Engineering Calculators

Fire Pump Demand Calculator

The fire flow demand for the system, from your hydraulic calculation or NFPA sizing table.

Pressure needed at the hydraulically most remote (hardest to supply) point in the system.

Flooded: the water source sits above the pump (positive suction pressure). Lift: the pump must draw water up from below, e.g. a tank or reservoir.

Static pressure available at the pump suction from the flooded source.

Optional extra flow margin for future demand growth or calculation uncertainty. Leave at 0 if not needed.

Formula Reference

Flooded Suction

Prated=Pdemand−PsuctionP_{rated} = P_{demand} - P_{suction}

Suction Lift

Prated=Pdemand+(hlift×0.433)P_{rated} = P_{demand} + (h_{lift} \times 0.433)

P_rated = rated pressure (psi), P_demand = required pressure at demand point (psi), P_suction = available suction pressure (psi), h_lift = suction lift (ft).