Firestop Required Within Unrated Exterior Wall Assembly

[chris_needs_help]

I have a multi-story, Type I-B building. The concrete on metal deck floor is rated, but the exterior wall is not. The metal framing for the exterior wall starts and stops at the floor. The wall assembly has a finish, but the main assembly has continuous sheathing on the exterior and gypsum board on the interior that also starts and stops at the floor. I am having a hard time determining if the edge of the slab need some sort of firestop or draftstop between the edge of slab and the backside of the continuous sheathing (within the wall assembly). Is there a specific code requirement for this?

 

[mtlogcabin]

705.9 Joints.
Joints made in or between exterior walls required by this section to have a fire-resistance rating shall comply with Section 715.

Exception: Joints in exterior walls that are permitted to have unprotected openings.

705.9.1 Voids.
The void created at the intersection of a floor/ceiling assembly and an exterior curtain wall assembly shall be protected in accordance with Section 715.4.

 

[chris_needs_help]

Thanks for the response. I had read these sections previously and thought that this meant "no" was the response to my original question. But I brought myself here because I was overridden by a much more senior person in my office.

 

[Sifu]

I think you would need a joint, if anything, but I don't think one is needed unless the exterior wall has a requirement for protected openings per t705.8. See 2018 IBC 715.1 #7.

 

[Sifu]

Sorry MT, didn't mean to mimic your post, I got delayed while writing mine and yours hadn't popped up.

 

[mtlogcabin]

715 pretty much refers to "curtain walls" and with out knowing how many stories and the type of wall it is hard to give a definitive yes or no answer to the question.

Welcome to the board. I like your screen name since that is why we all come here because no matter how long we are in this business we all need help from time to time.

I was overridden by a much more senior person in my office

Don't be intimated by a senior person. Codes change and some of us senior people just know it is in the code and when we go to look for what we know we cant find it or it is different than what we believe. Now that senior person is probably a wealth of knowledge that you can bounce code discussions off of so work on that relationship and remember not all codes are black and white and there is an intent behind everyone of them and that is the ultimate goal IMHO is to meet the intent of the code section.

"It doesn't say what you think it says, nor what you remember it to have said, nor what you where told that it says, and certainly not what you want it to say, and if by chance you are its author, it doesn't say what you intended it to say. Then what does it say? It says what it says. So if you want to know what it says, stop trying to remember what it says, and don't ask anyone else. Go back and read it, and pay attention as though you were reading it for the first time." Charles E. Beck, P.E. Seattle WA. 2006

Click on the link and go to post #37 and you will see an example of what I am saying about code changes

Is a permit required for a HABITABLE accessory structure

Just more reasons to stay far from left coast.

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