2-Story, 2B (could be any Type I or II)
Section 603 clearly identifies where combustible material is allowed in Type I & II construction. My question pertains to "blocking" and when does a certain of amount of "blocking" become sufficient to justify fire-retardant material.
Often we use 3/4" plywood on the back side of a parapet framed with metal studs to allow attachment of flashing/roofing. The plywood serves both as the wall cladding and blocking. The parapet could range in height from 2' to say 8'-10'. At some point it seems suitable to use fire-retardant since this becomes more of a wall then just blocking. On taller walls (above 4') we have used non-fire-retardant plywood on the lower 18" and then gypsum board above.
Just curious of what others are seeing/doing. I have not had a jurisdiction say one way or another. My gut tells me there is so little fuel (since only cladding might be combustible) in the "big" picture that is probably does not matter, but also technically might not comply with code language.