Risks and hazards are associated with almost all types of industries whether it is automotive, electrical/electronics, chemical/process, food processing and packaging, Pharmaceutical etc. But generally, the hazards are more probabilistic and severe when it comes to the process industry. Achieving complete safety through inherently safe process design may be impractical or impossible and there may still be a residual risk. Safety Instrumented Systems (SISs) provide Functional Safety to address the hazardous events that could occur under all reasonably foreseeable circumstances.

Safety Integrity Level (SIL) rating required for a Safety Instrumented System depends on the tolerable risk and the existing risk for a particular application.