BCAB #1677 - Smoke Control, Sentence 188.8.131.52.(4)
October 21, 2010
Re: Smoke Control, Sentence 184.108.40.206.(4)
The project consists of three residential hi-rise towers on a common four level parkade with ground floor retail. The parkade has three levels above grade and one below making the fourth storey the first residential floor. The exit storey is the ground floor/first storey. Vestibules are provided between the elevator shaft and the adjacent floor areas.
Reason for Appeal
Sentence 220.127.116.11.(4) requires measures be taken to limit smoke movement from floor areas below the lowest exit level into upper storeys. Appendix note B-18.104.22.168.(4) provides guidance on mitigating smoke movement through elevator shafts and vertical service spaces. B-22.214.171.124.(4)(1) suggests that a vestibule serving an elevator shaft that serves upper storeys and penetrates the floor of the storey below the lowest exit level needs to have a fire resistance rating.
The appellant contends that the project in question has only one storey (basement parking) below the lowest exit level (ground floor) so the elevator shaft does not penetrate the floor of the storey immediately below the lowest exit storey. Therefore, a fire rated vestibule is not necessary between the elevator shaft and the remainder of the floor area.
Building Official's Position
The building official maintains that the Appendix wording is not clear and can be interpreted to mean that if an elevator penetrates storeys (floors) both above and below the lowest exit level then fire rated vestibules are required between the elevator and the below grade storeys.
Appeal Board Decision #1677
It is the determination of the Board that a fire resistance rating is not required for vestibules between the floor area and an elevator shaft where the elevator shaft serves only one storey below the lowest exit level.
George Humphrey, Chair