ISO/TR TECHNICAL REPORT 12489 First edition 2013-11-01 Petroleum, petrochemical and natural gas industries - Reliability modelling and calculation of safety systems Pétrole, pétrochimie et gaz naturel - Modelisation et calcul fiabilistes des systemes de sécurité Reference number IS0/TR 12489:2013(E) ISO Copyright intematioal Organizatin for Standardizatin @IS02013 r networking permitted without license from IHS Not for Resale IS0/TR 12489:2013(E) COPYRIGHTPROTECTEDDOCUMENT @ISO2013 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 Case postale 56 : CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail [email protected] Web www.iso.org Published in Switzerland @ IS0 2013 - All rights reserved or networking permited without license from IHS Not for Resale IS0/TR 12489:2013(E) Contents Page Foreword ..V Introduction. ...vi 1 Scope. 2 Analysis framework 2.1 Users of this Technical Report .2 2.2 IS0/TR 12489 with regard to risk and reliability analysis processes. .2 2.3 Overview of the reliability modelling and calculation approaches considered in this Technical Report. :4 2.4 Safety systems and safety functions 7 3 Terms and definitions. 3.1 Basic reliability concepts ..8 3.2 Failure classification. .20 3.3 Safety systems typology .24 3.4 Maintenance issues.. 25 3.5 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 failures .36 5.5 Human factors .37 5.6 Documentation of underlying assumptions .40 6 Introduction to modelling and calculations. ..41 6.1 Generalities about safety systems operating in "on demand" or “continuous" modes. 6.2 Analytical approaches. 44 7 Analytical formulae approach (low demand mode) ..47 7.1 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 formulae approach .57 8 Boolean and sequential approaches .58 8.1 Introduction 58 8.2 Reliability block diagrams (RBD) ..58 8.3 FaultTreeAnalysis (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 Boolean 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 ii se with ISt ted without license from IHS Not for Resale IS0/TR 12489:2013(E) 10.3Conclusion 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 .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 TA5: emergency depressurization system (EDP) 124 14.7 Conclusion about typical applications 135 Annex A (informative) Systems with safety functions. 136 Annex B (informative) State analysis and fa