(14b) Square Pegs in Round Holes: Avoiding Inappropriate Methods When Considering PHA and LOPA Scenarios

Process Hazards Analysis (PHA) and Layers of Protection Analysis (LOPA), when applied appropriately, can be powerful tools to identify potential hazards of a process and develop proper safeguarding strategies to prevent them. However, some scenarios do not fit neatly into the standard PHA and LOPA methodologies, and inappropriate application of these methods to such scenarios may result in incorrect conclusions, either requiring unnecessary additional safety systems, or in the worst case leaving potential significant hazards unidentified and without sufficient preventive safeguards. This paper will identify some common pitfalls of inappropriate application of PHA and LOPA methods, and will suggest appropriate alternative methods, sometimes involving different uses of PHA or LOPA methodology and other times using different study methods all together.