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

What are the requirements for vertical service spaces and shafts in Ontario?

Shafts (vertical service spaces) must be enclosed in fire separations, generally rated to match the fire-resistance required for the floor assemblies they penetrate, with rated closures at openings and appropriate protection at the top and bottom of the shaft.

Code reference
Vertical service spaces that penetrate floor assemblies must be enclosed by fire separations whose fire-resistance rating is coordinated with the rating of the assemblies penetrated, with permitted reductions in certain sprinklered conditions. Openings need rated closures, shaft tops and bottoms must be appropriately closed, and incompatible services such as refuse chutes require dedicated shafts.
OBC Division B, Subsection 3.6.3.

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

What this means in practice

Every duct riser, plumbing stack chase, elevator hoistway and linen or refuse chute is a potential chimney for fire and smoke, which is why shaft continuity matters so much on site. Design shafts with buildable rated assemblies (shaft wall systems are common), maintain the rating through every floor, and detail access doors with matching ratings. The most frequent deficiencies are unrated access panels, missing firestopping where services exit the shaft, and mixing services in a shaft that should be dedicated.

Plain language

The hidden vertical chases that carry ducts, pipes and chutes between floors must be built like fire-rated tubes, sealed at every floor and access door. Otherwise a fire on one level could race straight up through the building.

Related questions

What fire separation is required for service rooms in Ontario?Where can fuel-fired appliances be located in a Part 3 building in Ontario?What does the Ontario Building Code require for electrical vaults and transformer rooms?

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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.