The Ontario Building Code | Flame-Spread Rating
22.214.171.124. Flame-Spread Rating
(1) Where a flame-spread rating is required in this Section for an element of a building, such rating shall be determined in accordance with the test methods described in Part 3, or in accordance with MMAH Supplementary Standard SB-2, "Fire Performance Ratings".
(2) Unless the flame-spread rating is referred to in this Part as a "surface flame-spread rating", it shall apply to any surface of the element being considered that would be exposed by cutting through it as well as to the exposed surface of the element.