What are the standards for copper pipes and fittings

What are the standards for copper pipes and fittings? There is a big difference between the current national standard and the original national standard. The new standard basically refers to the European and American standards, and stipulates that the wall thickness of DN 15 ~ 200 mm can be divided into three types of copper pipes: A, B and C. The type a pipe is thick wall type, which is suitable for higher use; B-TUBE is suitable for general use; C-tube is thin-walled copper tube, which is basically equivalent to en1057-x. The outer diameter deviation can be divided into ordinary grade and higher precision grade, but they are all lower than foreign standards. At present, only a few small diameter copper tubes produced by domestic manufacturers can meet the requirements of the new standard. Other technical indexes of the new national standard are basically the same as those of foreign standards, but at present, no domestic manufacturer can strictly implement this standard to produce copper water pipes.