Separating process control and safety systems

摘要

Keeping process control and safety systems separate is crucial, but knowing what to separate and integrate and why is critical. Learn about safety instrumented function (SIF) and layers of protection analysis (LOPA). Process safety functions help prevent unplanned substance releases (such as hazardous material) that could result in a major incident. For instance, an operator interacts with a control system -typically a distributed control system (DCS) or programmable logic controller (PLC) - to control a chemical process. If a hazard occurs and the control system can't achieve the required risk reduction on its own, a safety instrumented function (SIF) is implemented to reduce the hazardous risk to an acceptable level. This application of separate layers of protection to reduce the risk of a hazardous event is often called layers of protection analysis (LOPA). If one protection layer fails to mitigate the occurring hazard, an additional layer is added.