NPS refers to?

• A. National Pipe Size
• B. Normal Pressure System
• C. Non-Pressurized Size
• D. Nominal Pipe Size

Answer: (D)

NPS stands for Nominal Pipe Size, a designation used in North American piping standards to indicate the size category of a pipe. It is a nominal reference, not the exact measured diameter. The outside diameter of a pipe is fixed for each NPS and the inside diameter depends on the wall thickness or schedule, so the same nominal size can have different actual IDs. This convention lets engineers and purchasers match pipes, valves, and fittings from different manufacturers consistently across a project. The other options aren’t standard terms used to designate pipe size, so the intended meaning here is Nominal Pipe Size.