There is no relationship. NPS is based on inches.
bore of the pipe is the internal diameter of pipe but the nominal diameter of pipe is the dia of a circle which is draw through a point which is situates at exactly half of the thickness of pipe or we can say that (outer dia of pipe- thickness of pipe )=nominal bore of pipe.
The nominal bore of a pipe is its internal diameter. The nominal bore determines how much volume you have in the pipe to transport your particular substance.
Nominal bore which is designation for pipe size.
Measure the inside diameter and that is your nominal size.
Pipe bore is the actual minimum inside diameter of a pipe, which is not necessarily the nominal pipe size.
this is pipe size dn100 ( Diametre Nominal 100) =100A
The outside diameter (OD) of a 40-inch nominal bore black steel pipe is typically 40 inches, as the nominal size refers to the approximate internal diameter of the pipe. However, the actual OD for standard pipe sizes can vary; for a 40-inch nominal bore, the standard OD is approximately 42.16 inches according to the American National Standards Institute (ANSI) specifications. This discrepancy is due to the wall thickness of the pipe, which is accounted for in the nominal size.
In the context of flanges, "nb" typically refers to the nominal bore, which is the nominal diameter of a pipe or fitting. It indicates the internal diameter of the pipe and is used to standardize measurements for flanges, ensuring compatibility between different components in piping systems. The nominal bore is important for determining the appropriate size and type of flange needed for a specific application.
To find the outer diameter (OD) of a pipe ranging from 1 to 10 inches, you can refer to standard pipe size charts, which specify the OD for different nominal pipe sizes. For instance, a 1-inch nominal pipe typically has an OD of 1.315 inches, while a 10-inch nominal pipe has an OD of 10.750 inches. Additionally, you can measure the pipe directly using a caliper or tape measure if you have access to the physical pipe.
A 250 NP pipe is a pipe that is 250 millimeters in diameter and is 10 inches long. It comes in a variety of thicknesses. NB stands for nominal bore. Sometimes this is referred to as NPS which stands for nominal pipe size. NB is a standard for pipe sizes in North America.
The nominal pipe size is closest to the inside diameter; however, for exact calculations both should be looked up in a table based on the scheduled pipe size.
the inner diameter of the pipe Nominal bore (NB) is 40 mm