Recent advances in noise barrier testing, qualifying and standardisation (invited plenary lecture)

The standardization activity inside CEN (European Standardization Committee) is giving an important contribution to the definition of the technical characteristics of noise barriers; 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 tuned versions of the ISO 354 and ISO 140-3 ones. The same properties can also be measured in a direct sound field, e.g. in situ on installed noise barriers, thanks to a new method based on an impulsive technique with the use of a MLS 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 together with real life results. Other standards dealing with products specifications, long term performances, and non-acoustic performances (like fire reaction and fatigue due to dynamic loads) will be briefly presented as they concern how to keep noise barriers and related devices performing correctly for many years. Overall, the European qualification system for noise barriers and related devices could be considered the most advanced in the world.