Find the loss coefficient and pressure loss of common duct fittings: elbows, expansions, contractions, entries, exits and supply or return tees and wyes, in round or rectangular duct. Add fittings to a list to total their pressure loss.
Roughness only changes the friction part of smooth elbows and gradual transitions.
Smooth radius elbow
- Velocity
- – m/s
- Velocity, downstream
- – m/s
- Velocity pressure
- – Pa
- Loss coefficient C
- –
- Pressure loss
- – Pa
Fitting list
Add fittings above to total their pressure loss. Add the total to the straight duct loss from the duct sizing tool for the run's pressure drop.
| Fitting | Qty | C | Each, Pa | Total, Pa | |
|---|---|---|---|---|---|
| Total fitting loss | – Pa | ||||
Loss coefficients: Rennels & Hudson, Pipe Flow (2012) for elbows, entries, exits and transitions; Crane, Flow of Fluids TP-410 (2009) for tees and wyes; as coded in the open-source fluids library by Caleb Bell (MIT licence). Rectangular ducts use the round-duct equations with the area ratio, the width in the plane of the turn and the hydraulic diameter, so treat their results as estimates.