Water closets on upper floors and fire stopping

JH

The Corp of Engineers has decided that we have to firestop the core-drilled holes underneath the water closets. Has anyone had any experience with such a demand? Do you know of any codes or decisions about this?

JimGPE_3

Sounds right

There is almost always a code requirement for fire separation between floors of a building, and in that case, any penetration between floors must be fire stopped. In your case, this would probably consist of using fire caulk to seal the anular gap between the cored hole and the outside of the drain pipe. Its pretty easy.

It is perhaps true that you have never worked for an entity (code official or owner) that took this requirement so literally, but I think it is the spirit of the codes.

[Deleted User]

yup, some inspectors

are real sticklers for firestopping..can you wrap a rectorseal fire stop collar around the pipe? guess first i should ask what your pipe material is..you may just have to fill the gap with intumesant fire caulk.

Dave Yates (PAH)

If that's PVC piping

you can purchase fire-stop collars that fasten to the underside of the deck and will foam the opening shut in the event of a fire.

You could also build up the "throne" to install a fire-stop wye with a linkage that when melted drops a fireproof plug into the opening.(G)

We recently had to remove fire caulk from around metal ductwork where it penetrated a fire wall and the duct contained a fire damper. Some codes require that to ensure the duct can't be deformed by expanding caulk or drywall. I hates to point out the obvious, but an air gap around the ductwork creates the very chase and pathway we're trying to eliminate!

I've been in buildings where the fire was near installed PVC piping. In one I clearly remember, the PVC burned off and heat was obviously passed through to the restrooms above and on the other side of a fire wall. The lines showed obvious signs of heat stress and dipped rather dramatically between hangers. But, once the heat became intense enough in the adjacent room where the arsonist had started the fire that destroyed the store and warehouse, the PVC simply melted itself shut where it penetrated the block wall and the bathrooms on the other side actually fared much better than did the remainder of the building.

What if you hung a hammer next to the WC with a sign that says "In case of fire, break toilet tank and bowl. Let water run on floor to quench immediate area." (Just kidding.)

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JH

still looking

I have been searching the net since I first asked and I did find some mention in the Canadian code.
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(3) Combustible drain piping is permitted to penetrate a horizontal fire separation provided it leads directly from a non-combustible floor-mounted water closet through a concrete floor slab.
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It would seem to reason that a non-combustible pipe would deserve the same consideration and since the two countries codes are similar that it might be somewhere in the code here