Work out fire hydrant demand instantly with clear inputs, formula shown and shareable results.
Fire hydrant demand is the number of hydrants assumed to operate together multiplied by the flow each must deliver, and storage is that flow sustained for the required duration. Pressure at the landing valve is converted to head at 10.2 metres per bar, which is what the pump or tank height must provide.
Fire water demand
L/min = hydrants x flow per hydrant; storage litres = flow x duration
Head
Metres = bar x 10.197
Preliminary estimate only. Fire water supply, storage and pump duty must be designed by a qualified fire protection engineer to the applicable code.
L/min = hydrants x flow per hydrant; storage litres = flow x duration. Fire hydrant demand is the number of hydrants assumed to operate together multiplied by the flow each must deliver, and storage is that flow sustained for the required duration.
Codes specify it by occupancy and building size, commonly two for a modest building and four or more for large industrial premises. It is a code requirement, not an engineering judgement.
This calculator takes 4 inputs: Hydrants assumed operating, Flow per hydrant, Required duration, Pressure required at the hydrant. The pre-filled defaults are a realistic worked example — replace them with your own site or project figures.