Can the 8163 pipeline be used in any situation other than GC1?

Your understanding still has problems. To give a simple example, consider a GC1 pipe with a diameter of DN100, to which there is a drain pipe with a DN40 diameter. According to your understanding, if GB9948 applies to the DN100 pipe, then GB8163 could be applied to the DN40 pipe – after all, they are both non-pressure pipes. Do you think that’s correct? Let’s clarify one concept first: the choice of steel pipe manufacturing standards has nothing to do with whether it is a pressure pipeline or not. It is selected based on a combination of medium, temperature, and pressure. Under these conditions, GB8163 can be used; if it is applicable, then it can be utilized, otherwise a higher standard should be adopted. If you have time, you can look up the GB9948 and GB8163 standards; the first clause in them clearly states the applicable range of steel pipes, so it’s easy to understand once you read it. GB8163 refers to general seamless steel tubes used for transporting fluids, while GB9948 applies to seamless steel tubes used for furnace tubes, heat exchanger tubes, and pressure pipelines in the petrochemical industry; you can decide for yourself. The classification of pressure pipes is primarily based on risk control; therefore, pipes are divided into three categories: high, medium, and low. Among them, GB8163 belongs to the medium category, while GB9948 and GB5310 belong to the high category. According to risk control principles, pipes with a high level of danger such as GC1 should naturally use high-quality pipes from the high category like GB9948 and GB5310. However, this does not mean that GB8163 is suitable for all applications other than those involving GC1.

The last edit to this post was made by liaifeng on 2020-10-23 at 21:56. As a supplementary note, in our company, GB8163 pipes are used only for water and air pipelines, with a pressure rating of CL150, as a measure of safety

In our company and similar companies in the industry, natural gas pipelines are all 8163 (not GC1)

Is there any standard specification defining what constitutes an ordinary fluid?

In the specifications, fluids and ordinary fluids are different and should not be confused. In SYSY/T 5037-2018, water, air, and heating steam are defined as ordinary fluids. In GB8163, no examples of fluids are given; it should be sufficient to assume that they meet the definition of fluids

Again, the medium, temperature, and pressure need to be considered together; if all these conditions are met, then it can be used. Our company has suffered losses because of this, so the databases are designed to be strict by default; indeed, it can sometimes be too conservative.

Natural gas is primarily composed of methane, and it belongs to the category of flammable gases; therefore, as long as the design pressure is 4.0 MPa or higher, GB8163 cannot be applied

We also need to check the temperature, the medium used, and so on! You can’t just say that! It’s best to have a design institute create a design for you; following that design will ensure no problems! !

Actually, I still want to ask regarding this issue: from the perspective of design standards and regulations, where is it specified that it cannot be used?

The example you gave of a DN100 system with a DN40 drain pipe is not quite appropriate; if DN100 is classified as GC1, then the drain pipe is also considered a pressure pipeline, so it cannot use the 8163 standard.