The main reasons are as follows:
(1) The pipeline itself has defects and has not passed the pressure test;
(2) The gasket joint at the flange connection is not handled properly;
(3) Flange bolts are not tightened in a reasonable way.
The defective pipes should be repaired or even replaced. If the center of the butt joint pipe deviates too much, it should be removed and rearranged. After alignment, the connecting bolts should be in the basically free position
After all pipelines are installed, the pressure strength and leakage test of the system should be carried out. It must be replaced with a new one.