Comparison of calibration facilities

Project Description

A national calibration service for hygrometers is under development in Estonia. As a part of the EU project EuropeAid/113156/D/SV/EE, a new facility based on a climatic chamber and chilled mirror hygrometer was purchased and put into operation at the University of Tartu. MIKES provided training and consultation.

To complete the initial validation of the facility, measurement procedures and skills of the personnel, a comparison is arranged between MIKES and University of Tartu. Four capacitive relative humidity hygrometers are used as the transfer standards. They are calibrated at both laboratories at the following points:

Two set of measurements will be carried out at MIKES for monitoring the stability of the hygrometers.

Final Report 2004-11-11

A national calibration service for hygrometers is under development in Estonia. As a part of the EU project EuropeAid/113156/D/SV/EE, a new facility based on a climatic chamber and chilled mirror hygrometer was purchased and put into operation at the University of Tartu. MIKES provided training and consultation. To complete the initial validation of the facility, measurement procedures and skills of the personnel, a comparison was arranged between MIKES and University of Tartu. Four capacitive relative humidity hygrometers were used as the transfer standards. At first, they were calibrated at MIKES and then at University of Tartu. Finally, MIKES carried out measurements for monitoring the stability of the hygrometers. All the measurements at MIKES were carried out using a climatic chamber and a chilled mirror hygrometer.

The difference between the calibration results obtained by the laboratories was calculated. The standard uncertainty due to the long-term instability of the hygrometers (0.2 %rh to 0.6 %rh) was included in the expanded uncertainty of the difference. Also, the normalized error was calculated. Estimates and expanded uncertainties for the difference are shown in table below.