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Tanks with a Change of Density Between Cases

This analysis rule includes the list of tank elements that have a change in the density value between the current Case and the previous case. If the tank typically holds materials with a fluctuation in density, a threshold can be set for this tank to report only when outside of a normal range. A threshold of zero means that the rule has not been configured. The threshold must be greater then zero for the rule to run.

The following table lists a sample log output for this analysis.

Sample Log

TimeSeverityElementAttributeMessage
7/22/2005 13:15...REPORTING TANK WITH DENSITY CHANGE BETWEEN CASES
7/22/2005 13:15WarningTankATankA;Current Case: 30,Previous Case: 3.4,Difference: 26.6

Analysis Method​

  1. Collect a list of all tank elements in the current Case that satisfy the following criteria:
  • Status Attribute value is IS (In Service)

  1. For each tank, determine if the change of density is outside the allowable tolerance using the following test.

    Where:

    ρ = the density of the current case

    ρp = density of the previous case

    T = the density threshold

  2. Write to the log section of the case.

    Report the current Case density, the previous Case density and the difference between the two.

Configuration Using the Wizard​

The configuration of the Tanks with Change in Density Between Cases is a selection of the General Gross Error Analysis Rule. You open the window for configuring the test (shown in the following figure) from the General Gross Error Analysis Rule Wizard.

  1. Open the Gross Error Configuration window as described in Configuring - General Gross Error Analysis Rule.

  2. On the Tanks tab, select Tanks with a change of density between cases.

    A Tanks with change in density - Attributes window opens.Figure 372: Tanks with change in density - Attributes window

  3. Select Attributes according to the following table:

    Attributes

    SelectionsDescription
    DensityDensity of material in the tank. The default is 'Density'.
    ThresholdThreshold level for the change in the density, same units of measure as the density attribute, default to '0'.
    StatusTank in/out of service status. The default is 'ObjectStatus'.

  4. Select a threshold value (set initially to zero unless changed) for the difference in the density between the two cases.

  5. Click OK to finish the configuration.

    The text "CONFIGURED" displays next to the 'Tanks with a change of density between cases' selection.

  6. To run this test, see Running the General Gross Error Analysis.