Original Article: https://safetyculture.com/topics/atex/
What is ATEX?
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.
What is an Explosive Atmosphere?
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.
What are the Applicable ATEX Directives?
Two European directives control ATEX, as follows:
Directive 99/92/EC (also known as “ATEX 137” or the “ATEX Workplace Directive”)
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.
Directive 2014/34/EU (also known as “ATEX 114” or the “ATEX Equipment Directive”)
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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What is the Difference Between ATEX and IECEx Certifications?
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:
- Reduced certification and testing costs for manufacturers
- Aim to reduce product development time
- Increase product evaluations confidence globally
- Establish a centralized international database
- Make equipment and services more internationally recognizable through IECEx certification
In contrast, ATEX certification differs from IECEx certification in several fundamental ways.
- Jurisdiction – ATEX is an adaptation to match the EU needs that many companies outside the EU still follow.
- Standards – ATEX has its own Essential Health and Safety Requirements (EHSRs) that must be met, although many companies adhere to International Electrotechnical Commission (IEC) standards to demonstrate compliance.
- Certification – ATEX services are provided by organizations called ExNBs. These are specific to the EU and issue EU Type Examination Certifications. The IECEx Management Committee, with a single international process, oversees IECEx certification. IECEx certification bodies and IECEx testing labs are issued certificates of Conformity and recognized globally.
Potential Applications for ATEX/IECEx-Certified Equipment
Below are some potential applications for ATEX/IECEx-certified equipment:
- Production facilities for food, pharmaceuticals, painting, manufacturing, etc., where explosive atmospheres may exist
- Refineries or processing plants for oil, gas, or chemicals
- Explosive atmospheres containing hazardous gases or materials, such as mining sites
- Power plants and other industrial facilities (e.g., refineries, foundries) with potentially hazardous atmospheres
Different ATEX Classifications
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.
Classification of Equipment
Equipment is classified into groups and categories based on their markings under the ATEX directive.
Group I
It includes equipment intended for use in underground and surface mining areas, likely to be endangered by fire and/or combustible dust.
- Category M1 – The equipment in this category must remain functional under explosive conditions and must have integrated explosion protection measures to ensure:
- That when one integrated measure fails, a second measure provides a sufficient level of safety; or,
- That it provides a sufficient level of safety occurs when two faults happen independently.
- Category M2 – The equipment in this category is designed to de-energize in the event of detecting an explosive atmosphere.
Group II
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.
- Category 1 – This category includes equipment certified to remain within the operational parameters stated by the manufacturer and to provide a high level of protection in areas where explosive atmospheres are highly likely to occur and are present continuously, for long periods, or frequently caused by various gas, vapor, mist, or air/dust mixtures.
- Category 2 – This category includes equipment designed by manufacturers to meet operation specifications in hazardous areas likely to include explosive mixtures of air, gases, vapors, mists, and/or dust.
- Category 3 – This category includes equipment designed to operate within the manufacturer’s stated conditions and typically offers adequate protection for its intended use. The areas this equipment operates may intermittently contain explosive gases, vapors, mists, or air/dust mixtures, but typically for a limited time.
Classification of an Area
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. | Class I Division 1 (gases) |
| Zone 21 (dusts) | Class II Division 1 (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) |
Product Marking
As part of the ATEX directive, the product must be marked with the CE mark, the ‘EX’ mark, and the ATEX certification mark.
| Heading | Mark | Use |
| Explosion Protection | according to ATEX directive | |
| Equipment Group | I | Used in underground mines |
| II | Intended for use everywhere else | |
| Equipment Category | 1 | Premises where an explosive atmosphere exists continuously, for a long period, or frequently |
| 2 | Equipment intended to be used in areas likely to have an explosive atmosphere in normal operation requires high protection. | |
| 3 | Equipment that must provide a normal level of protection to areas where an explosive atmosphere is unlikely to occur during normal operations. | |
| Environment | G | Flammable gas-certified equipment |
| D | Suitable for use in dusty environments | |
| Protection Type | d | Flameproof |
| Ia | Intrinsically safe | |
| e | Increased safety | |
| Gas Group | I | Mines |
| II | Above-ground surface industries | |
| Gas Sub Group | A | Less easily ignitable gases, e.g., propane |
| B | Combustible gases, e.g., ethylene | |
| C | Easily ignitable, e.g., hydrogen or acetylene | |
| Temperature ClassificationApparatus classified as hazardous is classified according to its maximum surface temperature at an ambient temperature of 40°C, or as specified otherwise. | T1 | 450ºC |
| T2 | 300ºC | |
| T3 | 200ºC | |
| T4 | 135ºC | |
| T5 | 100ºC | |
| T6 | 85ºC |