EN IEC 61123:2020
(Main)Reliability testing - Compliance test plans for success ratio
Reliability testing - Compliance test plans for success ratio
IEC 61123:2019 is intended to define a procedure to verify if a reliability of an item/system complies with the stated requirements. The requirement is assumed to be specified as the percentage of success (success ratio) or the percentage of failures (failure ratio). This document can be used where a number of items are tested (number of trials performed) and classified as passed or failed. It can also be used where one or a number of items are tested repeatedly. The procedures are based on the assumption that the probability of success or failure is the same from trial to trial (statistically independent events). Plans for fixed trial/failure terminated tests as well as truncated sequential probability ratio tests (SPRTs) are included. This document contains extensive tables with ready-to-use SPRT plans and their characteristics for equal and non-equal risks for supplier and customer. In the case of the reliability compliance tests for constant failure rate/intensity, IEC 61124 applies. This second edition cancels and replaces the first edition published in 1991. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition: The sequential probability ratio test (SPRT) [1, 2][1] has been significantly developed in recent years [3, 4, 5]. This edition contains shorter and accurate tests, a wide range of test plans, and significant additional characteristic data, as follows: the tests are significantly truncated (the maximum trial numbers are low) without substantially increasing the expected number of trials to decision (ENT); the true producer’s and consumer’s risks (α', β') are given and very close to the nominal (α, β); the range of the test parameters is wide (failure ratio, risks and discrimination ratio); the test plans include various risk ratios (not restricted to equal risks only); the values of ENT are accurate and given in the relevant region (for practical use); guidelines for extension of the test sets (interpolation and extrapolation) are included. In Annex C, the use of the cumulative binomial distribution function of Excel that simplifies the procedure of designing has been added (Clause C.3). Keywords: verify if a reliability of an item/system complies with the stated requirements
Prüfung der Zuverlässigkeit - Konformitätsprüfpläne für den Erfolgsquotienten
Essais de fiabilité - Plans d'essai de conformité pour une proportion de succès
IEC 61123:2019 vise à définir une procédure pour vérifier si la fiabilité d'une entité/d'un système satisfait aux exigences spécifiées. L'exigence est admise comme étant spécifiée sous forme de pourcentage de succès (proportion de succès) ou de pourcentage de défaillances (proportion de défaillances). Le présent document peut être utilisé lorsqu'un certain nombre d'entités sont soumises à l'essai (nombre d'épreuves réalisées) et classées comme ayant satisfait ou échoué à l'essai. Il peut également être utilisé lorsqu'une ou plusieurs entités sont soumises à l'essai de façon répétée. Les procédures sont fondées sur l'hypothèse que la probabilité de succès ou de défaillance est identique d'une épreuve à l'autre (événements statistiquement indépendants). Le présent document inclut des plans d'essais à nombre fixé d'épreuves et de défaillances, ainsi que des essais de rapport de probabilité progressifs (SPRT). Il contient des tableaux complets décrivant des plans de SPRT prêts à l'emploi et leurs caractéristiques associées, les risques pour le fournisseur et le client étant égaux ou non. Dans le cas d'essais de conformité de fiabilité relatifs à un taux/une intensité constant(e) de défaillance, l'IEC 61124 s'applique. Cette deuxième édition annule et remplace la première édition parue en 1991. Cette édition constitue une révision technique. Cette édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente: les essais sont considérablement tronqués (le nombre maximal d'épreuves est faible) sans pour autant augmenter substantiellement le nombre prévu d'épreuves pour décision (ENT – expected number of trials); les risques vrais du fournisseur et du client (α', β') sont connus et très proches des valeurs nominales (α, β); la plage des paramètres d'essai est étendue (proportion de défaillance, risques et rapport de discrimination); les plans d'essai intègrent différents rapports de risque (qui ne se limitent pas uniquement à des risques égaux); les valeurs de l'ENT sont précises et données dans la région pertinente (à des fins d'utilisation pratique); des lignes directrices sont fournies en vue d'étendre les séries d'essais (interpolation et extrapolation); en Annexe C, l'utilisation de la fonction de distribution binomiale cumulative d'Excel pour simplifier la procédure de calcul a été ajoutée (Article C.3). Mots clés: vérifier si la fiabilité d'une entité/d'un système satisfait aux exigences spécifiées
Preskušanje zanesljivosti - Načrti za preverjanje skladnosti z določeno stopnjo uspešnosti (IEC 61123:2019)
General Information
Standards Content (Sample)
SLOVENSKI STANDARD
01-maj-2020
Preskušanje zanesljivosti - Načrti za preverjanje skladnosti z določeno stopnjo
uspešnosti (IEC 61123:2019)
Reliability testing - Compliance test plans for success ratio (IEC 61123:2019)
Prüfung der Zuverlässigkeit - Konformitätsprüfpläne für den Erfolgsquotienten (IEC
61123:2019)
Essai de fiabilité - Plans d'essai de conformité pour une proportion de succès (IEC
61123:2019)
Ta slovenski standard je istoveten z: EN IEC 61123:2020
ICS:
03.120.01 Kakovost na splošno Quality in general
21.020 Značilnosti in načrtovanje Characteristics and design of
strojev, aparatov, opreme machines, apparatus,
equipment
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EUROPEAN STANDARD EN IEC 61123
NORME EUROPÉENNE
EUROPÄISCHE NORM
February 2020
ICS 03.120.01; 03.120.30; 21.020
English Version
Reliability testing - Compliance test plans for success ratio
(IEC 61123:2019)
Essais de fiabilité - Plans d'essai de conformité pour une Prüfung der Zuverlässigkeit - Konformitätsprüfpläne für den
proportion de succès Erfolgsquotienten
(IEC 61123:2019) (IEC 61123:2019)
This European Standard was approved by CENELEC on 2019-12-27. CENELEC 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 CENELEC 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 CENELEC member into its own language and notified to the CEN-CENELEC Management Centre has the
same status as the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic,
Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the
Netherlands, Norway, Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2020 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN IEC 61123:2020 E
European foreword
The text of document 56/1852/FDIS, future edition 2 of IEC 61123, prepared by IEC/TC 56
"Dependability" was submitted to the IEC-CENELEC parallel vote and approved by CENELEC as
The following dates are fixed:
• latest date by which the document has to be implemented at national (dop) 2020-09-27
level by publication of an identical national standard or by endorsement
• latest date by which the national standards conflicting with the (dow) 2022-12-27
document have to be withdrawn
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CENELEC shall not be held responsible for identifying any or all such patent rights.
Endorsement notice
The text of the International Standard IEC 61123:2019 was approved by CENELEC as a European
Standard without any modification.
In the official version, for Bibliography, the following note has to be added for the standard indicated:
IEC 61124 NOTE Harmonized as EN 61124
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
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.
NOTE 1 Where an International Publication has been modified by common modifications, indicated by (mod), the relevant
EN/HD applies.
NOTE 2 Up-to-date information on the latest versions of the European Standards listed in this annex is available here:
www.cenelec.eu.
Publication Year Title EN/HD Year
IEC 60050-192 2015 International electrotechnical vocabulary - - -
Part 192: Dependability
IEC 60300-3-5 2001 Dependability management - Part 3-5: - -
Application guide - Reliability test
conditions and statistical test principles
IEC 61123 ®
Edition 2.0 2019-11
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Reliability testing – Compliance test plans for success ratio
Essais de fiabilité – Plans d'essai de conformité pour une proportion de succès
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 03.120.01; 03.120.30; 21.020 ISBN 978-2-8322-7647-1
– 2 – IEC 61123:2019 © IEC 2019
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 8
2 Normative references . 8
3 Terms, definitions, abbreviated terms and symbols . 8
3.1 Terms and definitions . 8
3.2 Abbreviated terms and symbols . 9
3.2.1 Abbreviated terms . 9
3.2.2 Symbols . 9
4 General requirements and area of application . 10
4.1 Reliability requirement . 10
4.2 Repair and replacement . 10
4.3 Types of test plans . 10
4.3.1 General . 10
4.3.2 Features of the test plan types. 10
4.4 General test procedure . 11
4.5 General decision criteria . 11
5 Truncated sequential probability ratio test plans (SPRT) . 13
5.1 Characteristics . 13
5.2 Decision criteria . 13
5.3 Operating characteristic curve (OC) . 14
5.4 Expected number of trials to decision (ENT) . 15
6 Fixed trial/failure terminated test plans (FTFT) . 16
6.1 Characteristics . 16
6.2 Decision criteria . 16
7 Design of fixed trial/failure terminated test plans . 17
7.1 Characteristics . 17
7.2 Approach . 17
7.3 Common case . 18
7.4 Other cases . 18
7.5 Example of application . 18
7.6 Procedure to determine D and c or n and c . 18
7.6.1 Figure and table readings . 18
7.6.2 Use of figures and tables . 19
7.7 Decision criteria . 19
Annex A (informative) Additional information on sequential test plans . 20
A.1 Example. 20
A.2 Extension of the test set (through interpolation and extrapolation) . 21
A.2.1 General . 21
A.2.2 Extrapolation for p < 0,001 . 21
A.2.3 Interpolation . 21
Annex B (informative) Design of fixed trial/failure terminated test plans − Examples . 24
B.1 Use of figures and tables . 24
B.2 Case where number of events, n, is not known, but is predictable . 24
Annex C (informative) Design of fixed trial/failure terminated test plans – Mathematical
procedures and formulas . 26
IEC 61123:2019 © IEC 2019 – 3 –
C.1 General . 26
C.2 Symbols . 26
C.3 Computation . 26
C.3.1 Determination of D versus n . 26
C.3.2 Determination of n and c versus p , D, α, β . 27
C.3.3 Test without failures – Determination of n and D versus p , α, β . 27
C.3.4 Determination of OC curves . 28
C.3.5 Determination of inverse OC curves . 28
C.4 Accuracy . 29
C.5 Tables of cumulative normal distribution and its Inverse. 29
Annex D (normative) Truncated sequential test plans . 31
Annex E (informative) Design of fixed trial/failure terminated test plans – Figures and
tables to determine D and c or n and c . 40
Bibliography . 49
Figure 1 – Expected and maximal number of trials for SPRT and FTFT with the same risks . 11
Figure 2 – SPRT diagram. 14
Figure 3 – OC curve. 15
Figure 4 – SPRT – Curve of expected number of trials to decision (ENT) . 15
Figure 5 – Principal layout of Tables E.1 to E.3 . 19
Figure A.1 – Example of a truncated sequential test . 20
Figure E.1 – Discrimination ratio, D, versus number of events, n for p = 0,05 . 40
Figure E.2 – Discrimination ratio, D, versus number of events, n for p = 0,10 . 41
Figure E.3 – Discrimination ratio, D, versus number of events, n for p = 0,15 . 42
Table 1 – Overview – Maximal number of trials and expected number of trials at p for
SPRT and FTFT . 12
Table 2 – Range of the test parameters . 13
Table 3 – OC
...
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