COMPARISON OF DIFFERENT MEASURES FOR HAND-ARM VIBRATION EXPOSURE

Vibration measurements have been done on hand-held tools in a group of 48 platers by evaluating the individual vibration acceleration and ab sorption of vibration energy. The measurement of the acceleration has been done frequency-weighted and frequency-unweighted in accordance wi th ISO 5349 and NIOSH (USA) recommendations for hand-arm vibration sta ndards, respectively. The acceleration and the energy absorption have been measured simultaneously in the three orthogonal directions, the l atter by using a specially designed adapter. The exposure time has bee n determined by both subjective assessments and objective measurements . Individual energy-equivalent accelerations and vibration dosages hav e been calculated from these data. The results show that the type of t ool was critical to vibration load intensity when the different measur es for determining vibration levels were used. Of the methods used, th e evaluation specified by ISO 5349 makes most consideration of low fre quencies of vibration (< 50 Hz). absorption of vibration energy middle frequencies (50-200 Hz) and NIOSH of high frequencies (> 200 Hz). The results show a poor correlation between the three methods used. The s ame was found between mean subjective assessment and objective measure ment of the average exposure time. Further studies of the relation bet ween results presented here and generated disturbance will be conducte d, which may clarity any exposure-response relationship. (C) 1998 Else vier Science Ltd. All rights reserved.