Paragraph 7.3.1 Detection of noise of an impulsive character

Comparison of the readings on a precision sound level meter set at ‘slow’ response with those of a precision impulse sound level meter set at ‘impulsive’ response (IEC Publication 651, first edition, 1979) allows an assessment to be made of whether or not a noise is of an impulsive character. According to this measurement procedure, the difference between the root mean square values in time of the sound pressure levels measured with the sound level meter at slow and impulsive response respectively is taken as an indication of the impulsive character of a noise. The sound pressure level obtained with the ‘impulsive’ response is referred to as the ‘impulsive sound pressure level’.

This shall be determined at one of the measuring points laid down.

A noise is considered to be impulsive in character if the difference between the two above-mentioned levels is greater than or equal to 4 dB.