OBC 2024 Ventilation & Ducting Requirements: Expert Guide by empcontracting.ca Inc. your construction contractor in London, Ontario
Sarah's Expert Insight
OBC Compliance Specialist
"Properly balancing return-air pressure and exhaust rates is the most overlooked aspect of HVAC compliance in London and Oakville renovations. By partnering with empcontracting.ca Inc. your construction contractor in London, Ontario, you ensure your project avoids the common pitfalls of improper plenum placement and combustion air interference, keeping your build both safe and OBC-compliant."
Section 6.3.2.10: Exhaust Air and Ventilation Rates
The 2024 Ontario Building Code (OBC) mandates precise exhaust air rates to maintain indoor air quality and moisture control. For standard fixtures including water closets, showers, and slop sinks, the exhaust rate must be at least 24 L/s. For residential dwelling units, the code points to ANSI/ASHRAE 62.1 standards. At empcontracting.ca Inc. your construction contractor in London, Ontario, we ensure that food premises are equipped with mechanical ventilation capable of meeting these 24 L/s requirements for every sanitary fixture involved.
Section 6.3.2.11: Return-Air System Regulations
Safety and Plenum Placement
Return-air systems are governed by strict safety protocols to prevent the spread of fire and the backdrafting of toxic gases. Key requirements include:
- Public corridors and exits must never be used as return-air plenums.
- The system must be engineered to manage the entire air supply volume.
- Negative pressure from circulating fans must not interfere with combustion air for fuel-fired appliances.
Section 6.3.2.12 - 6.3.2.14: Ductwork and Filtration Standards
Underground Ducting Protocols
Underground ducts require specialized construction to prevent moisture buildup and contamination. They must provide interior drainage, include clean-outs at every low point, and utilize materials recommended by ASHRAE and SMACNA standards. Connection to sewers is strictly prohibited.
Air Filter and Cleaning Specifications
To ensure fire safety, air filters must meet Class 2 requirements under CAN/ULC-S111. Electrostatic filters require automatic de-energizing switches to protect occupants and maintenance staff. These technical details are vital for commercial and residential compliance in Southwestern Ontario.
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.