David Bolton Fire-Rated Perimeter Weatherstrip on Steel Doors: Why the UL10C Listing Gets Overlooked Until the Door Fails Inspection Why Perimeter Weatherstrip Fails the Fire Door Inspection — and Nobody Noticed Until the End This article is for commercial contractors, facility managers, and project architects who are specifying or... NFPA 80 UL10C fire-rated doors perimeter seals weatherstrip May 25, 2026