Elevator Door Nudging: Timeout Hold-Open, Reduced Speed, Buzzer Warning and EN 81-20 4 J Kinetic Energy Limit

Nudging (also called buzzer operation or reduced-speed close) is a time-out mechanism designed to prevent an elevator door from being held indefinitely open, which would stall service for other passengers. Operation sequence: (1) Passenger holds door open (e.g. blocking light curtain) or door safety edge is continuously activated; (2) After a defined dwell time (typically 20–45 seconds, set in the controller), the controller enters nudging mode; (3) Doors start to close at reduced speed (typically 50–75% of normal closing speed); (4) A buzzer or audible warning sounds continuously during the nudge close; (5) The door safety edge or light curtain signal is ignored during the nudge sequence (i.e. the door will not re-open even if the safety edge is triggered). The rationale: nudging forces doors closed after unreasonable holding but at low speed to minimise injury risk. EN 81-20 permits nudging but specifies that the reduced closing speed must limit kinetic energy at the door leading edge to ≤4 J. The nudge speed must therefore be calculated based on the door mass to ensure compliance. Nudging is particularly important for heavily-trafficked floors and hospital elevators. It must not activate during the initial door opening phase.

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