IEC 61511-3-2016 Functional safety - Safety instrumented systems for the process industry sector - Part 3 Guidance for the determination of the required safety .pdf

1、 IEC 61511-3 Edition 2.0 2016-07 REDLINE VERSION Functional safety Safety instrumented systems for the process industry sector Part 3: Guidance for the determination of the required safety integrity levels IEC 61511-3:2016-07 RLV(en) colour inside THIS PUBLICATION IS COPYRIGHT PROTECTED Copyright 20

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11、or the process industry sector Part 3: Guidance for the determination of the required safety integrity levels INTERNATIONAL ELECTROTECHNICAL COMMISSION ICS 13.110; 25.040.01 ISBN 978-2-8322-3545-4 Registered trademark of the International Electrotechnical Commission Warning! Make sure that you obtai

12、ned this publication from an authorized distributor. colour inside 2 IEC 61511-3:2016 RLV IEC 2016 CONTENTS FOREWORD. 7 INTRODUCTION . 9 1 Scope 12 2 Normative references 13 3 Terms, definitions and abbreviations 14 Annex A (informative) Risk and safety integrity general guidance 15 A.1 General . 15

13、 A.2 Necessary risk reduction . 15 A.3 Role of safety instrumented systems 15 3.4 Safety integrity . A.4 Risk and safety integrity 17 A.5 Allocation of safety requirements . 18 A.6 Hazardous event, hazardous situation and harmful event . 18 A.7 Safety integrity levels 19 A.8 Selection of the method

14、for determining the required safety integrity level 19 Annex B (informative) Semi-quantitative method event tree analysis 22 B.1 General Overview . 22 B.2 Compliance with IEC 61511-1:2016 . 22 B.3 Example . 23 B.3.1 General . 23 B.3.2 Process safety target level . 24 B.3.3 Hazard analysis . 24 B.3.4

15、 Semi-quantitative risk analysis technique 25 B.3.5 Risk analysis of existing process 26 B.3.6 Events that do not meet the process safety target level . 29 B.3.7 Risk reduction using other protection layers 30 B.3.8 Risk reduction using a safety instrumented function 30 Annex C (informative) The saf

16、ety layer matrix method 34 C.1 Introduction Overview 34 C.2 Process safety target 35 C.3 Hazard analysis 36 C.4 Risk analysis technique . 36 C.5 Safety layer matrix 37 C.6 General procedure 38 Annex D (informative) Determination of the required safety integrity levels A semi- qualitative method: cal

17、ibrated risk graph . 40 D.1 Introduction Overview 40 D.2 Risk graph synthesis . 40 D.3 Calibration 41 D.4 Membership and organization of the team undertaking the SIL assessment 42 D.5 Documentation of results of SIL determination . 43 D.6 Example calibration based on typical criteria 43 D.7 Using ri

18、sk graphs where the consequences are environmental damage 46 D.8 Using risk graphs where the consequences are asset loss . 47 D.9 Determining the integrity level of instrument protection function where the consequences of failure involve more than one type of loss 47 IEC 61511-3:2016 RLV IEC 2016 3

19、Annex E (informative) Determination of the required safety integrity levels A qualitative method: risk graph . 48 E.1 General . 48 E.2 Typical implementation of instrumented functions 48 E.3 Risk graph synthesis . 49 E.4 Risk graph implementation: personnel protection . 50 E.5 Relevant issues to be

20、considered during application of risk graphs . 53 Annex F (informative) Layer of protection analysis (LOPA) . 54 F.1 Introduction Overview 54 F.2 Layer of protection analysis F.2 Impact event . 55 F.3 Severity level 55 F.4 Initiating cause 56 F.5 Initiation likelihood 57 F.6 Protection layers . 57 F

21、.7 Additional mitigation 58 F.8 Independent protection layers (IPL) . 58 F.9 Intermediate event likelihood . 59 F.10 SIF integrity level 59 F.11 Mitigated event likelihood 59 F.12 Total risk . 59 F.13 Example . 60 F.13.1 General . 60 F.13.2 Impact event and severity level 60 F.13.3 Initiating cause

22、60 F.13.4 Initiating likelihood . 60 F.13.5 Protection layers General process design . 60 F.13.6 BPCS 60 F.13.7 Alarms . 60 F.13.8 Additional mitigation . 61 F.13.9 Independent protection level layer(s) (IPL) 61 F.13.10 Intermediate event likelihood 61 F.13.11 SIS 61 F.13.12 Next SIF 61 Annex G (inf

23、ormative) Layer of protection analysis using a risk matrix 63 G.1 Overview 63 G.2 Procedure . 65 G.2.1 General . 65 G.2.2 Step 1: General Information and node definition . 65 G.2.3 Step 2: Describe hazardous event . 66 G.2.4 Step 3: Evaluate initiating event frequency . 69 G.2.5 Step 4: Determine ha

24、zardous event consequence severity and risk reduction factor 70 G.2.6 Step 5: Identify independent protection layers and risk reduction factor . 71 G.2.7 Step 6: Identify consequence mitigation systems and risk reduction factor . 72 G.2.8 Step 7: Determine CMS risk gap . 73 G.2.9 Step 8: Determine s

25、cenario risk gap 76 G.2.10 Step 9: Make recommendations when needed . 76 4 IEC 61511-3:2016 RLV IEC 2016 Annex H (informative) A qualitative approach for risk estimation any IEC National Committee interested in the subject dealt with may participate in this preparatory work. International, governmen

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