Practical SIL Target Selection - Risk Analysis per the IEC 61511 Safety Lifecycle

This book has evolved over a number of years from a series of courses, seminars and safety engineering projects exida has completed throughout the world. Unfortunately, the project review and audit experience has shown that it is still very easy to select bad SIL targets. Incorrect or missing input information, insufficient resources, lack of facilitator or team skills, and poor communication between disciplines can each lead to severe under-design and over-design problems. These problems can cost large amounts of money and sometimes even lives, yet they can usually be prevented by rational and careful application of the relatively basic techniques presented in this book. The concepts and techniques described are based on the application of the Safety Lifecycle as it is described in the international standard IEC 61511-2003 with references to IEC 61508. It can also readily be used in machine safety applications. This book expands upon the framework developed in these standards to provide a working guide to apply these concepts and techniques to both retrofit and green field projects in the process and machine automation industries. The techniques cover a range from coarse qualitative screening up to fully detailed numerical modeling and can readily be varied or adapted to suite a wide range of applications.