Free tool · FPS
Fire Water Storage Tank Sizing
Dedicated fire-water reserve from sprinkler, hydrant and hose demands with explicit duration, reserve and usable-volume checks.
Free · no sign-in requiredInputs
L/min
Enter the hydraulically calculated or code-prescribed demand
min
L/min
min
L/min
Use only when not already included in another demand
min
Use the combination required by the adopted code and AHJ
%
Suction clearance, low-level cut-off and dead storage
%
nos
Results
Gross fire-water storage
448.8 m³
224.4 m³ per compartment · 4180 L/min governing flow
Demand volumes
- Sprinkler reserve
- 114.0 m³
- Hydrant / standpipe reserve
- 273.6 m³
- Additional hose reserve
- 0.0 m³
- Net usable reserve
- 387.6 m³
Tank selection
- Combination basis
- Simultaneous sum
- Gross capacity
- 448.8 m³
- Compartments
- 2 nos
- Capacity per compartment
- 224.4 m³
Engineering checks
Positive duration provided for every active demand
Unusable allowance included — Confirm suction low-level, freeboard and dead storage with the tank arrangement
At least two compartments for maintainability — Verify compartmentation and usable reserve requirements with the AHJ
Demand combination explicitly selected
Formulae used
- Individual reserve = design flow × required duration ÷ 1000
- Net usable reserve = sum of simultaneous demand volumes, or largest non-simultaneous volume
- Gross tank volume = net reserve × (1 + design reserve) ÷ usable fraction
- Capacity per compartment = gross volume ÷ compartment count
Assumptions & limits
- The designer supplies code/AHJ-approved flow, duration and simultaneity; the calculator does not infer hazard classification.
- Domestic/process storage is excluded unless the approving authority expressly permits a combined tank with a protected fire reserve.
- The gross result includes the entered unusable allowance but not structural freeboard unless included by the user.
- Confirm refill provisions, suction geometry, vortex protection, access and sectional operation during detailed design.
Standards: NBC 2016 Part 4 (fire-water supply by occupancy/building type) · IS 15105:2021 (sprinkler demand and water supply) · IS 3844 (internal hydrants) · IS 13039 (external hydrants) · NFPA 13 (sprinkler demand/duration) · NFPA 14 (standpipe demand) · NFPA 22 (water tanks); verify the edition adopted by the project/AHJ
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