Pump Discharge Pressure (PDP) Calculator

Quick, field-friendly PDP estimate for training and preplans. Supports a common supply line feeding multiple identical attack lines. Formula: PDP = NP + FL(supply) + FL(attack) + Appliance + Elevation.

Inputs

Nozzle Pressure (NP) (psi)

Typical: Fog 100 / Smooth bore handline 50 / Master stream 80–100

Attack flow (GPM) per line

Number of attack lines

Common Supply Line (optional)

Supply diameter

Supply length (ft)

Attack Line

Attack diameter

Attack length (ft)

Appliance Loss (psi)

Wye / Gated Wye (10)

Standpipe / FDC friction (25)

Master stream device (10)

Other minor appliance (5)

Custom appliance loss (psi)

Elevation gain (+ft) / loss (-ft)

Uses 0.434 psi per ft (water head).

Results

ESTIMATED PDP

—

Suggested setting (rounded up): —

Total flow

—

Elevation pressure

—

Breakdown

NP—

Friction Loss (Supply)—

Friction Loss (Attack)—

Appliance Loss—

Elevation—

PDP—

Quick Links (use with this)

Friction Loss Fire Flow Hydrant Flow SCBA Air Time MAYDAY LUNAR

Note

This calculator provides training estimates. Local SOP/SOG, nozzle specifications, hose conditions, and appliance characteristics can affect actual pressures.