A pressure vessel is a sealed device designed to contain gases or liquids while withstanding a specific level of internal pressure. To facilitate more effective scientific management and safety supervision, my country's *Safety Supervision Regulations for Pressure Vessels* classifies these vessels into three categories based on their operating pressure, the hazardous nature of the contained medium, and their functional role within the production process.
Furthermore, distinct regulations regarding design, manufacturing processes, and the scope, content, and methodology of inspections have been established for each specific category of pressure vessel. An import safety and quality licensing system has been implemented for pressure vessels; consequently, goods that have not obtained the requisite import safety and quality license certificate are prohibited from entering the country. Classification must now adhere to the latest standard, TSG 21-2016, *Safety Technical Supervision Regulations for Stationary Pressure Vessels*. Under this standard, vessels are first categorized based on the contained medium-specifically into Group 1 or Group 2 media-and are subsequently classified into Categories I, II, or III based on their pressure and volume parameters. The former classification system-referring to "Class I," "Class II," and "Class III" vessels as defined in the older regulations-is no longer applicable.
The State Administration for Market Regulation has launched a pilot program for the integrity management of pressure-bearing special equipment. This initiative involves 21 major chemical enterprises-located across 13 provinces and municipalities, including Tianjin, Liaoning, Shanghai, and Jiangsu-that possess a solid foundation in management practices. Pressure-bearing special equipment-primarily comprising pressure vessels and pressure pipelines-is utilized extensively within the chemical industry, serving as the "heart" and "arteries" of industrial production.
A pressure vessel is, fundamentally, a sealed container capable of withstanding internal pressure. Pressure vessels serve an exceptionally wide range of purposes, occupying a pivotal position and playing a critical role across numerous sectors-including industrial, civil, and defense applications-as well as in various fields of scientific research. Their usage is most prevalent within the chemical and petrochemical industries; indeed, pressure vessels utilized solely within the petrochemical sector account for approximately 50% of the total global inventory of pressure vessels. In the chemical and petrochemical domains, these vessels are primarily employed in process operations-such as heat transfer, mass transfer, and chemical reactions-as well as for the storage and transportation of pressurized gases or liquefied gases. They also find extensive application in other industrial and civil contexts, such as in air compressor systems. Specifically, various types of specialized compressors-as well as the auxiliary equipment associated with refrigeration compressors (including coolers, buffers, oil-water separators, air storage tanks, evaporators, liquid refrigerant receivers, etc.)-are all classified as pressure vessels. As of the end of 2024, the total number of pressure vessels stood at 5.7163 million, with three accidents recorded . Currently, my country possesses a total of over 6.08 million pressure vessels; of these, more than 1.54 million are utilized by 25,000 chemical enterprises.
