scope:

This standard describes instruments (sound level meters) for the measurement of certain frequency and time weighted sound pressure levels. This standard specifies sound level meters of four degrees of precision, designated Types 0, 1, 2 and 3. The specifications for Types 0, 1, 2 and 3 sound level meters have the same centre values and differ only in the tolerances allowed. Tolerances generally broaden as the type number increases and differ for the various types to a degree which affects manufacturing costs significantly.