Are circulating water pipes larger than DN150 considered pressure pipes?
Thread Content
This post was last edited by vrain on 2016-12-12 at 10:15. Based on: **Announcement by the General Administration of Quality Supervision, Inspection and Quarantine regarding the revision of the “Catalogue of Special Equipment”. 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, carrying gases, liquefied gases, steam, or liquids that are flammable, explosive, toxic, corrosive, and have a maximum operating temperature equal to or higher than their standard boiling point, and with 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. . The pressure is currently higher than that in the circulating water pipes with a diameter of DN150, at 4 barg. What do you all think? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Reply: This shouldn’t be it. Thank you all for your discussions. Firstly, for pressures greater than 150, it must be a pipeline for non-toxic, non-flammable, and non-corrosive gases; therefore, it does not fall under this category. Thank you all for your discussions
According to the criteria you listed, those with DN150 are all greater than 150 mm, so they don’t fall within this range
Circulating water pipes are by no means pressure pipes.
It does not belong. The key to understanding the definition above lies in its modifiers and sentence structure. A detailed breakdown is as follows: 1) Pipes whose maximum operating pressure is greater than or equal to 0.1 MPa (gauge pressure), and which transport gases, liquefied gases, or steam, with a nominal diameter of 50 mm or more, are considered pressure pipes (with the exception of pipes and equipment used for transporting non-toxic, non-flammable, and non-corrosive gases, where the nominal diameter is less than 150 mm and the maximum operating pressure is less than 1.6 MPa (gauge pressure)) ； 2) Pipelines with a maximum operating pressure of 0.1 MPa (gauge pressure) or higher, that transport flammable, explosive, toxic, corrosive liquids, or liquids whose maximum operating temperature is equal to or higher than their standard boiling point, and whose nominal diameter is 50 mm or greater, are considered pressure pipelines (except for the pipelines that are part of the equipment itself) ； It can be seen that circulating water pipelines are excluded because the medium they transport is non-flammable, non-explosive, non-toxic, non-corrosive, and its maximum operating temperature does not exceed its standard boiling point (the return temperature of circulating water is generally no higher than 42°C, with a design temperature of around 60°C). Therefore, even if the pressure in the circulating water pipes is high and their diameter is large, they cannot be classified as pressure pipes. This problem is proven.
It is not a pressure pipeline; for media that are non-toxic, non-flammable, and non-corrosive with a DN > 150, it is only gases that qualify as pressure pipelines. Circulating water systems definitely cannot be considered pressure pipelines.
Not counted. The media for pressure pipelines is restricted. (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.) ) is a special case proposed for gas media
The maximum operating temperature of circulating water is below the boiling point of water, so it is not considered a pressure pipeline