An investigation of the base metal thermocouples uncertainty components in ILC comparison

This paper is about unique the interlaboratory large comparison organized under EA-2/14 - Procedure for Regional Calibration ILCs in Support of EA MLA and describe final results of the comparison and several pitfalls when measuring temperature with base metal thermocouple. Interlaboratory comparison (ILC) serves as a tool for comparison of measurement results carried out by accredited or non-accredited calibration laboratories in the relevant field of measurement. ILC represents very effective means to demonstrate technical competence of the participant and also serves as a technical base for accreditation. The subject of this comparison was calibration of several pieces the N-type thermocouples. The pilot laboratory of this ILC was the Department of primary metrology of thermo-technical quantities of the Czech Metrology Institute. The reference values of the test items were provided by the above mentioned organizational unit this company. The evaluation of the measurement results of participating laboratories was performed on the basis of E _n score (EN ISO/IEC 17043). In this ILC program 47 accredited calibration laboratories from different European countries and also from Bosnia and Hercegovina, Switzerland and Turkey have participated. The results of this comparison demonstrate satisfactory agreement of the majority of the participants measured values with the reference ones within their stated expanded uncertainties. The article also highlights the basic and often neglected components of uncertainty.