Calculating Event Tree Results
Calculating event tree results consists of making the appropriate selections and then starting the process.
1. For each event, right-click and select View Column Properties to open its Event Properties window. Then, ensure that calculation data is entered under Input type. For more information, see General Page.
2. For each terminating branch, right-click and select View Branch Properties to open its Branch Properties window. Then, ensure that consequences are assigned on its Consequences page. For more information, see Consequences Page (Terminating Branch Only).
3. To open the Calculate window, do one of the following:
On the standard toolbar, click Calculate.
Select System > Calculate.
Press F8.
4. On the Calculation Selection page, select Event Tree. If this checkbox is cleared, event tree calculations do not run.
5. Complete the Event Tree page. For qualitative analysis, be sure to select the Cut Sets checkbox. For more information, see Event Tree Calculate Property Page.
6. After entering any additional data for other calculations to perform, click OK to run the requested calculations.
The calculation data for any columns or branches that are linked to other items in the System file are first updated. Changes made to events inserted in the calculation from an FTA Event Library file are also recognized and used.
The Calculation Progress opens, displaying progress as the requested calculations run. When the calculations finish, the View Calculation Results window opens. If calculations for multiple modules are performed, event tree calculation results appear on the Event Tree Results page.
At the top of the window, results for the primary time point are shown for each event and branch in the Event Tree Columns and Event Tree Results tables, which are described in Event Tree Column and Branch Results. In the table, results at each of the primary time points are available for the consequence selected for Results for consequences.
To view the results for a different consequence, you choose a different consequence in this field. If you selected Calculate consequences across all Event Tree diagrams on the Event Tree page in the Calculate window, the values shown are the consequence results over all event trees. In this case, the result values are computed by taking into account the weight factor assigned to event tree and summing the weighted results across all event trees.
At the bottom of the page are Excel and Print buttons, which you can use to save table results to a Microsoft Excel spreadsheet or to print them to a printer. For more information, see Excel and Print Buttons.
7. When finished viewing results, click Close.
You can view these same calculation results again at any time. To do so, select System > View Calculation Results.