This International Standard specifies an engineering method (grade 2, as defined in ISO 2204) for determining the sound power levels of large multisource industrial plants relevant to the evaluation of sound pressure levels in the environment. These sound power levels may be used in an appropriate prediction model for such an evaluation.

The method is limited to large industrial plants with multiple noise sources (a combination of an unspecified number of individual sources) having their main dimensions in the horizontal plane, and which radiate

Unweighted sound pressure levels are measured in octave bands.

The results obtained are expressed both in octave band sound power levels and, if required, in A-weighted sound power levels.