4.3 RATE OF OCCURRENCE OF
FAILURE (ROCOF)
It is the number of failures occurring in unit time interval.The
number of unexpected events over a particular time of
operation. ROCOF is the frequency of occurrence with which
unexpected behavior is likely to occur. An ROCOF of 0.02
means that two failures are likely to occur in each 100
operational time unit steps. It is also called failure intensity
metric.