BCAB #1412 - Suite Ventilation Make-Up Air, Article 9.32.3.4

February 21, 1996

BCAB #1412

Re: Suite Ventilation Make-Up Air, Article 9.32.3.4

Project Description

The project in question is a three storey apartment building. The suites are heated with electric baseboards and a humidistat controlled ventilation system is provide in each suite. Suites are also provided with naturally aspirating gas fireplaces.

Reason for Appeal

Article 9.32.3.4. requires make-up air for the ventilation system. Sentence 9.32.3.4.(1) requires this air to come from the exterior and, due to the geographic location of the building, Sentence (3) requires it to be tempered.

Appellant's Position

The appellant contends that tempered make-up air can be provided from the public corridor serving the suites. These corridors are provided with outside air from an air handling unit and ducts to each corridor. If a fire damper equipped transfer grille is provided through the fire separation between the corridor and the suite, the make-up air will be tempered by its passage through the heated corridor.

Building Official's Position

The building official maintains that make-up air must be provided from the exterior of the building to each suite by one of the methods in Clause 9.32.3.4.(3)(b). Subclauses (ii) - heating/fan unit, (iii) - heat recovery ventilator and (iv) - other acceptable methods, could be applied. A transfer grille between the public corridor is not acceptable to the building official at least partly because it does not conform to Sentence 6.2.3.11.(2) which states "In a residential occupancy, air from one suite shall not be circulated to a public corridor." Another concern is that fire dampers in this location would not prevent the circulation of smoke unless they were triggered by the fire alarm system. Clause 3.2.4.13.(1)(b) seems to support this concern.

Appeal Board Decision #1412

Although the Board does not consider the Code to preclude a fire damper equipped transfer grille in a fire separation between a public corridor and a suite it is not acceptable in this case because the sound transmission class (STC) rating required by Articles 3.3.4.6. or 9.11.2.1. would not be achieved.

George R. Humphrey, Chair