21.3.5* A lobby smoke detector shall be located on the ceiling within 21 It (6.4 m) of the centerline of each elevator door within the elevator bank under control of the detector.
21.3.3 Unless otherwise required by the authority having jurisdiction, only the elevator lobby, elevator hoistway, and elevator machine room smoke detectors, or other automatic fire detection …… shall be used to recall elevators for fire fighters’ service.
The objective behind requiring smoke detection in front of each elevator door is to initiate elevator phase I recall operation in the event that there is a fire within the vicinity of the elevator doors. The elevator shall immediately recall to a safe lobby location to allow passengers to exit the elevator, and allow responding emergency personnel (Fire Department) to use the elevator via Phase II operation.
