2024 Ontario Building Code Hazard Index: Group A and B Occupancy Guide
Sarah's Expert Insight
OBC Compliance Specialist
"When upgrading recreational grandstands in Muskoka or retrofitting institutional spaces in London, the Hazard Index is the pivot point for your entire budget. Under Part 11, a jump in H.I. often triggers mandatory fire-safety upgrades that can be costly if not identified during the feasibility phase. As the lead at empcontracting.ca Inc. your construction contractor in London, Ontario, I recommend a preliminary code audit to ensure these H.I. ratings align with your project’s occupancy goals."
Navigating the 2024 Ontario Building Code (OBC) is a critical step for any renovation or change-of-use project. At empcontracting.ca Inc. your construction contractor in London, Ontario, we prioritize compliance to ensure the safety and longevity of your investment.
Table 11.2.1.1.-E: Hazard Index for Assembly Occupancies (Group A, Division 4)
This table outlines the Hazard Index (H.I.) for open-air assembly structures. The H.I. is determined by the size of the building, which is categorized as Small, Medium, or Large based on occupant load and street access.
Key Ratings for Outdoor Assembly
- Amusement Park Structures: Hazard Index ranges from 2 (Small) to 5 (Large).
- Bleachers, Grandstands, and Stadia: Ratings start at 1 for Small facilities and reach 5 for Large facilities.
- Building Size Criteria: Small buildings are limited to 2,500 occupants with a 6m limiting distance; Large buildings allow for an unlimited occupant load.
Table 11.2.1.1.-F: Hazard Index for Care, Treatment, or Detention (Group B, Division 1)
Occupancies involving detention or restrained movement carry higher risk factors. The OBC applies stricter Hazard Index ratings to these facilities to account for evacuation challenges.
Detention and Security Classifications
- Minimum Security Detention: Hazard Index ranges from 4 to 6.
- All Other Security Types: Higher risk profile with ratings between 6 and 7.
- Police Stations with Detention: Specifically rated at 3 for small-scale facilities.
Understanding these ratings is essential when calculating the required fire separations and structural upgrades mandated by Part 11 of the OBC. If you are planning a change of use for an existing structure, empcontracting.ca Inc. your construction contractor in London, Ontario, provides the technical expertise to guide you through the permitting process.
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.