OBC 2024 Guide: Group C Residential Fire Safety for 4-6 Storey Buildings
Sarah's Expert Insight
OBC Compliance Specialist
"The expansion of 6-storey combustible construction in the 2024 OBC is a significant opportunity for developers in London and Oakville to increase housing density efficiently. At empcontracting.ca Inc. your construction contractor in London, Ontario, we find that the most critical factor in these projects is the precise execution of the 1-hour fire-resistance ratings and the integration of advanced sprinkler systems to ensure total code compliance and occupant safety."
The 2024 Ontario Building Code (OBC) Compendium introduces specific requirements for Group C (Residential) occupancies, particularly focusing on fire-resistance ratings and building height limits. Navigating these complexities is essential for modern mid-rise developments in Ontario.
3.2.2.50. Noncombustible Construction for 4-Storey Buildings
Residential buildings classified as Group C (excluding retirement homes) may utilize noncombustible construction for structures up to 4 storeys. However, the 4-storey allowance is strictly regulated: the building must not have more than one dwelling unit stacked above another, and vertical fire separations must be continuous through all storeys.
Fire-Resistance and Area Requirements
- Fire-Resistance Ratings: Floor, roof, and loadbearing assemblies generally require a minimum 1-hour fire-resistance rating.
- Building Area: Maximum area is determined by street frontage. For a 4-storey building facing three streets, the maximum area is 4,500 m².
- Internal Dwelling Units: Floor assemblies contained entirely within a multi-storey dwelling unit must have a 1-hour rating but do not necessarily require fire separations.
3.2.2.51. Combustible Construction for 6-Storey Sprinklered Buildings
OBC 3.2.2.51 allows for increased density using combustible construction, provided the building is fully sprinklered. This provision is vital for mid-rise wood-frame developments.
Compliance Criteria for 6-Storey Residential
To conform to these standards, the building must be sprinklered throughout and not exceed a height of 18 meters from the first storey floor to the uppermost floor level. Building area limits decrease as height increases, with a 3-storey building capped at 3,000 m² under this specific clause.
Expert Guidance from empcontracting.ca Inc. your construction contractor in London, Ontario
Ensuring that your multi-family project meets the 2024 fire-resistance standards is critical for both safety and legal compliance. Whether you are building in urban London or the growing areas of Oakville and Muskoka, empcontracting.ca Inc. your construction contractor in London, Ontario provides the technical expertise to manage these complex OBC requirements from design to final inspection.
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.