Pressure pipeline issues

Thread Content

Definition of pressure pipelines: Pressure pipelines refer to tubular devices that use a certain pressure to transport gases or liquids. They are defined as pipelines with a maximum operating pressure of 0.1 MPa (gauge pressure) or more, whose medium is gas, liquefied gas, steam, or liquids that are flammable, explosive, toxic, corrosive, and have a maximum operating temperature equal to or higher than their standard boiling point; such pipelines also have a nominal diameter of 50 mm or more. Except for pipes 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 the pipes that form part of the equipment used for transporting non-toxic, non-flammable, and non-corrosive gases. Among them, the safety supervision and management of oil and gas pipelines shall also be carried out in accordance with laws and regulations such as the Work Safety Law and the Oil and Gas Pipeline Protection Law. The part in red font can be understood as follows: 1. For liquids whose operating temperature is not higher than their standard boiling point, as long as they are flammable, explosive, toxic, or corrosive – and since it is a liquid – pipes with a nominal diameter of 50 mm or more can also be considered pressure pipes ； 2. Pipes whose maximum operating temperature is higher than or equal to the standard boiling point (regardless of whether they are toxic or not, and regardless of whether they are flammable or not), and whose nominal diameter is greater than or equal to 50 mm. I’m not sure; I wonder if my understanding is correct. Please give me some guidance, experts. This is because, according to the definition of pressure vessels, these are gases and liquefied gases with a maximum operating pressure of 0.1 MPa (gauge pressure) or more, as well as liquids with a maximum operating temperature equal to or higher than their standard boiling point. It is clearly stated that any liquid medium whose maximum temperature is below the standard boiling point is not a pressure vessel. So, I’m a bit unsure about the definition of pressure pipelines.