The Effectiveness of Insulation Measures Against Traffic Noise

Since 1973 the UK has had regulations which require that a noise insulation package is installed in dwellings subjected to high levels of noise from new or modified roads.The Building Research Station have carried out an investigation into the effectiveness of the package and its acceptability to residents.To provide data on the effectiveness of the package, noise insulation measure ments over a frequency range 31.5 Hz to 3l50 Hz were made on more than ISO installations which had been treated under the Noise Insulation Regulations.A questionnaire survey was used to determine the attitudes of 900 residents to the package.The questionnaire sought their responses as to the effectiveness of each component of the package and the acceptability of the resulting acoustic, thermal and ventilation conditions in the dwelling.The average noise reduction of a treated facade was found to be 34 dB(A) and, overall, the package of insulation measures was considered satisfsctory by 841 of respondents.The measured performance of the package is described including spectral information, variability of performance and comparison with the noise insulation of untreated facades.Details of the results from the subjective study are discussed showing how effective the respondents consider the package to be at providing an acceptable indoor environment and how the level of response varies with external noise level.