At present, there are four main standards for valve production and selection: European standard (DIN), American standard (ANSI), Chinese standard (GB), Japanese standard (JIS)

DIN is the European standard (also called German standard), the full English name is Deutsches Institut fur Normung, and the corresponding nominal pressure is PN, the full English name is Pressure Nominal

For example, PN10/16/25, PN is the nominal or formal pressure, not the actual pressure.

ANSI is the American standard, the full English name is American National Standards Institute, the corresponding pound class (class), the unit is LB, such as ANSI 150LB.

GB is the Chinese standard, the full English name is Chinese Standard, which is basically the same as the European standard.

JIS is the Japanese standard, the full English name is Japanese Industrial Standards, and the corresponding pressure is K, such as JIS5K/10K/15K.

There is no strict correspondence between the pressure standards of various countries, but they can be converted approximately for reference in selection, as shown in the following table: