Functional Safety

Functional safety is part of the overall safety that depends on a system or equipment operating correctly in response to its inputs. Neither safety nor functional safety can be determined without considering the systems as a whole and the environment with which they interact.

The instrumented safety systems are not new. It has long been the practice to fit protective systems to industrial process plant where there is a potential threat to life or to the environment in the event of malfunction. These systems are independent of the normal process control, and take some action to render the plant safe in the event of a malfunction. Safety integrity level (SIL) provides a target to be achieved for such systems.

IEC 61508 is the basic functional safety publication which can be applied across all industries. It is titled “Functional Safety of Electrical/Electronic/Programmable Electronic Safety-related Systems (E/E/PE, or E/E/PES)”.