Risk exposure to vibration and noise in the use of tracklay- ing tractors

Human exposure to mechanical vibration may represent a significant risk factor for exposed workers in the agricultural sector, with particular reference to the operators driving tractors. Also noise in agriculture is one of the risk factors to be taken into account for the evaluation of workers health and safety. In particular, one of the major sources of discomfort for the workers operating a tractor is the noise to which they are subjected during work. In Italy, Law Decree 81/2008 has defined the obligations of vibration and noise assessment and risk management.The aim of this study is to evaluate the risk of exposure to whole-body vibration for the operator driving a tracklaying tractor working in vineyard orchard and the noise level close to the ear of the operator driving the tractor. The experimental tests were performed using six different tracklaying tractors, 40-51 kW power, coupled with the same rototilling machine model BF160 by Celli (Forlì, Italy).For the evaluation of whole-body vibration we referred to ISO 2631-1:2008 standard. The tests for noise evaluation were performed in compliance with the standards ISO 9612 and ISO 9432.During the tests we used the portable vibration analyzer HD2070 by Delta OHM, Italy, that is able to perform spectral analysis and statistics simultaneously on three channels, and a precision integrating portable sound level meter, class 1, model HD2110L by Delta OHM, Italy. The mean square frequencyweighted acceleration was evaluated along each of the three axial components of the acceleration vector (awx, awy, awz) and the total vibration value. The sound level meter measured Aweighted time-averaged sound pressure level (LAeq) and C-weighted peak sound pressure level (LCpk).This study allowed us to point out that in the use of tracklaying tractors coupled to a rototilling machine, the vibration values referred to the 8-hour working day were always higher than 0.5 m s and, therefore, included in the "risk threshold" identified by Italian Law Decree 81/2008. With reference to noise assessment, the daily noise exposure levels obtained by rototilling always overcome the exposure limit value of 87 dB(A) according to the above mentioned law.