BCAB #1541 - Smoke Detectors in Air Handling Systems, Sentence

July 25, 2001

BCAB #1541

Re: Smoke Detectors in Air Handling Systems, Sentence

Project Description

The project in question is a 4 storey sprinklered noncombustible building with residential and institutional occupancies. A fire alarm system is installed in the building. A system is installed in the building which provides tempered outside air to the public corridors on all four levels of the building by a supply fan (pressurized corridors). There are no provisions in the system to recirculate the supply air.

Reason for Appeal

Sentence requires that an air handling system 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 objective of Sentence is to prevent the circulation of smoke. The installation of a duct-type smoke detector would only shut down the pressurization fan if the source of air, in this case air from the outside, is contaminated with smoke. The appellant further contends having the corridors pressurized during fire conditions would be beneficial, not detrimental to smoke management. Keeping the corridors under positive pressure would create a more restrictive environment for smoke migration, particularly beneficial for the means of egress and the access for firefighters.

Building Official's Position

The Building Official contends if smoke is detected in the supply duct, the pressurization fan must shut down to prevent all the public corridors in the building from being contaminated with smoke. This requires the installation of a duct type smoke detector.

Appeal Board Decision #1541

It is the determination of the Board that the corridor ventilation system in question is an air handling system and is required to conform to Sentence

George Humphrey, Chair