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What is a Piping and Instrumentation Diagram (P&ID)

> Edraw Knowledge > What is a Piping and Instrumentation Diagram (P&ID)
Posted by Janice | 01/14/2021

Part 1: What is a P&ID?

A piping and instrumentation diagram displays the piping components (for example equipment, valves, reducers and so on) of an actual physical process flow and is often used in the engineering projects, such as setting up steam boilers, heat exchangers, electric boilers and more.

To read a piping and instrumentation diagram, simply break down the overall diagram into smaller parts and then trace from a single equipment and follow the pipeline. Piping and instrumentation diagram also has a close relationship with the Process Flow Diagram (PFD). The latter type shows a picture of the separate steps of a process in sequential order.

Main purpose of using piping and instrumentation diagrams are:

  • To better understand the design conditions of an engineering project;
  • To operate, maintain and modify the process system efficiently;
  • To conveniently layout out and demonstrate the physical sequence of systems with the focus on the control and shutdown schemes, safety and regulatory requirements, and the basic start-up and operational details.

piping and instrumentation diagram template

Part 2: P&ID Elements

There is no standard pattern for a piping and instrumentation diagram, but you may see some of the following elements:

  • Different kinds of equipment, including valves, reducers, drains and so on;
  • Equipment details such as sizes, tag numbers, rating, capacity and more;
  • Details about the specifications, including element identification, insulation requirement, flow directions, interconnections reference, quality level, various interfaces, permanent start-up, and flush lines.

Part 3: Usages of P&IDs

Piping and instrumentation diagrams have been used in many fields such as metallurgical sector, air conditioning industry, power generator sectors and so on. The key usages of such diagrams are:

  • For designing a manufacturing process for a physical plant with complex chemical or mechanical steps. This is especially important for a safety check.
  • For training new workers and contractors before they start work in the plant.
  • To derive project capital cost estimate and develop project contract specification, for example, the guidelines and standards for facility operations.

Part 4: P&ID Symbols


The equipment has unique miscellaneous units that are different from the other piping and instrumentation diagram categories. The equipment category contains facilities and devices such as compressors, conveyors, motors, turbines, vacuums, and more.

pid symbols - equipment

Piping and Connection Shapes

Pipes are used to transporting fluid substances in industrial diagramming. Piping has several different materials, such as metal and plastic, to create various types, including multi-line pipes, separators, and so on.

pid piping symbols


Normally, a vessel is a kind of container used to store fluid or change the fluid features during storage. The vessels category covers from tanks to columns as you can see below:

vessels pid symbols

Heat Exchangers

A heat exchanger is used to transfer heat from various kinds of areas or mediums efficiently. This category includes many different forms of devices such as boilers, condensers, hose reels, and more.

heat exchangers


Generally, a pump is a kind of device that uses pressure to raise or compress fluids in and out of other industrial facilities. This category covers pumps, fans, ejectors, sprays, and more.

pumps pid symbols


An instrument is used to measure and control quantities, including flow, temperature, or pressure. The instruments category includes house indicators, transmitters, weir meter, controllers, and so on.

instruments pid symbols


A valve is used by engineers to control the flow of a fluid by opening or closing passageways in a piping system. This section includes rotameters, gauges, balls, and more.

valves pid symbols

Part 5: Free P&ID Templates

Water Boiling Process

This example here shows a general process for changing from the liquid phase to a gaseous phase. In this case, the liquid's vapor pressure has the same level as the atmospheric pressure exerted on the liquid.

water boiling process pid example

Power Generation System

A power generation system, which is also called a power plant or power generation station, is a set of industrial equipment for generating electric power. You can see different facilities, such as power supply tanks and LP turbines, in the following diagram.

power generation p&id example

Evaporate Process

This diagram here shows an evaporator system with some elements and three key evaporators. By following the pipelines in this diagram, you can clearly see how water is evaporated.

evaporate process p&id example

Air Conditioning System

This piping and instrumentation diagram example here shows the general process of removing heat and moisture from a certain space to improve the living environment. The key air conditioner is set at the middle and equipped with pipelines in different directions.

air conditioning p&id example

Low Dust SCR System

SCR refers to the Selective Catalytic Reduction, which is an advanced emissions control system. Hit the diagram below to check out more details, or you can free download it in PDF format.

low dust scr system example

Here are more piping and instrumentation diagram templates for you to easily understand the field. All of these are editable with a free download piping and instrumentation diagram software. Feel free to click on any of them to see more details.

factory pid example simple process control system example juice and nectar pid example
Factory System Simple Process Control System Juice and Nectar System
grain logistics pfd example grain storage dryin example protein skimmer pid example
Grain Logistics PFD Example Grain Storage Drying Protein Skimmer Example

Part 6: How to Create a P&ID

Step 1: Launch EdrawMax on your cpmputer. Navigate to [Industrial Engineering] and open a P&ID example.

open edrawmax

Step 2: Drag and drop built-in symbols from the library. Alternatively, you can use a preset template to faster your work.

drag and drop p&id shapes

Step 3: Connect piping and instrumentation diagram shapes and equipment with pipelines in different directions. Adjust the length and width of a pipeline according to your specific needs. Also, keep in mind that some equipment may require special configuration.

connect p&id shapes

Step 4: Customize your piping and instrumentation shapes by changing the default color and size. You can further add text to or label each of the equipment.

edit p&id shapes

Step 5: When your P&ID is complete, you can export it to JPG, PNG, SVG, PDF, Microsoft Word, Excel, PowerPoint, Visio, HTML with just a single click. So you can share your drawings with people who don't use EdrawMax with no need to looking for ways of converting file formats.

save and export file in EdrawMax

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Video Tutorial - How to Create a P&ID

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Get Started! You Will Love This Easy-To-Use Diagram Software

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