BCAB #1471 - Fire Stopping at Bathroom Drop Ceiling, Sentences 3.1.11.2.(1) and 3.1.11.4.(1)

August 19, 1998

BCAB #1471

Re: Fire Stopping at Bathroom Drop Ceiling, Sentences 3.1.11.2.(1) and 3.1.11.4.(1)

Project Description

The project in question is a sprinklered high-rise residential building of noncombustible construction. Interior walls are constructed of steel studs and gypsum board. There are drop ceilings in the bathrooms to conceal combustible sprinkler and water distribution pipes (water pipe accepted under Section 2.5). The bathtubs are fiberglass/acrylic with a flame spread rating exceeding 25 and no gypsum board is used behind the tubs.

Reason for Appeal

Sentence 3.1.11.2.(1) requires fire stopping ... "to block off concealed spaces within a wall assembly ... at every ceiling level where the ceiling forms part of a assembly required to have a fire resistance rating..." Sentence 3.1.11.4. (1) requires fire stopping ... "at all interconnections between concealed vertical and horizontal spaces in ... drop ceilings ... in which exposed construction materials within the space have a flame spread rating of more than 25 ..."

Appellant's Position

The appellant contends that Sentence 3.1.11.2.(1) does not require fire stopping between wall cavities and the ceiling space because the drop ceiling is not part of an assembly with a fire resistance rating. However, NFPA 13 requires ceiling spaces containing exposed combustibles to be sprinklered. Since the combustible tubs are exposed to the wall cavities, which in turn are exposed to the ceiling spaces, either the wall cavities must be fire stopped or the ceiling spaces sprinklered.

Building Official's Position

The building official maintains that fire stopping is required at the ceiling/wall intersection in accordance with Sentence 3.1.11.4.(1) to prevent the spread of fire from the drop ceiling space to the exposed combustible tubs adjoining the wall cavity.

Appeal Board Decision #1471

It is the determination of the Board that Sentence 3.1.11.4.(1) applies and fire stopping is required between the vertical space within the wall and the horizontal space within the drop ceiling. Sentence 3.1.11.2.(1) is not applicable because the ceiling does not form part of an assembly required to have a fire resistance rating.

George R. Humphrey, Chair