ATEX (ATmosphere EXplosibles) is a set of two European Union directives that were created to protect workers from explosion hazards in industries – wherever flammable materials are handled and potentially explosive atmospheres can arise.

The two directives are as follows:

Directive 1999/92/EC on the minimum requirements for improving the safety and health protection of workers exposed to potentially explosive atmospheres (also known as the “ATEX Workplace Directive”)

This directive aims to establish and harmonize minimum requirements to improve the safety and health protection of workers exposed to explosive atmospheres.

It covers employers’ obligations to identify and manage risks associated with potentially explosive atmospheres to protect their workers, such as:

  • Performing explosion risk assessments
  • Performing classification of dangerous areas
  • Implementation of preventive and protective measures against explosions
  • Coordination of all measures aimed at the health and safety of workers and their inclusion in the explosion protection document
  • Creating and updating the explosion protection document

Directive 2014/34/EU on the harmonization of the laws of the Member States relating to equipment and protective systems intended for use in potentially explosive atmospheres (also known as the “ATEX Directive for products”). This directive applies to electrical and non-electrical equipment and protective equipment and systems intended for use in potentially explosive atmospheres.

As of April 20, 2016, it replaces the previous ATEX directive 94/9/EC, which was valid from July 1, 2003 to April 19, 2016.

Equipment and protective systems intended for use in areas where potentially explosive atmospheres may exist must be designed from an integrated explosion safety point of view. Therefore, the equipment manufacturer must ensure the following details:

  • Preventing the creation of explosive atmospheres or causing explosions from equipment and protective systems
  • Preventing the equipment and protective system from becoming an effective source of explosion initiation
  • If an explosion should nevertheless occur, the equipment and protective system should be designed and used in such way as to be able to stop it immediately or limit the consequences of the explosion pressures to a sufficient level of safety

What are explosive atmospheres?

According to the ATEX Directive for workplaces, “explosive atmosphere” means a mixture present with air under atmospheric conditions of combustible substances in the form of gases, vapors, mists or dusts, in which after ignition, combustion spreads to the entire unburned mixture.

Where can explosive atmospheres occur?

All equipment handling flammable substances is exposed to the risks of explosive atmospheres. This includes facilities in industries such as biotechnology, chemical, food and beverage, logistics and supply chain, mining extraction, oil and energy, pharmaceutical, renewable energy, wine and alcohol, etc.

What is the sufficient level of safety for equipment intended for use in potentially explosive atmospheres according to the ATEX Directive for products?

The level of safety of the equipment depends on the probability of the formation of a flammable atmosphere. By the higher probability of the presence of a flammable atmosphere, are thereby higher the requirements for the equipment when operating in such a place. In case an explosion should occur that could directly or indirectly endanger persons and possibly also domestic animals or property, it is necessary to stop it immediately and / or limit the extent of the flame explosion and the explosion pressures to a sufficient level of safety.

In addition, protective systems must be dimensioned in such way as to minimize the effects of an explosion to a sufficient level of safety.

Which areas are covered by the ATEX directives?

The ATEX directives are mandatory for equipment handling flammable substances located in the European Union and the countries of the European Economic Area, i.e. Liechtenstein, Iceland and Norway, and for equipment manufacturers, who would like to introduce their products to this market.

What are ATEX zones and hazardous area classifications?

According to the ATEX Workplace Directive, workplaces must classify their industrial equipment and process areas where potentially explosive atmospheres may exist into “dangerous zones” based on the frequency and duration of occurrence of an explosive atmosphere. The directives trace between the two main types of explosive atmospheres:

  • Gases
    • Zone 0 – Very high level of danger of explosive atmospheres that occur regularly or for a long time during normal operation.
    • Zone 1 – High level of danger where an explosive environment may occasionally occur during normal operation.
    • Zone 2 – Normal level of danger, where the occurrence of an explosive environment is low, and if it occurs, this condition will take only for a short time.
  • Dusts
    • Zone 20 – Very high level of danger of explosive atmospheres that occur regularly or for a long time during normal operation.
    • Zone 21 – High level of danger where an explosive environment may occasionally occur during normal operation.
    • Zone 22 – Normal level of danger, where the occurrence of an explosive environment is low, and if it occurs, this condition will take only for a short time.

What are the groups and categories of ATEX equipment and to which ATEX zones are they applied?

The ATEX directives divide ATEX equipment into groups and categories to meet each ATEX zone.

How is equipment with an ATEX certificate marked?

The ATEX directive for products or equipment requires that the relevant product or equipment and protection systems are marked with a CE mark, an “Ex” mark and series of a codes. These codes are explained in the following pattern.