Fireblocking question w/ pics

NEW-B

I've read through the entire "How to Fireblock" thread but am still kind of unsure if anything more needs to be done for these scenarios.

1) The waste pipe is about 4" off the wall. We will be attaching 2x2s to the top plate extending out from the wall about 6" and then up to the ceiling attached to a 2x4 running perpendicular to the trusses, thus creating the soffit. Besides blocking it off where it will intersect with the connecting walls, I don't see where else it would need to be blocked. Is this all that needs to be done with this area?





2) Where my walls a parallel to the studs, there is only at most a 1/2" gap between the top plate and the xps. I assume this gap just needs to be filled with caulk or foam and thats all for these walls.



3) Where walls are perpendicular, I assume the same is true. As long the small 1/2" gap is filled, there is no way anything can escape from each cavity.



It seems simple enough but the more I read on fireblocking, the more my mind tries to over complicate it.

Gary in WA

You need to stop a fire inside the wall from reaching the floor spaces above (cavities). 3/4" plywood or solid wood from the foam out to the soffit vertical sidewall, nailed to the bottom of the floor trusses. Also need it every 10' horizontally, from floor to ceiling (vertically); http://www.codecheck.com/cc/images/CC5thEdSample.pdf
Check locally with B.D. if they accept foam board continuous on concrete. I've had to cap running wall top plates with plywood that are parallel to truss above.

Gary

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NEW-B

So basically i'll have to cut notches out for those pipe hangers and either foam the gaps or put some more plywood perpedicular to cover them.

We use the 2006 International Building Code, however, I'm not getting inspections or pulling a permit. My assumption was that all the XPS should be covered with either drywall or plywood, even the XPS between the top plate and the sill. Would it be in my best interest to just remove any XPS that goes beyond the top plate and then just caulk or foam the gap between the concrete wall and top plate, thereby encapsulating the XPS?

Rory Read

NEW-B,

I use a fair bit of Rock Wool / Mineral Wool to fire block voids in basement walls and joist bays.

5/8" drywall can also be used, and wall board guys are very, very good at notching around things (although I know I do need to pay close attention to their work in that sort of situation).

Looks nice,

Rory

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Rory

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Portland, OR

NEW-B

After doing more research, I do not believe the soffit needs to be blocked from above. The stud wall stops below that pipe and will be blocked all along that wall. So nothing in the stud cavities can travel into the soffit. That pipe is essentially part of the ceiling above. Does that make sense?

EDIT: this pic helps illustrate what I'm trying to say