2024 Ontario Building Code Guide: Air Duct Systems and Material Requirements for London Home Builders
Sarah's Expert Insight
OBC Compliance Specialist
"The 2024 updates emphasize the critical nature of material fire-spread ratings and SMACNA compliance to ensure residential safety. Whether we are retrofitting a heritage home in London or building a luxury cottage in Muskoka, strictly adhering to Section 9.33.6 ensures that air distribution systems are not only efficient but act as a safeguard against fire propagation."
When planning a residential HVAC installation, understanding the 2024 Ontario Building Code (OBC) is essential for safety and compliance. As a leading construction contractor, empcontracting.ca Inc. your construction contractor in London, Ontario ensures that every air duct system meets the rigorous standards set out in Section 9.33.
9.33.6.1. Application of Air Duct Systems
The regulations within this subsection apply to the design and installation of air duct distribution systems for heating, ventilating, and air-conditioning (HVAC) systems serving individual dwelling units. It is important to note that if a system's rated heat input exceeds 120 kW, it must instead conform to the requirements found in Part 6 and Subsection 3.6.5 of the OBC.
9.33.6.2. Mandatory Materials for Air Duct Systems
Noncombustible Material Standards
In most residential applications, ducts, plenums, and associated fittings must be constructed from noncombustible materials such as steel, aluminum alloy, copper, or clay. This ensures maximum fire resistance within the building's infrastructure.
Permitted Combustible Materials
Combustible materials are permitted only under specific conditions to maintain fire safety:
- They must conform to Class 1 duct materials as per CAN/ULC-S110 standards.
- They cannot be used in vertical runs serving more than two storeys.
- They are prohibited in systems where air temperatures exceed 120°C.
Duct Sealants and Connectors
To prevent the spread of fire and smoke, duct sealants must have a flame-spread rating of no more than 25 and a smoke-developed classification of 50 or less. Furthermore, combustible duct connectors are limited to 4 meters in length, must be used only in horizontal runs, and are strictly prohibited from penetrating fire separations.
Compliance with SMACNA and ASHRAE
The 2024 OBC mandates that all ductwork and fittings be installed in strict conformance with SMACNA Manuals and ASHRAE Handbooks. Following these industry-standard engineering practices is a core component of how empcontracting.ca Inc. your construction contractor in London, Ontario delivers high-quality, code-compliant results.
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.