Document 8Kp7kevwd5mX8M229mNOV0gK

202 CHAPTER: 9 ; '1958.` GuideT' Table 14B. Coefficients of Transmission (U) of Wood or Metal Construction Flat Roofs and Ceilings* (Concluded). DIRECTION OF FLOW DOWNWARD FLOW (SUMMER CONDITIONS) Ttpe op Deck Built-up Roof in All Cases TYPE OF CEILING Insulation Added on Top of Deck =. G a*- -- a0-2*0- *0 ! O None Gypsum Bd. (96 in.) and Plas. Metal g- Lath and Plas. SiS s a a ad 5 X O ad 3 i! - ES < 3 S 2*3 < 0 a0 s 2 2 is0ac9# .3 u cd .5^3 d.2< 00 Acoustical Tilb-^ On Furring- On Gyp^ sum Bd:'1 (96-ihl) J3 ' .5 c a 'X X x l 0.33 0.64 0.41 0.47 0.13 1.47 U9 1.78 1.51 3.10 Material *C R V V u V V U V . -V V V U ' Preformed slabs-- wood fiber and ce ment binder 2 in. 3.60 3 in. 5.40 None None Flat Metal Reef Deck None 0.72 . 0.36 0.24 0.19 0.15 0.12 - _ 1.39 3.78 4-27 6.36 6.67 8.33 0.20 0.14 0.67 0.35 0.23 0.18 0.15 0.12 0.10 0.15 0.14 0.12 0.11 0.33 0.23 0.17 0.14 0.12 0.10 0.09 0.30 0.21 0.16 .0.13 0.12 0.10 0.09 0.15 0.12 0.32 0.22 0.17 0.14 0.12 0.10 0.09 0.15 0.15 0.13 0.12 0.12 0.10 6.31 0.35 0.24 0.22 0.24 0.18 0.17 0. IS 0.14 0.14 0.14 0.12 0.12 0.12 0.11 0.10 0.UJ 0.09 0.09 0.09 0.08 0.13 0.12 0.13 0.12' 0.11 0.10 0.10 0.10: 0.26 0.22 0.24 oih'i 0.19 0.1/ 0. It 0.-i6` 0.15 0.14 0.14 0:130.12 0.12 0.12 0.11. 0.11 0.11 0.1C '0.10 0.09 0.09 0.09 0.090.08 0.08 0.08 0.08 * See text section Calculating Overall Coefficients for basis of calculations. b To adjust U values see note just above this table. c Wood deck 1, 2, and 3 in. is assumed to be ductivity k is assumed to be 0.80. 156. and 256 in. thick, respectively. The thermal con-;, -- d If a vapor barrier is used beneath roof insulation it will have a negligible effect on the U value. For,- information on vapor barrier requirements see Chapter 10, Moisture in Building Construction. .*?- To use Table 16: i- . 1. Find in Column 1 of the appropriate table the value for U obtained from Tables 5 through 15. 2. If there is a column which exactly corresponds to the condition for which you i, desire the U value, read the answer in this column, opposite the Column 1 value.'.L Interpolate if necessary. 3. If there is no column which fully corresponds to the condition for which yoiijj desire the U value, then obtain the answer by means of two or more steps--eaclTj time using the value obtained in one step to reenter the same table through ColumB^r 1. In this way U values may be obtained for combinations of insulation in the fraifl'. ing space. /; C; EXAMPLES OF THE USE OF TABLE 16 ;v.r Example $: Find the coefficient of transmission U\ of the frame wall shown example at the top of Table 5: (a) With 2-inch blanket fibrous insulation between the studs and in contact wife the gypsum lath and, - (b) With aluminum-foil-backed gypsum lath. . 'I Solution: According to Table 5, the U value for this construction with no insul'?^ tion in the air space is 0.24. Referring to Table 16 Part A for walls, it is found th>* corresponding to the value 0.24 in Column 1, the coefficient for conditions (a) a?" (b) are: (a) In Column 4, find Ui = 0.087. Use 0.09. (b) From Table 3, Section C, the effective emissivity E of aluminum foil is 0$^: In Column 8 find U, = 0.173. Use 0.17. .T* (Text continued on p. 208.) Heat'Transmission Coefficients of Building Materials 203 Table 15. Coefficients of Transmission (U) of Pitched Roofs*.b Coefficient* ore expressed in Btu per {hover) {squarefoot) (Fahrenheit degree difference in temperature between the air on the two sides), and are based on an outside wind velocity of IS mph for heat flow upward and 7.6 mph for heat flow'downward. Example Example of Substitution Resistances used are given below in this table or in Table 3 or 4. Resistances used are given below in this table~~inTabs SSt floX) Resistance (ff, Find.../. ------- --r same construction l !1:1 oft--'Outside surface (15 mph wind) .......................... 0.27 2. Slate shingles 06 in.) 3. Building paper 0.05 0.06 4. Wood sheathing (2H* in.) 0 5. Air space*-.'..................... o.90 with heat flow down (summer conditions) Total resistance................ Deduct # 10 . Outside surface (15 mph wind)............................... Q' jj 8. Inside surface (still air).......... 0.63 Resistance deducted.......... 2.69 Total resistance............... . 3.29 U 1/R 1/3.J9................0.31 See value 0.31 in bold face type in table below. ` \ To Adjust U Values for Construction with Added Insulation between Framing Members, See Table 16. Add DWerence........................... '> 1. Outside surface (7.5 mph Air spa.c..e............................................. 0/ .3055 8. Inside surface (still air)! 0.76 Total resistance............ 3.04 * Si DIRECTION OF HEAT FLOW - UPWARD FLOW WINTER CONDITIONS 1 DOWNWARD FLOW (SUMMER CONDITIONS Rafter Space Rafter Space ,UoiI Jypb of Ceiling (Applied Directly to Roop Rafters) None.............................................................. Gypsum bd. (96 in.)...............- Gypsum lath (H in.) and Yi plas. (it* wt. Gypstfmlathi (5iin.) and V6 in. plas. (sand 1 Metaffath and it in plas. (It. wt. agg.) - Metal lath and 94 in plas. (sand agg.) . Insul. bd. (V6 in.)......................................... Insul. bd. lath and 56 in. plas. (sand agg.) Acoustical tile (H in.) on gypsum bd. (96 in.) 06 in.) on furring...................... (H in.) on gypsum bd. (96 in.) (9* in.) on furring............................... Wood lath and )i in. plas. (sand agg.) Unventilated Not to be Further | Insulated I Unventilated Not to be Further Insulated jl jl -->------t s Paper 0 0c 1" c5.S5 CO "2 1"5a 00 sS e X ou O vmu aw 0 . iS OM ii 2c a . go < 1.09 0.87 VU 0.30 0.33 0.32 0.36 0.25 0.24 0.24 0.26 0.21 0.23 0.33 ) 0.48 0.53 C 0.29 0.31 0 0.26 0.29 0.31 0.46 0.27 0.28 0 0.28 0.27 0.30 0.22 0.21 0.31. 0.34; 0.52 0.31 0.33 0.50 0.34 0.37 0.61 0.24 0.25 0.34 0.23 0.25 0.33 0.29, 0.29 _ 0.32 0.27 0.23 0.20 0.22 0.20 0.28 0.28 0.31 0.22 0.22 0.30 0.30 0.33 0.23 0.23 0 0 0 6 6 0.21 0.23 0.23 0.25 0.19 0.20 0.20 . 0.22 0.28 0.31 0.33 0.37 0.26 0.30 0.22 0.24 0.20 0.21 0.20 0.21 0.18 0.19 0.22 0.23 0.19 0.20 0.23 0.24 0.20 0.21 0 0 6 0 0.29 0.1 0.28 0.30 0