出版社：National Institute of Occupational Safety and Health
摘要：In order to determine a criterion of VL value of a vibration level meter used for the measurement of environmental vibrations, experiments for long time exposure from 2 to 4 hr to vibrations was carried out on ten subjects. Vibrations of a diesel pile driver and a forklift were adopted as the sample vibrations. Response to these vibrations were studied on several psychological and physiological parameters. Changes in such parameters as sequent subjective judgement, equivalent level and threshold shift were found significant in relation to exposure time, though it was somewhat difficult to estimate the criterion of VL value from the interrelation between these parameters. The criterion of VL value was estimated from the subjective judgement alone as follows: 95 dBVL to 3 hr, 100 dBVL to 1.5 hr and 103 dBVL to 1 hr to be permitted for exposure. These levels showed perception lying between unpleasant and slightly unpleasant feeling in a five grade judgement and agreed with the criterion curves of fatigue decreased proficiency boundary (FDP) proposed in DIS-2631 of ISO/TC 108/SC 4.
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