The sound pressure level (stated in tenth of Bel =d(ezi)B) is defined as the ratio between the prevailing sound pressure and the sound pressure that man can just perceive at 1,000 Hz (the hearing threshold). The sound pressure level at the workstation is measured by means of standardized filters (A, B, C on D) adjusted to the sensitivity of the human ear; in most cases A filters are used (dB(A)). For assessing the noise exposure at the workstation, the evaluation level must be determined. Also see Permanent Noise Pressure Level.
