From Object Structure

A pipe system is the same as a pipeline in a facility and main equipment like column, heat exchanger, reactor, pressure vessel or pump is entered as from-object for this pipe system. It is usually not recommended to enter from-object relations on secondary equipment (valves, ventilation, drains, measuring equipment and so on) on detailed pipe segments. It's more common to be used for main equipment and pipe systems. This enables work and preventive maintenance to be monitored and planned by using main equipment and all pipe lines that are leaving from it. For example, monitor and plan all work for a pressure vessel and pipe lines that are leaving from the pressure vessel.
This structure could be created in two different ways: