Comparison of the realisations of the relative humidity in the range from 10% to 95% at temperatures from -10 °C to 70 °C

Project Description

The purpose of the comparison is to compare the results of the participating laboratories during calibration of a RH sensor in the range from 10 %rh to 95 %rh in the temperature range from -10 °C to 70 °C. The purpose of the comparison is also to support the calibration measurement capabilities (CMC) entries of the participating laboratories.
The comparison is expected to have three loops, co-piloted by LNE-CETIAT and UME.


Final Report 2021-01-05

The project has been completed and the final report can be downloaded here>>.

The evaluation of the results vs KCDB published CMCs can be downloaded here>>.

Results imply mutual consistency of data when the between-laboratory variance is considered. Drift of the impedance-based transfer standards that were circulating for about 3 years cannot be disregarded.
The estimated drift was substantial at air temperature -10 °C. At 10 %rh, the evidence that the uncertainties of the most laboratories are sufficient to account for the observed dispersion of results is masked by a significant between-laboratory variance. Nevertheless, a large number of transfer standards allowed us to gain more confidence in the comparison results by selecting an optimal sensor combination.


Progress Report 2019-06-17

We have experienced additional delay. Alternative estimator of the comparison reference value has been introduced to better account for transfer standards' drift. Draft A report is now produced. The plan is to finalise a Draft B report by the next TC-T meeting in September 2020.


Progress Report 2019-03-23

From the time of the last presentation of the results, the consistency check was performed on the data and the final results with the comparison reference value will be presented and proposed at the EURAMET meeting in Torino on April 11, 2019. After the meeting all the participants will be asked to comment/confirm the Draft B results and the final report. The final results will then be presented at the Tempmeko 2019 in Chengdu.


 Progress Report 2018-03-15

The measurements in all three loops are finished. MIRS/UL-FE/LMK and CETIAT have also performed the final measurements with the instruments in all three loops by February 2016.

Draft A of the results is expected to be presented at the EURAMET meeting on April 26, 2018 in Boras, Sweden.


Progress Report 2017-04-11

The measurements in all three loops are finished. MIRS/UL-FE/LMK and CETIAT have also performed the final measurements with the instruments in all three loops by February 2016.

A first draft of the results is expected to be presented at the EURAMET meeting on April 27, 2017 in Madrid.


Progress Report 2016-02-11

All the measurements in three loops are now finished. MIRS/UL-FE/LMK and CETIAT have performed the final measurements with the instruments in all three loops by February 2016.
The analysis of the results has started.


Progress Report 2015-02-12

All the measurements in the loop 1 are now finished.
In the loop 2, there has been a delay due to staffing and due to inclusion of the new participant (MBW). Measurements are now beeing under way in the MBW (CH), before they go again to MIKES and finally to CETIAT.
Delays have also been reported in the loop 3 due to reference equipment malfunction (resolved), ATA carnet lost at the courier and it's renewal and due to new participants being included - MBM(ME) and JV (NO). The instruments are now at the BoM (MK), before going to HMI/FSB-LPM (HR) and finally back to MIRS/UL-FE/LMK (SI).