Fire Department Connection Calculator

FDC requirements from system type and demand.

System type served

Sprinkler demand (GPM)

Standpipe demand (GPM)

Building height (ft)

Distance to hydrant (ft)

FDC style

Tab to move between fields

Total FDC flow (GPM)

500

FDC connections needed

Inlet connections2

Required FD inlet pressure (PSI)136.7

Elevation pressure (PSI)21.7

FD pumper capacity OKYes

Hydrant distance OKYes

Check valve requiredYes

Signage typeAUTO SPKR & STANDPIPE

4" Storz sufficientYes

Recommended Connection Desc2 × 2.5" Siamese or 1 × 4" Storz

Drain Valve RequiredYes

How to Use This Calculator

Enter System type served, Sprinkler demand (GPM), and Standpipe demand (GPM).
Set Building height (ft), Distance to hydrant (ft), and FDC style.
Review Total FDC flow (GPM) and FDC connections needed.
Use Inlet connections and Required FD inlet pressure (PSI) to inform your decision.

How the result changes with Standpipe demand (GPM)

System type served: 1=Sprinkler only, 2=Standpipe only, 3=Combined, 4=Separate sprinkler + standpipe.
Sprinkler demand (GPM): Total sprinkler system flow demand from hydraulic calculations.
Standpipe demand (GPM): Standpipe system flow demand per NFPA 14.
Building height (ft): Height from FDC to highest outlet served.
Distance to hydrant (ft): Distance from FDC to nearest fire hydrant. Must be ≤100 ft per NFPA.
FDC style: 1=Wall-mounted, 2=Freestanding post, 3=Pit/flush type.

Total FDC flow (GPM): Total flow the FDC must accommodate.
FDC connections needed: Number of separate FDC assemblies required.
Inlet connections: Number of 2.5" or 4" inlets needed.
Required FD inlet pressure (PSI): Pressure the fire department pumper must deliver at the FDC.
Elevation pressure (PSI): Static head from FDC to highest outlet.
FD pumper capacity OK: 1=Typical pumper (150 PSI) can supply, 0=May need relay pumping.
Hydrant distance OK: 1=Within 100 ft, 0=Exceeds NFPA requirement.
Check valve required: Always 1. Check valve prevents backflow from system into FDC.
Signage type: 1=AUTO SPKR, 2=STANDPIPE, 3=AUTO SPKR & STANDPIPE.
4" Storz sufficient: 1=Single 4" Storz coupling is adequate, 0=Need multiple connections.

Identify Input Parameters
4 parameters
System type served = 3, Sprinkler demand (GPM) = 250, Standpipe demand (GPM) = 500, Building height (ft) = 50 = 6 input(s) provided
Calculate Total FDC flow
Total FDC flow
500 = 500
Calculate FDC connections needed
FDC connections needed
1 = 1
Calculate Inlet connections
2 = 2
Calculate Required FD inlet pressure
Required FD inlet pressure = residualPSI + elevationPressurePSI + frictionEstimatePSI
136.7 = 136.7