In-situ testing of acoustical properties of noise barriers

The acoustic performance of noise barriers are mainly determined by the insulation and the absorption of the noise barrier. To assure proper working of the noise barrier, contracts demand minimum values for the insulation and absorption. These minimum requirements are determined on test samples in the laboratory. Determination of the insulation and absorption in-situ is hardly ever required.However, in the past years we noticed an increasing interest for in-situ measurements to determine the insulation and absorption of noise barriers. Comparison between the results of laboratory and in-situ measurements is not straight-forward because of the diffuse, omnidirectional sound field in the laboratory and the limited angles of incidence in the field. We conducted an extensive measurement program to compare the results of laboratory and in-situ measurements. The goal of this research is to enable validation of the requirements for lab-based acoustic requirements for insulation and absorption with in-situ measurement results. This will allow the manufacturers to optimize their designs for the best performance in the field. Also, this allows for COP testing and monitoring of the acoustic durability over time.