Classes and Divisions Compared to ATEX/IECEx Zones

When dealing with hazardous environments—whether in Europe, the U.S., or any other part of the world—knowing the relevant safety regulations and certifications is crucial. Two of the most widely recognized systems for certifying equipment in explosive atmospheres are ATEX and IECEx, both of which use a “zoning” classification.

In contrast, the United States and Canada traditionally use a “Classes and Divisions” system. Though both frameworks serve the same fundamental purpose—ensuring the safety of people and equipment in potentially explosive environments—understanding their differences is key to compliance and safety.

ATEX and IECEx Zones: The Global Standard

The ATEX Directive, which is mandatory within the European Economic Area (EEA), is derived from two European Union Directives aimed at controlling explosive atmospheres.

IECEx, an international certification system governed by the International Electrotechnical Commission (IEC), is recognized in many countries around the world. These two systems share the same zone classification structure to categorize the risk level of explosive atmospheres.

In both ATEX and IECEx frameworks, environments are divided into zones based on the frequency and duration of the presence of explosive atmospheres:

• Zone 0 (Gas) / Zone 20 (Dust): Explosive atmospheres are continuously present.
• Zone 1 (Gas) / Zone 21 (Dust): Explosive atmospheres are likely to occur occasionally.
• Zone 2 (Gas) / Zone 22 (Dust): Explosive atmospheres are not likely to occur under normal operation and, if they do, will exist only for a short period.

ATEX goes further by defining equipment into categories based on the level of protection required:

• Category 1: Suitable for Zones 0 and 20, offering the highest level of protection.
• Category 2: Designed for Zones 1 and 21, providing medium-level protection.
• Category 3: For Zones 2 and 22, offering normal protection levels.

IECEx, on the other hand, uses Protection Levels (PLs) rather than categories, denoted by ‘a’, ‘b’, and ‘c’, which align with ATEX’s equipment categories.

The Classes and Divisions System: North American Approach

In the United States and Canada, hazardous locations are traditionally classified using the Classes and Divisions system. This system divides environments based on the type of hazard (Class) and the likelihood of the presence of hazardous materials (Division).

• Class I: Deals with explosive gases or vapors.
• Class II: Concerns explosive dust.
• Class III: Involves ignitable fibers or flyings.

Divisions further describe the conditions of hazard presence:

• Division 1: Hazardous materials are present under normal operating conditions.
• Division 2: Hazardous materials are present only in abnormal conditions, such as equipment failure.

Comparing Classes and Divisions to Ex Zones

The ATEX/IECEx Zones and the North American Classes and Divisions system both categorize hazardous locations but approach the classification differently. ATEX/IECEx Zones focus on the frequency and duration of explosive atmospheres, with Zone 0 (or Zone 20 for dust) representing continuous presence of explosive materials, Zone 1 (or Zone 21) for occasional presence, and Zone 2 (or Zone 22) for rare and short-term presence.

In contrast, the Classes and Divisions system divides environments by the type of hazard, with Class I covering gases, Class II covering dust, and Class III covering fibers, and by the likelihood of hazardous material presence, with Division 1 indicating normal operating conditions and Division 2 indicating abnormal or occasional conditions.

While Zones 0 and 1 in ATEX/IECEx are roughly equivalent to Class I, Division 1 (continuous or frequent gas hazard), Zone 2 corresponds to Class I, Division 2 (hazard present only under abnormal conditions).

The ATEX/IECEx system is more detailed, offering finer distinctions in hazard frequency, whereas the Classes and Divisions system is broader and simpler in its classification.

Zones vs. Divisions: Key Differences

1. Granularity:
   • ATEX and IECEx systems provide more granular classifications by separating hazardous areas into zones (e.g., 0, 1, 2 for gas, 20, 21, 22 for dust).
   • The Classes and Divisions system is simpler, dividing areas into only two categories, Division 1 and Division 2, based on hazard presence.
2. Flexibility:
   • The ATEX system allows manufacturers to self-certify equipment for use in Zone 2 (Category 3), meaning less stringent certification requirements compared to Zones 0 and 1. However, self-certification is not applicable in the IECEx system, which always requires a Certificate of Conformity (CoC) from an accredited body.
   • In the U.S., equipment for Class I, Division 2 areas (comparable to Zone 2) often requires less rigorous certification.
3. Global Application:
   • ATEX is mandatory across the European Union, whereas IECEx is a voluntary global system recognized in many countries outside of Europe, including Australia, Singapore, and Israel.
   • The Classes and Divisions system is specific to North America, although the U.S. has also started recognizing IECEx in some areas. However, equipment certified under IECEx cannot be used in North America if the area is classified by classes and divisions.
4. Markings and Certifications:
   • ATEX certification involves the use of the CE marking, along with detailed equipment classifications. IECEx uses a different marking system, which includes a certificate issued by an IECEx Certification Body (ExCB).
   • In the Classes and Divisions system, equipment is marked with the relevant class and division, along with information about its suitability for specific hazardous environments.

Geographic Acceptance of Explosion-Proof Certifications

While ATEX, IECEx, and the North American Classes/Divisions systems are widely recognized, it’s crucial to understand how these certifications are accepted in different regions of the world. Companies operating in hazardous areas must be aware of the applicable regulations in their country of operation.

Incorporating this list of geographic acceptance further clarifies how different certifications are applied globally. This serves as a quick reference for businesses to align their equipment certification with local requirements, ensuring operational safety and compliance across multiple jurisdictions.

Additionally, for businesses expanding across borders, understanding the nuances of these certifications can streamline the process of selecting appropriate equipment, reducing the risk of non-compliance, and avoiding costly operational delays.

Why is it important to choose between different hazardous area certifications?

For companies operating internationally, knowing which certification applies to your region is essential. It helps you not only ensure compliance but also instill confidence in your safety measures. With our extensive knowledge and resources on global Ex compliance, we can assist you in making informed decisions.

Whether you need ATEX certification for the EEA, IECEx for global operations, or NEC/CEC compliance for North America, our experts can guide you through the complexities of Ex standards and ensure that your equipment is certified for safe operation worldwide.

Bridging the Gap: Harmonization and Challenges

As the world continues to globalize, the need for international harmonization of safety standards has become more pronounced. While ATEX and IECEx certifications are becoming increasingly aligned—thanks to their shared technical standards since 2005—the North American Classes and Divisions system remains a separate entity, despite growing recognition of IECEx.

However, one thing remains constant: mixing zones with classes and divisions is forbidden. Equipment certified under one system cannot be used in areas classified by the other without undergoing separate certification.

Conclusion: Choosing the Right System

When selecting equipment for use in hazardous areas, the key consideration is not which system is “better” but which one is required by law in your region. ATEX is compulsory across Europe, IECEx is increasingly recognized as the global standard, and North America retains its Classes and Divisions framework. Understanding these systems’ nuances can help ensure compliance and the safety of both personnel and operations in hazardous environments.