Lifetime Estimator Editor

The Lifetime Estimator Editor is used to carry out a statistical analysis on pipe failure data in order to estimate pipe expected lifetime and likelihood of failure for different classes of pipe.

To open the editor for use with a network, drag the Lifetime Estimator onto the network. Pipe failure data can be collected from the network and network pipe data can be updated from estimator results.

See the Lifetime Estimator topic for further details.

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Lifetime estimator parameter Description
Pipe Class dropdown

List of pipe classes populated by use of the following buttons:

  • Add - adds a pipe class to the editor. To add a class, enter the Pipe class in the dropdown box and click the Add button
  • Remove -removes the currently displayed pipe class from the editor
  • Refresh - searches for pipe classes in the network. Classes not already present in the editor will be added. (This button is enabled when the Lifetime Estimator is associated with a network)
Use incident data for lifetimes

Choose this option to use incident data in the calculation of failure times when the Get lifetimes button is clicked.

Collapse incident data is used for Collection networks and burst incident data for Distribution networks.
Use condition data for lifetimes

Applicable to Collection networks only.

Choose this option to include CCTV survey structural grade data in the calculation of failure times when the Get lifetimes button is clicked. A pipe with CCTV survey with Structural grade or Structural override grade >= 5 is considered a failure.
Get lifetimes button

The Get lifetimes button is enabled when the Lifetime Estimator is associated with a network.

Click this button to calculate failure and survival times for pipes in the currently displayed class.
Failure time grid

List of the age at failure of all failed pipes in the network in the current pipe class.

The list may be generated from the network by using the Get lifetimes button, or may be edited manually.
Survival time grid

List of the age of all pipes in the network in the current pipe class that have not failed.

The list may be generated from the network by using the Get lifetimes button, or may be edited manually.
Likelihood of failure estimation

The Likelihood of failure estimation group displays the Expected lifetime of pipes in the currently displayed pipe class and a grid of likelihood of failure values.

Records may be added/removed from the grid using the +/- buttons.

Column Description
Likelihood

Likelihood score value used to populate the Likelihood score data field when the Update pipes button is clicked.
%

Percentage probability of failure when Use % probability of failure option is selected.

Percentage of expected lifetime when Use % of expected lifetime option is selected.

Percentage values may be edited (unless using the Fixed age boundaries option). Age values will automatically be calculated from the defined percentage values and the probability curve.
Age

The age displayed depends on the failure estimation option selected:

  • Fixed age boundaries - age is set to a fixed user defined value
  • Use % probability of failure - age at which percentage of pipes will fail; calculated from probability curve.
  • Use % of expected lifetime - age calculated as percentage of expected lifetime; calculated from probability curve
Cumulative failure probability graph

Displays the fitted curve of probability of failure as a function of time for the currently displayed pipe class.

Regions on the graph with different likelihood values are plotted as red lines according to the options selected in the Likelihood of failure estimation group.
Fit Curve button Click this button to generate a fitted curve using the values in the Failure time and Survival time grids for the currently displayed pipe class.
Fit All Classes button

The Fit All Classes button is enabled when the Lifetime Estimator is associated with a network.

Click this button to generate fitted curves for all pipe classes in the editor.

Failure time and survival time data is taken from the associated network.
Flag dropdown Select a flag to be applied to fields updated in the network when the Update Pipes button is clicked.
Update Pipes button

The Update Pipes button is enabled when the Lifetime Estimator is associated with a network.

Click this button to update pipe Expected lifetime and Likelihood score fields that do not already have a value. The fields will be updated according to the values displayed in the Likelihood of failure estimation group for each pipe class.
Save button Click this button to save changes made to the editor.

Lifetime Estimator