|Riassunto in Inglese:|
In agriculture, some professional farm machineries are utilised in an intensive
way for long periods. Italian law considers these machines as a place of work
and risk evaluation is necessary before their use.
In this paper the exposure of the operator to noise is examined in accordance
with the italian law D.Lgs. 277/91 (acknowledging 80/1107/EEC, 86/188/EEC,
88642/EEC) in comparison with the new directive 2003/10/CE.
The noise emissions of two self-propelled lawn mowers, with on-board drivers
(ride-on), have been measured in normal operating conditions.
The machines were equipped with two different engines and two cutting desks,
for a total of 4 experimental thesis.
The instruments were from Brüel & Kjær and constituted by a microphone
(type 4189), a modular precision sound analyzer (type 2260) and an acoustic
calibrator (type 4231).
Through such values it has been possible to calculate, in each thesis, the daily
maximum exposure duration of the operator to noise in correspondence of the
limit values outlined by the cited directives. The reduction of the maximum
limits of noise level, from 90 dB(A) to 87 dB(A), directly affects the maximum duration of daily operator exposure to noise.
The application of the new directive 2003/10/EC determines the necessary
halving of the exposure time to noise.
The tests results show that the measured noise levels exceed the law
limitations, as verified in all the theses.
Consequently the time range reduction from 2h up to 2h 45’, strongly reduces
the possibility of professional use of the tested lawn mowers, as planned in the
respect of the previous law.