© Handermann 2013 FunctionalSafety.net First of all is the hazard identification. Is the most important step to identifying the required safety functions (SF) for the safety instrumented system (SIS).  The hazard identification techniques are: -Failure mode and effects analysis (FMEA); -Failure mode, effects hazard and criticality analysis (FMEHCrA); -Fault tree analysis (FTA); -Hazard and operability study (HAZOP);  Second is the hazard analysis.  The hazard analysis techniques are: -Event tree analysis (ETA); -Fault tree analysis (FTA);  Third is the risk reduction.  The risk reduction analysis techniques are: -Fault tree analysis (FTA); -Failure mode, effects and criticality analysis (FMECrA); -Hazard and operability study (HAZOP); -Event tree analysis (ETA); -Layer of protection analysisi (LOPA);