What is a Piping and Instrumentation Diagram (P&ID)
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.
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
Equipment
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.
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.
Vessels
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:
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.
Pumps
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.
Instruments
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.
Valves
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.
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.
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.
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.
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.
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.
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.
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| Factory System | Simple Process Control System | Juice and Nectar System |
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| 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.
Step 2: Drag and drop built-in symbols from the library. Alternatively, you can use a preset template to faster your work.
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.
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.
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.
