DIN EN ISO 7779:2011-01

This standard specifies procedures for measuring and reporting the noise emission of information technology and telecommunications equipment. The basic emission quantity is the A-weighted sound power level which may be used for comparing equipment of the same type but from different manufacturers, and for comparing different equipment. Three basic noise emission standards for determination of the sound power levels are specified in order to avoid undue restriction on existing facilities and experience. DIN EN ISO 3741 describes comparison measurements in a reverberation test room; DIN EN ISO 3744 and DIN EN ISO 3745 describe measurements in an essentially free field over a reflecting plane. Any one of these three basic noise emission standards can be selected and used exclusively in accordance with this standard when determining sound power levels of a machine. The A-weighted sound power level is supplemented by the A-weighted emission sound pressure level determined at the operator position(s) or the bystander positions, based on basic noise emission standard DIN EN ISO 11201. Although the latter is not a worker's immission rating level, it can, however, assist in identifying any potential problems that could cause annoyance, activity interference, or hearing damage to operators and bystanders. Annex A describes test accessories (test table, typing robot). Annex B contains - in addition to the framework standards - specifications for other measurement surfaces. Regarding the installation and operating conditions for specific equipment categories, Annex C refers to the corresponding specifications in ECMA-74. Detailed methods for determination whether the noise emission includes prominent discrete tones or is impulsive in character are specified in Annexes D and E. This standard is suitable for type tests and provides methods for manufacturers and testing laboratories to obtain comparable results. The most significant changes with respect to the 2002 edition of the standard are as follows: - adaptations in the main part to the changed framework standards of the DIN EN ISO 3741 series and the following and DIN EN ISO 11201 and the following, such as definitions, instrumentation and their calibration, calculation of band sound power levels, calculation of A-weighted sound power levels in reverberation rooms and under free field conditions over a reflecting plane, calculation of the band emission sound pressure levels and calculation of A-weighted sound power levels, information to be recorded and reported; - expansion of the permissible measurement surfaces (Annex B) by cylindrical measurement surfaces; - replacement of the installation and operating conditions for specific equipment categories (Annex C) by referring to ECMA-74; - fundamental revision of Annex D on the identification and evaluation of prominent discrete tones in accordance with the tone-to-noise ratio method and the prominence ratio method; - complete editorial revision. The International Standard on which this standard is based has been prepared by Working Group 23 "Measurement of noise from information technology, business and telecommunications equipment" of ISO/TC 43/SC 1 "Noise". The responsible national Mirror Committee is 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, with the collaboration of the Information Technology and selected IT Applications Standards Committee (NIA).