Workplace Health and Safety Queensland recently issued a safety alert following an incident in which a worker was killed while operating an industrial shredding machine used to process bulk waste building materials.
Initial enquiries indicate he was attempting to remove a blockage from the shredding machine, and investigations are continuing and include scrutiny as to why the machine became operational.
The alert said fixed plant, including industrial shredding machines, often have several different types of moving parts and hazards associated with fixed plant include:
- rotating shafts, pulleys, gearing, cables, sprockets, or chains
- belt run-on points, chains, or cables
- crushing or shearing points such as roller feeds and conveyor feeds
- machine components that process and handle materials or product (i.e. move, flatten, level, cut, grind, pulp, crush, break or pulverise materials)
- unexpected movement of parts operated by hydraulic, electrical, electronic or remote control systems.
Workers performing tasks such as maintenance, repair, installation, service and cleaning on machines in all industry sectors are highly vulnerable and have a higher risk of being seriously injured or killed through inadvertent operation of machinery and equipment they are working in, on, or around.
The alert said effective control measures for machinery are often made up of a combination of controls. Some common risk control measures can include but are not limited to the following examples.
Engineering controls include modifications to tools or equipment. Examples of engineering controls include:
- Guarding – physical or other barriers that increase safety for operators and others involved in the normal operation, servicing, and maintenance of machines. Types of guarding:
- a permanently fixed guard if access to parts of the plant is not necessary during operation, maintenance, or cleaning (for example, distance guards on a feed chute)
- an interlock guard is connected to the plant’s operating controls so the plant can’t operate when the guard is open. The guard should not be able to open or be removed until the moving parts (i.e. cutting blade) have stopped. Similarly, when an interlocked guard is re-closed, the machine should not automatically restart
- a fixed guard, which can only be altered or removed with a tool not normally available to the machine operator
- a presence sensing system which detects when a person (or part of a person’s body) enters the danger zone and stops a machine. Photoelectric light beams, laser scanners and foot pressure mats are examples of these type of guards. They rely on sensitive trip mechanisms and the machine being able to stop quickly.
- Providing suitable tools to prevent the need for workers to enter the danger zone for clearing blockages.
- Installing mechanical locks to support parts suspended by hydraulic systems.
- Locking out remote controls to ensure they cannot be activated when the worker is in the danger zone.
Risks can be further minimised by implementing administrative and personal protective equipment (PPE) controls. Examples include:
- installing a lock out/tag-out system to ensure the plant is isolated from its power source and cannot be operated while clearing blockages, performing maintenance or cleaning work prior to accessing any parts of the machine
- providing information, training, instruction, and supervision to workers who will use the plant that includes the development of safe work procedures in accordance with the manufacturer’s instructions
- consulting workers to obtain feedback on the plant and associated work processes and safe work procedures
- hard hats, gloves, protective footwear, eye protection, hearing protection, and high visibility clothing.
AIHS | Australian Institute of Health & Safety
February 21, 2021