What is the difference between nb and dn

The outer diameter and the inner diameter are better understood. Others such as reinforced concrete pipe, cast iron pipe, galvanized steel pipe, etc. Generally, the nominal diameter is used in the design drawings. The nominal diameter is a standard that is artificially specified for the convenience of designing and manufacturing, and also a nominal diameter, is the specification name of the pipe or pipe fitting.

The nominal diameter of the pipe is not equal to the inner diameter and outer diameter. It can also be said that the nominal diameter is close to the inner diameter, but not equal to the inner diameter.

The name of a pipe diameter specification, in the design drawings, the nominal diameter is used. Specific pipe is identified by pipe diameter and another non-dimensional number for wall thickness referred to as the Schedule SCH.

Pipe schedule sets the pipe wall thickness. Increasing the wall thickness of the pipe increases the mechanical strength of the pipe, allowing it to handle higher design pressures. However with the advancement of industrial age and use of pipes in varying pressure and temperature conditions, these three sizes did not fit all applications. There have been many revisions and additions to the tables of pipe sizes based on industry use and on standards from API, ASTM, and others.

Today we have a range of wall thicknesses, namely:. Stainless steel pipes, due to less risk of failure due to non-corrosive property, permitted the use of pipes with thinner wall thickness. Stainless steel pipes are most often available in standard weight sizes noted by the S designation; for example, Sch 10S. However stainless steel pipe can also be available in other schedules. Pipes are available in many DN sizes and the DN is used to finalize the pipe dimensions with standard tables and pipe schedule charts.

The actual Inner diameter of pipe from different manufacturers can deviate by several millimeters and such type of pipe can be weld together if DN is indicated with reference standards.

Nominal bore or NB is a European standard for Pipe size indication. In the case of pipes, Bore means a hollow structure and nominal is for approximate. The nominal bore is actually the approximate internal measurement of the pipe across its diameter.

In other words, a Nominal bore refers to the approximate size of the bore of the pipe. When a pipe is measured in inches, NB pipe turns out to be exactly This is the reason why outside diameter is not that simple number like NB. There is some standard that must be followed by manufacturers to select outside diameter of the pipe. Be careful…!!! In the case of a 3-inch pipe, its nominal bore will not be 75mm but it will be denoted with 80NB.

Yet many features are similar of NPS, NB, and DN but there is few obvious difference that we should keep in mind during using these notations:.