What is the main function of fire doors?

The main function of fire doors is to resist the passage of smoke and flames. Fire doors are specifically designed to act as a barrier that prevents the spread of fire and smoke between different sections of a building. They are an essential component of a building's passive fire protection system, which aims to contain fires and limit their impact, thereby enhancing the overall safety of the structure and its occupants.

In the event of a fire, fire doors help to maintain safe egress routes for occupants by confining the fire to a specific area, which also allows more time for evacuation and reduces the risk of injury. The effectiveness of fire doors is dictated by their construction, which often includes materials that can withstand high temperatures and prevent smoke infiltration, thereby providing a critical safety feature during emergencies.

Other options, while relevant in different contexts, do not capture the primary purpose of fire doors as effectively. Noise reduction, energy efficiency, and access to emergency exits are not the main functions of fire doors, though they could relate to other building design features or systems.