OBC 5.9.3 Requirements for Curtain Walls and Storefronts | empcontracting.ca Inc.
Sarah's Expert Insight
OBC Compliance Specialist
"As a senior consultant at empcontracting.ca Inc., your construction contractor in London, Ontario, I emphasize that thermal break integration in curtain walls is non-negotiable for mitigating condensation during our harsh Southwestern Ontario winters. Whether we are retrofitting a storefront in Oakville or installing a window wall in a Muskoka cottage, adhering to the 0.2 L/(s·m²) air leakage standard for fixed glazing is the key to preventing energy loss and ensuring long-term structural durability."
Navigating the 2024 Ontario Building Code (OBC) is essential for any commercial or high-end residential build. At empcontracting.ca Inc. your construction contractor in London, Ontario, we specialize in ensuring your building envelope meets the rigorous standards of Part 5 regarding 'Other Fenestration Assemblies.'
Defining Other Fenestration Assemblies (OBC 5.9.3.1)
Under Subsection 5.9.3, the term "other fenestration assemblies" specifically refers to high-performance architectural elements including:
- Curtain walls
- Window walls
- Storefronts
- Glazed architectural structures
Structural Performance and Environmental Loads
According to Article 5.9.3.2, all fenestration assemblies must be designed to withstand structural and environmental loads in accordance with Article 5.1.4.1. This ensures that glazed structures can withstand wind loads and environmental pressures specific to the Ontario climate.
Heat Transfer and Thermal Integrity (OBC 5.9.3.3)
Thermal performance is critical for energy efficiency and occupant comfort. The OBC mandates that:
- Assemblies meet the heat transfer requirements stated in Section 5.3.
- Thermal Breaks: Metal-framed assemblies separating conditioned space from the exterior must incorporate a thermal break to minimize condensation, a vital feature for the cold winters in London and Muskoka.
Air Leakage and Water Penetration Standards
To maintain a tight building envelope, the OBC sets strict limits on air leakage (ASTM E283) at a pressure difference of 75 Pa:
- Fixed Portions: Maximum leakage of 0.2 L/(s·m²)
- Operable Portions: Maximum leakage of 1.5 L/(s·m²)
Exceptions to Air Leakage Testing
Per Article 5.9.3.4.(3), certain systems are exempt from these specific air leakage rates, including vehicular access doors, revolving doors, commercial entrance systems, and smoke vents. However, all assemblies must still comply with Section 5.6 for water penetration resistance (OBC 5.9.3.5).
For expert implementation of these codes, trust empcontracting.ca Inc. your construction contractor in London, Ontario, to manage your next glazed architectural project.
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.