Duct sizing and pressure drop calculator

Draw a branched extraction network with one fan. Enter the airflow at each hood, duct dimensions and component loss data. The designer calculates velocities, pressure losses, the critical flow path and required pressure duty.

Calculation basis

Duct friction follows Darcy–Weisbach with a Colebrook Darcy friction factor for turbulent flow. Fitting losses use supplied K values, with component losses included separately. SI units include m³/h, m/s, mm and Pa.

The model uses prescribed airflow and a tree network without loops. It does not solve fan-curve operating points, multiple fans or hood capture effectiveness. Review the project inputs and application boundaries.