I am completely confused. Are pipelines containing Class C flammable liquids classified as pressure pipelines in the special equipment catalog?
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This post was last edited by Rappy on 2019-4-15 16:15. I read many related posts, but none of them gave a clear answer. I was completely confused. . . At present, there are only a few standards related to pressure pipelines.: "Special Equipment Catalog"-2014 ； "Pressure Piping Specification-Industrial Piping" GB/T20801-2006 ； "Pressure Pipeline Safety Technical Supervision Regulations - Industrial Pipelines" TSG D0001-2009. The definition of pressure pipelines in the "Special Equipment Catalog" is: (1) The maximum working pressure is greater than or equal to 0.1MPa (gauge pressure) ； (2) The medium is gas, liquefied gas, steam or a liquid that is flammable, explosive, toxic, corrosive and has a maximum working temperature higher than or equal to the standard boiling point ； (3) The nominal diameter is greater than or equal to 50mm. If all three conditions are met, it is a pressure pipeline. Except for pipes with a nominal diameter less than 150mm and a maximum working pressure less than 1.6MPa (gauge pressure) that transport non-toxic, non-flammable, non-corrosive gases and pipes belonging to the equipment body. The definitions of pressure pipelines in "Pressure Pipeline Specifications - Industrial Pipelines" and "Pressure Pipeline Safety Technical Supervision Regulations - Industrial Pipelines" are the same: (1) The maximum working pressure is greater than or equal to 0.1MPa (gauge pressure) ； (2) The medium is gas, liquefied gas, steam or a liquid that is flammable, explosive, toxic, corrosive and has a maximum working temperature higher than or equal to the standard boiling point ； (3) The nominal diameter is greater than 25mm. If all three conditions are met, it is a pressure pipeline. Among them, Article 1 is not controversial ； The new version of the "Special Equipment Catalog" raises the starting point for pressure pipeline diameters, and Article 3 is not controversial. The crux of the matter lies in Article 2: The "Special Equipment Catalog" only writes the word "flammable" for liquids, and does not provide a more detailed definition of "flammable" ； The "Pressure Pipeline Specifications - Industrial Pipelines" 3.11 Flammable and Explosive Media and the "Pressure Pipeline Safety Technical Supervision Regulations - Industrial Pipelines" Annex A have specific definitions of "flammable liquids", which are also the same.: Class A and B flammable liquids defined in "Code for Fire Protection Design of Petrochemical Enterprises" GB50160 and "Code for Fire Protection Design of Buildings" GB50016, and Class C flammable liquids whose working temperature exceeds their flash point. So, for example: Does a pipeline with a maximum working pressure of 16MPa, a pipe diameter of DN80, and a non-toxic, non-corrosive Class C flammable liquid whose working temperature is lower than its flash point belong to the pressure pipelines defined in these three standards? In other words, is the scope of Article 2 "flammable liquids" in these three standards the same? Analysis on the definition of "flammable liquid" according to "Pressure Pipeline Specifications - Industrial Pipelines" and "Pressure Pipeline Safety Technical Supervision Regulations - Industrial Pipelines": This kind of medium is not even considered a flammable liquid and does not comply with Article 2, so it does not belong to a pressure pipeline. There was a project recently, and the design institute thought so, and it was not within the scope of safety supervision. . .
The classification of toxicity, corrosiveness and fire risk of media in pressure pipelines should be based on the "Chemical Safety Data Sheet" of the medium and determined in accordance with the principles of Annex A of the Pressure Pipeline Safety Technical Supervision Regulations - Industrial Pipelines (TSG D0001-2009).
Appendix A is shown in the picture. Does that mean that this pipeline is not a pressure pipeline and does not need to be inspected as special equipment?
This is the original* * Response from the General Administration of Quality Supervision, Inspection and Quarantine
It is mentioned in the main post, but it has nothing to do with pressure or pipe diameter. The three standards are (1) (2) (3) to be considered a pressure pipe if they are met at the same time. Class C liquids with operating temperatures below the flash point are not considered flammable liquids, and (2) are not met.
GB/T20801.1 Chapter 3.14 The definition of flammable media has been clearly written.: Fire hazard regulations are the general name for Class A, B, C and fluids with operating temperatures above the flash point~~
Here's: Class C flammable liquids whose working temperature exceeds their flash point should be regarded as Class B flammable liquids~~ It is very clear~ It just means that this part of Class C liquids is regarded as Class B liquids. It didn’t say that Class C flammable liquids with operating temperatures lower than their flash points are not considered flammable liquids.~~
Therefore, Class C liquids above DN50 and whose pressure meets the requirements are certainly considered pressure pipes.
Your GB/T20801 is the first draft, not the official version. The official version is as shown above. The definition of this term is a very clear scope definition. As far as 3.11 is concerned, Class C liquids with operating temperatures below the flash point are obviously not considered flammable or explosive media. Moreover, the first draft clearly stated Class C, but the official version removed Class C, which also shows that the official version no longer considers Class C to be a flammable medium.