Why add gb ahead of the valve such as the standard, standard?

Is the meaning of American standard, American standard valve is usually called American standard ball valve, American standard what gate valves and other valves are created according to the American standard valve which category. The standard manual is a very important document. It illustrates the compilation process, standard specifications and analytical information such as the main technical problems. Although the standard manual is a file used in the process of standard declaration. But take a look at the standard specification, the understanding of the standard and need to be aware of problems in the execution is very helpful. Standard manual is really has a great role on the comprehensive understanding of the standard, and a series of evolution, there is a process of continuous record. Understand the other it is good to understand the American standard valve, gb valve is the valve standard in our country, the German standard valves is Germany standard, Japanese valve is Japanese standard, other and so on. Is the meaning of American standard, American standard valve is usually called American standard ball valve, American standard what gate valves and other valves are created according to the American standard valve which category. The standard manual is a very important document. It illustrates the compilation process, standard specifications and analytical information such as the main technical problems. Although the standard manual is a file used in the process of standard declaration. But take a look at the standard specification, the understanding of the standard and need to be aware of problems in the execution is very helpful. Standard manual is really has a great role on the comprehensive understanding of the standard, and a series of evolution, there is a process of continuous record. Understand the other it is good to understand the American standard valve, gb valve is the valve standard in our country, the German standard valves is Germany standard, Japanese valve is Japanese standard, other and so on.