What is the minimum number of fire alarm control circuits for Phase I recall for each group of elevators?

What is the minimum number of fire alarm control circuits for Phase I recall for each group of elevators?

• A. 1
• B. 2
• C. 3
• D. 4

Answer: (C)

Phase I recall relies on reliable signaling to move elevators to a safe floor and keep them under firefighter control during a fire. To avoid a single point of failure taking down recall, the system uses multiple independent signaling paths from the fire alarm control to each elevator group. The minimum is three independent fire alarm control circuits for a group. One circuit initiates the Phase I recall to the elevator group, another provides ongoing supervision/monitoring of that recall path, and the third supports the Firefighter’s service function and status indication. With three separate circuits, if one path is compromised, the other two can still carry the recall and maintain safe elevator operation.

Phase I recall relies on reliable signaling to move elevators to a safe floor and keep them under firefighter control during a fire. To avoid a single point of failure taking down recall, the system uses multiple independent signaling paths from the fire alarm control to each elevator group. The minimum is three independent fire alarm control circuits for a group. One circuit initiates the Phase I recall to the elevator group, another provides ongoing supervision/monitoring of that recall path, and the third supports the Firefighter’s service function and status indication. With three separate circuits, if one path is compromised, the other two can still carry the recall and maintain safe elevator operation.