I have a building (cold storage facility)that I'm providing fire protection to that is constructed of 38" deep Red L web trusses. Plywood is attached to the bottom of those trusses. This creates a combustible concealed space 38" deep. 12" of R38 insulation rests on the plywood. I am installing a dry sprinkler system with upright sprinklers below the plywood to protect the storage below, and using 1" sprig ups with upright sprinklers into the combustible concealed space. My question is this...what do I have to do to the penetration in the plywood? IBC 2009 Edition is the applicable building code, NFPA 2007 Edition is the applicable sprinkler standard. I would think placing an escutcheon plate over the annular space would be satisfactory from a fire protection standpoint. It's not a fire-resistant-rated assembly. However, 713.4.2 addresses Nonfire-resistance-rated assemblies and under 713.4.2.1 Noncombustible penetrating items (which fire sprinkler piping is) states "...that the annular space is filled to resist the free passage of flame and the products of combustion with an approved noncombustible material or with a fill, void or cavity material that is tested and classified for use in through-penetration firestop systems." Since the plywood isn't fire-resistance-rated, why would I need to use a noncombustible material to fill the annular space?

Also, in 713.4.1 Fire-resistance-rated assemblies under 713.4.1.2 Membrane Penetrations Exception 5 states "The annular space created by the penetration of a fire sprinkler, provided it is covered by a metal eschutcheon plate." So if it's a fire-resistance-rated assembly that is penetrated, if it's for a fire sprinkler, a metal eschutcheon plate is satisfactory. It doesn't say anything about that under the Nonfire-resistance-rated assembly section.

Any thoughts?