This part of IEC 60076 defines sound pressure and sound intensity measurement methods by which sound power levels of transformers, reactors and their associated cooling auxiliaries may be determined. The methods are applicable to transformers and reactors covered by the IEC 60076 series, IEC 60289, IEC 60726 and the IEC 61378 series, without limitation as regards size or voltage and when fitted with their normal cooling auxiliaries.This standard is primarily intended to apply to measurements made at the factory. Conditions on-site may be very different because of the proximity of objects, including other transformers. Nevertheless, the same general rules as are given in this standard may be followed when on-site measurements are made. For the purpose of this standard, the term 'transformer' should be taken to mean 'transformer or reactor'.