Regarding the definition of pressure pipelines
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Dear experts: In accordance with the \"Announcement by the General Administration of Quality Supervision, Inspection and Quarantine on the Revision of the ‘Catalogue of Special Equipment’ (No. 114, 2014)\", the definition of pressure pipelines has been revised 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; furthermore, such pipelines must 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. Question: Do seawater pipelines with an operating pressure of 0.39 MPa and a design pressure of 0.6 MPa, an operating temperature of normal temperature and a design temperature of 50°C, and diameters ranging from DN900 to DN2700, fall under the category of pressure pipelines? Urgently needed. Thank you.
Seawater pipelines should not be considered pressure pipelines
Seawater is corrosive, and everything mentioned by the original poster fits the definition of pressure pipelines
Hello； The seawater pipelines I’m referring to do not meet this requirement: liquids with a maximum operating temperature higher than or equal to their standard boiling point ；
So, do the seawater pipelines I’m talking about fall under the category of pressure pipelines?
At 55°C, the corrosion rate of 20 steel in seawater is much less than 6.25 mm/y; it does not constitute a corrosive fluid, and therefore it does not fall under the category of pressure pipes.
Perhaps due to the temperature conditions, it can be considered not to be a pressure pipeline.
Personally, I don’t think so; the medium doesn’t meet the requirements. It sounds a bit like an LNG receiving station project; if that’s the case, the design firm didn’t include it as a pressure pipeline at that time