Specifies requirements and describes procedures for the measurements of sound pressure levels in air at a single point in space. These requirements and procedures apply primarily to measurements performed indoors but may be utilized in outdoor measurements under certain specified conditions. This is a fundamental standard applicable to a wide range of measurements and to sounds which may differ widely in temporal and spectral characteristics; a classification is given to the types of sound generally encountered, and the preferred descriptor for each type is identified. This standard is intended to be used by practitioners in the field, as well as by members of the general public who have little or no special technical training in areas relating to acoustics.