15.16. Piping & instrumentation diagrams (P&IDs)
The P&ID, based on the PFD, represents the technical realization of a process by means of graphical symbols for equipment and piping together with graphical symbols for process measurement and control functions.
The Utility Flow Diagram (UFD) is a special type of a P&ID that represents the utility systems within a process plant, showing all lines and other means required for the transport, distribution, and collection of utilities. The process equipment in the UFD can be represented as a box with inscription (e.g. identification number) and with utility connections.