What Is A Safety-Related System In The Context Of IEC 61508?

A safety-related system comprises everything (hardware, software and human elements) necessary to carry out one or more safety functions, where failure of the safety function would give rise to a significant increase in the risk to the safety of persons and/or the environment.

A safety-related system can comprise stand-alone equipment dedicated to perform a particular safety function (such as a fire detection system) or can be integrated into other plant or equipment (such as motor speed control in a machine tool).

3.4.1 of IEC 61508-4 gives a formal definition.

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