Safety Instrumented System Design

This book describes the design phase of the SIS safety life cycle as defined in IEC 61511:2016. Starting with a description of the entire safety life cycle process, the authors show how the design steps fit into that process starting with conceptual design through design verification. The book explains the advantages of the performance-based approach to design and provides the theoretical background for the probabilistic calculations that are the foundation of performance verification. The book also explains minimum redundancy concepts and equipment qualification. By providing numerous examples, the authors explain potentially confusing language from IEC 61511 and IEC 61508. Appendices include statistics, probability, failure-rate data tables, and system architectures. Each chapter contains questions and answers similar to those found on professional certification exams for functional safety, which makes the book a valuable resource for those seeking to achieve personnel certification.

About the Book ix About the Authors xi Chapter 1. The SIS Safety Life Cycle 1 Chapter 2. Safety Instrumented Systems 21 Chapter 3. Failure 31 Chapter 4. Basic Reliability Engineering 45 Chapter 5. System Reliability Engineering 65 Chapter 6. Equipment Failure Modes 95 Chapter 7. Obtaining Failure Rate Data 103 Chapter 8. SIF Design and Verification Process 125 Chapter 9. SIF Probabilistic Verification 155 Chapter 10. SIS Sensors 181 Chapter 11. Logic Solvers 217 Chapter 12. Final Elements 235 Chapter 13. Typical SIF Solutions 275 Chapter 14. Industry Examples 311 Chapter 15. Maintaining the SIS 327 Exercises 346 References 346 Appendix A. Statistics 349 Appendix B. Probability 363 Appendix C. Failure Rate Data 377 Appendix D. System Architectures 383 Appendix E. Answers to Exercises 407 Index 427