The atmospheric-pressure gas pipeline that is directly connected to the LNG cryogenic tank is not considered a pressure pipeline; so where should it be classified?

The pipeline behind the safety valve, generally industrial process pipelines

It is either the pipeline behind the safety valve, or the gas-phase pipeline directly connected to the cryogenic, atmospheric-pressure LNG sphere tank. @sycee

Is the term \"low-temperature, normal-pressure spherical tank\" correct? Also, when you mention the gas-phase pipeline, are you referring to BOG or the vapor returned to the tank?

The pipeline from the tank to the compressor, which of course includes the BOG vapor; this vapor is compressed and sent outside or condensed back into the storage tank.

Here, it mainly refers to low-temperature gas pipelines at normal pressure with an operating pressure of several thousand pascals and a temperature of -162°C.

The pipes for BOG are definitely not pressure pipes; they are not subject to regulation and are under the responsibility of the entity that uses them for supervision. Regarding regulatory measures, first of all, even for pressure pipelines, the entities that use such containers should have their own management procedures in place. One cannot rely entirely on regulatory and special inspection agencies. Equipment such as simple pressure vessels and electric hoists has also seen its regulation relaxed, with management taken over by the companies themselves; then why can’t the BOG pipelines do the same?

I checked this specifically for you – the statement that “it does not fall under the category of pressure pipelines” is incorrect. According to Article 99(3) of Chapter 8 of the Regulations on the Safety Supervision of Special Equipment, issued in 2009, a pressure pipeline refers to a tubular device that uses pressure to transport gases or liquids. It is defined as a pipeline whose maximum operating pressure is greater than or equal to 0.1 MPa (gauge pressure), and which transports gas, liquefied gas, steam, or liquid media that are flammable, explosive, toxic, corrosive, or have a maximum operating temperature greater than or equal to their standard boiling point; such pipelines also must have a nominal diameter of more than 25 mm. ------------Due to the flammable and explosive substances inside, it can be classified as a pressure pipeline. That needs to be regulated.

This post was last edited by zyc8445 on 2018-5-25 22:15. I. Pipes with a diameter of at least DN50 and a working pressure of at least 0.1 MPa are considered pressure pipes. II. If it is not a pressure pipeline, mandatory supervision is not required, but the requirements for taking photographs as specified in the design documents, as well as the pressure tests and airtightness tests, remain the same; this is determined by the properties of the material. The owner themselves must be responsible for checking this; it is a matter of taking responsibility for oneself. What you’re referring to is probably a vent pipe; in fact, some low-temperature pipes with a DN40 diameter don’t require supervision or inspection. If you’re still concerned, you can ask the design team to classify it as a pressure pipe.

Internal pipelines in enterprises are industrial process pipelines; it is sufficient for them to meet the design technical requirements. If they fall under the category of pressure pipelines, then supervision by relevant authorities is also required. Pressure pipelines represent those with higher risks, and therefore must be subject to **mandatory supervision**

Unregulated pipelines. The maximum operating pressure did not exceed 0.1 Mpag