What feature must exit doors be equipped with for fire safety?

Exit doors are critical components in fire safety, and equipping them with automatic closing devices is essential. These devices ensure that doors close securely after use, preventing the spread of smoke and fire from one area to another. When a fire occurs, the immediate containment of the fire and smoke is crucial to protect occupants and allow for safe evacuation.

Automatic closing devices can also help maintain the integrity of fire-rated door assemblies, which are designed to withstand heat and smoke for a specified duration. This allows more time for occupants to escape and for emergency responders to manage the situation safely.

While other options may have their own relevance to safety and functionality, they do not specifically contribute to the primary fire safety objective of ensuring that exits close after being used, which is vital in preventing the spread of fire and smoke.