1、BRITISH STANDARDBS EN 62308:2006Equipment reliability Reliability assessment methodsThe European Standard EN 62308:2006 has the status of a British StandardICS 03.120.01; 03.120.99g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36
2、g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58BS EN 62308:2006This British Standard was published under the authority of the Standards Policy and Strategy Committee on 30 March 2007 BSI 2007ISBN 978 0 580 50405 1National forewordThis British Standard was published b
3、y BSI. It is the UK implementation of EN 62308:2006. It is identical with IEC 62308:2006.The UK participation in its preparation was entrusted by Technical Committee DS/1, Dependability and terotechnology, to Subcommittee DS/1/1, Dependability.A list of organizations represented on DS/1/1 can be obt
4、ained on request to its secretary.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application.Compliance with a British Standard cannot confer immunity from legal obligations.Amendments issued since publicationAmd. No. Da
5、te CommentsEUROPEAN STANDARD EN 62308 NORME EUROPENNE EUROPISCHE NORM December 2006 CENELEC European Committee for Electrotechnical Standardization Comit Europen de Normalisation Electrotechnique Europisches Komitee fr Elektrotechnische Normung Central Secretariat: rue de Stassart 35, B - 1050 Bruss
6、els 2006 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members. Ref. No. EN 62308:2006 E ICS 03.120.01; 03.120.99 English version Equipment reliability - Reliability assessment methods (IEC 62308:2006) Fiabilit de lquipement - Mthodes dvaluation de
7、la fiabilit (CEI 62308:2006) Zuverlssigkeit von Gerten - Verfahren zur Zuverlssigkeitsbewertung (IEC 62308:2006) This European Standard was approved by CENELEC on 2006-11-01. CENELEC members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
8、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 Central Secretariat or to any CENELEC member. This European Standard exists in three official versions
9、(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 Central Secretariat has the same status as the official versions. CENELEC members are the national electrotechnical committees of Aust
10、ria, Belgium, Cyprus, the Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. Foreword Th
11、e text of document 56/1110/FDIS, future edition 1 of IEC 62308, prepared by IEC TC 56, Dependability, was submitted to the IEC-CENELEC parallel vote and was approved by CENELEC as EN 62308 on 2006-11-01. The following dates were fixed: latest date by which the EN has to be implemented at national le
12、vel by publication of an identical national standard or by endorsement (dop) 2007-08-01 latest date by which the national standards conflicting with the EN have to be withdrawn (dow) 2009-11-01 Annex ZA has been added by CENELEC. _ Endorsement notice The text of the International Standard IEC 62308:
13、2006 was approved by CENELEC as a European Standard without any modification. _ EN 62308:2006 2 CONTENTS INTRODUCTION. 5 1 Scope. 6 2 Normative references . 6 3 Terms and definitions . 7 4 Abbreviations . 8 5 Symbols . 8 6 Introduction to reliability assessment 9 6.1 Introductory remarks . 9 6.2 Des
14、cription of reliability assessment 9 7 Management of reliability assessment process .13 7.1 Purpose of reliability assessment 13 7.2 Documentation 19 8 Data needs.19 8.1 Input data19 8.2 Data sources and types.20 8.3 Data collection, storage, and retrieval .21 9 Reliability assessment methods21 9.1
15、Introduction .21 9.2 Similarity analysis .23 9.3 Durability analysis .25 9.4 Sensitivity testing and analysis26 9.5 Handbook predictions28 9.6 Limitations of reliability assessment results .30 10 Considerations for selecting reliability assessment methods.30 11 Reliability assessment process improve
16、ment32 11.1 General .32 11.2 Validating reliability assessment results 32 11.3 Improving the reliability assessment process.32 Annex A (informative) Similarity analysis examples.34 Annex B (informative) Durability analysis 46 Bibliography53 Figure 1 Methods requiring a reliability assessment as inpu
17、t13 Figure 2 Stages of product life cycle 17 Figure 3 Reliability assessment and improvement process.22 Figure A.1 Example similarity analysis flowchart 42 EN 62308:2006 3 Annex ZA (normative) Normative references to international publications with their corresponding European publications 57 Table
18、1 Example of constant rate reliability measures11 Table 2 IEC Standards providing guidance on methods .14 Table A.1 Example characteristic differences.41 Table A.2 Example high-level similarity analysis spreadsheet 43 Table A.3 Example low-level similarity analysis spreadsheet44 Table A.4 Example pr
19、ocess difference factor tables.45 Table B.1 Values for exponent B for equations (B.7) and (B.8).50 EN 62308:2006 4 INTRODUCTION This International Standard describes procedures that are intended for use in assessing the reliability of items based on data from: the market of similar items; and field
20、data and test data from suppliers of components and modules. The results of such assessments are intended for use as inputs to early equipment design decisions such as system architecture selection as well as business decisions such as estimating the cost of warranties or maintenance cost guarantees
21、. Furthermore the results can be used as the initial estimate for input to safety analysis, for example FTA analysis. Modern electronic components and items are so reliable that estimating or verifying their reliability by testing is very difficult, therefore data from the field for previous similar
22、 items are often the only way to get an initial estimate of the reliability. Component manufacturers have used this method for years under the name of the “similarity principle”. By emphasising the use of data from previously marketed similar products, and requiring similarity to be documented, the
23、method is a modern alternative to the classical but now obsolete handbook prediction. Reliability assessment results should be viewed as an early estimate of the probability that the product reliability targets and goals can be satisfied using the chosen architecture, modules, components and mainten
24、ance policy. As such, they may be used, for example, to authorize advancement to the next step in product development, or to authorize progress payments, or to proceed with delivery and acceptance of products. Reliability assessment results should never be used to support a claim that the reliabilit
25、y targets, goals, or expectations have been satisfied. The only certain measure of reliability requirement having been met is from service/field performance. This standard describes the uses for reliability assessment results as well as providing a list of IEC standards that require such results as
26、input. The approach to reliability assessment in this International Standard encourages the equipment manufacturer to consider all relevant information regarding equipment reliability which may include the effects of design and manufacturing processes as well as component selection issues. This is i
27、n contrast to more traditional methods that focus on component reliability as the most significant contributor to the equipment reliability; encourages the equipment manufacturer to define and use the processes that are most effective for the manufacturers own equipment; describes a continuous proce
28、dure in which a reliability assessment can be updated as more information becomes available during the life cycle of the equipment. This information may be used to improve both the reliability of the equipment and the effectiveness of the assessment process. This International Standard describes the
29、 application of three approaches to reliability assessment, namely: similarity analysis, durability analysis, and handbook predictions. This standard does not, however, provide information on assessing the reliability of software systems but can be used for assessing the reliability of hardware syst
30、ems containing embedded software. EN 62308:2006 5 EQUIPMENT RELIABILITY RELIABILITY ASSESSMENT METHODS 1 Scope This International Standard describes early reliability assessment methods for items based on field data and test data for components and modules. It is applicable to mission, safety and bu
31、siness critical, high integrity and complex items. It contains information on why early reliability estimates are required and how and where the assessment would be used. Finally, it details methods for reliability assessment and the data required to support the assessment. To estimate durability (l
32、ife time or wear-out), the physics-of-failure method is used. Three types of assessment are discussed in detail: the similarity approach; models for durability analysis; handbook methods. Clause 6 provides an introduction to reliability assessment and Clause 7 the management of the process. Clause 8
33、 describes the data needs, sources and types for assessments and Clause 9 provides details of the assessment methods. Annexes A and B provide additional information to aid understanding of the similarity analysis and durability analysis. This standard is applicable to making reliability estimates fo
34、r specifications, design, design modification and support engineering. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced
35、document (including any amendments) applies. IEC 60050-191:1990, International Electrotechnical Vocabulary Chapter 191: Dependability and quality of service IEC 60300-1, Dependability management Part 1: Dependability management systems IEC 60300-3-1:2003, Dependability management Part 3-1: Applicati
36、on guide Analysis techniques for dependability Guide on methodology IEC 60300-3-2, Dependability management Part 3-2: Application guide Collection of dependability data from the field IEC 60300-3-3, Dependability management Part 3-3: Application guide Life cycle costing IEC 60300-3-4:1996, Dependabi
37、lity management Part 3: Application guide Section 4: Guide to the specification of dependability requirements EN 62308:2006 6 IEC 60300-3-5:2001, Dependability management Part 3-5: Application guide Reliability test conditions and statistical test principles IEC 60300-3-9, Dependability management P
38、art 3: Application guide Section 9: Risk analysis of technological systems IEC 60300-3-11, Dependability management Part 3-11: Application guide Reliability centred maintenance IEC 60300-3-12, Dependability management Part 3-12: Application guide Integrated logistic support IEC 60812, Analysis techn
39、iques for system reliability Procedure for failure mode and effects analysis (FMEA) IEC 61025, Fault tree analysis (FTA) IEC 61078, Analysis techniques for dependability Reliability block diagram and boolean methods IEC 61160, Design review IEC 61165, Application of Markov techniques IEC 61508 (all
40、parts), Functional safety of electrical/electronic/programmable electronic safety-related systems IEC 61649, Goodness-of-fit tests, confidence intervals and lower confidence limits for Weibull distributed data IEC 61709, Electronic components Reliability Reference conditions for failure rates and st
41、ress models for conversion IECI 61710, Power law model Goodness-of-fit tests and estimation methods IEC 61713, Software dependability through the software life-cycle processes Application guide IEC 61882, Hazard and operability studies (HAZOP studies) Application guide IEC 62380, Reliability data ha
42、ndbook Universal model for reliability prediction of electronics components, PCBs and equipment 3 Terms and definitions For the purposes of this document, the terms and definitions given in IEC 60050-191, together with the following, apply. 3.1 durability analysis analysis of the equipments response
43、s to the stresses imposed by operational use, maintenance, shipping, storage and other activities throughout its specified life-cycle in order to estimate its predicted reliability and expected life 3.2 life-cycle time interval between a products conception and its disposal EN 62308:2006 7 3.3 simil
44、arity analysis structured comparison of the elements of the equipment being assessed with those of predecessor equipment for which in-service reliability data are available 4 Abbreviations ASIC Application specific integrated circuit BITE Built in test equipment COTS Commercial off the shelf FEA Fin
45、ite element analysis FFOP Failure free operating period FITS Failure per thousand million hours FMEA Failure mode and effects analysis FMECA Failure mode, effects and criticality analysis FRACAS Failure reporting, analysis and corrective action system FTA Fault tree analysis HALT Highly accelerated
46、life test IC Integrated circuit LCC Life cycle costs LRU Line replaceable unit MCTF Mean cycles to failure MTBF Mean time between failures MTBUR Mean time between unit repair MTTF Mean time to failure MTTR Mean time to restoration/recovery/repair MTTSC Mean time to service call MTTSI Mean time to se
47、rvice interruption MTTWC Mean time to warranty claim RBD Reliability block diagram RCM Reliability centred maintenance RET Reliability enhancement test SRU Shop replaceable unit 5 Symbols Constant failure rate of the exponential distribution t Time period of interest f(t) Probability density functio
48、n F(t) Cumulative distribution function R(t) Reliability function T* Accumulated exposure time EN 62308:2006 8 6 Introduction to reliability assessment 6.1 Introductory remarks The reliability of an item will often have to be assessed for a range of reasons including the following: a) setting target
49、s and specifications; b) comparing options; c) identifying and prioritising problems; d) indicating fitness for purpose; e) optimizing support (e.g. spares); f) to give input to other analysis (e.g. safety analysis); g) to prioritise areas for improvement with the greatest cost-effectiveness improvement potential. This reliability may be quoted in a number of ways, including for example accumulated percentage of failures; call rate; proba
