Hand-arm vibration: to measure, or not to measure?

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The first point to consider if you are contemplating carrying out vibration measurements or going to the expense of getting someone else to carry them out for you is: Is it really necessary? In this article Sue Hewitt investigates if vibration measurements really are needed, or if the control of vibration is most important.

Hand-arm vibration: to measure, or not to measure?

If you are doing a vibration exposure assessment as part of your vibration risk assessment, then in the first instance you should look for vibration data from alternative sources. A precise assessment of daily vibration exposure is probably not necessary. It generally needs only to be good enough to determine the likelihood of the Exposure Action Value or Exposure Limit Value being reached or exceeded, so that you can identify what actions are necessary. These days there are many sources of hand-arm vibration data accessible on the internet. Some may not be reliable, but if you can find similar vibration values for the tools or processes you are assessing from two or more sources, this may be enough to get you started without having to make any vibration measurements.

Alternatively, you should be able to get information from a tool supplier or manufacturer. They should have data that represent the vibration magnitude from the typical use of the tool (which may be different from the declared vibration emission), so ask them. Tool hire companies often label their tools with vibration magnitude information. In many cases, you should be able to find sufficient vibration data to do an initial risk assessment without measurements being necessary.

Here are some websites that have vibration data:

https://www.karla-info.de/en/hand-arm-vibration/measured-hav-immission-values/

Hand-Arm Vibration Database (portaleagentifisici.it)

https://www.thetooladvisor.com/

https://op.europa.eu/en/publication-detail/-/publication/3f9392ff-8975-4139-9ea2-5b168a334664/language-en

And there is always the HSE website data:

https://www.hse.gov.uk/vibration/hav/source-vibration-magnitude-app3.pdf

If you can do a vibration exposure assessment and decide on a control action plan without measuring, you will have more resources available for any necessary controls.

However, if you are considering using manufacturers’ declared vibration information for your vibration exposure assessment (presented in terms of a and K) then you should read this excellent article first:

https://www.finch-consulting.com/can-manufacturers-declared-vibration-emission-values-be-used-for-vibration-exposure-assessment/

Of course, there are some circumstances where you might decide that measurements are necessary, for your vibration exposure assessment, for example:

  • If it is not otherwise possible to adequately assess the exposure and establish whether the EAV is likely to be reached or exceeded or the ELV is likely to be exceeded.
  • If you have taken, or are contemplating taking, some engineering control action, and you need to be able to demonstrate a reduction in vibration exposure.
  • If you are trying to select a low-vibration tool from a range of possible options. Manufacturers’ data may all suggest similar vibration magnitudes and therefore not be particularly helpful. (Although this could also mean there is very little difference between the tools, that they represent state-of-the-art in terms of reduced vibration, in which case looking for differences might be unproductive). The data may however be from standardised tests, which may not necessarily reflect the vibration when the tool is used for typical work.
  • If you have a bespoke machine for which there is little or no existing information, or if a tool/machine is being used in a novel or unconventional way (assuming it is otherwise safe to do so) or if you believe that the vibration from the machine you are using is lower than the range suggested by other credible sources of information.
  • If you are making or defending a civil claim. In civil cases, assessments may be made on generic data if no other representative data is available. This is often sufficient, however, if the actual vibration is believed to be unusually high or unusually low, it may be advantageous to have measurements.
  • If HSE is investigating or threatening enforcement action.

An important fact to remember is that measuring and monitoring of exposures does not in itself represent controlling of exposures and it is the control that is paramount. If you are still unsure and would like any help or advice regarding whether or not you need to measure vibration, or if you require help to measure having already concluded that it is necessary, please do get in touch with [email protected].

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