Document 4amN66QDJaJpVByM2ro7M3ekQ

212 CHAPTER 9 1958 Guide 18.Table Coefficients of Transmission (U) of Windows, Skylights and Glass Block Walls Coefficients ore expressed in Blu per (hour) (square foot) (Fahrenheit degree difference in temperature between UU air on the two sides). Those for outdoor exposures are based upon the fallowing outdoor conditions: 0 P air temperature, dear skies, no solar radiation, and 16 mph outdoor wind velocity. Section A--Vertical Glass Sheetb Number of Sheets One Air space, inches ......................... Outdoor exposure....................... Indoor exposure.......................... None 1.13 0.75 H 0.61 0.50 Two H 0.55 0.46 la 0.53 0.45 H 0.41 0.38 Three 0.36 0.33 1 0.34 0.32 Section B--Horizontal Glass Sheets Heat Flow Up Heat Flow Down Number of Sheets One 1.40 0.96 H 0.70 0.59 Two H 0.66 0.56 1* 0.63 0.56 One % 0.60 ' 0.43 Two _% 1* 0.39 0.38 Section C--Walls op Hollow Glass Block Description Outdoor Exposure 7% x 7iH x 3% in. thick with glass fiber dividing the cavity................. 11% x 11% x 3% in. thick with glass fiber dividing the cavity............. 0.60 0.56. 0.53d 0.48 0.44 Indoor Partition 0.46 n 0.44 0.40 0.38 0.36 Section D--Approximate Application Factors fob Windows Multiply Flat Glass U Values by These Factors Window Description Single Glass Percent Glass1 Factor Double Glass0 Percent Glass1 Factor Windows with Stobm' Bash* >' Percent Glass* s, Factors. 100 1.00 100 1.00 >' 80 0.90 80 0.95 80 0.80iA 60 0.80 60 0.85 60 0.80l7, 80 1.00 *80 1.20 80 1.00bd 80 1.10 so 1.30 80 1.10 p " (See text p. 211.) i-V * For 1 in. or greater. b See Chapter 13, Table 14 and 15 for summer load. . ft; e See Chapter 13, Table 14,15 and 16 for summer load. " d From unpublished data recommended by ASHAE Tech. Adv. Comm, on Heat Flow Through Fenestra tion. * Unit type double glazing (two lights or panes in same opening). * Use with U values for two sheets with 1 in. air space. ' * Based on area of exposed portion of sash; does not include frame or portions of sash concealed by ft*?** b For metal storm aash or metal sash with attached storm pane. ' Tables 13-B and 14-B show values of U for summer calculations and.&o outside wind velocity of 7.5 mph. Tables 11, 12 and 15 show values ofV for both winter and summer. Tables 9 through 12 are for indoor U valueS and are based upon still air. All roof coefficient tables also take intoAfj count the direction of heat flow. Care must be exercised in selecting J Heat Transmission Coefficients of Building Materials 213 19. (U)Table Coefficients of Transmission of Solid Wood Doors Coefficient* are expreeeed in Bin per (hour) (square fool} iffahrenheit degree difference in temperature bettce'en the air on the two eideet. and are bnerA .TM- ,,,, ---- .--J--*---. Nominal Thickness Inches Actual Thickness .Inches ua * Exposed Door Xje. 0 With Glass Stobu Doob i if if fi 0.64 1A 0.55 1A 0.49 if 0.48 0.37 0.34 0.32 0.31 2 25 3 if 2f 2f 0.43 0.36 0.31 0.28 0,26 0.23 50 percent glass and thin wood panels. UTable 20. Conversion Table for Wall Coefficient for Various Wind Velocities calculated for 15 mph wind velocity. table which applies to the design conditions. tav,le js used for summer values of U for other wind velocities. ...W. he Tab_le 20v swhohwicshcocmanpabreaitnive ti values, it is necessary to enter the table ,m this table should tarpolated between 5 and 10 mph. Any value taken iro be rounded to two significant figures.