The ATEX directives are a pair of directives from the European Committee for Standardization created to protect people from ATmosphères EXplosibles—explosive atmospheres—in the European Union. The directives address the minimum safety requirements for workplaces and equipment used in explosive atmospheres.
ATEX protects employees from explosion risks with a "workplace" directive and an "equipment" directive. Used in industries where workers often operate in harsh conditions, like oil, gas, and mining, it requires that potentially explosive areas be classified into zones based on the chance of that area having an explosive atmosphere.
Any area in which a mix of substances like gasses, vapors, dust, or fibers combine with air, under atmospheric conditions, may combust if exposed to a spark.
Attempting to establish an international certification system to address risk prevention, the International Electrotechnical Commission System (IECEx) provides a similar model to ATEX. While there is no exact, one-to-one equivalent to ATEX in North America, multiple similar but unique systems to classify hazardous areas are used and overseen by a handful of industry organizations.
Why Is General Awareness of ATEX Important?
It's helpful for people, in general, to be aware of safety hazards and how those hazards might arise in an industrial area.
And it remains useful for industrial professionals to be aware and reminded of ATEX and its importance. Even with layers of safety procedures, people can become complacent, and terrible things still sometimes happen.
Therefore, it's good to revisit the basics of working in hazardous environments to ensure people stay safe and keep the potential for dangerous events top of mind. The need for preparedness will always apply as long as avoidable explosions are part of the industrial experience.
The ATEX Zone and Category System
ATEX separates hazardous locations into zones for gasses/vapour and dust.
The zones are divided based on the frequency and duration of an explosive atmosphere in a given place. Equipment for use in those environments is separated into categories that define the settings in which people can safely operate them.
ATEX zones for gases/vapour:
- Zone 0 (gases/vapours). A place in which an explosive atmosphere consisting of a mixture with air of dangerous substances in the form of gas, vapour, or mist is present continuously or for long periods or frequently.
- Zone 1 (gases/vapours). A place in which an explosive atmosphere consisting of a mixture with air of dangerous substances in the form of gas, vapour, or mist is likely to occur in normal operation occasionally.
- Zone 2 (gases/vapours). A place in which an explosive atmosphere consisting of a mixture with air of dangerous substances in the form of gas, vapour, or mist is not likely to occur in normal operation but, if it does occur, will persist for a short period only.
ATEX zones for dust:
- Zone 20 (dusts). A place in which an explosive atmosphere in the form of a cloud of combustible dust in the air is present continuously, or for long periods or frequently.
- Zone 21 (dusts). A place in which an explosive atmosphere in the form of a cloud of combustible dust in the air is likely to occur in normal operation occasionally.
- Zone 22 (dusts). A place in which an explosive atmosphere in the form of a cloud of combustible dust in the air is not likely to occur in normal operation but, if it does occur, will persist for a short period only.
ATEX categories for equipment:
- Category 1: Zone 0 and 20
- Category 2 or 1: Zone 1 and 21
- Category 3 or 2 or 1: Zone 2 and 22
Any equipment approved for use in a higher risk zone can be used in any lower risk zone, including outside hazardous environments entirely. Equipment approved for use in hazardous zones includes a seal indicating that it meets ATEX standards.
How Does ATEX Help Human Beings Stay Safe?
ATEX and similar directives across the world help keep human beings safe from explosive industrial accidents by providing guidelines designed to avoid accidents.
Ensuring that electrical and non-electrical equipment used in hazardous locations is "intrinsically safe" is the primary management technique used to prevent explosions. To be intrinsically safe, the device's design intentionally prevents any chance that it could spark an explosion under any circumstance.
Intrinsically or inherently safe devices include various tools for equipment inspection, such as mobile tablet devices and personal safety alert devices for use in specifically rated hazardous environments.
The kinds of industries with potentially explosive environments often contain other areas that are not the safest places for human beings. Traditionally, people are still needed to enter those areas from time to time, most frequently to inspect their equipment in order to assure the continued collective safety of other workers, the community, and the larger environment.
Additional Options for Human Safety
Fortunately, many new technologies continue to be developed to protect people from workplace environments that demand extra caution, even if they're not considered an explosive atmosphere under the ATEX directives.
Remote visual inspection (RVI) conducted by drones and robots plays a role in keeping people safe by using devices that enter hostile environments, thereby preventing people from needless exposure to dangerous situations. And while technically few robotic inspection tools (including aerial drones) will ever meet the ATEX intrinsic safety requirements, they are still valuable assets for industries in which explosive environments are frequently found.
One standard method used by leading industries for working with robots in explosive environments is environmental mitigation.
Environmental mitigation renders the explosive environment inert, allowing safe entry into the space. For example, a hazardous atmosphere is pressurized with a non-explosive gas, like nitrogen, until there is no danger of explosion.
While non-explosive, these areas are still dangerous and require the use of extensive personal protective equipment, including oxygen, for a person to enter the environment. Confined spaces present additional personal safety risks, making avoidance of those places through the use of robotics appealing for everyone involved.
Instead of human entry, robots like drones, crawlers, and submersibles can collect data in those environments, either autonomously or directed by human controllers who are kept far away from any hazards.
Direct human intervention can be reserved for the occasions when an inspection reveals an issue. At that point, the space can be made ready for human entry for repair or for a more detailed inspection.
Due to improved safety outcomes for workers and cost and time savings, this method has many advantages and is becoming more widely embraced.
Updates to the ATEX Directives
The rules about ATEX are revisited regularly by the European Commission to define minimum requirements to improve employees' health protection and safety.
The last supplement was added in 2014 and included clarifications and terminology changes. Other changes included the classification of areas in zones where a potentially explosive atmosphere may occur and required the use of a warning symbol to indicate such areas.