Supplementary failure mode and effect analysis (FMEA) for safety application standards DIN EN ISO 13849 safety function-fmea

In the automotive industry, the Safety Function-FMEA according to ISO 26262 and its application to functional safety relevant systems is a well-established process in the form of Automotive Safety Integrity Levels (ASILs). These represent the failure mitigation that must be applied to ensure an acceptable residual risk of malfunctioning behaviour. The DIN EN ISO 13849 (ISO 13849) already describes a process to reduce risks for machines which starts with a Hazard And Risk Analysis (HARA) as described in DIN EN ISO 12100 and concludes with the Safety Requirements Specification (SRS). The SRS is a functional and technical safety concept defining requirements and guidelines to make sure the design conforms to defined safety goals. ISO 13849 lists important faults and failures for various technologies. The defined Safety Functions (SFs) can be classified in corresponding categories that lead to the particular hardware/system structure. This applies to mechatronic systems consisting of at least one sensor, one control unit and one actuator to monitor the system and effect a response in case of failure. Compared to the methods described in ISO 13849, the Safety Function-FMEA allows systematic identification of additional failures resulting from combinations of effects, rather than only listing the main failure causes. Based on the complexity of the machines it is highly recommended to perform a Safety Function-FMEA as a complementary method to assess and improve the overall safety of machinery