Measuring Vibration

How do you measure Hand Arm Vibration?

Measuring an individuals’ exposure to vibration has never been more important. The Control of Vibration at Work legislation came into force since 2005. However fines and reported incidences of Hand Arm Vibration or HAVS has actually increased since then.

The Regulations state that:

'To protect employees from Hand Arm Vibration Syndrome (HAVS), and to comply with the Vibration Regulations, employers need to assess the risks from vibration and plan how to control them.'

Measuring vibration

The health risks of vibration - HAVS, Vibration White Finger, Carpal Tunnel Syndrome and WBV.

The Health and Safety Executive estimate that over 2 million workers in the UK are at risk of developing health problems from Vibration. These health risks are variously described as HAVS, Vibration White Finger, Carpal Tunnel Syndrome and whole body vibration or WBV.

It is obvious that employers need to know how to measure vibration to assess the risk of HAV. Then they can work out a plan for how to control these risks. Making employees aware of the risk of Vibration should be top of the agenda and a short online course is perfect.

A Vibration risk assessment

Having made everybody aware of the risks to health from vibration a team effort can be applied to preparing a risk assessment. In any risk assessment it is necessary to measure the risk and even more so with vibration. The amount of exposure in time and magnitude determines the level of risk.

In measurement terms we need to measure or know:

  1. Vibration magnitude for the tool or machine. Ideally obtained by direct vibration testing of the tool or machine itself. Vibration magnitude is the measurement of the rapid change in direction (acceleration) of the tool or machine and is given in units of m/s2.
  2. How long an operator will be exposed to vibration in operational time and the total time in a day.

From the above two measurements the following can be calculated:

  1. The exposure limit value, or ELV, which is the amount of vibration that people can be exposed to in any one day.
  2. The exposure action value, or EAV, this is the amount of vibration where action must be taken to reduce the level of exposure.

ELV and EAV is covered in great detail in our online short course, Vibration safety training, along with ready reckoners and links to the HSE ready reckoner. This article is only concerned with how we measure vibration.

Employers are required to provide health surveillance when exposures are at or above the EAV and in other circumstances where there is risk, for example after diagnosis of HAVS and exposure continues, but below the EAV.

Ready reckoner tables can be used to estimate vibration levels. Also manufacturers MUST provide vibration levels in their handbooks and manuals for tools and machines they supply.

The HSE provide a useful online calculator for HAV available here.

Measuring Vibration

Ready reckoners and manufacturers data are all useful ways of estimating vibration but they are not true measurements. The age of a machine, how it has been maintained and how it is used can all affect vibration levels. For a really accurate measurement it is best to measure vibration of the actual tool or machine using a vibration meter.

Portable instruments that can be attached to the vibrating tool being used are often used for this purpose. They should measure the HSE Exposure Points and the time to reach the Exposure Action Value (EAV) and Exposure Limit Value (ELV) for each power tool workers may use during the day.

Pulsar instruments manufacture a small hand held device that is ideal for measuring vibration levels.

In addition they have produced a downloadable pdf detailing 5 simple steps to control hand arm vibration in the work environment.