Explosive atmospheres - Part 42: Electrical safety devices for the control of potential ignition sources for Ex Equipment, Type of Protection "f"

This Final Draft International Standard is an up to 6 weeks' pre-release of the official publication. It is available for sale during its voting period: 2026-06-12 to 2026-07-24. By purchasing this FDIS now, you will automatically receive, in addition, the final publication. IEC 60079-42:2026 specifies the requirements for the application, testing and marking of electrical safety devices for the manufacturers of Ex Equipment under control (ExEUC) to reduce the likelihood of potential ignition sources becoming effective in Ex Equipment located in explosive atmospheres with the Type of Protection "f". In the context of this document, safety devices contribute to a safety function to control potential ignition sources from both electrical and non-electrical Ex Equipment in explosive atmospheres. In the context of this document, a safety device could be an element of a safety function, for example, sensor, logic or final element, or a combination of elements performing a complete safety function. A complete safety function can include a manual or an automatic action. This document can also be used for assessing a safety device independently, without it being designed to control specific Ex Equipment or be part of a specific overall safety function. A safety device can be a measure to achieve a required Equipment Protection Level (EPL) of the Ex Equipment with respect to a potential ignition source identified by the ignition hazard assessment. The combination of the safety device and the Ex Equipment could then comply with the relevant standards of the IEC 60079 series and the ISO/IEC 80079 series with respect to the EPL. This document does not apply to: - gas detection to mitigate the presence of an explosive atmosphere; - safety devices to mitigate effects of an explosion; - mechanical safety devices, for example pressure relief valves, mechanical governors and other mechanical devices; or - safety devices to prevent the occurrence of explosive atmospheres, for example inerting systems, pressurization systems and ventilation systems. NOTE Some potential ignition sources might not be practicably controlled by safety devices. For safety devices where the required EPL is identified under other parts of the IEC 60079 series and the ISO/IEC 80079 series of standards this document can be used for the implementation of the required EPL. Safety devices can be installed either as part of or separate to the ExEUC and could be located inside or outside the hazardous area. This document is not applicable where another Type of Protection requires a Specific Condition of Use for a safety device but does not reference this document. This first edition cancels and replaces IEC TS 60079-42 published in 2019. This edition constitutes a technical revision. Refer to the Foreword of the document for a complete listing of the technical changes between edition 8.0 and the previous edition of the document.