Accidents with manlifts

Lessons from Losses 7/2010. During the recent years, there have been quite a lot of fatal accidents with manlifts such as cherry pickers, scissor lifts and boom lifts. These accidents are due to negligence regarding safety measures and the improper use of lifts. This Lessons from losses describes some of these accidents and gives hints and instructions for the safe use of manlifts.

Case 1

Worker got squeezed between the guard rail of a lift and the structure above.

What happened?

Two workers were working in the basket of a scissor lift. One of them got down to go for lunch. The other stayed in the basket to move the lift one meter to the next work station. The worker going to lunch looked back and saw that the lift was going up. He did not see the actual accident, but the head of the worker in the basket got squeezed between the guard rail and the structure above.

When the other worker realized the situation, he climbed up into the basket. However, he was unable to lower it down because the injured worker was squeezed against the lifts control panel. There is an emergency release wire at the base of the lift, which lowers the basket all the way down, but the worker was not aware of its existence. The fire department found the wire when they came and the injured worker was released. Unfortunately the worker died as a result of his injuries.

What caused the accident?

Was the lift appropriate for the task?

  • Considering the workplace, the lift was too big and too fast. This size of the lift was inadequate for such a relatively small place.
  • At that height, when the lifts engine is cold, the basket moves up with a slight delay and at least 20 cm at a time.

The worker made an error while moving the lift. The logic of the controls makes a human error easy to occur.

  • The controls for operating the lift are designed so that driving around and moving the basket up and down are controlled with the same joystick. The function between these two is selected from a separate switch.
  • For some reason, the injured worker lifted the basket up before driving the lift to the next work station one meter ahead. Apparently he leaned out of the basket to see the tires of the lift while driving. The accident occurred because he forgot to turn the switch to driving position. Instead of going forward, the basket bounced up squeezing the workers head between the lifts protective fence and the structure above.
  • The other worker did not know how to lower the basket down. He wasn’t aware of the emergency release wire.

Case 2

A worker was lifting himself with a scissor lift to fit a 50 kg beam to its final position. He needed both hands to hold the beam so he used the control of the lift with his elbow. For unknown reasons he was unable to stop the lift and got squeezed between the guard rail of the lift and the roof above. He died of his injuries.

Apparently the worker was in a hurry and did not want to wait for help. This accident would have been avoided had there been a co-worker operating the lift.

Case 3

Two workers fell down from the basket of a boom lift installed to a truck. One support leg of the truck was over an old coal hatch covered with asphalt. The surface under the leg collapsed, the basket hit the building and the workers fell down from 10 m and died.

In this case it was almost impossible for the workers to identify the old coal hatch, but the case emphasises well the need to check the quality of the surface below the lift. Also the use of safety harness in the basket would most probably have prevented the fatality of this accident.

Preventing similar accidents

Selecting an adequate lift for the job

  • Work tasks including manlifts should be planned beforehand. One should select an adequate lift for the task and working area. For example the available space (or the lack of it), needed height, requirements for moving the lift, other traffic and the quality of the surface should be taken into consideration.
  • Supervisors are responsible for ensuring that the users of the lift are properly trained to operate it and aware of the safety features.

Improving the logic and ergonomics of the controls

  • There should be separate switches for driving the lift and moving it up and down
  • The controls that operate the movement of the lift should be designed so that the principles of ergonomic and logical use are taken into consideration. A logical way to move the lift up and down is for example a joystick that moves up and down or two buttons that are indicated with up and down arrows.
  • The emergency release wire must be clearly indicated and always accessible.

Training and competence of the workers

  • Since 1.1.2009 the driver (person operating the lift) of a manlift must have a written permit admitted by his or her employer.
  • Before admitting the permit, the employer must insure that the worker is competent to use the lift.
  • The lifts should never be used alone. There should be another worker who can take control of the lift in an emergency situation. Preferably – and especially in limited work spaces – there should be one person to operate the lift and another to do the actual work.
  • Persons in a man lift basket should always wear a safety harness connected to the basket.

Daily checks must be done

  • Manlifts should be checked daily before use in case of possible faults including testing of controls and emergency equipment.
  • In addition, the condition and qualities of the surface below must be checked before using the lift.

Coordination and scheduling of the tasks

  • Tasks should be scheduled so that the need for manlifts is minimized.

Ville Niemelä