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acb324 (Mechanical) (OP)
15 Aug 12 11:49
When are sprinklers required under an overhang on a building per NFPA 13? My confusion is caused by the annex in this instance.

NFPA 13 (2010) 8.15.7.2 states that sprinklers can be omitted from beneath projections that are non-combustible. Period. Nothing about the occupancy above the overhang is mentioned.

However, the corresponding annex material A8.15.7.2 states that areas under exterior ceilings where the building is sprinklered should be protected due to the occupancy above. Is there a reference in the actual document (as opposed to the annex) that bolsters this? Each time I provide sprinkler coverage under these circumstances I am asked to defend it and would like to know if there is something better than the annex to support it.

I have a building that looks like an inverted tiered cake, with the second floor larger than the first, causing an exterior overhang exceeding 4'. In my opinion this should have sprinkler coverage due to the sprinklered occupancy above. Can anyone clarify?
cdafd (Specifier/Regulator)
15 Aug 12 12:36
The canopy/ four foot rule keeps changing depending on the edtion you use.

If non combustible than sprinklers are not required, unless storing combustibles under them.

With your secnario, yes there is a non combustible overhang above say the first floor, and the rest of the building is sprinkled, so hopefully if the fire were to start inside the building on the second floor. The system would work and keep it confined to inside the building.

Read the annex and I think that as long as the non com or limited com is met,even though there is an overhang above, you are not required sprinkler protection, unless once again there is combustible storage.
Pyrophoric (Mechanical)
15 Aug 12 12:46
The overhang and canopy language refer to a typical condition where there is no occupied space above the canopy. I would believe that any AHJ and sound engineering practice would dictate that you sprinkle the underside to protect the integriy of the supporting structure above.

Fire Protection Engineers give Firefighters sloppy seconds.

cdafd (Specifier/Regulator)
15 Aug 12 12:57
Pyro
What section of 13 would require it???
Pyrophoric (Mechanical)
15 Aug 12 13:56
I think the confusion is in the terminology. "Exterior Roofs, Canopies, Porte-Cocheres, Balconies, Decks, or similar projections" - That implies at worst, minimum occupancy above (deck or balcony), but not an entire section of the floor above. I treat this similar to the mezzanine rules where the occupant load is comparitively low. The bigger reason for putting sprinklers in every layer of cake is the possibility of flame lapping out of a window from an occupied floor onto the bottom of the floor below, or if possible, increasing the fire rating on the higher floors and sprinkler the ground floor where cars and the occasional UPS truck may congregate.

The short answer, I guess, is no. There is no direct verbiage that I can think of in teh sprinkler code to require sprinklers under any type of overhang that is non-combustible in construction and exposed surface. But there are many reasons why it's a sound idea.

Fire Protection Engineers give Firefighters sloppy seconds.

acb324 (Mechanical) (OP)
15 Aug 12 14:41
Thank you for your replies. I am glad to know that I did not overlook anything, and also that I am not the only one who thinks it is a good idea to sprinkler something like this. I hope more people reply with what they typically do under these circumstances.

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