Does NFPA 13 Require Redundant PRVs?

4/3/2026

NFPA 14 requires PRV redundancy when more than two hose connections are supplied downstream of a PRV.

Does NFPA 13 have a similar requirement for sprinkler systems, or can multiple sprinkler systems be controlled by a single PRV?

We are proposing to feed a riser manifold controlling (6) sprinkler systems to be supplied by a single ORV without a redundant loop.

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8 Comments

Dan Wilder

4/3/2026 07:57:02 am

Not specifically called out in 16.9.7 (13-25) for Pressure-Reducing Valves.

It kinda makes sense as there is no direct human interaction with a sprinkler system so other than a pressure overage (not per listings and maybe distribution pattern interruption at the higher pressure), nothing else is really affected.

However, wouldn't you be providing a low flow bypass for a single sprinkler activation vs the entire system demand? Is the cost of the additional valve worth not having to take down 6 zones in case of failure (the fire watch costs alone would offset the cost of the valve had it been installed in the first place, not to mention impact to the property as a whole)?

Jesse

4/3/2026 08:25:12 am

I was wondering if I was understanding the issue as intended because I agree with Dan's point. I think this could impair all systems.

Jose Figueroa

4/3/2026 11:13:00 am

Yes, this makes sense in principle. However, I need more details: if you share the specific NFPA edition you’re working with, the building height or occupancy type, or whether this system is a combined standpipe and sprinkler setup, I can help narrow it down further. In most standalone sprinkler applications, your single-PRV manifold approach aligns with NFPA 13.

Be aware that the AHJ, insurance providers like FM Global, or building codes such as certain high-rise provisions in the IBC may require additional measures, such as redundancy in series for master PRVs serving multiple zones or floors, especially in tall buildings or where failure could cause overpressure in large parts of the system. FM Global data sheets, for example, discuss arrangements for PRVs in sprinkler systems but do not reflect NFPA 14’s hose-connection limits.

If this system is insurable by FM, please contact FM Engineering. Refer to Data Sheet 3-11 (Pressure Reducing Valves for Fire Protection Services and related guidelines in Data Sheet 2-0 (Installation Guidelines for Automatic Sprinklers).

4/3/2026 04:07:02 pm

2022-NFPA 13, CBC 2022, Non-FM Global. I have a horizontal riser manifold, feeding (6) sprinkler risers (on the same floor), in a high-rise (4) story building. The proposal is to install a single PRV prior to the first riser instead of installing (6) individual PRV valves, which would be a single PRV for each system.

4/3/2026 04:12:12 pm

Standpipe system is separate of the horizontal riser manifold and will not be controlled in this instance.

Jose Figueroa

4/3/2026 05:25:16 pm

@OP

NFPA 13 (sprinklers): Allows a single listed PRV to supply multiple systems/zones from a common supply, as long as components are protected, full-flow testing is possible, and relief is provided where needed. The AHJ may consider individual PRVs at each floor control assembly (downstream of a common supply control valve) for the high-rise. Install approved/listed equipment and document any possible deviation to standards. I took note of your observation with respect to the separated standpipe.

Jack G

4/3/2026 04:51:54 pm

The PRV and riser manifold would be sized for the 6 sprinkler risers on that floor.
As Dan indicates a second prv — parallel— sized for a sprinkler head flow is needed to permit the low flow to a single sprinkler head, the first prv ( if installed alone ) might permit too many heads opening and overflow the design area / pipe sizes.

Jose R Figueroa

4/6/2026 01:28:49 pm

Between 2021 and 2023, I inspected several large warehouses where the sprinkler systems were supplied by high static municipal water pressure. Each building's main line had OS&Y valves, double-check valves (backflow preventers), and a PRV that served multiple sprinkler zones. Hydraulic calculations were verified for each zone. I see no reason why additional sprinkler heads would open prematurely due to the single PRV.

Could you explain why more heads would open unless a fire is out of control? I might have missed something.

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Does NFPA 13 Require Redundant PRVs?

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