Reading P&ID Symbols: A Step-by-Step Guide – GetReskilled

By: Donagh Fitzgerald and Gerry Creaner. Last Updated: February 2023

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What are P&IDs?

Piping and Instrumentation Diagrams (P&IDs) use a standardized set of symbols, notation and abbreviation to represent the various components of a process. These symbols are designed to be easily recognizable and convey important information about the component they represent. In this guide, we will walk through the basics of P&ID symbols, notation and abbreviation and how to read them.

Important

P&IDs are living documents, and it is important to keep them updated as the process changes over time. Practice is key to understanding P&ID symbols, notation and abbreviation, and interpreting them correctly.

Table of Contents

P&ID symbols can be broadly classified into 7 categories:

Piping Symbols

Examples include pipes, tubes, ducts, multi-line, separators, connectors, end caps, flanges, reducers, and coupling.

Reading P&ID Symbols: A Step-by-Step Guide - GetReskilled

Pipe

Reading P&ID Symbols: A Step-by-Step Guide - GetReskilled

Jacketed pipe

Reading P&ID Symbols: A Step-by-Step Guide - GetReskilled

Thermally insulated pipe

Reading P&ID Symbols: A Step-by-Step Guide - GetReskilled

Cooled or heated pipe

Reading P&ID Symbols: A Step-by-Step Guide - GetReskilled

Covered gas vent

Reading P&ID Symbols: A Step-by-Step Guide - GetReskilled

Curved gas vent

Reading P&ID Symbols: A Step-by-Step Guide - GetReskilled

Flange

Reading P&ID Symbols: A Step-by-Step Guide - GetReskilled

Butt weld

Reading P&ID Symbols: A Step-by-Step Guide - GetReskilled

Reducer

Reading P&ID Symbols: A Step-by-Step Guide - GetReskilled

Flexible hose

Reading P&ID Symbols: A Step-by-Step Guide - GetReskilled

Steam trap

Reading P&ID Symbols: A Step-by-Step Guide - GetReskilled

Viewing glass

Pump Symbols

Pumps are an essential part of the majority of industrial plants that need pumps. These pumps can be used for suction, compression, moving fluid, and also for pressure control. There are many p and id symbols for pumps.

Reading P&ID Symbols: A Step-by-Step Guide - GetReskilled

Pump

Reading P&ID Symbols: A Step-by-Step Guide - GetReskilled

Vacuum pump or compressor

Centrifugal pump

Gear pump

Screw pump

Screw pump

Vacuum pump

Reading P&ID Symbols: A Step-by-Step Guide - GetReskilled

Fan

Reading P&ID Symbols: A Step-by-Step Guide - GetReskilled

Axial Fan

Reading P&ID Symbols: A Step-by-Step Guide - GetReskilled

Radial Fan

Valve and Control Symbols

Represented by various shapes to indicate the type and function of the control device. Examples include valves, actuators, and controllers.

Reading P&ID Symbols: A Step-by-Step Guide - GetReskilled

Pressure reducing valve

Reading P&ID Symbols: A Step-by-Step Guide - GetReskilled

Valve

Reading P&ID Symbols: A Step-by-Step Guide - GetReskilled

Control valve

Reading P&ID Symbols: A Step-by-Step Guide - GetReskilled

Manual valve

Reading P&ID Symbols: A Step-by-Step Guide - GetReskilled

Needle valve

Reading P&ID Symbols: A Step-by-Step Guide - GetReskilled

Butterfly valve

Reading P&ID Symbols: A Step-by-Step Guide - GetReskilled

Ball valve

Reading P&ID Symbols: A Step-by-Step Guide - GetReskilled

Globe valve

Reading P&ID Symbols: A Step-by-Step Guide - GetReskilled

Diaphragm valve

Vessel Symbols

A vessel is used to store fluids or also be used to alter the characteristics of the fluid during storage. This includes tanks, cylinders, columns, bags.