SIST EN ISO 5459:2024
(Main)Geometrical product specifications (GPS) - Geometrical tolerancing - Datums and datum systems (ISO 5459:2024)
Geometrical product specifications (GPS) - Geometrical tolerancing - Datums and datum systems (ISO 5459:2024)
This document specifies terminology, rules and methodology for the indication and understanding of datums and datum systems in technical product documentation. This document also provides explanations to assist the user in understanding the concepts involved.
This document defines the specification operator (see ISO 17450-2) used to establish a datum or datum system. The verification operator (see ISO 17450-2) can take different forms (physically or mathematically) and is not the subject of this document.
NOTE The detailed rules for maximum and least material requirements for datums are given in ISO 2692.
Geometrische Produktspezifikation (GPS) - Geometrische Tolerierung - Bezüge und Bezugssysteme (ISO 5459:2024)
Dieses Dokument legt die Terminologie, die Regeln und die Methodik zur Angabe und zum Verständnis von Bezügen und Bezugssystemen in technischen Produktdokumentationen fest. Darüber hinaus stellt dieses Dokument Erklärungen zur Verfügung, um den Anwender dabei zu unterstützen, die zugrunde liegenden Konzepte zu verstehen.
Dieses Dokument legt den Spezifikationsoperator (siehe ISO 17450 2) fest, der zur Bildung eines Bezugs oder Bezugssystems verwendet wird. Der Verifikationsoperator (siehe ISO 17450 2) kann unterschiedliche Formen (physikalisch oder mathematisch) annehmen und ist nicht Gegenstand dieses Dokuments.
ANMERKUNG Die ausführlichen Regeln für Maximum und Minimum Material Bedingungen für Bezüge sind in ISO 2692 angegeben.
Spécification géométrique des produits (GPS) - Tolérancement géométrique - Références spécifiées et systèmes de références spécifiées (ISO 5459:2024)
Le présent document spécifie la terminologie, les règles et la méthodologie pour indiquer et comprendre les références spécifiées et les systèmes de références spécifiées dans la documentation technique de produits. Le présent document fournit également des explications aidant l'utilisateur à la compréhension des concepts considérés.
Le présent document définit l'opérateur de spécification (voir l'ISO 17450-2) utilisé pour établir une référence spécifiée ou un système de références spécifiées. L'opérateur de vérification (voir l'ISO 17450-2) peut prendre différentes formes (physique ou mathématique) et ne fait pas l'objet du présent document.
NOTE Les règles détaillées relatives aux exigences du maximum et du minimum de matière pour les références spécifiées sont données dans l'ISO 2692.
Specifikacija geometrijskih veličin izdelka - Geometrijsko toleriranje - Reference in sistemi referenc (ISO 5459:2024)
Ta dokument določa terminologijo, pravila in metodologijo za navedbo in razumevanje referenc in sistemov referenc v tehnični dokumentaciji izdelkov. Vsebuje tudi pojasnila, ki so uporabniku v pomoč pri razumevanju vključenih pojmov.
Ta dokument opredeljuje specifikacijski operator (glej standard ISO 17450-2), ki se uporablja za določitev reference ali sistema
referenc. Verifikacijski operator (glej standard ISO 17450-2), ki je lahko v različnih oblikah (fizično ali matematično), ni predmet tega dokumenta.
OPOMBA: Podrobnejša pravila za zahteve po maksimalnem in minimalnem materialu za reference so podana v standardu ISO 2692.
General Information
Relations
Overview
EN ISO 5459:2024 - Geometrical product specifications (GPS) - Geometrical tolerancing - Datums and datum systems (ISO 5459:2024) is the third-edition international/CEN standard that defines terminology, rules and methodology for indicating and understanding datums and datum systems in technical product documentation. Published in 2024 and endorsed as EN ISO 5459:2024, it replaces the 2011 edition and updates graphical symbols, rules, and guidance to support consistent interpretation of geometrical tolerancing in engineering drawings and CAD documentation.
Key topics and requirements
- Scope and terminology: Clear definitions of datums, single datums, common datums and datum systems to standardize language in GPS and geometric tolerancing.
- Graphical language: Standard symbols and rules for datum feature indicators, datum feature identifiers, datum targets, and datum coordinate system indicators used on drawings.
- Specification operator: Defines the specification operator (per ISO 17450-2) used to establish a datum or datum system. (Note: the verification operator - how a datum is verified physically or mathematically - can take different forms and is outside this document’s scope.)
- Rules and methodology: Prescribed rules for indicating datums, datum sequencing, and the meaning of datum-related symbols to ensure unambiguous documentation and interpretation.
- Filtration and association: Treatment of filtration and association elements that affect how datum features are derived from measured surface data.
- Annexes with guidance: Normative and informative annexes provide association rules, invariance classes, worked examples, filtration guidance (including when nominal datum features are planar), and linkage to the GPS matrix model.
- Updates from 2011: Revised symbols, added new definitions, new Clause on specification operators, and expanded examples and rules.
Applications and users
EN ISO 5459:2024 is essential for anyone involved in geometric tolerancing, product documentation and verification, including:
- Design and mechanical engineers applying GD&T on drawings and CAD models
- Draftsmen and technical illustrators preparing producible documentation
- Metrology and quality engineers specifying and verifying datums during inspection
- Manufacturing and assembly engineers defining functional datum systems for production
- Standards bodies, trainers and consultants developing GPS procedures and tooling
Practical uses include unambiguous datum specification on engineering drawings, consistent datum interpretation across design-to-manufacture workflows, and guidance for developing inspection strategies and measurement software.
Related standards
- ISO 17450-2 - Specification and verification operators (specification operator referenced)
- ISO 2692 - Maximum and least material requirements for datums (detailed rules)
- ISO/TC 213 work on GPS and dimensional metrology (committee responsible)
Keywords: EN ISO 5459:2024, ISO 5459:2024, datums, datum systems, geometrical tolerancing, GPS, datum feature indicator, specification operator, technical product documentation.
Standards Content (Sample)
SLOVENSKI STANDARD
01-december-2024
Specifikacija geometrijskih veličin izdelka - Geometrijsko toleriranje - Reference in
sistemi referenc (ISO 5459:2024)
Geometrical product specifications (GPS) - Geometrical tolerancing - Datums and datum
systems (ISO 5459:2024)
Geometrische Produktspezifikation (GPS) - Geometrische Tolerierung - Bezüge und
Bezugssysteme (ISO 5459:2024)
Spécification géométrique des produits (GPS) - Tolérancement géométrique -
Références spécifiées et systèmes de références spécifiées (ISO 5459:2024)
Ta slovenski standard je istoveten z: EN ISO 5459:2024
ICS:
17.040.10 Tolerance in ujemi Limits and fits
17.040.40 Specifikacija geometrijskih Geometrical Product
veličin izdelka (GPS) Specification (GPS)
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EN ISO 5459
EUROPEAN STANDARD
NORME EUROPÉENNE
October 2024
EUROPÄISCHE NORM
ICS 17.040.40 Supersedes EN ISO 5459:2011
English Version
Geometrical product specifications (GPS) - Geometrical
tolerancing - Datums and datum systems (ISO 5459:2024)
Spécification géométrique des produits (GPS) - Geometrische Produktspezifikation (GPS) -
Tolérancement géométrique - Références spécifiées et Geometrische Tolerierung - Bezüge und
systèmes de références spécifiées (ISO 5459:2024) Bezugssysteme (ISO 5459:2024)
This European Standard was approved by CEN on 27 July 2024.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2024 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 5459:2024 E
worldwide for CEN national Members.
Contents Page
European foreword . 3
European foreword
This document (EN ISO 5459:2024) has been prepared by Technical Committee ISO/TC 213
"Dimensional and geometrical product specifications and verification" in collaboration with Technical
Committee CEN/TC 290 “Dimensional and geometrical product specification and verification” the
secretariat of which is held by AFNOR.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by April 2025, and conflicting national standards shall be
withdrawn at the latest by April 2025.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 5459:2011.
Any feedback and questions on this document should be directed to the users’ national standards
body/national committee. A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and the
United Kingdom.
Endorsement notice
The text of ISO 5459:2024 has been approved by CEN as EN ISO 5459:2024 without any modification.
International
Standard
ISO 5459
Third edition
Geometrical product specifications
2024-10
(GPS) — Geometrical tolerancing —
Datums and datum systems
Spécification géométrique des produits (GPS) — Tolérancement
géométrique — Références spécifiées et systèmes de références
spécifiées
Reference number
ISO 5459:2024(en) © ISO 2024
ISO 5459:2024(en)
© ISO 2024
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
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ISO copyright office
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Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii
ISO 5459:2024(en)
Contents Page
Foreword .v
Introduction .vii
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols . 5
5 Role of datums . 7
6 General concepts . 9
6.1 General .9
6.2 Intrinsic characteristics of surfaces associated with datum features .10
6.2.1 General .10
6.2.2 Single datum established from a single feature .11
6.2.3 Common datum established from two or more single features simultaneously .11
6.2.4 Datum systems established in a defined sequence from two or more single
features . 13
6.3 Single datums, common datums and datum systems . 13
6.3.1 General . 13
6.3.2 Single datums . 13
6.3.3 Common datums . .14
6.3.4 Datum systems. 15
7 Graphical language .18
7.1 General .18
7.2 Indication of datum features .18
7.2.1 Datum feature indicator .18
7.2.2 Datum feature identifier.19
7.2.3 Datum targets .19
7.3 Specification of datums and datum systems . 23
7.4 Indication and meaning of rules .24
7.4.1 General .24
7.4.2 Rules .24
8 Specification operators for datum .47
8.1 ISO default specification operator for datum .47
8.2 Special specification operator for datum .47
8.2.1 General .47
8.2.2 Filtration specification elements for datum . 48
8.2.3 Association specification elements for datum . 49
8.3 Drawing-default specification operator for datums . 50
Annex A (normative) Association for datums . .51
Annex B (informative) Invariance classes . 61
Annex C (informative) Examples .63
Annex D (informative) Former practices .86
Annex E (informative) Examples of a datum system or a common datum established with
contacting features .90
Annex F (normative) Relations and dimensions of graphical symbols .96
Annex G (normative) Establishment of a datum coordinate system from a datum system .99
Annex H (informative) Filter symbols and attached nesting index .103
Annex I (informative) Issue of orientation and location constraints in datum systems .104
iii
ISO 5459:2024(en)
Annex J (normative) Filtration of a datum feature which is nominally a plane .111
Annex K (informative) Relation to the GPS matrix model .114
Bibliography .115
iv
ISO 5459:2024(en)
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 213, Dimensional and geometrical product
specifications and verification, collaboration with the European Committee for Standardization (CEN)
Technical Committee CEN/TC 290, Dimensional and geometrical product specification and verification, in
accordance with the Agreement on technical cooperation between ISO and CEN (Vienna Agreement).
This third edition cancels and replaces the second edition (ISO 5459:2011), which has been technically
revised.
The main changes are as follows:
— update of the Normative references and Bibliography;
— addition of definitions 3.20, 3.20.1 and 3.20.2;
— in Table 1, update of the symbol of the datum feature indicator;
— in Table 1, addition of the symbol of single datum target indicator, moveable datum target indicator,
restricted datum feature, indication of a situation feature and datum coordinate system indicator, and
addition of a note;
— in Table 2, addition of [SV], [SF] and [SFxx], and addition of a note;
— in Clause 6, addition of a paragraph before the example in 6.1, update of 6.2.1 and 6.2.2, replacement
of the first paragraph in 6.2.3 and 6.2.4, addition of the last paragraph in 6.3.2 and table titles added in
6.3.2 and subsequent tables renumbered;
— in Clause 7, addition of a note in 7.1, update of 7.2.1, 7.3, 7.4.2.1 and 7.4.2.2, update of the text and figures
in 7.4.2.4 up to Figure 22, update of the first paragraph of 7.4.2.6, update of Figure 39, addition of a new
rule 11 in 7.4.2.11 and a new rule 12 in 7.4.2.12;
— addition of a new Clause 8;
— in Annex A, update of the text between Figures A.1 and A.2, update of the first paragraph in A.2.1 and of
Figure A.4, addition of Notes 1 and 2 in A.2.2.3, and update of the row for the plane in Table A.2;
v
ISO 5459:2024(en)
— addition of a new Clause D.4;
— update of Annex F, addition of new Annexes G to J, update of Annex K giving the relation to the GPS matrix
model.
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.
vi
ISO 5459:2024(en)
Introduction
This document is a geometrical product specification (GPS) standard and is to be regarded as a general GPS
standard (see ISO 14638). It influences chain links A to C of the chains of standards on datums.
The ISO GPS matrix model given in ISO 14638 gives an overview of the ISO GPS system of which this document
is a part. The fundamental rules of ISO GPS given in ISO 8015 apply to this document and the default decision
rules given in ISO 14253-1 apply to the specifications made in accordance with this document, unless
otherwise indicated.
For more detailed information on the relationship of this document to other standards and the GPS matrix
model, see Annex K.
For the definitive presentation (proportions and dimensions) of symbols for geometrical tolerancing, see
ISO 7083.
The previous version of this document dealt only with planes, cylinders and spheres being used as datums.
There is a need to consider all types of surfaces, which are increasingly used in industry. The definitions of
classes of surfaces as given in Annex B are exhaustive and unambiguous.
This document applies new concepts and terms that have not been used in previous ISO GPS standards. These
concepts are described in detail in ISO 14638, ISO 17450-1 and ISO 17450-2; therefore, it is recommended to
refer to these standards when using this document.
This document provides tools to express location or orientation constraints, or both, for a tolerance zone.
It does not provide information about the relationship between datums or datum systems and functional
requirements or applications.
vii
International Standard ISO 5459:2024(en)
Geometrical product specifications (GPS) — Geometrical
tolerancing — Datums and datum systems
1 Scope
This document specifies terminology, rules and methodology for the indication and understanding of datums
and datum systems in technical product documentation. This document also provides explanations to assist
the user in understanding the concepts involved.
This document defines the specification operator (see ISO 17450-2) used to establish a datum or datum
system. The verification operator (see ISO 17450-2) can take different forms (physically or mathematically)
and is not the subject of this document.
NOTE The detailed rules for maximum and least material requirements for datums are given in ISO 2692.
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 128-2:2022, Technical product documentation (TPD) — General principles of representation — Part 2: Basic
conventions for lines
ISO 1101, Geometrical product specifications (GPS) — Geometrical tolerancing — Tolerances of form,
orientation, location and run-out
ISO 2692, Geometrical product specifications (GPS) — Geometrical tolerancing — Maximum material
requirement (MMR), least material requirement (LMR) and reciprocity requirement (RPR)
ISO 4351, Geometrical product specifications (GPS) — Association
ISO 17450-1, Geometrical product specifications (GPS) — General concepts — Part 1: Model for geometrical
specification and verification
ISO 17450-2, Geometrical product specifications (GPS) — General concepts — Part 2: Basic tenets, specifications,
operators, uncertainties and ambiguities
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 1101, ISO 2692, ISO 4351,
ISO 17450-1, ISO 17450-2 and the following 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
situation feature
point, straight line, plane or helix from which the location and orientation of features, or both, can be defined
ISO 5459:2024(en)
3.2
datum feature
real (non-ideal) integral feature used for establishing a datum
Note 1 to entry: A datum feature can be a complete surface, a portion of a complete surface, or a feature of size.
Note 2 to entry: An illustration showing the relations between datum feature, associated feature and datum is given
in Figure 4.
3.3
associated feature
associated feature for establishing a datum
ideal feature which is fitted to the datum feature with a specific association criterion
Note 1 to entry: The type of the associated feature is by default the same as the type of the nominal integral feature
used to establish the datum (for an exception, see 7.4.2.5).
Note 2 to entry: The associated feature for establishing a datum simulates the contact between the real surface of the
workpiece and other components.
Note 3 to entry: An illustration showing the relations between datum feature, associated feature and datum is given
in Figure 4.
3.4
datum
one or more situation features of one or more features associated with one or more real integral features
selected to define the location or orientation, or both, of a tolerance zone or an ideal feature representing for
instance a virtual condition
Note 1 to entry: A datum is a theoretically exact reference; it is defined by a plane, a straight line or a point, or a
combination thereof.
Note 2 to entry: The concept of datums is inherently reliant upon the invariance class concept (see Annexes A and B).
Note 3 to entry: Datums with maximum material condition (MMC) or least material condition (LMC) are not covered
in this document (see ISO 2692).
Note 4 to entry: When a datum is established, for example, on a complex surface, the datum consists of a plane, a
straight line or a point, or a combination thereof. The modifier [SL], [PL] or [PT], or a combination thereof, can be
attached to the datum identifier to limit the situation feature(s) taken into account relative to the surface.
Note 5 to entry: An illustration showing the relation between datum feature, associated feature and datum is given in
Figure 4.
3.5
primary datum
datum that is not influenced by constraints from other datums
3.6
secondary datum
datum, in a datum system, that is influenced by an orientation constraint from the primary datum in the
datum system
3.7
tertiary datum
datum, in a datum system, that is influenced by constraints from the primary datum and the secondary
datum in the datum system
3.8
single datum
datum established from one datum feature taken from a single surface or from one feature of size
Note 1 to entry: The invariance class of a single surface can be complex, prismatic, helical, cylindrical, revolute, planar
or spherical. A set of situation features defining the datum (see Table B.1) corresponds to each type of single surface.
ISO 5459:2024(en)
3.9
common datum
datum established from two or more datum features considered simultaneously
Note 1 to entry: To define a common datum, it is necessary to consider the collection surface created by the considered
datum features. The invariance class of a collection surface can be complex, prismatic, helical, cylindrical, revolute,
planar or spherical (see Table B.1).
3.10
datum system
set of two or more situation features established in a specific order from two or more datum features
Note 1 to entry: To define a datum system, it is necessary to consider the collection surface created by the considered
datum features. The invariance class of a collection surface can be complex, prismatic, helical, cylindrical, revolute,
planar or spherical (see Table B.1).
3.11
datum target
portion of a datum feature which can nominally be a point, a line segment or an area
Note 1 to entry: Where the datum target is a point, a line or an area, it is indicated as a datum target point, a datum
target line or a datum target area, respectively.
3.12
moveable datum target
datum target with a controlled motion
3.13
collection surface
two or more surfaces considered simultaneously as a single surface
Note 1 to entry: Table B.1 is used to determine the invariance class of a datum or datum systems when using a
collection of surfaces.
Note 2 to entry: Two intersecting planes may be considered together or separately. When the two intersecting planes
are considered simultaneously as a single surface, that surface is a collection surface.
3.14
objective function
formula that describes the goal of association from the datum feature and the ideal feature
(associated feature)
Note 1 to entry: In this document, the term “objective function” refers to “objective function for association”.
Note 2 to entry: The objective functions are usually named and mathematically described: maximum inscribed,
minimum zone, etc.
[SOURCE: ISO 4351:2023, 3.6, modified — “datum feature” replaced “input feature”. Notes to entry added.]
3.15
constraint
set of restrictions on variability of the mathematical parameters describing an associated feature (3.3) in the
optimization process
EXAMPLE Orientation constraint, location constraint, material constraint or intrinsic characteristic constraint
are the different types of constraint.
[SOURCE: ISO 4351:2023, 3.9, modified — “constraint” replaced “association constraint” as the term and in
the example. “intrinsic characteristic constraint” replaced “size constraint” in the example.]
ISO 5459:2024(en)
3.15.1
orientation constraint
constraint (3.15) related to one or more rotational degrees of freedom of associated feature (3.3)
[SOURCE: ISO 4351:2023, 3.10, modified — “constraint” replaced “association constraint”.]
3.15.2
location constraint
constraint (3.15) related to one or more translational degrees of freedom of associated feature (3.3)
[SOURCE: ISO 4351:2023, 3.11, modified — “constraint” replaced “association constraint”.]
3.15.3
material constraint
constraint (3.15) on the associated feature (3.3), in relation to the material boundary of the datum feature
(3.2)
EXAMPLE The outside material constraint implies that all distances between the associated feature and the
datum feature are negative or equal to zero.
[SOURCE: ISO 4351:2023, 3.12, modified — “constraint” replaced “association constraint” and “datum
feature” replaced “input feature”.]
3.15.4
intrinsic characteristic constraint
size constraint
association constraint (3.15) on an intrinsic characteristic of associated feature (3.3) whether it is considered
fixed or variable
Note 1 to entry: The intrinsic characteristic of a cylinder is its diameter which is a size.
Note 2 to entry: In the collection surface, constituted by two parallel and not coaxial cylinders, there are more than
one intrinsic characteristic (two diameters, the distance between their axes and the angle of 0°).
3.16
association criterion
objective function with or without constraints, defined for an association
Note 1 to entry: Several constraints may be defined for an association.
Note 2 to entry: Association results (associated features) may differ, depending upon the choice of association
criterion.
Note 3 to entry: Default association criteria are defined in Annex A.
3.17
integral feature
surface or line on a surface
Note 1 to entry: An integral feature is intrinsically defined.
3.18
contacting feature
ideal feature of any type which is different from the nominal feature under consideration and is associated
with the corresponding datum feature
Note 1 to entry: See Figure 1.
ISO 5459:2024(en)
a) Contacting feature on nominal model b) Contacting feature on real workpiece
Key
1 contacting feature: ideal sphere in contact with the datum feature or the feature under consideration
2 features under consideration: nominal trapezoidal slot (collection of two non-parallel surfaces)
3 datum feature: real feature corresponding to the trapezoidal slot (collection of two non-parallel surfaces)
Figure 1 — Example of a contacting feature
3.19
invariance class
group of ideal features for which the nominal surface is invariant for the same degrees of freedom
Note 1 to entry: There are seven invariance classes (see Annex B).
3.20
datum coordinate system
coordinate system established from a single datum, a common datum or a datum system
Note 1 to entry: Using a datum coordinate system is optional.
3.20.1
datum coordinate system indicator
indication defining a coordinate system
3.20.2
datum coordinate system identifier
label identifying a coordinate system
4 Symbols
Table 1 gives symbols to identify the datum feature and datum target used to establish a datum.
Table 2 gives the list of modifier symbols, which can be associated the datum identifier.
ISO 5459:2024(en)
Table 1 — Datum features and datum target symbols
Description Symbol Sub-
clause
Datum feature indicator 7.2.1
Datum feature identifier Capital letter (A, B, C, AA, etc.) 7.2.2
Single datum target frame 7.2.3.2
Moveable datum target frame 7.2.3.2
a
Single datum target indicator 7.2.3
Moveable datum target
7.2.3
a
indicator
Datum target point 7.2.3.3
Closed datum target line 7.2.3.3
Non-closed datum target line 7.2.3.3
Datum target area 7.2.3.3
Restricted datum feature 7.4.2.4
a
The terminator of the leader line is dependent of the type of datum target.
ISO 5459:2024(en)
TTaabblle 1 e 1 ((ccoonnttiinnueuedd))
Description Symbol Sub-
clause
Indication of a situation feature
of a single datum, a common 7.4.2.12
datum or a datum system
For single datum For datum system
Datum coordinate system indi-
Annex G
cator
a
The terminator of the leader line is dependent of the type of datum target.
Table 2 — Modifier symbols
Symbol Description Subclause
[PD] Pitch diameter 7.4.2.1
[MD] Major diameter 7.4.2.1
[LD] Minor diameter 7.4.2.1
[ACS] Any cross-section 7.4.2.4
[ALS] Any longitudinal section 7.4.2.4
[CF] Contacting feature 7.4.2.5
[SV] Size, variable 7.4.2.2
[SF] Size, fixed 7.4.2.2
[SFxx] Size, fixed with specified value xx 7.4.2.2
[DV] Distance, variable (for common datum) 7.4.2.7
[PT] (situation feature of type) point 7.4.2.8
[SL] (situation feature of type) straight line 7.4.2.8
[PL] (situation feature of type) plane 7.4.2.8
>< For orientation constraint only 7.4.2.8
Projected (for secondary or tertiary datum)
7.4.2.10
Least material requirement
See ISO 2692
Maximum material requirement
See ISO 2692
NOTE Other symbols related to filtration and association are presented in Tables 8 to 10 and in Table H.1.
5 Role of datums
Datums form part of a geometrical specification (see ISO 1101).
Datums are established from real surfaces identified on a workpiece.
ISO 5459:2024(en)
Datums allow tolerance zones to be located or orientated (see Examples 1 and 2) and virtual conditions to
be defined (for example maximum material virtual condition according to ISO 2692). The datums can be
seen as a means to lock degrees of freedom of a tolerance zone. The number of degrees of freedom of the
tolerance zone which are locked depends on the nominal shape of the features utilized to establish the datum
or datum system; whether the datum is primary, secondary or tertiary; and on the toleranced characteristic
indicated in the geometrical tolerance frame.
By default, a datum locks all the degrees of freedom of the tolerance zone that it can lock given its shape and
which
— are required by the geometrical characteristic indicated in the tolerance frame, and
— have not already been locked by the preceding datum(s) in the datum system.
When a datum locks only orientation degrees of freedom, this shall be indicated by the modifier >< .
EXAMPLE 1 The tolerance zone, which is the space between two parallel planes 0,1 mm apart, is constrained in
orientation by a 75° theoretically exact angle from the datum. Here, the datum is the situation feature of a cylinder
(axis of associated cylinder). See Figure 2.
Dimensions in millimetres
a) Indication on the drawing b) Illustration of tolerance zone
Key
1 datum A constituted by the axis of the associated cylinder
Figure 2 — Example of tolerance zone constrained in orientation from a datum
EXAMPLE 2 The tolerance zone, which is the space between two parallel planes 0,2 mm apart, is constrained
in orientation by a 70° angle from a datum, and in location by the distance 20 mm from the gauge plane positioned
perpendicular to the axis of 40° cone where its local diameter is 30 mm. Here, the datum consists of the set of situation
features of the cone with a fixed angle of 40°, i.e. the cone axis and the point of intersection between the gauge plane
and that axis. See Figure 3.
ISO 5459:2024(en)
Dimensions in millimetres
a) Indication on the drawing b) Illustration of tolerance zone
Key
1 datum A constituted by the axis of the associated cone, the point of intersection of the gauging plane and this axis
Figure 3 — Example of a tolerance zone constrained in location from a datum
6 General concepts
6.1 General
Datums and datum systems are theoretically exact geometric features used together with implicit or explicit
TEDs to locate or orientate
a) tolerance zones for toleranced features, or
b) virtual conditions, e.g. in the case of maximum material requirement (see ISO 2692).
A datum consists of a set of situation features for an ideal feature (feature of perfect form). This ideal feature
is an associated feature which is established from the identified datum features of a workpiece. Datum
features can be complete features, or identified portions thereof (see Clause 7).
A datum system consists of more than one datum.
The geometrical type of these associated features belongs to one of the following invariance classes:
— spherical (i.e. a sphere);
— planar (i.e. a plane);
— cylindrical (i.e. a cylinder);
ISO 5459:2024(en)
1)
— helical (e.g. a threaded surface) ;
— revolute (e.g. a cone or a torus);
— prismatic (e.g. a prism);
— complex (e.g. a free-form surface).
Each single or collection feature belongs to one invariance class (for an explanation of invariance classes,
invariance degree, and degree of freedom, see Annex B).
Associated features are established from the real or extracted single features used for the datum. The
associated feature can be defined by an operation of association including constraints coming from the
feature itself or from one or more other features. The situation features that make up the datum are defined
from these associated features. The default association methods are given in Annex A.
One or more single features can be used to establish a datum. If only one single feature is used, it establishes
a single datum. If more than one single feature is used, they can either be considered simultaneously to
establish a common datum or in a predefined order to establish a datum system (see 6.3).
The datum feature(s) to be used for establishing each datum shall be designated and identified.
The single datums (see 6.3.2), common datums (see 6.3.3) or datum systems (see 6.3.4), as applicable, shall
be specified for each geometrical specification.
When applicable, any additional constraints shall be defined for the association.
Datums and datum systems are situation features, not coordinate systems. The set of situation feature is
established in a process including associations, but can also include some other geometrical operations (e.g.
intersection, translation, rotation). A complete datum system (allowing to lock all six degrees of freedom)
is a set of one point, one straight line and one plane (the point on the straight line in the plane). Coordinate
systems can be established from a datum or a datum system that locks all six degrees of freedom. In this
case, it shall be indicated in accordance with Annex G.
EXAMPLE In Figure 4, the datum is indicated as a single datum derived from a nominal feature, a cylinder, used to
orientate or locate a tolerance zone. In order to derive the datum, the following sequence of operations is performed:
— a partition to define the real integral surface corresponding to the nominal feature [see Figure 4 b)];
— an extraction to provide the extracted integral feature [see Figure 4 c)];
— a filtration (see Annex A);
— an association (see Annex A for association method) to define the associated feature. (In this case, its type is the
same as the nominal feature.) The associated feature [see Figure 4 d)] is established from the non-ideal surface (in
the specification process) or from the extracted feature (in the verification process).
The datum is defined as the situation feature (the axis) of the associated cylinder [see Figure 4 e)].
6.2 Intrinsic characteristics of surfaces associated with datum features
6.2.1 General
The default status (variable or fixed) of the intrinsic characteristics is described in 6.2.2, 6.2.3 or 6.2.4. For
rules, see also rule 2 (2A to 2D) in 7.4.2.2.
For datums with virtual conditions, see ISO 2692.
Issues of orientation and location constraints in datum systems are presented in Annex I.
1) Helical surfaces as such are not considered in this document. They are regarded as cylindrical surfaces because,
in most functional cases where helical surfaces (threads, helical slope, endless screw, etc.) are involved, the combined
rotation and translation of the helix is not needed for datum purposes. In these cases, the pitch cylinder surface is used to
establish the datum. The major or minor cylindrical surface can also be considered and specified.
ISO 5459:2024(en)
6.2.2 Single datum established from a single feature
The default status of the intrinsic characteristics for a single feature is:
— variable for the linear size of a feature of size (see Table 3);
— fixed for the angular size of a feature of size (see Table 3);
— fixed for an intrinsic characteristic which is not the linear size of a feature of size.
Table 3 — Default status of intrinsic characteristics of features of size
Feature of size Invariance class Intrinsic characteristic Default status
Variable
Cylinder Cylindrical Diameter
See example in C.2.2
Variable
Sphere Spherical Diameter
See example in C.2.4
Variable
Two parallel opposite planes Planar Distance between the two planes
See example in C.2.10
Fixed
Cone Revolute Angle
See example in C.2.3
Fixed
Wedge Prismatic Angle
See example in C.2.9
6.2.3 Common datum established from two or more single features simultaneously
The default status (variable or fixed) of the intrinsic characteristics of each associated feature establishing
the common datum is as in 6.2.2.
Intrinsic characteristics introduced by the collection of features (defining the relation between the associated
features) shall by default be considered theoretically exact for both linear and angular dimensions.
ISO 5459:2024(en)
a) Drawing b) Integral real c) Extraction
...
Frequently Asked Questions
SIST EN ISO 5459:2024 is a standard published by the Slovenian Institute for Standardization (SIST). Its full title is "Geometrical product specifications (GPS) - Geometrical tolerancing - Datums and datum systems (ISO 5459:2024)". This standard covers: This document specifies terminology, rules and methodology for the indication and understanding of datums and datum systems in technical product documentation. This document also provides explanations to assist the user in understanding the concepts involved. This document defines the specification operator (see ISO 17450-2) used to establish a datum or datum system. The verification operator (see ISO 17450-2) can take different forms (physically or mathematically) and is not the subject of this document. NOTE The detailed rules for maximum and least material requirements for datums are given in ISO 2692.
This document specifies terminology, rules and methodology for the indication and understanding of datums and datum systems in technical product documentation. This document also provides explanations to assist the user in understanding the concepts involved. This document defines the specification operator (see ISO 17450-2) used to establish a datum or datum system. The verification operator (see ISO 17450-2) can take different forms (physically or mathematically) and is not the subject of this document. NOTE The detailed rules for maximum and least material requirements for datums are given in ISO 2692.
SIST EN ISO 5459:2024 is classified under the following ICS (International Classification for Standards) categories: 17.040.10 - Limits and fits; 17.040.40 - Geometrical Product Specification (GPS). The ICS classification helps identify the subject area and facilitates finding related standards.
SIST EN ISO 5459:2024 has the following relationships with other standards: It is inter standard links to SIST EN ISO 5459:2011. Understanding these relationships helps ensure you are using the most current and applicable version of the standard.
You can purchase SIST EN ISO 5459:2024 directly from iTeh Standards. The document is available in PDF format and is delivered instantly after payment. Add the standard to your cart and complete the secure checkout process. iTeh Standards is an authorized distributor of SIST standards.
The SIST EN ISO 5459:2024 standard provides a comprehensive framework for understanding the concept of geometrical tolerancing, specifically focusing on datums and datum systems within technical product documentation. Its scope is well-defined, addressing the terminology, rules, and methodologies necessary for the accurate indication and comprehension of these critical elements in product specifications. A significant strength of this standard is its structured approach to defining the specification operator, as referenced in ISO 17450-2. This clarity is essential for professionals dealing with complex geometrical product specifications, as it lays down a solid foundation for establishing datums effectively. The inclusion of explanations and guidance further enhances usability, making it easier for users to grasp the essential concepts involved without extensive prior knowledge. Moreover, the standard's emphasis on providing detailed rules surrounding maximum and least material requirements for datums, although mentioned as part of ISO 2692, underscores the interconnected nature of geometrical tolerancing. This relationship enhances the overall relevancy of SIST EN ISO 5459:2024, ensuring that users are not only equipped with the necessary definitions but also with an understanding of how these elements operate within broader engineering and manufacturing contexts. In summary, SIST EN ISO 5459:2024 stands out due to its clear specification of terminology, robust methodological framework, and practical explanations, making it an invaluable resource for professionals involved in geometrical product specifications and tolerancing. Its relevance in the industry is reaffirmed by its alignment with existing standards, ensuring a cohesive approach to geometrical tolerancing practices across various applications.
SIST EN ISO 5459:2024は、技術的製品文書における基準点および基準システムの指示と理解のための用語、ルール、手法を規定した重要な標準ドキュメントです。この文書は、基準点および基準システムに関わる概念を理解するための説明も提供しており、ユーザーにとって非常に有用です。 この標準の強みは、基準点の設定および基準システムの確立に関する仕様演算子を明確に定義している点です。仕様演算子の定義により、ユーザーは設計や製造プロセスにおいて、適切な基準を選んで使用することが可能になります。また、基準に関連する詳細な最大および最小材料要件については、ISO 2692で言及されているため、ユーザーはさらに深く理解することができるようになります。 さらに、この標準は幾何公差（GPS）の重要性を強調しており、特に製品の設計と品質管理において不可欠な要素です。基準点および基準システムの明確な理解は、技術製品の相互運用性を高め、エラーを減少させるために重要です。そのため、SIST EN ISO 5459:2024は、製造業界における標準化の進展に寄与するものといえるでしょう。 したがって、このドキュメントは、基準点および基準システムを扱うすべての技術者にとって、欠かせないガイドとなることは間違いありません。全体として、SIST EN ISO 5459:2024は、設計および製造プロセスにおける基準設定の正確さと効率を向上させるための不可欠なリソースです。
SIST EN ISO 5459:2024는 기하적 제품 사양(GPS) 분야에서 기하적 공차 및 기준 시스템에 대한 중요하고 체계적인 지침을 제공합니다. 이 표준은 기술 제품 문서에서 기준 및 기준 시스템의 표기와 이해를 위한 용어, 규칙 및 방법론을 명확히 정의하고 있습니다. 본 문서는 기준을 설정하거나 기준 시스템을 수립하는 데 사용하는 사양 작업자를 정의합니다. 또한, 기준과 관련된 다양한 개념을 이해하는 데 도움을 주기 위한 설명을 제공하므로, 사용자들이 해당 내용을 보다 쉽게 이해하고 활용할 수 있도록 지원합니다. 이러한 점에서 SIST EN ISO 5459:2024는 기술 문서의 명확성과 일관성을 높이는 데 기여합니다. 또한 이 표준은 ISO 17450-2에 기술된 확인 작업자가 다양한 형태(물리적 또는 수학적)로 나타날 수 있음을 언급하며, 이러한 접근 방식을 통해 기준 시스템의 적용과 검증에 대한 깊이 있는 이해를 제공합니다. SIST EN ISO 5459:2024의 강점 중 하나는 명확한 불확실성 감소에 있으며, 이는 다양한 산업 분야에서 제품 설계 및 제작 과정의 품질과 효율성을 높이는 데 매우 중요한 역할을 합니다. 또한 ISO 2692에서 제공되는 최대 및 최소 재료 요구사항에 대한 상세 규칙은 기준 설정에 대한 보다 구체적인 지침을 하여, 사용자가 기준과 공차를 효과적으로 관리할 수 있도록 지원합니다. 결론적으로, SIST EN ISO 5459:2024는 기하적 공차와 기준 시스템에 대한 종합적인 이해를 제공하며, 이를 통해 기술 제품 문서의 신뢰성과 통일성을 강화하는 데 중요한 역할을 합니다.
Die Norm SIST EN ISO 5459:2024 bietet eine umfassende und präzise Grundlage für die geometrischen Produktspezifikationen (GPS), insbesondere im Hinblick auf geometrische Toleranzen, Datums und Datumssysteme. Ihr Anwendungsbereich erstreckt sich auf die Terminologie, Regeln und Methodik zur Kennzeichnung und dem Verständnis von Datums und Datumssystemen in der technischen Produktdokumentation. Ein herausragendes Merkmal dieser Norm ist ihre Fähigkeit, komplexe Konzepte verständlich zu machen, was insbesondere für Ingenieure und Designer von großem Nutzen ist. Durch die Bereitstellung klarer Erklärungen hilft die Norm den Anwendern, die relevanten Konzepte tiefgreifend zu erfassen. Weiterhin legt die Norm fest, wie der Spezifikationsoperator gemäß ISO 17450-2 verwendet wird, um ein Datum oder Datumssystem zu definieren. Dies ist entscheidend für die Sicherstellung konsistenter und nachvollziehbarer Produktdokumentationen. Die Norm behandelt die verschiedenen Formen des Verifizierungsoperators, was eine flexible Anwendung in der praktischen Umsetzung ermöglicht, auch wenn diese Aspekte nicht Gegenstand des Dokuments sind. Ein zusätzlicher Pluspunkt der SIST EN ISO 5459:2024 ist die Verweisung auf ISO 2692, wo detaillierte Regeln für maximale und minimale Materialanforderungen für Datums behandelt werden. Diese Verbindung zu existierenden Normen stärkt die Relevanz dieser Dokumentation und fördert ein integriertes Verständnis innerhalb der Normenlandschaft. Insgesamt erscheint die SIST EN ISO 5459:2024 als eine essentielle Norm für Fachkräfte, die in der technischen Produktdokumentation tätig sind, und stellt sicher, dass die Grundlagen für eine klare und präzise Kommunikation bezüglich geometrischer Toleranzen gelegt werden. Die Norm ist relevant für ein breites Spektrum von Industrien, in denen genaue Produktspezifikationen erforderlich sind, um die Qualität und Funktionalität von Produkten zu gewährleisten.
La norme SIST EN ISO 5459:2024 traite des spécifications géométriques des produits (GPS) en se concentrant sur le dimensionnement géométrique des datums et des systèmes de datums. Ce document est essentiel car il établit une terminologie claire et des règles méthodologiques pour l'indication et la compréhension des datums dans la documentation technique des produits. Parmi les forces de cette norme, on peut souligner sa capacité à clarifier les concepts liés aux datums, ce qui est crucial pour garantir une communication cohérente entre les concepteurs, les fabricants et les clients. La norme offre également des explications détaillées qui aident les utilisateurs à naviguer dans les complexités de la tolérance géométrique, renforçant ainsi l'efficacité du documentation technique. De plus, la définition de l'opérateur de spécification, mentionnée dans le cadre de la norme ISO 17450-2, fournit un cadre solide pour établir un datum ou un système de datums. Bien que la norme ne traite pas des opérateurs de vérification, elle crée néanmoins un fondement pour leur compréhension ultérieure, ce qui est un atout pour les ingénieurs et techniciens. La pertinence de la norme SIST EN ISO 5459:2024 ne peut être sous-estimée, car elle répond aux besoins croissants en matière de standardisation dans le domaine de la fabrication et de l'ingénierie. En standardisant les règles relatives aux datums et systèmes de datums, cette norme contribue à réduire les ambiguïtés, à améliorer la qualité des produits et à faciliter les échanges internationaux. Les règles détaillées pour les exigences maximales et minimales en matière de matériau, supplémentaires dans la norme ISO 2692, complètent encore la pertinence de SIST EN ISO 5459:2024 dans le cadre des spécifications géométriques des produits. En somme, la norme SIST EN ISO 5459:2024 représente une avancée significative dans la clarification des procédures de tolérance géométrique, en fournissant des lignes directrices claires et précises qui favorisent une meilleure alignement entre les différents acteurs du secteur.
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