Which statement about P&ID diagrams is true?

• A. They only show piping routes
• B. They are used for electrical wiring diagrams
• C. They depict instrumentation wiring diagrams
• D. They can contain multiple loops and show physical connections

Answer: (D)

P&ID diagrams illustrate the process flow with piping, equipment, valves, and instrumentation, along with how those instruments are interconnected to form control loops and how devices are physically connected in the plant. Because of this, a P&ID can contain multiple loops representing different parts of the process and their control strategies, and it shows the physical connections between components such as taps, instruments, and lines. This makes the statement about multiple loops and physical connections the best fit.

The other options don’t fit because P&IDs are not limited to piping routes, they aren’t electrical wiring diagrams, and while they include instrumentation, they don’t provide a detailed electrical wiring schematic.