Resumen de Noise levels of a Massey Fergusson 285 tractor during movement on dirt and paved roads
M.R Ghotbi Ravandi, M.R. Monazzam, N. Khanjani, S Momen Bellah Fard, H. Nadir, F. Nadri
This study aimed to determine the noise levels of a Massey Fergusson 285 tractor during movement on dirt and paved roads. The Massey Fergusson 285, 75 hp tractor accompanied by a trailer with one-ton load travelled on dirt and paved roads. The test field had 20 m length and 3 m width as defined according to international standards. The sound levels were measured with different gears and for engine speeds of 1000 and 2000 rpm at bystander position and right ear of operator. The difference between A-weighted sound levels for bystanders and right ear of operator, in engine speed of 1000 for dirt and paved roads, was 13.7-15.9 and 10.9-14.7 dB and, in engine speed of 2000, was 12.7-16.1 and 9.8-13.8 dB, respectively. In the bystander position, the sound levels for both engine speeds were lower on the dirt road compared to the paved road. The sound level at the right ear of the operator at engine speed of 1000 rpm was lower than ACGIH standards (85 dB whereas it was higher in engine speed of 2000 rpm for both roads, except in first low and first high gears on the dirt road. Based on similar distance for measurement points on both roads, the lower acoustic impedance of dirt compared with pavement surface provides less noise reflection which leads to lower noise levels in bystander position. The farmers who work near dirt roads are exposed to lower sound levels than those working near paved roads.
