| Instrument Type | Grade | Standards |
| Sound Level Meter | Type 0 (Laboratory reference) Type 1 (Laboratory & Field) Type 2 (General Field) Type 3 (Field Check) |
IEC 60651 ANSI S1.4 |
| Integrating Sound Level Meter | Type 0 (Laboratory reference) Type 1 (Laboratory & Field) Type 2 (General Field) Type 3 (Field Check) |
IEC 60804 |
| Acoustic Calibrator | Class 0 (most accurate) Class 1 Class 2 (least accurate) |
BS 7189:1989 IEC 942:1988 IEC 60942:1988 |