UVP USER VIBRATION PROTECTION

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Tri-axial Vibration Values
Vibration Level for Outdoor Power Equipment
Sound Pressure Level for Outdoor Power Equipment

Converting Vibration Measurements to Trigger Time

To convert tri-axial vibrating measurements to trigger time, Power Tools recommends using the following methods: Use of a ready reckoner or use of the LowVibration.com online calculator. To use the calculator click here, to use the ready reckoner see below.

The HSE Ready Reckoner

The table below is a ready reckoner for calculating daily vibration exposures. All you need is the vibration magnitude (level) and exposure time. The ready-reckoner covers a range of vibration magnitudes up to 40 m/s2 and a range of exposure times up to 10 hours.

The exposures for different combinations of vibration magnitude and exposure time are given in exposure points instead of values in m/s2 A(8). You may find the exposure points easier to work with than the A(8) values:

  • exposure points change simply with time: twice the exposure time, twice the number of points;
  • exposure points can be added together, for example where a worker is exposed to two or more different sources of vibration in a day;
  • the exposure action value (2.5 m/s2 A(8)) is equal to 100 points;
  • the exposure limit value (5 m/s2 A(8)) is equal to 400 points;

The HSE Ready Reckoner

©HSE, This material has been reproduced under the terms of the Click-Use Licence

Using the ready reckoner

  • Find the vibration magnitude (level) for the tool or process (or the nearest value) on the grey scale on the left of the table.
  • Find the exposure time (or the nearest value) on the grey scale across the bottom of the table.
  • Find the value in the table that lines up with the magnitude and time. The illustration shows how it works for a magnitude of 5 m/s2 and an exposure time of 3 hours: in this case the exposure corresponds to 150 points.
  • Compare the points value with the exposure action and limit values (100 and 400 points respectively). In this example the score of 150 points lies above the exposure action value.
  • The colour of the square containing the exposure points value tells you whether the exposure exceeds, or is likely to exceed, the exposure action or limit value:
    Action or Limit Value
  • If a worker is exposed to more than one tool or process during the day, repeat steps 1 - 3 for each one, add the points, and compare the total with the exposure action value (100) and the exposure limit value (400).

©HSE, This material has been reproduced under the terms of the Click-Use Licence