What is Severity Occurrence Detection & RPN Number in FMEA?

→ Severity Occurrence Detection and RPN Number is commonly used in FMEA.

→ “Severity” is a ranking number associated with the most serious effect for a given failure mode, based on the criteria from a scale.

→ It assesses the impact of the failure mode (the error in the process)

→ It is a relative ranking within the scope of the specific FMEA and is determined without regard to the likelihood of occurrence or detection.

→ With 1 representing the least safety concern & 1

0 representing the most dangerous safety concern.

→ In most cases, processes with severity scores exceeding 8 may require a fault tree analysis, which estimates the probability of the failure mode by breaking it down into further sub-elements.

→ The severity ranking is based on a relative scale ranging from 1 to 10.

→ A “10” means the effect has a dangerously high severity leading to a hazard without warning.

→ Conversely, a ranking of “1” means the severity is extremely low.



