Draftstop Req'd In Omitted Concealed Spaces?

12/9/2019

We have a residential R-2 occupancy, four-story, combustible Type V-B, new construction building with an NFPA 13 system. The floor/ceiling assemblies are built with open-web wood trusses.

All of the interstitial spaces around these trusses are to be filled with non-combustible insulation, which allows sprinklers to be omitted within them in accordance with NFPA 13-2013 8.15.1.2.7 "concealed spaces filled with noncombustible insulation shall not require sprinkler protection."

The IBC (2015) requires drafstopping in combustible construction to "subdivide floor ceiling assemblies" above an in-line with dwelling unit and sleeping unit separations (IBC 2015 718.3.2). However, an exception exists for buildings equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1 (an NFPA 13 system).

If these spaces omit sprinklers due to non-combustible insulation, is draftstopping still required per the IBC?

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2 Comments

sean

12/9/2019 08:21:33 pm

The issue becomes NFPA 13 vs 13R.

The code IBC says you need to have a sprinkler system per NFPA 13 to omit the draft stopping you can then utilize the exception in NFPA 13 for "filled with insulation". Note that filled with insulation may not meet the STC sound rating design. SO NFPA 13 with an exception is ok.

But note per NFPA 13R it specifically says it must have heads and NFPA 13R does not have specific language for that exception.

Felicia Blake

7/2/2024 02:49:11 pm

I am having the same question for a similar hotel. Did you find an answer to your questions?

Draftstop Req'd In Omitted Concealed Spaces?

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