Standpipe Friction Loss
Riser elevation plus per-outlet friction.
Example
You enter
- Riser height (ft) 200
- Outlet count 1
- GPM per outlet 250
- Outlet hose length (ft) 100
- Outlet hose diameter 2.5_in
You get
- Elevation pressure 86.8 psi
- Friction (all outlets) 12.5 psi
- Per outlet (psi) 12.5
- Total 99.3 psi
Details, formula, and sources
Total = elevation (0.434 psi/ft × height) + per-outlet friction + appliance friction. Min residual at the topmost outlet 100 psi for Class I per NFPA 14 §7.10.
NFPA 14 (2024) §7.10 (Pressure Limitations) by name and section.
NFPA 14 read-only at nfpa.org/freeaccess.
Estimate. AHJ and licensed fire protection engineer govern.
Field names used by the API: riser_height_ft, outlet_count, gpm_per_outlet, outlet_length_ft, hose_diameter, elevation_psi, friction_total_psi, per_outlet_psi, total_psi
- Class I min residual 100 psi at the topmost outletNFPA 14-2024 §7.10