Preparing for an EVA

Preparation for doing an EVA.

Some preparation is needed before you can start an EVA (Extreme Value Analysis). When the hierarchy (Equipment, Circuit, CMLs and MSs) is set up, the inspection data must be inputted into the MSs, and then the EVA can start. The needed preparation is explained below.

Create an Equipment for your HX

When creating a HX Equipment:

• For the Equipment group, select "BUNDLE" or "EXCHANGER".
• Remember to enter the Start Date. This is needed to calculate the CR (Corrosion Rate) later on.
  Create Equipment of group Bundle and specify start date.
  
  

Create a Circuit and Enable EVA

A new Circuit can be added to the Equipment manually or via data import.

To manually add a Circuit:

• On your HX Equipment details page, scroll down to Hierarchy.
• Click on New Circuit.
• Enter the Circuit data in the popup window. Yellow fields are mandatory. (See also Creating new PEI Circuits.)
• Select the Inspection Reason. Note: For most Inspection Reasons the NID will be penalized (by the PERF factor) if not enough CMLs have measurements, only "Class 4" does not.
• Tick the Enable EVA checkbox.
• Enter the Number of tubes.
• Click Save.
• After Save you are redirected to the details page of the Circuit. 
• A CML grid will appears at the bottom of the Circuit page, with EVA rows and columns, and a HX Overview Window will show on the right.
  Create a Circuit and enable EVA.

Note: EVA can also be enabled afterwards on the Circuit details page.

Create the CMLs

Create CMLs to store the thickness measurements. For EVA there are two approaches:

1. Min Tubes: In this approach CMLs are only created for the tubes that will be inspected.
2. All Tubes: In this approach CMLs are created for all the HX tubes, irrespective of whether they will be inspected.

CMLs can be created manually by clicking the + in the CML List Toolbar (see PEI Circuits - Details Page) or in bulk:

• Go to Settings\Data Transfer\Import Data and download the CML Template (see Importing Data via Settings).
• Open the Excel file and enter the CML data.
• Remember to enter the Renewal Thickness and Nominal WT / Nominal Thickness (at Service date) for all CMLs that will be measured. CML Type is "TUBE". HX Row and Column can also be entered. These are coordinates on the HX Overview.

• Save the file.
• Go to Settings\Data Transfer\Import Data.
• Click Browse and select your saved file.
• Select the import type: "CML".
• Click Next and follow the Steps to Import the CMLs.
  CML template.

CML list in IMS.

 

• Go back to your Circuit and view the CMLs.

Map the CMLs to the HX Overview

If desired, the CMLs can be mapped to the HX Overview. Note: This will help with stratification.

• On the Circuit Details Page, scroll down to the CML List and HX Overview.
• Click the auto populate button on the HX Overview Toolbar to populate the HX Overview automatically. The button is only active when the HX Overview is empty. Note: This is typically used in the Min Tubes approach, where all tubes do not have an associated CML.
  Button to automatically populate empty HX Overview.
• For the All Tubes approach, the HX Overview can be mapped directly:
  • Map each CML to a specific position on HX Overview:
    • Enter the coordinates (EVA row and EVA column in the CML grid). Note: In case of bulk import, these coordinates can be entered in the Excel template; or
    • Select a CML and click the direct map button on the HX Overview toolbar. Note: The button is only active when a CML is selected.
      Button to map CMLs directly to HX coordinates.

On the HX Overview:

• Yellow dots represent Unmapped tubes/CMLs.
• Green dots represent Mapped tubes/CMLs without measurement data.
• Blue dots represent Mapped tubes/ CMLs with measurement data.
  Two HX Overviews, one mapped and one unmapped.

Create a Measurement Set

A MS (Measurement Set) for the HX thickness measurements can be created in different ways:

• For the Min Tubes approach you can use the create and add button, on top of the Circuit details page.
  Create MS and add all CMLs.
• For the All Tubes approach it may be easier to create a MS manually with the MS button in the MS section of the Circuit details page. Note: It is possible that the PERF will be red. In this case, consider deactivating the CMLs not used.

If you want to create a MS for a specific stratum:

• Go to the EVA page. (See Doing an EVA.)
• Select a stratum and the CMLs will be filtered.
  Create MS.

  
  

• Export the filtered CMLs.
• Input this information into the MS Import template.

Populate the CMLs (with Inspection Data)

Do an inspection:

• Enter the inspection results directly in the MS in IMS; or
• Import the measurements into the MS:
  • First export the MS to fill it in.
  • If not yet done, set the Renewal Thickness and Nominal WT (at Service date) for all the CMLs with measurements.
  • Import back.

Buttons to Export and Import a MS.

•  Press the Calculate Measurement Set button.
  Calculate the MS.

  The data is now ready to be analyzed. See Doing an EVA.