The principle of the method consists in determining the equivalent continuous 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 equivalent continuous A-weighted sound pressure levels over subintervals within T where 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 during the time interval T, LAeqT being obtained by calculation based on the results of these measurements;
- by combining the methods presented above.
Measurements are performed in the field, and determinations can be completed with calculation steps, including the use of validated specific software. Sampling may be performed continuously over the time period of interest or sampling methods may be used. The laboratory, in addition to LAeqT, may also measure and report other acoustic indicators considered useful for the characterization of noise pollution (LAFmax, LAF90T, etc.).