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For micro-internal pressure or low-pressure vessels, the wall thickness obtained by calculating using the internal pressure diameter formula, taking into account corrosion allowance and negative deviations and then rounding off, is generally relatively thin. If this thickness is directly used as the nominal thickness, it will lead to a series of problems related to manufacturing, transportation, and installation. Specifically, these include: a. During the manufacturing of thin-walled cylinders, numerous auxiliary measures are required to ensure roundness and stiffness, which consumes significant human and material resources. For example, internal reinforcement fixtures must be used to round out the tube sections, especially at the joint edges of the two tube sections. b. For thin-walled cylindrical shells, especially when the diameter of the cylinder is relatively small, the welding method of single-side welding with double-side formation is commonly used. However, single-sided welding of thin-walled containers is prone to defects such as lack of penetration, burn-through, and poor backside formation. Even with backing plates added, it is difficult for the plates to adhere tightly, resulting in welding defects at the root. At the same time, the edge misalignment and angular deformation that occur during the alignment of container cylinders have a much greater impact on the welding quality of thin-walled cylinders than that of thick-walled cylinders. c. Due to the poor stiffness of thin-walled containers, which makes them prone to deformation, temporary support or reinforcement is usually required for the cylinder during transportation and lifting. If the costs of manufacturing, transportation, and installation are too high, it is better to increase the thickness of the cylinder, which also helps to ensure quality. Therefore, standards such as GB 150 (past versions) also specify the minimum thickness of pressure vessel cylinders. GB 150-1989 sets strict requirements for the minimum wall thickness of cylinders in carbon steel and low-alloy steel pressure vessels. The requirement in GB 150-98 for the minimum wall thickness of carbon steel and low-alloy steel is: for DN 1200 mm, δmin = 0.001D + 4 mm. GB 150-1989 takes into account in a relatively comprehensive manner the minimum wall thickness requirements for pressure vessels made of carbon steel and low-alloy steel regarding transportation, manufacturing, and lifting. The requirements for the minimum wall thickness of carbon steel specified in GB 150-1998 and GB/T 150-2011, as well as those for high-alloy steel in each version, are primarily based on welding considerations; as for other aspects such as transportation and installation, the designer must take the actual conditions into account. Overall, GB 150-1989 is quite practical and is likely to be favored by designers; however, its highly detailed and strict regulations can hinder technological progress. However, later versions of GB 150 only provide general provisions regarding the forces to be considered during transportation or lifting; in the context of current design and manufacturing practices in China, this makes it difficult to apply in practice. Of course, there are also successful examples, such as the lifting of the large tower; the lifting plan (including the required reinforcement measures) was proposed by the lifting company and approved by the design team. For some things, **standards and industry standards should not be specified in too much detail, but corporate standards and organization standards can be. For example, a wealthy and cautious owner established the following requirement for the minimum thickness of the equipment: DN900, tmin=11 ； The aforementioned thickness includes a 3mm corrosion margin. Of course, the owner also stipulated that this minimum thickness can be negotiated if quality can be guaranteed.