Sound Insulation of Acoustic Louvres and Open Screens

This paper reviews the problem of measuring sound insulation of acoustic louvres and other open screens. A survey of manufacturers in the UK shows that there is little agreement on a test method and performance data is often provided using several indices. The most commonly used method, ISO 140, is inappropriate for acoustic devices with transmission losses of 15dB or less. A review is given of the terminology and methods of measurement used, other non-standard methods are considered and a more suitable method, using impulse response techniques, is proposed. This method does not require special acoustic facilities. Results obtained by impulse methods are compared with standard reverberant room measurements and for screens offering more than 15dB insulation the agreement is promising.