Two Risk Matrices are available for the RBI 581 assessment:
Balanced, and
Unbalanced.
Specifying which Risk Matrix to use
To specify which to use:
Click the Edit button
Check Risk Matric Balanced to use the Balanced matrix. If not checked, the Unbalanced matrix will be used for the site’s RBI 581 calculations.
Click Save.
Specifying the Risk Target Criteria
To specify which to use:
Click the Edit button
Select the relevant Risk Target Criteria.
Click Save.
Risk Matrix
The Risk Matrix is shown on the RBI 581 Details Page in the Risk tab and in the right section of the RBI 581 assessment details. The gray circle represents the current Risk value, while the blue line indicates the Criticality Target (in the example below, it’s a PoF target). The blue circle shows the Next Inspection Date (NID), and the Maximum Inspection Interval (MII) is the number of years it will take for the Risk to reach the NID, which is why an upward arrow is displayed.
Below is an examples of the matrix in the Risk tab: showing only the Risk circle and the target line. In this case the Risk Target Criteria was set to Medium (M).
Below is the matrix in the Results (right) Pane. It shows a more detailed view with the NID circle, Risk circle, target line, and arrow. In this case the Risk Target Criteria was set to Medium (M).
Below is an example of the matrix in the right section where a PoF Target of 3 is used as Criticality Target.
Timeline
The "timeline" (a black line with dots) indicates which cells contain dates. Hover on the dot to see the date. Additionally, a moving blue dot represent the current risk (our position on the timeline).
Risk Chart and Table
The API 581 calculation provides a comprehensive series of results that trace the progression of risk from PoF at Age 0 up to PoF at Age 50 years. These results include:
Age: The component's age at a certain point in time.
Date: The date when a certain PoF level is exceeded.
PoF (Probability class): The class of probability.
PoF (Calculated Probability): The calculated probability.
CoF: The Consequence of Failure.
Risk Category: The risk category at a certain point in time.
To provide a clear overview of the risk assessment, the data is visually represented in both a chart and a table view.
The Risk Chart (Plot) visually highlights the remaining time until the next predicted change in the Probability of Failure.
To see the information in table format click the Table tab.
Additional Information shown on the Risk tab
The Risk tab also shows the Risk Matrix Type and the Risk Target Criteria, which are defined in the Criticality and Probability Default Values table found in the RBI 581 Specific Data settings. Alternatively to the Risk Target Criteria, the PoF Target, or Legal/Local Inspection Interval Target can be set to be used as Criticality Target. The Risk Matrix Type and Risk Target Criteria values originate from either site, plant, or unit level and this location name is shown in the Location field. Clicking on the Location name will take you to the settings, where you can modify the default values and access more information (if you have a relevant Role).
Non-Age-Related and Strategy Based Degradation Mechanisms
For a NAR or Strategy-based Degradation Mechanism, Age is not considered - meaning the risk remains constant over time. As a result, the Risk Target Criteria, chart and table tabs, and the blue risk target line (seen with Age-Related DFs) are not shown. The future risk indicator is also omitted, since the risk does not change.
