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( i <br /> �� � <br /> � �� � <br /> � <br /> F R A N K L I N %'=� '=��"th Avenue P�i 425 C•L7-JJ2= <br /> ENGINEERING ��������� � ����`��`;-�`�� <br /> Y �4:1an�7 L;'A 930'�� 'v�cC'�a�klicer��crn <br /> h4EC�—A�ICAL CGP.SULTIVG <br /> U-value Calculat�ori for "Vented" T-bar Ceiling with Light Fixtures <br /> R-19 Batts R-25 Batts <br /> U-value Area UA U-value Area UA <br /> Ven� Gap 1.13 0.2516 0.330 Vent Gap 1.13 0.2916 0.330 <br /> Insulation R-19 0.05 93.0084 4.650 Insulation R-25 0.04 93.0084 3.720 <br /> Total UP, 4.980 Total UA 4.050 <br /> Average U-value = U,= UA/A U.= 0.053 Average U-value = U�= UA/A U,= 0.043 <br /> R-19 batts R-25 batts <br /> R-30 Batts R-38 Batts <br /> U-value Area UA U-value Area UA <br /> Vent Gap 1.13 0.2916 0.330 Vent Gap 1.13 0.2976 0.330 <br /> Insulation R-30 0.034 93.0084 3.162 Insulation R-38 0.026 93.0084 2.418 <br /> Total UA 3.492 Total UA 2.748 <br /> Average U-value = U,= UA/A U,= 0.037 Average U-value = U�= UA/A U,= 0.029 <br /> R30 batts R-38 batts <br /> Background Calculations <br /> Vent Gap <br /> Size: 7/8"wide by 48" long U-value of vent gap: <br /> Area= 7/8 x 48= 42 in2 Assume R=0.88, 1/R=U=1.13 <br /> 42 in2/144 inZ= 0.2916 ft2 <br /> Vent Gap Area=0.2916 ftZ U-value of Vent Ga = 1.13 <br /> Light Fixtures Insulation <br /> Assume: Area of insulation <br /> 112 watts/tixtz re _ y3.3 ftZ = area of Light Fixtures-area of Vent Gap <br /> 12 wads�ft Area of insulation = 93.3- 02916 <br /> 1 Li ht Fixture er 93.3 tt' Insulation Area=93.0084 tt <br /> _; <br /> �'' <br /> � <br />