Abstract

In response to a request by the Association de sécurité des exploitations forestières du Québec (Québec Forestry Sector Safety Association) and by industrial hygienists, the IRSST evaluated the skidder operator workstation, at which significant whole-body vibration may arise during the movement of the vehicle over irregular terrain. The project objectives were the evaluation of vibration levels to which operators are exposed, and the development of a measurement and analytical technique based on ISO standard 2631/1, and of more effective corrective measures for operators.

Information on the characteristics of each skidder was gathered by means of questionnaires, and a FM telemetry system was developed to collect vibration data from the vehicles. For the observed daily exposure period of 5 hours, the results indicate overexposure (as defined by ISO standard 2631/1) to vibration in the front-back (longitudinal) and left-right (lateral) axes, and a high level of up-down (vertical) vibration. The rigid seats with which most of the skidders are equipped only attenuate vibration at frequencies higher than those to which humans are most sensitive. A feasibility study of the use of passive-suspension seats to reduce operator exposure to vibration was subsequently performed.