Ontario Building Code 9.32.3.10 & 9.32.3.11: Ventilation and Ductwork Standards in London, Ontario
Sarah's Expert Insight
OBC Compliance Specialist
"Adhering to RSI 0.5 insulation and meticulous mastic sealing is vital in the London and Muskoka regions to prevent interstitial condensation during our freezing winters. At empcontracting.ca Inc. your construction contractor in London, Ontario, we go beyond the minimum requirements to ensure your ventilation system is silent, efficient, and fully compliant with the 2024 OBC standards."
Understanding the complexities of the 2024 Ontario Building Code (OBC) is essential for any successful residential or commercial renovation. At empcontracting.ca Inc. your construction contractor in London, Ontario, we prioritize compliance and quality in every ventilation installation.
9.32.3.10. Maximum Sound Rating for Fans
To ensure occupant comfort, the OBC mandates specific sound ratings (measured in sones) for exhaust fans. Fans rated according to HVI 915 or CAN/CSA-C260-M must meet the following criteria:
- Principal Exhaust Fans: Maximum 2.0 to 2.5 sones.
- Supplemental Bathroom Fans: Maximum 2.5 to 3.5 sones.
- Kitchen Exhaust Fans: No specific sound rating required under this section.
9.32.3.11. Ventilation Ductwork Requirements
Proper duct installation is critical for system efficiency and preventing moisture-related issues within the building envelope.
Duct Materials and Construction
Exhaust ducts serving bathrooms may be made of combustible materials if they are airtight and water-impervious. However, cooking appliance exhaust fans must use noncombustible, corrosion-resistant materials and lead directly to the outdoors with no other connections.
Insulation and Vapour Barriers
To prevent condensation, the OBC requires:
- Ducts passing through unheated spaces must be insulated to at least RSI 0.5.
- Ducts carrying un-tempered outdoor air through heated spaces must be insulated to RSI 0.5 and equipped with a vapour barrier.
Installation, Sealing, and Support
All ductwork must be permanently supported to prevent sagging and installed to avoid crushing. Joints must be sealed using professional-grade mastic, metal foil duct tape, or manufacturer-specified sealants to ensure an airtight system. Grease filters are mandatory for any intake located within 3 meters of a cooktop.
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.