ATEX Module D Explained
ATEX Module D is the conformity assessment procedure known as Conformity to Type Based on Quality Assurance of the Production Process under Directive 2014/34/EU.
Module D is a production-stage procedure used with an EU-Type Examination where applicable. The manufacturer operates an approved quality system covering production, final product inspection, and testing so that manufactured products remain conforming to the type described in the EU-Type Examination Certificate.
An ATEX Notified Body assesses the manufacturer's quality system and carries out surveillance to verify that the approved system continues to be maintained and applied effectively. The manufacturer remains responsible for ensuring and declaring conformity of the products. ([eur-lex.europa.eu](https://eur-lex.europa.eu/eli/dir/2014/34/oj))
What Is ATEX Module D?
Module D is defined in Annex IV of Directive 2014/34/EU.
Its purpose is to establish conformity to the approved product type through quality assurance of the production process.
Under Module D, the manufacturer must:
- Operate an approved quality system for production.
- Include final product inspection and testing within that system.
- Maintain documented quality procedures and records.
- Ensure that manufactured products conform to the type described in the EU-Type Examination Certificate.
- Remain responsible for declaring conformity.
The Notified Body independently assesses the quality system and conducts surveillance after approval. ([eur-lex.europa.eu](https://eur-lex.europa.eu/eli/dir/2014/34/oj))
Where Does Module D Fit in the ATEX Process?
Module D is concerned with production conformity, not the initial technical examination of the product type.
Where Module B is applicable, the relationship can be summarized as:
| Stage | Module | Function |
|---|---|---|
| Type examination | Module B | Examines the technical design and representative type |
| Production conformity | Module D | Ensures production remains conforming through an approved production quality system |
Module B establishes the approved type. Module D provides the production-quality mechanism for maintaining conformity with that type.
The European Commission describes Module D as a production procedure that follows Module B and uses quality assurance of the production process to ensure conformity to the EU type.
What Does Module D Require From the Manufacturer?
The manufacturer must operate an approved quality system for production, final product inspection, and testing.
The quality system documentation must allow the quality procedures and records to be consistently understood and applied.
Under Annex IV, the system must address, as appropriate:
- Quality objectives.
- Organizational structure and quality responsibilities.
- Manufacturing techniques and processes.
- Quality control and quality assurance activities.
- Examinations and tests before, during, and after manufacture.
- Frequency of inspections and tests.
- Quality records.
- Inspection and test data.
- Calibration data.
- Personnel qualification records.
- Methods for monitoring product quality.
- Methods for monitoring effective operation of the quality system.
These requirements are specifically connected to maintaining conformity of the manufactured products with the approved type. ([eur-lex.europa.eu](https://eur-lex.europa.eu/eli/dir/2014/34/oj))
What Does the Manufacturer Submit to the Notified Body?
The manufacturer submits an application for assessment of its quality system to a Notified Body of its choice for the products concerned.
The application includes information such as:
- Manufacturer identification and address.
- The products covered by the quality system.
- Description of the relevant manufacturing and quality-control processes.
- Examinations and tests performed before, during, and after manufacture.
- Quality records and record-keeping arrangements.
- Methods used to monitor product quality.
The Notified Body uses this information to determine whether the quality system satisfies the applicable Module D requirements.
How Does the ATEX Module D Process Work?
A simplified Module B + D process is:
- The product type undergoes the applicable EU-Type Examination under Module B.
- The manufacturer establishes the production quality system for the relevant products.
- The manufacturer submits the quality-system application to an ATEX Notified Body.
- The Notified Body assesses the quality system.
- If the requirements are satisfied, the Notified Body approves the quality system.
- The manufacturer operates the approved system during production.
- The Notified Body conducts surveillance to verify continued compliance.
- The manufacturer continues to declare conformity for products manufactured under the approved system.
The exact scope and implementation depend on the products and the quality system being assessed.
What Does the Notified Body Assess?
The Notified Body assesses whether the manufacturer's quality system is capable of ensuring that products remain conforming to the approved type and the applicable ATEX requirements.
The assessment can cover:
- Quality-system documentation.
- Production procedures.
- Inspection and testing procedures.
- Incoming materials and components.
- Production controls.
- Final inspection and testing.
- Calibration and measurement controls.
- Personnel competence.
- Quality records.
- Nonconforming-product controls.
- Corrective actions.
- Engineering and manufacturing changes.
- Traceability where relevant to conformity.
The objective is not simply to determine whether the manufacturer has a quality manual. The Notified Body evaluates whether the system actually provides assurance that production remains consistent with the approved type.
Is Module D the Same as ISO 9001?
No.
Module D is an ATEX conformity assessment procedure. It focuses specifically on the production quality system as it relates to products covered by Directive 2014/34/EU.
A manufacturer may already have an ISO 9001 quality management system, but ISO 9001 certification does not automatically demonstrate compliance with Module D.
The Notified Body must assess the relevant quality system against the requirements of Module D and its relationship to the ATEX products covered by the procedure.
The Directive allows conformity to the quality-system requirements to be presumed for elements complying with the corresponding specifications of relevant harmonised standards, but the Module D assessment remains an ATEX conformity-assessment activity. ([eur-lex.europa.eu](https://eur-lex.europa.eu/eli/dir/2014/34/oj))
What Happens After Module D Approval?
Module D does not end when the initial quality-system assessment is completed.
The manufacturer must continue operating the approved quality system, and the Notified Body conducts surveillance to verify that the system remains maintained and applied.
Under Annex IV, surveillance includes:
- Periodic audits.
- Review of relevant quality records.
- Verification that the approved quality system continues to operate.
- Audit reports provided to the manufacturer.
The Notified Body may also make unexpected visits. During such visits, it may carry out or arrange product tests when necessary to verify that the quality system is functioning correctly. ([eur-lex.europa.eu](https://eur-lex.europa.eu/eli/dir/2014/34/oj))
What Happens if the Quality System Is Not Maintained?
If the manufacturer no longer satisfies the requirements of the approved quality system, the Notified Body can require corrective action and apply the procedures associated with maintaining the quality-system approval.
Where significant nonconformities remain unresolved, the quality-system approval can be subject to suspension or withdrawal under the applicable procedures.
This is why Module D should be understood as an ongoing production conformity arrangement, rather than a one-time factory audit.
Module D vs Module C2
Module D and Module C2 both address production conformity, but they use different mechanisms.
| Module D | Module C2 |
|---|---|
| Quality assurance of the production process | Internal production control plus supervised product checks at random intervals |
| Focuses on the production quality system | Focuses on supervised checks of production output |
| Requires an approved quality system | Does not use approval of a production quality system as its conformity mechanism |
| Notified Body assesses and surveils the quality system | Notified Body performs supervised product checks at random intervals |
| System-based production assurance | Product-check-based production assurance |
Neither description should be interpreted as a general commercial ranking. The applicable conformity assessment route is determined by the Directive and the product's circumstances.
Module D vs Module E
Module D and Module E are both quality-assurance-based production conformity procedures, but they cover different parts of the production process.
| Module D | Module E |
|---|---|
| Quality assurance of the production process | Quality assurance of the product |
| Covers production and final product inspection/testing | Focuses on final product inspection and testing |
| Production process is central to the quality system | Product quality controls are central to the quality system |
| Used as a production conformity route following Module B where applicable | Used as a product-quality conformity route following Module B where applicable |
Directive 2014/34/EU defines Module E separately as Conformity to Type Based on Product Quality Assurance.
Does Module D Replace Module B?
No.
Module D is a conformity-to-type procedure. It is based on the type described in the EU-Type Examination Certificate.
Where Module B is required as part of the applicable route, Module D operates as the production-stage procedure associated with that approved type.
In simple terms:
Module B = examination of the type
Module D = production quality assurance for conformity to that type
Does Module D Inspect Every Product?
No.
Module D does not operate like a procedure in which a Notified Body individually verifies every manufactured unit.
The manufacturer operates the approved production quality system, including the required production controls, inspections, and tests. The Notified Body then performs surveillance of the system.
This differs from product-verification procedures such as Module F, where conformity of individual products is the central mechanism.
What Should Engineers and Procurement Teams Check?
When a vendor claims that an ATEX product is covered by Module D, the following checks are useful:
- Identify the EU-Type Examination Certificate associated with the product.
- Check that the manufacturer and product identification match.
- Identify the Notified Body responsible for Module D.
- Confirm that the Notified Body is notified for Directive 2014/34/EU and the relevant conformity assessment activity.
- Check that the Module D quality-system approval covers the relevant products.
- Check the relationship between the Module D approval and the applicable EU-Type Examination Certificate.
- Review the EU Declaration of Conformity for consistency with the certification package.
- Check the product marking against the certified type.
- Check any applicable special conditions for safe use.
For a technical bid, a useful distinction is that a Module D approval is not the same document as the EU-Type Examination Certificate. The two documents address different stages of the conformity assessment process.
Common Misunderstandings About ATEX Module D
Module D Is the Same as ISO 9001
No. ISO 9001 is a general quality management standard. Module D is an ATEX conformity assessment procedure specifically concerned with production conformity to an approved type.
Module D Replaces Module B
No. Module D establishes conformity to the type described in the EU-Type Examination Certificate. Where Module B is part of the applicable route, D follows that type examination.
Module D Means the Notified Body Tests Every Product
No. The primary mechanism is assessment and surveillance of the manufacturer's approved production quality system. The Notified Body may perform product tests when appropriate, including during unexpected visits, but Module D is not an individual-product verification procedure. ([eur-lex.europa.eu](https://eur-lex.europa.eu/eli/dir/2014/34/oj))
Module D Is a One-Time Factory Audit
No. The Notified Body performs periodic surveillance to verify that the manufacturer maintains and applies the approved quality system.
The Notified Body Takes Responsibility for Product Quality
No. The manufacturer remains responsible for ensuring and declaring that the products conform to the approved type and applicable ATEX requirements.
Module D Covers Only Final Inspection
No. Module D covers the production quality process as well as final product inspection and testing. This distinguishes it from Module E, which focuses on product quality assurance. ([eur-lex.europa.eu](https://eur-lex.europa.eu/eli/dir/2014/34/oj))
Frequently Asked Questions
What is ATEX Module D?
ATEX Module D is Conformity to Type Based on Quality Assurance of the Production Process. It requires the manufacturer to operate an approved quality system for production, final product inspection, and testing.
Who assesses the Module D quality system?
An ATEX Notified Body assesses the manufacturer's quality system and performs surveillance after approval.
Does Module D require Module B?
Module D is a conformity-to-type procedure based on the type described in an EU-Type Examination Certificate. Where Module B is required by the applicable conformity assessment route, D follows that type examination.
Does Module D require surveillance?
Yes. The Notified Body performs periodic audits and can conduct unexpected visits under the conditions specified in Annex IV. ([eur-lex.europa.eu](https://eur-lex.europa.eu/eli/dir/2014/34/oj))
What is the difference between Module D and C2?
Module D uses an approved production quality system as the conformity mechanism. Module C2 uses internal production control combined with supervised product checks at random intervals.
What is the difference between Module D and E?
Module D covers quality assurance of the production process, including production and final product inspection/testing. Module E focuses on product quality assurance, particularly final product inspection and testing.
Is Module D the same as a factory acceptance test?
No. A factory acceptance test is a project or procurement activity. Module D is a formal ATEX conformity assessment procedure concerning the manufacturer's production quality system.
Conclusion
ATEX Module D is the production-quality route for establishing conformity to an approved product type. Instead of relying primarily on random checks of finished products, Module D requires the manufacturer to operate an approved quality system covering production, final inspection, and testing.
An ATEX Notified Body assesses that quality system and performs ongoing surveillance to verify that it remains maintained and effective. The manufacturer retains responsibility for ensuring and declaring that the products conform to the approved type and applicable ATEX requirements.
The practical distinction within the ATEX module cluster is:
Module B → establishes the approved type.
Module D → controls production through an approved production quality system.
Join the conversation