Calibration of Noise Dosimeters
Calibration of personal sound exposure meters in accordance with PN-EN 61252
Calibration of personal sound exposure meters in accordance with PN-EN 61252
Personal sound exposure meters, commonly known as noise dosimeters, require calibration—like other measuring equipment—to ensure metrological traceability for accredited measurements. Acoustic dosimeters are most frequently used in workplaces where employees are exposed to excessive noise levels. The calibration certificate guarantees the accuracy of the measurements performed by the dosimeter. As the name implies, these are personal devices, typically worn near the employee’s ear.
The SVANTEK calibration laboratory performs the calibration of personal sound exposure meters in accordance with PN-EN 61252, “Electroacoustics – Specifications for personal sound exposure meters.” All measurements are executed in full compliance with the requirements of this standard. Calibration must be performed under controlled environmental conditions: temperature between 20°C and 26°C, relative humidity from 25% to 70%, and static pressure from 970 hPa to 1050 hPa. These conditions are monitored both before and after the measurement series.
During the calibration of a dosimeter, tasks such as determining the acoustic sensitivity, frequency weighting characteristics, linearity of the dosimeter, and its response to short-duration signals and impulses are performed. Additionally, the overload indicator and the linearity errors of the dosimeter’s response to changes in integration time are checked. All of these determined parameters completely characterize the dosimeter’s operation.
The calibration certificate for a personal sound exposure meter includes client information, the date of issue, the date the measurements were performed, the environmental conditions during the measurements, and a complete series of measurement results with their associated uncertainties, presented in tabular form.
Upon arrival at the laboratory, the equipment can only be calibrated after it has reached environmental equilibrium. This stabilization period usually takes about 4 to 5 hours. The calibration of personal sound exposure meters is quite time-consuming; for instance, determining linearity errors can require a single measurement taking up to 720 s. For determining the response to short-duration signals, the integration time for just one measurement can be nearly 50 minutes. Consequently, the calibration of dosimeters, similar to sound level meters, can take 2 to 3 working days.
The cost of calibrating a personal sound exposure meter depends on the number of dosimeter channels. Octave or third-octave band filters can also be calibrated within the dosimeters.
