- Report #: NT ACOU 104
- Approved: November 1999
This NORDTEST method specifies a procedure for the determination of the normalised specific acoustic impedance of flat outdoor ground surfaces in situ. It yields one or several flow resistivity classes the values of which can be translated into the real and imaginary part of the specific acoustic impedance to use for outdoor sound propagation calculations. This NORDTEST method is not suitable for the evaluation of ground impedances below 200 Hz or above 2500 Hz.