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.
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.
