Duct Friction Loss Worksheet
Duct friction loss depends on airflow, size, length, equivalent fittings and roughness. Use the worksheet flow before carrying run losses into the static-pressure budget.
duct friction loss worksheet friction rate calculator manual d duct static pressure loss calculator
Straight-run relation
dp / L = f * (rho * v^2 / 2) / D_h
Rows to capture
- Enter airflow.
- Enter round diameter or rectangular dimensions.
- Add straight length.
- Add fitting equivalent length.
- Compare pressure drop and friction rate.
Static budget handoff
Run-level friction loss is not the whole system. Add filter, coil, terminals and other accessories in the static pressure calculator.
Related pages
- Duct size calculator - round and rectangular duct sizing from airflow.
- Duct friction loss calculator - run-level pressure loss from duct size and length.
- HVAC static pressure calculator - total external static pressure and blower margin.
- Grille size calculator - face velocity and free-area checks for terminals.