This Standard ECMA-108 specifies four methods for the determination of the sound power levels of highfrequency noise emitted by information technology and telecommunications equipment in the frequency range covered by the octave band centred at 16 kHz@ which includes frequencies between 11@2 kHz and 22@4 kHz. They are complementary to the methods described in Standard ECMA-74. The first three methods are based on the reverberation test room technique. The fourth method makes use of a free field over a reflecting plane. The test conditions which prescribe the installation and operation of the equipment are those specified in ECMA-74. While the four methods described in this Standard are particularly suitable for information technology and telecommunications equipment@ they may also be applied to other types of equipment. NOTE The sound power level in the 16 kHz octave band determined in accordance with this Standard typically is subject to a standard deviation of approximately 3 dB.