The individual A(8) exposure may not exceed a value called the limit value. There is also a lower limit, which is called the action value. The EU directive stipulates the following levels of the action value and the limit value:
Hand-arm vibration; action value = 2.5 m/s2, limit value = 5 m/s2
Whole-body vibration; action value = 0.5 m/s2, limit value = 1.3 m/s2
If the A(8) exposure is higher than the action value, the employer must offer medical health surveillance and implement a programme of preventive measures to reduce the daily exposure levels so that they do not exceed these cut-offs.
An employer cannot seek a waiver from medical health surveillance (or preventive measures) if the daily A(8) exposure is below the action value. This is clearly stated in the EU directive. It also says that an exposure below the action value does not guarantee that it is safe. It even makes mention of the fact that injuries can occur even though the exposure does not exceed the action value..
The A(8) exposure dose is calculated based on the tool vibration data (emission levels) and the duration, that is, for how long the tool is used during the day.
To find out how much a tool vibrates (the emission level), you can either consult the manufacturer's data sheet or search in different databases. Umeå University maintains a Swedish database.