cupolas
dayton 2rb70 gravity roof vent22 in sq base
gravity ventilator fan size 12 in width 29 in depth 29 in overall height 11 3 4 in base width 22 in base length 22 in 448 546 cfm throat velocity 0.050 in sp gravity intake 523 638 cfm throat velocity 0.050 in sp gravity relief max intake cfm throat velocity 1512 1848 construction spun aluminum br b features b ul li base length in . 22 li li base width in . 22 li li depth in . 29 li li dimension a in . 22 li li dimension b in . 29 li li dimension c in . 10 li li dimension d in . 3 1 2 li li dimension e in . li li dimension f in . li li dimension g in . li li dimension h in . li li fan size in . 12 li li item gravity ventilator li li overall height in . 11 3 4 li li width in . 29 li li recommended 12 in . fixed curb item no. 2rb76 li li recommended 8 in . fixed curb item no. 4hx39 li li construction material spun aluminum li li cfm throat velocity 0.050 in . sp gravity intake 448 546 li li cfm throat velocity 0.050 in . sp gravity relief 523 638 li li cfm throat velocity 0.100 in . sp gravity intake 633 772 li li cfm throat velocity 0.100 in . sp gravity relief 740 903 li li cfm throat velocity 0.125 in . sp gravity intake 708 863 li li cfm throat velocity 0.125 in . sp gravity relief 828 1009 li li cfm throat velocity 0.200 in . sp gravity intake 895 1092 li li cfm throat velocity 0.200 in . sp gravity relief 1047 1277 li li cfm throat velocity 0.250 in . sp gravity intake 1001 1221 li li cfm throat velocity 0.250 in . sp gravity relief 1171 1428 li li max . intake cfm throat velocity 1512 1848 li ul