There are two main international pipe flange standards, namely the European pipe flange system represented by German DIN (including the former Soviet Union) and the American pipe flange system represented by American ANSI pipe flanges. In addition, there are Japanese JIS pipe flanges, but they are generally only used for public works in petrochemical plants, and have little impact internationally. Now the pipe flanges of various countries are introduced
as follows:
1. European system pipe flanges represented by Germany and the former Soviet Union
2. American system pipe flange standards, represented by ANSI B16.5 and ANSI B 16.47
3. British and French pipe flange standards, both countries have two sleeve flange standards.
To sum up, the international common pipe flange standards can be summarized into two different and not interchangeable pipe flange systems: one is the European pipe flange system represented by Germany; the other is represented by the United States American pipe flange system.
IOS7005-1 is a standard promulgated by the International Organization for Standardization in 1992. This standard is actually a pipe flange standard that combines two series of pipe flanges from the United States and Germany [5].