Journal of Health and Safety at Work

Introduction: Tractor drivers are continuously exposed to whole body vibration during driving that, this may cause disorders in the system of musculoskeletal, nervous, circulatory and occupational diseases. The aim of this study was to evaluate exposed to whole body vibration among tractor driver.

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Material and Method: In this study, whole-body vibration parameters such as root mean square (rms) of acceleration , total equivalent acceleration, vibration dose value (VDV) and crest factor (CF) were separately compared in three directions (x, y, and z) , in 3 Massey Ferguson Model 165 Tractor it was done during 3 different modes of transport (without trailer, with empty trailer and with a trailer load of soil) , plowing the land and loading trailer in working conditions with various gear according to the guidelines of ISO 2631 standard.

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Result: The results showed that in all measuring points, exposure to whole body vibration was higher than permissible level and the risks of disorders exist. Exposure to vibration were as with empty trailer (43.11m/s2). The maximum of crest factor was obtained for transportation mode of empty trailer with 3 gear (10.7), then plowing (7.35) and loading soil(6.50). The maximum of vibration dose value was eventuated for transportation mode with empty trailer with 4 gear (189.92 m/s1.75) and 3 gear (108.15m/s1.75). In all measuring modes exposure with vibration in Y direction was greater than X and Z axes.

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Conclusion: This study shows that the need to provide intervention , controlling and managing measures to eliminate or reduce exposure to whole body vibration among tractor drivers its necessary. And, preventing main disorder Including musculoskeletal disorders, discomfort and early fatigue is of circular importance. More studies are also necessary to identify the sources of vibration among various of tractors.

Introduction: The most common standards being used for predicting the health risks of whole body vibrations are ISO 2631- and BS 6844, presenting frequency weighting anfd different coefficients for different sensivities in variuse axes. In yhis study, vibration was measured about 900 minutes on 9 trains in one of the active lines of tehran metro with the aim of comparing the mentioned standards in evaluating whole body vibation.

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Material and Method: In this research, in addition to evaluation of different kinds of vibration indicators, the differences of ISO 26331-1 and BS 6841 Standards have also been investigated. The amounts of r.m.s., vibration dose and daily vibration dose were measured in x, y and z axes for drivers seat and x axis for drivers back rest separately according to the instruction of the two standards.

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Result: The mean calculated values of r.m.s and vibration dose on a basis of 135 6841 standard were lower than those values calculated according to ISO 2631 standard. Moreover, the results showed that 3 cases, based on the ISO standard, had risk level of higher than 17 m/s1.75 and 3 cases, had risk level of higher than 15 m/s1.75 value, provided by BS 6841.

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Conclusion: Calculation according to the ISO 2631-1 standard show higher values. Indeed, ISO 2631-1 can provide a more secure criterion company to BS 6841, although the 15 m/s1.75 in BS is lower than the highest level of health guidance caution zone in ISO. Additionally, the association between r.m.s and vibration dose values in ISO 2631 is relatively lower than this association in BS 6841.