PRD Components

About Pressure Relief Devices (PRD)

A pressure relief device (PRD) is a device that protects equipment or RBI Components from pressure buildup. In RBI, you will store information about PRDs in records belonging to subfamilies of the PRD Components family.

Specifically, RBI supports the use of the following types of PRDs:

Pressure relief valves (stored in Criticality Calculator PRD Component - Relief Valve records)
Rupture disks (stored in Criticality Calculator PRD Component - Rupture Disk records)

Note: Throughout this documentation, where the distinction between the two subfamilies is irrelevant to the discussion, you will see the term PRD Components to refer to a record in either subfamily.

About Identifying Protected Equipment or RBI Components

After you have created a PRD Component to identify a pressure relief device (PRD), you can identify the equipment or RBI Components that the PRD protects.

A PRD can protect either equipment or RBI Components, but not both.
- If a PRD protects equipment, it can protect one or many pieces of equipment.
- If a PRD protects RBI Components, it can protect one or many RBI Components.
A single piece of equipment can be protected by multiple PRDs.
A single RBI Component can be protected by multiple PRDs.
If you identify a new protected equipment or RBI Component for a PRD for which an RBI PRD Analysis already exists, the existing RBI PRD Analysis will become invalid. You will need to create a new RBI PRD Analysis to account for the new protected equipment or RBI Component.

About Integration with Thickness Monitoring (TM)

If the Thickness Monitoring license is active, and TM Analyses exist for the Equipment records that you analyze using RBI, you can specify that TM Analysis values be used to calculate corrosion rate values that are used in RBI at:

The equipment level

-or-
The TML Group level

TM Integration

Suppose that the asset that you are analyzing in TM and RBI represents a shell and tube heat exchanger. The shell and tube heat exchanger has two subcomponents, the shell side and the tube side, each with its own process flow. Since the corrosion environments of these subcomponents differ, you have created the following TML Groups (in the TM module):

TML Group - Shell Side
TML Group - Tube Side

When you first begin analysis on the shell and tube heat exchanger, you are not sure what the TM corrosion data will show, (i.e., whether TML Group - Shell Side or TML Group - Tube Side will have more aggressive corrosion). As a result, you may want to specify in RBI that TM Analysis values at the asset level be used to calculate RBI corrosion rate values.

As you analyze the shell and tube heat exchanger in TM, you notice that a subset of the TMLs on the shell side near the nozzle have very high corrosion rates. At this point, you create a third TML Group, TML Group - Shell Nozzle to represent this subcomponent, and you move the Thickness Measurement Locations associated with this subcomponent from TML Group - Shell Side to TML Group - Shell Nozzle. As a result, you may want to now specify in RBI that TM Analysis values at the TML Group level be used to calculate RBI corrosion rates. Specifically, you want to specify that the TML Corrosion Analysis value associated with TML Group - Shell Nozzle be used to calculate RBI corrosion rates.

RBI and TM Integration Workflow

When you create an RBI Component, specify whether corrosion rate should be considered at the asset level or at the component level. To do so, in the Source of Calculated Corrosion Rate field in the RBI Component, select Asset or Component.
If the value in the Source of Calculated Corrosion Rate field is Asset, then:

The following fields in the associated RBI 581 Thinning and Lining Evaluation are populated with corresponding values in the associated Asset Corrosion Analysis.
- Short Term Avg Corr Rate
- Long Term Avg Corr Rate
- Controlling Corrosion Rate
The following fields in the associated Criticality Int. Corr. Deg. Mech. Eval. are populated with values from the linked TML Group:
- Controlling Corrosion Rate
- Long Term Corrosion Rate
- Short Term Corrosion Rate
If the value in the Source of Calculated Corrosion Rate field is Component, then link the RBI Component to one or more TML Groups.

The aforementioned fields are populated based on the most conservative value (i.e., the highest value) among the corresponding values in the Asset Corrosion Analyses linked to the TML Groups.

The value in the Controlling Corrosion Rate field in the Asset Corrosion Analysis is in mils per year. This value is converted to inches per year, and then used to populate this field.

For example, suppose the Component is linked to two TML Groups whose controlling corrosion rate values are 0.3 mils per year and 0.45 mils per year respectively. These values are stored in the Controlling Corrosion Rate field in the Asset Corrosion Analysis record that is linked to each TML Group.

Since the most conservative value between the two TML Groups is 0.45 mils per year, it is converted to inches per year as 0.00045 inches per year. This value is used to populate the Controlling Corrosion Rate field in the associated RBI 581 Thinning and Lining Evaluation or Criticality Int. Corr. Deg. Mech. Eval.

About Using TM Analysis Values at the Asset Level

Important: If you want to use the TM Analysis values to calculate the corrosion rate values in RBI, make sure to calculate the associated TM Analysis before creating the RBI Analysis.

When you specify that TM Analysis values at the asset level be used to calculate RBI corrosion rate values, the RBI corrosion rate values are determined based on the selected Corrosion Rate for all the TML Corrosion Analyses that are linked. By default, the Source of Calculated Corrosion Rate field in the RBI Component will be set to asset.

When an RBI Component is created and integrated with TM, the Selected Corrosion Rate field of the Criticality Int. Corr. Deg. Mech. Eval. record for the selected asset can contain one of the following values:

Controlling Corrosion Rate
Estimated Corrosion Rate
Long Term Corrosion Rate
Short Term Corrosion Rate

Note: TMLs for which the Controlling Corrosion Rate, Long Term Corrosion Rate, or Short Term Corrosion Rate have not been calculated will be calculated during analysis creation.

Controlling Corrosion Rate Details

When the Source of Controlling Corrosion Rate field is set to Component, and you have multiple TML Groups mapped to the same Component, then the Controlling Corrosion Rate for a TML is determined by evaluating the corrosion rates that have been calculated for the TML. The TML Controlling Corrosion Rate is set to the highest (i.e., most conservative) of these corrosion rates.

Estimated Corrosion Rate Details

The Estimated Corrosion Rate for a TML is the rate of corrosion assigned to the Internal Corrosion Rate of an RBI Component by a subject matter expert.

Long Term Corrosion Rate Details

Long Term Corrosion Rate is a calculation that indicates the rate of corrosion over the full length of time for which measurements have been recorded. The Long Term Corrosion Rate value is calculated for a given TML if the analysis settings for the related Equipment or TML Group specify that Long Term Corrosion Rate should be used.

Short Term Corrosion Rate Details

Short Term Corrosion Rate is the rate of corrosion as determined by the most recently recorded values. The Short Term Corrosion Rate value is calculated for a given TML record only if the analysis settings for the related Asset specify that Short Term Corrosion Rate should be used and there are two or more Thickness Measurements for the TML.

Calculating Short Term and Long Term Average Corrosion Rates

Suppose an Equipment is linked to five TMLs for which five TML Corrosion Analyses exist with the following Long Term Corrosion Rate and Short Term Corrosion Rate values.

TML Corrosion Analysis record	Long Term Corrosion Rate	Short Term Corrosion Rate
1	1.001 MILS/year	1.003 MILS/year
2	1.003 MILS/year	1.003 MILS/year
3	1.001 MILS/year	1.001 MILS/year
4	1 MILS/year	1.001 MILS/year
5	1.001 MILS/year	None

When you create an RBI Criticality Analysis for the RBI Component that corresponds to this piece of equipment, if you specified that TM Analysis values at the equipment level be used to determine RBI corrosion rate values:

The value in the Long Term Avg. Corr. Rate field in the Criticality Int. Corr. Deg. Mech. Eval. is calculated as follows:

Long Term Avg. Corr. Rate = (1.001 + 1.003 + 1.001 + 1 + 1.001) / 5

Long Term Avg. Corr. Rate = 1.0012
The value in the Short Term Avg. Corr. Rate field in the Criticality Int. Corr. Deg. Mech. Eval. is calculated as follows:

Short Term Avg. Corr. Rate = (1.003 + 1.003 + 1.001 + 1.001) / 4

Short Term Avg. Corr. Rate = 1.002

About Using TM Analysis Values at the Thickness Monitoring Location (TML) Group Level

Note: The following information assumes that you are using the RBI module to complete this workflow. Alternatively, you can also use the Thickness Monitoring module to identify the TML Group records whose TML Corrosion Analysis values you want to use to calculate RBI corrosion rates.

When you specify that TM Analysis values at the TML Group level be used to calculate RBI corrosion rate values, the RBI corrosion rate values are determined based on the average of the Long Term Corrosion Rate and Short Term Corrosion Rate values in the TML Corrosion Analyses that are linked to one or more TML Groups that are linked to the Equipment that is being analyzed in TM and RBI. The TML Groups whose TML Corrosion Analysis values are used are determined by your selections on the Link to TML Groups dialog box.

Note: The following information assumes that you are using the RBI module to complete this workflow. Alternatively, you could use the Thickness Monitoring module to identify the TML Group records whose TML Corrosion Analysis values you want to use to calculate RBI corrosion rates.

When you specify that TM Analysis values at the TML Group level be used to calculate RBI corrosion rate values, RBI gets the Controlling Corrosion rate, the Short Term Corrosion Rate (STCR) and Long Term Corrosion Rate (LTCR) values from TM. The values for Long Term Average Corrosion Rate and Short Term Average Corrosion Rate are based on the average of the LTCR and STCR value in TML Corrosion Analysis. The TML Groups whose TML Corrosion Analysis values are used are determined by your selections on the Manage TML Groups window.

While you can specify that RBI Corrosion Rate values be determined by one or more TML Groups by linking the RBI Components to one or more TML Groups, a TML Group can be linked to only one RBI Component.

Note: TMLs for which the Long Term Corrosion Rate or Short Term Corrosion Rate have not been calculated will be excluded from the calculations that determine RBI corrosion rate values.

Calculating Short Term and Long Term Average Corrosion Rates

Suppose an Equipment is linked to three TML Groups whose Thickness Measurement Locations are each linked to five TML Corrosion Analyses with the following Long Term Corrosion Rate and Short Term Corrosion Rate values:

TML Group 1

TML Corrosion Analysis record	Long Term Corrosion Rate	Short Term Corrosion Rate
1	1.005 MILS/year	1.006 MILS/year
2	1.003 MILS/year	1.003 MILS/year
3	1.005 MILS/year	1.006 MILS/year
4	1 MILS/year	1.001 MILS/year
5	1.005 MILS/year	None

TML Group 2

TML Corrosion Analysis record	Long Term Corrosion Rate	Short Term Corrosion Rate
1	1.004 MILS/year	1.004 MILS/year
2	1.008 MILS/year	1.008 MILS/year
3	1.005 MILS/year	None
4	1 MILS/year	1.001 MILS/year
5	1.005 MILS/year	1.006 MILS/year

TML Group 3

TML Corrosion Analysis record	Long Term Corrosion Rate	Short Term Corrosion Rate
1	1.002 MILS/year	None
2	1.003 MILS/year	1.005 MILS/year
3	1.005 MILS/year	1.006 MILS/year
4	1 MILS/year	1.001 MILS/year
5	1.002 MILS/year	1.004 MILS/year

When you create an RBI Analysis for the RBI Component that corresponds to this piece of equipment, if you specified that TM Analysis values at the TML Group 1 level be used to determine RBI corrosion rate values:

The value in the Long Term Avg. Corr. Rate field in the Criticality Int. Corr. Deg. Mech. Eval that is created automatically would be calculated as follows:

Long Term Avg. Corr. Rate = (1.005 + 1.003 + 1.005 + 1 + 1.005) / 5

Long Term Avg. Corr. Rate = 1.0036
The value in the Short Term Avg. Corr. Rate field in the Criticality Int. Corr. Deg. Mech. Eval that is created automatically would be calculated as follows:

Short Term Avg. Corr. Rate = (1.006 + 1.003 + 1.006 + 1.001) / 4

Short Term Avg. Corr. Rate = 1.004

You can specify that TML Corrosion Analysis values from more than one TML Group be used to calculate RBI corrosion rates. If you specified that the TML Corrosion Analysis values associated with TML Group 1 and TML Group 3 be used to determine RBI corrosion rate values:

The value in the Long Term Avg. Corr. Rate field in the Criticality Int. Corr. Deg. Mech. Eval that is created automatically would be calculated as follows:

Long Term Avg. Corr. Rate = (1.005 + 1.003 + 1.005 + 1 + 1.005 + 1.002 + 1.003 + 1.005 + 1 + 1.002) / 10

Long Term Avg. Corr. Rate = 1.003
The value in the Short Term Avg. Corr. Rate field in the Criticality Int. Corr. Deg. Mech. Eval that is created automatically would be calculated as follows:

Short Term Avg. Corr. Rate = (1.006 + 1.003 + 1.006 + 1.001 + 1.005 + 1.006 + 1.001 + 1.004) / 8

Short Term Avg. Corr. Rate = 1.004

Access a PRD Component

About This Task

Important: To distinguish PRD Components from RBI Components in a Corrosion Loop, PRD Components have the icon

before the Component ID. All PRD Components function the same way as RBI Components.

Procedure

Access the Asset Summary workspace for the asset that contains the PRD Component that you want to access.

-or-

Access the Corrosion Loop that contains the PRD Component that you want to access.
Below the graph, select the link corresponding to the component that you want to access.

-or-

In the left pane, select the component that you want to access.

The workspace for the selected component appears, displaying the Component Overview section.
Select the Component Details tab.

The Component Details section appears, displaying the datasheet of the Component.

Note: If needed, modify values in the available fields, and then select to save your changes.

Create a PRD Component

About This Task

This topic describes how to create a new PRD Component and link it to an Asset or a Corrosion Loop. You can also link an existing PRD Component to an Asset or a Corrosion Loop.

Important: To distinguish PRD Components from RBI Components in a Corrosion Loop, PRD Components have the icon

before the Component ID. All PRD Components function the same way as RBI Components.

Procedure

Access the Asset Summary workspace of the asset in which you want to create a PRD Component.

-or-

Access the Corrosion Loop in which you want to create a PRD Component.
In the left pane, select , and then select Create New Component.

The Create New RBI Component window appears.
Enter values in the following fields:
- Asset: This field is automatically populated with the asset for which you are creating a PRD Component.
- Component Family: Select the component family for the Component that you want to create.
- Component Type: Select the component type for the PRD Component that you want to create.
Select Create.

A new PRD Component is created, and is automatically linked to the selected Asset and the Corrosion Loop. The Component Details section appears, displaying the component datasheet.
Enter values in the available fields.
In the upper-right corner of the datasheet, select .

The changes made to the PRD Component are saved.

Results

The PRD Component inherits linked Potential Degradation Mechanisms from the RBI Corrosion Loop.

What To Do Next

Link a Protected RBI Component to a PRD Component.

Link PRD Components to an RBI Corrosion Loop

About This Task

This topic describes how to link existing PRD Components to an Asset or Corrosion Loop. You can also create a new PRD Component.

Important: To distinguish PRD Components from RBI Components in a Corrosion Loop, PRD Components have the icon

before the Component ID. All PRD Components function the same way as RBI Components.

Procedure

Access the Corrosion Loop that you want to link to a PRD Component.
In the left pane, select , and then select Link Existing Component.

The Select RBI Components window appears, displaying a list of components in the same site that are not linked to a Corrosion Loop.
Select the check boxes that correspond to the components that you want to link, and then select Done.

The selected PRD Components are linked to the Corrosion Loop.

Results

The PDMs that are linked to the Corrosion Loop are linked to the PRD Components, in addition to the ones that are directly linked to the component.

What To Do Next

Link a Protected RBI Component to a PRD Component.

Unlink a PRD Component from an RBI Corrosion Loop

About This Task

Important: To distinguish PRD Components from RBI Components in a Corrosion Loop, PRD Components have the icon

before the Component ID. All PRD Components function the same way as RBI Components.

Procedure

Access the Corrosion Loop from which you want to unlink the PRD Component.
In the left pane, select the PRD Component that you want to unlink from the Corrosion Loop, and then select .

-or-

Below the graph, next to the PRD Component that you want to unlink from the Corrosion Loop, select the check box, and then select .

A message appears, asking you to confirm that you want to unlink the selected PRD Component.
Select Yes.

The PRD Component is unlinked from the selected Corrosion Loop.

Link a Protected RBI Component to a PRD Component

Procedure

Access the PRD Component to which you want to link a Protected RBI Component.

Tip: This documentation assumes that you will you will link a Protected RBI Component to a PRD Component. The same operations apply if you link a Protected Asset to a PRD Asset.
In the upper-right corner of the page, select , and then select Add Protected Components.

The Select Protected Components window appears.
In the Hierarchy section, navigate to and select the asset that contains the RBI Component that you want to link.

A list of available RBI Components in the selected asset appear in the Available RBI Components section.
In the Available RBI Components section, select the RBI Component that you want to link.

The selected component appears in the Selected RBI Components section.
Select Done.

The selected RBI Component is now linked to the PRD Component.

What To Do Next

Link Potential Degradation Mechanisms (PDMs) to a PRD Component.

Unlink a Protected RBI Component from a PRD Component

Procedure

Access the PRD Component to which you want to link or unlink a Protected RBI Component.
Tip: This documentation assumes that you will you will unlink a Protected RBI Component from the PRD Component. The same operations apply if you unlink a Protected Asset from a PRD Asset.
In the left pane, select the protected RBI Component that you want to unlink from the PRD Component.
In the left pane, select .

A message appears, asking you to confirm that you want to unlink the selected Protected RBI Component.
Select Yes.

A message appears, specifying that after you link or unlink protected assets or components, you must calculate the RBI PRD Analysis again to view updated results.
Select Yes.

The Protected RBI Component is unlinked from the PRD Component.

Link Potential Degradation Mechanisms (PDMs) to a PRD Component

About This Task

If the PRD Component is linked to a Corrosion Loop, then all the PDMs linked to the Corrosion Loop are also linked to the Component. You can, however, link additional PDMs to the Component.

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

Important: To distinguish PRD Components from RBI Components in a Corrosion Loop, PRD Components have the icon

before the Component ID. All PRD Components function the same way as RBI Components.

Procedure

Access the PRD Component to which you want to link PDMs.
Select the Potential Degradation Mechanisms tab.

The Potential Degradation Mechanisms section appears, displaying a list of PDMs linked to the PRD Component.
Select Add PDM.

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.
Next to each PDM that you want to link to the PRD Component, select the check box, and then select OK.

Note: PDMs that can be used with an RBI 581 Risk Analysis contain a 581 prefix (e.g., 581-Amine Cracking).

The selected PDMs are linked to the PRD Component.

What To Do Next

Create an RBI PRD Criticality Analysis.

Unlink a Potential Degradation Mechanism (PDM) from a PRD Component

About This Task

Important: To distinguish PRD Components from RBI Components in a Corrosion Loop, PRD Components have the icon

before the Component ID. All PRD Components function the same way as RBI Components.

Procedure

Access the PRD Component from which you want to unlink a PDM.
Select the Potential Degradation Mechanisms tab.

The Potential Degradation Mechanisms section appears, displaying a list of PDMs linked to the PRD Component.
In the row that contains the PDM you want to unlink from the PRD Component, select .

A message appears, asking you to confirm that you want to unlink the selected PDM.
Select Yes.

The PDM is unlinked from the PRD Component.

Apply a PRD Component

About This Task

When you apply a PRD Component, you make a copy of the original record. The applied PRD Component is not automatically linked to the original RBI Component's Corrosion Loop. Instead, the applied RBI Component can be linked to the same or a different asset and then to a Corrosion Loop.

Important: To distinguish PRD Components from RBI Components in a Corrosion Loop, PRD Components have the icon

before the Component ID. All PRD Components function the same way as RBI Components.

Procedure

Access the PRD Component that you want to apply.
In the upper-right corner of the page, select .

The Hierarchy Finder window appears.
Navigate through the Hierarchy Finder to select the asset to which you want to apply the PRD Component.
Select OK.

The PRD Component is applied to the selected asset.

What To Do Next

Link PRD Components to an RBI Corrosion Loop

Delete a PRD Component

Before You Begin

About This Task

Important: To distinguish PRD Components from RBI Components in a Corrosion Loop, PRD Components have the icon

before the Component ID. All PRD Components function the same way as RBI Components.

Procedure

Access the Asset Summary workspace of the asset that is linked to the PRD Component that you want to delete.

-or-

Access the Corrosion Loop that is linked to the PRD Component that you want to delete.
Next to the Component what you want to delete, select the check box next, and then select .

A message appears, asking you to confirm that you want to delete the selected PRD Component.
Select Yes.

The PRD Component is deleted, and all links to existing related entities are removed.