What is functional safety?
Functional safety is part of the overall safety that depends on a control system or equipment operating correctly in response to its inputs. Functional safety is achieved when every specified safety function is carried out and the level of performance required of each safety function is met.
Functional safety relies on active systems. The system is continuously monitoring the equipment and takes an executive action to prevent a hazardous event from occurring. An example of such is the temperature monitoring of a chemical reactor which takes appropriate action to stop the feed upon the detection of a runaway reaction, or addition of cooling whichever is defined as the appropriate action.
Passive systems such as fire protection doors, bunds / dykes and protective insulation are not part of the scope of functional safety.
In order to establish if there are any functional safety requirements on your process or system then a hazard analysis should be conducted. This will identify whether functional safety systems are required to ensure that adequate protection is provided for each hazardous event which is present. The outcome of the work will establish the requirements for the functional safety systems.