Fire Pump Design and Installation
What You Need to Know
Fire pumps drive every hydrant and sprinkler system in a commercial building. Without the right pump, your hydrants deliver a trickle when the brigade needs a flood. AS 2941:2013 sets the rules for fire pumpset design, manufacture, installation, and commissioning in Australia. AS 2419.1:2021 tells you the flow and pressure your hydrant system must hit. Get the duty point wrong, and you fail the commissioning test. Get the pump room wrong, and you fail the building certifier.
The Rules
- Fire pumpsets must comply with AS 2941:2013 for design, installation, and commissioning - referenced by the NCC as a deemed-to-satisfy solution (NCC 2025)
- Hydrant system flow and pressure requirements come from AS 2419.1:2021 — full-duty pumps deliver 10 L/s per hydrant outlet; half-duty pumps deliver 5 L/s per outlet (AS 2419.1, Clause 2.2.6)
- Buildings over 50 m effective height require full-duty pumps at 10 L/s per outlet (AS 2419.1:2021)
- Buildings over 25 m effective height require two pumps for redundancy (AS 2419.1:2021, Clause 2.2.8)
- The pump must deliver the required flow at the most hydraulically disadvantaged outlet after accounting for friction losses, elevation head, and fittings (AS 2419.1:2021)
- Diesel pumpsets must run for a minimum of 90 minutes during shop testing at 130% duty flow; electric pumpsets must run for 15 minutes (AS 2941:2013)
- Diesel fuel tanks must hold enough fuel for at least 6 hours of continuous operation at full load (AS 2941:2013)
- Fire pump controllers must start the pump automatically on pressure drop and provide alarm signals, event recording, and manual override (AS 2941:2013)
- Diesel pumps must sit in a separate room from the fire control centre (NCC 2025, Specification E1.8)
- Each pumpset must have a certificate of conformance with a unique serial number before it leaves the factory (AS 2941:2013)
What This Means in Practice
Take a 6-storey commercial office building at 24 m high with hydrants and sprinklers fed from a combined water tank. The hydraulic calculation calls for two hydrant outlets flowing at the same time. Under AS 2419.1, each outlet needs 10 L/s. Add the sprinkler demand of around 5 L/s for a Light Hazard office area. The total system demand is about 25 L/s.
The pump must push that 25 L/s through 100 mm and 150 mm mains, up 24 m of elevation, through gate valves, check valves, and tee fittings. After you add friction losses, the pump duty point lands around 25 L/s at 500 to 700 kPa. That drives you towards a centrifugal end-suction or split-case pump with a 15 to 22 kW electric motor or equivalent diesel engine.
The fire water tank for this building holds around 50,000 to 60,000 L. The tank feeds the main fire pump, a backup pump (diesel or electric, opposite driver type to the main pump), and a small jockey pump. The jockey pump runs at about 1 to 2 L/s and keeps the system pressurised at around 50 kPa above the main pump start pressure. This stops the main pump cycling every time a gauge fitting weeps or a valve seat leaks slightly.
When a hydrant valve opens, the system pressure drops. The controller detects this drop and starts the main pump within 10 to 15 seconds. If the main pump fails to start, the backup pump kicks in. The fire brigade connects to the booster assembly at street level and can pump extra water into the system to supplement the on-site supply.
Key Design Decisions
Electric vs. Diesel Driver
Electric pumps cost less to install, run quieter, and need less maintenance. Diesel pumps run independently of the building’s power supply. AS 2941 allows either driver type, but most engineers specify one of each for redundancy. A 22 kW electric pump paired with an equivalent diesel pump covers both normal operation and power failure.
Pump Duty Point Selection
The duty point comes from the hydraulic calculation, not from a catalogue. You need the total system flow (sprinklers plus hydrants flowing simultaneously) at the residual pressure required at the most remote outlet. Oversizing the pump wastes energy and can cause pressure spikes that damage fittings. Undersizing means the furthest hydrant runs dry.
Pump Room Location and Size
The pump room needs direct access for the fire brigade, a concrete floor with drainage to a sump, and enough clearance for pump removal. Allow 20 to 30 m² for a dual pump set with controllers, a jockey pump, and manifold pipework. Diesel pump rooms need separate ventilation and exhaust ducting to direct fumes away from occupied areas and fire brigade access paths.
Water Supply Arrangement
Most commercial buildings use a ground-level or basement tank fed by the town main through a backflow prevention device. The tank must hold the full fire reserve - typically 30 to 60 minutes of combined sprinkler and hydrant demand. A 25 L/s system running for 30 minutes needs 45,000 L of storage. The pump draws from the tank through a dedicated suction line with a foot valve and strainer.
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References
- AS 2941:2013, Fixed fire protection installations — Pumpset systems
- AS 2419.1:2021, Fire hydrant installations — System design, installation and commissioning
- AS 1851:2012, Routine service of fire protection systems and equipment
- National Construction Code 2022, Volume One, Specification E1.8 — Fire control centres
- National Construction Code 2022, Volume One, Part E1 — Fire-fighting equipment