Use Sidewalls in a Room With Sloped Ceilings?

10/2/2024

Is there any way to install sidewall sprinklers in a room with sloped ceilings?

Say you had a rectangular room with a ceiling attached directly to the underside of a traditional gable roof with a high ridge peak in the middle. Concealed pendent ceiling sprinklers are often not possible because the space above the ceiling is completely filled with insulation.

Can you do sidewalls on the vertical walls near the ceiling high point to protect the room?

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8 Comments

Pete H

10/2/2024 06:42:32 am

https://www.meyerfire.com/blog/dont-let-the-slope-fool-you

There was an old blog post on the subject here, it has valuable information like:

"Sidewall sprinklers are required to have the deflector aligned parallel to ceiling or roof slopes (NFPA 13 2002-2016 Editions Section 8.7.4.2), and, where the slope exceeds 2 in 12 the sprinkler must be located at the high point of the slope and be positioned downward (NFPA 13 2002-2016 Editions Section 8.7.4.2.2). Additionally, as with all slopes, the sprinkler coverage is measured along-the-slope, not in floor area (NFPA 13 2002-2016 Editions Section 8.7.3.1.2)."

--

Mind you, they have to be listed to be more than 6" below the ceiling, and they can't be less than 4" below the ceiling.

Jesse

10/2/2024 08:16:47 am

Agree with Pete here. In slopes of 2:12 or greater, the deflecter has to match the slope.

In my opinion, horizontal sidewall sprinklers are the most misused sprinkler out there. Their listing is very narrow, Of particular note; they're listed for use under a smooth flat ceiling - or in other cases like under a raised OH door. I see a lot of designers try to get away with using them in open-to-deck situations that do not have smooth, flat ceiling.

Will the sprinkler work? Yeah, probably work just fine. But its all in the listing.

James Art, FPE

10/2/2024 05:58:31 pm

Sidewalls can be very slow.

Years ago, there was a burn building in Colma, CA
where the FD was seeing for themselves how residential fire sprinklers worked,
esp with a domestic meter supplied by a fire hose from the fire hydt.

I was invited to observe and comment.
So for one test we used an standard upright sprinkler in the middle of the room,with a fire in the far corner.

I suggested we "install" a residential sidewall, and a standard sidewall, just stuck into the plaster on the other side, no pipe, so we could see when they "activated". The upright was slow, but the sidewalls never did.

Anthony

10/2/2024 08:24:47 am

Yes you can use sidewalls at the peak of a traditional double slope ceiling but you'll need a baffle or lintel.

NFPA 13-16:

8.7.3.1.4 Sidewall spray sprinklers shall not be installed back-to-back without being separated by a continuous lintel or soffit.

8.7.3.1.4.1 The maximum width of the lintel or soffit shall not exceed 16 in. (400 mm).

8.7.3.1.4.2 The maximum width of the lintel or soffit can exceed 16 in. (400 mm) when a pendent sprinkler is installed under the lintel or soffit.

I've seen sidewalls at the base of a sloped or barrel ceiling out in the wild SOOOO many times. It drives me crazy.

Ray J link

10/2/2024 08:26:23 am

We have used a double 90 on a sprig to get the correct angle with the ceiling.

Jay

10/2/2024 09:12:51 am

If you are installing residential sprinklers, see the manufacturer's residential design and installation manuals (reliable, viking, etc). The hsw sprinklers are listed for many more applications under sloped ceilings than shown in the standards (13, 13D, 13R).

Jack G

10/2/2024 10:38:42 am

Agree, but I’ve run them at the high point peak like an attic sprinkler, ( but reg sidewalls 6 inches from each other in a back to back scenario) angled them with slope ( short nipples ) then enclosed them in a minimal soffit( width) , depth to accomodate the listing.

Glenn Berger

10/2/2024 01:06:23 pm

Great responses made above. Need to have dimensions / section cut of the space to provide a conclusive response.

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Use Sidewalls in a Room With Sloped Ceilings?

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