You need to calibrate the equipment in laboratories:
- Once every 12 months.
Or
- According to manufacturers’ recommendations.
- Whichever is shorter.
You also need to carry out field calibration of the equipment before and after noise monitoring.
If both readings differ by more than 0.5 dB, you must not use the readings and redo.
More information can be found in the WSH Guidelines on Hearing Conservation Programme.