Fire Barrier wall’s bearing

[Examiner]

Given:

IBC 2006

Stair enclosure wall 1-hour rated.

Construction Type II-B

Upper Floor construction assembly: 30” deep structural steel open web joist w/ fluted metal floor deck filled with concrete and non-rated suspended ceiling system. Deck and concrete combined thickness 5-inches.

The floor assembly is not a rated assembly and therefore does not have the same fire rating as required for the Fire barrier.

Question:

If the stair’s rated walls bear on the floor above the opening and the stair’s rated walls below the opening are taken to the bottom of the floor deck or to the unprotected perimeter structural steel of the stair’s floor opening; does this comply with Sections 706.5, 707.5 & 717.2.2?

 

[Gene Boecker]

Re: Fire Barrier wall’s bearing

nope!

Structural continuity is not maintained since the loss of the floor system around the stair will mean the loss of the stair enclosure.

The typical response is to require the floor system for the structural by in which the stair is located to be rated the same as the stair enclosure. This assures that the stair should be still available - without cracking and compromise due to deflection of the floor system - for the same period as the stair enclosure.

 

[AegisFPE]

Re: Fire Barrier wall’s bearing

Not only the floor-ceiling assembly, but 1-hour protection could be required for protection of the structure supporting that portion of the floor as well, all the way down to grade per IBC 706.5.

 

[pyrguy]

Re: Fire Barrier wall’s bearing

Not only the floor-ceiling assembly, but 1-hour protection could be required for protection of the structure supporting that portion of the floor as well, all the way down to grade per IBC 706.5.

Rated walls require a matching rated structure supporting it all the way to the foundation.

Careful about grade, It can be above the foundation.