Download or read book Guidelines for Enabling Conditions and Conditional Modifiers in Layer of Protection Analysis written by CCPS (Center for Chemical Process Safety) and published by John Wiley & Sons. This book was released on 2013-11-18 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt: The initial Layer of protection analysis (LOPA) book published in 2001 set the rules and approaches for using LOPA as an intermediate method between purely qualitative hazards evaluation/analysis and more quantitative analysis methods. Basic LOPA provides an order-of-magnitude risk estimate of risk with fairly reproducible results. LOPA results are considered critical in determining safety integrity level for design of safety instrumented systems. This guideline clarifies key concepts and reinforces the limitations and the requirements of LOPA. The main scope of the guideline is to provide examples of CMs and ECs and to provide concrete guidance on the protocols that must be followed to use these concepts. The book presents a brief overview of Layer of Protection Analysis (LOPA) and its variations, and summarizes terminology used for evaluating scenarios in the context of a typical incident sequence. It defines and illustrates the most common types of ECs and CMs and shows how they interrelate to risk criteria as well as their application to other methods.