When designing or operating a fire protection system, one of the most critical parameters is the starting pressure of a fire pump. Setting the correct start pressure ensures that your fire pump activates automatically, delivers sufficient water flow and pressure during a fire emergency, and complies with NFPA 20 or other regional standards.
In this article, we’ll cover everything you need to know about fire pump starting pressure, including industry guidelines, calculation methods, influencing factors, common mistakes, and best practices.
Fire pumps are designed to boost water pressure in fire protection systems when the available water supply cannot maintain adequate flow and pressure.
The starting pressure refers to the set point at which the fire pump automatically starts operating.
If the system pressure drops below this set value, the pump starts.
When the pressure recovers above the stop point (usually controlled by the jockey pump), the fire pump stops.
Setting the correct starting pressure is vital because:
Too low → delayed pump activation, risking insufficient water supply.
Too high → unnecessary pump starts, leading to wear, energy waste, and system damage.
The NFPA 20 Standard for the Installation of Stationary Pumps for Fire Protection provides widely accepted guidance on fire pump pressure settings. While NFPA 20 does not specify a fixed start pressure, it defines the principle:
“The fire pump shall start automatically at a pressure below the jockey pump stop pressure but above the minimum system demand pressure.”
Key takeaways from NFPA 20:
Fire pump start pressure must always be lower than the jockey pump stop pressure.
Fire pump start pressure should maintain positive system pressure before sprinkler heads open or hydrants operate.
Fire pump start pressure should not trigger unnecessarily during normal system fluctuations.
In most fire protection systems, a jockey pump (or pressure maintenance pump) works alongside the main fire pump.
Jockey Pump Function → Maintains normal system pressure, compensating for small leaks.
Fire Pump Function → Activates during significant pressure drops caused by sprinkler activation or hydrant use.
Typical pressure setting example:
Jockey pump start: 110 psi
Jockey pump stop: 130 psi
Fire pump start: 100 psi
This ensures the fire pump only runs when needed.
Setting the right starting pressure involves several steps:
Calculate the minimum pressure needed at the highest sprinkler or hydrant.
Include friction losses, elevation, and hose allowances.
Normally, set 10–15 psi above the required system pressure.
Set the fire pump start pressure 5–10 psi below the jockey pump stop pressure.
Perform a flow test to verify activation timing and ensure adequate water supply.
Several variables influence the ideal fire pump starting pressure:
Systems requiring higher operating pressures, such as high-rise buildings, need higher start settings.
If the municipal water supply is stable, the starting pressure can be set higher.
If supply fluctuates, a lower start pressure may be required.
Wet Pipe Systems → Higher starting pressure to maintain pipe fill.
Dry Pipe Systems → Different activation dynamics, requiring separate calculations.
In tall buildings, every 2.31 ft of elevation adds 1 psi requirement.
While NFPA 20 is widely followed, some regions have local fire codes with specific pressure requirements.
Incorrectly setting start pressure can lead to serious performance and maintenance issues:
Starting too low:
Delayed response during fire emergencies.
Inadequate water delivery to upper floors.
Starting too high:
Frequent, unnecessary pump starts.
Increased wear and tear on motors, bearings, and seals.
Ignoring jockey pump coordination:
Causes the fire pump to run when only minor leaks occur.
Not testing under real conditions:
Settings must be verified with a full system test, not just theoretical calculations.
| System Type | Required System Pressure | Jockey Pump Stop | Fire Pump Start |
|---|---|---|---|
| High-rise office | 130 psi | 140 psi | 130 psi |
| Industrial warehouse | 100 psi | 110 psi | 100 psi |
| Residential complex | 80 psi | 90 psi | 80 psi |
| Hospital facility | 120 psi | 130 psi | 120 psi |
Tip: Always confirm settings during commissioning and after maintenance.
Fire pump controllers must be tested during installation to verify automatic activation.
Testing steps:
Open the test header → Simulate sprinkler or hydrant demand.
Monitor pressure drop → Ensure pump starts before system pressure reaches minimum safe level.
Verify jockey pump control → Jockey pump should handle small leaks without triggering the main pump.
Record performance data → Log start/stop pressures for future reference.
NFPA 25 recommends testing fire pumps weekly (electric) and monthly (diesel) to ensure proper functionality.
Follow NFPA 20 or local standards strictly.
Keep a 5–10 psi gap between jockey pump stop and fire pump start.
Perform annual flow tests to confirm performance.
Adjust settings when system modifications occur.
Keep detailed maintenance logs for audits and inspections.
Setting the correct starting pressure for your fire pump is critical for ensuring reliable fire protection, NFPA 20 compliance, and equipment longevity.
By properly coordinating the jockey pump and fire pump start settings, you can prevent unnecessary pump cycles, reduce wear, and guarantee sufficient pressure during emergencies.
If you’re designing or upgrading a fire pump system, working with a trusted manufacturer ensures your system meets the latest safety standards and performs reliably when it matters most.
