Automation technology systems are increasingly taking over safety-relevant tasks in processes which represent a risk for people and the environment. In the event of an incident, they intervene in the process and can reduce the risk of a hazardous situation occurring. The functional safety of a plant is safeguarded if every safety function is executed in accordance with specifications. Here, the SIL (Safety Integrity Level) unit of measurementquantifies the risk reduction of a safety-relatedsystem in four separate levels.

Since August 2002, the IEC/EN 61508 standard has comprehensively defined the safety requirements in automation technology and primarily addresses the manufacturers of components for protective equipment. The IEC 61511 standard "Functional safety – Safety instrumented systems for the process industry sector" addresses the operators and designers of protective equipment. It provides recommendations and specifications on assessing the damage risk of plants and helps in selecting suitable, safety-related components.

SIL is the abbreviation for "Safety Integrity Level" and is defined as a measurement of the safety-related performance or reliability of an electronic or electrical control device.