Detection failure rate (FR) indicates the number of detectable occurrences of a failure mode over some time period. The units are usually the number of detectable failures per either million hours (FPMH) or billion hours (FITs). Detection FR is calculated for parts and assemblies. You can insert Detection Failure Rate in the FMEA Tree Items table. If this field is blank, a value of 100% is assumed.

The equation for calculating detection FR is a summation across all modes of:

For an assembly, all modes are accounted for in the detection FR, including the modes inserted for the children of that assembly. If you do not want to detect the modes at lower levels but want to use only the modes at the assembly level in the equation, enter a zero for Detection Fault Percentage for modes at lower levels.