PI Diagram (Piping and Instrumentation Diagram)

A Piping and Instrumentation Diagram (PI Diagram or P&ID) is a detailed schematic representation used in process engineering to illustrate the piping layout, instrumentation, and control systems within an industrial process. It shows how components such as valves, pumps, sensors, and controllers are interconnected, providing both a functional overview and essential reference for design, operation, and maintenance.

PI Diagrams are critical for the safe and efficient design, commissioning, and troubleshooting of complex systems in industries such as energy, chemical processing, water treatment, and manufacturing. They form the backbone of process documentation and are used across disciplines for planning automation systems, verifying compliance with safety regulations, and coordinating engineering workflows.

Standardised symbols are used to ensure clarity and interoperability, and the diagrams are typically maintained and updated throughout the asset lifecycle.

See also: Building Information Modeling, Digitalisation on Industrial Environment