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.
diameter of the pipe
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.
with a bore gauge
Nominal bore which is designation for pipe size.
NB = Nominal Bore. Bore is the internal diameter of the pipe. The 50 is referring to 50mm (5cm). So it boils down to a pipe with an internal diameter of 50mm.
In Full bore ball valve, The bore dia will be same as internal dia of the pipe.In reduced bore, the bore dia is reduced than the ID of pipe.
Pipe with a Nominal Bore of 4 inch (100mm) Outside Diameter 114.3mm
the inner diameter of the pipe Nominal bore (NB) is 40 mm
The salt water rate that is flowing from a well bore, that has 600psi and 22 choke, through a 2inch pipe at the surface will only have as much force behind it as the pipe can hold. This will depend on what the pipe is made of, and what weight it is capable of.
It means 20mm Nominal Bore or 20mm inside diameter piping.