Water Supply · Trigger
When Is a Jockey Pump, Bypass or Test Header Required?
Reviewed by a licensed Professional Engineer · NY, NJ, PA, MD, DE · Last reviewed · Code basis: NFPA 20 Ch 4 and Ch 14 (2016 as modified by 2022 NYC BC Appendix Q Q106; 2025 in DE; IBC-referenced edition elsewhere); NFPA 25 (2023) Ch 8
General guidance, not a code determination for any project. Confirm the adopted code and local amendments with the authority having jurisdiction.
A fire pump needs a jockey pump where the system is held at a standby pressure above what the water supply provides, a bypass where the suction supply has enough pressure to be of material value without the pump, and a test header or flowmeter on every installation so the pump can be flow-tested to 150 percent of its rated flow. All three rules sit in Chapter 4 of the National Fire Protection Association (NFPA) standard for stationary fire pumps, NFPA 20. None of the three is triggered by building size or occupancy; each follows from the hydraulics of the supply and the system.
This article sets out the condition for each device, how the design team checks it from the flow test and the pump data, and what each device brings with it once it is required. A worked example for a 750 gpm pump on a 60 psi supply carries the numbers through, and a jurisdiction table covers New York, New Jersey, Pennsylvania, Maryland and Delaware.
At a Glance: Jockey Pump, Bypass and Test Header
- Threshold(s) with units: jockey pump where the system standby pressure (commonly the pump’s churn pressure plus the minimum static supply pressure, 140 psi in the worked example) sits above the supply’s static pressure (60 psi in the example); bypass where the supply’s pressure is of material value with the pump off, the usual case on a pressurized main; test header or flowmeter on every fire pump, able to flow 150 percent of rated flow (1,125 gpm for a 750 gpm pump).
- Code, edition, section: NFPA 20 Chapter 4 (pressure maintenance pumps, bypass and water flow test devices), in NFPA 20 (2016) as modified by the 2022 New York City (NYC) Building Code Appendix Q, Section Q106, NFPA 20 (2025) in Delaware, and elsewhere the edition referenced by the adopted International Building Code (IBC); NFPA 25 (2023) Chapter 8 for the annual test that uses the header or meter, with the annual frequency in Section 8.3.3.
- Main exceptions: a flowmeter loop as the test device; another means of pressure maintenance on a small, low-leakage system where the authority having jurisdiction (AHJ) accepts it; no bypass where the suction pressure is negligible, such as a suction tank at grade.
- What applies once triggered: jockey pump start and stop settings above the fire pump start, a check valve and isolation valves on the jockey pump, a bypass commonly fitted with a check valve and control valves, a header usually at an exterior wall or outside, with a control valve and drain on its supply where it is exposed to freezing, flowmeter calibration, and supervised control valves.
- Permit or filing: shown on the fire pump, sprinkler or standpipe permit drawings; in NYC, the Department of Buildings (DOB) filing that carries the fire pump, built to the DOB stationary fire pump requirements sheet; in Delaware, State Fire Marshal plan review.
- Who decides: the design team proposes the arrangement; the AHJ approves it and witnesses, or accepts the witness of, the acceptance test.
What Conditions Trigger a Jockey Pump, Bypass or Test Header?
Each device answers a different question about the fire pump. The jockey pump answers how the system holds pressure between fires, the bypass answers how the supply reaches the system when the pump is off or isolated, and the test header or flowmeter answers how the pump proves its curve. The table gives the condition for each device, the units it is judged in and the code basis.
| Device | Required where | Judged in | Code basis |
|---|---|---|---|
| Pressure maintenance (jockey) pump | The system is held at a standby pressure above the supply’s static pressure and the fire pump starts on a pressure drop; the fire pump itself may not be used to maintain system pressure | psi: standby pressure against the minimum static supply pressure | NFPA 20 Chapter 4 |
| Bypass around the fire pump | The suction supply has enough pressure to be of material value to the system with the pump off; the usual case is a pump on a pressurized public main or private fire service main | psi and gpm: what the supply alone delivers into the system | NFPA 20 Chapter 4 |
| Test header (hose valve header) | Every fire pump needs a way to be flow-tested to 150 percent of rated flow; a header of 2.5 in. hose valves is the usual way, with the outlet count taken from a table keyed to rated capacity | gpm: 150 percent of rated flow | NFPA 20 Chapter 4 |
| Flowmeter loop | A listed metering arrangement accepted as the test device, alone or alongside a header, for the same 150 percent test | gpm: a meter capacity beyond 150 percent of rated flow | NFPA 20 Chapter 4; NFPA 25 (2023) Chapter 8 for its use in annual tests |
| NYC relief valve | Every automatic fire pump: a 3 in. National Pipe Thread (NPT) pressure relief valve on the discharge, set to open below the pump’s shutoff head and above the pressure needed at the highest hose valve | psi: shutoff head and top hose valve pressure | NFPA 20 (2016) Section 4.13.1.1.9 as added by 2022 NYC Building Code Appendix Q, Section Q106 |
| NYC acceptance flow test | The flow test runs through the pump test connection with water flow test devices, pitot readings at each nozzle where pitot gauges are used, and the pressure at the test header recorded for each flow | gpm and psi at each test point | DOB stationary fire pump requirements sheet; DOB guidance |
The jockey pump and the bypass are judged against the same number: the static pressure of the supply. A strong public main makes the bypass worth having and leaves a smaller gap for the jockey pump to fill, while a suction tank at grade has almost no pressure to bypass and leaves the whole standby pressure to the pump set. The test header is different, because NFPA 20 Chapter 4 requires every fire pump to have a test arrangement sized for 150 percent of rated flow, whatever the supply.
This article starts from a pump that has already been selected. How the rated flow, rated pressure and 150 percent point are chosen is covered in how a fire pump is sized for rated flow and pressure.
Figure 1: Where the Jockey Pump, Bypass, Test Header and Flowmeter Connect
How Does the Design Team Determine Which Devices a Fire Pump Needs?
Three checks settle the question, and all three use data the design team already holds: the hydrant flow test or tank data, the pump’s rated flow and churn (shutoff) pressure, and the system’s pressure needs. None of the three calls for a separate test; each is a comparison of numbers already on the drawings.
- Compare the standby pressure with the supply’s static pressure. In common practice the system is held at about the pump’s churn pressure plus the minimum static supply pressure, so the system already sits at the pressure the fire pump would produce at no flow. If that standby pressure is above what the supply alone holds, something has to keep the system there between fires. NFPA 20 Chapter 4 does not let the fire pump do that job, so a jockey pump or another accepted means is needed.
- Check whether the supply alone delivers useful flow. Compare the flow test with the demand of the lower part of the system, pump off. A public main at 60 psi static can usually feed sprinklers on the lower floors by itself, which makes its pressure of material value and calls for a bypass under NFPA 20 Chapter 4. A suction tank at grade, with a few psi of head, usually does not; the design team makes the call with a short hydraulic check and the AHJ accepts it.
- Size the test arrangement from the rated flow. The header has to pass 150 percent of rated flow. The number of 2.5 in. hose valves comes from a table in NFPA 20 Chapter 4 keyed to rated capacity, and the count rises in steps rather than in direct proportion to flow; the commonly cited value for a 750 gpm pump is three. The header supply pipe is sized from the same table, with a larger pipe where the run from the pump discharge to the header is long.
Figure 2: Which Devices Does This Fire Pump Need?
Worked Example: A 750 gpm Pump on a 60 psi Main
A sprinklered building is served by a 750 gpm electric fire pump drawing from a public main. The hydrant flow test shows 60 psi static, taken here as the minimum static pressure, and the selected pump has a churn pressure of 80 psi. The table applies the three checks; the pressure settings and jockey pump capacity are common practice, not code values.
| Check | Numbers | Result |
|---|---|---|
| Standby pressure | 80 psi churn + 60 psi static = 140 psi, against a supply that holds 60 psi | Jockey pump required: the 80 psi gap has to be held without running the fire pump |
| Jockey pump stop (practice) | Churn plus minimum static: 140 psi | Below the 175 psi rating common for system components |
| Jockey pump start (practice) | 10 psi below the stop: 130 psi | Gives the jockey pump a working band |
| Fire pump start (practice) | 5 psi below the jockey pump start: 125 psi | Leakage is handled by the jockey pump; a real flow drops the system past 125 psi and starts the fire pump |
| Jockey pump capacity (practice) | Makes up the allowable leakage rate within about 10 minutes, or 1 gpm, whichever is larger; one K-5.6 sprinkler discharges about 66 gpm at 140 psi | A pump of a few gpm, far below the flow of one open sprinkler, so a single sprinkler still pulls the system down to the fire pump start |
| Bypass | 60 psi static feeds the lower floors with the pump off | Required: the supply’s pressure is of material value |
| Test flow | 750 gpm × 1.5 = 1,125 gpm | Header and any flowmeter sized for 1,125 gpm |
| Hose valves | Table in NFPA 20 Chapter 4, read at the 750 gpm rating | Three 2.5 in. hose valves, the commonly cited table value; about 375 gpm per outlet at 1,125 gpm |
In common practice the settings stack in this order. The jockey pump stops at the top of the band and restarts 10 psi lower, and the fire pump starts 5 psi below that, so small leaks never reach the fire pump start point. If the jockey pump fails, the system bleeds down toward the 60 psi the main holds, crosses 125 psi and starts the fire pump, which is why a fire pump that starts with no flow often points to the jockey pump.
The jockey pump and fire pump controllers carry these set points, and how the fire pump stops after a start is a controller setting rather than a piping decision. A larger pump changes the arithmetic but not the order: the test flow is always 1.5 times rated flow, and the jockey pump band always sits above the fire pump start.
DGA designs fire pump installations, including the pressure maintenance, bypass and test arrangements, across New York, New Jersey, Pennsylvania, Maryland and Delaware. Project briefs get confirmation and preliminary code feedback within one business day. See where DGA works →
What Exceptions and Alternatives Apply?
A flowmeter loop in place of hose streams. NFPA 20 Chapter 4 accepts a listed metering arrangement as the test device, and a loop that returns water to the pump suction lets the annual test run without discharging 1,125 gpm onto the site. A closed loop does not prove the water supply, because the same water circulates past the meter. NFPA 25 (2023) Chapter 8 therefore still calls for a test that discharges water at least once every 3 years, which is why many designs keep a header or a meter discharge to drain alongside the loop.
No jockey pump on a small, tight system. NFPA 20 Chapter 4 bars the fire pump from maintaining system pressure and sets rules for a pressure maintenance pump where one is installed, but it does not make a jockey pump mandatory on every system. On a small aboveground system with low leakage, some AHJs accept another means, such as a pressure tank, and the jockey pump is left out. The design team gets that acceptance in writing before the pump set is ordered, because the default expectation at plan review is a jockey pump.
No bypass on a low-pressure suction. Where the pump draws from a suction tank at grade, or from a supply whose static pressure does little for the system, the bypass is left off. NFPA 20 Chapter 4 ties the bypass to supply pressure of material value, not to every pump. If the supply alone cannot deliver meaningful flow to the lowest sprinklers, a bypass adds valves without adding protection.
A main relief valve is not an alternative. A relief valve cannot stand in for a right-sized pump or a pressure maintenance arrangement. NFPA 20 Chapter 4 provides a main pressure relief valve mainly for diesel drives and variable speed control, and a relief valve is not a substitute for selecting a pump whose churn pressure suits the system’s component ratings. New York City adds its own relief valve on every automatic fire pump through Appendix Q, but that valve is a local requirement, not a fix for pump selection.
What Applies Once Each Device Is Required?
Each device brings a short list of installation rules, collected in the table with their code basis. The room that holds the equipment, its fire rating and its drainage are covered in what NFPA 20 requires of a fire pump room.
| Device | What applies | Basis |
|---|---|---|
| Jockey pump | Its own controller, with start and stop points above the fire pump start; its own pressure sensing line; a check valve on the discharge; isolation valves so the pump and check valve can be serviced; rated for the system’s normal leakage, not the fire demand; not required to be a listed fire pump | NFPA 20 Chapter 4; set points and the 10-minute sizing are practice |
| Bypass | Commonly a check valve so the pump’s discharge cannot recirculate to the suction, with control valves for maintenance; at least as large as the discharge pipe the standard lists for the pump’s rating | NFPA 20 Chapter 4 |
| Test header | Usually on an exterior wall or outside, where 150 percent of rated flow can run off without damage; where an outside header is exposed to freezing, a control valve near the pump and a drain in the header supply line; capped 2.5 in. outlets; a supply pipe one size larger on a long run | NFPA 20 Chapter 4 |
| Flowmeter | Listed, with a capacity beyond the 150 percent test point (the standard’s minimum is commonly cited as 175 percent of rated flow); isolation valves; calibration so annual readings can be trusted | NFPA 20 Chapter 4; NFPA 25 (2023) Chapter 8 |
| Valve supervision | Control valves on the suction, discharge and bypass lines supervised in their normal position | NFPA 20 Chapter 4 |
| Testing | Annual flow test at churn, rated flow and 150 percent of rated flow through the header or meter | NFPA 25 (2023) Chapter 8; annual frequency in Section 8.3.3 |
The header and meter earn their place at the tests. The acceptance test under NFPA 20 Chapter 14 flows the pump at churn, rated flow and 150 percent of rated flow through them, as described in what happens at a diesel fire pump acceptance test, and the annual test under NFPA 25 (2023) Section 8.3.3 repeats the exercise each year. Reading the results against the manufacturer’s curve, with the speed correction, is covered in how to read a speed-corrected fire pump test curve.
How Do NY, NJ, PA, MD and DE Apply These Rules?
The device rules are NFPA 20 Chapter 4 everywhere; what changes by jurisdiction is the edition, the filing and, in New York City, local additions. The table lists the edition each jurisdiction runs, the AHJ and filing, and the local rules confirmed for these devices.
| Jurisdiction | NFPA 20 edition | AHJ and filing | Local rules for these devices |
|---|---|---|---|
| New York State (outside NYC) | Edition referenced by the 2024 IBC, through the 2025 Uniform Code | Local code enforcement official; building permit with the fire pump on the sprinkler or standpipe submittal | None beyond NFPA 20 identified for these devices |
| New York City | NFPA 20 (2016) as modified by 2022 NYC Building Code Appendix Q, Section Q106 | DOB; the filing that carries the fire pump follows the DOB stationary fire pump requirements sheet; the field acceptance test has the permit holder present and may be witnessed by a DOB inspector or a certified professional (DOB guidance) | 3 in. NPT relief valve on each automatic fire pump, set below shutoff head and above the pressure needed at the highest hose valve, with discharge allowed back to the pump suction through a sight glass (Section 4.13.1.1.9 as added); water drained or supplied from a fire pump may not discharge into a potable water source (Section 4.6.2.1.2 as added); flow test through the pump test connection with pitot readings at each nozzle where pitot gauges are used (DOB requirements sheet). Q106 also amends other Chapter 4 sections, so a New York City layout is checked against the full Appendix Q list. |
| New Jersey | Edition referenced by the 2024 IBC, through the Uniform Construction Code (UCC) | Municipal construction official and fire protection subcode official; UCC fire protection subcode permit; the Uniform Fire Code (2018 International Fire Code basis) governs existing buildings | None beyond NFPA 20 identified for these devices |
| Pennsylvania | Edition referenced by the 2021 IBC, through the UCC; no statewide fire code | Municipal or third-party code official; Philadelphia Department of Licenses and Inspections (L&I) in the city; building permit | None beyond NFPA 20 identified for these devices |
| Maryland | Edition referenced by the 2021 IBC for the county permit; NFPA 1 (2024) as the State Fire Prevention Code | County building official and fire marshal; fire marshal permits under NFPA 1 at the AHJ’s discretion (Code of Maryland Regulations (COMAR) 29.06.01.08) | None beyond NFPA 20 identified for these devices |
| Delaware | NFPA 20 (2025), with NFPA 25 (2023), by Regulation 701 (2026) | State Fire Marshal plan review (1 Del. Admin. Code 701); county building permit | None beyond NFPA 20 identified for these devices |
Delaware and New York City name their NFPA 20 editions directly. Elsewhere the edition follows the building code’s referenced standards, so a project in New Jersey and one in Pennsylvania can be reviewed to different editions of the same chapter. Section numbers move between editions, so the drawings cite the edition the AHJ adopted.
Red flags on a fire pump submittal: a jockey pump with no check valve or isolation valves; jockey pump and fire pump set points that overlap; a bypass with no check valve; a test header that discharges inside the building; a closed flowmeter loop with no other way to discharge water; and, outside New York City’s local rule, a main relief valve on an electric pump offered as the cure for excess churn pressure.
Key Takeaway: Every fire pump needs a test header or flowmeter able to flow 150 percent of rated flow. A jockey pump is needed where the system is held above the supply’s static pressure, and the fire pump may never do that job; a bypass is needed where the supply’s pressure is of material value with the pump off. All three rules are in NFPA 20 Chapter 4, and the 750 gpm example sets the jockey pump at 140 psi stop and 130 psi start, the fire pump start at 125 psi, and three 2.5 in. hose valves on the header.
Frequently Asked Questions
Does NFPA 20 require a jockey pump?
Conditional: NFPA 20 Chapter 4 does not require a jockey pump by name, but it does not allow the fire pump to maintain system pressure. Where the system is held above the supply’s static pressure and the pump starts on a pressure drop, some accepted means of pressure maintenance is needed, and a jockey pump is the usual one.
When does a fire pump need a bypass?
When the suction supply has enough pressure to be of material value to the system with the pump off, which is the usual case for a pump on a pressurized public main (NFPA 20 Chapter 4). A pump drawing from a suction tank at grade usually does not need one, because the tank’s head alone does little for the system.
How many hose valves does a fire pump test header need?
Conditional: the count comes from a table in NFPA 20 Chapter 4 keyed to the pump’s rated capacity. For a 750 gpm pump the commonly cited count is three 2.5 in. hose valves, and the count rises in steps with larger pumps rather than in direct proportion to flow.
Can a flowmeter loop replace the test header?
Conditional: NFPA 20 Chapter 4 accepts a listed metering arrangement as the test device, and a loop back to the suction saves water at each annual test. A closed loop does not prove the water supply, so NFPA 25 (2023) Chapter 8 still calls for a test that discharges water at least once every 3 years, and in New York City the acceptance test is flowed through the pump test connection using water flow test devices, with pitot readings at each nozzle where pitot gauges are used.
Does a New York City fire pump need a relief valve?
Yes. Appendix Q of the 2022 NYC Building Code adds a 3 in. relief valve on the discharge of every automatic fire pump, set to open below the pump’s shutoff head and above the pressure needed at the highest hose valve, with its discharge allowed back to the pump suction through a sight glass. The valve is a local addition and does not take the place of the jockey pump, the bypass or the test header.
More in Water Supply
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- Water Supply for Fire Protection: The Complete Guide
- What Is a Fire Pump Controller and Transfer Switch?
- When Can a Well or Private Source Supply Fire Protection?
- What Is Backflow Preventer Pressure Loss in Sprinkler Calcs?
- Split-Case vs In-Line vs Vertical Turbine: Which Fire Pump?
This article is general information, not a substitute for a project-specific fire pump design. Code editions, local amendments and reviewer practice change; confirm the adopted edition and the authority having jurisdiction for each project.
Need the Fire Pump Piping Laid Out?
Send the hydrant flow test, the pump’s rated flow and churn pressure, and the jurisdiction. DGA checks whether the system needs a jockey pump and a bypass, sets the pressure settings and lays out the test header or flowmeter for the permit set. Project briefs get confirmation and preliminary code feedback within one business day.