Ever since I can remember there has always been a controversy about what product are suitable for "firestop" in various types of construction. I've always found that checking with the building department prior to installing the job worked best. Some would allow fiberglass insulation, some wanted duct seal and some wanted a Listed firestop product- even when the type of construction was combustible construction. What I find interesting is that the NEC at 334.80 (2005 Edition) recognize thermal insulation or sealing foam as products suitable for firestop or draftstop in wood construction. Am I reading this correctly?
