Dr. Martin Thedens is the Chair of IEC TC 31 "Equipment for explosive atmospheres" and will be speaking at Hazardex Live! 2023 about the committee's work in preparing and maintaining standards relating to equipment in explosive atmospheres.

The IEC TC 31 “Equipment for explosive atmospheres” is the international standardization committee to prepare and maintain standards relating to equipment for use where there is a hazard due to the possible presence of explosive atmospheres of gases, vapours, mists or combustible dusts.

It includes three subcommittees: SC 31G “Intrinsically-safe apparatus”, SC 31J “Classification of hazardous areas and installation requirements” and SC 31M “Non-electrical equipment and protective systems for explosive atmospheres”. IEC TC 31 is responsible for more than 50 IEC, ISO and ISO/IEC standards.

Standards must be updated regularly. The latest edition of a published standard describes the state of the art at the time of the publication. A new edition of a standard supersedes the former edition as the state of the art has changed. This does not mean that the level of safety has changed, but requirements to be fulfilled can be new, modified or extended. Within each standard, a list of changes and a classification of changes including justifications are given as part of a table in the Foreword. The foreword of an IEC standard is available free of charge.

IECEx is the IEC system for certification to standards relating to equipment for use in explosive atmospheres. It uses quality assessment specifications that are based on international standards, mainly prepared by the IEC TC 31. IECEx has four different schemes for certified equipment, certified service facilities, certification of personnel competencies, and conformity mark licensing. The procedures for the certification itself and for the complete IECEx System are given in specific IECEx rules, Operational Documents (OD) and Decision Sheets (DS) issued by the IECEx Management Committee (MC) and by the IECEx Testing and Assessment Group (ExTAG). The members of IECEx are bodies which have been accepted according to the IECEx Rules, and which are notified to the ExMC by the National Committee of the IEC.

In the European Union, the IEC TC 31 standards are used as EN versions based on parallel voting procedures. Most EN standards are technically identical to the IEC standards. The national standards are “only” translations of the EN IEC versions. In other countries around the world, the IEC TC 31 standards are used as a basis for national standard versions with or without modifications or additional requirements.

Dr. Martin Thedens

Dr. Martin Thedens is the Head of PTB-Department 3.6 "Explosion Protection in Sensor Technology and Instrumentation", Head of Sector 1 "Explosion Protection and Shooting Devices" of PTB’s Conformity Assessment Body, Chair of IEC TC 31 "Equipment for explosive atmospheres", Chair of DKE K241 "Explosion Protected Electrical Equipment" (DE mirror to IEC TC 31), and the Immediate Past Chair of ExNBG (official group of the European Commission for the ATEX Notified Bodies).