Angle grinders are one of the most dangerous tools in any workplace. They are used for cutting, grinding and polishing work.
Most angle grinder injuries are from metal particles lodging in the operator’s eye. However, the most serious injuries are from kick-back, where the disc is thrust back violently towards the operator.
Angle grinders used with cutting discs expose workers to a range of severe additional hazards. Discs can shatter or explode, sending pieces flying in all directions.
When intending to use an angle grinder, focus on the hazards and risks that could arise and put in place the necessary control measures. Elimination of the hazards or substitution with safer equipment should always be the first option.
Where a safer alternative cutting tool is available or can be obtained, an angle grinder should not be used as a cutting tool.
Whose responsibility is safety?
Employers have a responsibility to provide and maintain a safe working environment, as far as practicable, and safe work procedures for angle grinder use.
The employer must also provide information, instruction, training and supervision to enable employees to work safely with angle grinders.
Employees must follow any instruction and training provided, and must point out hazards to their supervisor. Employees also have a responsibility to take reasonable care to ensure their own safety and health, and to avoid affecting the safety or health of others.
People who supply angle grinders for hire should ensure that, as far as practicable, the tools do not, when used properly, expose the hirers to hazards. Hirers have an obligation under the Occupational Safety and Health Act 1984 to take all reasonable steps to ensure appropriate information about the safe use of angle grinders is available.
Use of other tools for cutting
Employers should provide purpose-designed cutting tools, for example drop saws, for materials like concrete, masonry, metal, ceramics, stone or plastic, so that there is no need for an employee to use an angle grinder for cutting.
Employees required to use angle grinders must be fully informed of the hazards, and instructed in safe work procedures. Safe work procedures should include avoiding, where practicable, the use of angle grinders for cutting.
Safe work procedures
The employer must provide safe procedures for angle grinder task and every employee who will use an angle grinder must receive training and instruction in these.
Safe work procedures should be developed in consultation with employees and safety and health representatives (if any).
Tasks using an angle grinder should not be allowed unless there is an agreed safe work procedure.
The basic requirements for angle grinder safety at the workplace include providing:
- information and training, including the manufacturer’s safety instructions, to all workers who will use angle grinders.
- safe work procedures specific to tasks to all operators.
- one-on-one supervision for people being trained and those who are unfamiliar with the use of angle grinders.
- general supervision for all angle grinding tasks.
In developing the safe work procedures, questions to ask include:
- is the grinding work necessary or could a different tool be used with less risk?
- is the correct size of grinder used for the job? Is there a risk of losing control of a heavier, more powerful tool? Could a smaller model be used for some or all of the work?
- does the guard cover half the disc between the operator and the disc?
- is the correct disc used for the job, depending on the type of material being worked on and the size of the disc?
- does the grinder have an automatic cut off or ‘deadman’ switch as part of the handgrip, cutting off the power as soon as finger pressure is released? This may not be necessary for certain tasks with smaller mode.
In addition, does your workplace have safe work procedures that ensure all operators:
- allow the grinder to ‘run up’ to operating speed before applying it to the job?
- know they must not remove the guard or handles from an angle grinder?
- use two hands to operate an angle grinder, including small models?
- hold the grinder against the work piece with minimum pressure, so the disc does not ‘dig in’ and cause it to kick back?
- never bump the grinder on to the job, or let the disc hit any other object while grinding?
- keep the grinding disc at a 15 to 30 degree angle to the work?
- make sure the work piece is held firmly in a bench vice, where necessary?
- keep the work at waist height during grinding, where possible?
- adopt a comfortable stance, with feet apart and well balanced, and with a clear view of the job?
- wear kneepads if work at floor level cannot be avoided?
- never use a grinder between the legs while sitting on the floor?
- stop the grinder at regular intervals for a short break to rest your hands and arms?
- disconnect the power and place the grinder on a bench with the disc facing upwards when not in use?
- never put a grinder down until the disc stops rotating?
- remove the plug from the power point before changing discs?
- never use a cut off wheel for grinding or a grinding disc for cutting?
Is the operator trained to check, before each use, that:
- the correct type of disc is being used?
- the guard and handles are secure?
- the correct flange and locking nut is in place for the type of disc being used? Otherwise the disc can shatter at high speed.
- there are no defects or damage to the disc?
- any disc that has been dropped or become damp is thrown away? Cracked or weakened discs can shatter in use.
- welding screens are placed between workers to stop flying particles and sparks?
- they keep at a safe distance when an angle grinder is used?
- two hands are always used to operate an angle grinder? One hand should grip the handle and ‘deadman’ switch while the other supports the weight of the tool.
- the right or left handle is used according to the user’s normal hand use.
- they never remove the guard or handles from an angle grinder?
Guards on angle grinders must be kept in place and should only be removed for maintenance and storage.
For wheel safety:
- cutting wheels or discs should not be used for grinding jobs, and grinding wheels should not be used for cutting jobs ;
- wheels designed for a particular revolution speed should not be used on machines of different speeds;
- wheels should be used only for the specific material and purpose for which they are designed, and according to the manufacturer's recommendations; and
- wheels worn small through use should be discarded and never used on smaller machines.
If subjected to pressures for which they were not designed, wheels can shatter at high speed, with the risk of serious injury to both operator and others nearby.
When replacement tools are purchased, does your workplace choose grinders which:
- are as light as practicable?
- have a left or right hand position for the handle according to suit the operator’s preference?
- have a ‘deadman’ switch that is easy to hold?
Are all angle grinders regularly checked for electrical safety to ensure:
- no breaks or damage to the machine's outer body?
- all screws tight?
- brush caps intact and firmly in position?
- sheathing of flexible cord held securely at the tool?
- no exposed wires?
- flexible cord in good condition, free from cuts or breaks?
- plugs and extension sockets free from cracks or damage?
- a safety switch or residual current device (RCD) is always used?
- all defects are repaired by a licensed electrical person?
Personal protective clothing and equipment
Is appropriate protective equipment provided and used?
- wide vision goggles, or safety glasses and a face shield;
- a hood for extra protection against particles rebounding in a confined space;
- ear muffs;
- safety boots with steel toe caps
- overalls or other close fitting clothing; and
- well fitting gloves that allow a good grip of the tool.
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