P&ID Symbols and Notation


Like other specialized diagrams, P&ID's are comprised of standard shapes and symbols. There's a huge variety of symbols, depending on industry and manufacturer, so we've created this guide to feature the most popular P&ID symbols supported within our P&ID software and is standardized for best practice across the industry.

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About P&ID symbols

Piping and instrumentation diagrams, or P&IDs, are used to create important documentation for process industry facilities. The shapes in this legend are representative of the functional relationship between piping, instrumentation, and system equipment units. We've broken them down into seven main groups: equipment, piping, vessels, heat exchangers, pumps, instruments, and valves.

With Lucidchart, it's easy to access all of the featured P&ID symbols. Users can also import SVG and other image files to create a custom P&ID library for any situation.

Equipment symbols

Equipment is comprised of miscellaneous P&ID units that don't fit into the other categories. This group includes hardware like compressors, conveyors, motors, turbines, vacuums, and other mechanical devices.

P&ID symbols

Piping symbols

A pipe is a tube that transports fluid substances. Piping can be made of various materials, including metal and plastic. The piping group is made up of one-to-many pipes, multi-line pipes, separators, and other types of piping devices.

piping P&ID symbol

Vessel symbols

A vessel is a container that is used to store fluid. It may also alter the characteristics of the fluid during storage. The vessels category includes tanks, cylinders, columns, bags, and other vessels.

vessel P&ID symbols

Heat exchanger symbols

A heat exchanger is a device that's designed to efficiently transfer heat from different areas or mediums. This category includes boilers, condensers, and other heat exchangers.

heat exchanger P&ID symbols

Pump symbols

A pump is a device that uses suction or pressure to raise, compress, or move fluids in and out of other objects. This section is comprised of both pumps and fans.

pump P&ID symbols

Instrument symbols

An instrument is a device that measures—and sometimes controls—quantities such as flow, temperature, angle, or pressure. The instruments group houses indicators, transmitters, recordings, controllers, and elements.

instrument P&ID symbols

Valve symbols

A valve regulates, directs, or controls the flow of a fluid by opening, closing, or partially obstructing passageways in a piping system.This category includes rotameters, orifices, and other types of valves.

valve P&ID symbol