Field & trade terms
Firestopping
Firestopping is the material and detail that closes a hole in a fire-rated wall or floor back up after a trade has run something through it. A rated assembly only holds its rating if it stays continuous, and every penetration cuts a path for fire and smoke — firestopping is the sealant, wrap, collar or mortar that fills that path so the barrier performs as designed. It's tested as a whole system: the specific materials, the size of the opening and what passes through it all have to match a listed assembly.
Why it matters
A single unsealed penetration can defeat the fire separation an entire wall was built to provide. It's also one of the most commonly missed items, because the trade that made the hole often isn't the one responsible for sealing it, and the work gets buried behind finishes fast.
What an inspector looks at
The check is whether every penetration in a rated assembly is sealed with a firestop that matches a listed system for that condition — right material, right depth, annular space filled, nothing left open. Mixed penetrations and oversized openings get the closest look because they're the easiest to detail wrong.
RTI is photo-gated, so the proof is a close shot of each sealed penetration before it's covered, ideally showing the firestop material and the rated wall together. Once the ceiling or finish goes on, that photo is the record that the seal was ever there.
Checklists that put firestopping to work
Free, field-ready checklists, each with the photo every item needs before it can be submitted.
Related terms
- PenetrationAny point where a pipe, conduit, duct or cable passes through a wall, floor or roof — a hole that has to be sealed back to match the assembly it crosses.
- MEP (mechanical, electrical, plumbing)The mechanical, electrical and plumbing trades — the systems run through a building's structure that get inspected at rough-in and again at final.
- FlashingThin sheet material lapped into an assembly to direct water back out at joints, edges and openings before it can get behind the finish.
- Vapor barrierA sheet material that limits how much water vapor diffuses through an assembly, placed to keep condensation from forming inside the wall or floor.
- Air barrierA continuous plane of materials that stops air from leaking through the building enclosure, sealed at every joint, seam and penetration.
- Backflow preventionA device or assembly that keeps used or contaminated water from reversing back into the potable supply through a cross-connection.
Knowing the term is step one. Proving it is the job.
RTI holds the submit button until every mandatory item is answered and the photos are attached, then chains the record so it can be proven untouched later.