BCAB #1547 - Openings Near Unenclosed Exit Stairs, Sentence 22.214.171.124.(1) and 126.96.36.199.(1)
August 15, 2001
Re: Openings Near Unenclosed Exit Stairs, Sentence 188.8.131.52.(1) and 184.108.40.206.(1)
Two townhouse units share an exterior passageway that is the only means of egress from each suite. Near the end of the passageway, the exterior wall(s) turns 90 degrees with window openings approximately 450 mm from the corner. Exit stairs are incorporated in the path of travel beyond the end of the passageway as indicated in sketch SK-4, or there are stairs within the passageway as indicated in sketch SK-4a.
Reason for Appeal
Sentence 220.127.116.11.(1) requires that where an unenclosed exit stair or ramp provides the only means of egress from a suite, and is exposed to fire from openings in the exterior wall of another fire compartment, the openings shall be protected when they are within 3 meters horizontally and less than 10 meters below or less than 5 meters above the exit stair or ramp.
Sentence 18.104.22.168.(1) requires openings in exterior walls adjacent to an exit be protected with wired glass or glass block if the openings are within 3 meters horizontally and are located in an exterior wall that intersects a wall of the exit enclosure at an angle less than 135 degrees.
The appellant contends in order to determine if a stair in a route of exit travel is "exposed to fire in the exterior wall of another fire compartment" it is reasonable to project a horizontal angle of 45 degrees from the edge of the opening with a 3 meter arc. This "rule of thumb" is used in other Code requirements, such as wall and exit exposures, where the angle of intersection of the walls is less than 135 degrees.
The appellant considers the path of travel for egress from each suite unique and separate from the path of the other suite.
Building Official's Position
The Building Official contends that Sentence 22.214.171.124.(1) does not specify a 45 degree application in determining exposure to an exit stair from an unprotected opening and that any opening in a fire compartment within a horizontal distance of 3 meters must be protected.
Further, the Building Official contends for the application of Sentence 126.96.36.199.(1), as the exit pathway is the only means of egress from each suite, the pathway must be protected from openings in either suite that are within 3 meters and located in a exterior wall which intersects the exit at an angle of less than 135 degrees.
Appeal Board Decision #1547
Exposure to Exit Stairway, Sentence 188.8.131.52.(1) Reference SK-4
The Board considers the total width of the exit passageway and exit stair to be a common means of egress for both suites. It is therefore the determination of the Board that Sentence 184.108.40.206.(1) requires the protection of openings in the exterior walls of both suites that are within a horizontal distance of 3 meters to any part of the exit stair.
Exposure to exits, Sentence 220.127.116.11.(1) Reference SK-4a
The Board considers the exterior passageway and exit stairs to be part of the exit enclosure, including that portion which extends beyond the exterior wall plane of the windows. Therefore it is the determination of the Board that Clauses 18.104.22.168.(1) (a) and (b) apply, requiring the window openings to be protected with glass block or wired glass.
George Humphrey, Chair