The Ontario Building Code | Protection of Fire Escapes
3.4.7.4. Protection of Fire Escapes
(1) If a fire escape serves any storey above the second, openings="http://thehandyforce.com/windows/" title ="Window installer in Toronto">openings located in a zone described in Sentence (2), including access doorway ="http://thehandyforce.com/doors/" title ="Toronto Door installer">doorways in the exterior walls of the buildingto which the fire escape is attached, shall be protected by closures conforming to Subsection 3.1.8.
(2) The zone referred to in Sentence (1) extends from any balcony, platform or stairway of a fire escape to a distance,
(a) 3 m horizontally,
(b) 10 m below, and
(c) 1 800 mm above.
In Plain Language
Where a fire escape serves a storey above the second, nearby exterior openings within a defined protection zone need fire protection, so flames coming from a window below can't cut off the fire escape route above.
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.