Hazard Alert Follows Two Severe Injuries Involving Demolition Robots
It recommends preparing a job hazard analysis with operators for each new job to identify and control hazards and using the manufacturer's safety instructions to establish the risk zone for the specific machine, attachment, and task.
The Washington State Department of Labor & Industries has published a Hazard Alert about two severe injuries suffered by workers who were operating remote-controlled demolition machines, also known as demolition robots.
One worker was a specialty trade contractor using a machine fitted with a shear attachment to demolish an HVAC system. According to the alert, the worker was wearing a waist-mounted remote controller attached to the machine by a wire. He repositioned the machine and then had to move the power cable before extending the outrigger. In the process he accidentally bumped the remote control against the machine, which moved and pinned him between the outrigger and a wall. He tried to free himself but lost consciousness. Co-workers had to cut power to the machine and try to push it over with a skid steer. The worker's chest was severely crushed, causing him to miss work for several months.
The second case described in the alert involved the operator of a machine fitted with a breaker attachment to chip concrete during a generator installation project. The operator was standing in a tight location between the machine and an excavation wall; as he tried to apply more pressure on the tip of the breaker, the outrigger raised off the ground, and then the machine shifted forward and the outrigger came down, crushing the operator's foot.
The alert says the employer in this latter case conducted a JHA that identified the swing radius of the machine's arm as a hazard but did not recognize the potential of being crushed under the outrigger. However, the manufacturer's safety instructions warned never to stand where there is a risk of being crushed.
The alert makes these recommendations:
- Prepare a job hazard analysis with operators for each new job to identify and control hazards. Use the manufacturer's safety instructions to establish the risk zone for the specific machine, attachment, and task.
- Always stay outside the risk zone when the machine is in operation and do not enter until the machine is put into emergency stop mode or de-energized.
- Consider using a proximity warning system, such as those based on radio frequency identification (RFID), to maintain a safe worker-to-machine distance.
- Train operators to manage power cables and to continually monitor the process for hazards and redefine the risk zone.
- Ensure operators always read and follow manufacturer’s provided safety instructions.
- Consider using a spotter to assist the operator.