Nominal Pipe Size

Nominal Pipe Size (NPS) is a standardized system used in the United States and other countries to specify the diameter of pipes used in plumbing, heating, and other fluid systems. NPS provides a way to categorize pipes based on their approximate internal diameter, even though the actual measurements can vary. The nominal size is not an exact measurement of the pipe's dimensions; instead, it is a convenient way to identify pipes and fittings.