Geometrical product specifications (GPS) - Geometrical tolerancing - Pattern and combined geometrical specification (ISO 5458:2018)

This document establishes complementary rules to ISO 1101 to be applied to pattern specifications and defines rules to combine individual specifications, for geometrical specifications e.g. using the symbols POSITION, SYMMETRY, LINE PROFILE and SURFACE PROFILE, as well as STRAIGHTNESS (in the case where the toleranced features are nominally coaxial) and FLATNESS (in the case where the toleranced features are nominally coplanar) as listed in Annex C.
These rules apply when a set of tolerance zones are grouped together with location or orientation constraints, through the use of the CZ, CZR or SIM modifiers.
This document does not cover the use of the pattern specifications when the least and maximum material requirement is applied (see ISO 2692).
This document does not cover the establishment of common datum (see ISO 5459) based on pattern features.

Geometrische Produktspezifikationen (GPS) - Geometrische Tolerierung - Elementgruppen und kombinierte geometrische Spezifikation (ISO 5458:2018)

Dieses Dokument legt ergänzende Regeln zu ISO 1101 fest, die auf Elementgruppenspezifikationen anzuwenden sind, und definiert Regeln zur Kombination einzelner Spezifikationen für geometrische Spezifikationen, z. B. durch Verwenden der Symbole POSITION, SYMMETRIE, LINIENPROFIL und FLÄCHENPROFIL sowie GERADHEIT (wenn die tolerierten Geometrieelemente nominal koaxial sind) und EBENHEIT (wenn die tolerierten Geometrieelemente nominal koplanar sind) wie in Anhang C angegeben.
Diese Regeln gelten, wenn eine Reihe von Toleranzzonen durch Verwenden der CZ-, CZR- oder SIM-Modifikatoren mit Nebenbedingungen für Ort oder Richtung zusammengefasst werden.
Dieses Dokument behandelt nicht das Anwenden der Elementgruppenspezifikationen, wenn die Minimum- und die Maximum-Material-Bedingung angewendet wird (siehe ISO 2692).
Dieses Dokument behandelt nicht das Festlegen eines gemeinsamen Bezugs (siehe ISO 5459) basierend auf Gruppenelementen.

Spécification géométrique des produits (GPS) - Tolérancement géométrique - Spécification géométrique de groupes d'éléments et spécification géométrique combinée (ISO 5458:2018)

Le présent document établit des règles complémentaires de celles de l'ISO 1101 à appliquer aux spécifications de groupes d'éléments et définit des règles pour combiner des spécifications individuelles, pour les spécifications géométriques, par exemple en utilisant les symboles de LOCALISATION, SYMÉTRIE, PROFIL DE LIGNE et PROFIL DE SURFACE, ainsi que les symboles de RECTITUDE (dans le cas où les éléments tolérancés sont nominalement coaxiaux) et de PLANÉITÉ (dans le cas où les éléments tolérancés sont nominalement coplanaires) comme listés en Annexe C.
Ces règles s'appliquent lorsqu'un ensemble de zones de tolérances sont regroupées ensemble avec des contraintes de position ou d'orientation, en utilisant les modificateurs CZ, CZR ou SIM.
Le présent document ne couvre pas l'utilisation des spécifications de groupes d'éléments lorsque l'exigence du minimum et du maximum de matière s'applique (voir l'ISO 2692).
Le présent document ne couvre pas non plus l'établissement de référence spécifiée commune (voir l'ISO 5459) basée sur des éléments de groupe d'éléments.

Specifikacija geometrijskih veličin izdelka (GPS) - Geometrijsko toleriranje - Vzorec in kombinirane geometrijske specifikacije (ISO 5458:2018)

Ta dokument določa dopolnilna pravila k standardu ISO 1101, ki se uporabljajo za specifikacije vzorca in opredeljuje pravila za združevanje posameznih specifikacij, npr. z uporabo simbolov POLOŽAJ, SIMETRIJA, LINIJSKI PROFIL in POVRŠINSKI PROFIL ter RAVNOST (v primeru, kjer so tolerančne značilnosti nominalno koaksialne) in PLOŠČATOST (v primeru, kjer so tolerančne značilnosti nominalno koplanarne), kakor je navedeno v dodatku C.
Ta pravila se uporabljajo, ko se nabor tolerančnih območij združi z lokacijskimi ali usmeritvenimi omejitvami z uporabo modifikatorjev CZ, CZR ali SIM.
Ta dokument ne zajema uporabe specifikacije vzorca, ko se uporablja zahteva po minimalnem ali maksimalnem materialu (glej ISO 2692).
Ta dokument ne zajema določanja skupnih referenc (glej ISO 5459) na podlagi značilnosti
vzorca.

General Information

Status
Published
Publication Date
05-Jun-2018
Current Stage
6060 - Definitive text made available (DAV) - Publishing
Due Date
06-Jun-2018
Completion Date
06-Jun-2018

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SLOVENSKI STANDARD
SIST EN ISO 5458:2018
01-september-2018
1DGRPHãþD
SIST EN ISO 5458:2000
6SHFLILNDFLMDJHRPHWULMVNLKYHOLþLQL]GHOND *36 *HRPHWULMVNRWROHULUDQMH
9]RUHFLQNRPELQLUDQHJHRPHWULMVNHVSHFLILNDFLMH ,62
Geometrical product specifications (GPS) - Geometrical tolerancing - Pattern and
combined geometrical specification (ISO 5458:2018)

Geometrische Produktspezifikation (GPS) - Form und Lagetolerierung - Positions- und

Mustertolerierung (ISO 5458:2018)
Spécification géométrique des produits (GPS) - Tolérancement géométrique -

Spécification géométrique de groupes d'éléments et spécification géométrique combinée

(ISO 5458:2018)
Ta slovenski standard je istoveten z: EN ISO 5458:2018
ICS:
01.100.01 7HKQLþQRULVDQMHQDVSORãQR Technical drawings in
general
17.040.10 Tolerance in ujemi Limits and fits
17.040.40 6SHFLILNDFLMDJHRPHWULMVNLK Geometrical Product
YHOLþLQL]GHOND *36 Specification (GPS)
SIST EN ISO 5458:2018 en

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 5458:2018
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SIST EN ISO 5458:2018
EN ISO 5458
EUROPEAN STANDARD
NORME EUROPÉENNE
June 2018
EUROPÄISCHE NORM
ICS 17.040.10 Supersedes EN ISO 5458:1998
English Version
Geometrical product specifications (GPS) - Geometrical
tolerancing - Pattern and combined geometrical
specification (ISO 5458:2018)

Spécification géométrique des produits (GPS) - Geometrische Produktspezifikation (GPS) - Form und

Tolérancement géométrique - Spécification Lagetolerierung - Positions- und Mustertolerierung

géométrique de groupes d'éléments et spécification (ISO 5458:2018)
géométrique combinée (ISO 5458:2018)
This European Standard was approved by CEN on 25 February 2018.

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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,

Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,

Turkey 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

© 2018 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 5458:2018 E

worldwide for CEN national Members.
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SIST EN ISO 5458:2018
EN ISO 5458:2018 (E)
Contents Page

European foreword ....................................................................................................................................................... 3

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SIST EN ISO 5458:2018
EN ISO 5458:2018 (E)
European foreword

This document (EN ISO 5458:2018) 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 December 2018, and conflicting national standards

shall be withdrawn at the latest by December 2018.

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 5458:1998.

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, Former Yugoslav Republic of Macedonia,

France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta,

Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,

Turkey and the United Kingdom.
Endorsement notice

The text of ISO 5458:2018 has been approved by CEN as EN ISO 5458:2018 without any modification.

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SIST EN ISO 5458:2018
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SIST EN ISO 5458:2018
INTERNATIONAL ISO
STANDARD 5458
Third edition
2018-05
Geometrical product specifications
(GPS) — Geometrical tolerancing —
Pattern and combined geometrical
specification
Spécification géométrique des produits (GPS) — Tolérancement
géométrique — Spécification géométrique de groupes d'éléments et
spécification géométrique combinée
Reference number
ISO 5458:2018(E)
ISO 2018
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SIST EN ISO 5458:2018
ISO 5458:2018(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2018

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 the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address

below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2018 – All rights reserved
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SIST EN ISO 5458:2018
ISO 5458:2018(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

Introduction ..................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 1

4 Symbols and specification modifiers .............................................................................................................................................. 3

5 Principles ..................................................................................................................................................................................................................... 3

5.1 General ........................................................................................................................................................................................................... 3

5.2 Concepts ....................................................................................................................................................................................................... 4

5.3 Rule A: for position specification ............................................................................................................................................ 4

5.4 Rules for pattern specification .................................................................................................................................................. 5

5.4.1 General...................................................................................................................................................................................... 5

5.4.2 Rule B: constraints ......................................................................................................................................................... 5

5.4.3 Rule C: indication of a single indicator pattern specification .................................................... 6

5.4.4 Rule D: indication of a multiple indicator pattern specification ............................................. 8

5.4.5 Rule E: indication of multi-level single indicator pattern specification ........................12

5.5 Pattern characteristic .....................................................................................................................................................................17

Annex A (informative) Former practice, important changes ...................................................................................................18

Annex B (informative) Differences between ISO 5458:1998 and this document ...............................................20

Annex C (informative) Examples of pattern specifications ........................................................................................................22

Annex D (normative) Relations and dimensions of graphical symbols ........................................................................41

Annex E (informative) Concept diagram for pattern specification and relation with modifiers ........42

Annex F (informative) Relation to the GPS matrix model ............................................................................................................43

Bibliography .............................................................................................................................................................................................................................44

© ISO 2018 – All rights reserved iii
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SIST EN ISO 5458:2018
ISO 5458:2018(E)
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 documents 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).

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www .iso .org/patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation on 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 the following

URL: www .iso .org/iso/foreword .html.

This document was prepared by Technical Committee ISO/TC 213, Dimensional and geometrical product

specifications and verification.

This third edition cancels and replaces the second edition (ISO 5458:1998), which has been technically

revised.
The main changes to the previous edition are as follows:
— exception from the independency principle removed according to ISO 8015;
— rules harmonized to align with ISO 1101;
— unstated rules in ISO 5458:1998 removed;

— concept of “pattern” to control all types of geometrical features introduced more generically, rather

than applying it only with position symbol.
iv © ISO 2018 – All rights reserved
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SIST EN ISO 5458:2018
ISO 5458:2018(E)
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, B and C for form, orientation and location.

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 specifications made in accordance with this

document, unless otherwise indicated.

For more detailed information of the relation of this document to the GPS matrix model, see Annex F.

ISO 1101 and other relevant documents, such as those dealing with the least and maximum material

requirement (ISO 2692) and the datum system (ISO 5459), should be taken into consideration when

using this document.

This document provides rules for the tolerancing of a tolerance zone pattern, i.e. a collection of tolerance

zones constrained to each other with or without reference to a datum system which does not lock all

degrees of freedom.
For the presentation of lettering (proportions and dimensions), see ISO 3098-2.

All figures in this document for the 2D drawing indications have been drawn in first-angle projection

with dimensions and tolerances in millimeters. It should be understood that third-angle projection

and other units of measurement could have been used equally well without prejudice to the principles

established.

Annexes A and B provide more information on the changes in practice and differences between this

document and ISO 1101 on one hand and ISO 5458:1998 on the other hand.
© ISO 2018 – All rights reserved v
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SIST EN ISO 5458:2018
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SIST EN ISO 5458:2018
INTERNATIONAL STANDARD ISO 5458:2018(E)
Geometrical product specifications (GPS) — Geometrical
tolerancing — Pattern and combined geometrical
specification

IMPORTANT — The illustrations included in this document are intended to illustrate the text

and/or to provide examples of the related technical drawing specification; these illustrations

are not fully dimensioned and toleranced, showing only the relevant general principles.

In particular, many illustrations do not contain filter specifications. As a consequence, the

illustrations are not a representation of a complete workpiece, and are not of a quality that is

required for use in industry (in terms of full conformity with the standards prepared by ISO/

TC 10 and ISO/TC 213), and as such are not suitable for projection for teaching purposes.

1 Scope

This document establishes complementary rules to ISO 1101 to be applied to pattern specifications and

defines rules to combine individual specifications, for geometrical specifications e.g. using the symbols

POSITION, SYMMETRY, LINE PROFILE and SURFACE PROFILE, as well as STRAIGHTNESS (in the case

where the toleranced features are nominally coaxial) and FLATNESS (in the case where the toleranced

features are nominally coplanar) as listed in Annex C.

These rules apply when a set of tolerance zones are grouped together with location or orientation

constraints, through the use of the CZ, CZR or SIM modifiers.

This document does not cover the use of the pattern specifications when the least and maximum

material requirement is applied (see ISO 2692).

This document does not cover the establishment of common datum (see ISO 5459) based on pattern

features.
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 1101, Geometrical product specifications (GPS) — Geometrical tolerancing — Tolerances of form,

orientation, location and run-out

ISO 8015, Geometrical product specifications (GPS) — Fundamentals — Concepts, principles and rules

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

ISO 22432, Geometrical product specifications (GPS) — Features utilized in specification and verification

3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 8015, ISO 1101, ISO 17450-1,

ISO 17450-2, ISO 22432 and the following apply.
© ISO 2018 – All rights reserved 1
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SIST EN ISO 5458:2018
ISO 5458:2018(E)

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

— ISO Online browsing platform: available at https: //www .iso .org/obp
— IEC Electropedia: available at http: //www .electropedia .org/
3.1
pattern specification

combined requirement indicated by a set of geometrical specifications, and controlled by a tolerance

zone pattern

Note 1 to entry: The geometrical features controlled by a pattern specification can be a set of compound features,

united features or single features, which can be features of size (linear or angular).

Note 2 to entry: Annex C provides examples of pattern specifications in Table C.1.

Note 3 to entry: The set of pattern features controlled by a pattern specification does not define a united feature.

A united feature can be a pattern feature, i.e. one of the members of the toleranced features controlled by a

pattern specification.
3.2
pattern feature

geometrical feature which is a member of the set of features controlled by a pattern specification

3.3
tolerance zone pattern

combination of more than one tolerance zone, having, without priority between them, constraints of

orientation and location, or constraints of orientation

Note 1 to entry: A tolerance zone pattern is composed of several tolerance zones which can have different nominal

geometries.

Note 2 to entry: A tolerance zone pattern can be established without external constraint or with orientation

constraint and/or location constraint from a datum system.
3.4
pattern characteristic
geometrical characteristic controlled by a pattern specification
3.5
theoretical exact feature pattern
TEF pattern

combination of more than one TEF having, without priority between them, constraints of orientation

and location, or constraints of orientation, used to establish the pattern characteristic

Note 1 to entry: A TEF pattern is composed of several TEFs which can have different nominal geometries and

constrained between them, with respect to their relative location and/or orientation.

Note 2 to entry: A TEF pattern can be established without external constraint or with orientation constraint

and/or location constraint from a datum system.
3.6
single indicator pattern specification
pattern specification, controlled by one tolerance indicator specification
3.7
multiple indicator pattern specification

pattern specification, controlled by more than one tolerance indicator specification

3.8
multi-level single indicator pattern specification

single indicator pattern specification applied to more than one group of toleranced features

2 © ISO 2018 – All rights reserved
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SIST EN ISO 5458:2018
ISO 5458:2018(E)
3.9
internal constraint

location constraint and/or orientation constraint between the individual tolerance zones of the

tolerance zone pattern
3.10
external constraint

location constraint and/or orientation constraint between a tolerance zone or tolerance zone pattern

and a datum system
4 Symbols and specification modifiers

For the purposes of this document, the specification modifiers of Table 1 shall apply.

Rules for the presentation of graphical symbols shall be in accordance with Annex D.

Table 1 — Specification modifiers
Applied to Symbol Description Internal constraint Modifier defined in
Toleranced
UF United feature Not applicable ISO 1101
feature
SZ Separate zones None 5.1
Simultaneous require- Orientation and location
a,b
SIMi 5.4.4
ment No. i constraints
Tolerance zones
CZ Combined zone Orientation and location 5.4.3, 5.4.5 and ISO 1101
Combined zone rota-
CZR Orientation constraint only 5.4.3 and 5.4.5
tional only

An identification number i can be associated to the modifier SIM. In this case there is no space between SIM and i.

“SIM” in ISO 8785 is used for a family of “surface imperfection” parameters with indices (e.g. a, n, t, w, cd, ch, sh, n/A).

The modifier simultaneous requirement (SIM) as indicated in this document shall not be confused with the indication of a

surface imperfection parameter (e.g. SIM1 versus SIMt).
5 Principles
5.1 General

According to the feature principle (see ISO 8015:2011, 5.4), by default a geometrical specification

applies to one complete single feature as defined in ISO 22432. It is the designer’s responsibility to

select the features or portions of features to which a specification applies and either indicate that on a

2D drawing using appropriate symbology or define it in the CAD model.

According to the independency principle (see ISO 8015:2011, 5.5), by default a geometrical specification

that applies to more than one single feature applies to those features independently. The tolerance zones

defined by one tolerance indicator or by several tolerance indicators shall be considered independently

by default; this corresponds to the meaning of the modifier SZ. When the same geometrical specification

is applied to several toleranced features, for all geometrical specifications other than position

specifications, the indication of SZ modifier is redundant (see rule A for position specification, 5.3).

If it is required that the geometrical specification applies to the features simultaneously with some

constraint between the tolerance zones, it is the designer’s responsibility to either indicate this on a 2D

drawing or in the CAD model using appropriate pattern specifications.

In order to manage functional requirements for a set of features, they can be controlled simultaneously

by means of a pattern specification, using tolerance zone pattern modifiers CZ, CZR or SIMn.

The use of the concept of “simultaneous requirement” transforms a set of more than one geometrical

specification into a combined specification, i.e. a pattern specification.
© ISO 2018 – All rights reserved 3
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SIST EN ISO 5458:2018
ISO 5458:2018(E)

There are two ways to create a tolerance zone pattern, either by using a single indicator pattern

specification with the CZ or CZR modifiers [see Figure 1 a) and rules C and E] or by using a multiple

indicator pattern specification using SIM modifiers [see Figure 1 b) and rule D (5.4.4)].

a) Single indicator pattern specification b) Multiple indicator pattern specification

Figure 1 — Example of pattern specifications
5.2 Concepts

A pattern specification consists of both a set of more than one geometrical feature and a tolerance zone

pattern. The set of tolerance zones in the tolerance zone pattern have internal constraints, which are

defined by implicit or explicit TEDs.

If necessary, external constraints to a tolerance zone pattern can be defined by referencing a datum

system, as defined in ISO 5459. The values of external constraints are defined by implicit or explicit TEDs.

The main specification elements of a pattern specification are:

— the identification of a single indicator pattern specification or a multiple indicator pattern

specification;

— the internal constraint (in orientation and/or in location) between the individual tolerance zones of

the tolerance zone pattern defined by TEDs;

— the tolerance zone pattern defined as a collection of individual tolerance zones;

— if applicable, external constraints (in orientation and/or in location) of the tolerance zone pattern

defined by TEDs from a datum system, see ISO 5459.

There is no functional difference between using n identical specifications or a pattern specification

(with n members) when these specifications refer to a datum system which locks all degrees of freedom

of the related tolerance zones. However, there is a difference from a characteristic point of view: there

is only one pattern characteristic defined for a pattern specification, whereas there are n geometrical

characteristics defined each one for the n individual specifications.

There is a functional difference between using n identical specifications or a pattern specification (with

n members) when the pattern specification refers to a datum system which does not lock all degrees of

freedom of the related tolerance zones, or when the pattern specification does not refer to a datum system.

The rules, applied for pattern specification and their repetitions, are given in 5.3 and 5.4. A concept

diagram in Annex E illustrates these rules. Examples with their meanings are given in Annex C.

5.3 Rule A: for position specification

When a position specification is applied to several geometrical features and the tolerance zones have at

least one unlocked non-redundant degree of freedom, either the SZ or CZ or CZR modifier shall always

be indicated in the tolerance section, see Figure 2 and for former practice, see Annex A.

4 © ISO 2018 – All rights reserved
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SIST EN ISO 5458:2018
ISO 5458:2018(E)

Using the SZ modifier to a position specification without datum section makes the specification

meaningless.

NOTE This rule is in line with the independency principle stated in ISO 8015. However, ISO 5458:1998 was

in conflict with the independency principle, since a pattern specification without the CZ modifier implied that

the tolerance zones for the repeated specifications were related with internal constraints, and thus dependent

on each other (see Annex A and Annex B). Rule A (5.3), which includes the exception for position specification,

eliminates this conflict.

a) Pattern specification b) Not a pattern specification: Two c) Pattern specification

without a datum independent specifications with a datum
with a datum

Figure 2 — Example of geometrical specifications which are or are not pattern specification

5.4 Rules for pattern specification
5.4.1 General

To create a single indicator pattern specification, a geometrical specification shall be applied to a set

of more than one geometrical feature simultaneously. Internal constraints to define the tolerance zone

pattern between the individual tolerance zones shall be defined and, if necessary, external constraints

from a datum or datum system shall also be defined.

To create a multiple indicator pattern specification, a set of more than one separate geometrical

specification shall be applied to a set of more than one geometrical feature simultaneously. Internal

constraints to define the tolerance zone pattern between the individual tolerance zones shall be defined

and, if necessary, external constraints from a datum or datum system shall also be defined.

It is possible to indicate a repetition of an identical geometrical specification, as described in ISO 1101,

to control several geometrical features.
5.4.2 Rule B: constraints
A pattern specification defines internal constraints.

A pattern specification can define external constraints when the geometrical specification includes a

datum or datum system.

The internal constraints consist of the location constraints and/or the orientation constraints linking

the individual tolerance zones composing a tolerance zone pattern.

The external constraints define the location constraints and/or the orientation constraints linking the

tolerance zone pattern to a datum or datum system.

These internal or externals constraints are defined by TEDs, which can be explicit or implicit.

The following TEDs are i
...

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