Document 82mmoBdKb1O2BNaRX24Zw2rd

190 CHAPTER 9 1957 Guide s Table 8. Coefficients of Transmission (U) of Masonry Cavity Walls* loegicienta art sxpressed t'n Btu per {hour) (square foot) (Fahrenheit degree difference in temperature between * the air on the two sides), and are based on an outside wind velocity of 15 mph. Example Example of Substitution Resistances ttscd are given below in this Resistances used are given below tn tAa-bi.l1e- o--r tn mTa-b1.1le. 3 o--r 4/ table or tn Table 3 or 4. Construction Resistance (R) 1. Outside surface (15 mph wind) 0.17 . 2. Common brick (4 in.) (av. R.) 0.76' 3. Air spaceb..... ........................... 0.97 4. Concrete block (gravel agg.) (4 in.)....................................0.71 5. Airspace..................................0.97 6. Gypsum lath (% in.).............. 0.39 7. Plas. (H. wt. agg.) Vi in...........0.39 8. Inside surface (still air)......... 0.6S Total resistance.................... 4-90 U = \/R =* 1/4.90 =........... 0.20 See value 0.20 in bold face type in table below. To Adjust U Values for Construction with Added Insulation* between Inner and Outer 16...Tiers or between Furring Strips, See Table Replace item 4 with 8 in. concrete block and items 0 and 7 with % in. plas. (sand agg.) applied directly to concrete block. Total resistance......................... 4.90 Deduct 4. Concrete block (gravel agg.) 4 in.........................................0.71 5. Airspace.................................. 0.57 6. Gypsum lath (% in.).......... O.St 7. Plas. (It. wt. agg.) Vi in.......O.St Resistance deducted....... t-SS Difference........................... 9.63 Add , 4. Concrete block (gravel agg.) Sin........................................ 1.11 7. Plas. (sand agg.) H in......... 0.11 Resistance added.............. 7*33 Total resistance =..............3*8 U = \/R = 1/3.80 =......... 0.28 Exterior CONSTRUCTION Inner Section Interior Finish Insul. Metal Gypsum Bd. Lath Plas % AND n Lath (H in.) Lath and in. on Wall. IN. Plas. and Vi in. Plas. U-V4in. Plas. on Fur on Furring on Fur- ring ri NO TaJ M *0 C w W : tM* .J *< 0.39 0.47 -co t*e * . ta M i TJ W *0 N a" Z 0.41 0.64 1.4S 1.59 0.49 . UU Face brick (4 in.) Concrete block (4 in.) (Gravel agg.)............. (Cinder agg.).............. (Lt. wt. agg.)............. 0.44 Common brick (4 in.). Clay tile (4 in.)............ Common brick (4 in.) 0.80 Concrete block (gravel agg.) (4 .in.) 0.71 Concrete block (4 in.) . (Gravel agg.)............ (Cinder agg.).............. (Lt. wt. agg.)............. Common brick (4 in.).. Clay tile (4 in.)............. 0 1*50.71 1.11 1.60 0.34 0.30 0.27 0.32 0.29 0.26 0.30 0.27 0.24 0.25 0.22 0.21 0.23 0.21 0.19 0. 0.21 0. 0. 0.21 0.19 0.22 0.20 0.19 0.19 0.17 0.16 0.18 0.17 0.16 0.23^ 0.*l . 0.80 0.33 0.32 0.29 0.24 0.22 0.23 0.23 0.21 0.18 0.18 o.v% 1.11 0.30 0.29 0.27 0.22 0.21 0.21 0.21 0.20 0.17 0.17 41 ;* oM0.71 1:11 1.60 0.30 0.27 0.25 0.29 0.28 0.24 0.27 0.25 0.22 0.23 0.21 0.19 0.21 0.19 0.18 0.22 0.20 0.19 0.21 0.20 0.18 0.20 0.19 0.18 0.18 0.16 0.15 0.17 0.16 0.15 0.?0.I8 0.80 0.30 0.29 0.27 0.22 0.21 0.21 0.21 0.20 0.17 0.17 1.11 0.27 0.26 0.25 0.21 0.19 0.20 0.20 0.19 0.16 0.16 o.gS' T-S*! Concrete block - . (cinder agg.) (4 in.) Concrete block (4 in.) (Gravel agg.)............... (Cinder agg.)............... (Lt. wt. agg.)............... Common brick (4 in.)... 0.17 0.16 0.16 0.16 0.15 0.14 0.16 0.1 Clay tile (4 in.)............... 0.16 0.15 * See text section Calculating Overall Coefficients for basis of calculations. b To adjust U values see note just above this table. * If insulation is to be used in the cavity it should be a water resistant type. Heat Transmission Coefficients of Building Materials 191 Table 9. Coefficients of Transmission (U) of Frame Partitions or Interior Walls* Coefficients are expressed in Btu per (how) (square foot) (Fahrenheit degree difference in tempcratwe between the atr on the two sides), and are traced on etm air (no wind) conditions on both sidss. ^fl Example Resistances used are given below in fAi* table or in Table 3 or 4* Construction Resistance (R) 1. Surface (still air)........................0.68 2. Gypsum bd. (H in.)..................0.39 3. Airspace.................................... 0.P7 4. Gypsum wall board (% in.).. 0.39 5. Surface (still air)........................ 0.68 Total resistance.................... t.97 U = 1/R = 1/9.97............ 0.34 See value 0.34 in bold face type in table below. Example of Substitution Resistances used are given below in this table or in Table 3 or 1. Replace item 2 with wood fiber hardtx>ard (X in). Total resistance............... ........... t.97 Deduct 2. Gypsum wall board(H in.)... O.St Difference.................................t.66 Add 2. Hardboard (H in*).....................0.18 Total resistance..................... t.83 U = 1/R = l/t.83 =............0.35 UTo Adjust Values for Construction with Added Insulation between Mem bers, See Table 16. Type or Interior Finish Single Partition (Finish on Onlt One Side or Studs) Double Partition (Finish on Both Sides or Studs) Material R 17 V Gypsum bd. (H in.)............................................................. Gypsum lath (H in.) and Vi in. plas. (lt. wt. agg.)......................... Gypsum lath (H in.) and Vi in- pl*ft, (*wid H in. plas. (It. wt. agg.)............................................. Metal lath and H in. plas. (sand agg/)............................................ Insul. bd. (44 in.) Insul. bd. lath (H in.) and Vi plas. (sand agg.)................................ Plywood: (H in.)...................... (% in.)................................................... Wood panels (94 in.) Wood-lath and J4 in. p1*s, Mgg ) Sheet metal oanels Glass and glass blocks.................... O.St 0.64 0.41 0.47 0.1S 1.43 I.St 0.31 0.47 0.63 0.94 0.40 0 b text section Calculating Overall Coefficients for basis of calculations, o adjust V values see note just above this table. 0.60 0.50 0.56 0.55 0.67 0.36 0.35 0.60 0.55 0.50 0.43 0.57 0.74 0.34 0.32 0.31 0.39 0.19 0.19 0.34 0.31 0.28 0.24 0.32 0.43 See Table 20 tion of heat flow. Each part is based on temperature conditions considered generally appropriate for the case. c Any and all 1} values are based on a series of assumptions as to nominal sh'^t6nS^CI3' Common variations in conditions, materials, workmanP-etc- ca.n introduce much greater variations in U values than the varia- feJJ? resMlting from the assumed mean temperatures and temperature difsienifi68 c'escr*f>ecf; From this it is also clear that the use of more than two dcShf.i811*' Sures in stating a U value is assuming more precision than can wy ^. Three significant figures are used in Table 16 merely as a k. , . . reducing cumulative errors when the table is used several times accur t n a 8TM^e result. It should not be assumed that the figures are Tahio ir' ?ver`a^' t three significant figures. Also, a result taken from ro should always be rounded off to two significant figures. (Text continued on page 201)