For a wall with a fire-resistance rating of 30 minutes, what should the door assembly be rated?

For a wall that has a fire-resistance rating of 30 minutes, the door assembly should typically match or exceed the fire-resistance rating of the wall to maintain the overall integrity of the fire barrier. A door assembly with a fire-resistance rating of 20 minutes would not adequately provide the same level of protection and could create a vulnerability in the fire barrier.

In most building codes and regulations, including those referenced in the NCIDQ exams, it is common practice for the door rating to equal or exceed that of the wall it serves. Therefore, a door assembly rated for 30 minutes is appropriate, as it would provide continuity and ensure that the intended fire protection is not compromised. A door with a rating of 20 minutes does not fulfill the requirement established by the fire-resistive characteristics of the wall.

This principle ensures that fire barriers function as designed, preventing the spread of fire and smoke for the designated period. Having an under-rated door assembly could cause significant safety issues, as it could fail to contain a fire within the partition. Thus, the fire-resistance rating of the door assembly is a critical aspect that needs to align with the walls in order to meet safety codes and effective fire protection standards.