Assessment of independent protection layers in an LOPA study-Part 1

摘要

Industrial facilities,especially those operating in the chemical,oil and gas and petroleum industries,contain inherent risks in operations due to the processing of materials that are hazardous in nature.Hazards,operability issues,associated risks and their consequences must be accurately identified and analyzed to ensure safe operations.Safety instrumented systems(SISs)are deployed to reduce risk to tolerable or acceptable levels to achieve safe operations.1 The reliability of safety functions implemented in an SIS is determined by the magnitude of risk reduction required and is expressed in terms of safety integrity level(SIL).A layer of protection analysis(LOPA)is one of the methods used to determine the SIL of the safety instrumented function(SIF).During the LOPA study,the design is thoroughly examined for one or more independent protection layers(iPLs)in the design to assess whether the required risk reduction has been achieved.The success of the LOPA study depends on proper assessment of the protection layers and their contribution to risk reduction.