# Run items (ducts, conduits, pipes, etc.) in rated stair wall



## Adrienne (Jul 17, 2018)

I know that per 1023.5 of the code, there are no penetrations allowed in an interior exit stairway except for the items listed that serve the stair. Per the exception though, membrane penetrations are allowed on the outside of the enclosure. Are you then allowed to run items inside the wall that are not serving the stair? For instance a line-set serving a room located below the rated stair?


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## Paul Sweet (Jul 17, 2018)

Some building officials consider lining a stud cavity with a second layer of Type X gypsum board as creating a chase that is outside the enclosure wall.


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## RLGA (Jul 18, 2018)

There isn't any restriction of what can be inside a fire-resistance-rated assembly in regard to plumbing, electrical, or mechanical--there is just restrictions on how those items enter and exit (i.e., penetrate) the assembly.


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## Paul Sweet (Jul 18, 2018)

A lot of building officials consider anything inside the wall enclosing a stair as not being outside the stair enclosure.  This is because the fire-rated enclosure wall is an assembly and anything within the assembly is not fully separated from the enclosure.


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## RLGA (Jul 18, 2018)

Paul Sweet said:


> A lot of building officials consider anything inside the wall enclosing a stair as not being outside the stair enclosure.  This is because the fire-rated enclosure wall is an assembly and anything within the assembly is not fully separated from the enclosure.


That may be so, but Section 1023.2 (2018 IBC) states that enclosures of stairways and ramps are to be constructed as fire barriers and horizontal assemblies, and neither of those respective sections prohibit MEP elements within the assemblies. Section 1023 only restricts what can penetrate the enclosure.


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## steveray (Jul 18, 2018)

We get a little picky with it....

(Amd) 1023.5 Penetrations. Penetrations into or through interior exit stairways and ramps are
prohibited except for equipment and ductwork necessary for independent ventilation or
pressurization, sprinkler piping, standpipes, electrical raceway for fire department communication
and security systems and electrical raceway serving the interior exit stairway and ramp and
terminating at a steel box not exceeding 16 square inches (0.010 m²). Such penetrations shall be
protected in accordance with Section 714. There shall be no penetrations or communicating
openings, whether protected or not, between adjacent interior 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.

(Amd) 1024.6 Penetrations. Penetrations into or through an exit passageway are prohibited
except for equipment and ductwork necessary for independent ventilation or pressurization,
sprinkler piping, standpipes, electrical raceway for fire department communication and security
systems and electrical raceway serving the exit passageway and terminating at a steel box not
exceeding 16 square inches (0.010 m²). Such penetrations shall be protected in accordance with
Section 714. There shall be no penetrations or communicating openings, whether protected or
not, between adjacent exit passageways.
Exception: Membrane penetrations shall be permitted on the outside of the exit passageway.
Such penetrations shall be protected in accordance with Section 714.3.2.


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## Adrienne (Jul 18, 2018)

Wouldn't running an MEP element inside the wall be considered a membrane penetration? It is not a penetration into or through the stair.


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## Francis Vineyard (Jul 18, 2018)

Adrienne said:


> Wouldn't running an MEP element inside the wall be considered a membrane penetration? It is not a penetration into or through the stair.


Yes, see RLGA response (post #5).


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## RLGA (Jul 18, 2018)

Adrienne said:


> Wouldn't running an MEP element inside the wall be considered a membrane penetration? It is not a penetration into or through the stair.


If the MEP elements run within the wall and do not penetrate either the stairway-side gypsum board or the room-side gypsum board, then there are no penetrations at all--no harm, no foul. If an MEP element penetrates the stairway-side of the gypsum board, or both the room-side and stairway-side gypsum board, then it must be a MEP element that serves the stairway and is limited to those items in Section 1023.5 (2018 IBC). If it penetrates the room-side gypsum board, then it is a membrane penetration that is subject to the exception in Section 1023.5. All penetrations must be treated per Section 714 (2018 IBC).


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## Adrienne (Jul 18, 2018)

Thank you everyone!


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