Failure Probability

The APM system can perform calculations on the data used in a Reliability Distribution Analysis to estimate how likely it is that a piece of equipment will fail today. Then, using future values that you supply, the APM system can calculate how likely it is that a piece of equipment will fail at some point in the future.

• The current failure probability is based on the current age of the piece of equipment, which is the amount of time that has passed between the last replacement date (i.e., the last failure date) and the End Date of the Analysis Period.
• Two options are available for calculating future failure probability calculations:
  • You can specify an operating time to define a future age for the piece of equipment, and then the APM system will determine how likely it is that a piece of equipment will fail when it has reached that age.
  • You can specify a failure probability, and the APM system will determine the age at which the piece of equipment will reach that likelihood of failing.

The grid in the Failure Probability workspace contains the following columns of information:

• Asset ID: Contains the Asset ID for each piece of equipment included in the analysis.
• Installation Date: Contains the initial date that the piece of equipment was installed.
• Last Replacement: Contains the date the piece of equipment last failed and, as a result, was replaced.
• Present Age: Contains the current age of the piece of equipment. The value in the Present Age column represents the amount of time between the date in the Last Replacement column and the end date of the Analysis Period, expressed in the Time Units selected for the analysis.
• Future Age: The age that is used for determining the value in the Future Failure Probability column. The value in the Future Age column is determined by adding the Operating Time you specified to the Present Age of the piece of equipment.
• Present Failure Probability: The current probability of failure for each piece of equipment based on the present age of the piece of equipment.
• Future Failure Probability: The probability that the piece of equipment will fail between the present time and the value in the Future Age column. The Future Failure Probability is based on the assumption that at the Present Age the piece of equipment has not failed.