Fire Pumps (NFPA 20): Types, Performance Requirements & Selection

Quick Answer

A fire pump is a stationary pump dedicated to supplying water at the flow and pressure a fire protection system demands, governed by NFPA 20 (Standard for the Installation of Stationary Pumps for Fire Protection). Unlike general-purpose pumps, fire pumps must be listed or approved by a recognized testing laboratory (UL 448 / FM 1319) and labelled for fire pump service. Every listed fire pump must meet a three-point performance curve: churn (no-flow) pressure must not exceed 140% of rated pressure; the pump must deliver rated capacity at 100% flow; and at 150% of rated flow it must still produce at least 65% of rated pressure. The four common types are horizontal split-case (double-suction impeller, dominant for large commercial and industrial systems), vertical inline (compact, ~30% less space, cost-effective below roughly 1,000–1,250 gpm, ideal for retrofits), end suction (economical, smaller capacities), and vertical turbine (the only choice when the water source is below grade — wells, sumps, reservoirs, underground tanks — because the submerged bowl assembly needs no priming). Every system also needs a jockey pump to maintain standby pressure and prevent nuisance starts, a listed controller, and a test header for acceptance and annual flow testing. Drivers may be electric motor, diesel engine, or steam turbine; NFPA 20 limits pump brake horsepower to no more than 115% of the motor nameplate rating.

A fire pump spends almost its entire life doing nothing. It sits in a pump room, pressurised and idle, for years at a time. Then one day a sprinkler head opens, system pressure drops, the controller senses it, and the pump must start within seconds and deliver full rated flow — reliably, at the right pressure, with no opportunity for a second attempt. There is no equipment in a building where the gap between "how often it runs" and "how much depends on it running" is wider.

That is why fire pumps are regulated differently from every other pump in a facility. They cannot simply be selected from a catalogue on flow and head. They must be listed by UL or FM specifically for fire pump service, installed per NFPA 20, supplied by a continuously available power source, fitted with a listed controller, and proven by acceptance testing before the building is occupied — then flow-tested annually for the rest of their service life.

For consulting engineers, contractors, facility managers, and procurement teams specifying fire protection equipment — this guide covers fire pumps under NFPA 20: the pump types and when each applies, the performance requirements every listed pump must meet, jockey pumps and pressure settings, drivers and controllers, and the installation and testing requirements that determine whether a system passes acceptance.

For general pump background, see Centrifugal Pumps and Industrial Pumps Guide.

What a Fire Pump Does

A fire pump augments available water supply pressure when the source alone cannot meet the hydraulic demand of sprinkler systems, standpipes, or hose streams.

The sequence:

1. A sprinkler head opens or a hose valve is used
2. Water flows, and system pressure drops
3. The pressure drop is sensed by the fire pump controller
4. The controller automatically starts the pump
5. The pump restores and maintains the required pressure and flow
6. The pump runs until manually shut down (most listed controllers require manual stop)

NFPA 20 Performance Requirements

Every listed fire pump must satisfy a three-point performance curve. This is the defining technical requirement of fire pump selection:

Why churn matters: at no flow, the pump still develops pressure ("churn" or shut-off pressure). If churn pressure plus maximum static suction pressure exceeds the system's pressure rating, components can be over-pressured — which is why churn must be included in the system pressure calculation and why a relief valve may be required.

Why 150% matters: it guarantees the pump can deliver substantially more than rated flow during a large fire without pressure collapsing.

Listing and Approval

Only pumps, drivers, and controllers listed or approved by a recognized laboratory (UL, FM Approvals) may be installed. Fire pumps must be specifically labelled for Fire Pump Service. Performance criteria are established by UL 448, FM 1319, and ANSI/HI 14.6.

Factory Testing

Each pump must be supplied with a certified shop test curve demonstrating performance at churn, 100%, and 150% of rated flow.

Motor Sizing

NFPA 20 requires the driver to be rated for the peak brake horsepower the pump can draw. The pump's maximum brake horsepower must not exceed the motor nameplate rating by more than 15% (service factor).

Fire Pump Types

Horizontal Split-Case

The casing splits horizontally along the shaft centreline; the impeller is double-suction, which balances axial thrust. Bearings support the shaft on both sides.

• Dominant choice for large commercial and industrial systems
• Handles high flow with easy maintenance access (top casing lifts off without disturbing piping)
• Requires a flooded suction — the water source must be at or above pump level
• Must be mounted on a concrete housekeeping pad
• Larger footprint and higher cost in smaller sizes

Vertical Inline

Close-coupled with the motor mounted vertically above horizontally aligned suction and discharge connections.

• Needs up to 30% less space than an equivalent end-suction pump
• Can mount on pipe stand supports rather than a concrete base — ideal for retrofits and replacements
• Generally more cost-effective below roughly 1,000–1,250 gpm
• Self-venting, no pump bearings, single stuffing box (reduced leakage)
• Light to medium-large capacity, topping out around 1,000 gpm at 184 psi
• Larger sizes need lifting gear to remove the motor for impeller access

End Suction

Single-suction impeller with axial inlet and radial discharge.

• Economical for smaller capacities
• Simple, compact
• Requires flooded suction

Vertical Turbine

A vertical shaft with multiple submerged impeller stages; the motor sits above the discharge head at grade.

• The only option when the water source is below grade — wells, sumps, open reservoirs, lakes, underground tanks
• The submerged bowl assembly eliminates priming requirements
• Flow and head capacities similar to horizontal split-case
• Requires deeper installation planning and shaft maintenance expertise
• Needs adequate submergence — insufficient depth causes air entrainment and loss of prime

Positive Displacement

NFPA 20 also covers PD pumps for foam concentrate, water mist, and additive injection duties, where accurate proportioning matters more than bulk flow. For the full family, see Positive Displacement Pumps.

Type Selection Summary

Jockey Pumps and Pressure Settings

What a Jockey Pump Does

A jockey (pressure maintenance) pump is a small pump that keeps the system pressurised against minor leaks and thermal expansion, so the main fire pump does not start every time pressure dips slightly.

A failed or wrongly set jockey pump causes the main fire pump to short-cycle — accelerating wear on equipment designed for occasional operation, and in the worst case masking a real demand.

Setting the Pressure Band

The jockey pump must maintain pressure above the main pump start point but below churn pressure, with enough margin to prevent nuisance starts.

A worked example for a 1,000 gpm / 100 psi pump with 115 psi churn, on a city supply of 50 psi minimum and 60 psi maximum static:

For multiple fire pumps, stagger start points in 10 psi increments so pumps sequence rather than start simultaneously.

The maximum churn figure (175 psi here) is the number that must be checked against system component ratings.

Drivers, Controllers and Power

Drivers

• Electric motor — most common; requires reliable power
• Diesel engine — required where a reliable continuous power source is unavailable; brings fuel tank, battery, cooling and exhaust requirements
• Steam turbine — rare, industrial facilities with steam supply

Power Supply

NFPA 20 requires fire pumps to be supplied by a continuously available power source. In many installations this necessitates a backup generator as a secondary source, with the controller arranged for automatic transfer.

Controllers

Fire pump controllers are listed devices meeting NFPA 20 requirements for starting, stopping, and fault indication. They also provide motor protection, phase monitoring, and run indication. Most are arranged for automatic start on pressure drop and manual stop.

Installation Requirements

Pump room: must be readily accessible, properly ventilated, and constructed of fire-resistive materials. Protected against freezing and flooding.

Suction piping: sized to avoid cavitation and vortexing; NFPA 20 restricts eccentric reducers, elbow placement near suction, and requires specific straight-run distances. Excessive suction lift on a horizontal pump is a classic cause of cavitation and premature failure.

Discharge piping: includes a check valve and control valve; sized for 150% flow.

Relief valve: may be required where churn plus maximum suction pressure exceeds component ratings, and is required on diesel-driven units in some configurations.

Test header: allows full-flow testing without discharging into the sprinkler system. NFPA 20 requires full-flow acceptance and annual testing — a system installed without adequate test header capacity or drain piping cannot be commissioned.

Gauges, valves and fittings: suction and discharge gauges, casing relief, air release, and sensing line arrangements are all specified.

For the valves in fire pump packages, see Check Valves and Globe Valve vs Gate Valve.

Testing

Acceptance test: full flow test at churn, 100%, and 150% of rated capacity, verified against the certified shop curve, with controller and driver function testing.

Annual flow test: repeats the three-point test to confirm the pump still meets its curve. Degradation below the NFPA thresholds requires investigation and repair.

Weekly / monthly churn test: short no-flow run to confirm the pump starts and runs (frequency depends on driver type and edition adopted).

Common Specification Mistakes

After 15+ years supplying pumps and industrial equipment to projects:

Mistake 1: Selecting by Catalogue Instead of Suction Source

Choosing a pump type from familiarity rather than matching it to the water source. A horizontal split-case pump installed with excessive suction lift cavitates, overheats, and fails prematurely.

Prevention: Let the water source drive the type. Below-grade source → vertical turbine. Flooded suction → horizontal split-case or inline.

Mistake 2: Inadequate Vertical Turbine Submergence

Vertical turbine installed in a shallow tank without sufficient submergence. It draws air, loses prime, and cannot deliver rated flow.

Prevention: Verify minimum submergence per the manufacturer and NFPA 20, including at the lowest usable water level.

Mistake 3: Ignoring the Jockey Pump Pressure Band

Jockey settings not coordinated with the fire pump. The main pump short-cycles, or fails to start when actually needed.

Prevention: Calculate the full pressure band (jockey stop/start, pump start/stop, max churn) using minimum and maximum static supply pressures.

Mistake 4: Forgetting Churn Pressure in System Design

System components rated for the pump's rated pressure only. At churn with maximum suction pressure, the system is over-pressured.

Prevention: Design to churn pressure + maximum static suction pressure. Add a relief valve where this exceeds component ratings.

Mistake 5: No Test Header or Drain Capacity

Pump installed without adequate test header or drainage. Acceptance testing cannot be performed and the system cannot be commissioned.

Prevention: Design the test header and drain path at the outset, sized for 150% of rated flow.

Mistake 6: Unlisted Components

A non-listed pump, controller, or driver specified to save cost. The installation fails inspection and must be replaced.

Prevention: Every pump, driver, and controller must be UL listed or FM approved and labelled for fire pump service. There is no substitution.

Supply from Kasko Makine

Kasko Makine supplies fire pumps, fire protection equipment, and associated piping materials for commercial, industrial, and infrastructure projects:

Fire pump packages:

• Horizontal split-case fire pumps
• Vertical inline fire pumps
• End suction fire pumps
• Vertical turbine fire pumps
• Jockey / pressure maintenance pumps
• Complete skid-mounted packages

Drivers and controls: electric motor and diesel engine drivers, listed fire pump controllers, automatic transfer arrangements

System components: suction and discharge piping, check valves, control valves, relief valves, gauges, test headers, hose valve manifolds, fittings and flanges

Compliance: UL listed / FM approved equipment, NFPA 20 compliant packages, certified shop test curves, documentation for acceptance testing

Engineering support:

• Pump type selection based on water source
• Flow and pressure sizing against system demand
• Churn and pressure band calculation
• Jockey pump coordination
• Pump room and piping layout review
• Documentation for authority having jurisdiction (AHJ) approval

Logistics: Fire pump packages shipped from Istanbul to projects across Africa, the Middle East, Central Asia, and beyond. Standard packages 8-14 weeks; diesel and vertical turbine packages 14-22 weeks.

Need fire pumps or fire protection equipment? Send us your required flow (gpm or m³/h) and pressure, water source type and elevation, driver preference (electric or diesel), applicable code edition, and project location to info@kaskomakine.com or WhatsApp +90 (537) 521 1399. We'll recommend a compliant pump type, verify the performance curve and pressure band, and provide a quotation with certification within 48 hours.

Continue Reading: Pump & Valve Guides

• Industrial Pumps Guide — All pump types and how to choose
• Centrifugal Pumps — Working principle, NPSH, and BEP
• Check Valves — Discharge check valves
• Globe Valve vs Gate Valve — Control and isolation valves

Frequently Asked Questions

Q: What is NFPA 20?
A: NFPA 20 is the Standard for the Installation of Stationary Pumps for Fire Protection. It governs fire pump types, drivers, controllers, suction and discharge piping, pump room construction, pressure settings, installation, and testing requirements. Under NFPA 20, only pumps, drivers, and controllers listed or approved by a recognized testing laboratory (UL, FM Approvals) may be installed, and pumps must be specifically labelled for Fire Pump Service. The standard establishes the three-point performance curve every listed fire pump must meet, requires a continuously available power source, mandates acceptance and annual flow testing, and specifies the pump room, piping, and accessory requirements that determine whether an installation passes inspection.

Q: What are the NFPA 20 fire pump performance requirements?
A: Every listed fire pump must satisfy a three-point performance curve. At churn (zero flow), total head must not exceed 140% of rated total head. At 100% flow, the pump must deliver its rated capacity at rated pressure. At 150% of rated flow, the pump must still produce at least 65% of rated total head. Each pump must be supplied with a certified factory shop test curve demonstrating these three points. Additionally, the pump's maximum brake horsepower must not exceed the driver's nameplate rating by more than 15%. These same three points are verified during acceptance testing and repeated in the annual flow test throughout the pump's service life.

Q: What are the main types of fire pumps?
A: Four centrifugal types are common. Horizontal split-case pumps have a casing split along the shaft centreline and a double-suction impeller balancing axial thrust — they dominate large commercial and industrial systems, offer easy maintenance access, but require flooded suction and a concrete pad. Vertical inline pumps are close-coupled with the motor above the piping, need up to 30% less space, can mount on pipe stands, and are usually more cost-effective below about 1,000–1,250 gpm — ideal for retrofits. End suction pumps are economical for smaller capacities. Vertical turbine pumps have submerged multi-stage bowl assemblies and are the only option when the water source is below grade (wells, sumps, reservoirs), since they require no priming. Positive displacement pumps serve foam and additive proportioning.

Q: What is a jockey pump and why is it needed?
A: A jockey pump (also called a pressure maintenance pump) is a small pump that keeps the fire protection system pressurised against minor leaks and thermal expansion. Without it, every small pressure drop would start the main fire pump — causing excessive cycling and accelerating wear on equipment designed for occasional operation. The jockey pump must be set to maintain pressure above the main fire pump's start point but below churn pressure, with enough margin to prevent nuisance starts. Typical practice sets jockey stop at churn pressure plus minimum static supply pressure, jockey start 10 psi below that, and fire pump start 5 psi below jockey start. A failed or mis-set jockey pump is a common cause of fire pump short-cycling.

Q: What is churn pressure on a fire pump?
A: Churn pressure (also called shut-off or no-flow pressure) is the pressure a fire pump develops when running with zero flow. Under NFPA 20, churn pressure must not exceed 140% of the pump's rated total head. Churn matters for system design because the total pressure the system sees is churn pressure plus the maximum static suction supply pressure — for example, a pump with 115 psi churn on a supply with 60 psi maximum static produces 175 psi maximum system pressure. If this figure exceeds the pressure rating of system components, a relief valve is required. Churn pressure is also one of the three points verified in factory, acceptance, and annual testing.

Q: When do you need a vertical turbine fire pump?
A: A vertical turbine fire pump is required whenever the water source is below the pump elevation — wells, sumps, open reservoirs, lakes, or underground storage tanks. Horizontal split-case, inline, and end-suction pumps all require a flooded suction, meaning the water source must be at or above pump level; installing one with excessive suction lift causes cavitation, overheating, and premature failure. A vertical turbine's multi-stage bowl assembly is submerged in the water source with the motor mounted above the discharge head at grade, eliminating priming requirements entirely. The trade-offs are deeper installation planning, shaft maintenance expertise, and the need to verify adequate submergence at the lowest usable water level.