National standards refer to the standards approved and issued by the national standardization authorities, which are of great significance to the national economic and technological development and are unified throughout the country. The national standard is a national unified technical requirement. The administrative department in charge of standardization in the State Council shall make a plan, coordinate the division of labor, organize the formulation (including revision), and unify the examination, approval, numbering and release. Where there are other provisions in the Law on the Formulation of National Standards, those provisions shall prevail. The service life of national standards is generally 5 years. Over the years, national standards will be revised or re-formulated. In addition, with the development of society, the country needs to formulate new standards to meet the needs of people's production and life. Therefore, the standard is dynamic information.