EN ISO 18391:2016

SLOVENSKI STANDARD
01-januar-2017
6SHFLILNDFLMDJHRPHWULMVNLKYHOLþLQL]GHOND*363RSXODFLMVNDVSHFLILNDFLMD,62

Geometrical product specification (GPS) - Population specification (ISO 18391:2016)
Geometrische Produktspezifikation (GPS) - Populationsspezifikation (ISO 18391:2016)
Spécification géométrique des produits - Spécification de population (ISO 18391:2016)
Ta slovenski standard je istoveten z: EN ISO 18391:2016
ICS:
17.040.40 6SHFLILNDFLMDJHRPHWULMVNLK Geometrical Product
YHOLþLQL]GHOND*36 Specification (GPS)
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 18391
EUROPEAN STANDARD
NORME EUROPÉENNE
November 2016
EUROPÄISCHE NORM
ICS 17.040.40
English Version
Geometrical product specifications (GPS) - Population
specification (ISO 18391:2016)
Spécification géométrique des produits (GPS) - Geometrische Produktspezifikation (GPS) -
Spécification de population (ISO 18391:2016) Populationsspezifikation (ISO 18391:2016)
This European Standard was approved by CEN on 28 August 2016.

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, 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: Avenue Marnix 17, B-1000 Brussels
© 2016 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 18391:2016 E
worldwide for CEN national Members.

Contents Page
European foreword . 3
European foreword
This document (EN ISO 18391:2016) 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 May 2017, and conflicting national standards shall be
withdrawn at the latest by May 2017.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent
rights.
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, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.
Endorsement notice
The text of ISO 18391:2016 has been approved by CEN as EN ISO 18391:2016 without any modification.

INTERNATIONAL ISO
STANDARD 18391
First edition
2016-10-01
Geometrical product specifications
(GPS) — Population specification
Spécification géométrique des produits (GPS) — Spécification de
population
Reference number
ISO 18391:2016(E)
©
ISO 2016
ISO 18391:2016(E)
© ISO 2016, Published in Switzerland
All rights reserved. Unless otherwise specified, 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
Ch. de Blandonnet 8 • CP 401
CH-1214 Vernier, Geneva, Switzerland
Tel. +41 22 749 01 11
Fax +41 22 749 09 47
copyright@iso.org
www.iso.org
ii © ISO 2016 – All rights reserved

ISO 18391:2016(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Rules for establishing a population specification . 3
4.1 General . 3
4.2 Rules . 3
4.2.1 Rule 1: Description of a population specification. 3
4.2.2 Rule 2: Description of type of individual GPS specification (univariate
or multivariate) . 5
4.2.3 Rule 3 . 7
5 Symbol used to specify a population specification . 8
6 Rules for indicating a population specification .11
Annex A (informative) Relation in the GPS matrix model .15
Bibliography .16
ISO 18391:2016(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. 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. 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 meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO’s adherence to the WTO principles in the Technical
Barriers to Trade (TBT), see the following URL: Foreword - Supplementary information
The committee responsible for this document is ISO/TC 213, Dimensional and geometrical product
specifications and verification.
iv © ISO 2016 – All rights reserved

ISO 18391:2016(E)
Introduction
This International Standard is a Geometrical Product Specification (GPS) standard and is to be regarded
as a global GPS standard (see ISO 14638). It influences all chain links of all chains of standards.
The ISO/GPS Masterplan 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 on the relationship of this
International standard to other standards and to the GPS matrix model, see Annex A.
In order to define the permissible interval for a geometrical characteristic, the designer only defines
a condition (a unilateral tolerance limit or a bilateral pair of tolerance limits) for each workpiece, by
considering the worst case impact in an assembly.
But when the tolerancing is based on a set of hypotheses about the population of the workpieces, one or
more additional requirements should be added to verify these hypotheses.
NOTE The intent of this International Standard is not to define calculation methods to determine tolerances,
but to give the means to express the hypotheses to verify.
INTERNATIONAL STANDARD ISO 18391:2016(E)
Geometrical product specifications (GPS) — Population
specification
1 Scope
This International Standard defines rules to establish and to indicate population specifications, which
are used to specify conditions on population characteristics, which are established from a set of
characteristic values obtained one on each workpiece of a population of workpieces.
A population specification (as applied to a population of workpieces considered as a collection and
not as individual items) can be seen as a complementary requirement to the individual specification
(as applied to each workpiece considered as individual items). Population specifications express the
statistical hypotheses used on the population of workpieces.
NOTE 1 A population specification is a complement to an individual GPS specification.
NOTE 2 This International Standard is not intended to mandate a given tolerancing method or how to calculate
tolerance values. Its intent is to specify tools to allow the expression of population specifications.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. 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 14405-1, Geometrical product specifications (GPS) — Dimensional tolerancing — Part 1: Linear sizes
ISO 17450-1, Geometrical product specifications (GPS) — General concepts — Part 1: Model for geometrical
specification and verification
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 17450-1 and the following apply.
3.1
population characteristic
statistic defined from the characteristic values, obtained on the population of workpieces or the
population of assemblies
Note 1 to entry: Population characteristics are used to consider the population of workpieces.
Note 2 to entry: Population characteristics are only statistically meaningful when the values are based upon
global individual characteristics, see Example 2
...