BCAB #1287 - Combustible Water Closet Flanges & Basin Arms, Articles 3.1.7.3. & 9.10.9.2.

July 29, 1992

BCAB #1287

Re: Combustible Water Closet Flanges & Basin Arms, Articles 3.1.7.3. & 9.10.9.2.

Project Description

The project in question is a wood framed apartment building with floor assemblies consisting of 37.5 mm of concrete on plywood subflooring on wood joists with a gypsum board ceiling membrane. The water closets are set on combustible plastic floor flanges which are in turn connected to the noncombustible drain, waste and vent piping. The arms connecting the basin traps to the noncombustible riser are also plastic.

Reason for Appeal

Sentence 3.1.7.3.(1) prohibits the use of combustible piping in a drain, waste and vent system where any part of that system penetrates a fire separation required to have a fire resistance except as permitted by Sentences (2) to (4). Sentence (3) permits combustible drain, waste and vent piping to penetrate a concrete floor slab provided it leads directly to a noncombustible water closet. Sentence (4) permits combustible drain, waste and vent piping to be used on one side of a fire rated wall as long as it not in a vertical shaft.

Appellant's Position

The appellant contends that the plastic water closet flanges should be acceptable because they are in a concrete floor slab and are attached directly to a noncombustible water closet. He considers the plastic basin arms to be acceptable because they connect the permitted plastic trap to a noncombustible riser which is not located in a fire separation.

Building Official's Position

The building official does not consider the 37.5 mm concrete topping on the wood frame floor assembly as being within the intent the term "concrete floor slab" in Sentence 3.1.7.3.(4). Therefore, the official maintains that the water closet flange is a combustible penetration of the fire separation and must be protected by a fire stop device conforming to CAN4-S101 or must be noncombustible.

In regards to basin arms the building official refers to Appeal #382 confirming an earlier appeal which considered the basin arm or fixture drain to be between the basin trap and the rest of the drainage system and, therefore, part of the drainage system not the fixture. In accordance with Sentence 3.1.7.3.(1) the drain, waste and vent system must be of noncombustible pipe where any part of the system penetrates a fire separation as it does in this building.

Appeal Board Decision #1287

It is the determination of the Board that the concrete topping on the wood frame floor assembly does not constitute a "concrete floor slab" as intended by the Code and, therefore, Sentence 3.1.7.3.(3) does not apply.

Regarding the basin arms, the drain, waste and vent system penetrates horizontal fire separations so all the piping must be noncombustible in conformance with Sentence 3.1.7.3.(1), including the basin trap arms connecting the wash basins to the riser.

George R. Humphrey, Chair