jar546
CBO
A Type IA building has an interior exit stair located at a building corner. The exterior walls are non-rated curtain walls. Exposed HSS steel beams inside the curtain wall support the curtain wall and the intermediate stair landings but do not support any floors, the roof, or the 2-hour fire barriers forming the interior side stair enclosure.
It is my understanding that the beams are not required to have fireproofing per 2018 IBC Section 704.1, since the supporting beams are within the rated stair enclosure. (Again, these beams do not support floor landings). Can you confirm that the beams do not need to be protected?
ANSWER:
The walls enclosing the stairway are required to be rated, and the primary structural frame and floor construction need to be rated due to the type of construction, as detailed in 2018 IBC Table 601.
Section 1011.7 requires all stairways to be built of materials consistent with the types permitted for the type of construction of the building. While any structure supporting the stairway and the stairway enclosure must be fire-resistance rated consistent with the construction type, the stairway components inside the enclosure need only comply with the material limits for the type of construction and do not need a fire-resistance rating. In other words, intermediate landings are not regulated as floor construction and there is no requirement in the code that the intermediate landings of the stairways need to be rated. The exposed HSS steel beams do not need to be individually protected since they do not serve as primary or secondary frame members.
If there are beams attached directly to columns (posts) that support the stairway stringers and the floor, then the beams and columns are considered part of the primary structural frame as defined in Section 202 and shall have a fire-resistance rating based on the type of construction of the building.
If there are beams and columns that support only the intermediate stairway landings, then a fire-resistance rating would not be required for the landing or its supports.
It is my understanding that the beams are not required to have fireproofing per 2018 IBC Section 704.1, since the supporting beams are within the rated stair enclosure. (Again, these beams do not support floor landings). Can you confirm that the beams do not need to be protected?
ANSWER:
The walls enclosing the stairway are required to be rated, and the primary structural frame and floor construction need to be rated due to the type of construction, as detailed in 2018 IBC Table 601.
Section 1011.7 requires all stairways to be built of materials consistent with the types permitted for the type of construction of the building. While any structure supporting the stairway and the stairway enclosure must be fire-resistance rated consistent with the construction type, the stairway components inside the enclosure need only comply with the material limits for the type of construction and do not need a fire-resistance rating. In other words, intermediate landings are not regulated as floor construction and there is no requirement in the code that the intermediate landings of the stairways need to be rated. The exposed HSS steel beams do not need to be individually protected since they do not serve as primary or secondary frame members.
If there are beams attached directly to columns (posts) that support the stairway stringers and the floor, then the beams and columns are considered part of the primary structural frame as defined in Section 202 and shall have a fire-resistance rating based on the type of construction of the building.
If there are beams and columns that support only the intermediate stairway landings, then a fire-resistance rating would not be required for the landing or its supports.