Firestopping
CSI Division 07, Thermal & Moisture Protection
Fire-rated sealants, caulks, and specialty devices installed at every penetration through a fire-rated wall or floor, pipes, conduit, cable trays, ductwork, to restore that assembly's fire rating at the point it's been penetrated, since even a small unsealed gap can let fire and smoke spread through an otherwise fire-rated barrier.
Why it matters
A fire-rated wall is only as good as its weakest penetration, and firestopping has to be installed using a system specifically tested and listed for that exact combination of penetrating item and wall type, an approach that works for a steel pipe doesn't automatically work for a bundle of plastic conduit.
On a real project
An electrician's conduit penetrations through a two-hour fire-rated wall are sealed with a firestop sealant system specifically tested and listed for that wall assembly and conduit type, referenced by a UL system number noted on the installer's documentation.
Who this matters most to
An Electrician or specialty firestop installer seals penetrations as trades finish their rough-in. A QA/QC Inspector verifies firestopping is installed correctly before the wall is closed in, since it's essentially impossible to inspect once finishes cover it.
Where this goes wrong
A general contractor's punch list catches several conduit penetrations through a fire-rated corridor wall that were never firestopped at all, the trade assumed someone else's scope covered it. The gaps aren't discovered until a life-safety inspection specifically probes penetrations behind the finished wall, requiring the wall to be opened back up to correct it.