Contact force is a measurement of the amount of force between a user’s hand and the tool they’re using. The SV103A personal vibration dosimeter and the SV106A (when used with the SV105AF transducer) are unique in that they measure contact force, which ensures any uncertainty of the measurement to be greatly reduced. You can choose to disregard any data where there is insufficient contact force.
The new dosemeter standard ISO8041-2, under preparation and until recently chaired by Paul Pitts of HSL, will specify a new class of instrument called a Personal Vibration Exposure Meter, which will require contact force measurement. Svantek have the only instruments which currently meets the draft standard, and the SV103A and SV106A are the only ones on the market for now.