Plenum Fan Wheel Type Backward-Curved Drive Type Belt Drive Includes Drive Package Yes Assembly Unassembled Wheel Diameter 22 in Airflow @ 0.000 in SP 9 604 cfm Airflow @ 0.250 in SP 9 447 cfm Airflow @ 0.500 in SP 9 289 cfm Airflow @ 0.750 in SP 9 132 cfm Airflow @ 1.000 in SP 8 974 cfm Airflow @ 1.250 in SP 8 816 cfm Airflow @ 1.500 in SP 8 654 cfm Airflow @ 1.75 in SP 8 458 cfm Airflow @ 2.000 in SP 8 262 cfm Airflow @ 2.500 in SP 7 869 cfm Airflow @ 3.000 in SP 7 377 cfm