The Ontario Building Code | Determination of Ratings
3.1.7.1. Determination of Ratings
(1) Except as permitted by Sentence (2) and Article 3.1.7.2., the rating of a material, assembly of materials or a structural member that is required to have a fire-resistance rating, shall be determined on the basis of the results of tests conducted in conformance with CAN/ulc-S101, "Fire Endurance Tests of building Construction and Materials".
(2) A material, assembly of materials or a structural member is permitted to be assigned a fire-resistance ratingon the basis of MMAH Supplementary Standard SB-2, "Fire Performance Ratings".
In Plain Language
Fire-resistance ratings are generally established through standardized CAN/ULC-S101 fire endurance testing, though this article also allows assigning a rating based on MMAH Supplementary Standard SB-2 instead of running an actual test.
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.