Ontario Building Code Practice Exam

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

1. Labeled with a fire rating

2. Non-combustible framing

3. Minimum thickness of 6 mm

4. Continuous from floor to underside of roof sheathing

The correct answer is: Minimum thickness of 6 mm

A minimum thickness of 6 mm is not a requirement for a fire-rated window assembly in a residential building because the other options are more important factors that contribute to the fire resistance of the window. A fire-rated window must be labeled with a fire rating, have a non-combustible framing material, and be continuous from the floor to the underside of the roof sheathing. These features help to prevent the spread of fire and protect occupants in the event of a fire. Choosing a thicker window does not necessarily guarantee better fire resistance, as it depends on the overall construction and materials used.