Do the feed pipes of steam boilers belong to pressure pipelines?
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For example: 1. Design pressure of 2.5 MPa, operating temperature of 150°C, medium is unsaturated water (deionized water), pipe diameter DN40; 2. Design pressure of 2.5 MPa, operating temperature of 150°C, medium is unsaturated water (deionized water), pipe diameter DN50; 3. Design pressure of 2.5 MPa, operating temperature of 150°C, medium is unsaturated water (deionized water), pipe diameter DN65. Are the above three pipes considered pressure pipes since their nominal diameter is ≥50? Isn’t the first one a pressure pipeline? Are the last two pressure pipelines? Some people say that liquid water pipelines are not pressure pipelines under any circumstances, on the grounds that a temperature above the boiling point implies toxicity or flammability, properties that water does not possess ； Additionally, some people say that according to the latest standards, as long as the temperature is above the boiling point and the nominal diameter is ≥50 mm, such pipelines still fall under the category of pressure pipelines, even if the medium is not a toxic or flammable liquid ； Please share your opinions.
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; furthermore, such pipelines 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. So it belongs to pressure pipelines
Agree with the view above; it belongs to pressure pipelines
Flammable, explosive, toxic, corrosive, liquids with a maximum operating temperature equal to or higher than their standard boiling point… These five criteria are listed side by side; meeting any one of them is sufficient. According to the definition on the second floor, DN40 pipes are excluded as their diameter does not meet the requirements; the other two diameters are considered pressure pipes.
The first one is not; the latter two are both pressure pipelines
The original poster is correct; the first one is not a pressure pipeline, while the latter two are pressure pipelines.
According to the latest definition of pressure pipelines, the last two should be considered pressure pipelines, while the first one is not, as it is DN40 in size.
It seems my course materials need to be revised; they must keep up with the times!
The boiler feedwater pipeline refers to the section from the feedwater pump to the boiler; it is part of the boiler and is not classified as a pressure pipeline!
This post was last edited by yujwlhh on 2020-10-22 08:09. I agree with the view above: the boiler feed pipes are mostly considered to be power pipes, GCD pipes, and not pressure pipes. If the pipeline meeting the above conditions is located in a pipe tray, then it certainly belongs to a pressure pipeline.