The document introduces a series of mine basic international standards describing various methods for determining the sound levels power from all types of machinery and equipment. It provides brief summaries of these basic International Standard ; guidance on the selection of one or more of these standards which are appropriate to any particular type of machinery. The guidance given applies only to airborne sound. It is for use in the preparation of noise test codes for specific machines and also in noise testing where no relevant test code exists. The following terms are defined: emission, sound power, sound power level, sound pressure level, time-averaged sound pressure level, sound energy level, single-event sound pressure level, sound intensity, background noise, background noise level, background noise correction, environmental correction.