Changes in Ecma standards for measurement of noise from IT products

This paper discusses changes in new editions of Ecma standards for noise from information technology (IT) equipment and future work items. The tenth edition of ECMA-74 (measurement of IT equipment noise) and the fourth edition of ECMA-108 (measurement of high frequency noise) were approved in December 2008. The major changes were: new product categories (multi-function devices and hand-held devices); operating modes for central processing units; and the concept of threshold of hearing when evaluating very low noise products for prominent discrete tones. The new editions reflect changes being made in the basic sound power level and emission sound pressure level standards: ISO 3741, ISO 3744, ISO 3745 and ISO 11201. Future work items for these standards include revision of ECMA-108 to cover the testing of products whose emissions vary with temperature, revision to ECMA-109 on determining declared noise emission values, and revisions in ECMA-74 Annex C to modify printing patterns and add further new product categories. ISO/FDIS 7779 (measurement of IT noise) references Annex C of ECMA-74 for product categories and product operation ensuring that ISO 7779 test methods include the latest products and customer usage. Future work includes development of an Ecma technical report on reporting fan performance using constant sound power (“iso-acoustic”) curves and testing fans to determine system inlet effects.