The document here contains basic information on the EU Directive "Vibrations" (2002/44/EC) and the effect of vibrations on hands and arms, as well as useful information concerning its implementation by employers.
Classification of the risk depends on the specific product and on the equivalent vibration value ahv,eq.
STIHL outlines a simplified procedure here allowing you to judge whether special protective measures are necessary for your employees. The procedure is based on the assumption that the same machine is used constantly throughout a working day.
On this page STIHL offers you a calculator to help you work out the permissible working duration per working day, to calculate the daily vibration load and, alternatively for one or more tools used at the same time.
STIHL power tools are hand tools as defined by the Directive and the Directive sets a limit on the daily vibration stress resulting from their use. You can find the relevant vibration data for STIHL machines in the following documents.