Understanding Fire Block Requirements: 2024 Ontario Building Code (OBC) Section 9.10.16
Sarah's Expert Insight
OBC Compliance Specialist
"In rapidly developing areas like London and Oakville, municipal inspectors are increasingly strict regarding fire blocking in finished basements and custom builds. As empcontracting.ca Inc. your construction contractor in London, Ontario, we emphasize that proper fire blocking is not just a code requirement—it's a vital life-safety component that provides occupants the necessary time to evacuate during a fire."
Fire safety is a cornerstone of the 2024 Ontario Building Code (OBC), specifically regarding the prevention of fire spread through concealed spaces. At empcontracting.ca Inc. your construction contractor in London, Ontario, we prioritize these life-safety measures in every residential and commercial project.
Required Locations for Fire Blocks (9.10.16.2)
Fire blocks are essential barriers designed to restrict the movement of flame and hot gases within hidden areas of a building. According to Section 9.10.16.2, fire blocks must be installed within wall assemblies and spaces created by furring at the following intervals:
- Floor and Ceiling Levels: At each floor level and at ceiling levels where the ceiling is part of a required fire-resistance rating.
- Horizontal and Vertical Spacing: At intervals not exceeding 20 meters horizontally and 3 meters vertically.
Exceptions to Wall Assembly Fire Blocking
Fire blocks may be omitted if the wall assembly meets specific criteria, such as being filled entirely with insulation, containing only noncombustible materials, or having a flame-spread rating of 25 or less.
Fire Blocks in Concealed Spaces and Roofs
The code also mandates fire blocking in horizontal interconnections, such as:
- Coved and Drop Ceilings: Where construction materials have a flame-spread rating greater than 25.
- Stairwells: At the top and bottom of each run of stairs passing through a floor with concealed spaces.
- Attic and Roof Spaces: In unsprinklered combustible roof spaces, compartments must be limited to 60 meters in the greatest dimension to prevent unchecked fire travel.
Approved Fire Block Materials (9.10.16.3)
Performance Standards
Materials used for fire blocking must be capable of remaining in place and preventing the passage of flames for at least 15 minutes when tested against CAN/ULC-S101 standards.
Deemed-to-Comply Materials
The OBC lists several common materials that are automatically deemed to meet the 15-minute requirement:
- 0.38 mm sheet steel
- 12.7 mm gypsum board
- 12.5 mm plywood, OSB, or waferboard (with supported joints)
- 38 mm lumber or two layers of 19 mm lumber with staggered joints
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.