In Plain Language

Fully enclosed nonmetallic raceways used inside a plenum in combustible-construction buildings must meet the specific material requirements set out in Clause 3.1.5.20.(1)(a).

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.