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Evaluating Failures for RCA

Using the RCA view in the Failure or Anomaly window, you can evaluate a failure’s suitability for root cause analysis based on its criticality index. The evaluation produces one of these recommendations:
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RCA not required
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RCA recommended
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RCA required
If RCA is recommended or required, you can create an analysis from the RCA view, or you can create a project to track the creation of the RCA in the future.
APM calculates the criticality index as follows:
Criticality Index = Consequence priority * Failure Severity * Probability of Recurrence
The value of the criticality index, in turn, determines whether RCA is required, recommended, or not required.

Consequence Priority

During the evaluation, the team specifies whether the failure is evident or hidden. Then they determine the failure’s consequence priority by selecting severity values for the health and safety, environmental, and economic consequences. For example:
Note: If the failure references a failure mode, severity values are copied from the failure mode’s risk analysis to the failure’s Consequences tab.
APM calculates the consequence priority by multiplying the severity values by their weighting factors and then applying a rule to the result. For example, the following rule could assign a consequence priority of “Medium”.
Any of(Environmental, Economic, Safety) Is equal to 3.00
Rules can also include the failure record’s downtime and failure costs. The larger the consequence priority number, the greater its priority.

Criticality Index

The criticality index is calculated by multiplying the numbers assigned to the consequence priority, failure severity, and probability of recurrence. For example:

Recommendation

The failure’s evident/hidden value and its criticality index determine the RCA recommendation.
The recommendation is determined by the position of the criticality index value in the recommendation thresholds.
For information about setting up recommendation thresholds and other elements of the evaluation, see Setting up RCA Recommendation Thresholds.

Updating the Failure Analysis Status

When you have completed the evaluation, create the RCA or the analysis request, if appropriate. Then change the failure analysis status to “Completed” or “Not required”. This makes the evaluation read-only and ensures that the status of the failure’s RCA evaluation is accurate when you browse for failures from an RCA.
The value is shown in the Failure analysis status box:
This topic explains how:
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To Evaluate Failures for RCA
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To Update the Failure Analysis Status

To Evaluate Failures for RCA

1.
Open the Failure or Anomaly window and select the RCA view.
2.
Make sure that editing is enabled.
3.
Downtime and downtime costs are compiled from all downtime incidents that reference the failure. Failure costs are copied from the failure record. These costs can be used in the rules that determine the consequence priority. You can change this information, if necessary.
4.
In the Evaluation area, provide the information needed to arrive at a recommendation:
Setting Name
Description
Evident failure
Specify whether the failure is evident or hidden. A hidden failure’s effects do not become apparent to the operating crew under normal circumstances if the failure occurs on its own.
Hidden failures are typically given higher priority for RCA because they often require failure-finding maintenance tasks.
Health and safety
Equipment failure can cause hazards in the workplace. Examples are extreme temperatures, noxious fumes, and the release of liquids that can kill or injure someone.
Select a severity value from the list. Each option has a weighting and severity number that is used to calculate the consequence priority.
Environmental
There is an unacceptable risk that the effects of this failure could breach a known environmental standard or regulation.
Select a severity value from the list. Each option has a weighting and severity number that is used to calculate the consequence priority.
Economic
The economic consequence of failure reflects the financial effect on assets and production. Labor and material costs associated with lost production and with repairing or replacing the damaged equipment are economic consequences.
Select a severity value from the list. Each option has a weighting and severity number that is used to calculate the consequence priority.
Consequence priority
APM calculates the consequence priority by multiplying each severity value by its weighting factor and then applying a rule. For example, a consequence priority of “High” (with a score of 3) might have the rule:
Any of(Environmental, Economic, Safety) Is equal to 4.00
Failure severity
The severity indicates the seriousness of the failure. For example:
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Total: the asset’s performance has decreased to a point where the asset is no longer performing at its required level. The asset has completely failed.
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Partial: the asset’s performance has decreased to a point where it is no longer performing one of its functions at the specified levels. The asset is still functioning.
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Potential: a condition that has been noticed that would result in an actual failure if the problem is not resolved. The actual failure has not yet occurred. Potential failures are normally reported as the result of an indicator reading that has raised a warning alarm against the asset.
To indicate its relative seriousness, each failure severity is assigned a number, which is used to calculate the criticality index.
Probability of recurrence
Probability of recurrence is used to quantify the likelihood of the failure happening again. Each probability is assigned a score, which is used to calculate the criticality index.
Criticality index
The criticality index is calculated by multiplying the numbers assigned to the consequence priority, failure severity, and probability of recurrence. The index is used to determine the recommendation.
Recommendation
The recommendation is based on the criticality index. Possible values are:
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RCA not required
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RCA recommended
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RCA required
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RCA evaluation not performed
The recommendation is determined by the position of the index number in the recommendation thresholds, which are set in RCA settings. The default value is “RCA evaluation not performed”.
5.
If RCA is required or recommended, you can create or request the analysis. See Creating an RCA from a Failure.
6.
Save the failure record. The value in the Failure analysis status box changes to “Performed”.

To Update the Failure Analysis Status

When the evaluation is complete, click the Tools menu, Mark Failure Analysis As, and then click one of:
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Completed
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Not Required
The value in the Failure analysis status box changes accordingly.
The Consequences tab becomes read-only. To alter the evaluation, change the status back to “Not performed”.