Good, good vibrations
October 1st 2004

Worryingly, the Health and Safety Executive and the Medical Research Council estimate that potentially 4.9 million workers are exposed to hand arm vibration (HAVS), 1 million are exposed to vibration levels above the current HSE action limit and 300 000 workers in the UK exhibit symptoms of vibration white finger (VWF). In July 2005 a new Directive comes into force that aims to tighten control over levels of vibration to which workers are exposed and therefore reduce the potential of HAVS.

What is HAVS and where does the problem arise?

The most well-known vibration related condition, vibration white finger (VWF) is caused by damage to the blood vessels feeding the fingers. This damage can be caused when working with hand-held power tools or hand-guided machinery, or when you are holding materials that are being processed by vibrating machinery. Regular exposure to vibrating equipment can cause these damaged blood vessels to go into spasm causing a variety of symptoms, including whiteness in the fingers, pain, tingling, numbness, reduced strength and reduced ability to perform delicate handling operations.

So what causes the problem?

Many commonly used tools and processes produce high levels of vibration. The risk depends on a number of things: the amount of vibration is important, along with how long you use the tools, the way you use them and the working conditions such as how cold it is. Individual susceptibility is also important.

The symptoms of VWF can be aggravated by the cold and by smoking. The first sign of VWF is often an occasional attack when your fingertips become white. If you continue to work with vibrating equipment the affected area can increase. Ultimately these symptoms could limit the work you can do. For example, you may not be able to continue working with vibrating equipment, work in cold or wet conditions, do work requiring finger manipulation and the syndrome may also affect your family and leisure activities.

New Rules

In order to control vibration levels workers are exposed to and therefore reduce the possibility of HAVS, revised legislation from the Health and Safety Executive is to be introduced on the 6th July 2005 that will reduce the action level requiring corrective action to an 8 hour daily exposure of 2.5m/s2. This reduction will impact industry by reducing the allowable safe working times of handheld power tools by up to 37%.

3M has developed a flat grinding disc that can offer reductions in both vibration and noise levels compared to conventional depressed centre discs. Recent independent vibration test results showed that the vibration level caused by grinding with conventional discs was reduced from 11.4m/s2 to 2.8m/s2 when the Green Corps Flexible Grinding Disc was used a 75% reduction that increased the permitted safe exposure time to 7 and a half hours per 8 hours of daily exposure (see tables 1 & 2 below).

One of 3M’s customers, Extec employs 200 workers and 20% of them use grinding tools in their daily work. We carried out risk assessments followed by a programme of health surveillance and while we were already complying with current legislation, we are continually seeking improvements explained Eddie McCreadie, health and safety manager for Extec.

We are legally obliged to assess the vibration levels that our workers may be exposed to and because of the pending changes to legislation we decided to trial the Green Corps Flexible Grinding Disc after consultation with 3M. Our workers received training from their engineers because the application of the disc is slightly different from conventional grinding discs to achieve the correct grinding technique. We discovered, very quickly, that vibration levels were reduced considerably and as a result of these trials we have now introduced the Green Corps Flexible Grinding Disc to all our workers.

Subsequent assessment has shown that the introduction of these discs in-conjunction with new low vibratory tools has meant we are not only complying with the current and pending legislation but in many cases the levels are even less than the recommendations.

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