Occurrence Factor

The occurrence factor of a failure mode is the number of times a failure might be expected to occur over the life of the asset. Here is an example of how it is applied.

You have a failure probability curve for your flat screen TV that is based on two failure modes:

  1. Minor, recurring component failures that are repairable but eventually lead to replacement.
  2. Major failure leading to immediate replacement.

Half the end-of-life events are the first mode (recurring minor failures) and half are the second mode (one major failure). On average it takes two minor failures to declare the TV at end of life. Here is how we might model these modes:

Failure Mode 1 - Minor

  • Relative probability: 50%
  • Direct cost: $800 (repair)
  • Degree of destruction: 15% (i.e., replaced component rejuvenates the TV. See destructive vs non-destructive failures)
  • Occurrence factor: 2

Failure Mode 1 - Minor

  • Relative probability: 50%
  • Direct cost: $1200 (replacement)
  • Degree of destruction: 100% (i.e., full replacement of TV)
  • Occurrence factor: 1

Note: The occurrence factor is numerically equivalent to to the relative probability. You could eliminate occurrence factor in this examples by setting the Minor and Major relative probabilities to 100% and 50%, respectively.

Continue to economic life.

 

Fatal error: Allowed memory size of 201326592 bytes exhausted (tried to allocate 35 bytes) in C:\Inetpub\vhosts\advantagebis.com\httpdocs\wikis\bis\inc\auth\plain.class.php on line 281