Explosion-proof equipment has come a long way since the days when miners carried canaries down into coal mines. IEC Standards and Conformity Assessment System IECEx brought significant improvements to the lives of these workers of the extreme.

Coal miners have come a long way since relying on canaries for their safety.

Coal miners have come a long way since relying on canaries for their safety.

In the English language, a canary in a coalmine describes a person who senses dangers ahead of anybody else. The idiom comes from the way miners would use the birds to detect dangerous gas emissions underground: dying canaries sent a signal for the workers to leave the mine immediately. This very basic alarm system would be much improved over time.

Trip down memory lane

The first attempts to design explosion-proof equipment were made in the 19th century. Fuel-based oil lamps, used to bring light into the mines, were fitted with a cylindrical glass enclosure to protect the flame. This was very rudimentary, and, in those days, a great number of mining accidents occurred. The material damages and human fatalities pushed for the development of safer equipment.

Electricity came to the mines in the first decades of the 20th century and certainly made life somewhat easier for the miners who could then rely on electric motors, better lighting of tunnels and communication with the outside of the mine. A German mining engineer, Carl Beyling, devised several protection techniques, the ancestors of today’s Ex flameproof protection. Flameproof protection means that the parts that can ignite in an explosive atmosphere are within an enclosure that can withstand the force and pressure created and developed during an internal explosion, thus greatly minimizing the risks of igniting an external explosion.

During the first decade of the 20th century came the realization that not only gases but also coal dust could lead to mine explosions. A series of accidents in the US and in Europe led the authorities to investigate and take the first measures to improve the security of their mine workers. But dust – and the risk of explosion – is present in many other sectors. Flour, sawdust and sugar can be as explosive as coal dust. Vapours, mists and gases are other factors that may trigger explosions when in the presence of spark ignition.

The growing need for standards

The first half of the 20th century saw the publication of the first standards for equipment in explosive atmospheres, mainly in the UK and Germany and throughout the second half of the 20th century, authorities and industries honed their knowledge and expertise, developing more stringent measures to increase the safety of workers and installations in hazardous environments.

The growing use of electrical equipment by mines and factories made it even more critical to devise appropriate measures, and to standardize all equipment destined for the explosive (Ex) sector. The IEC, sharing the concerns expressed by authorities and industry, set up Technical Committee (TC) 31: Equipment for explosive atmospheres, to “address the need to develop techniques for ensuring electrical equipment would not provide an explosion risk when used in hazardous areas involving gases, vapours, dusts and mists.” For the past 70 years, it has prepared international standards – the IEC 60079 series – that provide the Ex industry with the strictest requirements covering the whole life cycle of Ex equipment, from design and manufacture to installations, maintenance and repair. They also deal with the competence of personnel working in Ex areas. 

More recently, with ISO 80079-36 and ISO 80079-37, TC 31 has added non-electrical equipment, i.e. “equipment which can achieve its intended function mechanically” to its library of standards. 

More than 25 years of IECEx certification

The first meeting of IECEx, the IEC System for Certification to Standards Relating to Equipment for Use in Explosive Atmospheres, took place in London, UK, in July 1996. With the establishment of a conformity assessment system dedicated to explosive atmospheres, the IEC reinforced its presence and growing influence in the sector. From then on, industry, regulators and governments had the tools to ensure that equipment used in hazardous areas did indeed meet the strict requirements enunciated in IEC 60079. 

In its more than 25 years of existence, IECEx has extended its offer, leading to the creation of two schemes to complement the original IECEx Certified Equipment Scheme. First the IECEx Certified Service Facilities Scheme, then the IECEx Scheme for Certification of Personnel Competence. And in 2016, following the publication of ISO 80079-36 and ISO 80079-37, it began the testing and certification of non-electrical equipment as well. 

IECEx has been endorsed by the United Nations (UN) through the UN Economic Commission for Europe (UNECE) as THE certification system for the assessment of conformity in Ex areas.

Looking ahead towards hydrogen

Not resting on its achievements, IECEx is now focused on the future. In 2021, it formed a new expert working group dedicated to the application of IECEx to standards related to the production, distribution and dispensing of hydrogen. It established close ties with ISO/TC 197: Hydrogen technologies, and this collaboration is expected to result in IECEx issuing certificates covering hydrogen dispensing equipment and systems by the end of 2022.

Increased safety

Standards, testing and certification, technological advances and increased security measures have definitely helped in the prevention of and decrease in industrial accidents. The more manufacturers and buyers of Ex equipment rely on standards and certification, and the more regulators and legislators use them as a basis for their legislation, the better employees will be protected from the hazards of their working environment.