Will you please clarify why a Building Area Increase is NOT permitted for an NFPA 13R design?
We are working on a project and the architect has stated that the calculations following IBC T506.2 allow for an area increase up to 135,000 sf. We are working in IBC 2015. The Owner would like confirmation that the 4 story R-2 Type V-A building can be protected under NFPA 13R when it is over 12,000 sf. Posted anonymously for discussion. Discuss This | Submit Your Question | Subscribe
8 Comments
Wes
1/13/2020 07:18:34 am
There is no credit for an NFPA 13R system versus no system at all for an R-2 occupancy. If you check the Table 506.2 for R-2 Occupancy (IBC 2015), all of the tabular allowable building areas are the same for "NFPA 13R system (S13R)" and "No System (NS)".
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1/13/2020 10:48:07 am
Building area increases are attributed to NFPA 13 because sprinklers are installed in occupied and non-occupied spaces at a density (0.10 gpm/sf min.) proven for fire control and property protection.
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Marc Vieno
1/13/2020 11:21:01 am
That area calc is pretty wild, are you sure it's 135,000 sf and that's not a typo? 5A construction allows for 12,000 sf with 13R, 48,000 sf with a full 13 system.
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Brian Gerdwagen FPE
1/13/2020 05:34:04 pm
There is no area increase allowed for a 13R system for two reasons, the first is as Wes said, it isn't a full coverage system. The second is that the IBC since 2009 requires a sprinkler system in all R occupancies, so the area shown already expects to have a 13R system as a minimum.
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Jean Martin
1/14/2020 10:32:34 am
Please pardon my ignorance. I still don't see a code reference that definitively states that for NFPA 13R an area increase is not allowed in this case..
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Wes
1/14/2020 10:58:54 am
You're right - you can use Equation 5-2. Just follow those steps and you'll get to the same conclusion that an NFPA 13R system doesn't benefit the allowable building area for this project.
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Brian Gerdwagen FPE
1/14/2020 04:02:32 pm
In older IBC editions they were very hidden and difficult to decipher. For example, in the 2012 edition, Section 504 allows a height increase of 20' was given for systems complying with 903.3.1.1 and an increase of 20' up to 60' with a maximum of four stories for a 903.3.1.2 system. You need to read the Chapter 9 section to see that 903.3.1.1 is a 13 system and a 903.3.1.2 is a 13R system.
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Jean Martin
1/14/2020 05:34:41 pm
I think the confusion revolves around the exact definition of the verbiage, "area increase."
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