Which length is the nominal size of the flange? What is the nominal diameter of the pipe?
The nominal size of flanges does not represent the size of any flanges, only the specifications of the flange. The specific dimensions should be referenced by the flange standard. For example, DN100 doesn't mean that the diameter of the flange is 100 depending on the pressure of the flanges, the size of the standard. The diameter of the pipe is not a specific size, the size of the pipe shall be measured according to the number of pipes. DN: the size of the letter and number of the elements of the piping system. DN and it consists of letters followed by dimensionless integer Numbers. The Numbers with end fittings aperture or outside diameter (mm) is directly related to the characteristics such as size. Note 1: in addition to the relevant standards, the Numbers behind the letter DN do not represent measurements and are not used for calculating purposes. Note 2: the standard of the DN identification system should be given the relation of the DN to the size of the pipe element, such as DN/OD or DN/ID.
The nominal size of flanges does not represent any flanges and the size of the flanges is only specified by the flange standard! For example, DN100 doesn't mean that the diameter of the flange is 100 depending on the pressure of the flanges, the size of the standard.
Also the nominal diameter of the pipe is not specific to the size of the pipe The industrial parameters, combined with the official name, do not mean the exact size means a level. The exact dimensions should be examined for the corresponding criteria
