流量計測量中的ANSI （美國國家標準）的標準管徑
| 公稱直徑 | 管道的壁厚系列 | 管道內徑D/in | 管道內徑D/mm |
| DN50(2in) | 40 80 160 | 2.067 1.939 1.689 | 52.50 49.25 42.90 |
| DN80(3in) | 40 80 160 | 3.068 2.900 2.624 | 77.93 73.66 66.70 |
| DN100(4in) | 40 80 120 160 | 4.026 3.826 3.624 3.438 | 102.26 97.18 92.05 87.33 |
| DN150(6in) | 40 80 120 160 | 6.065 5.761 5.501 5.189 | 154.1 146.3 139.7 131.8 |
| DN200(8in) | 20 30 40 60 80 120 | 8.125 8.071 7.981 7.813 7.625 7.189 | 206.4 205.0 202.7 198.5 193.7 182.6 |
| DN250(10in) | 30 40 60 80 | 10.136 10.020 9.750 9.564 | 257.5 254.5 247.7 242.9 |
| DN300(12in) | 30 40 60 80 | 12.090 11.938 11.626 11.376 | 307.1 303.2 295.3 289.0 |
| DN350(14in) | 30 40 60 80 | 13.250 13.124 12.814 12.500 | 336.6 333.4 325.5 317.5 |
| DN400(16in) | 30 40 60 80 | 15.250 15.000 14.688 14.314 | 387.4 381.0 373.1 363.6 |
| DN450(18in) | 20 30 40 60 80 | 17.376 17.124 16.876 16.500 16.126 | 441.4 435.0 428.7 419.1 409.6 |
| DN500(20in) | 20 30 40 60 80 | 19.250 19.000 18.814 18.376 17.938 | 488.9 482.6 477.9 466.8 455.6 |
| DN600(24in) | 20 30 40 60 80 | 23.250 22.876 22.626 22.064 21.564 | 590.6 581.1 574.7 560.4 547.7 |
