BCAB #1532 - Smoke Detectors in Air Handling Systems, Sentence 3.2.4.12.(1)

March 22, 2001

BCAB #1532

Re: Smoke Detectors in Air Handling Systems, Sentence 3.2.4.12.(1)

Project Description

The subject building is a 4 storey sprinklered noncombustible building with residential and institutional occupancies. The building incorporates a common system for bathroom exhaust that complies with Sentences 3.1.8.8.(1) and 3.6.3.4.(1) and serves suites located on different storeys. A fan at the roof level maintains a negative pressure within the main exhaust riser.

Reason for Appeal

Sentence 3.2.4.12.(1) requires that an air handling system to be designed to prevent the circulation of smoke upon a signal from a duct-type smoke detector if the air handling system serves more than one storey.

Appellant's Position

The appellant contends the exhaust system being under a constant negative pressure inherently prevents the migration of smoke, by exhausting the smoke to the exterior.

Building Official's Position

The Building Official maintains that Sentence 3.2.4.12.(1) requires a duct-type smoke detector be installed in the main exhaust riser to shut down the exhaust fan in the event of smoke in the riser.

Appeal Board Decision #1532

It is the determination of the Board that for the purposes of Sentence 3.2.4.12.(1) a common exhaust system used for bathroom exhaust is not considered an air handling system as defined in common construction dictionaries. A duct-type smoke detector is therefore not required.

George Humphrey, Chair