System Demand Estimator
Preliminary NFPA 13 style estimate – confirm with a full hydraulic calculation.
Units
Project information
Design criteria
Turn off if you want to override density / area manually.
gpm/ft²
ft²
Sprinkler count uses 80% of this spacing for conservative estimate.
gpm
gpm
Enter as listed on sprinkler datasheet (gpm/√psi).
ft (positive if sprinklers are above the supply / test hydrant).
Internal system friction (inside building)
Override if you have calculated losses.
psi
psi
Underground & backflow
ft
Loss estimated from typical curves near system flow.
Water supply test
psi
psi
gpm