Of Some Hand-Operated Small Machines

Impact evaluation on the operator of some hand-operated small machines

D. Pessina1, A. Calcante1, D. Facchinetti1, D. Giordano1, D. Monarca2, M. Cecchini2,

1 DiSAA - Dipartimento di Scienze Agrarie e Ambientali - Produzione, Territorio, Agroenergia, Università degli Studi 2 DAFNE - Dipartimento di Scienze e Tecnologie per l’Agricoltura, le Foreste, la Natura e l’Energia, Università della Tuscia

Presenting author: [email protected] v. Celoria 2 – 20133 Milan ph. +39 02 503 16876 fax +39 02 503 16845

In addition to safety, it is well known that the hand-operated small machines involve some criticisms also for ergonomics, regarding especially high levels of noise and vibrations. More recently, attention was devoted also to the exhaust gas emissions. On the other hand, all these parameters, as well as the climatic conditions, the workload and other several factors contribute to make quite poor the operators’ wellness, so that a multifactorial approach could probably offer a good evaluation of the real working conditions. The paper deals with the technical progress about gas emission, noise and vibration levels measured on several modern models of chain saws, hedge trimmers and blowers. The experimental data were recorded in 4 different running conditions: with the engine at min, absolute max and max power speed with no load, and when executing a standardized work cycle. Moreover, in order to ascertain in particular the exhaust gas emission impact, the tests were repeated using two different fuel types: a commercial RON 95 gasoline added with a 2% of synthetic oil suitable for two-stroke engines and, as an alternative, a specific advanced mixture available on the market, based on alkylate gasoline. To evaluate the improvement in working conditions, new models compliant to Stage 2 of the exhaust gas emission Standard and old models exceeding these limits were compared in terms of gas and noise emissions and vibration levels. In all the operating conditions, the tests were carried out: 1) for the noise, using a class 1 sound level meter, to record the levels at both the operator’s ears, taking into account the limits defined in EN 22868:2011; 2) for vibrations, using a tri-axial accelerometer fixed on the machine following what established in the ISO 5349-1:2001, and evaluating the overall value (ahw) by calculation from the single axes x, y and z, then referred at the normalized 8- hours A(8) exposure (EN22867:2011); 3) for gas emissions, using a MultiRAE IR/PID mod. PGM 54/5P analyzer, for measuring carbon monoxide and dioxide (CO and CO2), and volatile organic compounds (VOC) values.