BCAB #1221 - Transition Treads in Curved Stairs - Clause 220.127.116.11.(8)(b)
October 23, 1990
Re: Transition Treads in Curved Stairs - Clause 18.104.22.168.(8)(b)
Curved stairs in any occupancy.
Reason for Appeal
Sentence 22.214.171.124.(8) permits stairs containing tapered treads (curved stairs) to change direction provided there are "at least 3 parallel transition treads between each change in direction."
The appellant maintains Sentence 126.96.36.199.(8) only applies where a curved stair changes direction. It is not required that there be at least 3 parallel treads in any any straight portion where the direction does not change such as at the top or bottom of a flight.
Building Official's Position
No comments were received from the building official. The appellant's letter indicates the building official's interpretation of this Sentence is that a curved stair with 12 tapered treads and one parallel tread at the bottom would not be permitted. Such a stair would require 3 parallel treads at the bottom before the tapered treads started.
Appeal Board Decision #1221
The Board does not consider that Clause 188.8.131.52.(8)(b) requires at least three parallel treads at the the beginning and/or end of a flight of stairs. It is the determination of the Board that this Clause requires the insertion of three parallel transition treads only where a curved stair changes from a right hand to a left hand curve or vice versa.
George R. Humphrey, Chair