ÖNORM EN ISO 9614-2

1.1 This part of IS0 9614 specifies a method for measuring the component of sound intensity normal to a measurement surface which is chosen so as to enclose the noise source(s) of which the sound power level is to be determined. Surface integration of the intensity component normal to the measurement surface is approximated by subdividing the measurement surface into contiguous segments, and scanning the intensity probe over each segment along a continuous path which covers the extent of the segment. The measurement instrument determines the average normal intensity component and averaged squared sound pressure over the duration of each scan. The scanning operation may be performed either manually or by means of a mechanical system. Band-limited weighted sound power level is calculated from the measured octave or one-third-octave band values. The method is applicable to any source for which a physically stationary measurement surface can be defined, and on which the noises generated by the source under test and by other significant extraneous sources are stationary in time, as defined in 3.13. The source is defined by the choice of measurement surface. The method is applicable in situ, or in special-purpose test environments. This part of IS0 9614 specifies certain ancillary procedures described in annex B, to be followed in conjunction with the sound power determination. The results are used to indicate the quality of the determination, and hence the grade of accuracy. If the indicated quality of the determination does not meet the requirements of this part of IS0 9614, the test procedure is to be modified in the manner indicated. This part of IS0 9614 does not apply in any frequency band in which the sound power of the source is found to be negative on measurement. 1.2 This part of IS0 9614 is applicable to sources situated in any environment which is neither so variable in ti (...abbreviated)