EN 61078:2016
(Main)Reliability block diagrams
Reliability block diagrams
IEC 61078:2016 this International Standard describes: - the requirements to apply when reliability block diagrams (RBDs) are used in dependability analysis; - the procedures for modelling the dependability of a system with reliability block diagrams; - how to use RBDs for qualitative and quantitative analysis; - the procedures for using the RBD model to calculate availability, failure frequency and reliability measures for different types of systems with constant (or time dependent) probabilities of blocks success/failure, and for non-repaired blocks or repaired blocks; - some theoretical aspects and limitations in performing calculations for availability, failure frequency and reliability measures; - the relationships with fault tree analysis (see IEC 61025) and Markov techniques (see IEC 61165). This third edition cancels and replaces the second edition published in 2006. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition: - the structure of the document has been entirely reconsidered, the title modified and the content extended and improved to provide more information about availability, reliability and failure frequency calculations; - Clause 3 has been extended and clauses have been introduced to describe the electrical analogy, the "non-coherent" RBDs and the "dynamic" RBDs; - Annex B about Boolean algebra methods has been extended; - Annex C (Calculations of time dependent probabilities), Annex D (Importance factors), Annex E (RBD driven Petri net models) and Annex F (Numerical examples and curves) have been introduced. Keywords: reliability block diagram (RBD)
Zuverlässigkeitsblockdiagramme
Diagrammes de fiabilité
L'IEC 61078:2016 la présente Norme internationale décrit: - les exigences à appliquer lors de l'utilisation de diagrammes de fiabilité (BDF) dans le cadre d'analyses de sûreté de fonctionnement; - les procédures de modélisation de la sûreté de fonctionnement d'un système avec des diagrammes de fiabilité; - comment utiliser les BDF pour procéder à des analyses qualitatives et quantitatives; - les procédures d'utilisation du modèle BDF pour calculer les mesures de disponibilité, de fréquence de défaillance et de fiabilité pour différents types de systèmes avec des probabilités constantes (ou dépendant du temps) de succès/défaillance de blocs, et ceci pour des blocs non réparés ou des blocs réparés; - certains aspects et limitations théoriques liés aux calculs des mesures de disponibilité, de fréquence de défaillance et de fiabilité; - les relations avec l'analyse par arbre de panne (voir IEC 61025) et les techniques de Markov (voir IEC 61165). Cette troisième édition annule et remplace la deuxième édition publiée en 2006. Cette édition constitue une révision technique. Cette édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente: - la structure du document a été entièrement remaniée, le titre modifié et le contenu étendu et amélioré afin de fournir de plus amples informations sur les calculs de disponibilité, de fiabilité et de fréquence de défaillance; - l'Article 3 a été étendu et des articles ont été introduits pour décrire l'analogie électrique, les BDF "non cohérents" et les BDF "dynamiques"; - l'Annexe B relative aux méthodes algébriques booléennes a été étendue; - l'Annexe C (Calculs des probabilités en fonction du temps), l'Annexe D (Facteurs d'importance), l'Annexe E (Modèles de réseau de Petri piloté par BDF) et l'Annexe F (Exemples numériques et courbes) ont été introduites. Mots clés: diagrammes de fiabilité (BDF)
Zanesljivost, blokovni diagrami (IEC 61078:2016)
Ta mednarodni standard opisuje:
• zahteve, ki jih je treba izpolniti, ko se za analizo zagotovljivosti uporabljajo blokovni diagrami zanesljivosti (RBD);
• postopke za modeliranje zagotovljivosti sistema z blokovnimi diagrami zanesljivosti;
• uporabo blokovnih diagramov zanesljivosti za kvalitativne in kvantitativne analize;
• postopke za uporabo modela blokovnih diagramov zanesljivosti za izračun ukrepov razpoložljivosti, pogostosti odpovedi in zanesljivosti za različne vrste sistemov s konstantno (ali časovno odvisno)
verjetnostjo blokov uspeha/neuspeha ter za nepopravljene ali popravljene bloke;
• nekatere teoretske vidike in omejitve pri izvajanju izračunov za ukrepe razpoložljivosti, pogostosti odpovedi in zanesljivosti;
• odnose z analizo drevesa okvar (glejte standard IEC 61025 [1]) in Markove tehnike (glejte standard IEC 61165 [2]).
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
01-januar-2017
1DGRPHãþD
SIST EN 61078:2007
Zanesljivost, blokovni diagrami (IEC 61078:2016)
Reliability block diagrams (IEC 61078:2016)
Ta slovenski standard je istoveten z: EN 61078:2016
ICS:
03.120.01 Kakovost na splošno Quality in general
21.020 =QDþLOQRVWLLQQDþUWRYDQMH Characteristics and design of
VWURMHYDSDUDWRYRSUHPH machines, apparatus,
equipment
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EUROPEAN STANDARD EN 61078
NORME EUROPÉENNE
EUROPÄISCHE NORM
November 2016
ICS 03.120.01; 03.120.99 Supersedes EN 61078:2006
English Version
Reliability block diagrams
(IEC 61078:2016)
Diagrammes de fiabilité Zuverlässigkeitsblockdiagramme
(IEC 61078:2016) (IEC 61078:2016)
This European Standard was approved by CENELEC on 2016-09-16. 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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, 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: Avenue Marnix 17, B-1000 Brussels
© 2016 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN 61078:2016 E
European foreword
The text of document 56/1685/FDIS, future edition 3 of IEC 61078, prepared by
IEC/TC 56 "Dependability" was submitted to the IEC-CENELEC parallel vote and approved by
CENELEC as EN 61078:2016.
The following dates are fixed:
(dop) 2017-06-16
• latest date by which the document has to be
implemented at national level by
publication of an identical national
standard or by endorsement
• latest date by which the national (dow) 2019-09-16
standards conflicting with the
document have to be withdrawn
This document supersedes EN 61078:2006.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CENELEC [and/or CEN] shall not be held responsible for identifying any or all such
patent rights.
Endorsement notice
The text of the International Standard IEC 61078:2016 was approved by CENELEC as a European
Standard without any modification.
In the official version, for Bibliography, the following notes have to be added for the standards indicated:
IEC 61025 NOTE Harmonized as EN 61025.
IEC 61165 NOTE Harmonized as EN 61165.
IEC 62551 NOTE Harmonized as EN 62551.
IEC 60812 NOTE Harmonized as EN 60812.
IEC 61508:2010 Series NOTE Harmonized as EN 61508:2010 Series.
IEC 61511:2016 Series NOTE Harmonized as EN 61511:2016 Series.
ISO/TR 12489 NOTE Harmonized as CEN ISO/TR 12489.
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
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.
NOTE 1 When 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 - International Electrotechnical Vocabulary - - -
Part 192: Dependability
IEC 61703 - Mathematical expressions for reliability, EN 61703 -
availability, maintainability and
maintenance support terms
IEC 61078 ®
Edition 3.0 2016-08
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Reliability block diagrams
Diagrammes de fiabilité
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 03.120.01; 03.120.99 ISBN 978-2-8322-3561-4
– 2 – IEC 61078:2016 © IEC 2016
CONTENTS
FOREWORD . 8
INTRODUCTION . 10
1 Scope . 11
2 Normative references. 11
3 Terms and definitions . 11
4 Symbols and abbreviated terms . 18
5 Preliminary considerations, main assumptions, and limitations . 22
5.1 General considerations . 22
5.2 Pre-requisite/main assumptions . 23
5.3 Limitations . 23
6 Establishment of system success/failed states . 24
6.1 General considerations . 24
6.2 Detailed considerations . 24
6.2.1 System operation . 24
6.2.2 Environmental conditions . 25
6.2.3 Duty cycles . 25
7 Elementary models . 25
7.1 Developing the model . 25
7.2 Series structures . 25
7.3 Parallel structures . 26
7.4 Mix of series and parallel structures. 26
7.5 Other structures . 27
7.5.1 m out of n structures . 27
7.5.2 Structures with common blocks . 28
7.5.3 Composite blocks . 29
7.6 Large RBDs and use of transfer gates . 29
8 Qualitative analysis: minimal tie sets and minimal cut sets. . 30
8.1 Electrical analogy . 30
8.2 Series-parallel representation with minimal success path and cut sets . 32
8.3 Qualitative analysis from minimal cut sets . 33
9 Quantitative analysis: blocks with constant probability of failure/success . 33
9.1 Series structures . 33
9.2 Parallel structures . 34
9.3 Mix of series and parallel structures. 34
9.4 m/n architectures (identical items) . 35
10 Quantitative analysis: blocks with time dependent probabilities of failure/success . 35
10.1 General . 35
10.2 Non-repaired blocks . 36
10.2.1 General . 36
10.2.2 Simple non-repaired block . 36
10.2.3 Non-repaired composite blocks. 36
10.2.4 RBDs with non-repaired blocks . 37
10.3 Repaired blocks . 37
10.3.1 Availability calculations . 37
10.3.2 Average availability calculations . 40
IEC 61078:2016 © IEC 2016 – 3 –
10.3.3 Reliability calculations . 42
10.3.4 Frequency calculations . 43
11 Boolean techniques for quantitative analysis of large models . 43
11.1 General . 43
11.2 Method of RBD reduction . 44
11.3 Use of total probability theorem . 45
11.4 Use of Boolean truth tables . 46
11.5 Use of Karnaugh maps . 47
11.6 Use of the Shannon decomposition and binary decision diagrams . 49
11.7 Use of Sylvester-Poincaré formula . 50
11.8 Examples of RBD application. 51
11.8.1 Models with repeated blocks . 51
11.8.2 m out of n models (non-identical items) . 54
12 Extension of reliability block diagram techniques . 54
12.1 Non-coherent reliability block diagrams . 54
12.2 Dynamic reliability block diagrams . 57
12.2.1 General . 57
12.2.2 Local interactions . 58
12.2.3 Systemic dynamic interactions . 59
12.2.4 Graphical representations of dynamic interactions . 59
12.2.5 Probabilistic calculations . 62
Annex A (informative) Summary of formulae . 63
Annex B (informative) Boolean algebra methods . 67
B.1 Introductory remarks . 67
B.2 Notation . 67
B.3 Tie sets (success paths) and cut sets (failure paths) analysis . 68
B.3.1 Notion of cut and tie sets . 68
B.3.2 Series-parallel representation using minimal tie and cut sets . 69
B.3.3 Identification of minimal cuts and tie sets . 70
B.4 Principles of calculations .
...
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