Hand-Arm vibration assessment among tiller operator

The power tiller is a multipurpose hand tractor designed primarily for rotary tilling and other farm operations. Vibration، transmitted from the handles of the tiller to the operators’ body، causes many injuries such as، pain، musculoskeletal disorders and white finger syndrome. The aim of this study was to evaluate the hand-arm vibration exposure in the operators of tiller model HT900، as the most frequently used model of tillers. In this study، 40 operators tiller of model HT900 in the city of Kashmar، Khorasan Razavi were examined. Hand-arm vibration measurement was done according to ISO 5349-1 and ISO 5349-2 in three different modes including، static and neutral (mode)، transition to the ground mode and plowing the land mode in different gears. In order to measure the vibrations، human response vibration meter of B and K model 2512 was utilized. Results of the present study indicated that in all measured situations، exposure to hand arm vibration was higher than the standard limit suggested by Iranian occupational health committee and there was risk of vibration-induced disorders. The maximum exposure to vibration is in plowing ground. Exposure to hand arm vibration in three modes of plowing، transmission and natural، were respectively 16. 95، 14. 16 and 8. 65 meters per second squared. Additionally، in all situations، vibration exposure was highest in the X-axis in comparison with Z- and Y-axes. This study emphasizes on the need to provide intervention and controlling and managing strategies in order to eliminate or reduce vibration transmitted from tiller to operators hand and arm and also prevent to serious problems including neurovascular disorders، discomfort and white finger syndrome. Meanwhile، more studies are necessary to identify the sources of vibration on different models of tiller.