Convert round to rectangular, or rectangular to round, duct sizes for HVAC applications.
This chart is based on the “duct friction loss formula”; rectangular dimensions & airflow volume adapted to the equal friction loss method of sizing ventilation duct systems. Approx. friction loss of 0.8″ water gauge / 100 ft duct (6.6 Pa/m).
Bold: popular “standard” (available from Home Depot, Lowe’s, and other major hardware stores) rectangular duct sizes for conversion from Futuro Futuro standard 6″ round ducts.
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