Laserfiche WebLink
� �� <br /> � �� �� <br /> �. <br /> F R A N K L I N ,,.��������,:�� ,,,-��,�� r�.,z�,��;�_:���:, , <br /> E.NGINEERING 5��"202 F�42582�-�,-�: <br /> ''.irk'�ndl'Jii 3'','1;53 h,ac��?ranc���r�rq_:,^�. <br /> ME"�fAkl.:r�L C,.'�:�U�Tlh�v <br /> U-value Calculation 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 /> Vent Gap 1.13 0.2916 0.530 Vent Gap 1.13 0.2916 0.330 <br /> Insulation R•19 0.05 53.0064 4.650 insulation R•25) 0.04 93.0084 3.720 <br /> Total UA 4.9&0 Total UA 4.OSD <br /> Average U•value= U,= UA/A U,= 0.053 Average U•v21ue= U,= UAiA U, = 0.043 <br /> R-19 batls R-25 batts <br /> R-30 Batts R-38 Batts <br /> U-value Area UA U-vaiue Area UA <br /> Vent Gap 1.13 0.2916 0.330 Vent Gap 1.13 0.2916 0.330 <br /> Insulation R-30 0.034 93.0084 3.162 Insulalion 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 inZ Assume R=0.88, 1/R=U=1.13 <br /> 42 in2/144 inZ = 0.2916 itZ <br /> � Vent Gap Area = 0.2916 ri2 U•value of Vent Ga = 1.13 <br /> Light Fixtures Insulatfon <br /> Assume: Area of insulation <br /> 112 watts/fixture _ 93.3 ttZ =area of Light Fixtures-area of Vent Gap <br /> 1.2 wattyft Area of insulation=93.3 - 0.2916 <br /> 1 Li ht Fixture er 93.3 ftZ insulation Area= 93.0064 ft' <br /> � � <br /> i � I� i <br /> \ <br />