ATEX Directive 2014/34/EU

The ATEX Directive is a key part of legislation governing safety in potentially explosive atmospheres. It is not only a regulatory instrument, but also practical guidance for engineers who must ensure that their designs and products meet the highest safety standards. In this article, we present detailed information on the directive, its requirements, and its practical application across different industries.

What is the ATEX Directive?

The ATEX Directive (Atmosphères Explosibles) is a set of European Union regulations that define the requirements for equipment and protective systems intended for use in potentially explosive atmospheres. The main purpose of the directive is to protect people and property by minimizing the risk of explosions in industrial environments.

This directive is particularly important for industries such as petrochemicals, mining, flour milling, and many others where flammable gases, vapours, or dusts are present. In such environments, a safety audit and appropriate CE certification of machinery are essential to meet the requirements of the Machinery Directive 2006/42/EC and the ATEX Directive.

History and Evolution of the ATEX Directive

The ATEX Directive originated from earlier workplace safety regulations. The first rules appeared in the 1990s, and the current version of the directive, 2014/34/EU, was adopted in 2014. It replaced the earlier Directive 94/9/EC, introducing more detailed requirements for product marking and certification.

ATEX Directive: Conformity Assessment Procedure

Directive 2014/34/EU sets out different conformity assessment procedures for equipment and protective systems intended for use in potentially explosive atmospheres. Below is an overview of when the individual conformity assessment modules and groups apply:

Module Descriptions:

• Module A: Internal production control.
• Module B: EU-type examination.
• Module C1: Conformity to type based on internal production control plus supervised product testing.
• Module D: Conformity to type based on quality assurance of the production process.
• Module E: Conformity to type based on product quality assurance.
• Module F: Conformity to type based on product verification.
• Module G: Conformity based on unit verification.

Explanation of Categories under the ATEX Directive:

• Group I: Equipment intended for use in underground parts of mines and in those parts of surface installations of such mines liable to be endangered by firedamp or combustible dust.
  • Category M1: Equipment providing a very high level of protection. It must remain energized and safe even when an explosive atmosphere is present.
  • Category M2: Equipment providing a high level of protection. It is intended to be de-energized when an explosive atmosphere is present.
• Group II: Equipment intended for use in other places liable to be endangered by explosive atmospheres.
  • Category 1: Equipment intended for use in zones where an explosive atmosphere is present continuously, for long periods, or frequently. It provides a very high level of protection.
  • Category 2: Equipment intended for use in zones where an explosive atmosphere is likely to occur occasionally. It provides a high level of protection.
  • Category 3: Equipment intended for use in zones where an explosive atmosphere is unlikely to occur, and if it does occur, it will persist only for a short period. It provides a normal level of protection.
• Group III: Equipment intended for use in places where the explosive atmosphere consists of combustible dust.
  • Category 3: Equipment intended for use in zones where an explosive atmosphere is unlikely to occur, and if it does occur, it will persist only for a short period. It provides a normal level of protection.

This distinction between categories and conformity assessment modules helps ensure that the appropriate procedures are applied according to the level of risk associated with using a given piece of equipment in a potentially explosive atmosphere.

Module A: Internal production control

1. Technical documentation:
   • The manufacturer prepares technical documentation that makes it possible to assess the product’s conformity with the requirements of the directive. The documentation includes, among other things, a general description of the product, technical drawings, diagrams, descriptions, and the results of tests and risk analysis.
2. Production:
   • The manufacturer ensures that products comply with the technical documentation and the requirements of the directive by applying appropriate control measures during production.
3. CE marking:
   • The manufacturer affixes the CE marking to the product and draws up a written EU declaration of conformity, which must be kept for 10 years from the date the product is placed on the market.

Module B: EU-type examination

1. Application:
   • The manufacturer submits an application for EU-type examination to a notified body, together with the technical documentation.
2. Examination:
   • The notified body reviews the documentation and carries out the appropriate examinations to confirm that the type complies with the requirements of the directive.
3. EU-type examination certificate:
   • Following a positive assessment, the notified body issues an EU-type examination certificate identifying the type’s conformity with the requirements of the directive.

Module C: Conformity to type based on internal production control

1. Production control:
   • The manufacturer ensures that the products manufactured conform to the type described in the EU-type examination certificate by implementing appropriate control measures.
2. CE marking:
   • The CE marking is affixed to the product together with the identification number of the notified body.
3. EU declaration of conformity:
   • The manufacturer draws up the EU declaration of conformity and keeps it for 10 years from the date the product is placed on the market.

Module D: Conformity to type based on quality assurance of the production process

1. Quality system:
   • The manufacturer implements an approved quality system covering production, final product inspection, and testing.
2. Audit:
   • The notified body carries out audits of the quality system and may conduct unannounced visits to the manufacturer to verify that it is operating effectively.

Module E: Conformity to type based on product quality assurance

1. Quality system:
   • The manufacturer submits an application for assessment of the quality system for the products concerned, ensuring conformity with the type described in the EU-type examination certificate.
2. Surveillance:
   • The notified body carries out periodic audits and unannounced visits, verifying product conformity.

Module F: Conformity to type based on product verification

1. Production and verification:
   • The manufacturer ensures that products conform to the approved type and carries out examinations and verification tests.

Module G: Conformity based on unit verification

1. Verification:
   • The notified body carries out the appropriate examinations and tests on each product to confirm its conformity with the requirements of the directive.

These modules form a comprehensive conformity assessment system for products intended for use in potentially explosive atmospheres, ensuring their safety and compliance with European Union requirements.

Equipment Group I and II, equipment categories M1 and 1:

1. Module B (EU-type examination) combined with one of the following:
   • Module D (Conformity to type based on quality assurance of the production process).
   • Module F (Conformity to type based on product verification).

Equipment Group I and II, equipment categories M2 and 2:

1. Module B (EU-type examination) combined with one of the following:
   • Module C1 (Conformity to type based on internal production control plus supervised product testing).
   • Module E (Conformity to type based on product quality assurance).
2. For other equipment in this group and category:
   • Module A (Internal production control) and submission of the technical documentation to a notified body, which acknowledges receipt and retains it.

Equipment Group II, equipment category 3:

1. Module A (Internal production control).

Protective systems:

1. Procedure in accordance with Modules B and D or B and F.

Alternative procedures:

1. Module G (Conformity based on unit verification) may be applied to equipment groups I and II.

Hazardous area zones according to EN IEC 60079

• Zone 0: Areas in which an explosive atmosphere is present continuously or for long periods.
• Zone 1: Areas in which an explosive atmosphere may occur during normal operation.
• Zone 2: Areas in which an explosive atmosphere is not likely to occur during normal operation, and if it does occur, it will exist only for a short time.

Equipment Categories under the ATEX Directive

The ATEX Directive classifies equipment according to the level of protection it must provide in the relevant zones:

• Category 1: Equipment intended for use in places where an explosive atmosphere is present continuously, frequently, or for long periods.
• Category 2: Equipment that may be used in places where an explosive atmosphere is likely to occur occasionally.
• Category 3: Equipment for use in places where an explosive atmosphere is unlikely to occur and, if it does occur, will exist only for a short time.

Accordingly, for hazardous area zones, equipment categories should be applied as follows:

• Category 1: Equipment for zones 0, 1 and 2.
• Category 2: Equipment for zones 1 and 2.
• Category 3: Equipment for zone 2.

ATEX Directive: Risk Analysis and Design

The first step is risk analysis, which involves identifying potential hazards associated with using the equipment in an explosive atmosphere. The key elements of this stage are:

• Strength calculations (finite element analysis): The use of numerical methods to simulate and analyse structural strength. In explosive atmospheres, it is important to determine what explosion pressure may occur and how the equipment structure withstands these forces.
• Machine design: Selecting suitable components that can operate in an explosive atmosphere. In some cases, the entire control system must be implemented using pneumatics to avoid sparking and other ignition sources.

Selecting Suitable Components

Machine design in line with the directive requirements calls for:

• Selecting suitable components: Components must comply with ATEX Directive standards and be properly marked.
• Using protective technologies: In many cases, to ensure compliance with the directive, it is necessary to use advanced technologies such as protective systems, intrinsically safe devices, or increased-strength construction technologies.

Production and Quality Control

Production must be closely monitored to ensure that all equipment conforms to the design and meets the directive requirements. Key activities include:

• Testing and validation: Carrying out tests to ensure that equipment operates correctly in explosive atmospheres.
• Safety audits: Regular audits and reviews to ensure compliance with standards.

ATEX Directive: CE and Ex Marking: When and how they are used

CE marking:

CE marking (Conformité Européenne) is required for all products placed on the market in the European Economic Area (EEA). It indicates that the product meets the requirements of EU directives relating to safety, health and environmental protection.

Ex marking:

Ex marking is used for equipment and protective systems intended for use in potentially explosive atmospheres. This marking indicates that the product has been designed and manufactured in accordance with the requirements of Directive 2014/34/EU (ATEX).

When to use Ex marking alongside CE:

Ex marking is placed alongside CE marking in the following cases:

1. Products intended for use in potentially explosive atmospheres:
   • All equipment and protective systems that will be used in such atmospheres must bear Ex marking to indicate compliance with Directive 2014/34/EU (ATEX).
2. Conformity assessment procedure:
   • Products that have undergone the appropriate conformity assessment procedure (e.g. Module B + Module D, Module B + Module F) are entitled to bear Ex marking. These procedures confirm that the product meets the specific safety requirements related to explosion protection.
3. Technical documentation and the EU declaration of conformity:
   • The manufacturer must have technical documentation and an EU declaration of conformity showing that the product complies with the ATEX Directive. The Ex marking is then placed on the product together with the CE marking.
4. Special explosion protection symbol:
   • In addition to the CE and Ex markings, special explosion protection symbols are also applied to indicate the equipment group and category, as well as other information required by the ATEX Directive.

Examples of marking extensions according to IEC 60079:

• Example 1: Category 1 equipment (Group II):
  • CE 0123 Ex II 1 G Ex d IIC T4 Gb
    • CE: Marking showing conformity with EU directives.
    • 0123: Identification number of the notified body (if applicable).
    • Ex: Marking showing conformity with the ATEX Directive.
    • II: Equipment group (other than mining).
    • 1: Equipment category (very high level of protection).
    • G: For use in gas atmospheres.
    • Ex d: Type of protection (e.g. flameproof enclosure).
    • IIC: Gas group (hydrogen, acetylene).
    • T4: Temperature class (maximum surface temperature 135°C).
    • Gb: Equipment protection level (enhanced protection).
• Example 2: Category 2 equipment (Group I):
  • CE 0123 Ex I M2 Ex ib I Mb
    • CE: Marking showing conformity with EU directives.
    • 0123: Identification number of the notified body (if applicable).
    • Ex: Marking showing conformity with the ATEX Directive.
    • I: Equipment group (mining).
    • M2: Equipment category (high level of protection).
    • Ex ib: Type of protection (e.g. intrinsic safety).
    • I: Gas group (methane).
    • Mb: Equipment protection level (enhanced protection).

Possible extensions according to IEC 60079:

1. Types of protection:
   • Ex d: Flameproof enclosure.
   • Ex e: Increased safety.
   • Ex n: Non-sparking.
   • Ex p: Pressurization.
   • Ex ia/ib/ic: Intrinsic safety.
2. Gas groups:
   • I: Methane (mining).
   • IIA: Propane.
   • IIB: Ethylene.
   • IIC: Hydrogen, acetylene.
3. Temperature classes:
   • T1: 450°C.
   • T2: 300°C.
   • T3: 200°C.
   • T4: 135°C.
   • T5: 100°C.
   • T6: 85°C.
4. Equipment protection levels:
   • Ga: Highest level of protection (for use in Zone 0).
   • Gb: High level of protection (for use in Zone 1).
   • Gc: Basic level of protection (for use in Zone 2).

Using the CE and Ex markings together with the appropriate IEC 60079 extensions ensures clarity and product compliance with safety requirements in potentially explosive atmospheres.

ATEX Directive: Key Requirements

The Directive sets out a number of requirements that equipment and protective systems must meet:

• Design safety: Equipment must be designed to minimize the risk of explosion even if one of the protective measures fails.
• Materials: The materials used must be resistant to chemical reactions with the explosive atmosphere.
• CE marking: Every piece of equipment must bear the CE mark, demonstrating compliance with the requirements of the Directive.

Safety audits and ATEX harmonized standards play a key role in the certification process and in demonstrating compliance with the Directive.

ATEX Directive: Applications Across Industries

The ATEX Directive has broad application across many industrial sectors:

• Petrochemical industry: Used in refineries and drilling platforms.
• Mining: Equipment used in mines must meet stringent safety standards.
• Grain mills: Requirements for production process automation and safety.

In each of these industries, the role of the industrial automation integrator and specialists in PLC programming is crucial to ensuring compliance with the Directive.

ATEX Directive: Harmonized Standards

Under the ATEX Directive, there are many harmonized standards that ensure consistency and safety in industrial automation. Standards in the EN 60079-x series are particularly important for explosion protection. Below is an overview of the key standards in this series:

1. EN 60079-0: Explosive atmospheres – Part 0: Equipment – General requirements
   • Specifies the general requirements for the design and testing of equipment intended for use in explosive atmospheres.
2. EN 60079-1: Explosive atmospheres – Part 1: Equipment protection by flameproof enclosures “d”
   • Applies to equipment designed to prevent flames from propagating into the explosive atmosphere.
3. EN 60079-2: Explosive atmospheres – Part 2: Equipment protection by pressurized enclosure “p”
   • Sets out the principles for protecting equipment by maintaining gas overpressure inside the enclosure, preventing the explosive atmosphere from entering.

Examples of Harmonized Standards Other than EN 60079-x

In addition to the EN 60079-x series, there are other important harmonized standards related to the ATEX Directive:

1. EN 1834-1:2002: Reciprocating internal combustion engines – Safety requirements for the design and construction of engines for use in potentially explosive atmospheres – Part 1: Group II engines for use in flammable gas and vapour atmospheres
   • Sets out safety requirements for the design and construction of engines used in explosive atmospheres.
2. EN 13463-1:2009: Non-electrical equipment for potentially explosive atmospheres – Part 1: Basic methods and requirements
   • Specifies the basic requirements and protection methods for non-electrical equipment intended for use in explosive atmospheres.
3. EN 13760:2022-04: LPG equipment and accessories – LPG filling systems for light and heavy-duty vehicles – Nozzles, test requirements and dimensions
   • Concerns the safety of the design and operation of LPG filling equipment used in explosive atmospheres.

The ATEX Directive is a key element in ensuring safety in potentially explosive atmospheres. Through appropriate practices, certification, and the implementation of advanced technologies, companies can effectively minimize the risk of explosions and provide safe working conditions. In industrial automation, the directive is particularly important because it enables production processes to be managed safely and efficiently. Harmonized standards such as EN 60079-x play a key role in achieving these objectives.