Results of the first electrostatic proficiency testing program IEC 60079-0 versus IEC 60079-32-2 and necessary consequences

Abstract

Laboratories in the field of explosion protection (Ex-testing laboratories) are required to participate in proficiency testing programs in order to fulfill the requirement of performing interlaboratory comparisons. This paper introduces the electrostatic proficiency testing program titled "Electrostatic Charge – Test Round 2015″ as part of the “PTB Ex Proficiency Testing Scheme”, which represents the first comprehensive proficiency testing scheme in explosion protection. More than 50 laboratories all over the world performed surface resistance measurements and transferred charge tests in accordance with IEC 60079-0 (2011) and IEC 60079-32-2 (2015) on various types of test samples.Although both standards use what is essentially the same test setup, there exist several differences between the test procedures, which may lead to different results. The analysis of the participants' results shows that factors such as the type of electrodes, the level of the measuring voltage, the precleaning procedure, the relative humidity and the definition of the threshold limits can have an influence on the outcome of the tests. In this work, the differences between both standards – IEC 60079-0 (2011) and IEC 60079-32-2 (2015) – and the issues associated with using two different procedures to reach the same goal are discussed and illustrated.