The main standards for explosive atmospheres

IECEx System (https://www.iecex.com/) – from the International Electrotechnical Commission, is a voluntary certification system that verifies compliance with IEC standards related to safety in explosive atmospheres. The IECEx System covers four main areas:

• Certification of service facilities
• IECEx equipment certification
• Ex marking conformity
• Certification of Personnel Competencies

In order for equipment to receive a conformity “Ex” marking under the IECEx System, it must obtain a certificate of conformity. To obtain a certificate of conformity, there must be:

• An accepted IECEx Quality Assessment Report (QAR)
• An accepted IECEx Test Report for type testing (ExTR)

Products with the IECEx conformity mark have received the IECEx Certificate of Conformity, which confirms the product has the appropriate protection for use in explosive atmospheres and that it has been manufactured under a system subject to ongoing surveillance by Certification Bodies. The marking also indicates that the product can be supplied to the market without the need for additional testing. The exception is increased safety (EX e) motor protection type, which must always be tested with the drive it is used with.

Commonly referred to as ATEX, from the French “ATmosphères EXplosibles”, the European Directives is a combination of two EU directives: the Worker Protection Directive 1999/92/EC and the Product Directive 2014/34/ EU. This provides guidelines similar to the IECEx System, with a few exceptions, and without the certification of service facilities and certification of personnel competencies. Compliance with the “Essential Health and Safety Requirements” described in the directives is mandatory within the European Union countries. The easiest way to show compliance is to follow harmonized standards.

The Worker Protection Directive 1999/92/EC defines the minimum health and safety requirements for workers operating in potentially explosive atmospheres.

The Product Directive 2014/34/EU defines product or equipment safety and protective system function safety when used in potentially explosive atmospheres. This directive replaces ATEX 95 and the previous Product Directive 94/9/EC.

In addition to IECEx and ATEX there are several local standards that may be in effect in certain countries.

• IEC/EN 60079-0 Equipment - General requirements
• IEC/EN 60079-1 Equipment protection by flameproof enclosures “d”
• IEC/EN 60079-7 Equipment protection by increased safety “e”
• IEC/EN 60079-15 Equipment protection by type of protection “n”
• IEC/EN 60079-31 Equipment dust ignition protection by enclosure “t”
• IEC/EN 60079-14 Electrical installations design, selection and erection
• IEC/EN 60079-17 Electrical installations inspections and maintenance
• IEC/EN 60079-19 Equipment repair, overhaul and reclamation
• IEC 60050-426 Equipment for explosive atmospheres
• IEC/EN 60079-10 Classification of hazardous areas (gas areas)
• IEC 60079-10-1 Classification of areas - Explosive gas atmospheres
• IEC 60079-10-2 Classification of areas - Combustible dust atmospheres

Many countries have regulations concerning both the design and use of electrical devices in potentially explosive atmospheres, and these may differ. These regulations have become increasingly harmonized within the framework of IEC recommendations and European Standards. National requirements might still need to be met for final approval of installation eg, in Russia, Brazil, Australia or Japan, but they generally relate to one of the main standards below. 

• IEC: International Electrotechnical Commission
• EN: European Norm
• NEC/CEC: National Electrical Code / Canadian Electric Code (500 or 505) in North America