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Piping Dimensions (DN Vs NPS)

The size of pipes, fittings, flanges and valves are given in two Units

NPS = Nominal Pipe Size (Inches)

DN = Diameter Nominal (Metric)


Following is the comparison :

Diameter Nominal
DN
(mm)
Nominal Pipe Size
NPS
(inches)
6
1/8
8
1/4
10
3/8
15
1/2
20
3/4
25
1
32
1 1/4
40
1 1/2
50
2
65
2 1/2
80
3
100
4
150
6
200
8
250
10
300
12
350
14
400
16
450
18
500
20
550
22
600
24
650
26
700
28
750
30
800
32
900
36
1000
40
1050
42
1100
44
1200
48
1300
52
1400
56
1500
60
1600
64
1700
68
1800
72
1900
76
2000
80
2200
88
2400
96
2600
104
2800
112
3000
120
3200
128
  

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