Category Archives: Safety

Why have abrasive wheel and disc safety training?

Why have abrasive wheel and disc safety training?

I think this is a reasonable question that may be asked by an operator, supervisor, safety officer or manager. Why should an operator of equipment that uses abrasive products, having never had an injury, have training? For a supervisor or manager the time taken to have training is an expense in lost production. I as a trainer would freely admit that the majority of delegates know how to use the machine that they use for cutting, grinding, sanding or polishing. The safety officer will often put safety procedures in place in the form of risk assessments that if followed should prevent the risk of injury, serious or otherwise.

Each year thousands of people attend accident and emergency hospital wards with injuries that have been sustained when using equipment that uses abrasive products. When we run training courses we often find that at least one or two of the delegates have been injured sometime in the past when using abrasive products. Some delegates can tell of friends and collegues who in the past have been seriously injured. Then their are those that will tell us of a near miss that could have ended in tradegy.

Typical injuries include:

  • Small particles of abrasive or work material that hit the eye.
  • Flying debris that causes facial damage.
  • Wounds to the head, hand and arms and the upper part of the leg from contact with a wheel or disc.
  • Burns from sparks setting fire to clothing.
  • Hearing loss due to excessive noise.
  • Damage to fingers and hands through excessive vibration.
  • Lung problems caused by dust contamination.

In every case, without exception, the injury was totally avoidable. In some cases it was the use of poorly designed, low standard or totally inappropriate personal protective equipment (PPE). In some cases a severe lack of proper preparation and risk assessment. For some it may be using poorly maintained machinery or abrasive products totally unsuitable for the job in hand.

Training should be about how to avoid the injuries described. Each injury is costly to the employer in lost production and can be devastating for the individual concerned. As a trainer I have never come across someone who has been injured when using the right PPE. Training should be about:

  • Preparation and risk assessment.
  • Undertstanding the hazards involved.
  • The right PPE.
  • How to avoid the dangers.

This blog contains the thoughts of Mike, one of our trainers.

Personal Protective Equipment (PPE) check list for users of portable cutting equipment

• Prior to starting work. A thorough risk assessment should be employed. By assessing risk to the operator and those in the immediate vicinity suitable PPE can be determined.

Helmets and bump caps. Check date of manufacture and CE mark of helmet (EN 397:2012) or bump cap (EN812:2012). Hard hats should not be used after 3 years from date of manufacture. Check suitability of helmet or bump cap in respect of size and use in temperatures of extreme heat or cold.

Eye and face protection. Always use full face visor to EN 166:2001 (B) that has a mechanical strength to protect from objects with a speed of up to 120 M/S. Welders masks should conform to EN 175:1997 (B). Check suitability of visor to extremes of temperature and ability to protect operator from molten metals. Persons working in the area of an operator may wish to consider the use of full face visor and those that may be visitors or working within 10 to 30 metres of the working area safety glasses to EN 166:2001 (F).

Hearing protection. The safe working limit is 80 decibel with the requirement for hearing protection to be worn when the daily exposure exceeds 87 decibel. Consideration should be given to the type of hearing protection as these machines, when used, often exceed 87 decibel.

Respiratory protection. Careful consideration should be given to the type of filter protection required as the cutting or grinding process may produce fine dust particles, liquid particles, vapour or gas. The protection should be fit tested to avoid contamination and have a CE marking.

Hand and arm protection. When using these machines the risks from vibration and sparks causing injury can be alleviated by using gloves or leather gauntlets. Great care should be taken to ensure the protection does not inhibit safe control of the machine.

Suitable clothing should be worn at all times. For long periods of cutting or grinding leather overalls and hood may be used to give protection to the head, neck, shoulders and torso. However regardless of the design all clothing should be fire retardant.

Foot protection. Especially when cutting, the workpiece may move and fall from its safe position and could cause injury. It is vital that foot protection is used to give protection from falling or moving objects. Various designs are available but should conform to EN ISO 20347:2004 and a 200J toe cap.

The above offers only limited guidance to the checks required to determine the type of PPE to be used. More detailed guidance is available from the Health and Safety Executive website
www.hse.gov.uk.

Safety hazards involved with using portable cutting and grinding equipment

As with any power tool personal protective equipment is vital when using angle grinders. Typical hazards when using angle grinders can be summarised as follows:

  • Flying particles. When used correctly particles of the work material as well as that of disc will leave the working area. These particles may leave the working area at speeds of up to 80 Metres per second (M/S), approximately 180 miles per hour. Although the guard should be positioned in a manner that protects the operator, some of the particles may impact on the body. It is vital that operators wear protection suitable for impact resistance that covers the eyes but also the face as particle impact can cause serious scarring to the skin. Attention should be paid to others nearby who may require the same protective equipment or at least protective spectacles or goggles. As well as protection to the face many of the particles coming from the working area will be in the form of sparks. These sparks can easily set light to clothing. Where possible the use of leather overalls and gauntlets should be considered as well as flame retardant clothing.
  • Noise. Noise from the machine during use can damage hearing. Care should be taken in choosing the right type of hearing protection to prevent loss of hearing or damage that may result in industrial diseases such as tinnitus. Advice on many aspects of hearing are available to read and download on the Health and Safety Executive (HSE) web site.
  • Vibration. The effects of excessive vibration to an operator’s health can be devastating and as with noise can worsen with use. Hand arm vibration syndrome (HAVS) can leave the operator with pain and restrictive use of fingers, hands and arms. The HSE have extensive information available to read and download including methods to monitor vibration and the effect it can have on the health of an operator. Improvements have been made to angle grinders to reduce vibration and their are many type of gloves available that can reduce the effects of vibration. More on HAVS.
  • Dust and vapours. This may stay air born for a considerable time especially when angle grinders are used in confined spaces. Under all circumstances the operator should wear appropriate respiratory protection. Consideration should be given to the type and nature of the dust and vapours in determining the level of respiratory protection required as well as the protection required by others in or near the working area. Correct fitting of the mask is important to avoid the problem of dust entering the respiratory area. As with noise and vibration useful information is available on the HSE website.
  • Insecure work-piece. Because of the surface roughness of the work-piece care should be given as to the type of gloves required in its handling. When working with an angle grinder the work-piece needs to be fully secure, to prevent possible kick-back, allowing the operator to use the angle grinder two handed with one on the handle and the other hand on the body of the machine. Because of this, and especially with regard to cutting components, it may be expected that part of the work-piece may move from the working area. Therefore it is vital that the operator wears shoes or boots that give adequate protection from any possible contact.

For many operators the above mentioned hazards are typical of their working environment. Other types of PPE may be required to work safely and can include high visibility clothing, hard hat and more.

At Abtec we recognise that PPE is a vital part of keeping the operator of the angle grinder safe from injury. We strongly recommend before using an angle grinder the operator has suitable training in the use of angle grinders and in the use of the correct type of PPE.

More on training

Safety advice when using angle grinders

Used correctly, assessing potential risks and hazards, and with appropriate PPE, discs used on angle grinders can be highly efficient and safe for the purpose for which they were designed.

Operators of angle grinders should always check the following:

  • When changing a disc on an angle grinder the angle grinder has been isolated from its power source.
  • Suitable personal protective equipment (PPE) is worn during use.
  • The spindle speed of the angle grinder does not exceed the maximum operating speed of the disc in revolutions per minute. (RPM).
  • The angle grinder should be checked for safety. Including guard, retaining nuts ,switch, electric cable, plug, spindles and handle and if pneumatic, couplings and hose. Any damage parts should be replaced prior to use. Excessive vibration may indicate worn bearings that may create instability in the disc. Remove grinding debris that may have settled on the guard as this may come loose during use.
  • Check for any damage to the disc such as chips, cracks, warping or contamination. Destroy damaged discs.
  • Only use discs that are designed for the purpose indicated on the disc. If in doubt seek advice.
  • When using type 41 (Flat cutting discs), type 42 (depressed centre cutting disc) or type 27 depressed centre grinding disc) check the use by date has not been exceeded. This is usually found on the metal reinforcement around the bore of the disc.
  • The disc should sit on the base flange of the angle grinder securely. Depressed centre discs are designed so that the disc is raised above the base of the guard.
  • Diamond cutting blades have a rotational direction that must be aligned with the direction marked on the angle grinder.
  • When replacing the retaining nut do not over-tighten as the disc will tighten to the spindle on start up. Over-tightening may crack the disc. Special care should be taken when securing the retaining nut, with the use of a pin spanner, to thin cutting discs.
  • Rotate the disc by hand to make sure it does not come into contact with the guard.
  • Adjust the guard to be between the operator and the disc. This is important as the guard will have to be adjusted to a position suitable for either cutting or grinding.
  • Allow newly mounted discs to run at operating speed, with the guard in place, for a reasonable time before commencing cutting or grinding. During this test no person should be in line with the opening of the guard.
  • The operator should consider the proposed working area and carry out a thorough risk assessment prior to starting the angle grinder.

More safety advice

  • Always handle and store discs and wheels carefully. Cutting discs should be stacked horizontally or flat. Depressed centre discs should be placed on top each other or stored in the original packaging. Store discs away from damp atmosphere and extreme temperatures.
  • Check conformity to the respective standard of the product used. EN12413 for bonded abrasive (type 27,41 and 42 discs). EN13236 for superabrasives (diamond blades). EN13743 coated abrasives (flap and fibre discs).
  • Consider using discs marked with OSA logo. The Organisation for the Safety of Abrasives.
  • Always secure the work-piece firmly while it is being cut or ground.
  • Always use the angle grinder in a comfortable position, where the work-piece is well balanced and the angle grinder is well supported.
  • Grind at an angle above 30 degrees to the work-piece with a depressed centre grinding disc.
  • Keep the working area clear to avoid operator trips or falls. Special care should be taken with electric leads and air hose.
  • Never use a damaged discs. Destroy damaged discs.
  • Never force a disc on to a machine spindle.
  • Never use an angle grinder in poor condition.
  • Never use an angle grinder without its guard.
  • Avoid applying side pressure to a cutting disc.
  • Never try to stop a disc by applying pressure to the periphery of the disc. Always switch the machine off and allow the wheel to stop revolving.
  • Do not allow the disc to be trapped or pinched in the cut.
  • Do not apply excessive pressure onto the disc so that the driving motor slows down.
  • Never grind on the side of a cutting disc.
  • Never attach more than one disc to machine.
  • Do not drop or lower an angle grinder by the cable or airline onto the floor. A disc can be easily cracked, if it is put down hard, by the weight of the machine. This is a common cause of disc breakage.
  • Always use an angle grinder with both hands with the handle in place.

More on training in the safe use of abrasive wheels and discs.

More on OSA