Safety Integrity Level Selection: Systematic Methods Including Layer of Protection Analysis This book describes a systematic method for selecting safety integrity levels (SILs) for safety instrumented systems (SISs). The method emphasizes accounting for existing layers of protection, and it ensures that the maximum return on risk reduction investments is achieved. This reference demonstrates the application of quantitative risk analysis techniques and tools to the problem of safety integrity level selection. Essential theory is distilled into a format that the average control systems engineer can quickly apply. This is not a generic theoretical dissertation, nor a comprehensive treatment of the topic of quantitative risk analysis. It is a focused process for applying simple, yet powerful, tools of quantitative risk analysis specifically to the problem of selecting safety integrity levels for safety instrumented systems. Congratulations to Ed Marszal and Eric Scharpf for receiving the Thomas G. Fisher Award of Excellence for a Standards-Based Book Publication for their book Safety Integrity Level Selection: Systematic Methods Including Layer of Protection Analysis!