Engineering Calculators

Fire Pump Power / Driver Sizing

Rated point only evaluates power at a single operating point — quick, but doesn't check the overload (150% flow) point. Full curve evaluates both, giving a more reliable driver size.

The operating point to evaluate power at — usually the pump's rated flow.

The pressure at that operating point — usually the pump's rated pressure.

The pump's efficiency at its rated point, from the manufacturer's curve or datasheet (typically 60-85%).

Ratio of the fluid's density to water. Leave at 1.0 for plain water.

Formula Reference

Water Horsepower

WHP=Q×H×SG3960WHP = \dfrac{Q \times H \times SG}{3960}

Brake Horsepower

BHP=WHPηBHP = \dfrac{WHP}{\eta}

Q = flow (GPM), H = head (ft, from pressure), SG = specific gravity, η = pump efficiency (fraction).