Ontario Building Code Practice Exam

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

1. Non-combustible materials

2. Labeled with a fire rating

3. Continuous from floor to underside of roof sheathing

4. Minimum thickness of 50 mm

The correct answer is: Minimum thickness of 50 mm

The three other options are essential components for a fire-rated wall assembly in a residential building. Non-combustible materials are necessary to prevent the spread of fire, a labeled fire rating ensures the wall has been tested and meets safety standards, and the wall must be continuous from floor to roof to contain a fire and prevent it from spreading. A minimum thickness requirement is not necessary for a fire-rated wall assembly. In fact, the thickness of a fire-rated wall may vary depending on the type and placement of insulation.