What does NPT stand for in piping contexts?

• A. National Piping Thread
• B. National Pipe Thread
• C. New Pipe Thread
• D. Noble Pipe Tap

Answer: (B)

Understanding pipe thread terminology is essential. NPT refers to a standardized thread form used on pipes and fittings to create a seal when assembled. The common interpretation of the acronym is National Pipe Thread, indicating a national standard for pipe threads. This naming reflects a unified standard for pipe threads so fittings from different manufacturers can mate reliably. In some texts you’ll also see National Pipe Tapered Thread mentioned, which notes the taper that helps seal, but the shorthand NPT most often corresponds to National Pipe Thread. The other options don’t fit because they aren’t the recognized term used for this piping thread standard.