This document specifies a test method for measuring a quantity representative of the intrinsic characteristics of airborne sound insulation for road traffic noise reducing devices: the sound insulation index.
This document is applicable to:
— determination of the intrinsic characteristics of airborne sound insulation of noise reducing devices to be installed along roads, to be measured either on typical installations alongside roads or in laboratory conditions;
— determination of the intrinsic characteristics of airborne sound insulation of road traffic 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 road traffic noise reducing devices (with a repeated application of the method);
— interactive design process of new products, including the formulation of installation manuals.
This document does not apply to:
— the determination of the intrinsic characteristics of airborne sound insulation of road traffic noise reducing devices to be installed in reverberant conditions, e.g. inside tunnels or deep trenches or under covers.
Results for the sound insulation index are expressed as a function of frequency in one-third octave bands, between 200 Hz and 5 kHz for qualification purposes. If it is not possible to get valid measurement results over the whole frequency range indicated, the results are given in a restricted frequency range and the reasons for the restriction(s) are clearly reported.
For indoor measurements, see Annex D.