LAYER OF PROTECTION ANALYSIS OF SODIUM HYPOCHLORITE PLANT IN A CHLOR-ALKALI INDUSTRY: A FUZZY LOPA APPROACH

Abstract

Decision making is considered as one of the major activities in any Risk Control strategies associated with the
industry arena. Several methods are used to quantify the risk and subsequently map it according to respective
importance. It becomes difficult to take critical decisions with vague information presented about the competing
parameters. Layer of Protection Analysis (LOPA) is a powerful analytical tool that can be used for risk assessment. It can
be used for analyzing risk, catastrophic failures and assessing the adequacy of protection layers to mitigate process risk.
It is a hazard analysis technique that includes hazard identification and hazard quantification and allows determining the
risk associated with the various hazardous processes by utilizing their severity and the likelihood of the events being
initiated. LOPA is carried out based on the information developed during qualitative hazard evaluation procedures such
as Hazard and Operability study (HAZOP) and Process Hazard Analysis (PHA). Fuzzy Layer of Protection Analysis
(Fuzzy LOPA) presents a new approach to risk assessment based on fuzzy logic and degrees of memberships. This work
particularly focuses on applying a Fuzzy Layer of Protection Analysis (Fuzzy LOPA) to mitigate the accident scenarios
associated with sodium hypochlorite plant in a chlor-alkali industry by providing various Independent Protection Layers
(IPLs) to reduce the risk levels of the scenarios to acceptable limits. The protection provided helps in reducing the risks
posed by the plant by a large amount in an effective manner. It is evident from this study, that the fuzzy LOPA
methodology provides a better risk estimation compared to classical LOPA and helps in prioritizing the possible
hazardous events of process industries and improves the overall safety of the plant