The main pipe located at the center of the system layout is called what?

• A. Distribution main
• B. Service main
• C. Suction main
• D. Return main

Answer: (A)

In piping systems, the central trunk that carries the main flow and distributes it to branches is called the distribution main. It sits at or near the center of the layout to act as the backbone, feeding out to service lines that supply individual areas or equipment. The service main feeds specific points from that backbone, the suction main is the pump’s intake line, and the return main collects fluid to return it to a reservoir or sump. So the central, primary conduit described is the distribution main.