LOPA and SIL STUDY

For each process hazard where the LOPA study concludes that existing protection cannot reduce risk to an acceptable or tolerable level, a Safety Instrumented System is required. Not all process hazards will require the use of a SIS. Each hazard that requires the use of an SIS must be assigned a target SIL level. Safety Instrumented Systems (SIS) are installed in Process Plants to mitigate process hazards by taking the process to a “safe state” when predetermined set points have been exceeded or when safe operating conditions have been transgressed. The SIS is one Protection Layer in a multi-layered safety approach since no single safety measure alone can eliminate risk.