Questions regarding the definition of pressure pipelines

Pipes with a nominal diameter of less than 150 mm are not considered pressure pipes

Article 4 These provisions do not apply to the following pipelines: (3) Pipelines that transport non-toxic, non-flammable, and non-corrosive gases, with a nominal diameter of less than 150 mm and a maximum operating pressure of less than 1.6 Mpa. According to this regulation, whether it qualifies as a pressure pipeline should be related to the pipe diameter, right?

Pressure pipelines that are not subject to the regulations on the safety management and supervision of pressure pipelines

This post was last edited by Liu Jiajia on 2018-12-28 at 10:42. 1. The definition of pressure pipelines can be divided into narrow and broad senses; in the narrow sense, pressure pipelines refer only to those that are subject to regulation, while in the broad sense, it is a concept used in the field of engineering design, including those pressure pipelines that are not subject to regulation but fall within the scope of engineering design standards. Pressure pipelines as defined in standards such as GB/T 20801 and GB 50316. 2. Article 2 of the Law of the People’s Republic of China on the Safety of Special Equipment stipulates that \"**special equipment shall be subject to catalog management.\" The catalog of special equipment is formulated by the department under the State Council responsible for the safety supervision and management of special equipment, and shall come into effect after approval by the State Council. ”Therefore, to determine whether it constitutes a pressure pipeline subject to regulation, the \"Catalogue of Special Equipment\" shall be taken as the standard. Within the directory scope, it takes control; outside the directory scope, it does not. 3. The “Catalogue of Special Equipment” defines pressure pipelines as follows: “Pressure pipelines refer to tubular devices that use a certain pressure to transport gases or liquids. They are defined as those with a maximum operating pressure of 0.1 MPa (gauge pressure) or more, where the medium is a gas, liquefied gas, steam, or a liquid that is flammable, explosive, toxic, corrosive, and has a maximum operating temperature equal to or higher than its 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. ” There are three points to note in this definition: 1) In the first half, all values are greater than or equal to, that is, the maximum operating pressure is greater than or equal to 0.1 MPa (gauge pressure), and the nominal diameter is greater than or equal to 50 mm. The latter part consists of those with values that are less than a certain threshold: the maximum operating pressure is less than 1.6 MPa (gauge pressure), and the nominal diameter is less than 150 mm. 2) Steam is not included in the definition for the latter part; that is, steam pipelines are considered pressure pipelines as long as their maximum operating pressure is greater than or equal to 0.1 MPa (gauge pressure) and their nominal diameter is greater than or equal to 50 mm. 3) QA Office Special Document [2015] No. 675 (issued on June 19, 2015) provides further clarification regarding the definition of pressure pipelines in the “Catalogue of Special Equipment.” It specifies that pipelines for transporting non-toxic, non-flammable, and non-corrosive gases, with a nominal diameter of less than 150 mm and a maximum working pressure of 1.6 MPa (gauge pressure), do not include liquefied gases, steam, and oxygen among such non-toxic, non-flammable, and non-corrosive gases. 4. The poster only provided the air pipeline pressure (0.8 MPa), but not the pipe diameter. According to the definition of \"pipes for transporting non-toxic, non-flammable, and non-corrosive gases with a nominal diameter of less than 150 mm and a maximum operating pressure of less than 1.6 MPa (gauge pressure)\\", if the nominal diameter is 150 mm or greater, it is considered a pressure pipe; otherwise, it is not. It depends on the pipe diameter.

It is clearly stated in the regulations you sent: Pipes used for transporting non-toxic, non-flammable, and non-corrosive gases, with a nominal diameter of less than 150 mm and a maximum operating pressure of less than 1.6 Mpa, are not considered pressure pipes. The 0.8MPa air pipeline meets both of the above conditions simultaneously.

1. The Provisions on the Safety Management and Supervision of Pressure Pipelines have been repealed； If the pipe diameter is 150 mm or greater, it falls under the scope of supervision, and a use registration certificate is required