OBC Fire Separation Requirements for Residential & Mercantile Suites | London, Ontario
Sarah's Expert Insight
OBC Compliance Specialist
"Navigating fire-resistance ratings for mixed-use and secondary suites is vital for legal compliance and tenant safety in growing markets like London, Oakville, and Muskoka. At empcontracting.ca Inc., your construction contractor in London, Ontario, we recommend using 15.9 mm Type X gypsum or professional sprinkler systems to streamline inspections while meeting the rigorous 2024 OBC standards for smoke-tight barriers."
Understanding the Ontario Building Code (OBC) is essential for any successful renovation or new build. As empcontracting.ca Inc. your construction contractor in London, Ontario, we prioritize safety and compliance when managing mixed-use and residential developments.
Fire Separation for Mixed-Use: Residential and Mercantile
According to Section 9.10.9.13 of the OBC, residential occupancies (including live/work units) must generally be separated from mercantile or medium-hazard industrial occupancies by a fire separation with a rating of at least 2 hours. However, a reduction to a 1-hour fire-resistance rating is permitted if the building contains no more than two dwelling units alongside a mercantile occupancy.
Residential Suites in Industrial Environments
OBC 9.10.9.14 restricts residential units in Group F, Division 2 industrial buildings to a maximum of one suite, unless the occupancy is directly related to a live/work unit configuration. This ensures that residential safety is not compromised by industrial activity.
General Suite Separation Standards
Standard Suite Fire Ratings
Section 9.10.9.15 mandates that most suites must be separated from adjoining suites by a fire separation of at least 45 minutes. In sprinklered buildings, certain business, personal service, and mercantile suites may be exempt from this requirement if they share public corridors meeting specific code criteria.
Specific Rules for Residential Suites
Residential suites typically require a 45-minute fire-resistance rating. However, for dwelling units spanning two or more storeys, this requirement increases to a 1-hour rating. For homeowners in London or Oakville looking to add secondary suites, the code offers a practical alternative: using a continuous smoke-tight barrier of 15.9 mm Type X gypsum board on both sides of walls and the underside of floor-ceiling framing.
Sprinkler Exemptions
If a house with a secondary suite is fully sprinklered, the specific fire-resistance rating requirements for the separation may be waived, providing more flexibility in design and material choice.
Disclaimer: This content is generated from the Ontario Building Code for educational purposes. Always consult with a licensed professional engineer or your local building department before starting any construction project in London, Ontario.