Under which condition should fire doors be kept closed?

Fire doors are specifically designed to prevent the spread of fire and smoke between separate compartments within a building. They serve as a critical component of a building's overall fire protection strategy. When fire doors are kept closed, they create a barrier that limits the movement of flames and toxic smoke, which is essential for protecting occupants and allowing them safe escape routes during a fire incident.

While maintaining temperature, preventing dust intrusion, and controlling noise levels are valid considerations in some contexts, they do not focus on the primary purpose of fire doors. The fundamental role of these doors in fire safety underscores why they must be kept closed to effectively contain fires and minimize damage and risk to life. This is aligned with fire safety regulations and guidelines, reinforcing that the main reason for the existence of fire doors is to mitigate the spread of fire and smoke within buildings.