The instruments used for occupational noise measurements are called noise dosimeters, also referred as “personal sound exposure meters”. The noise dosimeter is a wearable sound level meter of a class 2 accuracy. The personal noise dosimeter may be worn on the shoulder, collar, or other location close to the ear.
The ISO 9612 recognizes the use of hand-held sound level meters as well as personal noise dosimeters. The preferred instrument is noise dosimeter, meeting requirements of IEC 61652 and IEC 61672-1, class 2. In case of measurements in low temperatures or when noise is dominated by high frequencies the class 1 instruments are recommended.
Measurement instrumentation should be calibrated before and after each series of measurement and additionally should be verified in the accredited laboratory at leas once every 2 years.