What is the maximum transmitted temperature rise for fire door assemblies in interior exit stairways after 30 minutes of standard fire test exposure?

Fire door assemblies are critical for maintaining the safety and integrity of interior exit stairways in the event of a fire. These assemblies must be designed to limit the transfer of heat to adjacent spaces to ensure safe passage for occupants during an emergency evacuation.

In a standard fire test, after 30 minutes of exposure to fire conditions, the maximum allowable transmitted temperature rise is determined to establish that the door remains functional and continues to provide a barrier against the spread of fire and smoke. The National Fire Protection Association (NFPA) and other relevant codes define this maximum temperature rise to ensure safety.

The correct answer indicates that after 30 minutes of testing, the maximum temperature rise that can be transmitted through a fire door assembly is 450°F. This temperature threshold is established to ensure that the door provides adequate protection while also allowing time for occupants to escape safely. Exceeding this temperature could compromise the integrity of the door and its ability to serve as a barrier, resulting in unsafe conditions.

Understanding this maximum transmitted temperature rise is crucial for building inspectors as it informs them about compliance issues related to fire safety standards in commercial buildings. Awareness of these parameters helps ensure that fire door installations are effective in protecting occupants and maintaining safe egress routes during a fire incident.