Drafting homegrown European standards for citation in the OJEU

This page provides guidance to Technical Bodies and Working Groups (WGs) on horizontal aspects to be considered when preparing harmonized European standards in support of EU harmonization legislation intended to be cited in the Official Journal of the European Union (OJEU). Information on the HAS process and how to interact with the HAS consultants can be found on the page HAS assessment process.
Regulation (EU) No 1025/2012 on European standardization defines a harmonized standard as “a European standard adopted on the basis of a request made by the Commission for the application of Union harmonization legislation”.



The starting point for the development of a harmonized standard (hEN) is to assess whether it is in the scope of the relevant EU harmonization legislation and whether the standard is covered by a Standardization Request (SReq) or mandate which was accepted by the Technical Boards (BTs). The correct information whether a standard is mandated is crucial in the next steps of the process.

The adoption of a New Work Item (NWI) is required for the development of a new or revised harmonized standard. When filling the New Work Item proposal form, the proposal shall include the applicable mandate/SReq and the relevant EU Directive/Regulation. If mandated, the NWI will be approved according to Clause 6.4 of CEN-CENELEC Internal Regulations - Part 2 (IR2). 

If the Technical Body decides to first adopt a Preliminary Work Item for the development of a harmonized standard, the proposal shall also include information about the mandate/SReq and EU Directive/Regulation.

In accordance with the principles of the Flexible standards development process, for each project, target dates for delivering the draft to Enquiry (stage 30.99) and FV (stage 45.99) are established according to the needs. BT recommended Technical Bodies (TBs) to allocate at least 50 weeks for the stage for the Drafting of prEN (from the NWI approval to the submission to Enquiry) and the remaining 18 weeks for the stage for the Handling of comments after Enquiry and for the drafting of FprEN. The rationale is that with the new process the compliance will be already sought at Enquiry stage and enough weeks have to be allocated to this purpose. In case of early delivery, all saved time before stage 30.99 will be added to the second stage for TC work (up to stage 45.99).

The WG Convenor, with the support of the Qualified Support, is responsible for filling the NWI form, which shall be submitted to the Technical Committee (TC) Secretary. The TC Secretary will carry out a final check of the filled NWI form and launch the Committee Internal Balloting (CIB) for the approval of the NWI. The approval of a NWI is a BT delegated decision to the TC (see the acceptance criteria for the approval of a mandated NWI in clause 6.4 of IR2).


2.1 General rules for the preparation of harmonized standards (hENs)

In addition to the generic rules, sector specific guidance can be found under 5.

When drafting homegrown harmonized standards in support of EU legislation, Technical Bodies shall check their compliance against a dedicated Common Checklist.

The Common Checklist contains aspects that shall be considered by Technical Bodies and Working Groups when drafting harmonized standards in support of EU legislation.

CCMC will reject the submission of a (final) drafts harmonized standard if the completed Common Checklist or relevant supporting documents/justifications are not submitted.

When drafting homegrown harmonized standards, the use of the Common Checklist by the Technical Bodies and Working Groups is mandatory.

The Technical Bodies shall consider the below aspects when drafting harmonized standards.

2.1.1 Other general rules

The TC secretary shall confirm that the draft standard is covered by a Standardization Request or mandate and that the information is correctly displayed on Projex-Online. If not, a possible way forward is to propose the European Commission to add this work item in a (revised) Standardization Request. In case the information on Projex-Online on a Standardization Request, mandate or the EU legislation needs to be corrected, the TC Secretary needs to contact the CCMC Project Manager.

Due to the implementation of the Innovative Process on projects launched for approval as of 2023-10-01, the Mature Draft HAS assessment is mandatory only for the Homegrown harmonized standards, and so the comments from the HAS consultant shall be addressed by the WG before the Enquiry stage. The comments of the WG shall be filled in the last column of Part B3 of the HAS assessment report (‘Comments/Justifications from Technical Body’) to indicate how the comments of the consultant have been addressed.

Furthermore, any requirements covered in the harmonized standard that are not linked with legal requirements of EU legislation must be covered in separate clauses and not tackled in the Annex Z.

2.1.2 European Foreword

When a TC is revising a standard, the significant changes with respect to the previous edition must be precisely described in the Foreword of the standard. The list of the significant changes with respect to the previous edition is an important element useful to standard users. It should not be vague. When the list of significant technical changes is extensive, it may be included in an Informative Annex. A reference to that annex shall be included in the Foreword, preferably after the generic sentence that refers to the superseded document.

The Foreword text to be used can be found in CEN simple template for drafting standards.

2.1.3 Scope

The scope of the harmonized standard shall be concise and clear and worded as a series of statements of facts. In line with CEN-CENELEC Internal Regulations - Part 3 (IR3), the scope shall not include requirements, permissions or recommendations. The scope shall be consistent regarding content covered by the standard.

However, the scope of the standard could be broader than the relationship between the standard and the requirements of the EU legislation.

2.1.4 Normative references

CEN-CENELEC Internal Regulations – Part 3 include provisions on the use of normative references (see Guidance on normative references and the Guidance on normative references in harmonized standards).

The standards listed in Clause 2 must be normatively referenced within the text. They must be cited in the text in such a way that some or all of their content constitutes requirements of the document, for instance with a “shall”.

The normative references in Clause 2 and in the body of the standard should be dated, active and published. Non-dated normative references are possible if:

  • The normative reference is not relevant for compliance with Essential Requirements, or
  • The normative reference is relevant for compliance with Essential Requirements but the implications of modifications to the referenced document for the compliance with Essential Requirements have been duly considered (to be explained in the justification).

As a general principle, all the normative references should be EN, ISO and IEC standards. If EN, ISO and IEC standards do not exist, exceptionally, other standards could be used under certain conditions:

  • the references must comply with IR3 conditions (see CEN-CENELEC Internal Regulations – Part 3, clause 10.2)
  • a TC decision and justification is needed
  • the documents need to be available for the assessment by the HAS Consultant/European Commission.

2.1.5 Requirements

To receive a compliant assessment, the standard must contain objectively verifiable requirements and test methods – as described in the ISO/IEC Directives Part 2 and the CEN-CENELEC Internal Regulations - Part 3: “Expression in the content of a document conveying objectively verifiable criteria to be fulfilled and from which no deviation is permitted”.

If compliance with the document is to be claimed, requirements shall be objectively verifiable. Only those requirements which can be verified shall be included. Phrases such as “sufficiently strong” or “of adequate strength”, etc. shall not be used because they are subjective statements.

2.1.6 EU legal text in the standard

The terminology used in the standard, including definitions of terms in Clause 3, shall be consistent with the relevant EU legislation. The technical content of the document shall not:

  • contain requirements that contradict relevant EU legislation (e.g. fails to specify 'technical solutions', allows users of a document to decide on the specification);
  • repeat legal requirements as part of its normative requirements.

Where a definition differs from relevant EU legislation, the difference shall be indicated in the European Foreword and in Annex Z.

2.1.7 Risk reduction

If a harmonized product standard deals with safety aspects, the relevant hazards must be identified and the risks reduced.

2.1.8 Neutrality principle

The draft standard must respect the neutrality principle (see CEN-CENELEC Internal Regulations – Part 3, clause 33).

The standard shall not contain clauses imposing requirements or obligations on or between certain economic operators (e.g. requirements are set to an economic operator and its competence or resources instead of to product design and product properties).

The standard shall not contain clauses imposing first, second- or third-party conformity assessment.

2.1.9 Annex ZA

The Annex ZA is an informative Annex demonstrating the relationship between the clauses of the harmonized standards and the requirements of the EU legislation aimed to be covered. For the drafting of the informative Annex ZA, the latest template shall be used (see Annex ZA section under Forms & Templates).

The rows shall be placed in order of the legal requirements, which is considered a best practice. If a legal requirement is claimed as covered in the Annex ZA, this requirement shall be clearly addressed by a clause/sub-clause of the standard.

If a standard deals with the aspects which are outside the scope of the EU legislation, clauses/sub-clauses dealing with these aspects shall not be referred to in the informative Annex ZA.

In case the standard covers different EU Directives/Regulations, separate Annexes ZA shall be prepared. 

For drafting guidance related to projects linked to the innovative process see HAS Assessment Process for homegrown ENs.



This section lists available horizontal training material.



This section lists various sectoral guidance documents and training material to support Technical Bodies and WGs in the drafting of harmonized standards supporting EU legislation.




Gas Appliances

  • CEN Guide 18: Gas Appliances and Fittings – Guidelines for the implementation of Essential Requirements of Gas Appliances Regulation 2016/426/EU in European Standards (2021)


Pressure equipment




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