2024 Ontario Building Code Guide: Combustible Materials in Noncombustible Construction
Sarah's Expert Insight
OBC Compliance Specialist
"When managing complex commercial developments in London or Oakville, balancing noncombustible requirements with functional design elements like skylights is a frequent challenge. At empcontracting.ca Inc. your construction contractor in London, Ontario, we emphasize that even 'minor' components like wood blocking or pneumatic tubing require precise firestop conforming to Article 3.1.11.7. to pass rigorous municipal inspections in the Muskoka and Southwestern Ontario regions."
Understanding the nuances of the 2024 Ontario Building Code (OBC) is essential for any major commercial or high-density residential project. At empcontracting.ca Inc. your construction contractor in London, Ontario, we specialize in navigating these complex requirements to ensure your build is both compliant and efficient.
3.1.5.3. Combustible Roofing Materials
In buildings where noncombustible construction is mandated, the OBC provides specific allowances for combustible roofing components. This includes roof coverings with A, B, or C classifications as per Subsection 3.1.15.
Sheathing and Support Requirements
Combustible roof sheathing and supports may be installed above concrete decks provided the deck is at least 50 mm thick and the roof space height does not exceed 1 meter. Furthermore, these spaces must be appropriately compartmentalized using fire blocks and protected by noncombustible parapets or masonry shafts for building services.
Ancillary Roofing Components
Small-scale combustible items such as cant strips, roof curbs, and nailing strips are permitted. Additionally, wood nailer facings on parapets under 610 mm are allowed, provided they are protected by sheet metal to mitigate fire spread risk.
3.1.5.4. Combustible Windows, Glazing, and Skylights
The OBC allows for combustible skylight assemblies in noncombustible buildings, subject to strict flame-spread ratings and area limitations.
Skylight Assembly Standards
- Flame-Spread Rating 150: Permitted if the individual area is under 9 m² and the aggregate area does not exceed 25% of the ceiling space.
- Flame-Spread Rating 75: Permitted for larger individual areas up to 27 m², provided the aggregate area is no more than 33% of the ceiling.
Vertical Glazing and Safety
Combustible vertical glazing is permitted up to the second storey. Generally, this glazing must maintain a flame-spread rating of no more than 75 to ensure the safety of the building envelope and its occupants.
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.