Noise level emitted by mechanized groups as a function of speed and soil condition

Abstract

The noise generated by agricultural mechanization has brought side effects, and one of them is the damage to the hearing of agricultural machinery operators. According to NR-15, which establishes the tolerance limits for continuous noise, the exposure to noise levels above 115 dB (A) for individuals who are not adequately protected is not permitted, given that the maximum tolerable limit, considering an 8-hour working day, is 85 dB (A). The objective of this work was to study the influence of the travel speed and soil condition on the determination of sound power levels emitted by the tractor in several agricultural operations. The study was conducted at the Campus of Agricultural Sciences of Universidade Federal do Vale do São Francisco, Petrolina, Pernambuco, Brazil, using a Valtra tractor model 785 TDA without cabin and a noise level meter. The sound power level of the tractor was evaluated in five speeds (0.83; 1.39; 2.42; 2.97 and 3.61 m s^-1) on prepared soil and soil covered with weeds, with the machinery: tractor (control), off-set disk harrow, chisel plow and rotary mower. Data were analyzed by polynomial regression when significant at least 5% probability by the F test. The most significant values were found in the tractor and plowing, observing that the need for higher engine power increased the sound power level. The other operations had noise values above the sound power established by the NR-15, considering the 8-hour working day.