Applies to instruments which detect sound intensity by pairs of spatially separated pressure sensing microphones and specifies performance requirements for instruments used for the measurement of sound intensity, and their associated calibrators. The purpose of this standard is to ensure the accuracy of measurements of sound intensity applied to the determination of sound power in accordance with ISO 9614. To meet the requirements of that standard, instruments are required to analyse the sound intensity in one-third octave or octave bands, and optionally to provide A-weighted band levels.