I have a flat exterior canopy that projects 10-feet from the building, constructed of 2x solid wood joists, ceiling attached directly to the underside, roof sheathing directly to the top.
There is no storage beneath the canopy; the area below would be considered light hazard.
I am having the architect change the sheathing attached directly to the underside from plywood to cement board, so I think I will meet the criteria to allow sprinklers to be omitted from beneath, per NFPA 13 Section 126.96.36.199 (2016 Edition), or Section 188.8.131.52 (2019 Edition), confirmed by the MeyerFire Canopy, Overhang, & Exterior Projection decision tree cheat sheet. (I realize I might have to take a closer look at the exposed material of the roofing.)
NFPA treats the area below, and the concealed space within the canopy separately. There are the combustible concealed space exceptions.
In my canopy, does the 4-foot width limit of 184.108.40.206.1.2 (2016), 220.127.116.11.2 (2019) mean I have to sprinkler the joists channels, or does the combustible concealed space omission of 18.104.22.168.5 (2016), 22.214.171.124(2019) overrule?
NFPA 13 126.96.36.199 (2019): Concealed spaces formed by ceilings attached directly to or within 6-inches of ... solid member construction shall not require sprinkler protection.
NFPA 13 188.8.131.52.1: Sprinklers shall be permitted to be omitted from within combustible... overhangs... that are constructed in accordance with 184.108.40.206.2 through 220.127.116.11.5.
NFPA 13 18.104.22.168.2 (2019): Combustible soffits, eaves, overhangs... shall not exceed 4-feet in width.
I’m thinking the section for sprinklering within canopies is more applicable to canopies with a larger void space within, that may not meet the usual combustible concealed space exceptions, where you’d have to make some minor modifications, no openings, and add draft-stopping to omit sprinklers from within the space.
The architect said on a canopy similar to this one, they had to fill the 2x joists channels with insulation, but I don’t where code would direct us to do this, unless they were TJI’s.
Does the 4-foot width limit specific to Exterior Soffits, Eaves & Overhangs overrule the Concealed Space Rules?
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