scope:

This European Standard describes a test method for measuring aquantity representative of the intrinsic characteristics of soundreflection from road noise reducing devices: the reflection index.The test method is intended for the following applications: ?determination of the intrinsic characteristics of sound reflectionof noise reducing devices to be installed along roads, to bemeasured either on typical installations alongside roads or on arelevant sample section; ? determination of the in situ intrinsiccharacteristics of sound reflection of noise reducing devices inactual use; ? comparison of design specifications with actualperformance 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). The test method is notintended for the following applications: ? determination of theintrinsic characteristics of sound reflection of noise reducingdevices to be installed in reverberant conditions, e.g. insidetunnels or deep trenches. Results are expressed as a function offrequency, in one-third octave bands between 100 Hz and 5 kHz. Ifit is not possible to get valid measurements results over the wholefrequency range indicated, the results should be given in arestricted frequency range and the reasons of the restriction(s)should be clearly reported.