🚒 Fire Fighting

Fire Pump Sizing Calculator

Size fire fighting pumps for buildings. Calculate required flow rate, total head, and pump motor rating per IS 12288 and NBC 2016 fire safety requirements.

📐 Standard: IS 12288 / NFPA 20
✅ Free to use
📄 PDF export
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ℹ️ About This Calculator

The fire pump is the heart of a building's fire fighting system. Under-sizing a fire pump leaves the system unable to deliver adequate flow at required pressure; over-sizing wastes energy and capital. This calculator sizes the main fire pump, jockey (pressure maintenance) pump, and checks motor rating per IS 12288, NBC 2016 Part 4, and NFPA 20.

IS 12288 specifies requirements for centrifugal fire pumps in India. NBC 2016 Part 4 (Fire and Life Safety) mandates pump sizing for different occupancy types and building heights. Key requirements: main fire pump (electric motor driven), standby pump (diesel engine driven), and jockey pump (pressure maintenance). Jockey pump capacity: 10% of main pump flow. Testing: performance test at 150% rated flow (pump must deliver ≥ 65% rated head). Diesel standby must start within 10 seconds.

📐 Fire Pump Sizing Formula

IS 12288 / NFPA 20

Required Flow (Q):
  Q = hose stream demand + sprinkler demand
  NBC 2016: Q_hydrant = no. of hose streams × 900 LPM (typ. 2–4 streams)
  Sprinkler: Q_spr = design area × density (L/min/m²)

Total Head (H):
  H = static head + friction losses + residual pressure at outlet
  H_static = elevation difference (m) × 0.1 bar/m
  H_friction = from Hazen-Williams or Darcy-Weisbach
  Residual: 3.5 bar at topmost hydrant (NBC)

Motor Rating:
  P_shaft = (Q × H × ρg) / (η_pump × η_motor)
  P_motor = P_shaft × 1.15 safety margin

❓ Frequently Asked Questions

What is the role of the jockey pump? +
The jockey (pressure maintenance) pump keeps the fire fighting system pressurized at all times. Minor leaks or pressure drops due to thermal expansion are compensated by the jockey pump cycling on/off. It should start before the main pump and have a capacity of 10% of the main pump. If the jockey pump cannot maintain pressure (indicating a fire event or major break), the main fire pump starts automatically.
Should the standby pump be diesel or electric? +
NBC 2016 requires a diesel-driven standby pump for buildings above 15 m (Group A residential) or any high-rise/special occupancy. The diesel pump ensures the fire fighting system operates even during a power failure (which commonly accompanies fires). The diesel engine must be capable of automatic starting and rated to run continuously for at least 6 hours on its fuel tank.
What residual pressure is required at the topmost hydrant? +
NBC 2016 specifies 3.5 bar (35 m head) residual pressure at the topmost and most hydraulically remote hydrant outlet. This ensures the fire hose delivers adequate flow. Static pressure at any hydrant must not exceed 7 bar (to protect hose coupling and control). Pressure-reducing valves are required where static pressure exceeds 7 bar.
How do I select the pump impeller size? +
Fire pumps are centrifugal pumps selected from manufacturer's curves at the design duty point (Q design, H design). The impeller should place the duty point at or slightly to the right of the BEP (Best Efficiency Point). The rated flow point (100% Q) should be on the steep part of the curve; at 150% Q, head should be ≥ 65% rated head (IS 12288 churn/runout requirements).
Do I need a fire water storage tank? +
Yes, per NBC 2016: a dedicated fire water storage tank separate from domestic water. Minimum storage: 2 hours of maximum fire demand flow. The tank must have a sluice valve isolating the fire supply – never valved off during occupation. Gravity overhead tanks are insufficient for multi-storey buildings; ground-level tanks with pressurized distribution are standard.

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⚠️ Disclaimer: For preliminary engineering design only. Verify all results with a licensed engineer before use. Full disclaimer →

🚒 Fire Pump Sizing Calculator
Reference: IS 12288 / NFPA 20