Take control

NEARLY TWO million people are at risk of hand-arm vibration in the UK.¹ Although it’s a very preventable condition, there were still 205 new cases of hand-arm vibration syndrome (HAVS) reported to the Health and Safety Executive in 2019 and 135 cases of carpal tunnel syndrome (CTS).²

Using hand-held, hand-fed or hand-guided tools or machines can cause hand-arm vibration syndrome, carpal tunnel syndrome and dupuytren’s contracture. All of these conditions are preventable but once the damage is done, it is irreversible and it is painful and disabling. An estimated five million people in Britain are regularly exposed to HAVS through their work activities.³ Not surprisingly, the greatest focus of risk is found in industries where there is repeated and frequent use of hand-held vibrating tools - for example, power drills, orbital sanders and angle grinders, found in sectors such as foundries, heavy steel fabrication and construction. 

Health and safety is integral to everyday operations in every industry and no more so when it comes to abrasive applications, for example in industries such as metal fabrication, foundry, aerospace and rail. Ensuring processes and systems are the safest they can be will help create a safe and efficient workplace.

What is hand-arm vibration syndrome (HAVS)?

Hand-arm vibration comes from the transfer of vibration from powered tools and equipment to an operator’s hand, which can lead to tingling and numbness in the fingers. HAVS consists of three components: vascular damage to blood vessels; neurological damage to nerve endings; and musculoskeletal manipulation issues. Warning signs of HAVS include tingling, numbness and an inability to feel things with the fingers. They also include a loss of strength in the hands and ‘vibration white finger’ (VWF). This is related to poor blood circulation through damaged vessels and turns fingers white especially in cold or damp conditions. As the blood returns, the fingers go red and the sufferer feels intense pain. Continuation of high-vibration power tool use will only lead to these symptoms getting worse.

Working regularly with hand-held or hand-guided power tools for more than a few hours each day can lead to damage to nerves, blood vessels and joints of the hand, wrist and arm. Those at particular risk are workers who regularly operate hammer action tools for more than about 15 minutes per day; or some rotary and other action tools for more than about one hour per day. The types of machines most likely to cause a risk include chainsaws, cut-off saws, jigsaws, concrete breakers, hand-held and pedestal grinders, hammer drills, powered sanders, polishers and brush cutters. 

Controlling the risks from hand-arm vibration exposure

Factors affecting the level of risk from HAVS are complex and there are many which lead to a poor understanding of risk management. These include how the equipment is operated, the worker’s posture and grip, whether operators’ working conditions are cold or wet and if the operator has a history of previous injuries or use of vibrating machinery outside of work. However, the significant factors are; the vibration magnitude of the tool, how long the equipment is used for and how many vibration processes the worker is exposed to, as the impact of exposure is cumulative. 

The Control of Vibration at Work Regulations 2005 were introduced to better protect workers from vibration at work and came into force in July 2005. These regulations place a clear duty on employers to ensure their staff are not exposed to excess vibration.

Daily exposure is expressed in terms of magnitude of vibration at the user’s grip point (in m/s² and the time spent using the equipment in a shift. Some machinery can reach the Exposure Limit Value in minutes. 

	A(8) - 8 hour shift m/s2	Equivalent Points
Exposure Action Value (EAV)	2.5	100
Exposure Limit Value (ELV)	5.0	400

The Exposure Action Value of 2.5 m/s² A(8) is equal to 100 points and the Exposure Limit Value of 5 m/s² A(8) is equal to 400 points.

When the Exposure Action Value (EAV) is reached, a health surveillance programme must be implemented along with a programme of organisational and technical measures to reduce exposure to the lowest reasonably practicable levels. The Exposure Limit Value (ELV) must not be exceeded. The employer must go back to safety-first principles and carry out a risk assessment to assess and identify what is causing the issues.

The Vibration Regulations require employers to:

• carry out a full risk assessment

• make sure that risks from vibration are controlled and reduced

• provide information, instruction and training to employees on the risk and the actions being taken to control risk

• provide suitable health surveillance

Minimising exposure to vibration

The Health and Safety Executive (HSE) states: ‘The most efficient and effective way of controlling exposure to hand-arm vibration is to look for new or alternative work methods which eliminate or reduce exposure to vibration.’ 

Changing the way that an operator works, so that their time on the machine is reduced or removed altogether, is the ideal. If this is not possible, then it is recommended that workers be protected from HAVS through:

• using alternative non-vibrating methods

• mechanising or automating a task

• using jigs, clamps or rigs when possible

• alternating vibrating and non-vibrating work

• rotating vibrating work among several people

• using the best tools and abrasives available

As identified, the two key variables that can control exposure are the magnitude of vibration to which an individual is exposed and their time of exposure. Magnitude of exposure can be gauged using industry standard tri-axial transducer measuring equipment that assesses the processes vibration magnitude and tool timer equipment that shows the operator’s length of exposure - sometimes called ‘trigger time’. The exposure value can then be calculated using the HSE hand-arm vibration calculator.⁴

Simple measures to reduce hand-arm vibration

Often the simplest measure to reducing HAV is correct tool and abrasive selection. Recent innovations by the leading manufacturers in tools and abrasives are driving reductions in HAVS. For example, tools with electric or mechanical balancing systems can offer reduced magnitude compared to non-balanced tools. Selecting the right abrasive product for the application is also important. Using high performance, Engineered Abrasives with new mineral technology (like Precision-Shaped Grain) enables better rotational balance that helps reduce vibration, additionally removing material at a faster rate than conventional abrasive grains, further reducing trigger time. 

As the HSE advises, the best way of controlling exposure to hand-arm vibration is to find ways to eliminate or reduce exposure to vibration. Simple changes like selecting the best tools and products, can not only provide a significant reduction in vibration exposure, but improved productivity as well. 

References

1. ^{https://www.hse.gov.uk/vibration/hav/keymessages.htm}

2. https://www.hse.gov.uk/statistics/causdis/vibration/index.htm

3. https://www.hse.gov.uk/vibration/hav/keymessages.htm

4. https://www.hse.gov.uk/vibration/hav/vibrationcalc.htm

^{Theo Simon is an application engineer specialist in abrasives at 3M. For more information, visit www.3m.co.uk}