The inside diameters under IPS were roughly the same as the more modern Ductile Iron Pipe Standard (DIPS) and Nominal Pipe Size (NPS) Standards, and some of the wall thicknesses were also retained with a different designator.
The inside diameters in IPS standards were roughly comparable to those found in the modern Ductile Iron Pipe Standard (DIPS) and Nominal Pipe Size (NPS) Standards, and certain wall thicknesses were maintained using a distinct identifier.