BCAB #1221 - Transition Treads in Curved Stairs - Clause 3.3.1.15.(8)(b)

October 23, 1990

BCAB #1221

Re: Transition Treads in Curved Stairs - Clause 3.3.1.15.(8)(b)

Project Description

Curved stairs in any occupancy.

Reason for Appeal

Sentence 3.3.1.15.(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."

Appellant's Position

The appellant maintains Sentence 3.3.1.15.(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 3.3.1.15.(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