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I am designing a fire sprinkler system for a 5-story residential apartment building.
The building is Type V wood truss construction with 16" open web wood trusses. The floor/ceiling assembly is a one-hour fire-resistance-rated construction (UL listed). Sheetrock is attached directly to the bottom of the joists with wood subfloor on top. The ceiling is inaccessible (concealed). The question of sprinkler above the ceiling has come up. I don't see a need for them. There is 6" sound batting above the ceiling. The Fire Marshal does not allow NFPA 13R design. It an NFPA 13 design. Is this space required to be protected? Any input would be helpful, thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe
11 Comments
Paul Pinigis
10/27/2022 08:11:33 am
What do you mean by "the Fire Marshal does not allow NFPA 13R"? Are you saying there is a local ordinance prohibiting 13R systems, or that 13R doesn't apply because it's a 5 story building?
Todd E Wyatt
10/27/2022 08:32:36 am
The Fire Marshal is correct in that this Group R-2 (Apartments) Occupancy Classification project is required to be protected by an automatic sprinkler system (ASPS) meeting NFPA 13 and not NFPA 13R since it is (5) stories. 2021 IBC 903.3.1.2 permits Group R buildings to be protected by a NFPA 13R ASPS if it is 4 stories or less.
Paul Pinigis
10/27/2022 08:24:43 am
Given that this is an NFPA 13 system, and these are combustible concealed spaces, you must meet one of the exceptions in 9.2.1 to omit sprinklers. Be careful applying this, because you have wood trusses, not joists or composite joists.
James Phifer
10/27/2022 09:00:48 am
I agree with everyone above. unless you fill that space with insulation, it appears you have a combustible concealed space that would require sprinkler protection.
Danefre
10/27/2022 09:16:10 am
You didn't mention if this is podium construction - 5 story is NFPA 13.
Jesse
10/27/2022 09:24:42 am
Sounds like the FM is right in requiring full 13 design. These are combustible concealed spaces. I'd consider having the GC fill these with non-combustible insulation.
schulman
10/27/2022 10:03:45 am
the insulation in the design was likely only specified for meeting the R-Value requirements ... energy code .. mechanical code. ... sounds like you have to inform them that they also have to meet the fire protection codes and do what all these smart people have suggested and fill the entire cavity with insulation.
Mike
10/27/2022 01:03:45 pm
Yes they are required
Alex
10/27/2022 03:36:34 pm
Hi,
Dan Wilder
10/28/2022 08:13:30 am
Here is a good chart to let you know what will be required for the 13 system along with the above info for allowable omission (with tradeoffs) and calc impacts as it goes much further than just the attic space.
John Gallagher
11/2/2022 10:43:27 am
Be sure to specify the correct sprinkler heads for the combustible concealed space, especially if you are using CPVC piping in that area. Leave a Reply. |
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