Conformity Assessment is the complete process by which a manufacturer evaluates and documents that a product meets all essential requirements of the applicable EU regulations and directives. The outcome of a conformity assessment is the Declaration of Conformity and the right to affix the CE mark. It is not a single event — it is an engineering and documentation programme that runs from product design through to post-market surveillance.
The Modular System
The EU uses a standardised set of conformity assessment modules, each representing a different level of third-party involvement. The applicable directive specifies which modules are available for a given product. Manufacturers choose the appropriate module or combination of modules.
| Module | Name | Third-party required? | Description |
|---|---|---|---|
| A | Internal production control | ❌ Self-declaration | Manufacturer designs, tests internally, issues DoC. Most common for EMC, LVD, RED with harmonised standards. |
| B | EU Type Examination | ✅ NB required | NB examines design and prototype. Issues EU Type Examination Certificate. Used before modules C, D, E, F. |
| C | Conformity to type | ❌ or ✅ depending on C1/C2 | Manufacturer declares each unit conforms to the EU Type. |
| C2 | Conformity to type with product checks | ✅ NB required | NB performs random product checks. |
| D | Production quality assurance | ✅ NB required | NB approves QMS for manufacturing phase. |
| E | Product quality assurance | ✅ NB required | NB approves QMS covering final inspection. |
| F | Product verification | ✅ NB required | NB tests every unit or statistical samples. |
| G | Unit verification | ✅ NB required | NB tests each individual unit. For one-off or small-batch productions. |
| H | Full quality assurance | ✅ NB required | NB approves complete QMS (design + manufacturing). Highest level. |
Conformity Assessment Routes by Directive
| Directive | Available Modules | Most Common Route for B2B Hardware |
|---|---|---|
| EMC (2014/30/EU) | A, B+C, B+D, B+E, B+F, G, H | Module A — self-declaration using harmonised standards |
| LVD (2014/35/EU) | A, B+C, B+D, B+E, B+F, G, H | Module A — self-declaration with test reports |
| RED (2014/53/EU) | A, B+C, B+D, B+E, B+F, G, H | Module A — if harmonised standards used from OJEU list |
| RED Delegated Act | A, B+C, B+D, B+E, B+F, G, H | Module A — using EN 18031 series |
| CRA (2024/2847) | A (Default), B+C, H (Important/Critical class) | Module A for most products; B+C or H for Important/Critical class |
| Machinery (2023/1230) | A, B+C, B+D, B+F, B+G, H | Module B+C or H for safety-critical functions |
| MDR (2017/745) | Class I: A; Class IIa: A+NB; IIb/III: B+D or B+F | B+D or B+F for most CE-marked medical devices |
Presumption of Conformity
When a manufacturer applies harmonised standards (EN standards listed in the Official Journal of the EU, OJEU), they benefit from the presumption of conformity — a legal presumption that compliance with the standard implies compliance with the essential requirements of the applicable directive. This is the mechanism that enables self-declaration (Module A): the standard does the regulatory heavy lifting, and the accredited laboratory test report provides the evidence.
If no harmonised standard exists or covers the product (common for emerging technologies), the manufacturer must directly demonstrate compliance with the directive’s essential requirements — a more complex and typically NB-assisted process.
Common Conformity Assessment Mistakes
- Selecting the wrong module — using Module A when the directive requires NB involvement (e.g., Annex I Machinery with safety functions)
- Using outdated standards — harmonised standards in the OJEU list are periodically replaced; a test report citing a withdrawn standard no longer supports the presumption of conformity
- Treating conformity assessment as a one-time event — product changes, SBOM updates, or new CVEs may require re-assessment
- Confusing “tested to” with “certified to” — a test report from an accredited laboratory demonstrates compliance with a standard; compliance with the directive’s essential requirements is the manufacturer’s own declaration
Official References
- Decision No 768/2008/EC — New Legislative Framework (NLF), Annex II: Conformity Assessment Modules — EUR-Lex (defines all conformity assessment modules A through H)
- Regulation (EC) No 765/2008 — Market surveillance and CE marking — EUR-Lex (the framework regulation underpinning the CE marking system)