ISO 14617-1:2025

International
Standard
ISO 14617-1
Third edition
Graphical symbols for diagrams —
2025-03
Part 1:
General rules
Symboles graphiques pour schémas —
Partie 1: Informations générales et index
Reference number
© ISO 2025
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ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Graphical symbols . 2
4.1 General .2
4.2 Graphical symbols of same shape but different meaning .2
4.3 Dimensions and lines .3
4.4 Modification of proportions .3
4.5 Orientation of graphical symbols .3
4.6 Different forms of graphical symbols .3
4.7 Creation of new symbol examples . .4
4.8 Letter codes, abbreviations, etc. .4
4.8.1 Overview .4
4.8.2 Chemical formulae .4
4.8.3 Unit designations .4
5 Representation of graphical symbols . 4
5.1 Structuring of representation .4
5.2 Representation of graphical symbols in ISO 14617-2 .5
Annex A (informative) Registration numbers for graphical symbols . 6
Annex B (informative) Creation of new symbols . 7
Annex C (informative) Letter codes for process variables, control functions and modifying
purposes . 8
Bibliography .10

iii
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
ISO technical committees. Each member body interested in a subject for which a technical committee
has been established has the right to be represented on that committee. International organizations,
governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely
with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types
of ISO document should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 10, Technical product documentation,
Subcommittee SC 10, Process plant documentation.
This third edition cancels and replaces the second edition (ISO 14617-1:2005), which has been technically
revised.
The main changes are as follows:
— Clause 3 terms and definitions were changed;
— ”GSD” was added in front of registration numbers;
— symbols using letter codes are not included in the revised ISO 14617 series because the definition of
letter codes moved to ISO 15519-2;
— structuring of the presentation of graphical symbols has been changed in order to improve the user’s
access to navigate and find symbols;
— annexes have been reconstructed.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.

iv
Introduction
0.1  General
ISO/TC 10 prepares standards for diagrams including graphical symbols, which together with International
Standards prepared by other ISO committees and the IEC constitute the basis for the preparation of
diagrams.
The interrelations between these International Standards are illustrated in Figure 1. Standards in bold are
ISO/TC 10 standards.
Key
a
Collective application standards.
Figure 1 — Interrelations between ISO and IEC standards for diagrams
0.2  Collective application standards
Technical committees, requiring a field specific standard, can, in co-operation with ISO/TC 10, develop
their own collective application standard for the preparation of diagrams and graphical symbols as per
the requirements given in ISO 15519-1 or ISO 14617, or both. Collective application standards are not to be
contradictory with respect to the source standard(s).

v
International Standard ISO 14617-1:2025(en)
Graphical symbols for diagrams —
Part 1:
General rules
1 Scope
This document specifies general rules for and gives guidance on the preparation and presentation of graphical
symbols for diagrams, which are related to physical industrial components, products and processing.
2 Normative references
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 81714-1, Design of graphical symbols for use in the technical documentation of products — Part 1: Basic rules
3 Terms and definitions
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:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
graphical symbol
visually perceptible figure with a particular meaning used to transmit information independently of
language
Note 1 to entry: The graphical symbol can represent objects of interest, such as products, functions or requirements
for manufacturing, quality control, etc.
Note 2 to entry: A graphical symbol is not to be confused with the simplified representation of products which are
normally drawn to scale and which can look like a graphical symbol.
Note 3 to entry: The graphical symbol means the same as the technical product documentation symbol (TPD-symbol).
[SOURCE: ISO 81714-1:2010, 3.1, modified — Note 3 to entry has been added.]
3.2
basic symbol
symbol which can be used direct in diagrams or combined with supplementary symbols (3.3) to form symbol
examples (3.5)
3.3
supplementary symbol
symbol which can be combined with a basic symbol (3.2) to form a symbol example (3.5)

3.4
application rule
information on how to design composite symbols and how to apply the graphical symbols (3.1) in a diagram
Note 1 to entry: The symbol examples (3.5) are regarded as guidelines.
Note 2 to entry: Application rules for symbols are specified in Annex A of ISO 14617-2:2025.
3.5
symbol example
example of how to combine basis symbols (3.2) and supplementary symbols (3.3) using the application rules (3.4)
Note 1 to entry: Each symbol example is accompanied by information on which basic (3.2) and supplementary symbols
(3.3) have been used to compose itself.
Note 2 to entry: The symbol examples are regarded as guidelines.
Note 3 to entry: Symbol example was denoted as application example in the previous edition of the ISO 14617 series.
3.6
registration number
unique number assigned each graphical symbol (3.1)
Note 1 to entry: In principle, this number is arbitrarily chosen. No information can be derived from it.
Note 2 to entry: The registration number remains unchanged throughout the lifetime of the corresponding graphical
symbol, including in future revisions of this document. If a graphical symbol is slightly changed in the future, the
registration number shall be supplemented with one or more characters. If the graphical symbol is substantially
changed, it shall instead be given a new registration number.
Note 3 to entry: Three types of registration number are used, where "n" is a digit:
— basic and supplementary symbols: GSD nnnn;
— application rules: Rnnnn;
— symbol examples: GSD Xnnnn.
The supplemented registration number according to a small change of symbol is nnnn-m, where “m” is the number of
changing times. Detail explanations of registration number are shown in Annex A.
Note 4 to entry: Annex C specifies common registration number rules for ISO 14617-2 and derived collective application
standards.
Note 5 to entry: ”GSD” was added in front of registration numbers defined in the previous edition of the ISO 14617
series. The reason is to distinguish the graphical symbols in the ISO 14617 series from those defined by other
standards on the ISO Online browsing platform. “GSD” stands for graphical symbols for diagrams.
4 Graphical symbols
4.1 General
Graphical symbols for diagrams shall be designed according to the rules given in ISO 81714-1. For CAx
application, IEC 81714-2 should be applied.
The application of graphical symbols in diagrams for the process industry is described in the ISO 15519 series.
4.2 Graphical symbols of same shape but different meaning
Graphical symbols with the same shape but different meanings have different re
...