April 18, 2013
Re: Design of Balcony Guard, Sentences 3.4.6.5.(7) & 9.8.8.6.(2) (2006 BCBC)
Project Description
This appeal relates to the climbability of a guard on an exterior balcony on a Group A Division 1 occupancy building located within a school campus. The portion of the guard between 140 mm and 900 mm above the floor consists of 6mm steel mesh with 51mm nominal (horizontal) x 102 mm nominal (vertical) openings. This is the same as standard construction safety fencing.
Sentence 3.4.6.5.(7) states "unless it can be shown that the location and size of openings do not present a hazard, a guard shall be designed so that no member, attachment or opening located within 140 mm and 900 mm above the level being protected by the guard will facilitate climbing."
The appellant contends that the design of the guard does not facilitate climbing as climbing is not “made easier,” the dictionary definition of facilitate. The projecting top rail, the narrowness of the mesh openings (46mm net) and configuration of components (verticals in front of horizontals) makes attaining a useful toe-hold practically impossible with the body upright. The appellant also points to the provisions in Sentence 9.8.8.6.(2), including clarified wording in the 2012 Code, which detail what constitutes a guard that does not facilitate climbing. If any one of the conditions described in Clauses 9.8.8.6.(2)(a) through (d) is met then the guard is deemed to conform. Clause (b) says “elements protruding from the vertical provide not more than 15 mm horizontal offset.” The mesh in this guard is only 6 mm thick and therefore does not facilitate climbing.
The building official maintains that Sentence 3.4.6.5.(7) does not specify a size of opening for a guard where climbing may be a hazard. The opening size in question is 51mm horizontally x 102mm vertically. As this is an elementary school the official feels that there is a fair chance of the presence of young children and a child’s foot size may fit into such an opening. Sentence 9.8.8.6.(2) suggests a toe space more than 45mm horizontally and 20mm vertically facilitates climbing and the openings in this guard exceed those dimensions.
It is the determination of the Board the guard in question does facilitate climbing and can present a hazard. The Board did consider the provisions of Sentence 9.8.8.6.(2) but determined that the guard did not conform to any of the clauses. In particular, the offset described in Clause (b) does not apply to the width of the wire but rather, for instance, to a ledge protruding from the side of a spindle.
George Humphrey, Chair