A Pipe Size is a pipe nominal diameter and pipe wall thickness in which a standard pipe size is defined below two ways: 1) American NPS (Nominal Pipe Size) or NB (Nominal Bore) system: A Pipe Size is specified in ANSI, ASME and API standards, and using an imperial unit, 2) European DN (Nominal Diameter) system using a metric unit (millimetres). A standard tube size is referred to an outside diameter (OD).

Related Definitions in the Project: The Piping and Pipeline Engineering