Field & trade terms
Penetration
A penetration is anywhere a trade puts something through a building surface: a pipe through a slab, conduit through a rated wall, a duct through the roof, a cable through the enclosure. The hole itself is routine; the problem is that it interrupts whatever that surface was doing — carrying a fire rating, holding an air or water barrier, keeping out weather — and every penetration has to be sealed back so the assembly still performs.
Why it matters
Penetrations are where barriers fail, because the trade that makes the hole usually isn't thinking about the rating or the drainage plane it just cut. One open penetration can undo a fire separation, an air barrier or a waterproofing layer, and there can be dozens on a single surface.
What an inspector looks at
The check depends on what the surface does: a firestop matching a listed system through a rated assembly, a sealed boot or collar through the air or vapor plane, correct flashing where a penetration hits the weather barrier. The common thread is that the seal is complete and matches the condition, not just smeared on.
Because RTI closes items on a photo, each penetration is shot sealed and in context before it's covered — the seal and the assembly it protects in one frame, so there's a record after the wall or roof closes.
Checklists that put penetration to work
Free, field-ready checklists, each with the photo every item needs before it can be submitted.
Related terms
- FirestoppingSealing openings where pipe, conduit or cable pass through a fire-rated wall or floor so the assembly's rating is restored.
- FlashingThin sheet material lapped into an assembly to direct water back out at joints, edges and openings before it can get behind the finish.
- Air barrierA continuous plane of materials that stops air from leaking through the building enclosure, sealed at every joint, seam and penetration.
- 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.
- 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.
- 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.