BCAB #1485 - Fire Separations in Crawl Spaces, Sentence 3.1.8.3.(1) (1992 BCBC)

June 28, 1999

BCAB #1485

Re: Fire Separations in Crawl Spaces, Sentence 3.1.8.3.(1) (1992 BCBC)

Project Description

The project in question involves several wood frame townhouse and apartment buildings of two and four storeys in building height. Some of the buildings are governed by Part 3 and others by Part 9.

Reason for Appeal

Sentence 3.1.8.3.(1) requires the continuation of vertical fire separations through horizontal service spaces or other concealed spaces located above the vertical fire separation.

Appellant's Position

The appellant contends that Sentence 3.1.8.3.(1) specifically addresses the continuation of vertical fire separations only into concealed spaces above the fire separation. Concealed spaces such as crawl spaces located below a vertical fire separation are not required to have the vertical fire separations continue down through the crawl space. The Code accepts that fires are less likely to spread down into a concealed space than into a concealed space located above. Building Standards Branch Interpretation 94-25 supports this contention when it states that construction in a crawl space that supports a vertical fire separation in the storey above is not required to have a fire resistance rating.

Building Official's Position

The building official maintains that in order to provide the suite to suite fire separation required by Sentence 9.10.9.14. (1) the fire rated wall must be a continuous partywall from slab to roof deck or the floor assembly would have to be fire rated from the underside. There is also a concern that the suite to suite STC rating won't be achieved unless the sound rated partywall is carried down to the crawl space slab.

Appeal Board Decision #1485

It is the determination of the Board that no fire separation is required in the crawl space below the suite separation walls. Sentence 3.1.8.3.(1) is not applicable to this case because the crawl space is not a horizontal service space. Sentence 3.2.2.5.(2) exempts the floor above an unoccupied crawl space from the need to be constructed as a fire separation with a fire resistance rating. Clause 3.3.4.2.(1)(b) reinforces this exemption. Part 9 has similar requirements in Article 9.10.8.8. and Sentence 9.10.9.4.(4). The Board notes that the sound transmission requirements between suites must still be addressed.

George R. Humphrey, Chair