Hand-Arm Vibration: How should employers be protecting workers?

What do employers need to understand with regard to employee exposure to Hand-Arm Vibration?

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.

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 e.g. ‘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.
• 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 2, 3, 4 even 5 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 and by real people. It should be borne in mind that doubling the vibration levels results in 4 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)
• 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
• 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.

What controls can an employer put in place to prevent or minimise Hand-Arm Vibration 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. Controls 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 e.g. keeping warm and dry
• Encouraging workers to massage and exercise their fingers during break periods
• 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. Anti-vibration gloves have little effect at the most damaging frequencies. Some evidence suggests the use of anti-vibration gloves increases the worker’s grip and could actually increase the overall risk. Investment in good quality gloves to help keep the employee’s hands warm and dry in cold conditions and help maintain good circulation to the fingers, is likely to be more beneficial.

When does an employer need to implement health surveillance for their workers? 

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 under the CVW Regulations.

Research from a number of sources has shown that employees regularly exposed to vibration above the ELV have a 50% chance of developing HAVS, a clear risk to health. The same research has shown that workers regularly exposed to vibration between the EAV and the ELV have a 28% chance of developing HAVS, this is still a significant risk. Although the regulations infer that no further action is required when exposure is below the EAV, research has shown that there is still a 6% chance of developing HAVS. In addition, exposure at or below the EAV may result in worsening of the symptoms of someone with pre-existing HAVS.

There is some evidence that indicates the risk of HAVS to be insignificant below 1m/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 1m/s² A(8) is not a statutory requirement but is rather considered as a more precautious approach to worker health protection. 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.

If any 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 consider some alternative work duties for that employee to prevent the condition from developing further.