Use Intermediate Temp Throughout Warehouse?

8/22/2025

We're replacing old fire sprinkler systems in an existing warehouse in the mid-atlantic region with new ESFR systems.

The old warehouse house skylights every 25ft (which is a lot more than we see in new warehouses being built). No sprinklers are required in the skylights due to the size, however the number of skylights does raise questions about ceiling temperature.

NFPA 13, 2016 Table 6.2.5.1 shows a maximum ambient ceiling temperature of 100°F for ordinary temperature sprinklers.

It seems unlikely that the ceiling temperature would exceed 100°F in an occupied warehouse space (even on a hot summer day), so I'm thinking it make sense to install all ordinary temperature sprinklers (besides around unit heaters) to not delay sprinkler activation, but it looks like the newer editions of NFPA 13 allow of intermediate temperatures to be installed throughout warehouses.

Is anyone seeing all intermediate temperature sprinklers installed in warehouse systems to prevent accidental discharge?

NFPA 13, 2016-2025 all essentially say sprinkler temperature ratings for ESFR shall be ordinary unless Section 8.3.2 / 9.4.2 require intermediate- or high-temperature sprinklers. (Section 8.4.6.5 in 2016, 14.2.6 in 2019-22, 14.2.5 in 2025)

Thanks in advance.

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6 Comments

Glenn Berger

8/22/2025 08:18:30 am

1) Since the facility is existing, you can get temperature readings to support (or disprove) your position.

2) 100 deg F at the roof level is a real potential depending on the ventilation system provided.

I would follow NFPA 13 with the exceptions allowed.

Anthony

8/22/2025 10:01:00 am

I agree with Glenn here. Also its August. Pick a hot day next week and see what the ceiling temp is. I'd expect something around ~110 later in the day. With that you're definitely justified for intermediate temp heads.

Brian M Gerdwagen FPE

8/22/2025 08:33:32 am

I have always put Intermediate Temperature sprinklers at warehouse ceilings. Most of the warehouses have been in SoCal and have recorded summer temperatures of 120F+. As for all the skylights, they may be combination skylight/smoke vents.

Dan Wilder

8/22/2025 08:42:22 am

That region has had several reoccurring heat waves yearly, with one recently in late June of this year (Boston hit +100°F). It would not be out of the question to install the intermediate temp ESFR sprinklers using that historical data.

8.3.2.1 (16' Ed.) & 9.4.2.1 (19' Ed) states "...ordinary AND intermediate...", 22' edition is revised slightly to state "OR". No where do these sections state the Ordinary is required specifically and with the amount of skylights, I'd imagine there will be a need for a higher temperature in locations so might as well make it easy for install with all the same temp.

NFPA 13-25' Section 16.4.1.1.1 uses a new method for determining freeze protection. I don't see why that same method should/could not be used to determine (and justify) sprinkler temperatures for the other end of the spectrum.

"The weather temperature used to determine if a portion of a system is subject to freezing and required to be protected in accordance with 16.4.1.1 shall be the average annual extreme minimum temperature, obtained from an approved source."

Also, as I am from the Southwest, it's rare that we ever put in ordinary temp sprinklers, unless required, for any system located at a roof. Heck, we use intermediate temp sprinklers in residential as a default to allow the lesser installation distances for diffusers. Those locations are also the exception but due to the HVAC installers not following coordination efforts, it saves a lot of arguments.

And no, it's very rare that I have seen any activations that could be attributed to a temperature mismatch. The ones we have been brought in on were mostly incorrect installation (crescent vs sprinkler wrench) or we could see damage to the sprinkler (frame or deflector). Some undetermined, but temperature was not a factor in those. The ones we have linked to a temperature were very obvious with a new unit heater or in the case of a loading dock with engine exhaust directly under the sprinkler.

Chad

8/22/2025 09:17:26 am

I’d have zero issue with all intermediate temps.

Some of the companies around here are doing that now and even light hazard office buildings so they don’t have to worry about them being too close to Hvac diffusers that can generate temperatures of 100 or more

Jack G

8/22/2025 09:32:50 am

As Dan points out, intermediate temp heads are allowed, and temps could spike in the warehouse you described.
I would be more concerned with pressure.
We use “ Texas trim kits “ ( relief valves) to protect the system. The graph that used to come when we ordered the kit from Reliable showed that a 3% air pocket. And a 10 degree rise in system temperature would more than double the pressure. They were for “ warehouses in Texas”.
I would check to see if the existing system had automatic air release valves. If not I would tell the client it would be a good idea to install them at the high points, and ( I do both ) at the system riser and intermediate temp heads.

Use Intermediate Temp Throughout Warehouse?

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