In safe hands

This article reviews how the effectiveness (i.e., the ability to perform an intended function) of electrical systems can in be analyzed using the technique of layer of protection analysis (LOPA). It is a process currently in use to determine if instrumented systems are effective in reducing possible risks from the release of hazardous chemicals. This technique can be used to evaluate mandatory protection of electrical systems, nonmandatory protection of electrical systems, alternate system designs, and intervals of maintenance on electrical systems in terms of their potential reliability risks or personnel risks.