Safety is paramount in revolving door design due to the rotating assembly and potential for collision with users. Modern revolving doors incorporate multiple layered safety sensor systems that detect users and prevent collisions. This article explains the various safety technologies employed.
1. Presence Detection Sensors
Microwave motion sensors mounted in the enclosure header detect pedestrians approaching from outside before they enter the door threshold. These sensors trigger door speed adjustment or prevent the door from accelerating when someone is still in the passage compartment. Detection zones are carefully programmed to distinguish between pedestrians approaching the door and background traffic on adjacent sidewalks to prevent false triggers.
2. Compartment Presence Sensors
Infrared sensors mounted inside the enclosure detect the presence of users within each passage compartment. These sensors prevent the wing from accelerating or starting rotation when a user is still occupying the compartment. They also detect users who may have stopped inside the door due to confusion or difficulty, triggering audio or visual alerts to encourage completion of passage.
3. Wing Leading Edge Safety Sensors
Pressure-sensitive safety edges mounted on the leading edge of each wing detect contact with obstacles or users. Upon detection, the drive system immediately reverses rotation direction to prevent crushing or shearing injuries. Sensitivity calibration ensures detection of small obstacles while preventing false triggers from normal user contact with the wing surface during passage.
4. Speed Monitoring and Anomaly Detection
Electronic controllers monitor rotation speed through encoder feedback from the motor. Sudden speed changes indicate abnormal loading from wing collision or user contact with the rotating assembly. The controller responds by stopping rotation and triggering alert signals for facility management attention. Some systems include audio warnings to alert nearby users of the abnormal condition.
5. Emergency Stop Controls
Emergency stop buttons positioned at accessible heights near the door allow users to immediately halt rotation if safety concerns arise. Activation triggers immediate drive motor shutdown and application of holding brakes to prevent door coasting. Stop buttons must be clearly marked, unobstructed, and reachable by mobility device users. Reset requires deliberate action by trained facility staff to prevent immediate restart that could startle nearby users.
This article compiles information from publicly available automatic door industry resources.