What Is DN Meaning?

What Is DN Meaning?

What Is DN Meaning?
In practical applications of steel pipes and pipelines, people often hear the term "DN". What does' DN 'represent? After checking, it was found that DN represents an average inner diameter. 

Why Use The Concept Of Nominal Diameter(DN)?

Pipes of the same size can have different inner and outer diameters depending on the material and thickness. If pipeline specs are just inner or outer diameter, it'll cause confusion. The nominal diameter provides a standard for communication and operation during the design, selection, and construction processes. The value of DN roughly corresponds to the average inner diameter of the pipeline, but it should be noted that this is only an approximate value.
Comparison Table of DN Outer Diameter Sizes for Commonly Used Steel Pipes
Size
DN (nominal diameter)
Inch conversion value (mm)
Commonly known as outer diameter (mm)
4 points
15
21.3
18
6points
20
26.9
25
1 inch
25
33.7
32
1.2 inch
32
42.4
38
1.5 inch
40
48.3
45
2 inch
50
60.3
57
2.5 inch
65
76.1
76
3 inch
80
88.9
89
4 inch
100
114.3
108
5 inch
125
139.7
140
6 inch
150
168.3
159
8 inch
200
219.1
219
10 inch
250
273
273
12 inch
300
323.9
325
14 inch
350
355.6
377
16 inch
400
406.4
426
18 inch
450
457
480
20 inch
500
508
530
24 inch
600
610
630
28 inch
700
711
720
32 inch
800
813
820
36 inch
900
914
920
40 inch
1000
1016
1020