Plenum Sizing Velocity Calculator
Plenum and trunk sizing starts from airflow and target velocity. The calculator converts CFM into required area, round equivalent and rectangular dimensions.
plenum sizing velocity calculator duct size calculator by cfm rectangular duct size
Area from airflow
A = Q / v
Rectangular aspect ratio
H = sqrt(A / aspect); W = aspect * H
Static-pressure follow-up
After selecting plenum and branch sizes, carry straight-duct and fitting losses into the external static pressure budget.
Related pages
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