Comparison of Air Temperature Calibrations

Project Description

When calibrating thermometers in air thermal resistance between the reference sensor and the sensor under calibration is much larger than in liquid. Therefore, local heat sources or temperature gradients may have a significant effect on the calibration results. Thermal radiation in particular is a potential source of error in air temperature calibrations.

In this project the effects specific to air temperature measurements and calibrations are studied by comparing calibrations performed by the participants with facilities of different types. The comparison is carried out as a single loop using an ASL F250 bridge with two Pt 100 probes and an HMT335 thermohygrometer as the transfer standards. The comparison will cover the range -40 °C to 180 °C. Each laboratory will carry out measurements at five measurement points covering the whole air temperature calibration range of the laboratory.

The time slot for each laboratory is 2 weeks, and the results should be reported within 4 weeks after sending the transfer standards to the next laboratory. A detailed schedule will be agreed separately. Due to a large number of participants only in a very exceptional case results of a laboratory will be included in the final analysis if one (or both) of the dead-lines are exceeded.

A short comparison protocol and a report excel file will be prepared by the coordinator.

Final Report 2013-10-23

The comparison has been completed and the report can be downloaded here >>
Annex 3 can be downloaded here >>