Noise Reducing Devices: an Austrian Experience with the new European Standard for Measurements of In-Situ Sound Diffraction

Traffic noise is one of the major environmental concerns within the European Union. The most important solution to noise abatement along roads and railways is the construction of noise barriers. In order to measure the acoustic performance in real life conditions and the long-term performance of these devices, the working group CEN/ TC226/ WG6 has developed the so called Adrienne method. This measurement method was introduced in 2003 with the technical specifications CEN/TS 1793-5 [1], dealing with in-situ sound absorption and sound insulation, and CEN/TS 1793-4 [2], dealing with in-situ sound diffraction. Added devices for sound diffraction are becoming more relevant in the last years to increase the acoustic performance of barriers. This paper describes one of the first Austrian research activities dealing with measurements of in-situ sound diffraction based on this Technical Specification. This study, carried out in 2006 by arsenal research, compares the acoustic behaviour of aluminium cassettes, alternately mounted as flat reference barriers, partially non flat products, added devices on the top of the barrier, transparent insertions and digital prints on the surface. In detail, the authors measured and analysed the in-situ acoustic properties sound absorption, sound insulation and sound diffraction of each variant. The research was carried out for the company Forster Metallbau GmbH.