The writing and formatting rules that apply to CEN are based on the ISO/IEC Part 2 guidelines. The principles and rules for the structure and drafting of CEN and CENELEC documents are a modified version of these guidelines, adapted to meet CEN-CENELEC’s requirements for the publication of European standards. This document should therefore be consulted in case of doubt or for further information or examples. To assist with drafting, the ISO Central Secretariat has created a web page supplementing Part 2 on the language, format, and presentation of ISO documents, which can also be used for European standards. Finally, if necessary, CEN has also published various guides to assist experts in drafting standards and using templates (if you do not work with OSD).
All the tables cited in the following parts are from the Principles and rules for the structure and drafting of CEN and CENELEC documents.
Terms and numbering of divisions and subdivisions in a standard
| Terms | Numbering |
| Part | XXX-1 |
| Clause | 1 |
| Subclause | 1.1 |
| Subclause | 1.1.1 |
| Paragraph | N/A |
| Annex | A |
| Annex subclause | A.1 |
| Annex subclause | A.1.1 |
| Annex paragraph | N/A |
Aspect of a summary in a standard
Overview of the major subdivisions of a document and their arrangement in the text
| Major subdivision | Mandatory/Optional/Conditional | Normative/Informative | |
| Title | Mandatory | Normative | |
| Table(s) of content | Optional | Informative | |
| Foreword | Mandatory | Informative | |
| Introduction | Optional/Conditional | Informative | |
| Scope | Mandatory | Normative | |
| Normative references | Mandatory | Informative | |
| Terms and definitions | Mandatory | Normative | |
| Symbols and abbreviated terms | Conditional | Normative | |
| Technical content For example: test methods | Mandatory/Optional/Conditional | Normative or Informative | |
| Annexes | Optional | Normative or Informative | |
| Bibliography | Conditional | Informative | |
| Indices | Optional | Informative | |
| a These may include a list of major subdivisions of the document and lists of figures, tables and similar numbered elements. b The Introduction is an optional element. It is only mandatory if a specific patent right has been identified during the development of the document. c When no normative references or terms are listed, use the introductory texts provided in CEN-CENELEC Internal Regulations Part 3 15.5.1 and 16.5.2. NOTE : Informative elements are used to facilitate the readability of the standard. | |||
Use of requirement in a standard
To express a requirement, use “shall / shall not” :
Example : Connectors shall conform to the electrical characteristics specified by IEC 60603-7-1
In procedures or test methods, you can use the imperative mood :
Examples : Switch on the recorder / Do not activate the mechanism before…
Do not use “must / may not” as an alternative for “shall / shall not”.
You can use equivalent phrases or expressions in certain cases, as “it is required that / is required to be not” etc. If you want to know more, please refer to the “Table 3 – Requirement”.
How to express recommendation in a standard
To express a recommendation, use “should / should not” :
Example : Wiring of these connectors should take into account the wire and cable diameter of the cables defined in the IEC 61156.
You can use equivalent phrases or expressions in certain cases, as “it is recommended that / it is not recommended that” or “ought to / ought not to”.
How to express permission in a standard
To express a permission, use “may” :
Example : IEC 60512-26-100 may be used as an alternative to IEC 60512-27-100 for connecting hardware that has been previously qualified to IEC 60603-7-3:2010.
You can use instead of may : is permitted / is allowed / is permissible
Do not use instead of may : possible / impossible / can / might
“May” signifies a permission expressed by the document, whereas “can” refers to the ability of a user of the document or to a possibility open to him/her.
Negative permissions are ambiguous and should not be used. Rather than using negative permissions, either rewrite the sentence to state what is permitted, or rewrite as a requirement/recommendation not to do something.
How to express possibility and capability in a standard
To express a possibility and capability, use “can / cannot” :
Examples : Only the reverse calculation approach given in Clause E.3 can be used for calculated energy performance / These measurements cannot be used to compare different sprayer setups on the same sprayer.
Do not use instead of can : may
Instead of “can / cannot” you can use “be able to / be unable to”.
If you want to know more, please refer to the “Table 6 — Possibility and capability”.
How to express external constraint
To express an external constraint, use “must” :
Examples : Particular conditions existing in a country – Because Japan is a seismically active country, all buildings must be earthquake-resistant.
A law of nature – All fish must maintain a balance of salt and water in their bodies to stay healthy
Do not use “must” as an alternative for “shall”
How to write a note in a standard
Notes are used for giving additional information intended to assist the understanding or use of the text of document, not requirement or specification. The document shall be usable without the notes.
Example : NOTE This definition is based on the ISO 27001.
For a figure : A single note in a figure shall be preceded by “NOTE”, placed at the beginning of the first line of the text of the note. When several notes occur in the same figure, they shall be designated “NOTE 1”, “NOTE 2”, “NOTE 3”, … The numbering restarts for each new figure. Notes to figures shall not contain requirements or any information considered indispensable for the use of the document. Any requirements relating to the content of a figure shall be given in the text, in a footnote to the figure or as a paragraph between the figure and its title.
For a table : Notes to tables shall be located within the frame of the relevant table and shall precede table footnotes. A single note in a table shall be preceded by “NOTE”, placed at the beginning of the first line of the text of the note. When several notes occur in the same table, they shall be designated “NOTE 1”, “NOTE 2”, “NOTE 3”, … The numbering restarts for each new table. Notes to tables shall not contain requirements or any information considered indispensable for the use of the document. Any requirements relating to the content of a table shall be given in the text, in a footnote to the table or as a paragraph within the table.
If you want to know more, please refer to the “Table 8 — Use of notes, footnotes and notes to entry within documents”.
How to write a footnote in a standard
Footnotes to the text of a document are used to give additional contextual information to a specific item in the text, not requirement or specification. The document shall be usable without the footnotes.
Example : NOTE This standard is still being drafted at the time of publication.
For a figure : Footnotes to figures are numbered independently of footnotes to the text and shall be distinguished by superscript lowercase letters, starting with “a”.
The footnotes shall be referred to in the figure by inserting the same superscript lowercase letter. Footnotes to figures may contain requirements.
For a table : Footnotes to tables are numbered independently from footnotes to the text and shall be located within the frame of the relevant table. They shall appear at the foot of the table. Footnotes to tables shall be distinguished by superscript lowercase letters, starting with “a” and shall be referred to in the table by inserting the same superscript lowercase letter. Footnotes to tables may contain requirements.
If you want to know more, please refer to the “Table 8 — Use of notes, footnotes and notes to entry within documents”.
How to write a title for figures and tables
Use a centered title in the form “Figure/Table X – Title”, X being an Arabic numerals independent of articles. For example an imaginary “Figure/Table 1 – Test requirements” can be in the “4.2 Requirements”. When several tables and/or figures occur in the standard, they shall be nominated “Figure/Table 1 – Title”, “Figure/Table 2 – Title”, “Figure/Table 3 – Title”… Figures and tables have each one their own numbering, they’re never numbering together. For example, a “Figure 2 – Title” cannot exist because there is a “Table 1 – Title”, it only exists because there’s already a “Figure 1 – Title”.
When it’s in an annex, use the reference from the appendix, for example in an annex A it’ll be “Figure/Table A.1 – Recommendation”. When several tables and/or figures occur, they shall be nominated “Figure/Table A.1”, “Figure/Table A.2”, “Figure/Table A.3”. The numbering restarts for each new annex.
Normative references
Normative references may not be standardization documents, but this remains exceptional (TC decision at CEN level). In case of check in advance with the CEN editor whether this document can be used.
References to specific elements of a cited document (e.g., articles, paragraphs, tables, and figures) must always be dated. Undated references imply that the current version of the cited document is being taken into account and this document may have been modified after the standard was published.
References to harmonized standards must always be dated. Normative references in harmonized standards must be dated.
Annex ZA (CEN) / Annex ZZ (CENELEC)
In the context of a harmonized standard, Annex ZA links the requirements of a European Directive or Regulation to the content of the standard. You can find the generic template in the CEN BOSS drafting standards.
Figure 1 : Process Homegrown candidate hEN for citation
Figure 2 : Timeline Homegrown candidate hEN for citation
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