scope:

This International Standard specifies a survey method for measuring the sound pressure levels produced at specified measurement points by the noise source under test and by a reference sound source.The sound power level of the source under test is calculated from the measured values of the sound pressure level by using environmental corrections. These environmental corrections are calculated from the differences between the values obtained with a reference sound source and those given by its calibration. Different microphone arrays and different positions for the reference sound source are given for different acoustical situations, depending on the size of the source under test as well as the size, number and orientation of the reflecting planes which are situated in proximity to the source under test. The positions of the reference sound source also depend on whether it is possible to place the reference sound source on the uppermost outer surface of the source under test. This International Standard applies to sources which radiate broad-band noise, narrow-band noise, discrete tones and combinations thereof. The procedures specified in this International Standard are primarily applicable to sources that radiate steady noise as defined in ISO 2204. These procedures are not applicable to isolated bursts of sound energy or burst trains with repetition rates less than 5 per second. The method specified in this Internation Standard applies to noise sources irrespective of size. It applies particularly to machines and equipment which cannot be moved from their installed location for the purposes of measuring noise.