Vibration from hand-held power tools can cause permanent damage to the hands, wrists and arms that makes it difficult to even tie the buttons of a shirt.
As a result, employers have a legal to duty to eliminate or reduce the risks to workers’ health.
Hand-arm vibration syndrome (HAVS) is a well-known ill health effect of hand-transmitted vibration from powered hand 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 they are able to identify and report any early indications of vibration-related ill health. Key symptoms are tingling, pain, numbness, weakness and the fingers becoming white (blanching) and then red and painful on recovery.
The symptoms of HAVS are usually progressive as exposure continues, so, if exposure is stopped early enough, employees with early stages of HAVS are more likely to recover.
It is important to understand that the Control of Vibration at Work Regulations 2005 require employers to assess the daily exposure to vibration, but this does not simply mean that assessment of exposure is to be undertaken on a daily basis.
With this in mind, it is often not necessary or advisable to implement a continual monitoring programme on your site, such as continuously using ‘tool timers’ or ‘wrist-worn devices’.
When determining exposure to hand arm vibration (HAV) in the workplace, a suitable and sufficient risk assessment is crucial. This requires:
- 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
- Employers taking note of the duration of exposure (trigger times) and consider the effects of exposure for those employees whose health is at particular risk.
If an employee suspects that they have symptoms of HAVS, they should be instructed to report their concerns to their employer and to see their doctor. It is the employer’s responsibility to ensure that the employee’s work is safe and there is an acceptable working environment.
What do the Control of Vibration at Work Regulations require of employers?
The Control of Vibration at Work Regulations 2005 require employers to make a suitable and sufficient assessment of the risk to 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 Vibration Regulations, as well as the effectiveness of the steps taken. This should also estimate workers’ exposures to 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 at work include:
- Eliminating vibration at the source
- Reducing exposure to as low a level as is reasonably practicable (ALARP)
- 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
- 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.
What controls can an employer put in place to prevent or minimise HAV exposure?
The employer must eliminate exposure at the source by investigating other working methods or purchasing low-vibration tools. If elimination at the source is not reasonably practicable, then reducing exposure to ALARP is required via a programme of organisational or technical measures. The controls might include:
- Providing auxiliary equipment
- Implementing an appropriate maintenance programme for work equipment
- Limiting the duration of the task involving vibration exposure
- Providing rest facilities and adequate break periods
- Encouraging good blood circulation – for example, keeping warm and dry
- Encouraging workers to massage and exercise their fingers during rest breaks
- Ensuring that workers are aware of how to use equipment correctly and safely in order to minimise their exposure to vibration – this includes avoiding gripping or forcing a tool more than necessary
- Promoting a healthy lifestyle, such as offering help to quit smoking, given that smoking reduces blood flow.
Are anti-vibration gloves effective at helping to control exposure levels?
It must be understood that injury caused by HAV exposure is dependent on the magnitude, duration and frequency of vibration. Humans respond to HAV mainly in the range of 10 Hz to 1,000 Hz, with low frequency motion being potentially more damaging than higher frequency motion. This being said, ‘anti-vibration’ gloves can typically reduce high frequency vibration but may have little effect at mid to low frequencies.
In general, gloves will help keep the employee’s hands warm in cold conditions and help maintain good circulation to the fingers, so in this sense, they may be beneficial. Should you wish to use anti-vibration gloves, it is important that the manufacturer provides test data which shows that the particular tool used in combination with that glove is effective, determining the extent of its effectiveness and which frequencies it can be used with.
When does an employer need to implement health surveillance for their workers?
The Vibration Regulations do not state that vibration exposure below the EAV is safe but infer that no further action is required when exposure is at levels below the EAV. The EAV represents a clear risk to health which requires management and is not a distinct line between safety and the onset of vibration-related ill health.
Should it be likely that workers are exposed to levels at or above the EAV – or if the risk assessment indicates that there is a health risk – health surveillance is required.
However, exposure at or below the EAV may still result in some individuals developing HAVS, or worsening the symptoms of someone with pre-existing HAVS. As the EAV is not deemed a ‘safe’ limit, this is the reasoning behind the requirement of applying ALARP in all cases of HAV exposure.
There is some evidence that indicates the risk of HAVS to be insignificant below 1 m/s2 A(8). Health surveillance is advisable at this level, as it has an important role to play in monitoring the effectiveness of exposure controls.
Nevertheless, it should be noted that health surveillance at 1 m/s2 A(8) is not a statutory requirement but is rather considered as a more precautionary approach to worker health protection.
If an employee is diagnosed with an ill health effect or correlating disease as a result of HAV exposure, the employer must inform the employee and review the risk assessment and control measures. They should also consider some alternative work duties for that employee and provide a health review for any others who had been similarly exposed.
Mary Cameron is occupational hygiene team leader at SOCOTEC UK Ltd
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