What fire resistance rating must a ceiling have to maintain vertical continuity for a 1-hour-rated fire barrier wall assembly?

A ceiling must have a fire resistance rating that matches or exceeds that of the fire barrier wall assembly to maintain vertical continuity. In this case, since the fire barrier wall assembly is rated for 1 hour, the ceiling must also have a fire resistance rating of at least 1 hour. This ensures that the integrity of the fire barrier is maintained, preventing the passage of smoke and flames through the ceiling in the event of a fire, thereby effectively continuing the protection intended by the fire barrier wall.

If the ceiling had a lower rating, such as ½ hour, it would not adequately support the objectives of the fire barrier during a fire scenario, potentially compromising safety. Similarly, ceilings rated for 2 hour or 3 hour resistance would exceed the necessary rating and may not be required, but they can still provide additional safety margins. However, the minimum requirement to ensure that the fire barrier's purpose is fulfilled is the 1-hour rating, aligning with the fire barrier wall assembly.