Shared Fire Line Monitored by Only One Building?

3/26/2025

Before people say, "Ask the AHJ," I am him; he is me.

I have an applicant who has combined plots of land with a mid-rise and some detached townhouses. A shared fire line supplies the two structures, but only the mid-rise FACP monitors the supply tamper.

The townhouse FACP will not know if the water is off (except for the tampers at the risers within the townhouse).

The buildings are owned by the same ownership. They are arguing they are technically meeting IBC 2015 903.4 "Valves controlling the water supply for automatic sprinkler systems, pumps, tanks, water levels, and temperatures, critical air pressures, and waterflow switches on all sprinkler systems shall be electrically supervised by a listed fire alarm control unit."

It is being monitored, but the fire marshal and I are of the opinion this doesn't provide monitoring for the townhouse and does not meet the intent of the code.

Does anyone have any thoughts on whether a shared line can be monitored by only one building that it serves?

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6 Comments

Glenn Berger

3/26/2025 08:12:49 am

If the alarms from this one FACP are being transmitted to constantly attended location then in my opinion that would be acceptable.

Dan Wilder

3/26/2025 08:57:14 am

Our AHJ's would not allow this as ownership can change to easily creating one property to be dependent on another for the water supply for connected properties. Their justification is that selling either property would not trigger a building and fire code review that would identify the shared service however trying to split a single parcel would, due to ROW and Utility requirements.

You could use 2021 IFC 507.1 for an "approved" water supply, but that would also lead to needing something that would not allow this setup.

If this is a private fire service PRIOR to the fire line split with that single valve controlling both, then you could use your adopted NFPA 24 and reference (this is 2025 section)
6.2.9 - All connections to private fire service mains for fire protection systems shall be arranged in accordance with one of the following so that they can be isolated.

Have multiple structures without an ability to individually isolate and monitor them could be a violation of this section.

If each building has dedicated fire alarm capabilities, why were the townhomes exempted from the monitoring point and can it be added? Could this be the easy solution vs expensive UG modifications?

J.H.

3/26/2025 09:57:03 am

What does your adopted Fire Code require? All valves are required to be supervised under the provisions of NFPA 1:13.3.1.8 Supervision, and also NFPA 24:6.7.2.

The Townhome supply control valves should be reporting to the Townhome FACP. Since this is a shared private fire line, all control valves upstream of the respective Points of Connection need to be supervised and report to the affected bldg's FACP.

If there is not a Townhome supply control valve, one needs to be installed in compliance with NFPA 24:6.2.9.
You haven't mentioned the FDC situation, but each bldg's. FDC must also be connected inside the respective supply control valves.

I recommend consulting with Planning & Zoning to see if there are any Land Development Code requirements to consider, since it sounds like these are separate parcels.

Chad

3/26/2025 10:39:36 am

“It is being monitored, but the fire marshal and I are of the opinion this doesn't provide monitoring for the townhouse and does not meet the intent of the code.”

I can see this going both ways, but since you said it does not meet the intent of the code what would in your mind? Depending on the distances between the common valve and the buildings. Potter makes a wireless device that could transmit it to Both buildings…. you would need one transmitter for each building, and virtually every single sprinkler supervisory/tamper switch has a DPDT output.

Jesse

3/26/2025 10:52:42 am

Agree with Glenn and Dan on this one. Yeah, the if the tamper transmits to a continuously attended location then no problem.

But Dan's comment about if part of the property were sold is a very real issue. But then, who owns the tampers and who is responsible for maintenance and testing???

I think I owuld make the townhomes monitor it as well

Jack G

3/26/2025 11:10:21 am

One service for 2 properties is not ideal but is allowed.
Shutting off 2 properties with 1 valve is not a good idea either..
IBC 903.3.1.5 restricts one service for 2 buildings ( except if approved by the AHJ—- there you go )
The restriction is there to ensure that a fire in one building does not compromise the water supply and fire protection to the other buildings connected to the same riser.
For 2 buildings connected to a single water supply, NFPA 72 requires each building has its own fire alarm system, ( each has its own FACU) and that they function as a single fire alarm system meaning they must be interconnected and share a common control panel.
The FACU in each building should have its own remote annunciators that display alarm conditions in the other buildings FACU locations and both systems should allow for resetting and silencing alarms from any panel.
72 .23.8.2.1, and 72.23.8.2.2.
Also MeyerFire 3/7/2023 discussion.

Shared Fire Line Monitored by Only One Building?

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