Recent advances in noise barriers testing, qualifying and standardisation

The standardization activity inside CEN (European Standardization Committee) is giving an important contribution to the definition of the technical characteristics of noise barriers and related devices; new test methods have been purposely developed and validated. Sound absorption and airborne sound insulation in a reverberant sound field (like inside tunnels or deep trenches) are tested in laboratory using optimized versions of the ISO 354 and ISO 140-3 standards. The same properties can also be measured in a direct sound field, e.g. in situ on free standing noise barriers, thanks to a new method based on an impulsive technique with the use of a deterministic test signal. A similar technique can also be applied to characterise sound diffraction of “added devices” which may be placed on the top of noise barriers. The principles of these methods are presented here together with real life results. Other standards dealing with non-acoustic performances (like mechanical resistance and fire reaction) and long term performances will be briefly presented, as they concern how to keep noise barriers and related devices performing correctly for many years. In the rail sector, new standards are in preparation about insertion loss and fatigue from dynamic loads due to passing trains. In the road sector, the existing standards make it possible to prepare a “declaration of conformity” of the device according to the European rules, which authorizes affixing the CE marking on products.