Learn about ATEX, the European Union's safety standard for protecting workers in explosive atmospheres.
Published 22 May 2023
ATEX stands for “ATmospheres EXplosives”. The European Union directive consists of safety procedures regarding material, equipment, and systems used in environments with a risk of potentially explosive atmospheres.
The standards apply to any activity with the potential for contact with flammable materials or marked by crystalline silica and oxygen-enriched atmospheres. ATEX-certified products have been tested to meet certain requirements, ensuring they are safe and effective in explosive environments.
The ATEX directive regulates the products used in such locations and the best practices for working safely in them. It includes providing suitable personal protective equipment such as chemical-resistant clothing, respirators, and face shields.
Under the Dangerous Substances and Explosive Atmospheres Regulations (DSEAR), an explosive atmosphere is described as a mixture of dangerous substances in the form of gases, vapors, mist, or dust with air in atmospheric conditions that ignites and spreads combustion to the unburned entire mixture.
In atmospheric conditions, the temperature and pressure are between –20°C and 40°C and 0.8 to 1.1 bar, respectively.
Two European directives control ATEX, as follows:
This directive sets out the minimum requirements for improving workplace safety in potentially explosive atmospheres. It requires employers to assess the risks in their workplace and take appropriate measures to limit any potential danger arising from flammable substances or dust explosions.
The core purpose of the ATEX Equipment Directive is to ensure that any equipment or protective systems used in hazardous areas follow certain safety requirements according to the legislation outlined in Annex II of this directive. These requirements are intended to reduce the risk of accidental fires or explosions due to faulty design or manufacturing practices.
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IECEx System, or International Electrotechnical Commission System for Certification to Standards Relating to Equipment for Use in Explosive Atmospheres, helps build confidence in the safety of Ex equipment worldwide. In contrast, ATEX is a mandatory application limited to Europe.
IECEx aims to accomplish the following:
In contrast, ATEX certification differs from IECEx certification in several fundamental ways.
Below are some potential applications for ATEX/IECEx-certified equipment:
Employers must classify hazardous explosive atmospheres and equipment into different zones and category types according to the probability of hazard formation and the area where the equipment will operate.
DSEAR Schedules 2, 3, and 4 describe the various classifications.
Equipment is classified into groups and categories based on their markings under the ATEX directive.
It includes equipment intended for use in underground and surface mining areas, likely to be endangered by fire and/or combustible dust.
It includes equipment that may become endangered by explosive atmospheres in other places, such as equipment listed in Annex I of the Directive as Categories 1, 2, and 3.
Potentially explosive areas are classified as Zones (European and IECEx methods) or Classes and Divisions (North American method) according to their likelihood of containing explosive atmospheres.
European & IECEx Classification
Definition of Zone or Division
North American Classification
Zone 0 (gases)
Areas where explosive mixtures are continuously present or present for long periods.
Class I Division 1 (gases)
Zone 20 (dusts)
Class II Division 1 (dusts)
Zone 1 (gases)
Areas which are prone to explosive mixtures under normal conditions.
Zone 21 (dusts)
Zone 2 (gases)
An area in which explosive mixtures will not occur in normal operation and, if they do, only last briefly.
Class I Division 2 (gases)
Zone 22 (dusts)
Class II Division 2 (dusts)
As part of the ATEX directive, the product must be marked with the CE mark, the ‘EX’ mark, and the ATEX certification mark.
according to ATEX directive
Used in underground mines
Intended for use everywhere else
Premises where an explosive atmosphere exists continuously, for a long period, or frequently
Equipment intended to be used in areas likely to have an explosive atmosphere in normal operation requires high protection.
Equipment that must provide a normal level of protection to areas where an explosive atmosphere is unlikely to occur during normal operations.
Flammable gas-certified equipment
Suitable for use in dusty environments
Above-ground surface industries
Gas Sub Group
Less easily ignitable gases, e.g., propane
Combustible gases, e.g., ethylene
Easily ignitable, e.g., hydrogen or acetylene
Apparatus classified as hazardous is classified according to its maximum surface temperature at an ambient temperature of 40°C, or as specified otherwise.
While ATEX is an EU directive, Hazardous Locations (HazLoc) is its US equivalent. Hazardous locations, such as explosive atmospheres, are defined and categorized in the HazLoc standard issued by the Occupational Safety and Health Administration (OSHA).
The Australian standard doesn’t accept ATEX-certified equipment, as it does not comply with the country’s requirements. Since ATEX certification is only required in Europe, IECEx certification is a globally recognized certification to guarantee Ex equipment safety. As a result, equipment used in potentially explosive atmospheres in Australia must be IECEx-certified.
No. The National Fire Protection Association (NFPA) combustible dust standards are not harmonized with ATEX certification, and OSHA doesn’t consider it acceptable for electrical equipment used in hazardous environments. Rather, OSHA requires equipment to be certified by a Nationally Recognized Testing Laboratory (NRTL).
The difference is that ATEX is used in Europe, while Ex-Proof is used in North America and Canada. However, both classifications assist manufacturers in selecting and installing equipment for potentially explosive environments. Additionally, they require determining the process environment and properties of any materials present to classify the ignition risk of any gas and dust atmospheres and take appropriate preventative steps.
SafetyCulture (formerly iAuditor) is an innovative cloud-based safety inspection software that offers users a variety of tools to ensure their equipment, processes, and personnel comply with the ATEX directives. Using SafetyCulture, users can do the following:
Rob Paredes is a content contributor for SafetyCulture. He is a content writer who also does copy for websites, sales pages, and landing pages. Rob worked as a financial advisor, a freelance copywriter, and a Network Engineer for more than a decade before joining SafetyCulture. He got interested in writing because of the influence of his friends; aside from writing, he has an interest in personal finance, dogs, and collecting Allen Iverson cards.
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