Act 1974.  is the legislation in the UK that governs exposure to vibration and assists with preventing HAVS occurring. Good practice in industrial health and safety management requires that worker vibration exposure is assessed in terms of acceleration, amplitude, and duration. Using a tool that vibrates slightly for a long time can be as damaging as using a heavily vibrating tool for a short time. The duration of use of the tool is measured as trigger time, the period when the worker actually has their finger on the trigger to make the tool run, and is typically quoted in hours per day. Vibration amplitude is quoted in metres per second squared, and is measured by an accelerometer on the tool or given by the manufacturer. Amplitudes can vary significantly with tool design, condition and style of use, even for the same type of tool.In the UK, Health and Safety Executive gives the example of a hammer drill which can vary from 6 m/s² to 25 m/s². HSE publishes a list of typically observed vibration levels for various tools, and graphs of how long each day a worker can be exposed to particular vibration levels. This makes managing the risk relatively straightforward.
Trades Union Congress. Archived from the original on 2013-05-25. –  basic facts
UK Health and Safety Executive
NIOSH Power Tools Sound Power and Vibrations Database
HSE webpage HAV case studies