In arrivo tre nuove norme europee sulle barriere antirumore

The European package on road traffic noise reducing devices has recently been updated with three new standards. The main improvement of EN 1793-1:2013 is the introduction of a correction for air sound absorption due to temperature and humidity changes during tests in a reverberation room. This may change the measured sound absorption values, especially at high frequencies; the single number rating DLalpha may change of 1-2 dB in the positive or negative sense. This standard assumes a diffuse sound field. Also, a new category A5 for strongly sound absorbing products is introduced. The main improvement of EN 1793-2:2013 is the acknowledgement of the fact that the results of this laboratory test are applicable only to products to be installed in a reverberant sound field. Also, a new category B4 for strongly sound insulating products is introduced. EN 1793-6:2013 is a brand new standard replacing the second part (airborne sound insulation) of CEN/TS 1793-5:2003. The latter introduced the new in situ methodology developed during the European project ADRIENNE. The new EN 1793-6:2013 includes the improvements developed during the recent European project QUIESST (2009-2012). This method can be applied on free standing noise barrier on the site where the noise barrier is installed, i.e. along roads; it may also be applied on prototypes built near a laboratory or the manufacturer’s factory. It can be applied to non flat devices or to devices composed of different materials. This robust method has been validated by eight European laboratories during an inter-laboratory test, which also gave the repeatability and reproducibility values. The repeated application of the method permits to assess the trend of the intrinsic acoustic characteristics of a noise reducing device with time.