BCAB #1745 - Combustible Piping in Noncombustible Construction, Sentences 3.1.5.16.(1) & 3.1.5.17.(1)

April 16, 2014

BCAB #1745

Re: Combustible Piping in Noncombustible Construction, Sentences 3.1.5.16.(1) & 3.1.5.17.(1)

Project Description

The project in question is a new mixed-use high-rise building with Group E mercantile use on the ground floor and Group C residential on the remaining storeys. In question is the use of combustible drainage piping in cabinets under the bathroom sinks.

Reason for Appeal

  1. Sentence 3.1.5.16.(1) limits the flame spread rating and smoke developed classification of combustible piping to 25 and 50 respectively unless the piping is concealed in a wall or concrete floor slab.
  2. Sentence 3.1.5.17.(1) permits combustible plumbing fixtures in noncombustible construction providing they have a flame spread rating and smoke developed classification not more than that permitted for the wall surface of the room in which they are located.

Appellant's Position

  1. The appellant contends that no flame spread or smoke developed limits apply to combustible piping within a wall assembly or a concrete floor slab.
  2. Based on Appeal #382 (Sept. 7, 1979) the appellant contends that the piping connecting the sinks to the piping in the walls is part of the fixture. As part of the fixture it should be governed by Sentence 3.1.5.17.(1) and Table 3.1.13.7. which allow a smoke developed classification of 300, the limit for walls in “other” locations Table 3.1.13.7.

Building Official's Position

  1. The building official agrees that combustible piping in a wall or concrete slab is not limited to a flame spread limit of 25 or a smoke developed classification of 50. However, he does not consider the piping in the cabinet below the sink to be in a wall or concrete floor slab so it must conform to the flame spread and smoke developed limits in Sentence 3.1.5.16.(1)
  2. Based on current BC Plumbing Code definitions of fixture, fixture outlet pipe and plumbing system the building official does not consider the piping in the cabinet below the sink, including the fixture outlet pipe, tailpiece adapter, P-trap and fixture arm, to be part of the fixture. Therefore, this piping is not eligible for the smoke developed classification of maximum 300 permitted for combustible fixtures in Sentence 3.1.5.17.(1) and Table 3.1.13.7.

Appeal Board Decision #1745

It is the determination of the Board that the fixture outlet pipe, tailpiece adapter, P-trap and fixture arm are not part of the fixture and as they are not contained within a wall or concrete floor slab must meet the flame spread rating and smoke developed classification required by 3.1.5.16.(1).

Lyle Kuhnert, Chair