DIN EN ISO 11204:2010-10

The standards DIN EN ISO 11201, DIN EN ISO 11202 and DIN EN ISO 11204 specify methods for measuring emission sound pressure levels at a work station and at other well defined positions, in the vicinity of a machine or piece of equipment. With the method specified in DIN EN ISO 11201 - depending on the degree of compliance with the given requirements on background noise and the test environment - results of accuracy grade 1 (precision grade) or accuracy grade 2 (engineering grade) are obtained. Precision measurements with accuracy grade 1 can generally be carried out in hemi-anechoic test rooms or outdoors provided that requirements of environmental conditions are met. Measurements with accuracy grade 2 can also be carried out (in situ) at typical application areas of the machinery or equipment; they are included with the intention that they also meet the requirements of the previous editions, DIN EN ISO 11201 (1996-07 and 2009-11). The described method differs from the methods in both standards DIN EN ISO 11202 and DIN EN ISO 11204 in not applying any environmental correction. With the method specified in DIN EN ISO 11202 - depending on the degree of compliance with the given requirements on background noise and the test environment - results of accuracy grade 2 (engineering grade) or accuracy grade 3 (survey grade) are obtained. Measurements can be carried out in the immediate vicinity (in situ) of the machinery or the equipment. The described method differs from the method specified in DIN EN ISO 11201 in determining and applying a local environmental correction. It differs from the method specified in DIN EN ISO 11204 by using an approximate method to determine the directivity of the sound radiation of the machine under test with a reduced number of measurement positions or even with no additional measurement. The acoustical properties of the room shall be determined to qualify the test environment and to determine a correction value for local environmental influences which shall be applied to the measured sound pressure levels. With the method specified in DIN EN ISO 11204 - depending on the degree of compliance with the given requirements on background noise and the test environment - results of accuracy grade 2 or accuracy grade 3 are obtained. Measurements can be carried out in the immediate vicinity (in situ) of the machinery or the equipment. The described method differs from the method specified in DIN EN ISO 11201 in determining and applying a local environmental correction. It differs from the method described in DIN EN ISO 11202 by using an exact measurement to determine the directivity of the sound radiation of the machine under test from sound pressure level measurements on a reference measurement surface. The three standards are revisions of the corresponding standards which were published in 1996 and 2009, respectively. Apart from the further developments of the measuring procedures described above, criteria for background noise have been supplemented by an absolute criterion; a conversion of the emission sound pressure levels to meteorological reference conditions in dependence on the accuracy grade has been specified; the clause on measurement uncertainty has been completely revised and an annex on guidance on the development of information on measurement uncertainty has been incorporated. The International Standards on which this standard is based have been prepared by ISO/TC 43/SC 1/WG 28 "Basic machinery noise emission standards", with the German collaboration of Working Committee 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.