Modular pipelines/tubes and corresponding equipment

Pipelines/pipes: Pieces with and without bolts, rivets

Connection pieces: T, r, X styles of connection pieces to create winding systems of piping, tubing etc

End Pieces: Taps, those wheels that can be opened or closed

Holding Pieces: Brackets and clamps to hold the tubes/pipelines

Instruments: Maybe watches showing pressure, with a connection piece to tubes/pipelines?