Because it is friday, Exposure to hand arm vibration is like units of alcohol, the govenment has recommended levels above which regular consumption / exposure can cause long term health effects. The EAV is like the drink drive limit (you or your employer has obligations and responsibilities if you go over this limit - dont drink & drive, or in this case provide health surveilance). The limit value is the point when you become intoxicated or consume your daily recommended amount of units. Over this point there could be health effects. Regularly consuming too much alcohol / vibration does not give your body (liver for alcohol, fingers and blood vessels for vibration) time to record and repair. Binge drinking and consuming all your units in one night is not recommended, nor is exceeding the ELV but can be done if you expect to have the morning off (or no further vibration exposure for the rest of the week) Des