Comparison of blackbodies for calibration of infrared ear thermometers

The article will present the results of the EURAMET project no. 927 "Comparison of blackbodies for calibration of infrared ear thermometers (IRETs)". For the comparison MIRS/UL-FE LMK was chosen as the pilot laboratory. The objective of the comparison was to determine the agreement of blackbodies used for the calibration of IRETs among European national laboratories. To verify the accuracy of an IRET a suitable blackbody is needed. An essential requirement is related to accuracy. There are several standards in the world, which describe requirements for IRETs and a blackbody. In the EU this is the standard EN 12470-5, which is a harmonised standard and supports the Medical Device Directive (MDD). Other standards are ASTM standard, Designation E 1965 – 98 and the draft of Japan Industrial Standard JIS T 4207, 2005: Japanese Industrial Standard: “infrared ear thermometers.”. The International Organization for Standardization (ISO) is developing a new standard for clinical thermometers, which will include also IRETs. The basic requirement for accuracy in EN 12470-5 is that the maximum permissible error of IRET is ±0,2 °C in the range from 35,5 °C to 42,0 °C, while the uncertainty of a blackbody is required to be at the most ±0,07 °C. An example of a blackbody is presented in Annex C of the standard EN 12470-5. Such a blackbody related to this standard, designed for the calibration of ear thermometers and immersed in a stirred water bath, was provided for the comparison by the pilot laboratory. The difference to the standard was horizontal positioning of the blackbody, while in the standard a vertical position is suggested.