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Mechanical

Duct Sizing

Sizes a duct for a target air velocity, then converts the equivalent round diameter to a rectangular section for the given aspect ratio.

Equal-velocity method · Huebscher equivalent diameter

Inputs

Results

Round duct diameter

15.6 in

Rectangular duct

21 × 10 in

Free area required
1.333 ft²
Velocity in rectangular duct
820 FPM
Duct perimeter
5.13 ft