BCAB #1493 - Fire Dampers for Air Transfer Openings in Walls and Floor, Subsection 3.1.8

August 17, 1999

BCAB #1493

Re: Fire Dampers for Air Transfer Openings in Walls and Floor, Subsection 3.1.8

Project Description

The project in question is a two storey sprinklered residential building with a commercial kitchen and adjoining dinning room. Make-up air for the kitchen exhaust fan is being provided by an interconnected supply fan and a series of air transfer grilles in walls and the floor assembly between the supply fan and the kitchen.

Reason for Appeal

The building official and the designer disagree about the code conformance of the make-up air system for the NFPA 96 kitchen exhaust system.

Appellant's Position

The appellant contends that all relevant code requirements have been addressed in the installation of the various components of the make-up air system. Transfer grilles have been provided with fire dampers where the grilles are in walls or floors acting as fire separations with fire resistance ratings.

Building Official's Position

The building official maintains that the make-up air system may compromise the level of safety intended to be provided by the NFPA 13R sprinkler system. The building official also contends that the rooms through which the make-up air travels to reach the kitchen, and the kitchen itself, constitute a plenum as defined in the code and do not comply with the combustibility and flame spread rating requirements for plenums.

Appeal Board Decision #1493

It is the determination of the Board, based on the information submitted, that the fire dampers do not contravene any basic code requirements. Heat activated fire dampers are permitted in vertical and horizontal fire separations. The Board does not consider the kitchen, or any other rooms, to be a plenum as intended by the definition of plenum in Article 1.1.3.2.

George R. Humphrey, Chair