FMECA Assessment for Railway Safety-Critical Systems Investigating a New Risk Threshold Method

This paper develops a Failure Mode, Effects and Criticality Analysis (FMECA) for heating, ventilation air conditioning (HVAC) system in railway. HVAC is safety critical which must ensure emergency case of fire loss primary functions. A study the HVAC's areas mandatory to optimize its reliability availability consequently guarantee low operation maintenance cost. The first part describes FMECA performed reported highlight main criticalities under analysis. Secondly, deals with problem evaluation threshold risk value, can distinguish negligible failure modes. Literature barely considers an objective estimation. Therefore, new analytical method based on finite difference introduced find univocal value. then tested two Risk Priority Number datasets related same HVAC. obtained both cases good tradeoff between mitigation cost investment corrective actions required mitigate level. Finally, proposed compared methods available literature. comparison shows that well-structured technique, computational Furthermore, approach provides results line literature, but it completely deletes subjectivity.