Backflow Preventer Pressure Loss

Pressure loss interpolated from manufacturer-published curves.

Run the calculator

Example

You enter

Device class RP
Flow (gpm) 30
Pipe size 1

You get

Pressure loss 14.8 psi

Checked against published worked examples from: Watts Regulator.

Details, formula, and sources

Formula or tableLinear interpolation of manufacturer pressure-loss curves by device class (RP / DCV / PVB / AVB) and pipe size.

Source and editionWatts Series LF909 RP (ES-LF909S) and Series 800M4QT PVB (ES-800M4QT) capacity charts; DCV and AVB are typical curves naming no product.

Free accessFree at watts.com.

What governsEstimate. AHJ and licensed plumber / gas fitter govern. Verify against the IPC / IFGC edition adopted in your jurisdiction.

API field namesdevice_class, flow_gpm, pipe_size_in, pressure_loss_psi

Curve table data/plumbing/backflow-curves.json keyed to device class and sizeWatts technical bulletins