How to Draw a P&ID Diagram

To draw a piping and instrumentation diagram, you’ll need a basic understanding of what a P&ID is. You may want to review a P&ID symbols legend to ensure that you’re using the correct shapes in an appropriate context. When you have the right tools on hand, it’s time to begin.

For the purposes of this guide, we’ll proceed as though you’re using Lucidchart. Lucidchart was created with P&ID diagrams in mind, so creating a useful diagram will be incredibly easy. Get started with a free Lucidchart account.

1. List equipment

Remember that P&IDs represent the hardware and software necessary to design, build, and run a process industry facility. To create such a comprehensive design, start by listing the elements in a standard P&ID. Your list should include all piping elements, including the order and placement of:

• Branches

• Control interlocks

• Equipment

• Instrumentation

• Reducers

• Valves

2. Add shapes

In your new Lucidchart account, open up a new document. You may need to enable the the Process Engineering shape library by clicking on the “Shapes” button on the upper left corner of your browser. Find the Process Engineering option and make sure the box has been checked.

Once the P&ID shapes are available to you, simply drag the necessary shapes onto the canvas and configure them by clicking the context panel icon that appears next to the shape. A variety of options appear here; for example, a tank can be customized with various roof types, and users can toggle between hiding and showing the stump. If you get lost in the vast array of P&ID shapes, use the toolbox’s search function to find a specific symbol.

3. Connect pipes and equipment

Now that you’ve assembled the components, connect them to each other in the appropriate order. In Lucidchart, each shape snaps cleanly to a connecting line or pipe. If you’re not sure how the process ought to flow, ask yourself:

• Which action triggers this process?

• What happens next?

• To move onto the next step, what equipment do I need?

• Does this unit require special configuration?

All of Lucidchart’s P&ID shapes and options are based on the ISA S5 standards. Within the application, they are categorized according to the following groups (which do not constitute a comprehensive list):

Equipment

• Compressors

• Conveyors

• Motors

• Turbines

Piping

• One-to-many pipes

• Multi-line pipes

• Separators

• Reducers

• Flanges

Vessels

• Vessels

• Tanks

• Cylinders

• Columns

• Bags

Heat exchangers

• Boilers

• Condensers

• Exchangers

Pumps

• Pumps

• Fans

Instruments

• Indicators

• Transmitters

• Recordings

• Controllers

• Elements

Valves

• Valves

• Rotameters

• Orifices