The Ontario Building Code | Combustibility of Service Penetrations
3.1.9.2. Combustibility of service Penetrations
(1) Except as permitted by Articles 3.1.9.3. and 3.1.9.4., pipes, ducts, electrical outlet boxes, totally enclosed raceways or other similar service equipment that penetrate an assembly required to have a fire-resistance rating shall be noncombustible unless the assembly has been tested incorporating that service equipment.
In Plain Language
Service equipment (pipes, ducts, electrical boxes, raceways) that penetrates a rated assembly generally must itself be noncombustible, unless that exact equipment was included when the assembly was originally fire-tested.
This is a plain-language summary of the 2012/2017 Ontario Building Code text above, for general understanding only and not a substitute for the Code. Always confirm current requirements against the 2024 edition (O.Reg. 163/24) or a qualified professional before construction.