Noise classes for the outdoor machines subject to noise limits

One of the main targets of the Directive 2000/14/EC is to inform and educate consumers by providing meaningful information on the noise emissions and then encouraging the choice of quieter equipment. Information on noise emissions are currently provided by a mandatory noise emission marking that shows the guaranteed sound power level. This label, however, has proven to be inadequate for the defined target due not only to the difficulties in interpreting the given information in decibel but also to the limitation of information given by the label itself. The only knowledge of the guaranteed sound power level is meaningless as it does not explain how noisy a given product is compared to similar ones. The assessment of this comparative information requires the definition of a certain number of noise classes ranging from the lowest noise emission to the highest one. In a previous paper authors defined a statistical procedure able to cluster the declared sound power levels into three classes. This study aims at analysing in more detail this procedure when applied to the outdoor equipment subject to noise limit and different possible criteria driving the definition of noise classes are considered in light of several important aspects. An extract of the EU NOISE database containing the declared guaranteed sound power levels in the period 2006-2015 was used for this purpose. A further selection of the data was performed in order to exclude all the erroneous and incomplete data. Unfortunately, the application of this procedure to the revised database brings to the result that the procedure is applicable only in three cases. In all the other cases, the criterion that no more than 30% of the available data is assigned to the noisiest class is not fulfilled. Therefore, new and reasonably consistent criteria are proposed for the noise data clustering process.

L'etichettatura che è stata prevista con la Direttiva 2000/14/CE non è stata in grado di attivitare una maggior sensibilizzazione nei confronti del rumore. Nel tentativo di ridisegnare questa etichetta, è stata applicata una procedura di suddivisione del prodotto in funzione di 3 classi di rumore come suggerito dalla ISO 11689:1996. Questa procedura è stata applicata a tutte le 22 macchine soggette a limiti ma solo in 3 casi i criteri sono stati rispettati. Per la restante parte di macchine, i livelli di potenza garantita sono talmente vicini al limite previsto che non è mai rispettato il criterio di avere al massimo il 30% dei dati nella classe più rumorosa.