ATEX Module C2 Explained

ATEX Module C2 is a conformity assessment procedure defined in Directive 2014/34/EU that verifies whether production equipment continues to conform to the product type approved under ATEX Module B (EU-Type Examination). Unlike Module B, which evaluates the technical design of a representative product, Module C2 focuses on production by requiring supervised product checks performed at random intervals by an ATEX Notified Body.

Module C2 is commonly selected by manufacturers that have completed EU-Type Examination but do not operate a certified production quality assurance system under Module D. Instead of auditing the manufacturer's quality management system, the Notified Body periodically inspects and tests randomly selected products to confirm continued conformity with the approved type.

This article explains what ATEX Module C2 is, how supervised product checks are performed, when Module C2 is used, and how it supports compliance with Directive 2014/34/EU.

Quick Answer

What Is ATEX Module C2?

ATEX Module C2 is one of the conformity assessment modules established by Directive 2014/34/EU for certain categories of equipment intended for use in potentially explosive atmospheres.

Under this procedure, the manufacturer remains responsible for ensuring that production equipment conforms to the approved product type. An ATEX Notified Body provides independent oversight by carrying out supervised product checks at random intervals throughout production.

The purpose of Module C2 is to provide confidence that products manufactured after the EU-Type Examination remain technically equivalent to the certified type approved under Module B.

Why Is Module C2 Required?

Passing an EU-Type Examination demonstrates that a representative product design complies with the ATEX Directive. However, manufacturers must also demonstrate that products manufactured later continue to match the approved design.

Module C2 addresses this requirement by introducing independent surveillance of production through periodic inspections and product verification performed by an ATEX Notified Body.

This approach helps ensure that:

• Production equipment remains consistent with the approved type.
• Changes in manufacturing do not affect explosion protection.
• Products placed on the European market continue to comply with Directive 2014/34/EU.
• Independent oversight is maintained throughout production.

Who Performs Module C2?

Module C2 requires participation by an ATEX Notified Body designated under Directive 2014/34/EU.

The manufacturer performs internal production control, while the Notified Body independently conducts supervised product checks at random intervals. These inspections provide additional assurance that production remains consistent with the equipment approved during Module B.

The Notified Body records the results of its inspections and determines whether the sampled products continue to satisfy the applicable ATEX requirements.

When Is Module C2 Used?

Module C2 is typically used after successful completion of ATEX Module B (EU-Type Examination). It is one of several conformity assessment routes available for equipment requiring third-party involvement under the ATEX Directive.

Manufacturers may select Module C2 when it is appropriate for their product category and conformity assessment strategy, particularly when they do not use production quality assurance under Module D.

How Does the ATEX Module C2 Process Work?

ATEX Module C2 combines the manufacturer's internal production control with independent supervision by an ATEX Notified Body. After the equipment has successfully completed the EU-Type Examination under Module B, the Notified Body periodically verifies that production remains consistent with the approved product type.

A typical Module C2 conformity assessment process includes:

1. The manufacturer completes ATEX Module B and obtains an EU-Type Examination Certificate.
2. The manufacturer implements internal production control to ensure all products conform to the approved type.
3. An ATEX Notified Body selects product samples at random intervals.
4. The selected products are inspected and, where appropriate, tested.
5. The Notified Body confirms whether the sampled products continue to comply with the approved type.
6. If nonconformities are identified, corrective actions must be implemented before production continues.

This process provides ongoing confidence that production remains consistent after the initial type examination.

What Does the Notified Body Check?

During Module C2 surveillance, the ATEX Notified Body evaluates whether production equipment continues to match the product type approved during Module B.

The assessment may include:

• Verification of explosion protection marking.
• Inspection of product construction.
• Dimensional verification.
• Review of critical safety components.
• Functional testing where applicable.
• Verification that no unauthorized design changes have been introduced.
• Confirmation that products continue to comply with the approved technical documentation.

The scope of inspection depends on the product, the applicable harmonized standards, and the surveillance plan established by the Notified Body.

What Happens if Nonconformities Are Found?

If the Notified Body identifies products that no longer conform to the approved type, the manufacturer must investigate the cause and implement appropriate corrective actions.

Depending on the nature of the nonconformity, actions may include:

• Correction of manufacturing processes.
• Replacement of nonconforming components.
• Additional product testing.
• Review of production controls.
• Suspension of affected products until compliance has been restored.

Significant nonconformities may affect the manufacturer's ability to continue using the selected conformity assessment route until the issues have been resolved.

Module C2 Compared with Module D

Manufacturers often choose between Module C2 and Module D after completing Module B. Although both procedures support continued conformity with the approved product type, they use different approaches.

Module C2	Module D
Random supervised product checks.	Production quality assurance system.
Product-focused surveillance.	Quality system-focused assessment.
Periodic inspection of selected products.	Periodic audit of manufacturing processes.
Suitable for manufacturers using internal production control.	Suitable for manufacturers operating an approved production quality system.

The appropriate conformity assessment route depends on the manufacturer's production processes, quality management system, and the applicable requirements of Directive 2014/34/EU.

Benefits of ATEX Module C2

Module C2 provides manufacturers with a conformity assessment route that combines internal production control with independent third-party oversight.

• Maintains confidence in ongoing production.
• Provides independent surveillance by an ATEX Notified Body.
• Confirms continued conformity with the approved type.
• Supports compliance with Directive 2014/34/EU.
• Reduces the risk of production deviations affecting explosion protection.
• Enhances confidence for customers and regulatory authorities.

By introducing periodic supervised product checks, Module C2 helps ensure that explosion-protected equipment placed on the European market continues to meet the technical requirements established during the EU-Type Examination.

Common Misunderstandings About ATEX Module C2

Module C2 Replaces Module B

No. Module C2 cannot be used independently. It is a follow-up conformity assessment procedure that relies on a valid EU-Type Examination Certificate issued under ATEX Module B.

Every Product Is Tested by the Notified Body

No. Under Module C2, the ATEX Notified Body performs supervised product checks at random intervals. The manufacturer remains responsible for internal production control and ensuring that all products conform to the approved type.

Module C2 Audits the Entire Quality Management System

No. Module C2 focuses on the conformity of finished products rather than auditing the manufacturer's production quality system. Manufacturers seeking quality system assessment normally follow Module D or Module E, depending on the applicable conformity assessment route.

Module C2 Eliminates the Need for Internal Production Control

No. The manufacturer remains fully responsible for maintaining effective production controls. The Notified Body's supervision complements, but does not replace, the manufacturer's own quality assurance activities.

Frequently Asked Questions (FAQ)

What is ATEX Module C2?

ATEX Module C2 is the conformity assessment procedure known as Conformity to Type Based on Internal Production Control Plus Supervised Product Checks at Random Intervals. It combines the manufacturer's internal production control with independent surveillance by an ATEX Notified Body.

Is Module C2 used without Module B?

No. Module C2 is intended to follow a successful EU-Type Examination performed under ATEX Module B.

Who performs the supervised product checks?

An ATEX Notified Body designated under Directive 2014/34/EU performs the supervised product checks and verifies that sampled products continue to conform to the approved type.

Does Module C2 require a certified quality management system?

No. Unlike Module D, Module C2 does not require assessment of the manufacturer's production quality management system. Instead, it relies on internal production control supported by independent product surveillance.

What happens if a sampled product fails inspection?

If a sampled product does not conform to the approved type, the manufacturer must investigate the cause, implement corrective actions, and restore compliance before affected products are placed on the market.

Conclusion

ATEX Module C2 provides an effective conformity assessment route for manufacturers that have completed EU-Type Examination under Module B and maintain internal production control. By combining the manufacturer's responsibility for production with independent supervised product checks performed by an ATEX Notified Body, Module C2 helps ensure that products placed on the European market remain consistent with the approved type.

Understanding the relationship between Module B and Module C2 also helps manufacturers select the most appropriate conformity assessment route while maintaining compliance with Directive 2014/34/EU throughout the production lifecycle.

Technical Review

References

• Directive 2014/34/EU of the European Parliament and of the Council.
• European Commission – ATEX Guidelines for Directive 2014/34/EU.
• EN IEC 60079 Series – Explosive Atmospheres.
• Blue Guide on the Implementation of EU Product Rules.
• ISO/IEC 80079 Series.