2024 Ontario Building Code: Regulations for Combustible Insulation in Noncombustible Construction
Sarah's Expert Insight
OBC Compliance Specialist
"In the growing high-rise markets of London and Oakville, and the complex custom builds in Muskoka, strictly adhering to Article 3.1.5.14 is vital for life safety and insurance compliance. At empcontracting.ca Inc. your construction contractor in London, Ontario, we ensure that every thermal barrier—from Type X gypsum to masonry—is installed with precision to meet these rigorous 2024 fire-endurance standards."
Understanding the complexities of the 2024 Building Code Compendium is essential for ensuring fire safety and compliance in modern developments. As empcontracting.ca Inc. your construction contractor in London, Ontario, we specialize in navigating these technical requirements to ensure your project meets the highest safety standards.
General Provisions for Combustible Insulation
In buildings required to be of noncombustible construction, combustible insulation is strictly regulated based on its flame-spread rating and its specific application within the structure.
Low Flame-Spread Requirements
According to Article 3.1.5.14.(2), combustible insulation is permitted if it maintains a flame-spread rating of no more than 25 on any exposed surface, or any surface exposed by cutting through the material in any direction.
Permitted Locations Without Thermal Barriers
Combustible insulation is generally permitted in the following locations within noncombustible buildings:
- Above roof decks
- Outside of foundation walls below ground level
- Beneath concrete slabs-on-ground
Thermal Barrier Requirements for Higher Flame-Spread Ratings
When insulation has a flame-spread rating between 25 and 500, the OBC requires protection through a certified thermal barrier. Standard protection methods include:
- 12.7 mm thick gypsum board (mechanically fastened)
- Lath and plaster
- Masonry or concrete
Special Considerations for High-Rise Buildings (>18m)
For buildings exceeding 18 meters in height that are not sprinklered, the requirements become significantly more stringent to mitigate fire risk in interior and exterior assemblies:
Exterior Wall Protection
Exterior walls must use a thermal barrier such as 12.7 mm gypsum board with all joints backed, taped, and filled, or masonry/concrete at least 25 mm thick to meet the 10-minute fire endurance test (CAN/ULC-S101).
Interior Walls, Ceilings, and Roof Assemblies
For interior applications in non-sprinklered high-rises, the code mandates higher-grade protection, such as 15.9 mm Type X gypsum board or thicker masonry (50 mm to 75 mm), ensuring the assembly remains in place for at least 40 minutes under fire testing conditions.
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.