Reasons why the chemical engineering handbook does not recommend using DN65 pipe diameter
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There is a statement in Chapter 33 of Part 4 of the Chemical Engineering Handbook stating that DN65 pipe diameters are not used in ordinary installations. What is the reason for this?
The number of flange bolt holes for the old and new DN65 standards differs, which makes it easy to make mistakes
:Lol, that reason is too far-fetched
1 is that there is a significant difference between the US standard and European standard pipes of 32 and 65. 2 is because the US standard aims to reduce specifications for easier management and cost reduction.
The DN65 diameter is not part of the standard series under national, American, or European standards, and pipe manufacturers generally do not produce it. It is described in the piping design reference books
Many of China’s standards are directly adopted from those of the former Soviet Union. Such as flanges, bolts, and gaskets. Even many calculations are of this kind, such as the thermal and hydrodynamic calculations for boilers. To this day, many accessories have adopted international standards, so the norms are also changing little by little. Some of them are not recommended for use in API610. For example, for pipes of the DN65 size, the metric outer diameter is 73 while the imperial outer diameter is 76; purchasing pipes with a diameter of 76 will likely result in an inability to connect them to flanges of the JB/T81 series. (The JB/T81 series flanges are not container flanges; they represent a standard series of diameters used by many pump and valve manufacturers.) In fact, as long as such flanges can be obtained and can be used properly, this requirement can be ignored – after all, it is only a \"recommendation against\" use, not a \"ban\".
It seems that it’s best not to use pipes with a length of 65 or 180 either