Understand Boundary elements

Start and end points of pipelines and stations can be specified using three types of Boundary elements: Branch Start/End, Boundary Object, and Station Inlet/Outlet.

Branch Start/End

Branch Start and Branch End are required elements in the model to specify the start and end of the pipeline at the Overview level as shown in the following illustration.

Note: If the model was migrated from SSPDraw, you might see Mainline Start/End instead of Branch Start/End because the branchType property is defaulted to "Mainline" (as opposed to "Branch"). The branchType property does not get imported into the Flow Network model in the RealTime database (RTDB). Therefore, its value has no bearing on the model.

Boundary Object

Boundary Objects are required at the Station level to specify if there is an entry point to the pipeline or an exit point from the pipeline through this station.

The first station in the pipeline must start with a Boundary Object. The last station in the pipeline must also end with a Boundary Object. Boundary Objects are also required when there is an entry point to the pipeline or exit point from the pipeline at the station.

The following example illustrates where Boundary Objects are required.

Consider the following pipeline configuration:

Station1 is the first station in the pipeline. Therefore, a Boundary Object b1 is placed at the beginning of the station.

Station2 has an exit point from the pipeline through valve V1 in the branching segment. Therefore, a Boundary Object B1 is placed at the end of that segment.

Station3 has an entry point to the pipeline through valve V2 in the merging segment. Therefore, a Boundary Object B2 is placed at the beginning of that segment.

This configuration requirement is used by the Line Blockage application to identify the boundaries of the pipeline.

Station Inlet/Outlet

The Station Inlet/Outlet represents the boundaries of the station itself. They connect the station to the pipeline and are therefore required in every station. In the previous example, notice how each station contains a Station Inlet and Station Outlet.

In Station2, Station Outlet o1 is placed at the end of the segment that connects Station2 to the pipeline.

In Station3, Station Inlet i1 is placed at the beginning of the segment that connects Station3 to the pipeline.