Smoke detectors used for recalling an elevator for fire fighters' service must be what?

The requirement that smoke detectors used for recalling an elevator for firefighter service must be connected to the building fire alarm system is essential for ensuring that the system functions effectively during an emergency. This connection allows for immediate communication between the smoke detectors and the fire alarm system, ensuring that when smoke is detected, the elevator can be recalled to a designated landing, typically the ground floor. This feature is critical for facilitating safe evacuation and access for firefighters.

In addition, the detectors must meet specific standards and be appropriately rated for elevator recall service, and also receive approval from the Authority Having Jurisdiction (AHJ). These requirements ensure that all components work seamlessly and comply with fire safety regulations. However, the primary requirement tied to the recall function itself is that the smoke detectors are integrated into the fire alarm system, enabling a coordinated response in emergencies.