Axial Upblast Roof Exhaust Fan Assembly Unassembled Drive Type Belt Drive Blade Diameter 54 in Base Diameter Not Applicable Base Length 66 1/2 in Base Width 66 1/2 in Base Shape Square Maximum Airflow 50 958 cfm Minimum Airflow 17 378 cfm Maximum Motor Horsepower 7 1/2 hp Minimum Motor Horsepower 2 hp Maximum Motor Speed 496 RPM Minimum Motor Speed 291 RPM Maximum Static Pressure 1/2 in wc For High-Static Pressure Applications No For Air Type Clean Air