building PAPER FLOORING materials 5 Blanket and Bait Asbestos-cement board............................................ Asbestos-cement board...................................H in. Gypsum or plaster board............................. $ in. Gypsum or plaster board..............................)4 in. Plywood...................................................................... Plywood......................................... ......... H in. Plywood............................................................H in. Plywood............................................................ )4 in. Plywood or Wood Panels..............................H in. . jWood fiber board, laminated or homogeneous. Wood fiber--hardboard type................................... Wood fiber--hardboard type........................ H in. Wood--fir or pine sheathing..................... in. Wood--fir or pine........................... 1)4 in.. 50 -50 34 34 34 34 31 65 65 Vapor--permeable felt............ ........................ Vapor--seal, 2 layers of mopped 16 lb felt.. Vapor--seal, plastic film.................................. Asphalt tile............................................................ )4in. Carpet and fibrous pad........................................... Carpet and rubber pad............................................ Ceramic tile............. l in Cork tile.................... Cork tile.................. U in Felt, flooring.................. ...................................... Floor tile or linoleum--av. value.......................)4in. Linoleum................................................................ )4in. Plywood subfloor......... ............... 1 H in*. Rubber or plastic tile...........................................Hin. lerrazzo.................. j Wood subfloor .................. in Wood, hardwood finish........................................ Hin. Cotton fiber.............................. Mineral wool, fibrous form, processed from rock, slag, or glass.. Wood fiber............ ' Wood fiber, multilayer, stitched expanding...... 1.5-4.0 3.2-3.6 1.5-2.0 1.18 1.28 0.98 0.87 0.81 0.80 1.18 1.071.01 1.11 1.12 1.03 1.16 0.85 0.78 1.02 1.15 1.23 1.25 0.85 0.93 0.99 0.90 0.89 0.97 0.86 1.63 1.60 1.46 1.32 1.08 6.00 4.00 0.61 0.62 0.68 0.76 0.92 0.17 0.25 33. 3.10 2.25 0.03 0.32 0.45 3.20 0.31 2.12 0.47 1.60 0.63 1.07 0.94 0.42 2.38 0.50 2.00 1.40 0.72 5.60 0.18 1.02 0.98 0.49 2.03 16.70 8.35 24.80 0.48 0.81 12.50 3.60 16.70 20.00 12.00 1.28 42.40 12.50 1.02 1.47 0.27 3.70 0.25 4.00 0.27 3.70