The Safety Critical Systems Handbook, Fifth Edition presents the latest guidance on safety-related systems that guard workers and the public against injury or death and also address environmental risks. It has been fully revised and contains additional material on risk assessment, cyber security, COMAH and HAZID, published guidance documents/standards, quantified risk assessment and new worked examples. The book provides a comprehensive guide to the revised IEC 61508 standard as well as the 2016 IEC 61511. It enables engineers to determine the required integrity targets and to assess if proposed or existing equipment meet the safety integrity levels required by the various standards and guidance. Functional safety is applicable to all industry sectors and, thus, this book will have a wide readership not only in the chemical and process industries but embraces oil and gas, power generation, avionics, automotive, manufacturing and other sectors. It is aimed at most engineers including project, control & instrumentation, design and maintenance disciplines.