What must be done to ensure fire doors function correctly?

Ensuring that fire doors function correctly is crucial for maintaining safety in a building. Fire doors are designed to prevent the spread of fire and smoke between different areas, thus protecting escape routes and giving people more time to evacuate. For fire doors to adequately perform this essential function, they must be self-closing. This means that they close automatically after being opened, ensuring no gap is left for smoke or flames to escape through. Additionally, fire doors should never be blocked, as this hinders their operation and could result in a dangerous situation during a fire emergency.

By keeping fire doors self-closing and unobstructed, they serve their primary purpose effectively, contributing to the overall safety of the building's occupants. Other options do not address the operational requirements that ensure a fire door performs its intended life-saving function.