Ontario Building Code Practice Exam

Which of the following is not a requirement for a fire-rated assembly in a commercial building?

1. Labeled with a fire rating

2. Minimum thickness of 75 mm

3. Continuous from floor to underside of roof sheathing

4. Minimum height of 2.4 meters

The correct answer is: Minimum thickness of 75 mm

Fire-rated assemblies in commercial buildings are required to meet certain safety standards to prevent the spread of fire. These requirements help protect the building and its occupants during a fire. Option A is correct because fire-rated assemblies must be clearly labeled with their fire rating. Option C is also correct because fire-rated assemblies must be continuous from the floor to the underside of the roof sheathing to prevent fire and smoke from spreading through any gaps or openings. Option D is also correct as fire-rated assemblies must reach a minimum height of 2.4 meters to provide a safe route for occupants to exit the building. Option B, however, is incorrect because there is no specific minimum thickness requirement for fire-rated assemblies. The thickness may vary depending on the materials used and the type of fire rating required for the assembly. Therefore, B is not a necessary requirement for a fire-rated assembly in a commercial building.