Document B8K1xq5xYXDmYV3oKjgq7wE0o

180 CHAPTER 9 1952 Guide .Tabus 5. Conductivities (k) and Condctances (C) Used in Calculating Heat Transmission Coefficients (U) in. Tables 6 to 19 ' These constants are expressed in Btu per (how) (square foot) (Fahrenheit degree temperature difference). Conductivities (k) are per tnek thickness and conductances (C) are for thickness or construction stated, not per nek thickness Conductivity] . . OB [Conductance! Resistance Material Description o(k) 0 [Per Inch Thick ness For Thicki, ness Listed G) G) AIR SPACES Bounded bt Obdznabt Ma- ipntAtu........................................... . Bounded btAluminum Foil. Vertical, 3 in. or more in width. Vertical, I in. or more in width. 1.10 0.46 0.91 2.17 EXTERIOR FINISHES (Fbamb Walie) Bbick Veneer ...................... Stucco (1 in.).................. Wood Shingles....................... Yellow Pine Lap Sidinq. .. 4 in. thick (nominal).. 2.27 0.08 0.78 0.78 INSULATING MATERIALS Aluminum Foil...................... Bats and Blankets............. COBKBOABD................................... Insulating Board. .............. Mineral Wool........................ Vebmiculitb........................ See Air Spaces....................................... Made from mineral or'vegetable fiber or animal hair, enclosed or open .i... Pure, no added binder.:..... .............. .Vegetable fiber..........:...... .................... Fiber made from rock, slag or glass... Expanded............................................... 0.27 0.30 0.33 0.27 0.48 3.70 3.33 3.03 3.70 2.08 INTERIOR FINISHES Composition Wallboabd -- Gypsum Plastbb...................... Gypsum Boabd (} in.)........... Gypsum Lath (j in.) and Plastbb............................. Insulating Boabd (J in.)___ Insulating Boabd Lath (i IN.) AND PLASTEB............. Inbulatxng Boabd Lath (1 in.) and Plastbb....___ Metal Lath and Plaster ... Plywood (3 in.)............... . Wood Lath and Plastbb. A in* to 3 in. thick. . plain or decorated... Plaster thickness assumed 4 in........... Plain or decorated........................... Plaster thickness assumed 4 in. . Plaster thickness assumed | inA. Plaster thickness assumed | in. .. Plain or decorated...................... . 0.50 3.70 2.4 0.66 0.60 0.31 4.40 2.12' 2.50 0.27 0.42 1.52 1.67 3.18 0.23 0.47 0.40 MASONRY MATERIALS Bbick....................................... . Bbick....................................... Bbick............... ........................ Cement Hobtab. '...... ........ 3 in. Clay Txlb (Hollow) 4 in. Clay Tile (Hollow) 6 in. Clay Tile (Hollow) 8 in. Clay Tile (Hollow) 10 in. Clay Tile (Hollow) 12 in. Clay Tile (Hollow) 16 in. Clay Tilb (Hollow) Concrete............................... Concrete.............................. 3 in. Concrete Blocks ... 4 in. Concrete Blocks ... 8 m. Concrete Blocks ... 12 in. Concrete Blocks ... 8 in. Concrete Blocks ... 12 in. Concrete Blocks ... 8 in. Concrete Blocks .:. 12 in. Concrete Blocks ... Gypsum Fiber Concrete. . 3 in. Gypsum Tilb............... 4 in. Gypsum Tile............... Stucco..................................... Tile and Tebbazzo............. Stone...................................... Adobe, assumed 4 in. thick............ Common, assumed 4 in. thick............ Face, assumed 4 in. thick.................... light weight aggregate^............... ..... Sand and gravel aggregate................. Hollow, cinder aggregate...................... Hollow, cinder aggregate...................... Hollow, gravel aggregate..................... Hollow gravel aggregate...................... . Hollow, cinder aggregate.................... . Hollow, cinder aggregate.........*......... Hollow, light weight aggregate!"....... Hollow, light weight aggregator.......... 874 percent gypsum and 124 percent wood chips..... ................................ Hollow.................................................. Hollow................................................... For flooring........................................... 2.50 12.00 1.66 12.50 12.00 12.50 0.89 21..2; 5 1.28 1.00 0.64 0.60 0.58 0.40 0.31 i.: 1.00 1.00 0.80 0.60 0.53 0.50 0.47 0.61 0.46 0.40 0.08 0.60 0.08 0.08 0.08 1.12 0.80 0.43 0.78 1.00 1.67 1.67 1.73 2.50 3.23 0.78 1.00 1.00 1.25 1.66 1.88 2.00 2.13 1.64 2.18 Conductance values for horizontal air spaces depend on whether the heat flow is upward or downward, but in mast cases it is sufficiently accurate to use thesame values for horizontal as for vertical airspaces. v- b Expanded slag, burned clay or pumice. Heat Transmission Coefficients of Building Materials 181 Table 5. Conductivities (fc) and Conductances (C) Used in Calculating Heat' Transmission Coefficients (U) in Tables 6 to 19 These constants are expressed ito Btu per (hour) (square foot) (Farhsnheit degree temperature difference.) Conductivities (i) are per tnek thickness and conductances (C) are for thickness or construction stated, not per inch thickness CpNDUCTIVITI Job ' Resistance Conductance Material Description G) G>(i). (O Per Inch Thick ness For Thick-, ness Listed: ROOFING MATERIALS Asbestos Shingles................. Asphalt Shingles................... Built-up Roofing................... Assumed thickness 4 in.:........................ Heavy Roll Roofing.. ...... Slate................................ .......... Wood Shingles........................ SHEATHING # Gtpsum (4 in.)......................... Insulating Board (<| in.)... Plywood (A in.)..................... Fib ob Yellow Pine (1 in.). Fir, Plus Building Paper .. - SURFACES Ordinary non-refleetive materials. 15 mph Wind Velocity........... Ordinary non-reflective materials, vertical.................................................... WOODS Fib Sheathing (1 in.) Build . .- i ing Papeb and Yellow Pine Lap Siding.................. Maple ob Oak.......................... Yellow Pine ob Fib............. ............. ................ : *............................... -- 10.00 _ __ -- -- 0.80 6.00 3.53 20.00 1.28 0.42 2.56 1.02 0.86 1.65 6.00 -- -- 0.10 _ -- _ 1.25 0.17 0.28 0.78 0.98 1.16 0.61 0.17 2.00 - and wall temperatures. The possibility of change in emissivity with time of exposure due to surface coatings, chemical action, deposition of dust, etc., must be considered in'selecting a material for use.10 PRACTICAL COEFFICIENTS AND THEIR USE For practical purposes it is necessary to have average coefficients that may be applied to various materials and types or construction without the necessity of making actual tests. In Table, 2 coefficients are given for a group of materials which have been selected from tests by various author-, ities. Since there is some, variation in the resulting values due to varia tions in materials and in test conditions, average values for the usual con-; ditions encountered in building practice have been selected and listed in Table 5. These coefficients were used in the calculation of overall coeffi cients given in Tables 6 to 19. These tables constitute typical examples of combinations frequently Used, but any special constriictions not given can be computed by the use of the conductivity or conductance values in Table 2 and the fundamental heat transfer formulas. Caution The user should realize that the average conductivity and conductance values given in Tables 2 or 5 do not necessarily apply to all products of the same general description. In using these values, judgment should be exer cised with regard to the extent to which the product (either as received or as