Whe
n engineers compare electric vs. diesel fire pumps, the discussion usually centers on the driver: Is the building better protected with a reliable electric motor, or does the application justify a diesel engine that can operate independently of normal utility power?
But there is another pump in the room that plays a completely different role.
The jockey fire pump does not compete with the electric or diesel fire pump. It supports the entire fire protection system by maintaining pressure during normal conditions and handling small pressure losses before they become a reason for the main fire pump to start.
This distinction is becoming increasingly important as fire protection systems become more connected, closely monitored, and engineered around reliability rather than simply equipment selection. The 2025 edition of NFPA 20 continues to recognize the jockey pump as the standard term for pressure-maintenance and make-up pumps, while also refining requirements around automated testing, remote testing, controllers, power arrangements, and monitoring.
So, where exactly does the jockey pump fit when choosing between electric and diesel fire pumps?
The short answer is: it belongs upstream in the pressure-maintenance strategy, not in the electric-vs-diesel decision itself.
Electric and Diesel Fire Pumps Have Different Jobs
A fire pump is selected to provide the water flow and pressure required by the fire protection system when there is an actual demand.
That demand may come from:
- Automatic sprinkler activation
- Standpipe or hose valve operation
- Hydrant demand
- Deluge or water spray systems
- Other engineered fire protection applications
The driver determines how the main fire pump receives the energy required to deliver that water.
Electric fire pumps
An electric fire pump uses an electric motor as its driver. Its biggest advantage is straightforward operation when a reliable power supply is available.
Electric systems generally have:
- No diesel fuel storage
- No engine oil or fuel filters
- Fewer engine-related maintenance requirements
- Compact equipment arrangements
- No combustion exhaust system
- Straightforward starting and monitoring
However, the reliability of the electrical supply becomes a critical design consideration.
An electric fire pump is only as dependable as the power arrangement supporting it. NFPA 20 contains specific requirements addressing electric fire pump power supplies and controllers, and the authority having jurisdiction (AHJ) ultimately plays an important role in determining whether the available power arrangement is acceptable.
Diesel fire pumps
A diesel fire pump uses an engine rather than an electric motor.
That makes it particularly useful where maintaining fire pump operation independently of normal utility power is an important part of the system's reliability strategy.
Diesel installations introduce additional considerations, including:
- Fuel storage
- Batteries and battery charging
- Engine cooling
- Ventilation
- Exhaust
- Fuel maintenance
- Engine testing
- Additional mechanical components
The 2025 edition of NFPA 20 includes specific provisions addressing diesel engine-driven pumps, controllers, automatic testing, monitoring, and fuel-related arrangements.
Neither driver is universally "better."
The right selection depends on the building, available power, fire protection demand, environmental conditions, applicable codes, AHJ requirements, and the overall reliability strategy.
And this is where the jockey pump enters the picture.
What Is a Jockey Pump?
A jockey pump is a small pressure-maintenance pump designed to keep the fire protection system pressurized during normal conditions.
Think of the main fire pump as the equipment designed for a significant event.
The jockey pump handles the much smaller events that happen routinely.
Fire protection piping does not remain perfectly static forever. Small pressure losses can occur because of:
- Minor leakage
- Temperature-related pressure changes
- Small valve-seat leakage
- Maintenance activities
- Pressure fluctuations
- Other normal system conditions
Without a pressure-maintenance strategy, these relatively small losses could cause the main fire pump to start.
That is not what the main fire pump is intended to do.
The jockey pump compensates for these minor losses and restores system pressure without unnecessarily operating the primary fire pump.
NFPA 20's 2025 edition specifies that a pressure-actuated fire pump system is to have a means of maintaining pressure, with a jockey pump being one recognized method. It also establishes requirements for jockey pump discharge pressure, piping, controls, and related components.
The Jockey Pump Is Not a Backup Fire Pump
This is one of the most important distinctions engineers, facility managers, and building owners need to understand.
A jockey pump is not a smaller version of the main fire pump.
It is not intended to replace the electric fire pump.
It is not intended to replace the diesel fire pump.
And it should not be treated as an emergency fire pump.
Its primary function is pressure maintenance.
The main fire pump is selected around the hydraulic demand of the fire protection system. The jockey pump, by contrast, is selected around maintaining system pressure and preventing unnecessary operation of the main fire pump.
NFPA 20 specifically states that the primary or standby fire pump should not be used as a jockey pump, except under specific provisions in the standard.
That separation of duties is fundamental to proper system design.
How the Three Pumps Work Together
Consider a typical fire protection system containing:
- An electric-driven fire pump
- A diesel-driven fire pump
- A jockey pump
The three pumps are not simply three different sizes of the same equipment.
They represent three different functions.
1. Jockey pump: Maintain pressure
During normal conditions, the jockey pump keeps the system pressure within the desired range.
A small pressure drop occurs.
The jockey pump starts.
It restores pressure.
Once the pressure reaches its designated stop point, the jockey pump stops.
2. Electric fire pump: Respond to significant demand
If system pressure continues to fall beyond the jockey pump's ability to compensate, the electric fire pump may start according to the system's pressure settings and control logic.
This is associated with a substantially greater water demand.
3. Diesel fire pump: Provide another driver option
If the system is designed with both electric and diesel-driven fire pumps, the diesel unit provides an additional source of pumping capability based on the system's design and sequencing.
The exact arrangement depends on the project and applicable requirements.
The key idea is simple:
The jockey pump manages pressure. The main fire pumps manage fire demand.
Why Does the Jockey Pump Matter With an Electric Fire Pump?
At first glance, the jockey pump might seem less important when the main fire pump is electric.
After all, electric motors can start quickly and are relatively straightforward to operate.
But frequent unnecessary starts are still undesirable.
Every time the main fire pump starts, the system is asking a much larger piece of equipment to respond to what may be a very small pressure loss.
The jockey pump provides a controlled first response.
This helps separate normal pressure maintenance from genuine system demand.
For example, imagine a sprinkler system experiencing a small pressure reduction because of minor leakage.
Without a suitable pressure-maintenance arrangement, the pressure may eventually reach the main pump's start setting.
The electric fire pump starts.
Water moves.
The pump runs according to its control strategy.
Then the system pressure recovers.
This is a disproportionate response to a minor condition.
A correctly designed jockey pump can handle that smaller pressure loss instead.
What About Diesel Fire Pumps?
The same principle applies when the main fire pump is diesel-driven.
The jockey pump does not become unnecessary simply because the primary driver is an engine.
In fact, separating pressure maintenance from emergency pumping becomes particularly useful because diesel equipment has additional mechanical systems that operators must maintain.
A diesel fire pump involves more components than an electric motor-driven pump, including batteries, engine systems, fuel systems, cooling arrangements, and exhaust provisions.
There is little reason to start that equipment for every minor pressure fluctuation if a properly selected pressure-maintenance pump can handle the condition.
This is also consistent with the broader direction of modern fire pump design: reduce unnecessary equipment operation while making testing, monitoring, and system performance more verifiable.
NFPA 20's 2025 edition has expanded and refined provisions for automatic and remote automatic testing for both electric- and diesel-driven fire pumps, along with monitoring requirements.
Does the Jockey Pump Need to Be Electric or Diesel?
This is where the terminology can become confusing.
A jockey pump is normally a small electrically driven pump, but the important design question is not whether it is "electric vs. diesel" in the same sense as the main fire pump.
The jockey pump has a different duty.
NFPA 20's 2025 requirements state that a jockey pump is not required to have alternate or standby power.
That is an important distinction.
The main fire pump's driver is selected around the ability to provide the required fire protection water supply under emergency conditions.
The jockey pump's job is pressure maintenance under normal system conditions.
Therefore, engineers should avoid applying the same selection logic to both.
Pressure Settings Are Where the Jockey Pump Really Fits
The relationship between the jockey pump and the main fire pump is heavily influenced by pressure settings.
The system needs a deliberate sequence.
A simplified arrangement looks like this:
Normal system pressure
↓
Small pressure loss
↓
Jockey pump starts
↓
Pressure restored
↓
Jockey pump stops
↓
Larger pressure loss
↓
Main fire pump starts
The exact pressure settings must be established based on the system design, equipment characteristics, available pressure, and applicable requirements.
NFPA technical material describes the jockey pump stop point in relation to the fire pump's churn pressure and minimum static supply pressure, with staged pressure settings separating jockey pump and fire pump activation.
This sequencing matters because poorly coordinated pressure settings can create operational problems.
If the jockey pump start and stop points are too close, it may cycle excessively.
If the jockey pump is set too aggressively, it may mask a developing problem.
If the main fire pump starts too easily, minor pressure losses can cause unnecessary activation.
If settings are poorly coordinated, the system may not behave as the design team intended.
Oversizing the Jockey Pump Can Be a Problem
A common misconception is that a larger jockey pump provides better protection.
It does not necessarily.
The jockey pump needs enough capacity to maintain pressure under expected minor losses, but making it unnecessarily large can interfere with the intended separation between pressure maintenance and fire demand.
An oversized jockey pump may restore pressure too aggressively or make it capable of handling flows that should instead trigger the main fire pump.
The result can be a system that appears stable during normal operation but behaves differently during an actual demand condition.
Jockey pump selection should therefore be based on the system's pressure-maintenance requirements rather than simply selecting the largest convenient pump.
The Jockey Pump and Modern Fire Pump Monitoring
Fire pump design is moving beyond basic mechanical equipment selection.
Modern systems increasingly incorporate:
- Remote monitoring
- Automated testing
- Controller event logs
- Digital alarms
- Equipment status monitoring
- Connectivity
- Condition-based maintenance strategies
The 2025 edition of NFPA 20 includes expanded and refined requirements for automatic and remote automatic testing, particularly for electric- and diesel-driven fire pumps. It also includes an annex addressing fire pump room connectivity.
That makes the jockey pump more than just a small pump sitting beside the main equipment.
Its starts and stops can provide useful operational information.
If a jockey pump that normally operates infrequently begins starting repeatedly, that may indicate:
- Leakage
- A pressure-control problem
- A faulty check valve
- A valve issue
- Pressure fluctuations
- A developing system condition
In other words, jockey pump cycling can become an operational signal.
Modern fire protection teams should pay attention to those patterns instead of treating every jockey pump start as routine.
A New Development: Can Technology Replace the Jockey Pump?
This is one of the more interesting developments in current fire pump engineering.
A 2025 NFPA public input proposed recognizing a listed electric fire pump controller with integrated pressure-maintenance capabilities as an alternative to a conventional jockey pump arrangement.
The proposed technology was designed to distinguish minor pressure losses from actual system demand and temporarily operate the main pump in a controlled "system recharge" mode for small losses.
This is important because it shows where the industry is heading.
The question is no longer simply:
"Which pump should we buy?"
It is increasingly:
"How should the entire fire pump system detect, manage, test, and respond to pressure changes?"
However, engineers should distinguish between a proposal or emerging technology and an adopted code requirement. A project still needs to comply with the edition of NFPA 20 adopted by the AHJ and any applicable local requirements.
Electric vs. Diesel: A Practical Comparison
| Factor | Electric Fire Pump | Diesel Fire Pump |
|---|---|---|
| Driver | Electric motor | Diesel engine |
| Main dependency | Reliable electrical supply | Fuel and engine systems |
| Fuel storage | Not required | Required |
| Exhaust system | Not required | Required |
| Engine maintenance | Lower | Higher |
| Battery maintenance | Not applicable to driver | Required |
| Typical space requirements | More compact | More equipment/ventilation needs |
| Pressure maintenance | Jockey pump can be used | Jockey pump can be used |
| Emergency role | Main fire protection pumping | Main fire protection pumping |
| Jockey pump role | Pressure maintenance | Pressure maintenance |
The key takeaway is that the jockey pump's fundamental role does not change simply because the main fire pump driver changes.
When Is an Electric Fire Pump a Strong Choice?
An electric-driven fire pump can be attractive when the project has a dependable power arrangement and the applicable requirements permit its use.
Potential advantages include:
- Lower mechanical complexity
- Easier routine maintenance
- No diesel fuel management
- Smaller equipment footprint
- No combustion exhaust
- Straightforward integration with building electrical infrastructure
But engineers should never select an electric driver solely because it is cheaper or easier to maintain.
The power supply must be evaluated as part of the complete fire protection design.
A reliable-looking electrical source is not automatically a compliant fire pump power source.
When Does Diesel Make More Sense?
Diesel becomes attractive when electrical reliability is a major concern or when the project's risk profile and code requirements favor an independent driver.
The diesel engine brings its own energy source and avoids direct dependence on normal utility power.
But that independence comes with responsibilities.
Fuel must remain usable.
Batteries must remain capable of starting the engine.
Ventilation and exhaust arrangements must work.
Cooling systems must be maintained.
Testing must be performed correctly.
The engine cannot simply be installed and forgotten.
In modern fire protection design, driver independence is valuable only when the complete diesel system is maintained as a reliable system.
Common Jockey Pump Mistakes Engineers Should Watch For
1. Treating the jockey pump as a backup fire pump
It is not.
Its purpose is pressure maintenance, not primary fire suppression.
2. Oversizing the jockey pump
A jockey pump that is unnecessarily large can interfere with the intended operating sequence.
3. Poor pressure coordination
Start and stop points need to be deliberately coordinated with the main fire pump.
4. Ignoring repeated cycling
Frequent jockey pump starts can indicate leakage or another system problem.
5. Assuming electric means automatically reliable
The electric pump's reliability depends heavily on its power supply arrangement.
6. Assuming diesel means maintenance-free independence
Diesel eliminates dependence on normal utility power, but introduces fuel, battery, cooling, exhaust, and engine maintenance requirements.
7. Treating technology as a substitute for code compliance
New controller and pressure-maintenance technologies are evolving quickly, but the installed system still has to satisfy the requirements adopted for the project.
What Engineers Should Evaluate During Pump Selection
Before selecting an electric or diesel fire pump arrangement, the engineering team should evaluate the entire system rather than focusing on the pump nameplate.
Key questions include:
What is the hydraulic demand?
The pump must be capable of meeting the required flow and pressure across the relevant operating range.
How reliable is the electrical supply?
For an electric-driven pump, the power arrangement is a fundamental part of the reliability assessment.
What happens if utility power is unavailable?
If continued pumping capability is required independent of normal utility power, a diesel arrangement or another compliant power strategy may need to be considered.
What pressure must the jockey pump maintain?
The jockey pump should be selected to perform its pressure-maintenance duty without taking over the role of the main fire pump.
How will the pumps be sequenced?
Pressure switches, controllers, pressure-sensing lines, and pump settings need to work together.
How will the system be monitored?
Modern projects should consider how pump status, alarms, testing, and unusual operating patterns will be identified.
What does the AHJ require?
Code compliance cannot be separated from local adoption, project-specific requirements, and AHJ interpretation.
The Bigger Picture: Think in Terms of a Pumping Strategy
The electric-versus-diesel debate can become too narrow when it focuses only on the driver.
A properly engineered fire pump system is a coordinated network.
The water supply provides the available source.
The main fire pump delivers the required fire flow.
The driver provides the energy.
The controller manages starting and operation.
The jockey pump maintains pressure during normal conditions.
The monitoring system provides visibility into equipment status and abnormal behavior.
Each component has a specific job.
The goal is not simply to select the strongest pump.
It is to make sure the right pump responds to the right condition.
Final Takeaway
So, where does the jockey pump fit in the electric vs. diesel fire pump discussion?
It fits beside the main fire pump as a pressure-maintenance component, not as an alternative driver.
Whether the primary fire pump uses an electric motor or diesel engine, the jockey pump can help maintain system pressure and prevent minor pressure losses from unnecessarily starting the main fire pump.
The electric-versus-diesel decision should focus on the reliability and suitability of the main pump's driver. The jockey pump decision should focus on pressure maintenance, system behavior, pump sequencing, and the conditions under which the main fire pump should respond.
And as fire pump technology moves toward greater automation, remote testing, connectivity, and smarter pressure management, engineers will increasingly need to evaluate the entire pumping system rather than individual pumps in isolation. The latest NFPA 20 developments reinforce this broader approach by addressing automated testing, remote monitoring, connectivity, controller arrangements, and pressure-maintenance terminology
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