# Structural penetration of stair enclosure



## Vlab20 (Jul 29, 2015)

We are having an internal office disagreement regarding having a floor structure penetrate a stair enclosure. That structure is the floor system of the second floor and it penetrates the stair enclosure (steel studs and drywall) and forms the landing of the stair.

Building is a 2-story, E-occupancy, fully sprinklered, Type 2B construction. Code is Wisconsin IBC 2009. No areas of rescue assistance is required in the stair.

We have reviewed Section 707, 712, 713 and we can't seem to have a consensus.

Option 1: Some of the architects are saying we have to separate the stair enclosure completely from the adjacent floor assembly. The reason is that the floor joists outside of the stair could get super-heated and affect the stair landing structure inside the enclosure. This side is saying we either separate the structure or fire rate the entire floor assembly where ever it penetrates the stair enclosure.

Option 2: The other architects are saying we can penetrate the fire barrier walls with structure because the code does not say we can't and they argue that if the structure was required to be separated the code would have required that the walls be designed as "fire walls". Further they argue that because the building is a Type 2B the floor/ceiling assembly is not required to be rated.

Everyone understands that the rated stair enclosure is there to safely exit occupants and to do that in a roughly 60 minute time frame. It is understood that if a building is on fire that fire could affect egress paths and the structure thus the reason for two or more stairs from an upper level. It would seem that in a fire condition the floor system could fail and block the passage to a stair and the other egress paths would come into play. It would seem that a fully sprinklered Type 2B building has already factored in a level of safety and thus does not require the floors to be rated. Why would a landing inside the stair even with structure penetrating the enclosure and supporting the landing need to be rated when the floor right outside the stair is not required to be rated?

Your help would be appreciated.


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## cda (Jul 29, 2015)

????;;;

1022.4 Penetrations. Penetrations into and openings through an exit enclosure are prohibited except for required exit doors, equipment and ductwork necessary for independent ventilation or pressurization, sprinkler piping, standpipes, electrical raceway for fire department communication systems and electrical raceway serving the exit enclosure and terminating at a steel box not exceeding 16 square inches (0.010 m2). Such penetrations shall be protected in accordance with Section 713. There shall be no penetrations or communication openings, whether protected or not, between adjacent exit enclosures.

This section specifically lists the items that are allowed to penetrate a vertical exit enclosure. This is consistent for all types of exit enclosures, including stair or ramp vertical exit enclosures and exit passageways (see Section 1023.6). In general, only portions of the building service systems that serve the exit enclosure are allowed to penetrate the exit enclosure. As indicated in the commentary to Section 1020.1, standpipe systems are commonly located in the exit stair enclosures. If two exit enclosures are adjacent to one another, there must be no penetrations between them, thereby limiting the chances of smoke being in both stairwells. This requirement is not intended to prohibit windows in the exterior walls of stairways that are not required to be rated. This section and Section 1022.5 are meant to work together.


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## steveray (Jul 30, 2015)

I agree with those that say not allowed....But would need some more detail to really determine. That being said, if you could demonstrate that the enclosure was not penetrated and ran continuous "behind" the penetrant, you might have something. (FWIW I am having this discussion on a current project.)


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## mtlogcabin (Jul 30, 2015)

It depends on the floor system

2012 IBC

713.8 Penetrations.

Penetrations in a shaft enclosure shall be protected in accordance with Section 714 as required for fire barriers. Structural elements, such as beams or joists, where protected in accordance with Section 714 shall be permitted to penetrate a shaft enclosure.

714.3.1.2 Through-penetration firestop system.

Through penetrations shall be protected by an approved penetration firestop system installed as tested in accordance with ASTM E 814 or UL 1479, with a minimum positive pressure differential of 0.01 inch (2.49 Pa) of water and shall have an F rating of not less than the required fire-resistance rating of the wall penetrated.


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## steveray (Jul 30, 2015)

MT...I would argue that the specifics of 1022 (vertical exit enclosure)would take precedence over the general of 713 (shafts)....No?


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## mtlogcabin (Jul 30, 2015)

steveray said:
			
		

> MT...I would argue that the specifics of 1022 (vertical exit enclosure)would take precedence over the general of 713 (shafts)....No?


You might be correct. I will look at it more when I get back in the office later today


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## mtlogcabin (Jul 30, 2015)

steveray said:
			
		

> MT...I would argue that the specifics of 1022 (vertical exit enclosure)would take precedence over the general of 713 (shafts)....No?


You are correct. I failed to look at the charging language that I always instruct my guys to do

713.1 General.

The provisions of this section shall apply to shafts required to protect openings and penetrations through floor/ceiling and roof/ceiling assemblies. Exit access stairways and exit access ramps shall be protected in accordance with the applicable provisions of Section 1009. Interior exit stairways and interior exit ramps shall be protected in accordance with the requirements of Section 1022.



1022.5 Penetrations.

Penetrations into and openings through interior exit stairways and ramps are prohibited except for required exit doors, equipment and ductwork necessary for independent ventilation or pressurization, sprinkler piping, standpipes, electrical raceway for fire department communication 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.

714.3.1.2 would be applicable but 713 would not be applicable


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## north star (Jul 30, 2015)

*@ " @ " @*

***cda***  hit it out of the park on the first swing !

Way to go ***cda*** !      :mrgreen:



*@ " @ " @*


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## cda (Jul 30, 2015)

north star said:
			
		

> *@ " @ " @****cda***  hit it out of the park on the first swing !
> 
> Way to go ***cda*** !      :mrgreen:
> 
> ...


I get wood on the ball once in awhile


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## steveray (Jul 30, 2015)

The "penetrations into" is what gets everyone....That means (in theory at least) that you cannot enter the outside plane of the gypsum or block or whatever your rated assembly (fire barrier) might be....I end up sending schools with all of their cameras and security stuff to the State for modifications as they are not required by code and cannot be there by this section.


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## Vlab20 (Aug 3, 2015)

Thanks all, for your input. We are revising our thought process and will avoid the penetration of the shaft.


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