There are two systems in the international pipe flange standards, namely the European pipe flange system represented by DIN (including the former Soviet Union) and the American pipe flange system represented by ANSI. In addition, there are JIS pipe flanges in Japan, but they are generally only used for public works in petrochemical plants, and have little international influence.
1. European system pipe flange represented by Germany and the former Soviet Union
2. American system pipe flange standard, represented by ANSI B16.5 and ANSI B 16.47
3. British and French pipe flange standards, each of which has two casing flange standards.
To sum up, the international general pipe flange standards can be summarized as two different and non interchangeable pipe flange systems: one is the European pipe flange system represented by Germany; the other is the American pipe flange system represented by the United States.
