Defining a catastrophic rupture scenario

Now that you have defined the Pressure Vessel, you can define any number of different Scenarios underneath it. The Catastrophic rupture Scenario is defined here first, as it has the simplest set of input data.

Inserting the Scenario

Select the Pressure Vessel node, and then insert a Catastrophic rupture Scenario using either the rightclick menu or the Insert gallery in the Home tab of the Ribbon Bar.

The Scenario node will be added to the Study Tree immediately, i.e. you do not have to place Scenarios on the GIS Input View, as Scenarios take their Geometry data (i.e.their location) from the Equipment item to which they belong.

You can leave the node with the default name of Catastrophic rupture. You will only be defining one Catastrophic Rupture Scenario for this Pressure Vessel so do not need to distinguish it from other Scenarios of the same type.

Setting the input data

The node will not be shown as incomplete when you insert it, as the Catastrophic rupture Scenario does not have any mandatory input fields. All of the fields take default values from the Pressure Vessel.

For this tutorial, you will edit the Scenario and set a non-default value for one field.

Elevation in Scenario tab section

The default value for the release Elevation is 1 m, but for the rupture you should set this to 7.37 m, which is the elevation of the centre of the sphere above the ground. You could have set the value of 7.37 m in the input data for the Pressure Vessel, but the other Scenarios will have different values for the Elevation, and to reduce the risk of confusion, the Pressure Vessel has been left with the default value of 1 m, and the Elevation is being set individually for each Scenario.

Toxic parameters tab section

If you look at this tab section, you will see that the value that you set in the Pressure Vessel dialog is present, and is shown as defaulted. The setting for the indoor toxic modelling is the same for all Scenarios for this Equipment item – as it is likely to be for most Equipment items – so it is appropriate to set the values at the Equipment item level.

Finally, click on OK to close the dialog.

Run the calculations for the Scenario and view the results

Select the Scenario and select Run from the Home tab of the Ribbon Bar.

Viewing the set of Graphs

When the calculations are complete, view the graphs for all of the Weathers. To do this, select the Scenario, then click on the Graphs option in the Home tab of the Ribbon Bar, and select all three Weathers in the Results Selection dialog.

You will see that there a Pool Vaporisation tab in the Graphs View, which shows that the liquid in the release did rain out; if you want more information about the behaviour of the liquid droplets in the cloud, you should view either the Commentary Report or the Dispersion Report.