LOPA (Layer of Protection Analysis) is a quantitative risk assessment technique focused on establishing a tolerable frequency for each consequence resulting from an impact event. It simplifies risk assessment by using order of magnitude categories for initiating event frequency, consequence severity, and the likelihood of failure of independent protection layers (IPLs) to approximate risk.
LOPA builds upon information from qualitative hazard evaluations, such as process hazard analyses (PHA), and is implemented using a set of defined rules. The primary aim of LOPA is to identify and quantify the countermeasures or protective layers available to mitigate the potential consequences of identified hazards. These protective layers must be independent to effectively manage the risk.
