# Angled or 90 Transition 1-hour wall?



## Firerated (Dec 23, 2020)

We are building a new 1-hour rated wall from floor to deck, however directly above is a large sanitary Main pipe that essentially runs parallel to the new wall, the new wall must either (in section view) jog to the left 90 degrees and go straight up or be angled to avoid the pipe above ceiling then go straight up to deck. Is there any known standard for this situation, considering it has a 1-hour rating?


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## cda (Dec 23, 2020)

Welcome

You may have to wait till after Christmas, for answers

People are hitting the sleigh, to get out of the office.


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## cda (Dec 23, 2020)

So the pipe is above the rated wall??

Or if the wall was built to the deck,,, the pipe would penetrate it???


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## Firerated (Dec 23, 2020)

cda said:


> So the pipe is above the rated wall??
> 
> Or if the wall was built to the deck,,, the pipe would penetrate it???


So, essentially the pipes would run the length of the wall where is goes to deck directly above the wall, there is also a group of conduit that runs the length, its a pretty congested area. This wall is being built to align with another wall, so not many options to move it. Not sure if I explained that clear enough, but if you were to look at a wall section, above the acoustical ceiling the wall would need to jog to the left or right (90 degrees) about 10 inches, then go up to deck, to avoid the pipe running the length of where the wall would meet the deck.

Thanks!!


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## RLGA (Dec 23, 2020)

There is no general guidance in this area and GA-600 and UL do not provide any specifics about the use of the assemblies in regard to angled conditions.

In my opinion, I would say that as long as the slope is not greater than 30-degrees from the vertical, then it could be constructed consistent with the wall assembly requirements. If sloped more than that, then it might be considered a horizontal assembly and have to be constructed similar to a floor/ceiling assembly, which may only require an additional layer of gypsum board on the underside of the horizontal (or near horizontal) portion of the jog.


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## cda (Dec 23, 2020)

Great answer.

I am conceptually challenged,,  along with other challenges


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## Firerated (Dec 23, 2020)

RLGA said:


> There is no general guidance in this area and GA-600 and UL do not provide any specifics about the use of the assemblies in regard to angled conditions.
> 
> In my opinion, I would say that as long as the slope is not greater than 30-degrees from the vertical, then it could be constructed consistent with the wall assembly requirements. If sloped more than that, then it might be considered a horizontal assembly and have to be constructed similar to a floor/ceiling assembly, which may only require an additional layer of gypsum board on the underside of the horizontal (or near horizontal) portion of the jog.


Thanks. That was my thought as well, I reached out to UL as we typically use a U465 design for 1-hour rated and they didnt have any guidance, like you said. We have use the angled method on a smoke wall to avoid the ceiling issue in the past. Thanks for confirming! Do you know of any UL designs off hand for a floor/ceiling assembly 1 hour rated that might be close to what we are doing?


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## RLGA (Dec 23, 2020)

Firerated said:


> Thanks. That was my thought as well, I reached out to UL as we typically use a U465 design for 1-hour rated and they didnt have any guidance, like you said. We have use the angled method on a smoke wall to avoid the ceiling issue in the past. Thanks for confirming! Do you know of any UL designs off hand for a floor/ceiling assembly 1 hour rated that might be close to what we are doing?


I would look at UL L524 (requires 7-inch, 43-mil "joists") or GA-600 FC4503 (requires 6-inch, 54-mil "joists"). Both of these require plywood on the top, but you can add the gypsum board over the plywood.

Another option is UL I501, but this requires three layers of gypsum board on the underside of 6-inch, 33-mil studs. You can add a single layer on the top side so you do not create an area that collects trash, dust, etc.


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## Firerated (Dec 23, 2020)

RLGA said:


> I would look at UL L524 (requires 7-inch, 43-mil "joists") or GA-600 FC4503 (requires 6-inch, 54-mil "joists"). Both of these require plywood on the top, but you can add the gypsum board over the plywood.
> 
> Another option is UL I501, but this requires three layers of gypsum board on the underside of 6-inch, 33-mil studs. You can add a single layer on the top side so you do not create an area that collects trash, dust, etc.


This is great, thanks so much for the help.


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