Air Ducts - Sizing

Required duct area vs. air flow.

Air Flow (CFM)	Air Velocity (ft/min)	Required Duct Area (sq in)
100	400	1.5
200	400	3
300	400	4.5
400	400	6
500	400	7.5
600	400	9
700	400	10.5
800	400	12
900	400	13.5
1000	400	15