Home » Instrumentation Symbols Legend

Instrumentation Symbols Legend

Process and Instrumentation Diagrams use special shapes to represent different types of equipment’s, valves, instruments and pipelines.


Piping and Instrumentation Diagrams (P&IDs) use specific symbols to show the connectivity of equipment, sensors, and valves in a control system. These symbols can represent actuators, sensors, and controllers and may be apparent in most, if not all, system diagrams. P&IDs provide more detail than a process flow diagram with the exception of the parameters, i.e. temperature, pressure, and flow values. “Process equipment, valves, instruments and pipe lines are tagged with unique identification codes.

Common P&ID Symbols Legend

Piping and instrumentation diagrams, or P&IDs, are used to create important documentation for process industry facilities. The shapes in this legend are representative of the functional relationship between piping, instrumentation, and system equipment units. We’ve broken them down into seven main groups: equipment, piping, vessels, heat exchangers, pumps, instruments, and valves.

Similar Articles:

Related Articles

How a 4-20mA Transmitter Works ?

S Bharadwaj Reddy


S Bharadwaj Reddy


S Bharadwaj Reddy

Transmitters 4-20mA Current Failure Alarm Limits

S Bharadwaj Reddy

Sink or Source? PNP or NPN? Normally Open or Normally Closed?

S Bharadwaj Reddy

Understanding a Process Control Loop

S Bharadwaj Reddy

1 comment

Nyl August 7, 2015 at 11:39 pm

Great sources. No doubt, you’re an authority in the industry.


Leave a Comment

This website uses cookies to improve your experience. We'll assume you're ok with this, but you can opt-out if you wish. Accept Read More

WordPress Image Lightbox