Laserfiche WebLink
F R A N K L I N <br />ENGINEERING <br />625 Fourth Avenue <br />5wte 202 <br />Kirkland WA 980'3 <br />PH 425 627.3324 <br />FAX 425 827-6252 <br />hvac0 f rark hncn4.ccn <br />U-value Calculation for "Vented" T-bar Ceiling with Light Fixtures <br />R-19 Batts <br />U•value Area UA <br />Vent Gap 1 1.131 0.2916 0.33( <br />Insulation (R-19%1 0.051 93.0084 4.65( <br />Average U-value = U, = UA/A U. = 0.053 <br />R-19 batts <br />R-30 Batts <br />Vent Gap <br />Average U-value = U, = UA/A I U, = 0.037 <br />R-30 batts <br />Background Calculations <br />R-25 Batts <br />U-value Area UA <br />Vent Gap 1.13 0.2916 0.330 <br />Insulation R-25 0.04 93.0084 3.720 <br />Total UA 4.050 <br />Average U-value = U, = UNA U. = 0.043 <br />R-25 hatts <br />R-38 Batts <br />U-value <br />Area UA <br />Vent Gap 1,131 <br />0.2916 0.330 <br />Insulation R•38 0.0261 <br />93.0084 2.418 <br />Total UA 2.748 <br />Average U-value = U,, = UA/A <br />U. = 0.029 <br />R-36 baits <br />Vent Gap <br />Size: 7/8" wide by 48" long U•value of vent gap: <br />Area = 7/8 x 48 = 42 In Assume R-0.88, 1/R=U=1.13 <br />42 in2/144 In = 0.2916 ft' <br />Vent Gap Area = 0.2916 ft U-value of Vent Gap = 1.13 <br />s <br />Assume: <br />112 watts/fixture = 93.31t2 <br />1.2 watts/It2 <br />1 Light Fixture per 93.3 It <br />i <br />Area of insulation <br />- area cf Light Fixtures - area of Vent Gap <br />Area of Insulation = 93.3.0.2916 <br />F—Insulation Area = 93.0084 ft2 <br />