How is vibration measured?

Your daily exposure to vibration is measured by a formula known as an A (8) value. This is the average (A) exposure over an eight-hour (8) day. In the UK, the current values are based on both the following measures:

Vibration magnitude (m/s2)*:  2.8, 5.6, 8, 11.2

Exposure: hours a day:  8 hours, 4 hours, 2 hours, 1 hour, 0.5 hours

* m/s2 is a technical measure of the rate of vibration of a tool or piece of machinery, measuring its movement in meters (m) per second (s). Suppliers must provide information on the vibration emission value of their equipment.

• Current guidance from the Health and Safety Executive recommends that employers take steps to prevent vibration when your exposure regularly exceeds the action level of 2.8 m/s2 A (8) averaged over an eight-hour day. The HSE says that around 1.2 million men and 40,000 women are daily exposed to vibrations above this action level.
• The higher the rate of vibration (the top line in the above list), the shorter the time you should use the tools involved (bottom line).