BCAB #1440 - Fire-Resistance Rating of Balcony at Scupper, Article 18.104.22.168.
May 15, 1997
Re: Fire-Resistance Rating of Balcony at Scupper, Article 22.214.171.124.
The project in question is a three storey wood frame apartment building over a concrete parking garage. The balconies are drained by scuppers which penetrate through the balcony structure near the exterior wall of the building.
Reason for Appeal
Article 126.96.36.199. requires balconies to have the same fire-resistance rating as the floor assemblies in the building or the exposing building face, which ever is more restrictive.
The appellant contends that the fire-resistance rating of the balcony structure is maintained at the scupper because the structural members adjacent to the opening are protected by the same membrane that is applied to the underside of the balcony. The required 3/4 hour fire-resistance rating is provided by the membrane alone in conformance with Chapter 2 of the Supplement to the National Building Code 1990. The opening for the scupper is completely lined with this membrane, including the underside of the plywood decking.
Building Official's Position
The building official maintains that the fire-resistance rating is not maintained at the scupper opening because Article 2.3.15. of the supplement says: "Where the fire-resistance rating of a ceiling assembly is to be determined on the basis of the membrane only and not of the complete assembly, the ratings may be determined from Table 2.3.H., provided no openings are located within the ceiling membrane." The building official considers the opening for the scupper to be an opening "... located within the ceiling membrane ..." as intended in Article 2.3.15. Therefore, Table 2.3.H. cannot be used to determine a fire resistance rating for the balcony.
Appeal Board Decision #1440
It is the determination of the Board that the scupper design does not contravene the requirement for a fire resistance rating for the balcony structure. Although there is an opening in the gypsum board membrane where the scupper penetrates the plywood decking this opening would have no adverse effect on the fire resistance rating of the balcony structure. The Board considers the Supplement's reference to openings in the membrane is referring to typical openings for items such as diffusers, fans and pot lights which would expose the structure above the membrane to the fire.
George R. Humphrey, Chair