# Fire rated stair enclosure



## Kevin0616 (May 12, 2020)

For the fire rated stair enclosure in an noncombustible building (part 3 building in Ontario), can the wire (to the stove in the kitchen) penetrate the enclosure?

Thanks,


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## cda (May 12, 2020)

As in apartment building ??

Answer should be no.


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## Kevin0616 (May 12, 2020)

Thank you very much.  Yes, 4-storey and 8 unit apartment building.


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## steveray (May 13, 2020)

As much as I do not agree with it, outside membrane enclosure penetrations are more and more allowable....But no idea about Ontario...


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## tmurray (May 13, 2020)

Kevin0616 said:


> For the fire rated stair enclosure in an noncombustible building (part 3 building in Ontario), can the wire (to the stove in the kitchen) penetrate the enclosure?
> 
> Thanks,


Only things allowed in the enclosure are the things that serve the enclosure. Examples are sprinkler piping and wiring for emergency lighting and fire alarm systems. Note that the wiring penetration is permitted, but a penetration to support any wall mounted equipment is not.

If the enclosure is on an exterior wall, we have allowed some building service penetrations in a rated exterior wall because it is not really part of the exit enclosure from the perspective of this code requirement. 

This is challenging for areas that have kitchens and bathrooms sharing a wall with the exit enclosure. We typically see a false wall constructed on the suite side to support all the penetrations by building services.


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## Kevin0616 (May 13, 2020)

The enclosure is for the stair exit, built with steel stubs and drywall, not bearing.  Does it make more sense to add a furring wall on top of the enclosure to host the wiring?


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## Kevin0616 (May 13, 2020)

The enclosure is built with steel stubs, plus 2-layers of drywall for the outside and one layer of drywall for the inside. the furring wall will be on top of that.


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## tmurray (May 13, 2020)

That is the typical way we see it done.


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## Kevin0616 (May 13, 2020)

@tmurray   Thank you very much and I appreciate your help.


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## steveray (May 13, 2020)

IBC 1023.5

exit stairways and ramps.
Exception: Membrane penetrations shall be permitted on
the outside of the interior exit stairway and ramp. Such
penetrations shall be protected in accordance with Section
714.3.2.


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## Paul Sweet (May 14, 2020)

I don't know about Canada, but many building officials consider lining the stud cavity with an extra layer of 5/8" type X gypsum as creating a chase within the wall that protects the stair enclosure from the wire or pipe.


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