Lift Overrun Up Incident

Photo: Computer sketch on the lift overrun up incident

A lift breakdown call was received at midnight and a technician was dispatched immediately and upon arrival at site he noticed that the lift had over travelled at the highest floor and the lift counterweight struck the buffer. There was no injury or casualty resulting from the incident. At the moment of breakdown, the keypad inverter indicate undercurrent (LU) and overcurrent (OC1) readings. The lift has been in operation for approximately 6 years with a capacity of 17 persons (1160 kg) and contract speed of 1.75 meter per second (m/s).

Following this event, it is recommended that the following safety measures are taken:-

1. Brake replacement works must be carried out by highly trained personnel and strictly adheres to the procedures contained in the maintenance manual;
2. Thorough supervision must be carried out on any personnel involved in all brake replacement works to ensure that the brakes materials and components are selected according to the original specifications; compression brake springs are adjusted according to the correct compression value; and the brake torque test must be conducted after the completion of the brake replacement works;
3. Available lift breakdown records must be analyzed at regular intervals to determine the breakdown frequencies and immediately come out with suggestions of corrective actions to be implemented so as to reduce the rate of breakdown frequencies;
4. Formulate a more effective system to monitor and record in writing the brake pad thickness to take immediate action to replace the brake pad if the brake pad thickness has reduced to or approaching the minimum safe allowable thickness;
5. Ensure an effective procedure for brake contactor as stated in the manufacturer specification include the brake contactor inspections and testing during the monthly lift service;
6. During any maintenance works, inspections must carried out on all lift and counterweight buffers to ensure that the oil buffers are always refilled to its recommended level as stated in the lift maintenance manual;
7. Intensive trainings on lift breakdown or emergency responses must be constantly conducted to ensure that the lift technicians are always ready and equipped with the right knowledge so as to prevent any misplaced priorities. For example in the handling and securing the data logger. Such information are important for incident investigations and need to be handed over when requested by the relevant government authorities