When are two exits required from a floor area in Ontario?
Under OBC Division B Section 3.4, most floor areas in Part 3 buildings must be served by at least two separate exits. Limited exceptions allow a single exit for small, low-occupancy floor areas.
Part 3 of the Ontario Building Code applies to larger and higher-risk buildings (generally over 600 m², over 3 storeys, or containing assembly, care or high-hazard occupancies). For these buildings the default rule is redundancy: if one exit is blocked by fire, occupants must have a second, independent way out. The exceptions in Articles 3.4.2.2. to 3.4.2.4. permit a single exit only in limited cases — such as small floor areas with low occupant loads and short travel distances — and the permitted conditions depend on occupancy classification and whether the building is sprinklered. Exit placement is also regulated: exits must be located so the travel distance limits in Subsection 3.4.2. are not exceeded, and they must be remote from each other.
Big or busy buildings need two ways out of every floor, positioned far apart, so a single fire can never trap everyone. Only small, lightly-occupied spaces can get away with one exit — and the code spells out exactly when.
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This page is provided for general information. Building code requirements depend on your specific project, occupancy and municipality, and code editions change. Always verify requirements against the current Ontario Building Code and confirm with your local building department.