Advanced American valve quality certification standard system

With consideration to rapid development of pipelines in China and active promotion of domestic production of valves, this paper reviews present situations of valve design and manufacturing in China. It is pointed out that root cause of internal leakage of valves is the absence of specific certification standards for quality of valves. Without these standards, it is not possible to guarantee quality of valves produced. American valve quality certification standard system is characterized by strict control over qualification of the secondary valve suppliers, designation of third-party valve quality certification institutes, tighter visual inspection of valves and performance tests for materials deployed for fabrication of valves, tests for closing performances of valves, tests for connection strength of valve rods and closing elements, tests for functions of valve hand wheels and other specific tests. The system also clarifies minimum standards for valves and relevant elements. Finally, proposals are proposed to establish quality standard system to cover fabrication, materials, inspections, tests and maintenance of valves.