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OBC DIVISION B · PART 3 · SECTION 3.6 — SERVICE FACILITIES

Where can fuel-fired appliances be located in a Part 3 building in Ontario?

Fuel-fired appliances generally must be located in a dedicated service room with a fire separation of at least 1 h, must not be placed in or under exits, and need combustion air and installation per CSA B149.1 or the applicable fuel code.

Code reference
Fuel-fired space-heating appliances, water heaters and similar equipment in Part 3 buildings are generally required to be in service rooms enclosed by fire separations of not less than 1 h, and are prohibited in exits and in locations that would endanger means of egress. Installation, venting and combustion air must follow the applicable fuel safety standards.
OBC Division B, Subsection 3.6.2.

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

What this means in practice

The recurring design issues are location and air: keep fuel-fired equipment out of exit stair enclosures and away from egress routes, and confirm combustion and dilution air openings or ducts sized to CSA B149.1 for gas or CSA B139 for oil. Rooftop units and some sealed-combustion equipment can reduce the need for interior service rooms. Watch for later tenant fit-outs that add unit heaters or water heaters in closets without separations, a frequent source of occupancy-permit delays.

Plain language

Gas- or oil-burning equipment has to live in its own fire-rated room, never inside or underneath an exit stair, and it needs a guaranteed supply of air to burn safely. Separate fuel safety codes govern exactly how it is hooked up and vented.

Related questions

What fire separation is required for service rooms in Ontario?What does the Ontario Building Code require for electrical vaults and transformer rooms?What are the requirements for vertical service spaces and shafts in Ontario?

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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.