The severity ranking is an estimation of how serious the effects would be if a given failure did occur. In
some cases it is clear, because of past experience, how serious the problem would be. In other cases, it is
necessary to estimate the severity based on the knowledge of the process. There could be other factors to
consider (contributors to the overall severity of the event being analyzed) [3]. Calculating the severity levels
provides for a classification ranking that encompasses safety, production continuity, scrap loss, etc. user. Each
effect is given a severity number (S) from 1 (no danger) to 10 (critical). A failure mode with severity number of
10 results in severe dissatisfaction of the customer and may even result in the physical injury due to the failure.
Severity ratings in the range of 4-6 result in mild dissatisfaction of the customer whereas those in the range of 1-
3 are not so severe and may even be not detected [2], [3], [10]. Table 1 gives the guidelines based on which
severity ratings were given.