Ontario Building Code Practice Exam

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

1. Non-combustible materials

2. Labeled with a fire rating

3. Continuous from wall to wall

4. Minimum thickness of 50 mm

The correct answer is: Minimum thickness of 50 mm

A minimum thickness of 50 mm is not a requirement for a fire-rated ceiling assembly in a residential building. The other options, non-combustible materials, labeled with a fire rating, and continuous from wall to wall, are all necessary for a fire-rated ceiling assembly. Non-combustible materials ensure that the ceiling will not catch fire easily, while being labeled with a fire rating allows for easy identification of the level of protection provided. A continuous ceiling from wall to wall helps prevent the spread of fire and smoke. A minimum thickness of 50 mm is not a requirement as long as the other elements are present and meet the necessary fire safety standards.