Diameter
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Is a DN25 pipe the same as a 1’’ pipe?
One is the national standard, and the other is the American standard
It can be considered the same; depending on the pressure rating, the wall thickness and inner diameter will vary slightly.
It depends on the design standards applied; for DN25, it is definitely 33.4 millimeters. For 1\", it could be 33.4 or 25.4 millimeters.
Why is yours 33.7 instead of 33.4?
Are there A series and B series in the specifications?
If the wall thickness is not taken into account, it’s the same……
This post was last edited by lotos1987 on 2019-4-27 at 23:45. First, it depends on which standard you follow: for stainless steel pipes, GB17395 \"Dimensions, Shapes, Weights and Allowable Deviations of Seamless Steel Pipes\", SH3405 \"Dimension Series for Petrochemical Steel Pipes\", or ASME B36.10 – all of these are standards for pipe dimensions, with various definitions. In GB 17395, the sizes are based on GB1047 \"Definitions and Selection of DN (Nominal Size) for Pipe Fittings\", which specifies three size series. Among them, the Series 1 is the plant-use series; the pipe with an outer diameter of 33.7 mm (DN25) is roughly equivalent to the 1\" pipe specified in ASME B36.1 ； The Series 2 is a non-standard series, and pipes with an outer diameter of 25 mm (ф25) are completely different. It should be noted that the dimension directly used in this standard is the outer diameter D, not the nominal diameter DN. SH3405, on the other hand, is in line with the tables in ASME B36.1; the DN25 size is 33.4 mm. It is better to maintain consistency throughout the entire process, from design and procurement to construction, with regard to the standard systems. Although the dimensional discrepancies between different standard systems are very small, if such discrepancies do occur, it becomes very troublesome to describe them in various design, procurement, and construction documents.