Controlling hand-arm vibration in the workplace

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 hand-arm vibration syndrome (HAVS) through their work activities.

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.

What is 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.

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. Nevertheless, 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 and place a clear duty on employers to ensure their staff are not exposed to excess vibration.

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.

Minimising 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

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

Simple measures to reduce hand-arm vibration

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. 

Theo Simon is an application engineer specialist in abrasives at 3M

For more information: 

www.bsif.co.uk

Tel: 01442 248744