The Ontario Building Code | Ceilings in Exits or Public Corridors
9.10.17.2. ceilings in Exits or Public corridors
(1) At least 90% of the exposed surface of every ceiling in an exitor unsprinklered ceiling in a public corridor shall have a surface flame-spread rating of not more than 25.
In Plain Language
Ceilings in exits or public corridors have specific flame-spread requirements set out in this article, reflecting the critical importance of these escape routes remaining survivable during a fire.
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.