Corrosion Loops

About Corrosion Loops

A Corrosion Loop is a collection of components grouped together for the purpose of conducting an RBI 581 Risk Analysis.

In APM, Corrosion Loops are used to store relevant identifying and grouping information of the loop. Each Corrosion Loop is linked to other records to further define the Corrosion Loop. For example, Corrosion Loops are linked to Potential Degradation Mechanisms (PDMs), which define the ways in which the components in the Corrosion Loop can fail.

Corrosion Loop

The following image illustrates the records and links that you might create if you want to perform an RBI 581 Risk Analysis on the RBI Components that are involved in an Overhead system.

Access an RBI Corrosion Loop

Procedure

Access the Unit Summary workspace of the process unit that is linked to the Corrosion Loop you want to access.
In the left pane, select the Corrosion Loop that you want to access.
The Corrosion Loop: <name> workspace appears, displaying the following information:
- The Corrosion Loop Details section: Contains the Corrosion Loop datasheet.
- The Potential Degradation Mechanisms section: Contains a list of Potential Degradation Mechanisms (PDMs) that are linked to the Corrosion Loop.
- The Corrosion Loop Overview section: Contains a list of RBI Components related to the corrosion loop.

Create an RBI Corrosion Loop

About This Task

This topic describes how to create a Corrosion Loop and link it to a Process Unit. You can also link an existing Corrosion Loop to a Process Unit.

Procedure

Access the Process Unit for which you want to create a Corrosion Loop.
In the left pane, select , and then select Create New Corrosion Loop.
The Corrosion Loops Details section appears, displaying a blank datasheet for the Corrosion Loop. The value in the RBI Corrosion Loop ID field is populated automatically.
As needed, enter values in the available fields.
In the upper-right corner of the section, select .
The RBI Corrosion Loop is created and linked to the selected Process Unit.

What To Do Next

Link Potential Degradation Mechanisms (PDMs) to an RBI Corrosion Loop

Link RBI Corrosion Loops to a Process Unit

About This Task

This topic describes how to link an existing Corrosion Loop to a Process Unit. You can also create a new Corrosion Loop and link it to a Process Unit.

Procedure

Access the Process Unit to which you want to link Corrosion Loops.
In the left pane, select , and then select Link Existing Corrosion Loop.
The Select Corrosion Loops window appears, displaying a list of Corrosion Loops that are not yet linked to a process unit.
In the row containing each Corrosion Loop that you want to link to the unit, select the check box, and then select Done.
The selected Corrosion Loops are linked to the unit.

What To Do Next

Link Potential Degradation Mechanisms (PDMs) to an RBI Corrosion Loop.

Unlink an RBI Corrosion Loop from a Unit

Procedure

Access the Process Unit from which you want to unlink a Corrosion Loop.
In the left pane, select the Corrosion Loop that you want to unlink, and then select .

A message appears, asking you to confirm if you want to unlink the selected Corrosion Loop.
Select Yes.

The selected RBI Corrosion Loop is unlinked from the unit.

Link Potential Degradation Mechanisms (PDMs) to an RBI Corrosion Loop

About This Task

When you link PDMs to an RBI Corrosion Loop, the PDMs are applied to all the RBI Components contained in that RBI Corrosion Loop.

This topic describes how to link one or more PDMs to a Corrosion Loop. You cannot create PDMs; you can only link them. Therefore, a PDM must already exist to be linked to a Corrosion Loop.

Procedure

Access the Corrosion Loop to which you want to link PDMs.
In the workspace, select the Corrosion Loop Details tab.

The CORROSION LOOP DETAILS and the POTENTIAL DEGRADATION MECHANISMS sub-sections appear.
In the POTENTIAL DEGRADATION MECHANISMS sub-section, select .
A list of PDMs appears, displaying the methodology type of each PDM.
Tip: If you select the link that corresponds to a PDM, the PDM record appears in Record Explorer on a new page.
In the row containing each PDM that you want to link to the Corrosion Loop, select the check box, and then select OK.
The selected PDMs are linked to the Corrosion Loop.

What To Do Next

Unlink a Potential Degradation Mechanism (PDM)

Procedure

Access the Corrosion Loop from which you want to unlink a PDM.
In the workspace, select the Corrosion Loop Details tab.

The CORROSION LOOP DETAILS, and the POTENTIAL DEGRADATION MECHANISMS sub-sections appear. The POTENTIAL DEGRADATION MECHANISMS sub-section displays a list of associated PDMs.
In the POTENTIAL DEGRADATION MECHANISMS sub-section, select the row that contains the PDM that you want to unlink from the RBI Corrosion Loop, and then select .
A message appears, asking you to confirm that you want to unlink the selected PDM.
Select Yes.
The PDM is unlinked from the selected RBI Corrosion Loop.

Suggest and Link PDMs to RBI Components associated with a Corrosion Loop

Before You Begin

Ensure that you have entered all field values that are used as a criteria for suggestions in the RBI Components associated with the Corrosion Loop.

Note: The Enable Suggestion of Potential Degradation Mechanism must be selected in the Global Preferences Workspace.

About This Task

The APM provides an option to automatically suggest Potential Degradation Mechanisms (PDMs) for all the RBI Components associated with a Corrosion Loop. You can decide whether to link the suggested PDMs to the RBI Component. The suggestions are generated using the RBI Degradation Mechanism Screening Policy. Screening criteria for each PDM is referred from API 581 and API 571. Both the documents are recommended practices and provides guidelines on how to screen components for individual degradation mechanism.

Additional guidelines or good engineering practices defined within these documents are not made mandatory for suggestion purposes. Also, customers might be defining screening criteria based on historical data. Customers requiring these additional guidelines to be included for suggesting PDMs can make suitable changes to the policy. For more information, refer Policies Used to Suggest PDMs topic.

The baseline policy suggests the following Thinning and Lining Damage Mechanisms for the components based on the criteria.

581-Atmospheric Tank Bottom Corrosion
581-Cooling Water Corrosion
581-Soil Side Corrosion
581-Internal Component Lining Damage
581-High Temperature Oxidation
581-High Temperature Sulfidic and Naphthenic Acid
581-Sulfuric Acid Corrosion
581-Hydrofluoric Acid Corrosion
581-Hydrochloric Acid Corrosion

Note:

You can add sub-policies for each degradation mechanism type that you want to automatically suggest in the RBI Degradation Mechanism Screening Policy.

This topic describes how to use the suggested PDMs to link to an RBI Component associated with the Asset.

Procedure

Access an RBI Corrosion Loop to which you want to suggest PDMs for associated RBI Components.
In the upper-right corner of the workspace, select , and then select Suggest PDMs for Components.
The list of suggested PDMs appears for each RBI Components, displaying the reasons for the suggestions.
Note:
- By default, all suggested PDMs for each RBI Components will be selected to link to the RBI Component.
- You can deselect the PDMs which you do not want to link to the RBI Component.
- You cannot deselect the PDMs that are already linked to the RBI Component.
- Suggestion basis is set from the return nodes in RBI 581 DM Screening - Thinning and Lining Policy and the numerical values will be in imperial UOM.
- The list is grouped by the Component ID field which is unique for each RBI Component.
Select Link.
The suggested PDMs are linked to the RBI components.
Note: The APM supports the suggested PDMs for a maximum of 25 RBI Components per Corrosion Loop with the baseline configuration.

Delete an RBI Corrosion Loop

Before You Begin

If the Corrosion Loop that you want to delete is linked to a Potential Degradation Mechanisms record (PDM), unlink the PDM before deleting the Corrosion Loop.

Procedure

Access the Corrosion Loop that you want to delete.
In the left pane, select .

A message appears, asking you to confirm that you want to delete the selected Corrosion Loop.
Select Yes.
The Corrosion Loop is deleted.