Main node for standard shaft or structure

Depending on the detail or accuracy of the documentation: a fictitious point that can be defined as an integral point for the inlet/outlet of a standard shaft. It represents the point where the various lines meet in the shaft. 

In more detailed shaft documentation with inlets and outlets, it can be used as an additional point for the sole. It is the lower boundary surface (and thus the lowest point) of a shaft or structure.

Inlet

The inlet represents the handover point from a pipeline to a plant structure, i.e., the 'entrance' to a plant structure such as a basin, shaft, or other structure. (Source: Internal SEW documents)

Outlet

The outlet represents the handover point from a plant to a pipeline construction, i.e., the 'outlet' from a plant structure such as a basin. (Source: Internal SEW documents)