Níveis de ruídos em operações agrícolas

Abstract

This study was conducted in private property, located on the city of Pato Branco, Paraná, Brazil, in order to evaluate the noise levels emitted by two tractors (with and without cabins) in different agricultural operations. For the measurement of the noise emitted by the tractors, a digital decibelimeter of the brand ICEL, model DL-4200, was used in the fast response circuit and equalization "A" near the operator and "C" for the machines. A sample mesh was made for a square space of 30 meters on the side, positioning the tractor in the middle of this plane and, later, points were marked every 3 meters of the tractor. The crossing of the lines determined the collection points, totaling 121 points. The following machines were used: New Holland TL75 tractor, 75 hp, year 2013, with cab; Tractor Valtra BM110, 110 hp, year 2005, without cab; Cereal beater; Bar sprayer Jacto. During the evaluations, both tractors worked with a constant rotation of 2200 rpm, with a rotation of 540 rpm in the Power Takeoff (TDP). The readings of the noises emitted by the tractors were made for a period of 5 seconds for each evaluation point, next to the operator and in the 4 directions, totaling 126 noise samples for each operation. The sets of machines were denominated like: TCP - tractor with cabin plus sprayer of bars; TCB - tractor with cabin plus cereal beater; TSP - tractor without cab plus sprayer of bars; TSB - tractor without cabine plus cereal beater. The evaluation of the noise emitted by the sets was carried out by weighing the average of the samplings taken by the decibelimeter during the predetermined time of 5 seconds. Dispersion graphs were generated by interpolating the collected data. The sets with the cab tractor showed lower noise levels in relation to the operating station, within the limits set forth in the regulations. The sets with the tractor without cabin had high levels of noise, almost always above those accepted in the regulations, causing discomfort and could cause hearing losses to the operator if exposed for more than 8 hours without the use of the appropriate PPEs.