In the Study Tree, rename the node to Chlorine, Saturated 10 degC.

Setting the input data for the vessel

The Pressure Vessel node will have a red error icon at the top left, indicating that it does not have a full set of input data. You will not be able to run the consequence calculations for any Scenarios under the Pressure Vessel until you have supplied values for all of the mandatory input fields, as described below.

Double-click on the icon for the Pressure Vessel to open the input dialog.

Most of the fields in the first tab section will be blank, and those that are enabled will have red borders and error icons. A field with a red border is a mandatory field: you must supply a value for such a field if it is enabled, and you will not be able to run the calculations for Equipment items or Scenarios that have any mandatory fields unset.

This section describes each tab section in turn, including those that are not relevant to this particular hazardous event. Click on the Help button in the dialog to open the online Help if you want further information at any point.

The Material tab section

To set the Material, select CHLORINE from the dropdown list of all of the materials that are defined in the System Materials.

The vessel is a sphere with a volume of 120 m3. This Equipment item will represent the vessel with the maximum degree of filling, which is 85%. Check the Specify volume inventory? box to select this method of specifying the inventory instead of giving the mass and enter a value of 102 m3 in the

Volume inventory field.

The chlorine is held under saturation conditions at atmospheric temperature. The temperature will vary depending on the season and time of day, but for this Equipment item a value of 10oC will be used as representative. To set these process conditions, set the Specified condition to Temperature/bubble point and set the Temperature to 10 degC, as shown below. When you move the cursor away from the Temperature field the program will calculate the saturation pressure for this temperature and display it in the Pressure field.

To define the process conditions for a material that is not held under saturation conditions (e.g. a gas or a padded liquid), you must set the Specified condition to Pressure/temperature and give values for both.

The Toxic parameters tab section

The fields in this tab section are used in modelling the toxic effects for people indoors, in buildings in the path of the dispersing cloud.

By default, these calculations are not performed, but for this tutorial you should turn them on by checking the option to Specify the downwind building type. The calculations require information about the ventilation-rate for the representative building and about how long people remain in the building after the cloud has passed and the concentration is lower outdoors than indoors, This information is defined using the Building Type nodes in the Map tab section of the Study Tree. The new workspace is created with one Building Type called “Building type” already defined, with the ventilation value and evacuation values set to the defaults.

This default Building Type is selected by default, and for this tutorial you should leave the Building type field with this default setting, as shown.

The Geometry tab section

Set the East co-ordinate to 198492 m, and the North co-ordinate to 435063 m.

A Summary of the Input Data

The dialog includes a large number of input fields, but the number of values that you have to enter in order to complete the data for this Pressure Vessel is very small, as shown in the table below:

Make sure you have set all of these values correctly, and then click on OK to close the dialog.