This British Standard specifies a procedure for the periodic verification of conformance of a sound level meter or integrating-averaging sound level meter to BS EN 60651 : 1994 or BS EN 60804 : 1994, respectively, including a series of tests and the information to be shown on the calibration certificate. This standard is applicable to sound level meters originally manufactured in accordance with BS EN 60651 : 1994 and BS EN 60804 : 1994. The tests in this standard are therefore based on those in BS EN 60651 : 1994 and BS EN 60804 : 1994 and are intended simply to verify the correct operation of the instrument. This standard is also applicable to sound level meters for the measurement of motor vehicle noise, in so far as an instrument which conforms both to this standard and to 2.1 to 2.4 of BS 3539 : 1986 is deemed also to conform fully to BS 3539 : 1986.