OBC 2024 Guide to Ramps, Stairways, and Exit Capacity Requirements in Ontario
Sarah's Expert Insight
OBC Compliance Specialist
"Navigating the complexities of exit capacities and stair geometry is critical for both urban commercial developments in London and Oakville and luxury residential retreats in Muskoka. As empcontracting.ca Inc. your construction contractor in London, Ontario, we ensure that every curved staircase and ramp profile meets these rigorous 2024 standards to avoid costly inspection delays and ensure maximum occupant safety."
Understanding the 2024 Building Code Compendium is essential for any major renovation or new build. As empcontracting.ca Inc. your construction contractor in London, Ontario, we prioritize compliance with Section 3.3.1 to ensure safety and accessibility in every project.
3.3.1.14 & 3.3.1.15: Ramps, Stairways, and Exterior Passageways
In general, ramps and stairways that are not designated as exits must still adhere to the strict requirements for exit facilities found in Section 3.4. This ensures a uniform level of safety throughout a building.
Exceptions for Industrial and Service Spaces
An exception is made for service rooms or industrial occupancies where stairs or ramps are intended only for occasional equipment servicing. In these specific cases, provided they do not serve as exits, the standard stringent requirements may be relaxed.
3.3.1.16: Tapered Treads and Curved Flights
The OBC 2024 provides clear geometric requirements for curved stairs to prevent trip hazards. Key dimensions include:
- Minimum Run: 150 mm at the narrow end.
- Run Measurement: At least 280 mm when measured 300 mm from the narrow end's handrail center line.
- Consistency: Tapered treads must maintain a consistent angle and uniform rise/run dimensions within a flight.
3.3.1.17: Calculating Access to Exit Capacity
The capacity of an access to exit is determined by the occupant load of the floor area. The code specifies minimum widths per person to ensure safe egress during emergencies:
Standard Capacity Measurements
- Standard Ramps, Doors, and Corridors: 6.1 mm per person.
- Steep Ramps (Slope > 1 in 8): 9.2 mm per person.
- Healthcare/Care Occupancies (Group B, Div 2 or 3): 18.4 mm per person.
Furthermore, in non-sprinklered buildings, the principal entrance for high-capacity assembly spaces like dance halls or licensed establishments (over 250 occupants) must provide at least half of the required exit width.
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.