Plumbing Chase vs. Shaft
by Brad Keyes, CHSP, on Feb 27, 2019 12:00:26 AM
Q: What are the code requirements for penetrations in plumbing chases? During the water fountain project we found openings in the floor in the back of the plumbing chases from the original construction in 1949. Pluming lines pass through these openings. Is it required that these penetrations be fire stopped.
A: It depends…Were you looking at chases or shafts? A ‘pipe chase’ is where pipes run vertically from one story to another story, internally to the building, and the deck between the two stories is sealed over and meets the requirements for fire-rated construction for the horizontal barrier (i.e. floor). The vertical pipes penetrating the horizontal deck are sealed with proper fire-stopping materials. If the pipe chase has any vertical walls to protect the pipes, they are not required to be fire-rated and any pipe penetrations though these non-rated chase walls are not required to be fire-stopped.
A ‘mechanical shaft’ may look similar to a chase, but the horizontal deck between the stories is open and there is no attempt to seal the opening between the two stories. This means the vertical shaft walls must be fire-rated and any penetrations through these fire-rated shaft walls must be properly fire-stopped. Also, any HVAC duct penetration through a vertical shaft wall must have a fire damper at the shaft wall opening, regardless of the fire-resistance construction of the shaft walls.
So, you say you found openings in the floor, and since you could see them, that implies there were no vertical fire-rated walls concealing the shaft. So, it sounds like you have a serious breach of the horizontal barrier (i.e. floor) that needs to be repaired back to the original intention of the building. If these are small holes, then proper fire-stopping materials would likely be acceptable. If these are large holes, you may have to reconstruct the floor in that area as fire-stopping materials are only valid for a certain size opening.