The Ontario Building Code | Area Increase for Unprotected Openings
3.2.3.12. Area Increase for Unprotected Openings
(1) Except as required by Sentence 3.2.3.7.(8), the maximum area of unprotected openings in any exposing building face or fire compartment of a building that is not sprinklered is permitted to be doubled if the openings are glazed with,
(a) glass block conforming to the requirements of Article 3.1.8.14., or
(b) wired glass assemblies conforming to MMAH Supplementary Standard SB-2, "Fire Performance Ratings".
In Plain Language
Where an exterior wall is not parallel to the property line, this clause explains how to calculate the effective limiting distance to use in the spatial-separation tables, since the standard perpendicular-distance approach doesn't directly apply to an angled wall.
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.