BCAB #1503 - Exhaust Ducts Penetrating Fire Separations, Sentences 3.1.8.8.(2) & (3) (1992 BCBC)

March 15, 2000

BCAB #1503

Re: Exhaust Ducts Penetrating Fire Separations, Sentences 3.1.8.8.(2) & (3) (1992 BCBC)

Project Description

The project in question is a three storey office building designed in accordance with Article 3.2.2.40. The floor assemblies are noncombustible fire separations with no fire resistance rating. Air handling units on the roof serve all three floors via supply and exhaust duct risers in unrated vertical shafts. Air is supplied through horizontal ducts above the ceiling and returned via the ceiling space which acts as a return air plenum.

Reason for Appeal

Sentences 3.1.8.8.(2) and (3) permit ducts to penetrate fire separations without installing fire dampers at the penetration providing the fire separations are not required to have a fire resistance rating.

Appellant's Position

The appellant contends that fire dampers are not required where the supply ducts penetrate the vertical shaft at each floor nor are they required on the return air grills in the vertical shaft at each floor. Sentence 3.1.8.8.(2) specifically permits the omission of fire dampers in these locations.

Building Official's Position

The building official maintains that even in an unrated fire separation there is a separation to be maintained. If this is not true, the size of the duct or opening could be unlimited and a three storey interconnected floor area would be permitted.

Appeal Board Decision #1503

It is the determination of the Board that in conformance with Sentence 3.1.8.8.(2), fire dampers are not required on the return air ducts where they penetrate the walls of the vertical shaft.

George R. Humphrey, Chair