HAND/ARM VIBRATION
HAV YOU GOT THEM PROTECTED?
What do employers need to understand in regard to employee exposure to hand- arm vibration? Here, David Wright, Occupational Hygiene Team Leader at SOCOTEC UK Ltd, explains the rules and regulations.
Hand-arm vibration syndrome (HAVS) is a well- known ill-health effect of hand-transmitted vibration from hand held or guided tools. Exposure to hand- transmitted vibration can cause serious ill-health effects, such as damage to the nerves, impaired blood supply or carpal tunnel syndrome.
The signs and symptoms of HAVS should be understood by both the employer and employees so that they may be able to report symptoms of tingling, pain, numbness, weakness, the fingers becoming white (blanching) and then red and painful on recovery. Early intervention can stop the symptoms progressing to serious disability.
“MANUFACTURER’S PUBLISHED VIBRATION LEVELS SHOULD BE TREATED WITH SOME CAUTION WHEN PREPARING RISK ASSESSMENTS.”
It is important to understand that the Control of Vibration at Work Regulations require employers to assess the daily exposure to vibration. It is often not necessary or advisable to implement a continual monitoring programme on your site, for example, ‘tool timers’ or ‘wrist-worn devices’, but rather the approach of a suitable and sufficient risk assessment to determine sources of vibration, determine risk and implement controls to limit risk, including: observing specific working practices; referring to relevant information on the probable vibration magnitude; if necessary, measuring the magnitude of vibration to which employees are liable to be exposed; the employer should also take note of the duration of exposure (trigger times) and consider the effects of exposure for those employees whose health is at particular risk; and, audits to check on employee exposure suing HSE exposure points system on a routing basis.
Manufacturer’s published vibration levels should be treated with some caution when preparing risk assessments. It is important to remember that the manufacturer’s figures are derived from perfect tools in ideal laboratory conditions. Real-life measurements of vibration in the field can be orders of two, three, four and five times the manufacturer’s figures. This is not because the manufacturer’s figures are necessarily wrong, but real tools have wear and tear, are often used in less than ideal conditions on different materials
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and by real people. It should be borne in mind that doubling the vibration levels results in four times the exposure due to the relationship between measured vibration and actual dose.
Real measurements do not only provide a more accurate estimate of true exposure, but can show up defects in tools such as worn bearings, twisted drive shafts etc. In addition, poor posture or grip adopted for certain tasks (which can increase vibration exposure) can also be identified. This can also eliminate potential ergonomic issues. Manufacturer’s data is good for comparing different models of tools for the lowest vibration.
WHAT DO THE CONTROL OF VIBRATION AT
WORK REGULATIONS REQUIRE OF EMPLOYERS? The Control of Vibration at Work (CVW) Regulations 2005 require employers to make a suitable and sufficient assessment of the risk for employees who carry out work that is liable to cause exposure to vibration. The risk assessment should identify the measures that need to be taken to meet the requirements of the CVW regulations, as well as the effectiveness of the steps taken. This should also estimate workers’ exposures to hand-arm vibration (HAV), comparing these against the exposure action value (EAV) of 2.5 m/s2 A(8) and the exposure limit value (ELV) of 5.0 m/s2 A(8). (A(8) refers to the ‘daily exposure to vibration’.)
Other required actions regarding the control of exposure to vibration in the workplace include eliminating vibration at the source; reducing exposure to as low a level as is reasonably practicable (ALARP) and ensuring that exposure does not exceed the ELV; taking further actions should the EAV be exceeded; undertaking health surveillance if a risk to health is indicated or exposure exceeds the EAV; and providing employees with suitable and sufficient information, instruction and training.
Once the risk assessment has been carried out, this should be reviewed regularly. If there is reason to suspect that the risk assessment is no longer valid or there has been a significant change in the work to which the assessment relates, the employer should regularly review the effectiveness of control measures, monitor tool conditions and ensure that an adequate tool maintenance regime is in place. Regular testing of vibration levels of tools is also required as part of the review as tools wear potentially increasing vibration levels.
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