The Ontario Building Code | Exit Width Reduction
3.4.3.4. Exit Width Reduction
(1) Except as permitted by Sentences (2) to (4), no fixture, turnstile or construction shall project into or be fixed within the required width of an exit.
(2) Exit doors shall be hung so that, when open, they shall neither diminish nor obstruct the required width of the exit by more than 50 mm for each door leaf.
(3) Swinging doors in their swing shall not reduce the required width ofexit stairs or landings to less than 750 mm or reduce the width of an exit passageway to less than the minimum required width.
(4) handrails and construction below handrails are permitted to project into the required width of means of egress but the projections shall be not more than 100 mm on each side of the required width.
(5) In an elementary or secondary school, where a stair lift is installed in an exit stair, an intermediate handrail shall be installed between the path of travel of the stair lift and the remainder of the stair to ensure that the stair lift will not reduce the required width of the exit stair.
In Plain Language
Nothing may project into or reduce the required clear width of an exit, though exit doors are allowed to intrude up to 50 mm per leaf when open, and other narrow exceptions apply for specific fixtures.
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.