Layers of protection analysis

Layers of protection analysis (LOPA) is a technique for evaluating the hazards, risks and layers of protection associated with a system, such as a chemical process plant. In terms of complexity and rigour LOPA lies between qualitative techniques such as hazard and operability studies (HAZOP) and quantitative techniques such as fault trees and event trees. LOPA is used to identify scenarios that present the greatest risk and assists in considering how that risk could be reduced.