For this tutorial, you should leave the Safety system modelling (isolation and blowdown) option with the default value of No, which means that the inventory is assumed to be isolated immediately, at the start of the release, and blowdown is not considered.

These are the only changes you need to make to the Pressure vessel data, so you can click on OK to close the dialog.

Setting the input data for the Scenario

The new Scenario will be shown as incomplete, as this type of Scenario does have mandatory data.

Open the input dialog and set the input data as follows:

Scenario tab section

Make sure the Scenario type is set to Line rupture (rather than Disc rupture or Relief valve).

Set the Pipe internal diameter to 25.4 mm, the Pipe length to 9 m, the Release height from vessel bottom to 0 m, and the Elevation to 0.1 m. With this value for Elevation, the liquid droplets will probably not evaporate inside the cloud, and will probably rain out and form a vaporising pool.

Note: the Pipe internal diameter is 1 inch, and the easiest way to set this is to type “1 in” in the input field and press [Tab]. The program recognises “in” as a defined unit for length, and will convert it to the default display units of mm when you press [Tab] or click in a different field.

The Scenario tab includes the Outdoor release direction field, which you should leave with the default value of Horizontal, which is the correct setting for this type of unobstructed rupture of horizontal pipework.

The list of directions includes a second horizontal option: Horizontal Impingement. You should select this option if the release is in a congested area and the release is likely to impinge on a wall or other equipment; the program will reduce the momentum of the release, which will reduce the amount of air mixed into the jet during the initial stages.