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ASA rule wrist mounted HAV monitors unsuitable for regulatory risk assessment

HAVS vibration measurement

Posted on: April 10, 2019

Why did the Advertising Standards Authority have to rule on what should be common knowledge? What is HAVS monitoring best practice, what do insurers say and could zero monitoring be the best option?

You would have thought that the issues surrounding wrist-mounted vibration monitors had already been thoroughly settled. Apparently not so in the minds of some. The following is an outline of some of the very costly myths associated with HAVS vibration monitoring and a guide to the best practice options. A summary of the ASA ruling is also included.

Getting risk assessment and management right is not just an academic exercise. If companies unwittingly spend too much (or even any) of their budget on monitoring that is not necessary or compliant with the regulatory guidance, they have less to spend on risk reduction. Consequently, tool users may be at higher risk of developing vibration white finger or HAVS. Knowing of someone with such severe symptoms they are unable to use toilet paper is a salutary experience, particularly when you know that the damage could have been avoided through better risk management…

ASA ruling on HAVS measurement


We published a post to support and disseminate the information in an advance copy of the new 2017 HSE guidance, stating that wrist or glove mounted vibration monitors cannot be used to acquire operator vibration exposure data to the ISO 5349 standard. Subsequently, the manufacturer complained to the ASA as they disagreed with the contents.

Following a review of the technical submissions, the ASA has ruled (read the full ruling here) that the information in the post was both correct and accurate.

ASA rules against manufacturers’ claims, stating “We considered that because we had seen evidence that wrist-mounted transducers did not measure hand-arm vibration in accordance with the Standard, did not provide ELV or EAV data that was required by the Regulations and were not, therefore, suitable for risk assessments of hand-arm vibration as set out by the Regulations…
We considered that because INVC had shown that wrist mounted devices did not measure hand–arm vibration in accordance with the Standard, or produce the data required by the Regulations, essentially because they did not measure vibration where the surface of the tool made contact with the hand, the data captured by a wrist mounted device was likely to be problematic when defending a claim for exposure to hand–arm vibration and therefore a decision to use such devices may put employers at risk of financial loss… The claims (against INVC) were not upheld.”

The HSE response to the ASA ruling

The ASA requested HSE comments before publishing the ruling. The HSE reiterated -

The Control of Vibration at Work Regulations, which set the action and limit exposure values for vibration and which refer to international and the British Standard BS EN ISO 5349, stipulate that measurements are to be taken on the surface of the equipment in contact with the hand. The requirement is also reflected in its guidance, which notes that, although measurement may sometimes be required, it may not be necessary if suitable vibration data is available... measurements taken elsewhere, including the wrist, would not provide the data required by the standard or the regulations.
There is no legal requirement for the continual monitoring or recording of exposure to vibration unless there are specific circumstances. What employers must do is decide what workers' exposure is likely to be, as part of a vibration risk assessment.
If the risk assessment indicates the need for monitoring, then a timing system/device could be used in combination of representative vibration magnitude data. Measurement of vibration magnitude will not usually be required but may be necessary if representative vibration data are not readily available. The measuring system used should measure according to the requirements of BS EN ISO 5349-1: 2001. This standard specifies that vibration measurements shall be made on the vibrating surface at the point where the vibration enters the hand (or hands).

A very clear endorsement of the INVC statements in support of the HSE guidance.

HSE guidance – HAVS monitoring best practice – Insurers

There are 3 key elements covered in the latest HSE HAVS guidance.

  • The first states that there is no requirement to continually monitor workers’ exposure to vibration and that it is “probably not good use of your or your employees’ time except for very specific circumstances”.
  • The second is concerned with measurement technique. This specifically states that “Hand-arm vibration measurements should be made with the transducer firmly attached to the vibrating surface” (as per BS EN ISO 5349-1 2001) and “There is currently no wrist or glove mounted device which measures vibration suitable for use in a vibration risk assessment.” This is completely unambiguous and, you might (perhaps naively) think, not open to much interpretation…
  • The third is that you should focus on taking practical action to control and reduce exposure and risks. We advise that you should almost always spend your resources on risk reduction actions rather than on costly placebo monitoring that tells you what you already know – that there is a risk. It comes down to a cost/benefit analysis: would the money and resources spent on monitoring (which is not required by the HSE) be better spent on improving processes and equipment? Moreover, where cases do go to court, the concern is almost always over the actions, or lack of actions, to manage risk, not over the measurements themselves.

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Parts of the literature associated with some of the monitoring systems, however, either completely ignore the regulatory guidance or “reinterpret” it to suit. It has also been suggested that while there is no legal requirement to continually monitor workers’ exposure to vibration, insurance companies recommend it. The major insurer, QBE, begs to differ. In the QBE HAVS guidance they state “…there is no requirement in the Control of Vibration at Work Regulations 2005 for continual monitoring of exposures and QBE does not expect this as a condition of insurance.”

Placebo vibration measurement instead of action

There is an increasingly sophisticated hand-arm vibration monitoring industry that encourages a “risk measurement” culture where assessment is an end in itself rather than just a precursor to the greater challenge of using the information to guide actions to reduce risk. As illustrated above, whilst much of this industry is honest about the capabilities and uses of their monitors, some suppliers seem determined to muddy the waters surrounding HAVS exposure measurement. The key question to ask before implementing a measurement or monitoring strategy is “Will additional measurements affect my risk reduction actions?”

HAVBase HAV vibration database.png

If the answer is “no”, then don’t do it. If the answer is “yes”, then the choice comes down to the results of a cost/benefit analysis. Would the cost of the additional measurements or monitoring provide sufficient benefits to be worthwhile compared with alternatives such as rapid virtual assessments from field vibration databases at a tiny fraction of the cost and hassle? Would it be better to spend the resources saved on risk reduction strategies instead?

We have and do recommend the use of various forms of continuous monitoring systems for certain (usually high risk) activities as an aid to gathering data (finger-on-trigger times in particular). Once the initial data is in, however, there is usually no need to continue monitoring unless it can be justified on the grounds of a cost/benefit analysis – something we generate when evaluating what would constitute best practice for an organisation.

Keep in mind the fact that both the HSE and the courts are likely to judge you on your risk reduction actions, not on the details of your measurements. They also advise that you should use reliable published field vibration data for risk assessments wherever possible and that companies should spend their time and resources reducing risk rather than on placebo assessments based on re-measuring and reassessing tools and activities for which they already have good data.

The future of HAVS risk monitoring and assessment

There is no doubt that, in principle, the way that HAVS risk is assessed could be improved. The level of vibration from a tool is just one of the risk factors. The other main workplace factors that affect risk are temperature, grip strength (ergonomics), tool productivity and individual susceptibility (e.g. blood flow into the hands). Unfortunately, the Action and Limit Values include a decimal point that lends a false air of precision to the data. 5.0m/s2 A8 actually means “this is a rough guess; it could be perhaps 3 – 4 m/s2 at low temperatures and where high grip strength is used, but possibly 6 – 7 m/s2 for very low grip strength and at high temperatures”. In other words, variables other than tool vibration and trigger time have a substantial effect on the risks to individual operators for a given vibration exposure.

However, as a very experienced engineer in the field of vibration measurement (when I started, you had to put together your own vibration monitoring kit from discrete components and manually apply the HAV filter!), I can tell you that developing an improved version of ISO 5349 that could take some of these risk factors into account would be a very, very long-winded nightmare of a technical challenge. You can’t just rock-up and claim that your latest wrist or glove mounted monitor design is the one true vibration dosimeter that evaluates operator risk, despite the fact that it doesn’t measure to the standard and therefore the data cannot be compared with the ELV or EAV values in the regulations.

What do you think about HAV measurement?

I’d be very interested in any feedback or experiences that you may have on the subject of vibration monitoring or any of the other issues raised in this post. Email any comments using our contact form here>.

Peter Wilson, Technical Director

Contact us if you’d like our independent take on HAVS monitoring and risk management. In addition to our other services and IOSH HAV competency courses, we also run a HAV Master Class as both a public and an in-house workshop or management briefing (0.5 – 1 day). It not only provides a review of the practical implications of the HSE guidance and the limitations of the various vibration measurement and monitoring systems, but it also provides a forum in which to discuss existing risk management procedures and the ways to improve them using current best practice. Effective vibration risk management is often far simpler and very much less costly than you might think.