Severity is a rating corresponding to the seriousness of the effect(s) of a potential equipment failure mode. Severity is comprised of three components: safety considerations to equipment operator or downstream customer, equipment downtime, and defective parts. A reduction in Severity Rating index can be effected only through a design change.
Assess the seriousness of each effect listed in Column 11. Safety of the personnel is the primary criteria in determining the rating.
Note: If a functional approach was used, it may be necessary to list the cause(s) in column 14 before listing the effect(s) first in column 11. This could assist in selecting the appropriate severity rating.
Subsystem functions can be prioritized by rating the severity of the effect that will result from loss of the subsystem function. Estimate the Severity of failure of the subsystem function and enter the rating in the subsystem function worksheet. Rank the functions in descending order. Begin the analysis with the highest ranked functions. Generally, these will be the functions that affect safe equipment operation, government regulations, and customer specification (downtime, defective parts).
The FMEA Team should consent on Severity ratings for each effect listed. The effects on downtime and defective parts are independent events, and the team should select the highest rating that meets the individual criteria (i.e., downtime of 4 hours or defective part loss of 2 to 4 hours of production, select rating of 7; downtime of 40 minutes, or loss of 40 minutes of production, select 5).
Enter the rating for the most serious (highest) effect.