Vibration at Work: Monitoring the Exposure or Controlling the Risk?

vibration at work

Finch’s Sue Hewitt and Dr Chris Nelson take a look at vibration at work, if you need to measure employees’ exposure to vibration, and how the risks can be controlled.

When we consider occupational exposure to whole-body vibration, the main cause for concern is where an individual may be at risk of developing or aggravating a back injury. A quick look at the HSE website will reveal that, although many people are exposed to some level of whole-body vibration at work, there are relatively few occupations where the level of exposure is sufficient to create a significant risk of injury. Examples of concern include driving fast boats, off-road mobile machinery, such as in quarrying or agriculture, or driving some forklift trucks on uneven surfaces for which they are not designed; these are circumstances where there is a risk that the seated or standing operator will be exposed to damaging shocks or jolts. Where there is a significant risk, vibration exposure is often only one of several risk factors that may lead to injury. Occupations where whole-body vibration exposure is of concern (commonly off-road driving work) often involve associated activities that also carry a risk of back injury, for example, adopting awkward postures while driving or carrying out heavy lifting when loading or unloading.  If the employer assumes that the risk is related purely to the level of vibration exposure, then opportunities for effective control of the risk, for example through ergonomic intervention, are likely to be missed.

The Control of Vibration at Work Regulations 2005 apply to both hand-arm vibration and whole-body vibration.  In both cases, while it is important to identify circumstances in which vibration poses a risk of injury or disease, the priority should not be to measure or monitor the level of exposure, but to recognise where there is a problem, assess the risk and take action to control it by implementing suitable control measures. HSE guidance on whole-body vibration encourages employers to make a risk assessment without the need to measure the vibration exposure. For example, HSE leaflet INDG242 contains the following:

Do I need to measure my employees’ exposure to vibration?

No, you don’t have to do this as long as you have done the broad risk assessment and take all the appropriate and reasonable control actions described in this leaflet.”

There are many ways in which risks from whole-body vibration can be controlled, often without any need for quantification of the exposure. Examples include:

  • minimising the need for transportation of goods and materials by good organisation of the workplace;
  • maintaining vehicles in a good state of repair;
  • making any surfaces driven over as smooth as possible, for example by filling in cracks and potholes and removing rubble;
  • improving the ergonomics of the task to avoid twisting, bending and lifting and allowing for regular breaks; and
  • training drivers in the risks of whole-body vibration, correct adjustment of suspension seats and the benefits of reducing driving speeds.

A simple approach to reducing the likelihood of employees experiencing severe shocks or jolts to the spine will be a positive step to reducing the risk.  However, the daily vibration exposure (A(8) value) is little affected by the presence of potentially injurious shocks and jolts, and is, therefore, a relatively poor indicator of risk from whole-body vibration and shock.  In our opinion, although the Exposure Action and Limit Values for whole-body vibration are expressed as A(8) values, they are less helpful in assessing risk to health than those for hand-arm vibration, so the benefit from quantifying daily exposure to whole-body vibration, and in particular monitoring it on a continuing basis, should be questioned.

With advances in technology making measurement devices and data collection easier and cheaper than ever, there is an increasing temptation to adopt the approach of equipping vibration-exposed employees with some sort of monitoring device and then to rely on the performance of the device and the will of the individual to manage their own exposures. It is a common misconception that monitoring of vibration exposure (hand-arm or whole-body) is required by the Control of Vibration at Work Regulations 2005. It is not. HSE has published advice to the contrary for hand-arm vibration. Monitoring either hand-arm or whole-body vibration exposure is not a substitute for reducing the risk to as low as reasonably practicable and does not, on its own, result in compliance with the Vibration Regulations.

If employees have significant vibration exposures, then any system of setting a limit, combined with retrospective recording of exposures is likely to result, on at least some occasions, in them exceeding the set limit before they have worked out that they have done so.

Conversely, some employees will be users of vibrating equipment but will not have significant exposures and the risk will be low or unforeseeable.  Once this has been demonstrated by a risk assessment there is no value in continuously monitoring or recording exposures thereafter.

It is probably unrealistic and unreasonable to expect an employee who has been given a job to do to stop work because their vibration exposure has reached a specified daily limit.  It is likely that the need to meet deadlines or complete tasks will prevent this. We have heard of circumstances where an employer made it a disciplinary offence to exceed the Exposure Action Value. However, the employer had not put in place any provision for the job to be completed by other means, leaving employees in an impossible position. A similar situation can arise when an employee has been diagnosed with hand-arm vibration syndrome (HAVS) at an early stage and the medical advice is that they can continue working, but with reduced exposure. Some employers respond by simply instructing the individual to work to a reduced personal exposure limit, but without taking positive action to manage their need to use vibrating tools. This is unlikely to result in the reduction in the individual’s vibration exposure necessary to prevent their HAVS from progressing to a more severe stage.

The Vibration Regulations do not require monitoring of exposure, but they do require that the risk from vibration exposure is assessed and, where found to be significant, adequately controlled. The employer needs to be able to demonstrate that this has been done, and exposure data alone is not sufficient for this purpose. Compliance with the Regulations, and control of the risk, can only be achieved by understanding and planning the work allocation to make sure that vibration risk is eliminated or reduced to as low as is reasonably practicable.

Various electronic devices for monitoring and/or recording daily exposures to hand-arm vibration have been available for some years.  They can be useful, particularly during the risk assessment process when a period of sampling can provide useful information on the ‘trigger time’ involved in various work processes involving vibrating tools and equipment.  However, there is no requirement in the Vibration Regulations for continuing daily vibration exposure monitoring and recording, and the HSE does not encourage it.  In our experience, some employers rely heavily on either paper or electronic systems for recording exposure but fail to demonstrate compliance with the Regulations by showing that they have reduced the risk (and where necessary the daily vibration exposure) to as low a level as reasonably practicable by managing the work done with vibrating equipment.

In our experience, when considering the evidence produced by a defendant in a personal injury claim for HAVS, it is increasingly common to receive a pile of daily vibration exposure timesheets completed either by or on behalf of, the claimant. Alternatively, the evidence may contain data generated by a personal vibration exposure monitoring system. Both can represent a wasted resource, in terms of both time and money, that could have been put to better use, for example by changing the process to avoid vibration exposure altogether, purchasing lower vibration tools and machines, training employees in the best use of the equipment to keep vibration transmission to a minimum and documenting what has been done. This can provide evidence to demonstrate compliance, the value of which will become clear in the event of having to defend a personal injury claim for HAVS, or if an HSE inspector raises concerns about vibration.

Please contact [email protected] or [email protected] for any further information on vibration exposure and risk. Finch has a talented range of experts in the field of noise and vibration who can be viewed by clicking here.

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