Which type of smoke detector sends elevators to a specific landing when activated?

Elevator lobby smoke detectors are specifically designed to play a crucial role in the safety of elevator systems during a fire incident. When smoke is detected, these detectors can communicate with the elevator control system, triggering the elevators to move to a predetermined landing, typically the ground floor or another safe area. This functionality is essential for ensuring the safety of individuals who may be using the elevators during an emergency, as it prevents them from being trapped in an elevator that could open on a floor where a fire is present.

Duct smoke detectors, while important for detecting smoke in the airflow of air conditioning ducts, do not have any control over elevators and primarily function to shut down HVAC systems to prevent smoke spread. Combination detectors integrate multiple sensing technologies but are not specifically focused on elevator operation in emergencies. Ionization smoke detectors are effective at detecting fast-burning fires but also lack the capability to influence elevator movement.

Thus, elevator lobby smoke detectors are uniquely tasked with both detecting smoke and coordinating the safe operation of elevators in an emergency, which is why they are the correct answer in this context.