What is a P&ID symbol?
A P&ID (Piping and Instrumentation Diagram) symbol is a standardized graphic that represents a piece of equipment, a valve, an instrument, or a line type on a process drawing, so that any engineer reading the diagram — regardless of company or country — understands what it means. This finder covers 385+ symbols across pumps, valves, heat exchangers, vessels and tanks, oil & gas upstream equipment, pharmaceutical/biotech equipment, rotating equipment, mixers and agitators, piping specialties, instruments, interlock and logic elements, signal and process lines, valve actuators, and motors and drivers.
Symbols are drawn to two conventions: ANSI/ISA-5.1, the standard most commonly used for instrument and valve symbols and instrument tag abbreviations in North American plants, and ISO 10628 or common industry practice, typically used for major equipment items like vessels, exchangers, and rotating machinery. Every symbol card shows which convention it follows so you can stay consistent across a drawing set.
Frequently asked questions
What is a P&ID symbol used for?
A P&ID symbol represents equipment, valves, instruments, or line types on a Piping and Instrumentation Diagram, giving every engineer, operator, and contractor a shared visual language for how a process plant is built and controlled.
What's the difference between ANSI/ISA-5.1 and ISO 10628 symbols?
ANSI/ISA-5.1 is the standard most often used for instrument and valve symbols and instrument tag abbreviations, especially in North America. ISO 10628 (or common industry practice) is typically used for major equipment items such as vessels, heat exchangers, and rotating machinery. Many plants mix both within the same drawing set.
Can I download P&ID symbols as vector files?
Yes — every symbol on this page can be exported as a transparent PNG, a white-background JPG, or a vector SVG, ready to drop into Visio, AutoCAD, SmartPlant, or Excel.
How do I find a symbol quickly?
Type any part of the name, tag, or alias into the search box — it's a true substring search, so typing "cool" finds every air-cooled and water-cooled exchanger, and typing a tag like "PSV" or "FT" jumps straight to that instrument.
What do the instrument tag letters (like FT, PSV, LIC) mean?
Those are ISA-5.1 instrument identification letters — the first letter is the measured variable (F = flow, P = pressure, L = level, T = temperature) and the following letters describe the function (T = transmitter, I = indicator, C = controller, SV = safety valve). Use the "Tag Codes" button above the grid to look up any combination.
Is this P&ID symbol library free to use?
Yes, the full library of 385+ symbols, the tag abbreviation lookup, and the pipe schedule reference are free to use with no signup required.