Which rating corresponds to a door assembly for a wall with a fire-resistance rating of 1 hour?

For a door assembly that is part of a wall with a fire-resistance rating of 1 hour, the appropriate rating for the door itself must match or be equal to the fire-rating of the wall. This means that if a wall has a fire-resistance rating of 1 hour, the door assembly installed in that wall should ideally also have a fire-resistance rating of 1 hour.

By this reasoning, the correct choice of 1 hour indicates that the door assembly is designed to provide the same level of protection against the spread of fire as the wall, ensuring that it can withstand the conditions of a fire for the same amount of time. This alignment is crucial for maintaining the integrity of fire-rated assemblies and for ensuring safety and compliance with building codes.

A fire rating lower than 1 hour, such as 20 minutes, 30 minutes, or 45 minutes, would not provide adequate protection in a scenario where the wall itself is rated for 1 hour. Therefore, such options are not suitable for a door assembly that needs to match the 1-hour fire-resistance rating of the wall.