1. Typology of critical failure impacts

1.1 Critical failure concepts

The choice of metrics and performance indicators, and the collection of associated data, involve defining the notions of criticality and critical failure. Indeed, since the birth of the first concepts of operational safety in the 1930s, numerous definitions have emerged. In this article, the definition of criticality will be deduced from the American standard on FMEA (Failure Mode, Effect and Criticality Analysis), published on September 10, 1949 as Military Procedure 1629 (MIL-P-1629) and updated by Mil-STD 1629A