Does Every 2½" Hose Valve Always Need 100 psi?

3/31/2025

NFPA 14 states that "hydraulically designed standpipe systems shall be designed to provide the waterflow rate required by Section 7.10 at a minimum residual pressure of 100 psi at the hydraulically most remote 2½" hose connection and 65 psi at the outlet of the hydraulically most remote 1½" hose connection" (Section 7.8.1, 2019 edition).

So does this mean if you have a single 2½" hose valve on your project, you need 100 psi residual at that valve?

This seems pretty cut and dry, but I've been thinking about this, and off the top of my head, I can list at least 5 projects that had 2½" hose valves and less than 100 psi of static pressure on the ground floor, let alone 100 psi residual on the 4th floor.

Not only projects that I have personally witnessed get signed off, but also buildings I have found myself walking through that have had gauges on the hose valves, and those gauges more often than not (in my area at least) read a pressure less than 100 psi static.

Are these just all designed wrong?

Or am I missing something?

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9 Comments

Brett

3/31/2025 06:49:08 am

How tall were those buildings? It sounds like those projects may have had manual standpipes which means the fire department's pump would be the one boosting the pressure of the system.

danefre

3/31/2025 07:29:28 am

Read about automatic vs manual standpipes.

There are some conditions that trigger automatic standpipes, most commonly high-rises per IBC (not grandfathered-in, not in NYC). In those buildings you should definitely be seeing 100psi at the topmost, most remote hose valves.

Taylor Schumacher

3/31/2025 08:28:28 am

Sounds like you are looking at manual wet standpipes.

Jesse

3/31/2025 08:33:47 am

I think you may be looking at manual a wet-standpipe system. While this may be interconnected to the AS system, a fire department apparatus is required to supply the system to operating pressure. As such, the static pressure on the system isn't of much relevance.

Glenn Berger

3/31/2025 08:51:21 am

The design needs to account for 100 psi at the most remote outlet. This can be achieve via the pump on a fire truck as is typically for a manual-wet standpipe system. Placard needs to be provided for the responding fire department to achieve the required pressure.

Jack G

3/31/2025 08:52:42 am

It s probably a manual wet standpipe system where the fire department supplies the pressure and flow to the standpipe system.
Amount of stories is relevant and whether it’s a new building or an existing building has relevance to whether it can be a manual wet standpipe system. Review the IBC for requirements also.

Dan Wilder

3/31/2025 08:56:56 am

There are also provisions within NFPA 13, 16.15.2.1-19 Ed. for adding 2½" hose valves (not typically in buildings over 30' as that is the trigger for standpipes).

As others have stated, this sounds more like a manual (wet?) standpipe that would be allowed within buildings 30'-75' in height per Section 905.3.1 (IFC 2021 Ed.)

Matthew Mueller

4/1/2025 09:55:34 am

Regarding the 100 psi minimum, it's important to remember the historical context. Prior to the early 2000s, BOCA standards, a predecessor to the IBC, (as well as NFPA 14 if I am correct) specified a minimum of 65 psi. This was based on the smooth bore nozzles used by the fire service until the 80s/90s.

NFPA 25, section 6.3.4.1, requires that 'The standpipe system demand shall be based on the design criteria in effect at the time of the installation.' This often presents a practical challenge during flow testing, as the original design specifications are frequently unavailable.

While NFPA 25 allows for the AHJ to determine the demand in such cases, they are often reluctant to specify values for systems installed before their time. Consequently, reconciling historical standards with current testing requirements is a real challenge.

Dave L.

4/7/2025 10:15:20 am

Note that for hose stations that are NOT part of an NFPA 14 standpipe system, requirements may vary.

Does Every 2½" Hose Valve Always Need 100 psi?

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