Road traffic noise reducing devices - Test method for determining the acoustic performance - Part 2: Intrinsic characteristics of airborne sound insulation under diffuse sound field conditions

This document describes a test method for measuring a quantity representative of the intrinsic characteristics of airborne sound insulation for traffic noise reducing devices: the sound insulation index. The test method is intended for the following applications: - determination of the intrinsic characteristics of airborne sound insulation of noise reducing devices to be installed along roads, to be measured either in situ or in laboratory conditions; - determination of the in situ intrinsic characteristics of airborne sound insulation of noise reducing devices in actual use; - comparison of design specifications with actual performance data after the completion of the construction work; - verification of the long term performance of noise reducing devices (with a repeated application of the method); - interactive design process of new products, including the formulation of installation manuals.