1. The jockey pump’s role and the limit on its size
NFPA 20 defines the jockey pump as a pump designed to maintain the pressure on the fire protection system between preset limits when the system is not flowing water. NBR 13714 and Goiás NT 22 describe the same role for the pressurization pump: centrifugal hydraulic equipment intended to keep the system pressurized within a preset range. In the hydrant and hose reel rules, it serves to make up small network pressure losses.
Where the contract adopts NFPA 20, every pressure-actuated fire pump needs a means of maintaining system pressure: a jockey pump, a water mist positive displacement pumping unit in accordance with 8.5.7.2, or another approved means that is not the main fire pump (4.27.1). The primary or standby fire pump must not be used as a jockey pump, except as Chapter 8 permits (4.27.7).
The annex adds that a jockey pump is usually required with automatically controlled pumps and that, in a dual-purpose water supply system, a domestic water pump can serve as the means of maintaining pressure.
The jockey pump’s limit is its size. Under the NFPA 20 annex, where it serves only aboveground piping for sprinkler and standpipe systems, it should be sized to provide a flow less than a single sprinkler. The main fire pump should start and run, providing a pump running signal, for any waterflow situation where a sprinkler has opened, which will not happen if the jockey pump is too large.
For that reason, a persistent pressure drop calls for investigating the network, not a larger jockey pump: with a flow above that of one sprinkler, the jockey pump would start supplying a real opening, and the main pump would not start.
Note
NFPA 20 treats the jockey pump differently from the main fire pump: it is not required to be listed, but it must be approved by the authority having jurisdiction (4.27.2 and 4.27.2.1), and it is not required to have alternate or standby power (4.27.9).
2. Flow and pressure: allowable leakage, not a percentage of the main pump
Where the contract adopts NFPA 20, the jockey pump is sized to replenish the system pressure lost through allowable leakage and normal pressure drops (4.27.2.2), with a rated capacity not less than any normal leakage rate (4.27.3) and enough discharge pressure to maintain the desired system pressure (4.27.4).
The annex explains that sizing requires an analysis of the type and size of the system served: jockey pumps on systems with large underground mains need to be larger than those on small aboveground systems, because NFPA 24 permits some leakage in underground mains, while aboveground piping is required to be tight when new.
One guideline that the annex records as successfully used is to select a pump that will make up the allowable leakage rate in 10 minutes or 1 gpm (3.8 L/min), whichever is larger. For aboveground-only piping, the ceiling from section 1 applies: a flow less than that of a single sprinkler.
None of these criteria starts from a percentage of the main pump flow. The rule of 1% of main pump flow circulates among designers as a practical target, but it does not appear in the NFPA 20 jockey pump provisions, in São Paulo IT 22, in Goiás NT 22 or in NBR 13714.
Applied to a 1,500 gpm main pump, it would give a 15 gpm jockey pump, about 57 L/min, almost three times the 20 L/min ceiling that these three Brazilian rules set for hydrant and hose reel networks.
In the Brazilian rules, the criterion is a maximum flow. In São Paulo and Goiás, a hydrant or hose reel network with more than six outlets takes a jockey pump, with a maximum flow of 20 L/min, and the jockey pump is waived when the fire reservoir is elevated, whatever the number of outlets (IT 22, C.1.15; NT 22, C.2.1).
NBR 13714 calls for a jockey pump when the network needs to be kept pressurized and sets the same 20 L/min ceiling (B.1.13). The jockey pump’s maximum operating pressure equals the main pump pressure measured at no flow (shutoff); in NT 22, that of the fixed booster pump (IT 22, C.1.15.1; NT 22, C.2.2; NBR 13714, B.1.13.1).
| Reference | When a jockey is used | Flow | Pressure |
|---|---|---|---|
| NFPA 20 (4.27) | Pressure-actuated pump: jockey or another approved means | Makes up allowable leakage and normal drops | Enough to maintain the desired pressure |
| São Paulo IT 22 (C.1.15) | More than six outlets, unless the reservoir is elevated | Up to 20 L/min | Maximum equal to main pump shutoff |
| Goiás NT 22 (C.2) | More than six outlets, unless the reservoir is elevated | Up to 20 L/min | Maximum equal to fixed booster pump shutoff |
| NBR 13714 (B.1.13) | When pressure needs to be maintained | Up to 20 L/min | Maximum equal to main pump shutoff |
3. Pump type, piping and valves
The rules do not set a single construction for the jockey pump. NBR 13714 and Goiás NT 22 describe it as centrifugal equipment. The NFPA 20 annex states that a centrifugal-type jockey pump is preferable, and the standard also provides for the turbine vane (peripheral) type, which requires a relief valve on the pump discharge (4.27.5.1).
Number of stages, mounting arrangement, materials and motor come from the selection for the duty point and the system water and should appear in the equipment datasheet.
A relief valve is also required when a centrifugal jockey pump operating at shutoff has a total discharge pressure exceeding the working pressure rating of the fire protection equipment; it is sized to prevent overpressuring the system (4.27.5.1). Where the jockey pump is capable of exceeding the working pressure of the fire protection system, running period timers must not be used (4.27.5.2).
For piping, NFPA 20 requires steel pipe for the jockey pump suction and discharge, including packaged prefabricated systems (4.27.6.1); an isolation valve on the suction side to isolate the pump for repair (4.27.6.3); a check valve and an isolation valve in the discharge pipe (4.27.6.4); and indicating valves where needed to make the pump, check valve and miscellaneous fittings accessible for repair (4.27.6.5).
Jockey pump valves and components are not required to be listed (4.27.6.2), and its isolation valves are not required to be supervised (4.27.6.7).
The annex notes that jockey pump suction can come from the tank filling supply line, which allows high pressure to be maintained on the system even when the supply tank is empty for repairs. In FB Bombas FBFS assemblies, the jockey pump is part of all three configurations; ask for the proposal to identify its manufacturer, model, curve, materials, motor and manual, because integration into an FB skid does not automatically make every component an FB-manufactured product.
4. Frequent starts and continuous running
Compare the jockey pump’s start frequency and running time with the acceptance records. A change in behavior may indicate a network alteration, pressure loss or a control problem, and prolonged running alone does not identify the cause.
The NFPA 25 annex on connectivity and data collection, which is informational, lists for the jockey pump the total number of starts and total running time since the last reset, the start and stop pressures and the most recent run time. Recording the same data at acceptance provides the baseline for comparison.
Before changing settings, the responsible team checks leaks, valves, water supply, instruments and pressure switches. Among the observations before the pump is operated, the NFPA 25 annex notes that suction and discharge gauge readings higher than suction pressure indicate leakage back from system pressure through either the fire pump or the jockey pump.
For signaling, São Paulo IT 22, Goiás NT 22 and NBR 13714 allow the jockey pump to have only an optical pump-running signal (IT 22, C.2.14; NT 22, C.4.11; NBR 13714, B.2.8). Define in the maintenance plan how events are recorded and faults reported, and do not adjust pressure switches or disable the system to silence an alarm without technical assessment.
5. Controls, sensing line and pressure switch settings
Under NFPA 20, the jockey pump controller must be listed, but it is not required to be listed for fire pump service (4.27.8). In every installation, including the jockey pump, each controller has its own individual pressure sensing line (4.32.1), connected between that pump’s discharge check valve and discharge isolation valve (4.32.2), in brass, rigid copper pipe Types K, L or M, or Series 300 stainless steel pipe or tube, with 1/2 in. (15 mm) fittings (4.32.3).
Where applicable, the design plans show the jockey pump and controller arrangement, including sensing line details (4.2.3.2).
In the Brazilian rules, the pressure switches on the automation manifold start and stop the jockey pump automatically and only start the main pump (in NT 22, the fixed booster pump), and they are wired to the control panels and motor starters of each pump (IT 22, C.1.15.2; NT 22, C.2.3; NBR 13714, B.1.13.2).
Once started, the main pump stops only manually, at its own control panel in the pump house (IT 22, C.1.6; NBR 13714, B.1.6); Goiás NT 22 requires manual-only stopping for the fixed or booster pump (C.1.7).
For the values, the Brazilian rules recommend a differential of approximately 10 m of water (100 kPa) between the sequential starts of the pumps (IT 22, C.1.15.1; NT 22, C.2.2; NBR 13714, B.1.13.1). For a system started by pressure drop, the NFPA 20 annex proposes the following arrangement, with the final settings established from pressures observed on test gauges:
- Jockey pump stop: main pump churn (shutoff) pressure plus the minimum static supply pressure.
- Jockey pump start: at least 10 psi (0.69 bar) below the jockey pump stop point.
- Main pump start: 5 psi (0.34 bar) below the jockey pump start point, with 10 psi (0.69 bar) increments for each additional pump.
- Where minimum run timers are provided, the pumps continue to operate at churn pressure beyond the stop setting, and the final pressures should not exceed the pressure rating of the system components.
- Where the operating differential of the pressure switches does not permit these settings, they should be as close as the equipment permits.
| Setting | Calculation | Result |
|---|---|---|
| Jockey pump stop | 115 + 50 psi | 165 psi (11.4 bar) |
| Jockey pump start | 165 − 10 psi | 155 psi (10.7 bar) |
| Fire pump stop | 115 + 50 psi | 165 psi (11.4 bar) |
| Fire pump start | 155 − 5 psi | 150 psi (10.3 bar) |
| Fire pump maximum churn | 115 + 60 psi | 175 psi (12.1 bar) |
Engineering note
The fire pump stop line in the example does not apply where the adopted rule requires manual stopping, as IT 22, NT 22 and NBR 13714 do. At acceptance, NBR 13714 requires the automation to be tested at the manifold, checking the pressure switch settings of the jockey pump (start and stop) and of the main pump (start) and the operation of the alarms (C.1.3.1). Record the actual settings and give the operator the updated diagram.