The Industrial process industry is experiencing a dynamic growth in Functional Process Safety applications. This growth has been driven by increased awareness of destruction of property, injuries and loss of life associated with tragic events that are widely publicized in mass media worldwide. The recent tragedies like the Gulf Oil spill, the fertilizer plant explosion in Texas; nuclear disasters etc. are recent live examples. Companies have a moral and legal obligation to limit risk posed by their operations. In addition to their social responsibilities, the costs of litigation measuring in the billions of dollars have caught the eye of risk management executives worldwide. As a result, management recognizes the financial rewards of utilizing a properly designed process system that optimizes reliability and safety. Hence companies are actively taking steps to comply with various national and worldwide safety standards such as ANSI/ISA 84 and IEC 61508/61511. To accomplish this, safety practitioners look to equipment specifically designed and approved for use in Safety Instrumented Systems that utilize Electrical and/or Electronic and/or Programmable (E/E/PE) technologies. Safety Instrumented Systems (SIS) and functions (SIF) A Safety Instrumented System (SIS) is designed to be used to implement one or more Safety Instrumented Functions (SIF). SIS is composed of any combination of primary sensors (like Pressure & Temperature switches), controllers and final control elements for the purpose of taking a process to a safe state when predetermined conditions are violated. These SIS devices are designed and used to prevent or mitigate hazardous events to protect people or the environment or prevent damage to process equipment.
ITT Corporation (2013) Understanding Safety Integrity Level (SIL) and It’s Effects