OK to "Tent" a Wet Sprinkler System in 0°F Attic?

4/1/2024

Is "tenting" wet system piping (in an unheated attic) an appropriate approach to protect the pipes when the outside air temperature can drop to approximately 0 degrees F for multiple consecutive days?

In this case, the soffit and ridge vents allow exterior air into the attic space and there is no air barrier to prevent cold air infiltration. I have reviewed NFPA 13 and 13R and cannot find a definitive answer.

Many thanks for assisting.

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13 Comments

Anthony

4/1/2024 07:54:13 am

It's appropriate if you have sufficient insulation above and heating bleed through form below.

I'd add keep the pipes away from the edges of the building and make sure you have at least R30 above the piping.

Dan Wilder

4/1/2024 08:09:13 am

The installation is to be in warm areas, not subject to freezing, or provide means to avoid freezing (antifreeze, tenting, dry system, heat trace, circulating, heat loss calculation) is defined within 16.4.1 (19' Ed). It's up to the installer to comply with the warm space installation as required per NFPA.

Tenting, within NFPA 13, just pushes over to 13D and the figures within A.9.1.1 as with the other reference 8.2.3.1.1 (19' Ed.) so both are more directed to a residential application but not specifically "not allowed" or "allowed", it's just an option.

If at all possible, keep the piping as far away from the exterior as available for the install, install the piping as close to the ceiling, and avoid wrapping the piping with insulation (hence the "tenting" method to allow the lower warm air to directly impact the piping) which can be difficult with the blown in insulation that is more being used (at least in my area) vs the rolled, (cellulose vs fiberglass). However, based on the short description and temps, this would not likely be an installation path my company would allow without some very specific language and details in the contract and plans.

See below as well:
https://nfsa.org/wp-content/uploads/2021/02/Insulation-White-Paper-final-2.pdf

RayJ

4/1/2024 08:18:09 am

Here in IL, or as I call it, the land of ice and snow, the best way to protect the pipes is a dry system. No matter how much tenting and insulation you have, all it takes is for someone to forget to replace the insulation.

4/1/2024 08:35:43 am

ND = Frozen Tundra. I would say any area where temps drop below 30 degrees for consecutive days (especially where wind flows through the attic) a dry system is the only way to go. Tenting is a joke because the insulation required never stays put. IMO

Glenn Berger

4/1/2024 09:28:09 am

Tenting sounds like a good engineering approach until the first time the system freezes and then breaks. Once this happens, then the approach of never again will be utilized.

Jesse

4/1/2024 09:53:16 am

It is appropriate, but I'd probably want to see a heat-loss to support it.

Jack G

4/1/2024 10:14:04 am

First rule of Fire Protection- wet systems :
1.0 Insulation does not create heat !

Pete H

4/1/2024 12:50:00 pm

In NFPA 13R (2016 edition)

Check out figure A.5.4.2(f) Insulation Recommendations - Arrangement 6.

It'll be a claim you can make in 13R, but antifreeze or heaters would still be better.

4/1/2024 01:13:04 pm

Correct me if I'm wrong, but I believe this is only for an area above the ceiling and 'not' in the attic space. Insulation over piping in the attic space will not stop the water in the pipe from freezing in North Dakota, so I imagine it is the same in any place above the freeze line? I think there may need to be a separation between the two areas, pipe in the joist vs attic space. Maybe separated by sheet rock or plywood?

Pete H

4/1/2024 01:40:34 pm

The exact ruling is that piping covered by insulation as shown in those diagrams is part of the area below the ceiling and not part of the unheated attic area.

Except, it is literally above the ceiling, the insulation just makes it considered as part of the heated space below the ceiling as per A.5.4.2 of 13R (2016), even though, as seen in all of the figures, the head goes from the unheated space into the heated space. (Assuming the AHJ agrees that the Annex is acceptable code.)

Was this just to have pipe in the attic to protect the upper floor or was this to protect the attic?

If you're just protecting the upper floor, it's pipe that is literally in the attic, but is not considered in the unheated space due to the insulation method as per the figures.

If you're trying to protect the attic itself, you're correct, this will not work.

If you're in 13R, you might be able to omit protection in the attic as per section 6.6.6 (13R 2016) "Sprinklers shall not be required in attics, penthouse equipment rooms, elevator machine rooms, concealed spaces dedicated exclusively to and containing only dwelling ventilation equipment, crawl spaces, floor/ceiling spaces, elevator shafts where the elevator installation complies with ANSI 17.1 and other concealed spaces that are not intended for living purposes or storage and do not contain fuel-fired equipment.

If you're in 13, and it's a wood attic, you gotta protect that, no omission, and yeah, this pipe either needs to be a dry system, an antifreeze system, or heat traced.

I don't know whether this is in 13 or 13R, both were referenced.

Pete H

4/1/2024 01:42:09 pm

For reference, the area above the blown in insulation on A.5.4.2(f) is labelled "unheated attic space"

4/1/2024 01:55:59 pm

Thank you Pete.

Dewayne Martinez

4/2/2024 12:54:11 pm

In the past on 13R projects we have had the GC make a "box out" of the pipe with the blue polystyrene insulation board, add some grill registers in the ceiling below to transmit some heat and then have the insulation contractor provide what they felt was enough insulation on top to maintain 40F.

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OK to "Tent" a Wet Sprinkler System in 0°F Attic?

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