Exposure to noise in wood chipping operations under the conditions of agro-forestry

An increasing number of agricultural contractors are getting into industrial wood chipping, following the rapid expansion of fiber farms on ex-arable land. Wood chippers are noisy machines and agricultural contractors tend to work long hours, which raises the question about their exposure to noise. The objective of the study was to quantify noise exposure for this occupational group. The Authors selected a representative operation and monitored noise exposure for five full working days, covering the main job types typically encountered in agro-forestry. Noise exposure was highest during chipping time, with 81.8 dB(A). The main source of noise was the powerful diesel engine, followed by the chipper drum: they generated the highest noise levels in the 100-200 Hz and the 20-50 Hz frequency ranges, respectively. Daily noise exposure did not exceed the 80 dB(A) lower action value, and it was similar to the exposure of other workers operating industrial in-wood chippers. However, future optimization measures may lead to increasing the proportion of total time when the machine is under full load, and it generates the highest noise levels. Modeling exposure as a function of efficiency showed that exposure levels may exceed the lower action values, once utilization will increase above 64%. This is a realistic target, which may be achieved in the near future. Fortunately, the problem will materialize only with some specific operation types, which represent a minor component in the wood basket of agro-forestry chipping companies. (C) 2015 Elsevier B.V. All rights reserved.