The Ontario Building Code | Light Diffusers and Lenses
9.10.17.8. Light Diffusers and Lenses
(1) Light diffusers and lenses having flame-spread ratingsthat exceed those permitted for the ceiling finish, shall conform to the requirements of Sentence 3.1.13.4.(1).
In Plain Language
Light diffusers and lenses used in ceiling fixtures have flame-spread related requirements set out in this article, since these plastic components can otherwise contribute to fire spread.
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.