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HEATING VENTILATING AIR CONDITIONING GUIDE 1944 Table 3. Conductivities (4) and Conductances (Q Used in Calculating Heat Loss Coefficients (U) in Tables 4 to 16 These constants are expressed in Btu per hour per square foot per degree Fahrenheit temperature difference. Conductivities (k) are per inch thickness and conductances (Q are for thickness or construction stated, not per inch thickness. MATERIAL DESCRIPTION Conductivity or Conductance Resistance (*> AIR SPACES Bounded bt ordinary uitthhtj Bounded bt aluminum ran. | Vertical*, in. or more in width..... ..... Vertical*, 5^ in. or more in width........ -- EXTERIOR FINISHES (Frame Walls); Brick Venebr,._ Stucco (l in,)...- 4 in. thick (nominal)-- Wood Shingles.., Yellow Pine Lap Siding____ INSULATING MATERIALS Aluminum Foil.___________ Bats. C0RKB0ARD._ Insulating Board... Mineral Wool.___ VgWlfTfTTTJTB See Air Spaces-- Enclosed both aides... Made from mineral or vegetable fibers or animal hair. Pure, no added binder... INTERIOR FINISHES Composition Wallsoabp-------- Gypsum Plaster........... Gypsum Board (${ nr.)______ --. Gypsum Lath ($ in.) and Plaster.. Insulating Board (V$ in.)__ ,--_____ Insulating Board Lath (M in.) and Plaster. . Insulating Board Lath (1 nr.) and Plaster Metal Lath and Plast*r_ Plywood bt.)_- Wood Lath and Plasteb-- % in. to H in. thick-- Piaster thicknega asannwH in. Plain or decorated______________ Plaster thickness assumed H 'n Plaster thickness assumed H in. Plaster thickness wmimwi ^ in. Plain or decorated..... ............. ....... 0.27 0.27 0X0 0X3 0X7 0.48 0.50 3X0 MASONRY MATERIALS Brick.____ ____ _________ Brick... Brick- Cement Mortar 3 m. Clay tile (hollow)-- 4 in. Clay tile (hollow)-- 6 in. Clay tile (hollow)-- 8 nr. Clay tile (hollow)-- 10 in. Clay tile (hollow).. 12 in. Clay tile (hollow)-- . 16 in. Clay tile (hollow)--. ; Concrete....... ..... . Concrete. 3 in. Concrete blocks... 4 in. Concrete blocks- . 8 in. Concrete blocks.--. 12 in. Concrete bwm, 8 in. Concrete blocks........ 12 in. Concrete blocks.. 8 in. Concrete blocks.. 12 in. Concrete blocks... Gypsum pzbbr concrete... 3 in. Gypsum ttt.b 4 in. Gypsum tilk StuccoTile AND TeRRASZO-- Adobe._____ Common___ 3.56 --5.00 6.20 12.00 light weight aggregate*..... Sand and gravel aggregate. Hollow, cinder aggregate--. Hallow, cinder aggregat Hollow, gravel aggregate. H..ovll.ovwn, gravel nawggviregate.. Hollow, cinder aggregate Hollow, cinder aggregateHito^illio--w, light_wUei-gLhrtra.g__g_regate* Hollow, light weight aggregate*--------------87H per cent gypsum and 12K per cent wood chips..'.______ --________ __ _______ Hollow.-- Hollow--..................................... --...................... For flooring... 2.50 12.00 12X0 12.00 (O (x)-(f) 1.10 0.91 0.46 2.17 0.44 0.08 11X8 0.78 0.78 3.70 2.4 4.40 *2x0 1.28 1.00 0.64 0.60 0X8 0.40 0X1 1.28 1.00 1.00 0.80 0.60 0X3 0X0 0.47 0.61 0.46 3.70 , 3.70 3X3 . 3.03 3.70 2.08 2.00 0.30 0X7 0.42 1X2 1.67 3.18 0.23 0.47 0.40 0.28 0.20 0.11 0.08 0.78 1.00 1.57 1.67 1.72 2.50 3.23 0.40 0.08 0.78 1.00 1.00 1.25 1.66 1.88 2.00 2.13 0.60 1.64 2.18 0.08 0.08 Conductance values for horizontal air spaces depend on whether the heat flow is upward or downward, but in most cases it is sufficiently accurate to use the same values for horizontal as for vertical air spaces. *Expanded slag, burned clay or pumice. 98 CHAPTER 4. HEAT TRANSMISSION COEFFICIENTS Table 3. Conductivities (k) and Conductances (C) Used in Calculating Heat Loss Coefficients (/) in Tables 4 to 16--Concluded These constants are expressed in Btu per hour Per square foot Per degree Fahrenheit temperature difference. Conductivities (A) are per inch thickness and conductances (Q arefor thickness or construction stated, not per inch thickness. MATERIAL description Conductivity OB Conductance Resistance (W (O (*)(*) ROOFING MATERIALS Asbestos Shingles--------------------------- Asphalt Shingles----...................... Buh/t-up booting --.--.--------- Slate-------------- .------------------------ --- ....... ....... ioToo 6X0 6X0 3X3 6X0 ~i*X8 SHEATHING Gypsum (H in.)---------------- --------------Insulating Board (Hfr in.)------------ --------------------------------------------------- - __ -- Fib, plus building paper------------------ Actual thicknesB H in.------------------------- SURFACES 15 MPH WIND VELOCITY--------- Ordinary non-reflective materials, vertical-- OrrliTr*Yy non-reflective materials, vertical-- WOODS Fib sheathing (1 in.) building paper and Yellow Pot lap siding-------- Yellow Pine or Feb....... ..................... -------------------- ----------------~ 1.1*5 0.80 2X2 *086 1.65 6.00 0X0 0.17 0.15 0.28 0.15 0.10 0.78 0X5 2X7 0X9 0.98 1.16 2.00 0X7 1X5 oo 52 coefficients involving upward heat flow through horizontal and sloping air spaces bounded on one side by aluminum foil applied to plasterboard, as for similar vertical' air spaces. As already stated, a conductance value of 1.10 was similarly used in all cases for calculating the coefficients of construction involving vertical, horizontal and sloping Air spaces bounded on both sides by ordinary building materials. PRACTICAL COEFFICIENTS For practical purposes it is necessary to have average coefficients that may be applied to various materials and types of construction without the necessity of making tests on the individual material or combination of materials. In Table 2 coefficients are given for a group of materials which have been selected from various sources. Wherever possible the proper ties of material and conditions of. tests are given. However, in selecting and applying these values to any construction a "reasonable amount of caution is necessary; variations will be found in the coefficients for the same materials, which may be partly due to different test methods used, but which are largely due to variations in materials. The coefficients which have been used for the calculation of over-all coefficients are given in Table 3. It should be recognized in these tables of calculated coefficients that space limitations will not permit the inclusion of all the combinations of materials that are used in building construction and the varied applications of insulating materials to these'constructions. Typical examples are given 99