Safety Critical Systems Handbook book cover

Safety Critical Systems Handbook


Safety Critical Systems Handbook: A Straightfoward Guide to Functional Safety, IEC 61508 (2010 Edition) and Related Standards, Including Process IEC 61511 and Machinery IEC 62061 AND ISO 13849, Third Edition, offers a practical guide to the functional safety standard IEC 61508. The book is organized into three parts. Part A discusses the concept of functional safety and the need to express targets by means of safety integrity levels. It places functional safety in context, along with risk assessment, likelihood of fatality, and the cost of conformance. It also explains the life-cycle approach, together with the basic outline of IEC 61508 (known as BS EN 61508 in the UK). Part B discusses functional safety standards for the process, oil, and gas industries; the machinery sector; and other industries such as rail, automotive, avionics, and medical electrical equipment. Part C presents case studies in the form of exercises and examples. These studies cover SIL targeting for a pressure let-down system, burner control system assessment, SIL targeting, a hypothetical proposal for a rail-train braking system, and hydroelectric dam and tidal gates.


Chemical, Process, Plant, Oil & Gas and related systems safety engineers

Hardbound, 288 Pages

Published: November 2010

Imprint: Butterworth Heinemann

ISBN: 978-0-08-096781-3


  • A quick overview

    The 2010 version of IEC 61508


    Part A: The Concept of Safety Integrity 1

    Chapter 1 The Meaning and Context of Safety Integrity Targets

    1.1 Risk and the Need for Safety Targets

    1.2 Quantitative and Qualitative Safety Targets

    1.3 The Life-cycle Approach

    1.4 Steps in the Assessment Process

    1.5 Costs

    1.6 The Seven Parts of IEC 61508

    Chapter 2 Meeting IEC 61508 Part 1

    2.1 Establishing Integrity Targets

    2.2 ALARP (“As low as Reasonably Practicable

    2.3 Functional Safety Management and Competence

    IEC 61508 Part 1

    Chapter 3 Meeting IEC 61508 Part 2

    3.1 Organizing and Managing the Life-cycle

    3.2 Requirements Involving the Specification

    3.3 Requirements for Design and Development

    3.4 Integration and Test (Referred to as Verification

    3.5 Operations and Maintenance

    3.6 Validation (Meaning Overall Acceptance Test and the Close Out-of Actions)

    3.7 Safety Manuals

    3.8 Modifications

    3.9 Acquired Sub-systems

    3.10 “Proven in Use” (Referred to as Route 2s in the Standard

    3.11 ASICs and CPU Chips

    3.12 Conformance Demonstration Template

    IEC 61508 Part 2

    Chapter 4 Meeting IEC 61508 Part 3

    4.1 Organizing and Managing the Software Engineering

    4.2 Requirements Involving the Specification

    4.3 Requirements for Design and Development

    4.4 Integration and Test (Referred to as Verification

    4.5 Validation (Meaning Overall Acceptance Test and Close Out of Actions

    4.6 Safety Manuals

    4.7 Modifications

    4.8 Alternative Techniques and Procedures

    4.9 Data Driven Systems

    4.10 Some Technical Comments

    4.11 Conformance Demonstration Template

    IEC 61508 Part 3

    Chapter 5 Reliability Modeling Techniques

    5.1 Failure Rate and Unavailability

    5.2 Creating a Reliability Model

    5.3 Taking Account of Auto-test

    5.4 Human Factors

    Chapter 6 Failure Rate and Mode Data

    6.1 Data Accuracy

    6.2 Sources of Data

    6.3 Data Ranges and Confidence Levels

    6.4 Conclusions

    Now try the exercise and the example, which are Chapters 11 and 12.

    Chapter 7 Demonstrating and Certifying Conformance

    7.1 Demonstrating Conformance

    7.2 The Current Framework for Certification

    7.3 Self Certification (Including Some Independent Assessment

    7.4 Preparing for Assessment

    7.5 Summary

    Part B: Specific Industry Sectors

    Chapter 8 Second-tier Documents e Process, Oil and Gas Industries

    8.1 IEC International Standard 61511: Functional Safety - Safety Instrumented Systems for the Process Industry Sector

    8.2 Institution of Gas Engineers and Managers IGEM/SR/15: Programmable Equipment in Safety-related Applications e 5th Edition 2010

    8.3 Guide to the Application of IEC 61511 to Safety Instrumented Systems in the UK Process Industries

    8.4 ANSI/ISA-84.00.01 (2004) e Functional Safety, Instrumented Systems for the Process Sector

    8.5 Recommended Guidelines for the Application of IEC 61508 and IEC 61511 in the Petroleum Activities on the Norwegian Continental Shelf OLF-070

    Chapter 9 Machinery Sector

    9.1 EN ISO 14121

    9.2 EN ISO 13849

    9.3 BS EN 62061

    Chapter 10 Other Industry Sectors

    10.1 Rail

    10.2 UK MOD Documents

    10.3 Earth Moving Machinery

    10.4 C Coding Standard (MISRA e Motor Industries Research Association) e Development Guidelines for Vehicle Based Programmable Systems

    10.5 Automotive

    10.6 IEC International Standard 61513: Nuclear Power Plants - Instrumentation and Control for Systems Important to Safety - General Requirements for Systems

    10.7 Avionics

    10.8 Medical e IEC 60601 Medical Electrical Equipment, General Requirements for Basic Safety and Essential Performance

    10.9 Stage and Theatrical Equipment

    10.10 Electrical Power Drives

    10.11 Documents which are now Withdrawn

    Part C: Case Studies in the Form of Exercises and Examples

    Chapter 11 Pressure Control System (Exercise)

    11.1 The Unprotected System

    11.2 Protection System

    11.3 Assumptions

    11.4 Reliability Block Diagram

    11.5 Failure Rate Data

    11.6 Quantifying the Model

    11.7 Proposed Design and Maintenance Modifications

    11.8 Modeling Common Cause Failure (Pressure Transmitters)

    11.9 Quantifying the Revised Model

    11.10 ALARP

    11.11 Architectural Constraints

    Chapter 12 Burner Control Assessment (Example)

    Executive Summary & Recommendations

    12.1 Objectives

    12.2 Integrity Requirements

    12.3 Assumptions

    12.4 Results

    12.5 Failure Rate Data

    12.6 References

    Annex I Fault tree details

    Chapter 13 SIL targeting e some practical examples

    13.1 A Problem Involving EUC/SRS Independence

    13.2 A hand-held Alarm Intercom, Involving Human error in the Mitigation

    13.3 Maximum Tolerable Failure Rate Involving Alternative Propagations to Fatality

    13.4 Hot/cold Water Mixer Integrity

    13.5 Scenario Involving High Temperature Gas to a Vessel

    13.6 Example using the LOPA Technique

    Chapter 14 Hypothetical Rail Train Braking System (Example)

    14.1 The Systems

    14.2 The SIL Targets

    14.3 Assumptions

    14.4 Failure Rate Data

    14.5 Reliability Models

    Chapter 15 Rotorcraft Accidents and Risk Assessment

    15.1 Helicopter Incidents

    15.2 Floatation Equipment Risk Assessment

    Chapter 16 Hydro-electric Dam and Tidal Gates

    16.1 Flood-gate Control System

    16.2 Spurious opening of either of two tidal lock gates involving a trapped vessel

    Appendix 1 Functional Safety Management

    Appendix 2 Assessment Schedule (Checklist)

    Appendix 3 Betaplus CCF Model, Scoring Criteria

    Appendix 4 Assessing Safe Failure Fraction and Diagnostic Coverage

    Appendix 5 Answers to Examples

    Appendix 6 References

    Appendix 7 Quality and Safety Plan

    Appendix 8 Some Terms and Jargon of IEC 61508



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