Jun 10, 2016 · P&ID is the acronym for “Piping and instrumentation diagram”, i.e. a very detailed diagram showing the processes happening within a plant, the involved equipment, and their interconnections. A set of standardized P&ID symbols is used by process engineers to draft such diagrams. P&ID symbols exist for all major components and lines, such as valves, vessels, instruments, pumps, compressors, and towers. The ISA S5.1, ISO 10628, and BS 5070 cover the standardization of P&ID symbols …