What is a requirement for all fire doors?

A fire door must be self-closing to meet safety standards and effectively limit the spread of fire and smoke within a building. The self-closing feature ensures that the door closes automatically after being opened, which is crucial in maintaining the integrity of fire-rated barriers. This mechanism helps to contain the fire within the designated area until it can be extinguished, thereby protecting occupants and allowing for safer evacuation routes.

While the fire-resistant quality of a door is also important, it alone is not sufficient if the door does not close securely. Self-closing doors ensure compliance with building codes that are designed to enhance fire safety. Other options, such as double hung or masonry, do not represent essential requirements for fire doors, as they pertain to different types of construction or door styles that do not influence a door's ability to function effectively in a fire situation.