Which diagram is specifically used to show piping and instrumentation in a plant?

• A. P&ID
• B. Isometric
• C. Layout plan
• D. Flowchart

Answer: (A)

Piping and Instrumentation Diagram is used to show piping and instrumentation in a plant. This diagram maps the actual piping routes, valves, equipment (like vessels and pumps), and all instruments and control devices, along with their interconnections and tag numbers. It’s the detailed blueprint engineers rely on for design, construction, operation, and maintenance, showing how streams flow through the system and how each instrument and control loop fits into the process.

In contrast, an isometric provides a 3D representation of pipe runs for fabrication and installation, a layout plan shows the physical placement of equipment in a space without detailing the piping and instrumentation, and a flowchart outlines the sequence of processing steps rather than the plant’s physical piping and control elements.