So far you have learnt about the main types of abrasive wheels and their uses, the main legal precautions, how to carry out a risk assessment, and the safe practices for storing, mounting, using and dressing wheels.

This final module covers the other main hazards of working with abrasive wheels, and it is useful to anyone who stores, mounts, uses or dresses them.

When using abrasive wheels it is important to keep the serious risks to health in mind, not just the risk of injury. This module covers the precautions against harmful dust from grinding and cutting, and the risks from vibration and noise, all of which cause damage that builds up slowly and is often permanent.

The module also covers eye and face injuries, fire hazards and hot work, electrical safety, hand-held grinders, training and inspection, the reporting of accidents, and first aid and emergency procedures.

This module covers the following topics:

• The main hazards, summarised
• Preventing eye and face injuries
• Harmful dust and respiratory protection
• Vibration hazards and hand-arm vibration syndrome
• Reducing and controlling noise
• Fire hazards and hot work permits
• Electrical safety
• Hand-held grinders and cutting-off tools
• Training, consultation and inspection
• Reporting accidents and dangerous occurrences to the HSA
• First aid and emergency procedures

The main safety hazards when using abrasive wheels are:

• Abrasive wheels failing because of overspeeding, being warped or damaged, being mounted incorrectly, or being used for the wrong job.
• Becoming trapped between the abrasive wheel and the work rest, or other moving parts of the machine.
• Eye and face injuries from wheel failure or from flying particles of metal and abrasive.
• Kickback from hand-held cutting-off tools when the disc jams in the cut.
• Fire from sparks landing on flammable or combustible material.
• Electric shock from damaged cables, plugs or switches.

These are the hazards that cause sudden, traumatic injury. They are controlled mainly by the practices you learnt in Module 3: correct wheels, correct mounting, guards, work rests and safe working methods.

The other hazards of using abrasive wheels are hazards to health, and they act more slowly:

• Inhaling grinding dust, which can contain metal particles, abrasive grit and, when cutting concrete or stone, respirable crystalline silica.
• Hearing damage from high noise levels over months and years.
• Hand-arm vibration syndrome (HAVS), caused by using vibrating hand-held grinders and cutting-off tools, and by holding workpieces against a grinding wheel.
• Skin conditions such as dermatitis from metalworking fluids and coolants.

These hazards rarely cause an accident that gets reported. Instead they cause permanent conditions, deafness, damaged lungs, and hands that no longer work properly, that only become obvious years later. That is why the risk assessment must cover them, and why the controls in this module matter.

Particles are thrown out during almost every grinding operation, and they travel at very high speed. Being struck in the eyes or face by particles of abrasive, metal or other material is the most common injury from abrasive wheels.

Most pedestal and bench grinding machines can be fitted with fixed transparent screens above the wheel. These are particularly useful where a machine is used by different people for short periods. Screens must be made of toughened or laminated glass, or another strong transparent material that gives a clear view, and they must be kept clean and replaced when pitted.

A screen is not a substitute for personal eye protection. For all grinding and cutting operations, eye protection is required, and for cutting-off work face protection as well. Goggles or face shields with a minimum impact rating of EN 166 Grade B (medium energy impact) are recommended; ordinary safety spectacles are not enough for grinding.

If anything gets into a person's eye, do not rub it and do not try to remove an embedded particle. Rinse with clean water or eyewash and get them to a clinic or emergency department as soon as possible so that a qualified medical professional can treat it. A lack of care can make the injury much worse.

The particles produced by abrasive wheels can cause serious health problems. Grinding dust and debris can damage the lungs and cause other harm, and cutting stone, brick or concrete releases respirable crystalline silica, which causes silicosis and lung cancer.

The first step is to minimise the dust at source by choosing the right abrasive. An unsuitable product generates large amounts of dust and debris. Employers should consult the wheel manufacturers to make sure they choose the correct wheel for a particular task.

Most portable and fixed grinding machines can be fitted with local exhaust ventilation (LEV), either a hood at the machine or a shroud and extraction hose on a portable grinder. LEV should be provided for any machine or process in regular use, and for stone and concrete cutting, water suppression should be used as well.

It is the employer's responsibility to make sure that suitable extraction is provided and fitted to grinding and cutting machines, that it is tested and maintained, and that it is actually used.

Where extraction cannot control the dust adequately, or the equipment does not have it, everyone using grinding and cutting machines must be given suitable respiratory protective equipment (RPE).

Suitable RPE includes:

• Disposable filtering face-piece masks to EN 149, class FFP2 or, for silica and fine metal dust, FFP3.
• Reusable half masks or full-face masks fitted with P2 or P3 particle filters.
• Powered air respirators for prolonged or heavy work, which are also more comfortable and do not depend on a tight face seal.

It is important to know which materials are being cut or ground, because some require a higher level of protection than others. Your risk assessment for grinding must specify the type of RPE to be used.

Employers must make sure that a face-fit test is carried out by a competent person for everyone who uses tight-fitting RPE; a mask that does not seal to the face gives almost no protection, and a beard stops it sealing at all. All RPE users must be trained in the correct use of their respirator, and for reusable respirators they must also know how to check, maintain and clean them and when to change the filters.

Grinding and cutting with hand-held machines can cause vibration injury, known as hand-arm vibration syndrome (HAVS). It damages the blood vessels, nerves, muscles and joints of the hands and arms, causing tingling, numbness, loss of grip strength and, in the classic 'vibration white finger', fingers that turn white and painful in the cold. Once established, the damage is permanent.

HAVS is a serious condition and employers have a legal duty under the Control of Vibration at Work provisions of the General Application Regulations 2007 to assess and reduce the risk. The daily exposure action value is 2.5 m/s² A(8), and the daily exposure limit value is 5 m/s² A(8), which must never be exceeded. Employers can reduce the risk by:

• Using modern, low-vibration equipment. Manufacturers are legally required to provide vibration data and information on precautions.
• Keeping all equipment in good condition. Workers should stop the machine and investigate if there is more vibration than usual.
• Using good-quality abrasives and keeping them balanced and dressed throughout their service life.
• Keeping the mounting flanges and backing pads in good condition and replacing them when worn or damaged.
• Planning the work so that vibration exposure is shared, with breaks and job rotation to limit each person's daily 'trigger time'.

Employers should give the following guidance to everyone who uses abrasive wheel equipment:

• Do not grip the machine more tightly than you need to, and do not apply excessive pressure on the abrasive. Let the tool do the work.
• Avoid using a grinding machine continuously for long periods. Manufacturers provide information on maximum continuous use times; keep a note of your trigger time.
• Use a suitable abrasive wheel for the job. An unsuitable, worn or unbalanced wheel causes excessive vibration.
• Do not ignore the physical signs of vibration damage, such as pins and needles, numbness, tingling or cold, white fingers. Report them and seek medical advice early, when the condition can still be stopped from getting worse.
• The effect of vibration is worse in the cold, so keep your hands warm and dry, wear gloves, and exercise your hands and fingers regularly during breaks.
• Do not smoke: smoking reduces blood flow to the fingers and makes vibration damage worse.

Where the risk assessment shows that exposure is above the action value, employers must also provide health surveillance so that early signs of HAVS are picked up.

Grinding equipment often produces significant noise. A pedestal grinder in use produces around 90 to 95 dB(A), and an angle grinder cutting steel can exceed 100 dB(A); both are high enough to require the employer to act.

The Control of Noise at Work provisions of the General Application Regulations 2007 set a lower exposure action value of 80 dB(A), an upper exposure action value of 85 dB(A), and an exposure limit value of 87 dB(A) for daily or weekly personal exposure, with a peak sound pressure limit of 140 dB(C). At 80 dB(A) hearing protection must be made available; at 85 dB(A) it must be worn and hearing protection zones marked; 87 dB(A), measured inside the ear protection, must never be exceeded.

Harmful noise at work, whether continuous or intermittent, causes permanent hearing damage, including deafness and tinnitus, a constant ringing in the ears. Employers have a duty to control the risk, and workers must use the controls provided.

Using grinding equipment must be included in the workplace noise assessment. If there are no other noisy processes, it can be assessed as part of the grinding risk assessment. Remember that hearing protection can create other dangers, such as not hearing an approaching forklift or a fire alarm, so take those risks into account too.

The risk assessment determines the noise level at each task and therefore where hearing protection is needed. Suitable hearing protection must be provided and used, but reducing the noise itself always comes first. Appropriate noise control measures include:

• Identifying who is at risk, including people working near the grinding area and not just the operator.
• Reducing noise at source where possible, rather than relying on hearing protection: quieter machines, sharp and well-dressed wheels, damping the workpiece, and enclosing or screening the grinding bay.
• Setting up properly marked hearing protection zones where the upper action value is reached.
• Providing the right information and training to employees on the risks and the controls.
• Providing suitable hearing protection, ear defenders or earplugs, with enough attenuation for the noise levels measured, and making sure it is worn correctly for the whole exposure.
• Making sure anyone near a noisy process, not just the operator, also has adequate hearing protection.
• Providing hearing checks (health surveillance) for workers regularly exposed above the upper action value.

Depending on the material, grinding and cutting produce showers of sparks. This kind of work is classed as hot work, because the sparks, which are tiny pieces of red-hot metal, can travel several metres and start a fire in flammable or combustible material long after the work has finished.

There have been cases where entire factories were destroyed by fires caused by grinding and cutting, particularly during maintenance and repair of the building structure, where sparks fell into roof voids, insulation or stored materials.

When planning grinding and cutting-off operations, the employer must consider:

• Are there flammable or combustible materials in the work area — solvents, fuel, gas cylinders, timber, paper, packaging, dust? Before starting, they must be removed or protected from sparks with fire blankets or screens.
• Is a hot work permit required? A permit should apply to all grinding and cutting for maintenance and repair, and anywhere outside a dedicated grinding bay.
• Has everyone doing the work been instructed on the hot work permit requirements?
• Have all precautions been taken, including a suitable fire extinguisher within reach and, where needed, a fire watch?
• Are there arrangements for a fire watch and inspection of the area for at least an hour after the hot work has finished, since smouldering material can flare up later?

Electrically powered grinders contain several components, the motor, switch, cable gland, cable, plug and socket, and every one of them must be serviced and maintained to prevent hazards. Electrical faults cause fire, electric shock and burns, and a grinder is often used in exactly the conditions that make shock most likely: damp, outdoors, with the cable dragged over sharp edges and through swarf.

Employers should consider:

• Using 110-volt tools supplied through a centre-tapped transformer, so that the maximum voltage to earth is only 55 V. This is standard on construction sites and anywhere there is a risk of cable damage or water on the floor.
• Battery-powered grinders, which remove the trailing cable and the shock risk altogether for lighter work.
• The routing of electrical cables, keeping them clear of sharp edges, hot metal, sparks, water and traffic.
• Where 230-volt grinding and cutting tools must be used, always using a residual current device (RCD) rated at 30 mA, and testing it before each use.
• Inspection and testing of all portable electrical equipment by a competent person, often called Portable Appliance Testing (PAT), together with a visual check by the user before every use: cable, plug, casing and switch.

Hand-held grinders and cutting-off tools, above all the angle grinder, are used in almost every work environment, and they account for a large share of abrasive wheel injuries. Safety considerations include:

• Arranging regular cleaning and servicing of portable grinders.
• Correctly fitting and adjusting the guard, positioned between the disc and your body. A grinder with the guard removed must not be used.
• Checking the speed marked on the machine and the backing pad, and making sure the disc's maximum speed is not lower than the machine's speed.
• Using the correct disc for the job: never use a cutting disc for grinding or a grinding disc for cutting, and never fit a disc larger than the machine is designed for.
• Clamping the workpiece so that it is held securely; never hold it in your hand or under your foot.
• Regularly checking the dead-man's switch so that the tool stops as soon as the switch is released, and never taping or wedging the switch on.
• Keeping the floor around the work area clean and clear.
• Never using a warped, chipped or out-of-date disc.
• Holding the grinder firmly with both hands, using the side handle, and standing so that a kickback will not throw the disc into your body.
• Keeping the electrical cable in a safe place, away from the disc, hot metal, sparks and sharp edges.
• Letting the disc stop completely before putting the grinder down.
• Wearing suitable PPE: eye and face protection, gloves, hearing protection and respiratory protection where needed.

Employers are legally required to make sure that their employees receive the training they need on health and safety at work, and on the safe use of any equipment provided to them. For abrasive wheels that means specific training for everyone who mounts, dresses or uses them, with refresher training at regular intervals and whenever equipment or methods change.

Employers must make sure that health and safety information is available and understood, for example through regular toolbox talks and briefings, and they must consult employees and their safety representatives on the risks and the controls.

Employers must also inspect work areas and equipment regularly. There should be a simple system that lets everyone report faults, damaged discs, missing guards or defective cables, so that they are put right quickly and the equipment is taken out of use in the meantime.

Finally, employers must make sure that serious incidents are reported to the Health and Safety Authority (HSA) as required by the Safety, Health and Welfare at Work (Reporting of Accidents and Dangerous Occurrences) Regulations 2016. Any accident that keeps a worker off work for more than three consecutive days must be reported, and so must certain dangerous occurrences even where nobody is hurt, including the bursting of a grinding wheel. Lessons learned must then be applied across all the work involved.

Your employer must have suitable arrangements for dealing with any injury or incident that could harm someone in the workplace, and everyone who works with abrasive wheels must know what they are.

Under the General Application Regulations 2007 there must be an appropriate level of first aid provision on site. As a minimum, the employer must have:

• A well-stocked first aid kit, with eyewash, that is checked and replenished regularly.
• A designated person or people responsible for first aid arrangements and for calling the emergency services.
• Information for all employees on the first aid arrangements: who the first aiders are, where the kit is, and how to raise the alarm.

In workplaces with more serious risks, which includes any workplace where abrasive wheels are used regularly, a trained occupational first aider will be needed. The workplace risk assessment helps the employer decide how many first aiders are required, taking account of shifts, remote sites and lone working.

The emergency plan must cover the risk of fire and other serious dangers. It should set out what to do in an emergency, how to stop the machines and isolate the power, the escape routes and assembly point, and name the fire marshals and other designated people.

Everyone who works with abrasive wheels should know these basic emergency actions:

• Wheel burst or machine failure: switch off and isolate the machine, keep everyone away from it, and do not restart it or remove the fragments until the incident has been recorded. It must be investigated, and a burst wheel is a reportable dangerous occurrence.
• Serious cut or bleeding: apply firm direct pressure with a clean dressing, raise the limb, keep the person still and call the first aider and emergency services. Do not remove an embedded fragment.
• Eye injury: do not rub the eye. Rinse with eyewash or clean water for at least ten minutes for dust or chemical splashes. For an embedded particle, cover the eye loosely and get the person to hospital.
• Burns from hot metal or sparks: cool with running water for at least twenty minutes and cover with a clean, non-fluffy dressing or cling film.
• Fire: raise the alarm first. Only tackle a small fire if you are trained and it is safe to do so; otherwise evacuate to the assembly point.
• Electric shock: do not touch the person until the power is off. Isolate at the switch or socket, then call for help and start first aid.

Report every incident and near miss, however minor. Near misses are free lessons: a disc that shattered without hurting anyone tells you exactly what will hurt someone next time.