BCAB #1795 - Required Floor Drain in Basement, Article 9.31.4.3.

January 27, 2017

BCAB #1795

Code Edition: 2012
Code Division: B
Code Reference: Part 9

Re: Required Floor Drain in Basement, Article 9.31.4.3.

Project Description

The project is a residential duplex with an in-ground basement and crawlspace. The crawlspace contains a furnace and storage-type service water heater which is served by a floor drain. The adjoining basement has a floor level approximately 1.5m lower than the crawl space floor, and is not served by a floor drain.

The building site is serviced by city sanitary and storm sewers providing gravity drainage. The floor level of the basement is below the building sanitary sewer where it enters the building requiring a lift pump for the basement’s plumbing facilities. The basement floor is also lower than the invert elevation of the city storm sewer provided to the site. It would be impractical for a floor drain in the basement to drain by gravity to a dry well or a drainage ditch.

Applicable Code Requirements

Sentence 9.31.4.3.(1) states:

1) Where gravity drainage to a sewer, drainage ditch or dry well is possible, a floor drain shall be installed in a basement forming part of a dwelling unit.

Decision Being Appealed (Local Authority’s Position)

The local authority has determined that a floor drain is required in the basement. The lift pump is considered to be part of the system providing a connection to the city’s sewer connection which is gravity fed. The Code’s attributions [F40, F41, F62-OH1.2, OH1.3] [F62-OH1.1] support this reasoning.

Appellant's Position

The appellant contends that because gravity drainage is not possible, a floor drain is not required to be installed in the basement. The inverts of sanitary and storm sewer are higher than the basement top of slab and therefor a floor drain cannot be drained by gravity. If a floor drain was provided, it would need to be pumped.

Sentence 9.31.4.3.(1) refers to a basement and not the lowest part of the basement.

Appeal Board Decision #1795

It is the determination of the Board that a floor drain in the basement is not required.

Reason for Decision

  • Information provided to the Board indicates that direct drainage by gravity from a basement floor drain to a sewer, drainage ditch, or dry well is not possible.
  • The Board does not consider the discharge from a floor drain being pumped to a higher elevation and then drainage by gravity meets the intention of “gravity drainage” for a floor drain in Sentence 9.31.4.3.(1).

Lyle Kuhnert
Chair, Building Code Appeal Board

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