ASME B31.3 primarily covers:

• A. Instrumentation piping
• B. Heating piping
• C. Nuclear piping
• D. Process piping

Answer: (D)

ASME B31.3 is the code that governs piping systems used to convey process fluids in processing plants. It sets the requirements for design, materials, fabrication, erection, testing, and inspection to ensure safe operation of these process piping systems found in chemical plants, refineries, pharmaceuticals, and similar facilities.

That’s why the best choice is process piping: the code is specifically titled and scoped for process piping, not for instrumentation lines, heating piping (which is more commonly associated with other piping codes in practice), and not nuclear piping (which falls under different sections of the ASME Codes). In short, B31.3 focuses on piping that handles process streams in processing industries.