# Four Story R2 appartments and Dryer Vents



## Rays197 (Feb 4, 2016)

Shall dryers vents penetrating the fourth floor ceiling be wrapped or chased in the attic area in a new construction four story R2 apartment building with a common attic shared that is not sprinkled? I have read sections 607.6 thru 607.6.2 (2012 IMC)  and the referenced sections to the IBC 714 (2012 IBC).

Thanks


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## cda (Feb 4, 2016)

Welcome.....,

What state do you happen to be in?? Sometimes it helps answer the question


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## cda (Feb 4, 2016)

I want to say no

You only need to worry about any penetration through a rated wall


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## Rays197 (Feb 4, 2016)

Im in Virginia. Also there is nothing in the USBC (uniform statewide building code). The ceiling on the fourth floor is only 1-hour per the drawings.


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## rgrace (Feb 4, 2016)

Rays197, I assume that this building has a rated roof/ceiling assembly, based on the code sections you site. Is this correct? Are you referring to the dryer exhaust duct system for the 4th floor units only, or are you including the systems from the lower floors as well? Is the exhaust duct penetrating the top plate of a wall cavity within the unit or is it penetrating the ceiling membrane of the roof/ceiling assembly? You bring up a very tough question. These sections in the IMC and the IBC are not written well at all, and I have had to struggle with them as well. Just remember, this is not a partition penetration, so there is no exception permitted for fully ducted systems penetrating 1 hour partitions in fully sprinklered buildings


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## Rays197 (Feb 5, 2016)

> Rays197' date=' I assume that this building has a rated roof/ceiling assembly, based on the code sections you site. Is this correct? Are you referring to the dryer exhaust duct system for the 4th floor units only, or are you including the systems from the lower floors as well? Is the exhaust duct penetrating the top plate of a wall cavity within the unit or is it penetrating the ceiling membrane of the roof/ceiling assembly? You bring up a very tough question. These sections in the IMC and the IBC are not written well at all, and I have had to struggle with them as well. Just remember, this is not a partition penetration, so there is no exception permitted for fully ducted systems penetrating 1 hour partitions in fully sprinklered buildings   [/quote']The fourth floor ceiling is 1 hour rated. Each apartment is sprinkled but not the common attic. Yes, in reference to the dryer exhaust ducts are for the fourth floor only. The contractor is installing dryer vent boxes in the interior walls, up thru the top plate with nail plates and fire caulked. The dryer ducts are terminating up and out thru roof. Draft stopping every 3000 sq ft. in the common attic.


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## klarenbeek (Feb 5, 2016)

As long as the dryer vent stays in the wall assembly until it enters the attic, it is OK.  See IMC section 607.6.1, the exception and 607.6.2.1 exception #2.  They can do the same for bath fans if they mount them in the wall.


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## rgrace (Feb 5, 2016)

> As long as the dryer vent stays in the wall assembly until it enters the attic' date=' it is OK. See IMC section 607.6.1, the exception and 607.6.2.1 exception #2. They can do the same for bath fans if they mount them in the wall.[/quote']I concur with klarenbeek's response.


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## Rays197 (Feb 9, 2016)

I called ICC for an interpretation and was told no protection required for the dryer vent and this also applies to ducts for bath fans.

Thanks for all the input !!!


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