Standard Pipe Diameters and DN Equivalents in Steel Pipes

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?
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