DIN EN ISO 3746:2011-03

This standard describes methods of accuracy grade 3 (survey grade) for determining the sound power level and sound energy level of a noise source (machinery or equipment) from sound pressure levels measured on a surface enveloping a noise source. For this purpose, the noise source shall be mounted on one - and in front of more, if relevant - sound-reflecting surface(s). Requirements are specified, amongst other things, for the test environment, instrumentation, measurement surfaces and installation and operation of the noise source under test. The annexes describe methods for the determination of the environmental correction and for microphone arrays on the various measurement surfaces. Another annex contains a guideline on the development of information on measurement uncertainty. The most important alterations with respect to the 2009 edition of the standard are as follows: a) determination of sound energy levels has been added; b) treatment of measurement uncertainty has been extended and approach in accordance with the GUM Guide has been added; c) annex on qualification procedures for the acoustic environment has been reduced to a simple method (estimation method) for the determination of the environmental correction; d) specifications about microphone arrays on a quarter hemispherical measurement surface (position of the noise source in a corner) have been added; e) annex on the detection of impulsive noise has been deleted; f) annex with a guideline on the development of information on measurement uncertainty has been added; g) standard has been completely editorially revised. The international standard on which this standard is based has been prepared by Working Group 28 "Basic machinery noise emission standards" of ISO/TC 43/SC 1 "Noise" with German participation. On the European level, the standard exists within the framework of CEN/TC 211 "Acoustics". Regarding German cooperation, the responsible Working Committee is NA 001-01-04 AA "Geräuschemission von Maschinen und Anlagen; Messung, Minderung, Datensammlung" ("Noise emission of machines and plants: measurement, reduction, data collection") of NALS.