Infrared radiation thermometers are used in a wide range of processes in the steel, non-ferrous metals, glass, ceramics and aero-engine industries among many others. Standards for radiance temperature measurement in the infrared have been developed in several European countries, but until now they have never been intercompared. Moreover, there was evidence of significant discrepancies in the past.
This project aimed to establish the level of equivalence of calibrations of infrared radiation thermometers within Europe in the temperature range 800°C to 2000°C.
The results showed that the calibrations carried out in the participating laboratories were consistent within the target uncertainty of 0.2% of temperature. In most cases the calibrations were within 0.1%. The intercomparison has thereby:
ensured uniformity at European level in the calibrations of national metrology laboratories;
ensured that measurements are executed correctly;
highlighted some important causes of error, such as that due to the size of the source;
facilitated the establishment of mutual recognition agreements;
formulated basic guidelines for the use of transfer standard IR thermometers.
A transfer standard infrared radiation thermometer was circulated between the participating laboratories. The calibrations obtained were compared with the reference calibration performed by the co-ordinating laboratory. In total, seven national metrology institutes in the EU participated: NPL (GB) - co-ordinator, PTB (DE), INM (FR), IMGC (IT), NMi (NL), SP (SE) and CMA (FI).