The sensation of intensity and comfort or discomfort caused by whole-body vibration depends on the vibration frequency, the point of exposure and its direction. The findings were obtained in laboratory experimental studies with rigid seats and upright posture. They serve as a basis for frequency weighting curves and multiplying factors established in ISO 2631-1 (1997). The standard separates the evaluation of vibration exposure concerning the sensation of comfort and relating to "health", in particular with regard to the musculo-sceletal system. At present, ISO 2631-1 is under critical discussion. New investigations suggest that the frequency dependent sensation of comfort alters with the vibration magnitude. That is not taken into account in the current evaluation methods. Additionally, there seems to be an interaction between comfort sensation and posture including the use of the backrest. A potential influence of individually psychological aspects on the sensation of intensity and comfort has not been systematically investigated. Also, the application of findings obtained in investigations of comfort sensations to the criterion 'health' seems not to be sufficiently validated. But, the legal requirements focus on the criterion 'health', not on the comfort sensation. The evaluation methods established in ISO 2631-1 are used for the calculation of the daily vibration exposure value A(8) which has to be compared with the action value and the exposure limit established in European and German Legislation. In this respect, the topic refers to the current risk assessment of whole-body vibration. The study aims at the derivation of an evaluation method which better reflects the subjects' sensation due to vibration than the current method. Moreover, new investigation methods and study designs for the validation of available evaluation methods for the criterion 'health' are expected.
Unit 3.1 "Prevention of Work-related Diseases"