| minal Size | Carbon / Stainless Steel Pipe OD (mm) | BS 1387:1985 OD (mm) | Cu-Ni Pipe - OD (mm) | ASTM B88M copper tube | ||||||||
| DN/OD | Inch (in) | ISO | DIN | BSP | JIS/KS | USA ASTM | Light | Medium/ Heavy | Metric | USA Inch size | Metric OD (mm) | |
| 6 | ||||||||||||
| 8 | ||||||||||||
| 6* | 1/8 | 10.2 | 10.2 | 10.2 | 10.5 | 10.3 | 10 | |||||
| 8* | 1/4 | 13.5 | 13.5 | 13.5 | 13.8 | 13.7 | 13.6 | 13.9 | 12 | |||
| 15 | ||||||||||||
| 10 | 3/8 | 17.2 | 17.2 | 17.2 | 17.3 | 17.1 | 17.1 | 17.4 | 18 | |||
| 15 | 1/2 | 21.3 | 21.3 | 21.3 | 21.7 | 21.3 | 21.4 | 21.7 | 22 | |||
| 20 | 3/4 | 26.9 | 26.9 | 26.9 | 27.2 | 26.7 | 26.9 | 27.2 | 28 | |||
| 25 | 1 | 33.7 | 33.7 | 33.7 | 34 | 33.4 | 33.8 | 34.2 | 30 | 28.24 | 35 | |
| 32 | 1 1/4 | 42.4 | 42.4 | 42.4 | 42.7 | 42.2 | 42.5 | 42.9 | 38 | 34.59 | 42 | |
| 40 | 1 1/2 | 48.3 | 48.3 | 48.3 | 48.6 | 48.3 | 48.4 | 48.8 | 44.5 | 40.94 | ||
| 50 | 2 | 60.3 | 60.3 | 60.3 | 60.5 | 60.3 | 60.2 | 60.8 | 57 | 54.05 | 54 | |
| 65 | 2 1/2 | 76.1 | 76.1 | 76.1 | 76.3 | 73 | 76 | 76.6 | 76.1 | 66.75 | 67 | |
| 80 | 3 | 88.9 | 88.9 | 88.9 | 89.1 | 88.9 | 88.7 | 89.5 | 88.9 | 79.85 | 79 | |
| 90 | 3 1/2 | 101.6 | 101.6 | 101.6 | 101.6 | 101.6 | ||||||
| 100 | 4 | 114.3 | 114.3 | 114.3 | 114.3 | 114.3 | 113.9 | 114.9 | 108 | 106.27 | 105 | |
| 125 | 5 | 139.7 | 139.7 | 139.7 | 139.8 | 141.3 | 140.6 | 133 | 131.67 | 130 | ||
| 150 | 6 | 168.3 | 168.3 | 165.1** | 165.2 | 168.3 | 166.1 | 159 | 157.68 | 156 | ||
| 200 | 8 | 219.1 | 219.1 | 219.1 | 216.3 | 219.1 | 219 | 208.48 | 206 | |||
| 250 | 10 | 273 | 273 | 273 | 267.4 | 273 | 267 | 260.5 | 257 | |||
| 300 | 12 | 323.9 | 323.9 | 323.9 | 318.5 | 323.8 | 323.8 | 312.11 | 308 | |||
| 350 | 14 | 355.6 | 355.6 | 355.6 | 355.6 | 355.6 | 368 | 363.72 | ||||
| 400 | 16 | 406.4 | 406.4 | 406.4 | 406.4 | 406.4 | 419 | 414.52 | ||||
| 450 | 18 | 457 | 457 | 457 | 457 | 457.2 | 457.2 | 465.32 | ||||
| 500 | 20 | 508 | 508 | 508 | 508 | 508 | 508 | 516.94 | ||||
| JIS = Japanese Industrial Standard | KS = Korean standard |
| **Depending upon the standard number, this may also be 168.3 mm | *Not in ISO 6708 |
|
ISO 6708
1. DN: An alphanumeric designation of size for components of a pipework system, which is used for reference purposes. It comprises the letters DN followed by a dimensionless whole number which is indirectly related to the physical size, in millimetres, of the bore or outside diameter of the end connections. |
2. The number following the letters DN does not represent a measurable value and should not be used for calculation purposes except where specified in the relevant standard.
3. In those standards which use the DN designation system, any relationship between DN and component dimensions should be given, e.g. DN/OD or DN/ID. |
US 7397 
BR 2769 
CA 1711 
AU 1616 
TH 1537 
JP 1449 
SG 1156 
MY 651 
