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122 CHAPTER 6 1948 Guide Table 4. Conductivities (k) and Conductances (Q Used in Calculating Heat Transmission Coefficients (U) in Tables 5 to 18 These constants are expressed in Btu per (hour) (square foot) (Fahrenheit degree temperature difference). Conductivities (k) ore Per inch thickness and conductances (C) are for thickness or construction stated, not per inch thickness. MATERIAL DESCRIPTION AIR SPACES Bounded bt ordinary materiaiHTM_ Vertical*, Vertical*, In. or more In width............... in. or more in width......_____ CoNDucnvrrr OB Conductance ( (CT Resistance TPhelcr kInnceha. For Thickness Listed (1) Xi) 1.10 v. 0.91 - 2.17 EXTERIOR FINISHES (Frame Walls) Ruinr Vrwrvb Stucco (1 in.)... Wood Rhinot.tr Yellow Pine 7,ap fimnra 2.27 038 -- 0.44 INSULATING MATERIALS Aluminum Fott. CORKBOABD Insulating Board_______ ____________ Mineral Wnm. VKRMirm.ITR Made from mineral or vegetable fiber or animal hair, enclosed or own Vegetable fiber' HTponrfoH 037 030 0.27 0.48 INTERIOR FINISHES Composition Wat.muurd Gtpsum Plaster Gtpsum Board (H in.)........................... Gtpsum Lath in.) and Plaster.... Insulating Board (V$ in ) Insulating Board Lath (M in.) and Plaster Inbulating Board Lath (1 m.) and Plaster' . Metal Lath and Pi.artrr; ._____ Plywood (% in.) ...........:.: i Wood Lath and Plaster.. Plaster thickiipss jwmmipH U in....... Raster' thickness assumed H in*....--____ Piaster thickness awimipA % in. ..... _....... Plain nr dwnrat<H 030 330 --- MASONRY MATERIALS Hwirnr Bbick_ ___ Burnr Cement Mortar - , ..... 3 m. Clat tile (hollow) 4-in. Clat tile (hollow)-.. 6 in. Clat tile (hollow) _______ 8 in. Clat tile (hollow) . .. 10 in. Clat tile (hollow) ... . 12 in. Clat ttt.r (hoi.t/iw) ............... 16 in. Clat tile (hollow) Conoretr CONCHWIT. 3 IN. Concrete RtiOnra Light weight aggregate6_____________________ 8 in. Concrete risickr 812 in. Concrete blocks___________ _ IN. CoNCBBTB BLOCKS................. ....... 12 in. Concrete blocks...____ __ _____ Gtpsum fiber concrete.._____ ___ ; 3 in. Gtpsttm ttt.r 4 IN. Gypsttm ttt.r......... Stucco....... Tile and Terraco Stone .................. Hollow, cinder aggregate........................ ......,.... Hollow, gravel- aggregate-...._________________ Hollow, Fmvpj'avvreivftt ' ............. Hollow, cinder aggregate__ __ ______________ Hollow, light weight aggregate6-. - Hollow, light weight aggregate6___ .____ ___ , 87K per cent gypsum and 12per cent wood chii................................ ........ ---- ------ 12.00 ZI 1.66 1230 12.00 1230 --... ........ 3.70 333 3.03 3.70 2.08 -- -- -- * '. --~ 3.70 0.66 : 0.60 4.40 2.12 230 2.00 030 " n, ---- 037 132 1.67 3.18 033 0.47 0.40 039 1.25 2.30 138 1.00 0.64 0.60 038 0.40 ' 031 -- -- oos --. 1.12 0.80 0.43 0.78 .1.00 ---- ---- 0.40 1.72 230 333 -- 138 1.00 0.80 0.60 0.53 047 zz . "** --. -r-- 0.78 1.00 130 135 1.66 1.88 0.61 0.46 0.60 ---- . 0.08 0.08 0.08 1.64 2.18 ---- ---- `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. kExpanded slag, burned clay or pumice. Heat Transmission Coefficients of Building Materials 123 Table 4. Conductivities (k) and Conductances :(C)vUsEb iN Calculating Heat Transmission Coefficients (E7) in Tables 5 to.18--Concluded These constants are expressed in Btu per (hour) (square foot) (Fahrenheit degree temperature difference). Conductivities (k) are Per inch thickness and conductances (O are for thickness or construction stated, not Per inch-thickness. * MATERIAL DESCRIPTION CoNDucnvmr Conductance Resistance Per Inch For Thickness Thickness (i) ' (O '(> .(*) ROOFING MATERIALS' Assumed thickness % in.---------------------------- Wood Shingles- ............... ................... :... __.._ 10.00 6.00 630 333 630 : 20.00 138 _ 0.17 _ 0.15 038 -- 0.15 0.10.- .. 0.05 1-- - 0.78 SHEATHING Gtpsum (H in.).:----------i:------- ---------------- . Fib or Yellow Pine (1 in.)____--____ Fir, plus building paper-.....:............ Actual thickness H6 in---------- -.Z-------------- -- -- , 2:82 0.42 - 2.56 ____ - 1.02 036 -- 035 237 039 0.98 1.16 SURFACES Ordinary non-reflective materials, vo-tical._ 15 MPH WIND VELOCITY------- --------------- Ordinary non-reflective materials, vertical-- 1.65 6.00 -- 0.61 0.17 WOODS Fib sheathing (1 in.) buildinq paper ....: 030 1.15 037 " 030 .135 . 2.00 ----- . transmission Ui of the insulated construction may be compared with the corresponding coefficient U without insulation. Attention is called to the necessity of applying the insulating material in accordance with the manufacturer's-specification. The engineer must carefully evaluate the economic considerations involved in the selection of an insulating material as adapted to various building constructions. : Lack of proper evaluation, or improper installation may lead to unsatisfactory results. Computed Heat Transmission Coefficients Computed over-all heat transmission coefficients of many common types of building construction are given in Tables 5 to 18, inclusive, each coefficient being identified by a serial number except in Table 18.' For example, the coefficient U of a brick-veneer, frame wall with wood sheathing and Y2 in. of plaster on gypsum lath is 0.27, (Wall No. 28-C in Table 5) and with 2 in. of blanket or bat insulation the coefficient would be 0.097 (No. 49-B in Table 6). , Example 1. Calculate the. coefficient of heat transmission U of a brick-veneer, frame wall with wood sheathing, building paper, and Yi in- plaster on 54 in. gypsum lath, based on a wind exposure of 15 mph. Also calculate the coefficient when 2. in. of bat insulation is added, leaving an air space in the wall, and correcting for framing amounting to 15 per cent of the wall area.. : Solution: Starting from the exterior, the resistances making up the total heat resistance are (1) exterior surface, (2) brick-veneer, (3) wood sheathing in. thick and building paper, (4) air space 354 in- wide, (5) 54 in- gypsum lath and plaster, (6) interior surface. Then using the values from Table 4 in Equation 4: r , x , r . r 1 1* 6.0 + 2.27 "1~ 0.86 'r 1.10 2.4 1.65