Standard Pipe Diameters and DN Equivalents in Steel Pipes

Pipe Diameters and DN Equivalents in Steel Pipes

DN (Nominal Diameter): A term used in European standards that indicates the nominal inner diameter of the pipe in millimeters.

Standard Pipe Diameters: Steel pipes are produced in various diameters. The most commonly used standard pipe diameters and their DN equivalents are shown in the table below:

Outside Diameter (mm)	DN	Wall Thickness (mm)
10.2	6	1.0
13.3	8	1.2
17.2	10	1.2
21.3	12	1.5
26.9	15	1.7
33.7	20	2.0
42.4	25	2.3
48.3	32	2.9
60.3	40	3.2
73.0	50	3.6
88.9	65	4.0
108.0	80	5.0
133.0	100	6.0
168.3	125	7.1
219.1	150	8.0

Note: This table shows the most commonly used pipe diameters and DN equivalents. For more information, you can refer to the catalogs of pipe manufacturers or relevant standards.

Calculating DN Equivalent: The DN equivalent can be calculated using the following formula:

DN = (Outside Diameter - Wall Thickness) x 10

Example: A pipe with an outside diameter of 42.4 mm and a wall thickness of 2.3 mm has a DN equivalent of:

DN = (42.4 - 2.3) x 10 = 400

The DN equivalent of this pipe is 40.

Selecting Steel Pipes: There are many factors to consider when selecting steel pipes. Some of these are:

Application: What will the pipe be used for? (Water, gas, oil etc.)
Pressure: What is the pressure of the fluid that will flow through the pipe?
Temperature: What is the temperature of the fluid that will flow through the pipe?
Durability: How durable should the pipe be?
Cost: What is the cost of the pipe?

Standard Pipe Diameters and DN Equivalents in Steel Pipes

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