TMLs

About Thickness Measurement Locations (TMLs)

A TML is a specific location on an asset where Thickness Measurement readings are taken and for which various values, including minimum thickness, are calculated. Each asset or TML Group can have multiple TMLs associated with it, which stores identifying information. Thickness Measurements are linked to TMLs, which store readings taken at that location.

About Renewing Thickness Measurement Locations (TMLs)

Renewing TMLs provides a mechanism for optionally recording a new base measurement for a TML and setting all existing Thickness Measurements to Inactive. Additionally, the value that was the Controlling Corrosion Rate for the TML prior to the renewal replaces the Minimum Corrosion Rate value in the associated Corrosion Analysis Settings after the renewal. You can renew Thickness Measurement Locations without adding new measurements.

Details

Generally, you will want to renew TMLs when you replace an asset. For example, if an asset representing a tank is linked to one or more TMLs that have Thickness Measurements, when you replace the tank, you can renew the TMLs to retain the measurement data recorded for the old tank while creating a new base measurement for the new tank. When you do this, you can begin calculating Corrosion Analyses for the new tank.

When you renew a TML:

  • In linked Thickness Measurements, if the Measurement Status Indicator field was set to Active prior to the renewal, it will be set to Inactive.
  • The value in the Historical Sequence Number field in linked Thickness Measurements that were used during that life cycle will be incremented. For example, if the Historical Sequence Number field previously contained no value, indicating that the associated TML had never been renewed, it will now be 1, indicating that the associated Thickness Measurement Location record has been renewed one time.
  • The value in the Renew Historical Sequence Number field of the TML will be populated with the largest Historical Sequence Number in the associated Thickness Measurements that were used during that life cycle. For example, assume there are two associated Thickness Measurements that were used during the life cycle. If the Historical Sequence Number of the first measurement is 1 and that of the second measurement is 2, the Renew Historical Sequence Number field in the TML is populated with the value 2. This will keep track of the life cycle for that TML.
  • The value in the Minimum Corrosion Rate field in the Corrosion Analysis Settings for the TML is replaced with the current value in the Controlling Corrosion Rate field in the TML.
  • The value in the Status Changed By field in the TML will update to reflect the User ID of the Security User who renewed the TML.
  • The value in the Status Changed Date field in the TML will change to the current date.

About Moving Thickness Measurement Locations (TMLs)

Under some circumstances, it may be necessary to move TMLs from one asset or TML Group to another. There are two scenarios in which you might perform this task.

Moving TMLs from one Corrosion Analysis to another

You may determine that a TML that was originally linked to one asset or TML Group actually belongs to a different asset or TML Group that is included in a different Corrosion Analysis. In this case, rather than creating a new TML for the correct asset or TML Group, you can relocate the TML.

In this case, you will use Relocate TMLs to select the TML that you want to move and the asset or TML Group to which it will be linked.

Moving TMLs from one TML Group to another in the same Corrosion Analysis

You may determine that a particular subset of existing TMLs actually belong in their own TML Group. If so, you would create a TML Group for the asset, and then move the TMLs to the new TML Group.

In this case, you will use Organize TMLs to move the TMLs from one TML Group to another.

Details

When you move a TML from one asset or TML Group to another:

  • The TML ID of the TML you want to relocate cannot be the same as that of a TML that is already linked to the target asset or TML Group.
  • The TML that you relocate will now be linked only to the target asset or TML Group that you select via the Has Datapoints relationship.
  • The value in the TML Asset ID field of any relocated TML will be updated to reflect the target asset or TML Group.
  • Any Thickness Measurements, TML Corrosion Analyses, and Corrosion Analysis Settings that are linked to a TML will remain linked after the TML is relocated.
  • The Corrosion Analysis Settings for the relocated TML will inherit the values in the Corrosion Analysis Settings that are linked to the target asset or TML Group, with the exception of the following fields:
    • Allowable Measured Variance
    • Corrosion Rate Variance
    • Default Inspection Interval
    • Minimum CR
  • You can select TMLs from multiple source assets or TML Groups for a single relocate operation, but you can select only a single target. If you want to relocate TMLs to more than one target asset or TML Group, you will need to perform the relocate procedure multiple times.
  • After the TMLs are relocated, all calculations will be updated for the Corrosion Analysis that is associated with the source and target asset or TML Groups.

Create a Thickness Measurement Location (TML)

Procedure

  1. Access the Analysis Overview workspace for the asset or TML Group for which you want to create a new TML.
  2. In the left pane, select , and then select TML.

    The Create TML window appears.

  3. In the TML ID box, enter a unique TML ID.
  4. In the Analysis Type box, select the type of analysis that you want to create.

    If you have defined additional required fields for TMLs, proceed to the next step. Otherwise, skip to step 7.

  5. Select Next.

    The TML datasheet appears.

  6. As needed, enter values in the available fields.
  7. Select Done.

    The new TML is created, and the TML Overview workspace appears.

Results

  • The new TML is linked to the record selected in step 1.
  • TML Corrosion Analysis Settings are created automatically for the new TML. The values in the TML Analysis Settings are inherited from the analysis settings for the asset or TML Group selected in step 1.
  • You can modify the TML by accessing the datasheet.

Modify TMLs in Bulk

Procedure

  1. Access the Analysis Overview workspace for the asset or TML Group that you want to modify.
  2. In the workspace, select the TMLs tab.
    The TMLs section appears.

  3. Next to each TML that you want to modify, select the check box, and then, in the upper-right corner of the section, select Edit in Bulk.
    The Bulk Edit TMLs window appears, displaying the selected TMLs.
    Tip: The Bulk Edit TMLs window displays 50 TMLs per page.



  5. As needed, on the Bulk Edit TMLs window, modify the fields.
  6. Select Save, and then select Close.
    The selected TMLs are modified.
    Tip: The TMLs you selected appear in the TML Bulk Edit datasheet.

Define Allowable Stress

About This Task

This topic describes how to define the Allowable Stress value for a TML manually. You can also have GE Digital APM populate the value based on values in a few fields in the TML record. This procedure can be performed before or after you have automatically calculated Allowable Stress for a TML.

Note: Refer to the Allowable Stress reference tables and the method of interpolation used in Thickness Monitoring.

Procedure

  1. Access the TML for which you want to define Allowable Stress.
  2. In the workspace, select the TML Details tab.
    The TML Details section appears, displaying the General Information subsection.

  3. Select the Design General tab.
    The Design General subsection appears.

  4. Select the Override Allowable Stress check box.
    The Allowable Stress box is enabled.
  5. Enter a value in the Allowable Stress box.
  6. In the upper-right corner of the section, select .
    The Allowable Stress value is saved.

Calculate Allowable Stress

About This Task

This topic describes how to have GE Digital APM calculate the value in the Allowable Stress field automatically. You can also define a value manually.

Note: Refer to the Allowable Stress reference tables and the method of interpolation> used in Thickness Monitoring.

Procedure

  1. Access the TML for which you want to define Allowable Stress.
  2. In the workspace, select the TML Details tab.
    The TML Details section appears, displaying the General Information subsection.

  3. Depending on the type of equipment the TML represents (i.e., the component type), enter values in the required fields.
    For Piping and Pressure Vessels, enter values in the following fields:
    • Code Year (Allowable Stress Lookup)
    • Design Code
    • Material Grade
    • Material Specification
    • Design Temperature
    For Tanks of the type Welded Shell, enter values in the following fields:
    • Code Year (Allowable Stress Lookup)
    • Design Code
    • Tank Type
    • Material Grade
    • Material Specification
    • Design Temperature
    For Tanks of the type Annular Ring, enter values in the following fields:
    • Nominal Diameter
    • Maximum Operating Fill Height
    • Plate Thickness
    The Allowable Stress field is populated with a value based on the component type.
  4. In the upper-right corner of the section, select .
    The Allowable Stress value is saved.

Make a Thickness Measurement Location (TML) Inactive

Before You Begin

  • When you make a Thickness Measurement Location (TML) inactive, it will be excluded from any future corrosion analysis calculations.

Procedure

  1. Access the TML that you want to make Inactive.
  2. In the workspace, select the TML Details tab.
    The TML Details section appears, displaying the General Information subsection.

  3. In the Status Indicator box, select Inactive, and then select Save.
    The TML is now inactive.

Delete a Thickness Measurement Location (TML)

Before You Begin

  • When you delete a TML, any linked measurements, Corrosion Analysis Settings, and TM Corrosion Analyses are also deleted.

Procedure

  1. Access the TML that you want to delete.
  2. Select , and then select Delete.

    A message appears, asking you to confirm that you want to delete the TML and any linked Thickness Measurements.

  3. Select Yes.

    The TML is deleted.