Frequently Asked Questions — Elevator Emergency Power Systems (ARD)
Is an ARD (Automatic Rescue Device) mandatory for all elevators?
EN 81-20 (clause 12.10) requires provision for releasing trapped passengers from the elevator car, but the specific implementation — ARD, manual rescue operation, or alternative means — depends on the applicable national regulation and the building's risk assessment. In Turkey and across the EU, ARD is strongly recommended for all passenger elevators and is mandatory in buildings where manual rescue by trained personnel cannot be guaranteed within an acceptable timeframe (typically 30 minutes). Hospital, high-rise, and public buildings commonly require ARD by regulatory authority.
How does an ARD system work?
On detection of a mains power failure, the ARD unit switches the elevator drive from AC mains supply to its internal battery bank. The system then drives the car at reduced speed (typically 0.1–0.3 m/s) to the nearest floor in the optimal direction based on car position and battery state of charge. On reaching the landing, the doors are opened, passengers exit, and the doors close before the system powers down. The entire sequence is automatic and requires no intervention from building personnel.
What battery technology is used in modern ARD units?
Most modern ARD systems use sealed VRLA (valve-regulated lead-acid) or lithium-ion battery packs. VRLA batteries offer proven reliability and lower cost; lithium-ion units provide a longer cycle life (typically 5–8 years vs. 3–5 years for VRLA), faster recharge, and a smaller footprint at higher cost. Battery health is monitored by the ARD's management system, which alerts service personnel when charge capacity drops below acceptable thresholds.
Can an ARD be added to an existing elevator during modernization?
Yes — ARD retrofit is one of the most common modernization additions, particularly for elevators that pre-date the mandatory introduction of automatic rescue requirements. The ARD unit must be compatible with the existing VFD (typically connected to the DC bus or the motor terminals) and correctly integrated with the elevator controller's fault detection logic. Turkish suppliers on elevator.tr provide compatibility assessments and commissioning support for retrofit installations.