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Fire water tank + pumps: volume, head, power
Enter the flow and duration of each system (from the Sprinkler, Hydrant and Outdoor tools) and the building height. The tool returns the minimum tank volume and main and jockey pump data.
Quick answer
Minimum fire water tank 144.0 m³. Main pump 144 m³/h at 45 m (4.4 bar), 37.0 kW motor; jockey pump about 1.4 m³/h at 52 m.
Preliminary results
Min. tank144.0m³
Pump flow144m³/h
Head45m
Motor37.0kW
| Step | Result | Basis |
|---|---|---|
| Sprinkler water3,6 × 30.0 × 60/60 | 108.0 m³ | TCVN 7336:2021 ⚠ |
| Indoor hydrant water3,6 × 10.0 × 60/60 | 36.0 m³ | TCVN 3890:2023 ⚠ |
| Tank volumeΣW | 144.0 m³ | — |
| Main pump flow30.0 + 10.0 L/s | 144 m³/h | — |
| Head H = Z + P·10.2 + ΔH20 + 1.0 × 10,2 + 15 | 45.2 m | — |
| Shaft power9,81 × 0.040 × 45.2 / 0.65 | 27.3 kW | — |
| Motor (15 % margin)≥ 1,15 × 27.3 | 37.0 kW | — |
| Jockey pump~1 % Q; H + 7 m | 1.4 m³/h · 52 m | NFPA 20 ⚠ |
- Main and standby pumps have the same duty; standby is diesel or on a second power source.
- The jockey pump keeps system pressure and starts the main pump when pressure drops.
- Each pump has its own suction; the fire reserve is not used for domestic water.
Sources and assumptions. W = Σ 3.6·Q·t (Q L/s, t h); sprinkler duration per TCVN 7336:2021, hydrants 1 h, outdoor 3 h ⚠. H = Z + P·10.2 + ΔH; P_shaft = ρ·g·Q·H/η, motor ≥ 1.15·P_shaft. Jockey ~1 % of main flow, about 0.7 bar higher head (NFPA 20) ⚠. Final pump selection follows the maker's curve. ⚠ = code table value to be checked against the original standard. Preliminary results for material selection and budgeting; not a substitute for an approved fire protection design.
Suggested materials
Main fire pump (electric) 144 m³/h – 45 m, 37.0 kW1
Standby fire pump (diesel or electric) 144 m³/h – 45 m1
Jockey pump 1.4 m³/h – 52 m1
Fire pump controller1
Frequently asked questions
How big should a factory fire water tank be?
Sum of simultaneous flows × duration: e.g. sprinklers 30 L/s × 1 h = 108 m³ plus hydrants 10 L/s × 1 h = 36 m³ gives 144 m³, before outdoor water if taken from the tank.
Why a jockey pump?
Fire mains always leak slightly; the jockey keeps pressure so the main pump does not cycle, and when a sprinkler opens the pressure drop starts the main pump.