A Safety Function is the action of a collection of equipment to implement automatic mitigation of a particular hazard. It is the job of the Safety Instrumented Function (SIF).

Some examples of common Safety Functions: 

  • Car brake stop
  • ESD valve – Shutdown process
  • Sprinkler system 
  • High pressure in a vessel opens a vent valve
  • Guard sensing/speed sensing functions
  • Coolent valve - Open 
  • Overflow sensing functions

An example of a safety function is shown below. Note: The Basic Process Control System (BPCS) is also shown in green, where the safety function is highlighted in orange. 


Related Items

Back to Basics 01 - Functional Safety

Back to Basics 02 - Safety Integrity Level (SIL)

Back to Basics 03 - Safety Instrumented Function (SIF)

Back to Basics 04 - Safety Instrumented System (SIS)

Tagged as:     SIF     safety instrumented function     Loren Stewart     BPCS  

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