28
Jan
Stay Safe on Site: Hand Arm Vibration
There are many health and safety issues relevant to the construction industry. Working at height, operating plant and machinery, and wearing the correct PPE are just a few, but one of the most important issues is that of hand arm vibration.
The results of Hand-Arm-Vibration Syndrome (HAVS) may not be as sudden or as devastating as an injury caused by a fall or an accident with a piece of heavy machinery, but they are just as important. The effects of over-exposure to high vibration levels can still have a serious and life-long impact. This damage is preventable, but once the damage is done it is permanent.
When using power tools or machinery regularly for long periods of time, the vibration levels begin to have an effect on your body. Your hands may begin to tingle, or you may feel pins and needles or numbness. But these short-term sensations are not the only effects. You may even feel no short-term effects at all for months or even years, but still be at risk of long-term damage.
If you are exposed to these high vibration levels for too long they begin to damage your blood vessels by narrowing them, thereby restricting the circulation to the fingers. Vibration levels can also damage your nerves, muscles, bones and joints. This can eventually lead to severe pain, loss of sensation in your extremities, fingers going white due to certain everyday triggers, reduced grip strength, fine motor control problems, and involuntary muscle spasms.
The hand of someone with VWF
These are the classic symptoms of Vibration White Finger (VWF), which is the most common form of Hand Arm Vibration Syndrome. These symptoms can come and go, but are very often permanent. VWF is a secondary form of Raynaud’s Syndrome.
It is also possible for hand-arm vibration to cause Carpal Tunnel Syndrome (CTS), due to the entrapment or compression of nerves in the wrist. Symptoms of this nerve disorder include pain, tingling, numbness and weakness in parts of the hand. CTS can also be caused by repetitive gripping and twisting motions.
The lack of strength, sensation and control in your hands and fingers due to HAVS makes it too dangerous for you to use power tools, leaving you unable to work and earn a living.
Not only that, but the damage may also stop you from performing many leisure activities like gardening. The damage may even prevent you from something as simple as watching outdoor sports, as the cold could provoke a painful attack.
It is clear to see the hand-arm vibration exposure can ruin your quality of life. It is therefore very important to make sure that you do not end up another one of its many victims.
You are at risk of developing HAVS when using power tools, or holding workpieces that are being processed by stationary machinery. This is not an exhaustive list, but these are the most common tools that put users at risk:
> Chainsaws
> Grinders (all types and sizes, e.g. angle, die, straight, etc.)
> Hand-fed equipment (e.g. pedestal linishers, grinders)
> Impact drills
> Scaling hammers, including needle scalers
> Pedestrian controlled equipment including mowers, floor saws, floor polishers
> Powered hammers for chipping, demolition, road breaking etc.
> Sanders and polishers
> Hand-held saws for concrete, metal, ground clearance etc.
And the risk of using these tools may be greater than you realise. Regular and frequent use of modern, well-designed, well-maintained hammer-action tools is likely to result in risk after just 15 minutes. This risk becomes critical after one hour of use. For non-hammer-action tools the risk begins at one hour of usage, and becomes critical at roughly four hours of use. (Source PDF).
Make sure that you always check the manufacturer’s vibration figures, so that you know exactly when you are at risk.
As more research into the causes and effects of HAVS has been done and technology has improved, many manufacturers have begun to produce products specifically designed to combat the effects and increase your safety at work.
Since 2005, Metabo’s “VibraTech” anti-vibration handle has been included as standard with all angle grinders. Thanks to the cushioning zone created by the large volume of elastomer material inside the VibraTech handle, the operator suffers up to 60% less hand-arm-vibration. This substantial and noticeable reduction in vibration levels allows you to work longer and more effectively, using less force and producing more precise results.
Makita’s “AVT” technology is another good way to reduce the risk of injury. The AVT mechanism works by transferring air around a series of chambers, which causes a counterbalance to be pushed in the opposite direction of the piston. This cancels out the vibrations that would otherwise have been caused by the piston.
Some Makita AVT tools also feature shock-absorbing handles for extra protection. As vibrations travel down the handle, it is shifted in all directions thanks to a ball joint that functions as a fulcrum. The rubber dampeners then soak up this movement, which in turn lowers the vibration levels that are transferred to the user.
Most manufacturers now provide a range of tools with varying levels of vibration protection. Though these new anti-vibration tools often cost a little more, they pay for themselves not only by allowing you to work for longer but also by preventing you from suffering the symptoms listed earlier in this article.
Even if you do purchase an anti-vibration tool, you should still take great care not to exceed the limits on hand-arm vibration.
The Health and Safety Executive has an excellent hand-arm vibration exposure calculator to help you manage your risk, as well as “Ready Reckoner” chart that is simple to use. HSE has also produced a good guide to help you find out everything you need to know about the risks of vibration at work. So make sure that you read up on the facts and learn how to recognise the warning signs!
Finally, here is some basic advice that you should follow when working with power tools to ensure your safety:
> Always use the right tool for the job, to minimise working time and vibration exposure
> Check the vibration levels of your power tools, and make sure that you know the recommended maximum usage time
> Check your tools for wear and damage that could increase their vibration levels
> Reduce the time you spend continuously operating the tool
> Encourage good circulation by keeping warm and dry, and exercising your fingers during breaks
Talk to your employer or the HSE if you have any further concerns, and make sure to spread the warning amongst your coworkers to ensure that everyone in construction remains safe and injury-free.
References:
http://www.hse.gov.uk/pubns/indg296.pdf
http://www.hse.gov.uk/pubns/indg175.pdf
http://www.raynauds.org.uk/associated-conditions/vibration-white-finger
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