Standardized lines representing the flow of energy, data, or materials.
Technical Overview: ISO 14617-3 — Graphical Symbols for Connections and Related Devices 0;16; 0;55d;0;a0f;
A quick Google search for will yield two types of results:

Standardized lines representing the flow of energy, data, or materials.
Technical Overview: ISO 14617-3 — Graphical Symbols for Connections and Related Devices 0;16; 0;55d;0;a0f; Iso 14617-3 Pdf
A quick Google search for will yield two types of results: Standardized lines representing the flow of energy, data,