Classification of pressure pipelines: GA/GB/GC

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What is a pressure pipeline? Pressure pipelines refer to tubular devices that utilize a certain pressure to transport gases or liquids. Conditions that pressure pipelines must meet: (1) Pressure range: The maximum operating pressure shall be greater than or equal to 0.1 MPa (gauge pressure). (2) Transport medium: gases, liquefied gases, steam, flammable, explosive, toxic, corrosive substances, as well as liquids with a maximum operating temperature equal to or higher than their standard boiling point. (3) Pipe specification: Pipes with a nominal diameter of 50 mm or greater. Note: This does not apply to pipelines with a nominal diameter of less than 150 mm and a maximum operating pressure of less than 1.6 MPa (gauge pressure), as well as to the pipelines that form part of the equipment used for transporting non-toxic, non-flammable, and non-corrosive gases. Based on their purpose and the pressures they are designed to withstand, pressure pipelines are mainly classified into: long-distance pipelines (GA category), utility pipelines (GB category), and industrial pipelines (GC category). A brief introduction to each of these is provided below. I. Transmission Pipelines (GA Category) Definition: Transmission pipelines refer to pipelines used for transporting oil and gas products between production sites, storage facilities, and user stations; they are classified into GA1 level and GA2 level. (1) GA1 class long-distance pipelines: —— Long-distance pipelines that transport toxic, flammable, or explosive gas media, with a maximum operating pressure greater than 4.0 MPa ； —— Long-distance pipelines for transporting toxic, flammable, or explosive liquid media, with a maximum operating pressure of 6.4 MPa or higher and a transmission distance of 200 km or more ； (2) GA2-class long-distance pipelines: Suitable for other long-distance pipelines other than those of GA1 class. Main characteristics of long-distance pipelines: (1) Long-distance transportation: They are typically used for transporting goods over long distances, enabling the delivery of the medium produced in one location to storage facilities or end-users. (2) High-volume transportation: Typically, it features larger pipe diameters, allowing the transport of large quantities of the medium being carried. (3) High-pressure transmission: The maximum operating pressure of GA1-class long-distance pipelines can reach over 6.4 MPa, and the maximum operating pressure of GA2-class long-distance pipelines is also high. (4) High safety requirements: Since toxic, flammable, and explosive materials are usually transported, extremely high safety standards are required, necessitating strict safety measures. II. Utility Piping (GB Class) Definition: Utility piping refers to gas pipelines and heat pipelines used for public services or domestic purposes within cities or towns. Gas pipelines are classified as GB1 grade, while heat pipelines (for heating and steam) are classified as GB2 grade. Main characteristics of utility pipelines: (1) Universality and wide distribution – Utility pipelines are widely present in various living and industrial environments such as cities and industrial parks, covering a very broad range of areas. (2) Public utility pipelines that are closely related to people’s livelihoods have a direct impact on the quality of residents’ lives and the stability of industrial production; pipelines for water supply, gas, and heating, among others, affect people’s basic living needs. (3) High safety standards: Since public interests are at stake, utility pipelines must adhere to high-standard safety regulations during design, construction, and operation. (4) Long-term stability requirements: Utility pipelines are typically systems that operate over long periods of time, and their long-term stability and durability must be taken into account during design. III. Industrial pipelines (GC category) Definition: Industrial pipelines refer to pipes used in industrial production processes to transport gases, liquids, steam, chemicals, raw materials, waste gases, or other substances. They are classified into three grades: GC1, GC2, and GCD. (1) GC1-class industrial pipelines: Industrial pipelines that meet either of the following conditions are classified as GC1 class: (1) Those that transport media with an extremely hazardous toxicity level as specified in the \"Catalogue of Hazardous Chemicals (2015 edition)\". (2) For transporting flammable gases of Class A or B, or flammable liquids of Class A as specified in GB 50160 and GB 50016, with a design pressure of P ≥ 4.0 MPa. (3) For transporting flammable fluid media or toxic fluid media, with a design pressure of P ≥ 4.0 MPa and a design temperature of ≥ 400°C. (4) For transporting fluid media with a design pressure of P ≥ 10 MPa. (2) GC2 class industrial pipelines: Industrial pipelines that meet either of the following conditions are classified as GC2 class: (1) Those that transport flammable gases of categories A or B, or flammable liquids of category A, as specified in GB 50160 and GB 50016, with a design pressure P