The principle of the method consists in determining the continuous equivalent A-weighted sound pressure level (LAeqT) using a class 1 integrating-averaging sound level meter. The determination of LAeqT can be performed:
- by continuous measurement over the time interval T;
- by measuring the continuous equivalent A-weighted sound pressure levels over subintervals of time within T, in which the noise is stationary, LAeqT being obtained by calculation based on the results of these measurements;
- by measuring the acoustic exposure levels of individual events occurring over the time interval T, LAeqT being obtained by calculation based on the results of these measurements;
- by combining the above-mentioned methods.
Measurements are carried out in the field, the determinations being able to be supplemented with calculation stages, including the use of validated specific software. Sampling can be performed continuously over the period of interest or sampling methods can be used. In addition to LAeqT, the laboratory can also measure and report other acoustic indicators considered useful for characterizing noise pollution (LAFmax, LAF90T, etc.).