BCAB 1798 - Fire separations of exits

Fire separations of exits

Project description

The subject is a single suite, two-storey building of Group D, business and personal service occupancy, to which Part 9 of Division B of the British Columbia Building Code applies. The upper storey is served by a single stair separated from the lower storey by a fire separation. This stair provides the only egress from the upper storey. The stair is open to the upper storey as there is no door/closure at the top of the stair. An exit door providing direct access to the outdoors is provided at the bottom of the stair. There are two doors connecting the lower storey to the stair. The exit system for the lower storey is not dependent on the exit door at the bottom of the stair. The upper storey is less than 100m² in area, and the lower storey is greater than 100m² in area.

Applicable Code requirement

Sentence 9.9.4.2.(1) of Division B of the 2012 British Columbia Building Code

9.9.4.2.(1) Except as provided in Sentence (2) and (5) and Article 9.9.8.5., every exit other than an exterior doorway shall be separated from each adjacent floor area or from another exit

(a) where there is a floor assembly above the floor area, by a fire separation having a fire-resistance rating not less than that required for the floor assembly above the floor area (see Article 9.10.9.10.), and

(b) where there is no floor assembly above the floor area, by a fire separation having a fire-resistance rating not less than the greater of

(i) that required by Subsection 9.10.8. for the floor assembly below, or

(ii) 45 min.

Decision Being appealed (Local authority’s position)

The local authority has determined that one of the required means of egress for the lower storey is through the area at the bottom of the stair.

The local authority has determined two options for Code compliance:

• To consider the stair to be an exit stair, the stair must be separated from both upper and lower storeys as an exit which would include a door at the top of the stair, or
• To consider the stair to be part of the upper storey, there cannot be a circulation space for the lower level through the area at the bottom of the stair considered to be an extension of the upper storey.

The permission in Article 9.9.4.7. that the stairs need not be constructed as exit stairs does not apply to this project as the lower storey exceeds the maximum floor area of 100 m² as listed in Clause (1)(c).

Appellant's position

The appellant contends that the stair is the extension of the upper storey and does not require additional separation from the upper storey. A fire separation is provided between the stair and the remainder of the lower storey. A required means of egress serving the lower storey does not pass through the area at the bottom of the stair. Lower storey access through the area at the bottom of the stair is provided for convenience and circulation.

Appeal Board Decision #1798

It is the determination of the Board that the stair can be considered part of the upper storey and need not be separated from it by a door at the top. Further, the Board does not consider the area at the bottom of the stair as being required to serve as a means of egress for the lower storey, and can be accessed for convenience and circulation for the lower storey.

Reason for decision

The Board considers the required exit for the upper storey to be the exterior door at the bottom of the stair, and not the stair itself. The lower storey is served by other exits, and it is not necessary to reach these other exits by passing through the area at the bottom of the stair.

This decision is consistent with the principles applied in the previous Appeal Board decisions #1486, #1684, and #1695.

Lyle Kuhnert
Chair, Building Code Appeal Board