The ISO/IEC Directives, Part 2 has been prepared by the ISO/IEC Joint Directives Maintenance Team (JDMT) and approved by the ISO Technical Management Board (ISO/TMB) and the IEC Standardization Management Board (IEC/SMB).

This ninth edition of the ISO/IEC Directives, Part 2 cancels and replaces the eighth edition published in 2018.

This edition includes the following significant changes compared with the previous edition:

The ISO/IEC Directives, Part 2 states the general principles by which ISO and IEC documents are drafted and stipulates certain rules to be applied in order to ensure that they are clear, precise and unambiguous. These rules are also important for ensuring that each document contributes effectively to the consistent and interdependent body of knowledge that ISO and IEC produce.

It is recognized that the ever-increasing range of subject matter covered by ISO and IEC reflects an increasingly diverse range of users of their documents, both geographical and in terms of the level and type of technical expertise that it can be expected to have. Those drafting ISO and IEC documents should try to be aware of the particular needs of their intended users and to write in a style that is likely to be readily understood. It is particularly important to be conscious of the likelihood that a document will be translated.

Advice on applying the ISO/IEC Directives, Part 2 is readily available from ISO Central Secretariat and IEC Central Office, as appropriate, and it should be sought whenever any difficulties are encountered.

The ISO/IEC Directives, Part 2 contains the principles and rules for the structure and drafting of International Standards, Technical Specifications and Publicly Available Specifications. As far as practicable, these principles and rules also apply to Technical Reports and Guides. All these document types are referred to collectively as “documents”, unless otherwise necessary.

The ISO/IEC Directives, Part 2 does not specify the typography and layout of documents, which are determined by the house style of the publishing organization. Presentation is outside of the scope of the ISO/IEC Directives, Part 2.

The ISO/IEC Directives, Part 2 does not specify the rules governing the process and procedures by which ISO and IEC documents are developed. These rules are provided in the ISO/IEC Directives, Part 1 and ISO, IEC and JTC 1 Supplements.

The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.

ISO 128-3, Technical product documentation (TPD) — General principles of representation — Part 3: Views, sections and cuts

ISO 690, Information and documentation — Guidelines for bibliographic references and citations to information resources

ISO 3098 (all parts), Technical product documentation — Lettering

ISO 5807, Information processing — Documentation symbols and conventions for data, program and system flowcharts, program network charts and system resources charts

For the purposes of this document, the following terms and definitions apply.

ISO and IEC maintain terminology databases for use in standardization at the following addresses:

document

ISO or IEC standardization draft or publication

standard

international standard

International Standard

Technical Specification

TS

Publicly Available Specification

PAS

Guide

Technical Report

TR

normative document

document that provides rules, guidelines or characteristics for activities or their results

[SOURCE: ISO/IEC Guide 2:2004, 3.1, modified — The original Notes to entry have been deleted.]

normative element

informative element

mandatory element

conditional element

optional element

provision

statement

requirement

recommendation

permission

possibility

capability

external constraint

state of the art

profile

named combination of options, chosen according to a specified framework, that are necessary to accomplish a particular function

Note 1 to entry: The options can be chosen from one or several documents or subdivisions of documents.

The objective of documents is to specify clear and unambiguous provisions in order to help international trade and communication. To achieve this objective, documents shall:

• be complete within the limits specified by their scope;

Rules for the planning and preparation of new work items are given in the ISO/IEC Directives, Part 1. The rules given in the ISO/IEC Directives and ISO and IEC Supplements shall be applied throughout all stages of drafting to avoid delay. In order to ensure the timely publication of a document or of a series of associated documents, the following shall be determined before drafting begins:

• the intended structure;

• any interrelationships;

It is not always necessary or possible to standardize all characteristics of an item or a subject. The choice of characteristics to be standardized depends on the aims of the document (e.g. health, safety, protection of the environment, interface, interchangeability, compatibility or interworking, and variety control). A functional analysis of the product can help to identify the characteristics to be included in the document.

The content of a document shall be written so that it can be applied and adopted without change as a regional or national standard. Only characteristics that are suitable for international acceptance shall be chosen. Where necessary, several options may be indicated (e.g. owing to differences in legislation, climate, environment, economies, social conditions, trade patterns).

See ISO/IEC Guide 21-1 for regional or national adoption of International Standards and ISO/IEC Guide 21-2 for regional or national adoption of other International Deliverables.

Whenever possible, requirements shall be expressed in terms of performance rather than design or descriptive characteristics. This principle allows maximum freedom for technical development and reduces the risk of undesirable market impacts (e.g. limiting development of innovative solutions).

When the performance principle is adopted, ensure that features relevant to the scope of the document are not inadvertently omitted from the performance requirements.

If it is impossible to determine the necessary performance characteristics, the material or product may be specified. However, in such a case, the phrase “… or any other material or product proved to be equally suitable” should be included.

Requirements concerning the manufacturing process shall usually be omitted in favour of tests to be carried out on the final product. There are, nevertheless, some fields in which reference to the manufacturing process is necessary (e.g. hot rolling, extrusion) or even in which an inspection of the manufacturing process is necessary (e.g. pressure vessels).

However, it is necessary to consider whether to specify by description or by performance because specification by performance can lead to complicated, costly and lengthy testing procedures.

Requirements shall be objectively verifiable. Only those requirements that can be verified shall be included.

Phrases such as “sufficiently strong” or “of adequate strength” shall not be used because they are subjective statements.

The stability, reliability or lifetime of a product shall not be specified if no test method is known that can verify the claim in a reasonably short time. A guarantee by the manufacturer is not a substitute for such requirements. Guarantee conditions shall not be included because they are commercial or contractual, rather than technical, in nature.

Consistency should be maintained within each document and within a series of associated documents.

• The structure of associated documents and the numbering of their clauses should, as far as possible, be identical.

• Identical wording should be used to express identical provisions.

• The same terminology should be used throughout. The use of synonyms should be avoided.

Consistency is particularly important to help the user understand documents or series of associated documents. It is also important when using automated text processing techniques and computer-aided translation.

Documents should avoid duplication. This is particularly important in test methods, which are often applicable to more than one product, or type of product.

If the aim of a document is standardization of a single size for a product, but there is more than one widely accepted size in international use, a committee may decide to include alternative product sizes in the document. However, in such cases, every effort shall be made to reduce the number of alternatives to a minimum, taking the following points into account:

• the volume of international trade in the sort of product involved shall serve as a criterion for “international use”, not the number of countries or the volume of production in those countries;

• only sizes that are likely to be in international use in the reasonably foreseeable future (e.g. five years or more) shall be included in the document.

Whenever alternative solutions are to be adopted internationally, they shall all be included in the same document and preferences for the different alternatives shall be provided. The reasons for the preferences shall be explained in the Introduction.

When agreed by the committee and approved by the ISO Technical Management Board (ISO/TMB) or the IEC Standardization Management Board (IEC/SMB), a transitional period may be indicated during which the use of non-preferred values is permitted.

In some cases, a document may list characteristics that can be chosen freely by the supplier. The characteristics chosen shall be stated, for example on a nameplate, label or accompanying document.

For most kinds of complex item, it is impractical to specify exhaustive performance requirements. Instead, it is preferable to require that the item be supplied with a list of performance data.

This approach is not acceptable in the case of health and safety requirements.

Documents listing characteristics for which suppliers or purchasers are required to state values or other data not specified by the document shall specify how such values are to be measured and stated.

Documents are so diverse that no universally acceptable rules can be established for the subdivision of the subject matter.

However, as a general principle, an individual document shall be prepared for each subject to be standardized, and published either as a single standard or a single part of a series.

Such subdivision has the advantage that each part can be revised separately as necessary.

In particular, the aspects of a product that are of separate interest to different parties (e.g. manufacturers, certification bodies, legislative bodies or other users) shall be clearly distinguished, preferably as parts of a document or as individual documents.

There are two main ways of subdividing subject matter within a series of parts.

a) Each part deals with a specific aspect of the subject and can stand alone.

b) There are both common and specific aspects to the subject. The common aspects shall be given in Part 1. Specific aspects (which can modify or supplement the common aspects and therefore cannot stand alone) shall be given in separate individual parts.

Where the system described in b) is used, ensure that the references from one part to another are valid. There are two ways of achieving this.

Certain documents contain supplementary material that is best provided in electronic formats, which differs from that of the main content.

This supplementary material can be provided as an attached file or a hyperlink (URN or URL).

Supplementary content shall only be provided in this way if it cannot reasonably be included in the main body of the text.

Each item of supplementary content shall be explicitly referred to within the text in order to explain its context and use.

One of the primary objectives of standardization is to minimize variation and encourage single common standards for worldwide use. However, in some cases, it is necessary to choose sets and subsets of characteristics from a common defined framework for specific applications.

In such cases, the subject matter may be subdivided and organized using profiles.

The number of profiles shall be limited, and profiles defined only when essential to meet technical, regional or application needs.

Profiles shall be specified in accordance with a defined scheme.

The user of the document shall be able to identify the requirements he/she is obliged to satisfy in order to claim conformance to a document. The user shall also be able to distinguish these requirements from other types of provision (recommendations, permissions, possibilities and capabilities).

The general policy on languages is explained in the ISO/IEC Directives, Part 1.

The different language versions of documents shall be technically equivalent and structurally identical.

The use of bilingualism from the initial stage of drafting is of great assistance in the preparation of clear and unambiguous texts.

Documents containing text in languages additional to the official languages shall contain the following text (completed as appropriate) in the Foreword.

Spelling shall be consistent throughout a document. The following reference works for spelling are suggested:

• for English, the Shorter Oxford English Dictionary, the Concise Oxford English Dictionary, the Collins Concise English Dictionary, the Webster’s New World College Dictionary or the Chambers Concise Dictionary;

• for French, Dictionnaire Le Robert, Dictionnaire Larousse and Dictionnaire des difficultés de la langue française (A.V. Thomas, Larousse).

The names of organizations, and their abbreviated forms, shall be written as used by those organizations, in English, French or Russian.

The use of abbreviated terms shall be consistent throughout the document.

To help users understand and use the document correctly, the linguistic style shall be as simple and concise as possible. This is particularly important for those users whose first language is not one of the official languages of ISO and IEC.

Whenever possible, inclusive terminology shall be used to describe technical capabilities and relationships. Insensitive, archaic and non-inclusive terms shall be avoided. For the purposes of this principle, “inclusive terminology” means terminology perceived or likely to be perceived as welcoming by everyone, regardless of their sex, gender, race, colour, religion, etc.

New documents shall be developed using inclusive terminology. As feasible, existing and legacy documents shall be updated to identify and replace non-inclusive terms with alternatives that are more descriptive and tailored to the technical capability or relationship.

Numbers should be written in upright type, irrespective of the type used in the rest of the text.

The decimal sign shall be a comma on the line in all language versions.

If the magnitude (absolute value) of a number less than 1 is written in decimal form, the decimal sign shall be preceded by a zero.

Each group of three digits shall be separated by a small space from the preceding digits, counting from the decimal sign. This also applies to digits following the decimal sign. When there is no decimal sign, the counting shall be from the rightmost digit towards the left. The separation into groups of three digits does not apply to binary and hexadecimal numbers, numbers designating years or the numbering of standards.

When numbers or numerical values have a decimal separator, their multiplication shall be indicated by the multiplication cross (×), instead of a half-high dot.

ISO 80000-2 gives an overview of multiplication symbols for numbers.

Where the document defines, describes, refers to or contains programming language, pseudo-code or mark-up language text, the representation of the numbers, symbols for variable quantities and numerical values shall follow the syntax of the appropriate programming language, pseudo-code or mark-up language.

Quantity symbols should be written in italic type, irrespective of the type used in the rest of the text.

Quantity symbols shall be chosen, wherever possible, from the various parts of the IEC 60027 series, the ISO 80000 series, the IEC 80000 series and ISO Guide 99.

Subscripts for quantity symbols are allowed and are printed in italic type when they represent a quantity or a mathematical variable. They are printed in upright type when they represent a word or a fixed number.

The symbol of the product of two or more quantities is indicated in one of the following ways:

ab, a b, a · b, a × b, a * b

abc, a b c, a · b · c, a × b × c, a * b * c

The multiplication cross (×) may also be used to indicate vector products or cartesian products.

The half-high dot (·) may also be used to indicate a scalar product of vectors and comparable cases, and may also be used to indicate a product of scalars and in compound units.

The division of one quantity by another is indicated in one of the following ways:

, a/b, a b-1, a · b-1

A solidus (/) shall not be followed by a multiplication sign or a division sign on the same line unless parentheses are inserted to avoid any ambiguity:

(a / b) / c = a / (bc), not a / b / c

Names of quantities or multiletter abbreviated terms, for example, presented in italics or with subscripts, shall not be used in the place of symbols.

The International System of units (SI) as set out in the ISO 80000 series and the IEC 80000 series shall be used.

The units in which any values are expressed shall be indicated.

It is not permitted to modify a unit symbol (e.g. by means of a subscript) to give information about the special nature of the quantity or context of measurement.

Language-specific abbreviated terms such as “ppm” should not be used, if possible. If it is necessary to use language-specific abbreviated terms such as “ppm”, their meaning shall be explained.

Mathematical signs and symbols shall be in accordance with ISO 80000-2.

To express values of physical quantities, Arabic numerals (called “numerical values”) followed by the international symbol for the unit shall be used (see the ISO 80000 series, the IEC 80000 series, the IEC 60027 series and ISO/IEC Guide 99).

In the expression of a quantity value, there is always a space between the numerical value and the unit symbol. The only exception to this convention is for plane angles expressed with superscript-type unit symbols. However, the degree should preferably be subdivided decimally. In some fields of science, the usage of the units minute (ʹ) and second (ʺ) is preferred, e.g. for geographic coordinates.

The quantity value is expressed with only one symbol unit, with the exception of sexagesimally divided units like the plane angle (in special fields like astronomy, cartography and navigation) and the time, although the seconds are decimally divided.

To designate a set of values between a and b, where a < b, the symbol [a, b] is used, designated by “interval”. The difference r = b – a, denoted r[a, b], is designated by “the range of the interval [a, b]”.

To indicate that one of the end points is excluded from the interval, the square bracket may be replaced by a parenthesis.

Values and dimensions shall be indicated as either nominal, ordinal, theoretically exact, or including a tolerance.

By the same token, their tolerances (if applicable) shall be specified in an unambiguous manner.

In order to avoid misunderstanding, tolerances on values expressed in per cent shall be expressed in a mathematically correct form.

Any value or dimension that is mentioned for information only shall be clearly distinguishable from requirements.

For some purposes, it is necessary to specify limiting values (maximum, minimum). Usually one limiting value is specified for each characteristic. In the case of several widely used categories or levels, several limiting values are required.

Limiting values of strictly local importance shall not be included in a document.

For some purposes, values or series of values may be selected, particularly for variety control and interface purposes. They may be selected in accordance with the series of preferred numbers given in ISO 3 (see also ISO 17 and ISO 497), or according to some modular system or other determining factors. For the electrotechnical field, recommended systems of dimensional sizes are given in IEC Guide 103.

Documents that have been established to specify selected values for equipment, or components that may be referred to in the provisions of other documents, shall be regarded, in this respect, as basic standards.

Values of strictly local importance shall not be included in a document. In standardizing a rationalized series of values, existing series shall be examined to see whether any would be acceptable for international application.

If a series of preferred numbers is used, difficulties can arise if fractions such as “3,15” are introduced: these can sometimes be inconvenient or require unnecessarily high accuracy. In such cases, they should be rounded in accordance with ISO 497. The specification of different values for use in different countries (whereby both the precise value and the rounded value are contained in the document) shall be avoided.

The entire collection of International Standards published by ISO and IEC is interrelated and forms a system whose integrity has to be preserved.

Therefore, references to particular pieces of text should be used instead of repetition of the original source material. Repetition introduces the risk of error or inconsistency and increases the length of the document. However, if it is considered necessary to repeat such material, its source shall be referenced precisely.

Imprecise references such as “the following clause” or “the figure above” shall not be used.

References can be made

Normatively referenced documents shall be documents published by ISO or IEC. In the absence of appropriate ISO or IEC documents, those published by other bodies may be listed as normative references provided that

a) the referenced document is recognized by the committee as having wide acceptance and authoritative status,

b) the committee has the agreement of the authors or publishers (where known) of the referenced document for its inclusion as a reference,

c) the authors or publishers (where known) have also agreed to inform the committee of their intention to revise the referenced document and what points the revision will affect,

d) the document is available under commercial terms which are fair, reasonable and non-discriminatory, and

e) any patented item required for the implementation of the document is available to be licensed in accordance with the ISO/IEC Directives, Part 1, 2021, 2.14, “Reference to patented items”.

Informative reference may be made to any other type of document. Informative references shall be listed in the Bibliography.

ISO and IEC normatively referenced documents shall have reached at least the enquiry stage (40.20 DIS or CDV).

The committees shall validate all referenced documents when a document is revised.

The normative references list shall not include the following:

• referenced documents which are not publicly available (in this context, “publicly available” means published documents which are available free of charge, or available commercially under fair, reasonable and non-discriminatory terms to any user);

• referenced documents which are cited only informatively as bibliographic or background material.

Documents shall be referred to by their number and, if applicable, date of publication and title.

For other referenced documents and information resources (printed, electronic or otherwise), the relevant rules set out in ISO 690 shall be followed.

For online referenced documents, information sufficient to identify and locate the source shall be provided. Preferably, the primary source of the referenced document should be cited in order to ensure traceability.

The information shall include the method of access to the referenced document and the full network address, with the same punctuation and use of uppercase and lowercase letters as given in the source (see ISO 690).

Furthermore, the referenced document should be expected to remain valid for the expected life of the referring document.

Undated references may be made:

• only to a complete document;

• if it will be possible to use all future changes of the referenced document for the purposes of the referring document;

• when it is understood that the reference will include all amendments to and revisions of the referenced document.

Dated references are references to

• a specific edition, indicated by the date of publication, or

• a specific enquiry or final draft, indicated by a dash.

Normative references to enquiry or final drafts are potentially risky, and are strongly discouraged, as the referenced document can change before publication.

For dated references, each shall be given with its year of publication. In the case of enquiry or final drafts, the date shall be replaced with a dash together with an explanatory footnote (see Example 2).

The date of publication shall be indicated by the year or, for documents for which more than one edition of the document or an element within the document will be published in the same calendar year, the year of publication and the month (and, where necessary, the day).

If the referenced document is amended or revised, the dated references to it shall be reviewed to assess whether they shall be updated or not.

In this context, a part is regarded as a separate document.

Within the text, references to specific elements (e.g. clauses or subclauses, tables and figures) of a referenced document shall always be dated, because these elements are sometimes renumbered in subsequent editions of the referenced document.

In the Normative references clause or the Bibliography, use the following forms to list dated references.

In the text, use the standard identifier rather than the title when referring to an ISO or IEC document. The titles are usually only written out in full in the Normative references clause and in the Bibliography.

In the text, use the following forms to make dated references to a document.

For an individual document, the form “this document” shall be used.

In contexts where it is necessary to specify the number of the document, it is acceptable to do so.

References to particular elements of the text (e.g. clauses, subclauses, tables, figures, mathematical formulae, annexes) are made by using their number.

References shall not be made to page numbers, since pagination can change if the referenced document is published in different formats, or if the document is revised.

If content has been subdivided into a series of parts, reference in the text to the entire series including the individual document shall be made using the form “the ISO xxxx series” or “the IEC xxxx series”.

Such undated references are understood to include all amendments and revisions to the referenced document.

The title is a clear, concise description of the subject matter covered by the document. It is drafted so as to distinguish the subject matter from that of other documents, without going into unnecessary detail. Any necessary additional details are given in the Scope.

The title is a normative element.

The title is a mandatory element.

The title is composed of separate elements, each as short as possible, proceeding from the general to the particular, for example:

a) an introductory element indicating the general field to which the document belongs (this can often be based on the title of the committee which prepared the document);

b) a main element indicating the principal subject treated within that general field;

c) a complementary element indicating the particular aspect of the principal subject or giving details that distinguish the document from other documents, or other parts of the same series.

No more than three elements shall be used. The main element shall always be included.

The title of a part shall be composed in the same way. All the individual titles in a series of parts shall contain the same introductory element (if present) and main element, while the complementary element shall be different in each case in order to distinguish the parts from one another. The complementary element shall be preceded in each case by the designation “Part …:”.

When a document is divided into subparts (in the IEC), the parts within each subseries shall have the same subseries title.

The title shall not contain details that can unintentionally limit the scope of the document.

The terminology used in the titles of documents shall be consistent.

For documents dealing exclusively with terminology, the following expressions shall be used:

• “Vocabulary” if both terms and definitions are included, or

• “List of equivalent terms” if only equivalent terms in different languages are given.

For documents dealing with test methods, use the form

“Test method” or “Determination of …”

instead of expressions such as

“Method of testing”, “Method for the determination of …”, “Test code for the measurement of …” and “Test on …”.

The type or nature of the document (e.g. International Standard, Technical Specification, Publicly Available Specification, Technical Report or Guide) shall not be indicated in the title.

Expressions such as “International test method for …” and “Technical Report on …” shall therefore not be used.

The word “Guide” shall not be used in titles of documents developed by technical committees and subcommittees as it corresponds to a specific document type developed under the authority of the management boards (see the ISO/IEC Directives, Part 1). Titles using the word “Guidance” are acceptable (e.g. “ISO 26000, Guidance on social responsibility”).

The Foreword provides information on:

• the organization responsible for publishing the document;

• the committee that developed the document;

• the procedures and rules under which the document was developed;

• the voting process;

• legal disclaimers;

• relationships between the present document and other documents.

The Foreword is an informative element. It shall not contain requirements, permissions or recommendations.

The Foreword is a mandatory element.

The Foreword shall not have a clause number and shall not be subdivided.

The general part of the Foreword is a fixed text supplied by the Central Secretariat of ISO or by the Central Office of the IEC. It provides information relating to the organization responsible and to documents in general, legal texts as well as the procedures and rules under which the content was developed.

The fixed part of the Foreword is followed by a specific part, supplied by the committee secretariat, and it shall provide as many of the following as are appropriate:

a) the designation and name of the committee that developed the document (working groups and other temporary entities are not referred to in the Foreword);

b) an indication of any other international organization that has contributed to the development of the document;

c) a statement that the document cancels and replaces other documents in whole or in part, and a statement of significant changes with respect to the previous edition of the document;

d) the relationship of the document to other documents;

e) for documents containing text in languages additional to the official languages, the following text completed as appropriate.

The Introduction provides specific information or commentary about the technical content of the document, and about the reasons prompting its preparation.

The Introduction is an informative element. It shall not contain requirements.

The Introduction is an optional element. It is only mandatory if a specific patent right has been identified during the development of the document.

The Introduction shall not have a clause number. If it is necessary to create numbered subdivisions, the subclauses are numbered 0.1, 0.2, … .

Whenever alternative solutions are offered in a document and preferences for the different alternatives provided, the reasons for the preferences shall be explained in the Introduction.

The Scope clearly defines the subject of the document and the aspects covered, thereby indicating the limits of applicability of the document or particular parts of it.

For the purposes of clarity, the Scope can indicate other subjects that are excluded from the document, when other subjects can be implied by the wording of the Scope or title.

In documents that are subdivided into parts, the Scope of each part shall define the subject of that part of the document only.

The Scope shall be succinct so that it can be used as a summary for bibliographic purposes, for example, as an abstract. If further details and background information are necessary, these shall be included in either the Introduction or in an annex.

The Scope is a normative element because it delimits the subject of the document.

The Scope is a mandatory element.

The Scope shall be numbered as Clause 1. It may be subdivided; however, this is not normally necessary as it is meant to be succinct.

The Scope shall not contain requirements, permissions or recommendations.

It shall appear only once in each document and shall be worded as a series of statements of fact.

Forms of expression such as the following shall be used:

     “This document

Statements of applicability of the document shall be introduced by wording such as:

• “This document is applicable to …”

• “This document does not apply to …”

The Normative references clause lists, for information, those documents which are cited in the text in such a way that some or all of their content constitutes requirements of the document.

Information on how these references apply is found in the place where they are cited in the document, and not in the Normative references clause.

The Normative references clause is an informative element.

The Normative references clause is a mandatory element, even if it contains no normative references.

The Normative references clause shall be numbered as Clause 2. It shall not be subdivided.

Referenced documents listed are not numbered.

The Normative references clause shall appear only once in each document.

The list of normative references shall be introduced by the following wording:

The above wording is also applicable to a part of a multipart series.

If no references exist, include the following sentence below the clause title:

Only references cited in the text in such a way that some or all of their content constitutes requirements of the document shall be listed in the Normative references clause.

The Terms and definitions clause provides definitions necessary for the understanding of certain terms used in the document.

If necessary, terminological entries can be supplemented by information (including requirements) given in the notes to entry.

Terminology may take the form of an independent terminology standard (a vocabulary, nomenclature, or list of equivalent terms in different languages) or be included in a Terms and definitions clause in a document that also deals with other aspects.

In order to avoid the unnecessary proliferation of terminological variants, it is recommended to use existing terminological entries from International Standards. Search for suitable terms existing in the terminology databases of ISO and IEC:

The Terms and definitions clause is a normative element. It defines the way in which the listed terms shall be interpreted.

The Terms and definitions clause is a mandatory element, even if it contains no terminological entries.

The Terms and definitions clause shall be numbered as Clause 3. It may be subdivided. Terminological entries shall be numbered. The numbering and structure shall be identical in all language versions.

NOTE These numbers are not considered as subclause numbers.

Terms and definitions should be listed according to the hierarchy of the concepts (i.e. systematic order). Alphabetical order is the least preferred order.

For convenience, the symbols and abbreviated terms may be combined with the terms and definitions in order to bring together terms and their definitions, symbols and abbreviated terms under an appropriate composite title, for example “Terms, definitions, symbols and abbreviated terms”.

The Terms and definitions clause shall appear only once in each document.

If all the specific terms and definitions are provided in Clause 3, use the following introductory text:

If reference is given to an external document, use the following introductory text:

If terms and definitions are provided in Clause 3, in addition to a reference to an external document, use the following introductory text:

If there are no terms and definitions provided, use the following introductory text:

Only terms which are used in the document shall be listed in the Terms and definitions clause. This rule does not apply to terminology standards, whose terms are intended for wider use. Within a terminological entry, cross-references may also be made to other terminological entries.

Common terms, which a qualified user of the document will already know, should not be defined.

Types of term:

— Preferred terms are the primary terms for a given concept. The preferred term is the form which is used throughout the main body of the text. If there is more than one preferred term, only one of the preferred terms shall be used except in the case where both a full form and an abbreviated form are preferred terms (in which case they may be used interchangeably). Preferred terms are written in bold type (with the exception of symbols, which shall be presented as used in running text).

— Admitted terms are accepted synonyms for the preferred term. They are written in regular type.

— Deprecated terms are synonyms of the preferred term, which are no longer in use or whose use is discouraged. They are written in regular type.

There can be more than one term of each type. An abbreviated term or a symbol can constitute a term.

Terms shall be written in lowercase letters. Uppercase letters, mathematical symbols, typographical signs, and syntactic signs (e.g. punctuation marks, hyphens, parentheses, square brackets and other connectors or delimiters) as well as their character styles (fonts and bold, italic, bold italic, or other style conventions) shall be used in a term only if they constitute part of the normal written form of the term. Terms shall in general be presented in their basic grammatical form (nouns in the singular, verbs in the infinitive).

The definition shall be written in such a form that it can replace the term in its context. It shall not start with an article (“the”, “a”) nor end with a full stop. A definition shall not take the form of, or contain, a requirement.

Only one definition per terminological entry is allowed. If a term is used to define more than one concept, a separate terminological entry shall be created for each concept and the domain shall be included in angle brackets before the definition.

Circular definitions, which repeat the term being defined, are not allowed.

Examples provide information that illustrates the concept. Examples shall not contain requirements (use of “shall”) or any information considered indispensable for the use of the document, for example instructions (imperative mood), recommendations (use of “should”) or permission (use of “may”). Examples should be written as a statement of fact.

Examples to terminological entries are designated “EXAMPLE” and shall be numbered starting with “1” within each terminological entry. A single example in a terminological entry shall not be numbered.

Figures and formulae may be included within a terminological entry. The definition may take the form of a formula. Refer to ISO 10241-1.

If a terminological entry is reproduced from another document, the source shall be given at the end of the entry. If any changes are made to the original terminological entry, this shall be indicated, along with a description of what has been modified. A document given as a source of a terminological entry is informative.

Footnotes to any part of a terminological entry are not allowed.

Other data categories may be included in a terminological entry, for example:

— country codes;

— grammatical information;

— pronunciation.

Refer to ISO 10241-1 for the general requirements and examples.

The symbols and abbreviated terms clause or subclause provides a list of the symbols and abbreviated terms used in the document, along with their definitions.

The symbols and abbreviated terms clause is a normative element.

The symbols and abbreviated terms clause is a conditional element.

It is not necessary to number the symbols. For convenience, the symbols and abbreviated terms may be combined with the terms and definitions in order to bring together terms and their definitions, symbols and abbreviated terms under an appropriate composite title, for example “Terms, definitions, symbols and abbreviated terms”.

Only symbols used in the text shall be listed.

Unless it is necessary to list symbols in a specific order to reflect technical criteria, all symbols should be listed in alphabetical order in the following sequence:

• uppercase Latin letter followed by lowercase Latin letter (A, a, B, b, …);

• letters without indices preceding letters with indices, and with letter indices preceding numerical ones (B, b, C, Cm, C2, c, d, dext, dint, d1, …);

• Latin letters followed by Greek letters (a, b, … α, β, …);

• any other special symbols.

Measurement and test methods specify the procedure for determining the values of characteristics or for checking conformity to stated requirements. Using a standardized test method ensures comparability of the results.

The measurement and test methods clause is a normative element.

The measurement and test methods clause is a conditional element.

Measurement and test methods may be subdivided in the following order (where appropriate):

a) principle;

If appropriate, tests shall be identified as, for example, type tests, performance tests, sampling tests, routine tests.

The document shall specify the sequence of testing if the sequence can influence the results.

Requirements, sampling and test methods are interrelated elements of product standardization and should be considered together even though the different elements may appear in separate clauses in a document, or in separate documents.

When a specific sampling method is necessary, this shall be clearly stated in the test method.

When drafting test methods, it is important to take into account documents for general test methods and related tests for similar characteristics in other documents.

Non-destructive test methods shall be chosen whenever they can replace, within the same level of confidence, destructive test methods.

Test methods should conform to the metrological principles concerning validation, measurement traceability and estimation of measurement uncertainty described in ISO/IEC 17025:2017, 7.2, 7.6 and 7.7. Other documents may be applicable: ISO/IEC Guide 98-3 (GUM:1995) and ISO/IEC Guide 99 (VIM). Requirements related to testing equipment should conform to the provisions concerning accuracy and calibration specified in ISO/IEC 17025:2017, 6.4.

For guidance on the drafting of methods of chemical analysis, see ISO 78-2. Much of ISO 78-2 is also applicable to test methods for products other than chemical products.

Documents specifying test methods involving the use of hazardous products, apparatus or processes shall include a general warning and appropriate specific warnings. For recommended wording, see ISO/IEC Guide 51. For guidance on the appropriate location of such warnings, see ISO 78-2.

A document which specifies test methods shall not imply any obligation to perform any kind of test. It shall merely state the method by which the test, if required and referred to (e.g. in the same or another document, in a regulation, or in contracts), is to be performed.

If a statistical method for the assessment of the conformity of a product, process or service is specified in the document, any statements of conformance with the document relate only to the conformity of the population or the lot.

If it is specified in the document that every single item is to be tested in accordance with the document, any statements concerning the conformity of the product to the document mean that every single item has been tested and that each has fulfilled the corresponding requirements.

If there are test methods in use that differ from those most acceptable for general application, this shall not be a reason for not specifying the most acceptable test method in a document.

In order to facilitate cross-referencing, individual reagents, materials and apparatus shall be numbered, even if there is only one.

In the associated text where the procedure is given, a cross-reference to the listed item may be provided.

The title shall be “Reagents” or “Materials” or “Reagents and materials”, as appropriate.

It is a conditional element giving a list of any reagents and materials used.

The content of a reagents and materials clause usually comprises an optional introductory text together with a list detailing one or more reagents and materials.

The introductory text shall be used only to specify general provisions to which cross-reference is not made. Any item that can be cross-referenced shall not be included in this text but shall be listed as a distinct entry as shown in the example below.

If more than one adequate test method exists for a characteristic, only one should in principle be specified. If, for any reason, more than one test method is to be specified, a referee test method (often called reference test method) may be identified in the document to resolve doubts or dispute.

When choosing a test method, consider the accuracy of the method relative to the required value and tolerance of the characteristic being assessed.

The chosen test method shall provide an unambiguous determination of whether the sample meets the specified requirement.

When it is technically necessary, each test method shall incorporate a statement as to its limit of accuracy.

If, in preparing a document related to a product, it is necessary to standardize some kind of testing equipment that is likely to be used for testing other products as well, it shall be dealt with in a separate document, prepared in consultation with the committee dealing with such equipment.

This clause specifies which information is to be included in the test report. The clause shall require information to be given on at least the following aspects of the test:

• the sample;

• the International Standard used (including its year of publication);

• the method used (if the standard includes several);

• the result(s), including a reference to the clause which explains how the results were calculated;

• any deviations from the procedure;

• any unusual features observed;

• the date of the test.

Marking, labelling and packaging are important aspects related to product manufacturing and procurement that frequently require a standardized approach, particularly in safety-critical applications.

Marking, labelling and packaging clauses are usually normative elements although exceptions can exist (e.g. when only recommendations are made concerning marking, labelling and packaging).

Marking, labelling and packaging clauses are conditional elements.

Marking, labelling and packaging are complementary aspects that shall be included wherever relevant, particularly for product standards concerning consumer goods.

If necessary, the means of marking shall also be specified or recommended.

This element shall not specify or recommend marks of conformity. Such marks are normally applied under the rules of a certification system – see ISO/IEC Guide 23. Information on the marking of products with reference to a standards body or its documents is given in ISO/IEC 17050-1 and ISO/IEC 17050-2.

Information on safety standards and aspects related to safety is given in ISO/IEC Guide 51.

This element may be supplemented by an informative annex giving an example of information necessary for the purposes of procurement.

Documents containing a reference to the marking of the product shall specify the following, where applicable:

a) the content of any marking that is used to identify the product, for example:

1) the manufacturer (name and address);

2) responsible supplier (trade name, trademark or identification mark);

Documents may require that the product be accompanied by some kind of documentation (e.g. test report, handling instructions, other information appearing in the product packaging). When relevant, the content of such documentation shall be specified.

NOTE A classification and designation system of such documentation for plants, systems and equipment is provided in IEC 61355-1. Rules for such documentation in administration, commerce and industry can be found under the ICS classification 01.140.30.

In product standards, it is sometimes necessary to specify that the product shall be accompanied by warning notices or by instructions to the installer or user, and to specify their nature. Such requirements concerning installation or use may be included in a separate part of the series or a separate document, because they are not requirements applicable to the product.

Annexes are used to provide additional information to the main body of the document and are developed for several reasons, for example:

• when the information or table is very long and including it in the main body of the document would distract the user;

• to set apart special types of information (e.g. software, example forms, results of interlaboratory tests, alternative test methods, tables, lists, data);

• to present information regarding a particular application of the document.

Annexes can be normative or informative elements.

Normative annexes provide additional normative text to the main body of the document.

Informative annexes provide additional information intended to assist the understanding or use of the document. Informative annexes may contain optional requirements. For example, a test method that is optional may contain requirements but it is not necessary to follow these requirements to claim conformance with the document. The status of the annex (informative or normative) shall be made clear by the way in which it is referred to in the text and shall be stated under the heading of the annex.

Annexes are optional elements.

Each annex shall be designated by a heading comprising the word “Annex” followed by a capital letter, starting with “A”, for example “Annex A”. The annex heading shall be followed by the indication “(normative)” or “(informative)”, and by the title.

Annexes may be subdivided into clauses, subclauses, paragraphs and lists.

Numbers given to the clauses, subclauses, tables, figures and mathematical formulae of an annex shall be preceded by the letter designating that annex followed by a full stop. The numbering shall start afresh with each annex.

Each annex shall be explicitly referred to within the text.

The Bibliography lists, for information, those documents which are cited informatively in the document, as well as other information resources.

The Bibliography is an informative element. It shall not contain requirements, permissions or recommendations.

The Bibliography is a conditional element. Its inclusion is dependent on whether informative references are present in the document.

The Bibliography shall not have a clause number. It may be subdivided in order to group the referenced documents under descriptive headings. Such headings shall not be numbered.

Referenced documents and information resources listed may be numbered to simplify cross-referencing.

The Bibliography, if present, shall appear after the last annex.

Clauses and subclauses serve as the basic components in the subdivision of the content of a document.

Each clause shall have a title.

A subclause is a numbered subdivision of a clause. A clause may be subdivided into subclauses as far as the fifth level (e.g. 5.1.1.1.1, 5.1.1.1.2).

Too many levels of subdivision should be avoided, as this can make it hard for the user to understand the document.

A subclause shall not be created unless there is at least one further subclause at the same level. For example, text in Clause 10 shall not be designated subclause “10.1” unless there is also a subclause “10.2”.

“Hanging paragraphs” shall be avoided since reference to them is ambiguous.

Use, for example, the following forms for references to clauses and subclauses:

• “in accordance with Clause 4”;

• “details as given in 4.1.1”;

• “the requirements given in Clause B.2”;

• “the methods described in 5.3 provide further information on...”.

A list serves to subdivide information to aid understanding.

Lists do not have a title. They may, however, be preceded by a title or introductory phrase.

Lists can be numbered or unnumbered. Lists can be subdivided.

See the examples below.

The purpose of a list should be made clear by its context. For example, an introductory proposition or a subclause title can serve to introduce the list.

If cross-references to list items are necessary, a numbered list shall be used. Within a subdivision, each list item in a numbered list shall have a unique identifier. Numbering restarts at each new clause or subclause.

Use, for example, the following forms for references to lists:

• “as specified in 3.1 b)”;

• “the requirements given in Clause B.2 c)”.

Notes are used for giving additional information intended to assist the understanding or use of the text of the document. The document shall be usable without the notes.

Notes do not have a title.

Within a given clause or subclause, notes shall be numbered sequentially. The numbering restarts at each new subdivision. A single note in a subdivision shall not be numbered.

When notes are referred to, use, for example, the following forms for references:

• “an explanation is provided in 7.1, Note 2”;

• “see 8.6, Note 3”.

Examples illustrate concepts presented in the document. The document shall be usable without the examples.

Within a given clause or subclause, examples shall be numbered sequentially. The numbering restarts at each new subdivision. A single example in a subdivision shall not be numbered.

When examples are referred to, use for example, the following forms for references:

• “see 6.6.3, Example 5”;

• “Clause 4, Example 2 lists …”.

Footnotes to the text of a document are used to give additional contextual information to a specific item in the text. The document shall be usable without the footnotes.

Footnotes do not have a title.

Footnotes shall be numbered sequentially throughout the document. Normally, footnote references are indicated using Arabic numerals. Exceptionally, other systems (a, b, c, … ; *, **, ***, … ; †, ‡, …) can be used, for example when there is the possibility of confusing them with superscript numbers.

Footnotes shall be referenced in the text.

Use, for example, the following form for references to footnotes:

ISO 1234:—1 lists the test methods for…

-------------

1   Under preparation. Stage at the time of publication: ISO/DIS 1234:2014.

A footnote can appear anywhere within the text of a document apart from terminological entries.

A mathematical formula uses symbols to express the relationship between quantities.

NOTE Notations such as

      , and , or V/(km/h), l/m and t/s

for numerical values are not mathematical formulae.

Mathematical formulae do not have a title.

Mathematical formulae can be numbered in a document, for example for cross-referencing purposes. Arabic numbers in parentheses shall be used, starting with 1.

By default, the numbering shall be continuous and independent of the numbering of clauses, tables and figures. However, mathematical formulae may be numbered with a prefix and a number, where the prefix denotes the clause number, and the second number denotes the sequence of the formulae in the clause. The numbering system chosen shall be consistent within any given series. Subdivision of mathematical formulae [e.g. (2a), (2b), ...] is not permitted.

When mathematical formulae in annexes are numbered, the numbering restarts and is preceded by the annex letter.

If a mathematical formula is numbered, it should be referred to in the text and its purpose should be made clear by its context, for example, with an introductory proposition.

Use, for example, the following forms for references to mathematical formulae:

• “see 10.1, Formula (3)”;

• “see Clause A.2, Formula (A.5)”.

Mathematical formulae shall be expressed in mathematically correct form.

It is better to use mathematical formulae with quantities than mathematical formulae with numerical values.

If a mathematical formula between numerical values is used, the style shown in Example 2 shall be followed, with explicit reference to the measurement units.

Variables shall be represented by italicized letter symbols. These shall be single-letter symbols except for exceptional cases such as characteristic numbers, which may be multiletter symbols.

The meanings of the symbols shall be explained in connection with the mathematical formulae, unless they appear in a symbols and abbreviated terms clause.

The same symbol shall not be used within a document both for a quantity and for its corresponding numerical value.

Descriptive terms or names of quantities shall not be arranged in the form of a mathematical formula. Names of quantities or multiletter abbreviated terms, for example presented in italics or with subscripts, shall not be used in the place of symbols.

The same symbol should not be used to represent different quantities within the same document. Subscripts can be useful to distinguish symbols for related concepts.

Unit symbols shall not be used within mathematical formulae.

Figures are a graphical means of representation used when they are the most efficient means of presenting information in an easily comprehensible form.

Photographs and other media may be used if it is not possible to represent the concept as a line drawing.

It is recommended to provide a concise figure title.

Figures shall be designated “Figure” and numbered. By default, figures are numbered with Arabic numerals, beginning with 1, and the numbering shall be continuous and independent of the numbering of the clauses and of any tables. A single figure shall be designated “Figure 1”. However, figures may be numbered with a prefix, where the prefix denotes the clause number, and the second number denotes the sequence of figures in the clause. The numbering system chosen shall be consistent within any given series.

In annexes, the figure numbering restarts and the number is preceded by the annex letter (e.g. Figure A.1, Figure A.2, …).

When a figure is continued over several pages, it can be useful to repeat the figure designation, followed by the title (optional) and by “(1 of #)”, where # is the total number of pages on which the figure appears.

In general, the use of subfigures should be avoided whenever possible since it complicates document layout and management.

Only one level of subdivision of a figure is permitted. Subfigures shall be identified by a lowercase letter [e.g. Figure 1 may comprise subfigures a), b), c), ...]. Other forms of identification of the subfigures such as 1.1, 1.2, ... and 1-1, 1-2, ... shall not be used.

Separate keys, notes and footnotes for subfigures are not permitted.

Each figure shall be explicitly referred to within the text.

Use, for example, the following forms for references to figures and subfigures:

• “Figure 3 illustrates…”;

• “See Figure 6 b)”.

Letter symbols used in figures to represent general cases of angular or linear quantities shall be in accordance with ISO 80000-3. Subscripts can be used where necessary to distinguish between different applications of a given symbol.

Various lengths, l, on a drawing should be written with descriptor indices, for example l1, l2, l3, rather than A, B, C, … or a, b, c, … .

Lettering on technical product documentation shall be in accordance with the ISO 3098 series. Italic letters shall be used for symbols for variable quantities.

The vertical (upright) style shall be used for all other lettering.

When all units for a quantity are the same, a suitable statement (e.g. “Dimensions in millimetres”) shall be placed above the right-hand corner of the figure.

Footnotes to figures are numbered independently from footnotes to the text.

Graphical symbols for use on equipment shall be in accordance with IEC 60417 and ISO 7000. Public information symbols shall be in accordance with ISO 7001. Safety signs shall be in accordance with ISO 7010.

For purposes of consistency and coherence, IEC TC 3, IEC SC 3C and ISO/TC 145 are responsible for the standardization of graphical symbols and safety signs. If an adequate symbol or safety sign does not exist in the IEC and ISO databases, contact IEC TC 3, IEC SC 3C and ISO/TC 145 in order to register a standardized symbol.

Graphical symbols for use on technical product documentation (drawings and diagrams) shall be in accordance with ISO 7083 and the ISO 14617 series.

For purposes of consistency and coherence, ISO/TC 10 is responsible for the standardization of graphical symbols for use in technical product documentation. If an adequate symbol does not exist in the IEC and ISO databases, contact ISO/TC 10 in order to register a standardized symbol.

Tables are used when they are the most efficient means of presenting information in an easily comprehensible form.

It is recommended to provide a concise table title.

Tables shall be designated “Table” and numbered. By default, tables are numbered with Arabic numerals, beginning with 1, and the numbering shall be continuous and independent of the numbering of the clauses and of any figures. A single table shall be designated “Table 1”. However, tables may be numbered with a prefix where the prefix denotes the clause number, and the second number denotes the sequence of tables in the clause. The numbering system chosen shall be consistent within any given series.

Further subdivision [e.g. Table 1 a)] is not permitted. A table within a table is not permitted. Subdivision of a table into subsidiary sections with new column headings is not permitted.

It is often better to create several tables rather than trying to consolidate too much information into one table. The simpler the presentation, the better. Complex graphical representations within tables should be avoided.

If a very complex table is necessary, it can be better to include it as a software supplement to the document.

In annexes, the table numbering restarts and the number is preceded by the annex letter (e.g. Table A.1).

When a table is continued over several pages, it can be useful to indicate the continuation.

The column headings together with any statement concerning units can be repeated on all pages after the first.

Each table shall be explicitly referred to within the text.

Use, for example, the following forms for references to tables:

• “Table 3 lists…”;

• “See Table B.1”.

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.

Footnotes to tables are numbered independently from footnotes to the text. They shall be located within the frame of the relevant table and shall appear at the foot of the table.

Footnotes to tables shall be distinguished by superscript lowercase letters, starting with “a”. The footnotes shall be referred to in the table by inserting the same superscript lowercase letter.

Footnotes to tables may contain requirements.

When tables display numerical values of quantity values, notations such as

     , and , or V/(km/h), l/m and t/s

For patented items, the rules given in ISO/IEC Directives, Part 1, shall be followed.

A correct designation or description of a product shall be given rather than a trade name or trademark.

Proprietary trade names or trademarks for a particular product should as far as possible be avoided, even if they are in common use.

If, exceptionally, trade names or trademarks cannot be avoided, their nature shall be indicated, for example by the symbol ® for a registered trademark (see Example 1) and by the symbol TM for a trademark.

If it is known that only one product is currently available that is suitable for the successful application of the document, the trade name or trademark of the product may be given in the text of the document but shall be associated with a footnote as shown in Example 2.

If it is considered essential to give an example (or examples) of commercially available products suitable for successful application of the document because the product characteristics are difficult to describe in detail, trade names or trademarks may be given in a footnote as shown in Example 3.

If it is considered essential for reasons of public interest or public safety to refer to commercially available products, trade names or trademarks may be provided, with a footnote as shown in Example 4.

Copyright in standards is governed by ISO/IEC Directives, Part 1. More information about the copyright policies in ISO and IEC can be found here:

All documents containing requirements for products, processes, services, persons, systems and bodies shall be written in accordance with the “neutrality principle”, such that conformity can be assessed by a manufacturer or supplier (first party), a user or purchaser (second party), or an independent body (third party).

NOTE 1 First-party, second-party and third-party conformity assessment activities are defined in ISO/IEC 17000.

Committees shall not develop documents providing general requirements for conformity assessment schemes and systems. Development of such documents is the responsibility of the ISO policy committee ISO/CASCO in liaison with the IEC Conformity Assessment Board (IEC/CAB).

Committees wishing

a) to propose the establishment of a conformity assessment scheme or system, or

b) to prepare documents specifying conformity assessment systems or schemes or sector-specific operating procedures for use by conformity assessment bodies and others for conformity assessment purposes,

shall consult with the secretariat of ISO/CASCO or IEC/CAB or both as appropriate, prior to commencement of the work to ensure that any documents developed are in line with the conformity assessment policies and rules approved by ISO/CASCO and IEC/CAB as relevant.

When a committee develops a document relating to conformity assessment systems or schemes, or any other document addressing conformity assessment aspects, the document shall make normative reference to the relevant published ISO/IEC documents for conformity assessment procedures, including ISO/IEC 17000 and ISO/IEC 17025. The committee may include verbatim text from the ISO/IEC documents for conformity assessment procedures but the committee shall not delete, change or interpret them. Committees shall consult with the ISO/CASCO or the IEC/CAB secretary or both, as appropriate, for advice on correctly referencing the ISO/IEC conformity assessment documents. Any request for addition, deletion, change or interpretation shall be submitted to the secretariats of ISO/CASCO and IEC/CAB for decision.

General aspects are dealt with by ISO/TC 69 Applications of statistical methods, ISO/TC 176 Quality management and quality assurance and IEC TC 56 Dependability. Documents developed by those technical committees shall be consulted for guidance.

Rules for the drafting of management standards and management systems standards (including sector-specific standards) are given in Annex SL and Annex SP of the ISO Supplement to the ISO/IEC Directives, Part 1.

For the purpose of this annex, an “internationally standardized item” means either a tangible item (e.g. a material or a manufactured product), or an intangible item (e.g. a process or system, a test method, a collection of symbols, or requirements for marking and delivery).

There are many circumstances when it is convenient to have a brief designation to identify the item instead of a lengthy description. These include references given to items in documents, in catalogues, in written communications, in technical and scientific literature, in the ordering of goods, materials and equipment and in the presentation of goods on display and for sale.

The designation system given in this annex shall be used to give items a unique designation. This designation provides a rapid and unambiguous description of the item. The system is intended solely for application in International Standards, and in regional and national standards identical in content with them. It supports international comprehension about items which meet the requirements of the relevant International Standard.

NOTE The designation is no substitute for the full content of the document.

A designation system is particularly useful for product and material documents, but is not always necessary. The committee may choose whether to include a designation system.

a) A document in which more than one choice is open in relation to a characteristic defined in the document.

b) A document which defines terms and symbols from which a selection has to be made to communicate information.

c) For a product or material, a document which contains alternatives in one or more of its requirements, and which provides a specification complete enough to ensure that the product or material conforming to it is of sufficient quality for its intended use.

NOTE There would be considerable risk of misunderstanding by the purchaser if a designation system were applied to a specification that incompletely defined the suitability of a product for its purpose. The designation system is intended to make known only the “selection” aspects in a document, so users would assume that the other characteristics required to ensure suitability of purpose were covered by the document.

The committee shall allot a description block to the standardized item. This description block shall be as short as possible and is preferably taken from the subject classification of the document (e.g. keywords, International Classification for Standards). The description should be that which best characterizes the standardized item. When referring to the document, the use of the description block is optional. When used, it shall be placed in front of the International Standard number block.

The identity block shall be composed in such a way that it designates the standardized item unambiguously. It consists of two consecutive blocks of characters:

• the International Standard number block, comprising a maximum of 8 characters (the letters “ISO” or “IEC” plus a maximum of 5 digits);

• the individual item block (digits, letters, signs), comprising a recommended maximum of 18 characters.

In order to mark the division between the International Standard number block and the individual item block, a hyphen (-) shall be the first character of the individual item block.