I didn’t understand the definition of pressure pipelines; I’ll ask again.

Pipes that can withstand pressure are all called pressure pipes; it’s just that their pressure resistance levels vary depending on the wall thickness

**General Administration of Quality Supervision, Inspection and Quarantine – “Announcement by the General Administration of Quality Supervision, Inspection and Quarantine on the Revision of the ‘Catalogue of Special Equipment’ (No. 114, 2014)”

Thank you for the reply! It’s just that the interpretation of the definitions in the standards is a bit overly meticulous. I’m not sure whether the condition is ‘or’ or ‘and’ – the maximum temperature of the medium does not reach the boiling point

How are corrosion and toxicity defined?

The definition of pressure pipelines itself is not clear enough; it’s only natural to read it carefully, not understand it, and ask for help humbly – why be so harsh? If the General Administration for Quality Supervision and Inspection does not provide an interpretation, I ask you: according to the Catalogue of Special Equipment, are DN100 steam pipes that are non-toxic, non-flammable, and non-corrosive considered pressure pipes or not? I’ve seen your statements before; claiming that a pipe is considered a pressure pipe just because it has a pressure gauge and readings is nonsense. For a fluid to flow, there needs to be a pressure difference – otherwise how can it flow? That would mean every pipe is a pressure pipe.

During our training on pressure pipelines, the instructor emphasized this issue regarding the definition, and asked us to see if we could understand it: Each part of the definition of pressure pipelines should be understood separately. 1. The maximum operating pressure is greater than or equal to 0.1 MPa (gauge pressure); this is easy to understand, and there shouldn’t be any problems with it； 2. The medium is a gas, liquefied gas, vapor, or a liquid that is flammable, explosive, toxic, corrosive, and has a maximum operating temperature equal to or higher than its standard boiling point ； In this case, the relationships between them are all of the type “or”; if it were a “and” relationship, then pressure pipelines would basically not exist ； 3. Pipes with a nominal diameter of 50 mm or more; this condition is interdependent with the previous two – that is, both pressure and the type of material must meet certain requirements, as well as the pipe diameter, for it to be classified as a pressure pipe. Finally, this does not apply to pipes and the pipe systems of 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). ”Regarding this point, special attention should be paid to the issue of steam. Agencies in various regions have written to the General Administration for Quality Supervision, Inspection and Quarantine to seek clarification, and the administration issued a document on this matter; I can’t remember exactly what it said, but it clearly states that steam pipes are not included in the exceptions. Based on the above explanations, given that this pipeline has a specified pressure and diameter range, and the medium involved is corrosive, it should be classified as a pressure pipeline and is subject to the regulations set out in the \"Safety Technical Supervision Regulations for Pressure Pipelines\".

Sir, what I’m saying is that there’s a problem with your reading comprehension skills; therefore, I suggest you go back to school and review them. The day of successful graduation is the day when this definition is understood.

Thank you for the reply! I am currently learning about the criteria for determining whether a medium is toxic or corrosive!