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

What fire separations are required for hazardous rooms under the Ontario Building Code?

Rooms with elevated fire hazard, such as storage rooms with combustible material, repair garages, and rooms containing flammable liquids, must be separated from the rest of the floor area by rated fire separations, commonly 1 h or 2 h depending on the hazard.

Code reference
Spaces presenting a hazard to the rest of a floor area must be enclosed in fire separations with prescribed fire-resistance ratings, with the rating and any sprinkler or ventilation demands set by the specific hazard, such as combustible storage, flammable and combustible liquids, or vehicle repair. Service rooms are addressed separately under Part 3 service provisions.
OBC Division B, Subsection 3.3.1.

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

What this means in practice

In practice, flag every janitor storage room, paint area, waste and linen room, and vehicle-related space during design, because each has its own enclosure, closure and rating rules scattered through 3.3, 3.6 and referenced standards such as the Ontario Fire Code for liquids. Doors must be rated closures with self-closers, and penetrations fire stopped. Missed hazardous-room ratings are among the most common occupancy-permit deficiencies, especially in industrial and mixed-use fit-outs.

Plain language

Rooms that are more likely to start or feed a fire, like paint rooms, garages or big storage rooms, must be boxed in with fire-rated walls and self-closing doors so a fire there stays put long enough for everyone to leave.

Related questions

What fire separation is required between suites in Ontario?What is the minimum corridor width under the Ontario Building Code?How long can a dead-end corridor be under the Ontario Building Code?

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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.