BCAB #1422 - Penetration of fire separations by combustible DWV pipe Subsection 3.1.9.

July 17, 1996

BCAB #1422

Re: Penetration of fire separations by combustible DWV pipe Subsection 3.1.9.

Project Description

The project in question is a four storey wood frame residential building separated from an underground storage garage by a 2 hr concrete slab. Fire separations within the building have a 1 hr fire resistance rating. It is proposed to use combustible DWV pipe throughout the building with penetrations of fire separations being sealed with a new fire stop system currently undergoing certification for conformance to CAN4-S115, "Standard Method of Fire Tests of Firestop Systems."

Reason for Appeal

Sentence 3.1.9.4.(3) prohibits combustible drain, waste and vent (DWV) pipe from partly or wholly penetrating fire separations unless the installation complies with the requirements of Sentences 3.1.9.4.(4) to (6). Sentence 3.1.9.4.(4) permits combustible DWV pipe to penetrate fire separations providing the penetrations are sealed with a fire stop system having an F rating equal to the separation's fire resistance rating when tested in conformance with CAN4-S115 with a pressure differential of 50 Pa between the exposed and unexposed sides with the higher pressure on the exposed side. The piping cannot be in a vertical shaft.

Appellant's Position

The appellant contends that the combustible DWV piping is being installed in strict compliance with Subsection 3.1.9. The new fire stop system has successfully completed the testing required by Sentence 3.1.9.4.(4). Subject to the completion of the listing by the certification agency the fire stop system should be permitted in the building and no further testing, specifically to CAN4-S101, is required. Much of the DWV piping is located within fire rated walls and the appellant contends that the cavities within these walls are not vertical shafts because they are fire stopped and sealed at each floor.

Building Official's Position

The building official has some concerns regarding the use of the new fire stop system. Documentation submitted by the appellant does not indicate:

  • Whether or not the testing was done with a 50 Pa pressure differential.

  • What the long term effectiveness of the mechanical fire stop system is.

  • Whether or not any maintenance is required for the mechanical components.

There is also a concern that materials may be stored near the device which would interfere with its operation. Clause 3.1.9.4.(4)(b) does not permit the combustible DWV to be located in a vertical shaft and the building official maintains that the pipe within the suite walls which penetrates the floor slab above the garage and each fire rated floor assembly is in a vertical shaft.

Appeal Board Decision #1422

It is the determination of the Board that a combustible DWV system incorporating a fire stop system which conforms to the requirements of Sentence 3.1.9.4.(4) is acceptable. Sentence 3.1.9.4.(4) requires conformance with CAN4-S115 with a 50 Pa pressure differential and prohibits the pipe from being in a vertical shaft. Pipe located in the stud spaces of a frame wall is not considered to be in a shaft unless the stud space is continuous between storeys.

Neither the building code nor CAN4-S115 addresses the issue of long term effectiveness, maintenance or interference from stored materials. Therefore the Board cannot address these concerns.

George R. Humphrey, Chair