OBC DIVISION B · PART 3 · SECTION 3.3 — SAFETY WITHIN FLOOR AREAS

How long can a dead-end corridor be under the Ontario Building Code?

A dead-end public corridor is generally limited to 6 m (about 20 ft), because occupants trapped past the last cross-corridor or exit must be able to retreat quickly. Longer dead ends require redesign or a second egress route.

Code reference
Public corridors must provide access to exits in opposite directions, and a dead-end portion is permitted only where it does not exceed 6 m in length, subject to limited occupancy-specific exceptions. The intent is that no occupant is forced far down a corridor with only one way back to an exit.
OBC Division B, Article 3.3.1.9.

Paraphrased for clarity — open this provision in the BUILDAiD Library for the exact wording.

What this means in practice

Dead ends most often appear late in design when suite layouts shift and a corridor end loses its exit stair connection. Measure from the point where two-way travel is lost to the farthest point of the corridor. Fixes include relocating a stair, adding a cross-corridor connection, converting the dead end into suite space, or providing an exterior egress door. Care, treatment and detention occupancies have stricter expectations, so verify occupancy-specific provisions.

Plain language

A hallway that ends without an exit is a trap in a fire, so the Code limits these dead ends to about 6 m. Beyond that, the layout must give people a second direction to escape.

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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.