1、 ISO 2013 Petroleum, petrochemical and natural gas industries Reliability modelling and calculation of safety systems Ptrole, ptrochimie et gaz naturel Modlisation et calcul fiabilistes des systmes de scurit TECHNICAL REPORT ISO/TR 12489 First edition 2013-11-01 Reference number ISO/TR 12489:2013(E)
2、 ISO/TR 12489:2013(E)ii ISO 2013 All rights reserved COPYRIGHT PROTECTED DOCUMENT ISO 2013 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
3、 the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below or ISOs member body in the country of the requester. ISO copyright office Case postale 56 CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyrightis
4、o.org Web www.iso.org Published in Switzerland ISO/TR 12489:2013(E) ISO 2013 All rights reserved iii Contents Page Foreword v Introduction vi 1 Scope . 1 2 Analysis framework . 2 2.1 Users of this Technical Report . 2 2.2 ISO/TR 12489 with regard to risk and reliability analysis processes . 2 2.3 Ov
5、erview of the reliability modelling and calculation approaches considered in this Technical Report 4 2.4 Safety systems and safety functions . 7 3 T erms and definitions . 8 3.1 Basic reliability concepts . 8 3.2 Failure classification20 3.3 Safety systems typology .24 3.4 Maintenance issues 25 3.5
6、Other terms .28 3.6 Equipment-related terms .29 4 Symbols and abbreviated terms 30 5 Overview and challenges 33 5.1 General considerations about modelling and calculation challenges 33 5.2 Deterministic versus probabilistic approaches .35 5.3 Safe failure and design philosophy .35 5.4 Dependent fail
7、ures .36 5.5 Human factors 37 5.6 Documentation of underlying assumptions .40 6 Introduction to modelling and calculations41 6.1 Generalities about safety systems operating in “on demand” or “continuous” modes .41 6.2 Analytical approaches 44 7 Analytical formulae approach (low demand mode) .47 7.1
8、Introduction .47 7.2 Underlying hypothesis and main assumptions 47 7.3 Single failure analysis .48 7.4 Double failure analysis 50 7.5 Triple failure analysis .55 7.6 Common cause failures .56 7.7 Example of implementation of analytical formulae: the PDS method .57 7.8 Conclusion about analytical for
9、mulae approach 57 8 Boolean and sequential approaches .58 8.1 Introduction .58 8.2 Reliability block diagrams (RBD) .58 8.3 Fault Tree Analysis (FTA) 59 8.4 Sequence modelling: cause consequence diagrams, event tree analysis, LOPA 61 8.5 Calculations with Boolean models 61 8.6 Conclusion about the B
10、oolean approach .64 9 Markovian approach .65 9.1 Introduction and principles 65 9.2 Multiphase Markov models .68 9.3 Conclusion about the Markovian approach 69 10 Petri net approach .69 10.1 Basic principle 69 10.2 RBD driven Petri net modelling .71 ISO/TR 12489:2013(E)iv ISO 2013 All rights reserve
11、d 10.3 Conclusion about Petri net approach .74 11 Monte Carlo simulation approach .74 12 Numerical reliability data uncertainty handling .74 13 Reliability data considerations 75 13.1 Introduction .75 13.2 Reliability data sources.76 13.3 Required reliability data 78 13.4 Reliability data collection
12、 .80 14 Typical applications .80 14.1 Introduction .80 14.2 Typical application TA1: single channel .82 14.3 Typical application TA2: dual channel .97 14.4 Typical application TA3: popular redundant architecture 110 14.5 Typical application TA4: multiple safety system .119 14.6 Typical application T
13、A5: emergency depressurization system (EDP) 124 14.7 Conclusion about typical applications 135 Annex A (informative) Systems with safety functions .136 Annex B (informative) Stat e anal y sis and failur e classification 146 Annex C (informative) Relationship between failure rate, conditional and unc
14、onditional failure intensities and failure frequency .152 Annex D (informative) Broad models for demand mode (reactive) safety systems 160 Annex E (informative) Continuous mode (preventive) safety systems 167 Annex F (informative) Multi-layers safety systems/multiple safety systems .170 Annex G (inf
15、ormative) Common cause failures 173 Annex H (informative) The human factor 180 Annex I (informative) Analytical formulae .186 Annex J (informative) Sequential modelling .207 Annex K (informative) Overview of calculations with Boolean models213 Annex L (informative) Markovian approach .221 Annex M (i
16、nformative) Petri net modelling239 Annex N (informative) Monte Carlo simulation approach 248 Annex O (informative) Numerical uncertainties handling .252 Bibliography .255 ISO/TR 12489:2013(E) Foreword ISO (the International Organization for Standardization) is a worldwide federation of national stan
17、dards 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 org
18、anizations, 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 it
19、s 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/di
20、rectives). 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
21、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 meaning of ISO specific terms and expressions re
22、lated to conformity assessment, as well as information about ISOs 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 67, Materials, equipment and offshore structure
23、s for petroleum, petrochemical and natural gas industries. This first edition of ISO/TR 12489 belongs of the family of reliability related standards developed by ISO/TC 67: ISO 14224, Petroleum, petrochemical and natural gas industries Collection and exchange of reliability and maintenance data for
24、equipment ISO 20815, Petroleum, petrochemical and natural gas industries Production assurance and reliability management ISO 2013 All rights reserved v ISO/TR 12489:2013(E) Introduction Safety systems have a vital function in petroleum, petrochemical and natural gas industries where safety systems r
25、ange from simple mechanical safety devices to safety instrumented systems. They share three important characteristics which make them difficult to handle: 1) They should be designed to achieve good balance between safety and production. This implies a high probability of performing the safety action
26、 as well as a low frequency of spurious actions. 2) Some of their failures are not revealed until relevant periodic tests are performed to detect and repair them. 3) A given safety system rarely works alone. It generally belongs to a set of several safety systems (so- called multiple safety systems)
27、 working together to prevent accidents. Therefore improving safety may be detrimental to dependability and vice versa. These two aspects should therefore, ideally, be handled at the same time by the same reliability engineers. However, in reality they are generally considered separately and handled
28、by different persons belonging to different departments. Moreover this is encouraged by the international safety standards, which exclude dependability from their scopes, and the international dependability (see 3.1.1) standard, which excludes safety from theirs. This may lead to dangerous situation
29、s (e.g. safety system disconnected because of too many spurious trips) as well as high production losses. The proof of the conservativeness of probabilistic calculations of safety systems is generally required by safety authorities. Unfortunately, managing the systemic dependencies introduced by the
30、 periodic tests to obtain conservative results implies mathematical difficulties which are frequently ignored. The impact is particularly noticeable for redundant safety systems and multiple safety systems. Awareness of these challenges is important for reliability engineers as well as safety manage
31、rs and decision makers, utilizing reliability analytical support. Most of the methods and tools presently applied in reliability engineering have been developed since the 1950s before the emergence of personal computers when only pencil and paper were available. At that time the reliability pioneers
32、 could only manage simplified models and calculations but this has completely changed because of the tremendous improvement in the computation means achieved over the past 30 years. Nowadays, models and calculations which were once impossible are carried out with a simple laptop computer. Flexible (
33、graphical) models and powerful algorithms based on sound mathematics are now available to handle “industrial size” systems (i.e. many components with complex interactions). This allows the users to focus on the analysis of the systems and assessment of results, rather than on the calculations themse
34、lves. All the approaches described in this Technical Report have been introduced in the petroleum, petrochemical and natural gas industries as early as the 1970s where they have proven to be very effective. They constitute the present time state-of-the-art in reliability calculations. Nevertheless s
35、ome of them have not been widely disseminated in this sector although they can be of great help for reliability engineers to overcome the problems mentioned above. This is particularly true when quantitative reliability or availability requirements need confirmation and/or when the objective of the
36、reliability study lay beyond the scope of the elementary approaches. The present document is a “technical” report and its content is obviously “technical”. Nevertheless, it only requires a basic knowledge in probabilistic calculation and mathematics and any skilled reliability engineer should have n
37、o difficulties in using it.vi ISO 2013 All rights reserved TECHNICAL REPORT ISO/TR 12489:2013(E) Petroleum, petrochemical and natural gas industries Reliability modelling and calculation of safety systems 1 Scope T h i s Tech n ic a l Repor t a i m s t o close t he g ap bet we en t he s t at e - of-
38、t he -a r t a nd t he appl ic at ion of pr obabi l i s t ic calculations for the safety systems of the petroleum, petrochemical and natural gas industries. It provides guidelines for reliability and safety system analysts and the oil and gas industries to: understand the correct meaning of the defin
39、itions used in the reliability field; identify the safety systems which may be concerned, the difficulties encountered when dealing with reliability modelling and calculation of safety systems, the relevant probabilistic parameters to be considered; be informed of effective solutions overcoming the
40、encountered difficulties and allowing to undertake the calculations of relevant probabilistic parameters; obtain sufficient knowledge of the principles and framework (e.g. the modelling power and limitations) of the well-established approaches currently used in the reliability field: analytical form
41、ulae; 1213 Boolean: reliability block diagrams; 4 fault trees; 5 sequential: event trees, 8cause consequence diagrams 10and LOPA; 9 Markovian; 6 Petri nets; 7 obtain sufficient knowledge of the principles of probabilistic evaluations: analytical calculations (e.g. performed on Boolean or Markovian m
42、odels); 123 and Monte Carlo simulation (e.g. performed on Petri nets 7 ); select an approach suitable with the complexity of the related safety system and the reliability study which is undertaken; handle safety and dependability (e.g. for production assurance purpose, see 3.1.1) within the same rel
43、iability framework. The elementary approaches (e.g. PHA, HAZID, HAZOP, FMECA) are out of the scope of this Technical Report. Yet they are of utmost importance and ought to be applied first as their results provide the input information essential to properly undertake the implementation of the approa
44、ches described in this Technical Report: analytical formulae, Boolean approaches (reliability block diagrams, fault trees, event trees, etc.), Markov graphs and Petri nets. ISO 2013 All rights reserved 1 ISO/TR 12489:2013(E) This Technical Report is focused on probabilistic calculations of random fa
45、ilures and, therefore, the non- random (i.e. systematic failures as per the international reliability vocabulary IEV 191 14 ) failures are out of the scope even if, to some extent, they are partly included into the reliability data collected from the field. 2 Analysis framework 2.1 Users of this Tec
46、hnical Report This Technical Report is intended for the following users, in a role defining the scope of work of reliability models (customer or decision-maker), executing reliability analysis or as a risk analyst using these calculations: Installation/Plant/Facility: operating facility staff, e.g.
47、safety, maintenance and engineering personnel. Owner/Operator/Company: reliability staff or others analysing or responsible for reliability studies for safety related equipment located in company facilities. Industry: groups of companies collaborating to enhance reliability of safety systems and saf
48、ety functions. The use of this Technical Report supports “reliability analytical best practices” for the benefit of societal risk management in accordance with ISO 26000 54 . Manufacturers/Designers: users having to document the reliability of their safety equipment. Authorities/Regulatory bodies: e
49、nforcers of regulatory requirements which can quote these guidelines to enhance quality and resource utilization. Consultant/Contractor: experts and contractors/consultants undertaking reliability modelling and probabilistic calculation studies. University bodies: those having educational roles in society and experts that might improve methods on these matters. Research institutions: experts that might improve reliability modelling and probabilistic calculatio
