NPS Nominal Pipe Size ASME B36.10 and ASME B 36.19
Nominal Pipe Size (NPS) is a American standard sizes for pipes used for high or low pressure and temperature. Pipe size is specified with two non-dimensional numbers: a nominal pipe size (Nominal Pipe Size) based on inches, and a schedule (Sched. or Sch.). Nominal Pipe Size is often incorrectly called National Pipe Size, due to confusion with national pipe thread (NPT). The European designation equivalent to Nominal Pipe Size is DN (diamètre nominal/nominal diameter), in which sizes are measured in millimetres.The term NB (nominal bore) is also frequently used interchangeably with Nominal Pipe Size. According to ASME B36.10 and ASME B 36.19.
Nominal Pipe Size 1/8 to Nominal Pipe Size 3½
| Nominal Pipe Size | DN mm | OD inches (mm) | WT inches (mm) | WT inches (mm) | WT inches (mm) | WT inches (mm) | WT inches (mm) | WT inches (mm) | WT inches (mm) | WT inches (mm) |
| — | — | — | SCH 5 | SCH 10 | SCH 30 | SCH 40/STD | SCH 80 | SCH 120 | SCH 160 | XXS |
| ⅛ | 6 | 0.405 in (10.29 mm) | 0.035 in (0.889 mm) | 0.049 in (1.245 mm) | 0.057 in (1.448 mm) | 0.068 in (1.727 mm) | 0.095 in (2.413 mm) | — | — | — |
| ¼ | 8 | 0.540 in (13.72 mm) | 0.049 in (1.245 mm) | 0.065 in (1.651 mm) | 0.073 in (1.854 mm) | 0.088 in (2.235 mm) | 0.119 in (3.023 mm) | — | — | — |
| ⅜ | 10 | 0.675 in (17.15 mm) | 0.049 in (1.245 mm) | 0.065 in (1.651 mm) | 0.073 in (1.854 mm) | 0.091 in (2.311 mm) | 0.126 in (3.200 mm) | — | — | — |
| ½ | 15 | 0.840 in (21.34 mm) | 0.065 in (1.651 mm) | 0.083 in (2.108 mm) | — | 0.109 in (2.769 mm) | 0.147 in (3.734 mm) | — | 4.78mm | 0.294 in (7.47 mm) |
| ¾ | 20 | 1.050 in (26.67 mm) | 0.065 in (1.651 mm) | 0.083 in (2.108 mm) | 2.41mm | 0.113 in (2.870 mm) | 0.154 in (3.912 mm) | — | 5.56mm | 0.308 in (7.823 mm) |
| 1 | 25 | 1.315 in (33.40 mm) | 0.065 in (1.651 mm) | 0.109 in (2.769 mm) | 2.90mm | 0.133 in (3.378 mm) | 0.179 in (4.547 mm) | — | 6.35mm | 0.358 in (9.093 mm) |
| 1¼ | 32 | 1.660 in (42.16 mm) | 0.065 in (1.651 mm) | 0.109 in (2.769 mm) | 0.117 in (2.972 mm) | 0.140 in (3.556 mm) | 0.191 in (4.851 mm) | — | 6.35mm | 0.382 in (9.703 mm) |
| 1½ | 40 | 1.900 in (48.26 mm) | 0.065 in (1.651 mm) | 0.109 in (2.769 mm) | 0.125 in (3.175 mm) | 0.145 in (3.683 mm) | 0.200 in (5.080 mm) | — | 7.14mm | 0.400 in (10.160 mm) |
| 2 | 50 | 2.375 in (60.33 mm) | 0.065 in (1.651 mm) | 0.109 in (2.769 mm) | 0.125 in (3.175 mm) | 0.154 in (3.912 mm) | 0.218 in (5.537 mm) | 0.250 in (6.350 mm) | 8.74mm | 0.436 in (11.074 mm) |
| 2½ | 65 | 2.875 in (73.02 mm) | 0.083 in (2.108 mm) | 0.120 in (3.048 mm) | 0.188 in (4.775 mm) | 0.203 in (5.156 mm) | 0.276 in (7.010 mm) | 0.300 in (7.620 mm) | 0.344 in (8.738 mm) | 0.552 in (14.021 mm) |
| 3 | 80 | 3.500 in (88.90 mm) | 0.083 in (2.108 mm) | 0.120 in (3.048 mm) | 0.188 in (4.775 mm) | 0.216 in (5.486 mm) | 0.300 in (7.620 mm) | 0.350 in (8.890 mm) | 0.438 in (11.13 mm) | 0.600 in (15.240 mm) |
| 3½ | 90 | 4.000 in (101.60 mm) | 0.083 in (2.108 mm) | 0.120 in (3.048 mm) | 0.188 in (4.775 mm) | 0.226 in (5.740 mm) | 0.318 in (8.077 mm) | — | — | 0.636 in (16.154 mm) |
Nominal Pipe Size 4 to Nominal Pipe Size 9
| NPS | DN mm | OD inches (mm) | WT inches (mm) | WT inches (mm) | WT inches (mm) | WT inches (mm) | WT inches (mm) | WT inches (mm) | WT inches (mm) | WT inches (mm) | WT inches (mm) | WT inches (mm) | WT inches (mm) |
| — | — | — | SCH 5 | SCH 10 | SCH 20 | SCH 30 | SCH 40/STD | SCH 60 | SCH 80 | SCH 100 | SCH 120 | SCH 140 | SCH 160 |
| 4 | 100 | 4.500 in (114.30 mm) | 0.083 in (2.108 mm) | 0.120 in (3. 048 mm) | — | 0.188 in (4. 775 mm) | 0.237 in (6.02 mm) | 0.281 in (7.137 mm) | 0.337 in (8.560 mm) | — | 0.437 in (11.13 mm) | — | 0.531 in (13.49 mm) |
| 4½ | 115 | 5.000 in (127.00 mm) | — | — | — | — | 0.247 in (6.274 mm) | — | 0.355 in (9.017 mm) | — | — | — | — |
| 5 | 125 | 5.563 in (141.30 mm) | 0.109 in (2.769 mm) | 0.134 in (3.404 mm) | — | — | 0.258 in (6.553 mm) | — | 0.375 in (9.525 mm) | — | 0.500 in (12.70 mm) | — | 0.625 in (15.875 mm) |
| 6 | 150 | 6.625 in (168.27 mm) | 0.109 in (2.769 mm) | 0.134 in (3.404 mm) | — | — | 0.280 in (7.112 mm) | — | 0.432 in (10.973 mm) | — | 0.562 in (14.27 mm) | — | 0.719 in (18.263 mm) |
| 8 | 200 | 8.625 in (219.08 mm) | 0.109 in (2.769 mm) | 0.148 in (3.759 mm) | 0.250 in (6. 35 mm) | 0.277 in (7. 036 mm) | 0.322 in (8.179 mm) | 0.406 in (10. 312 mm) | 0.500 in (12.70 mm) | 0.593 in (15. 09 mm) | 0.718 in (18.2 6mm) | 0.812 in (20. 62mm) | 0.906 in (23.01 mm) |
Nominal Pipe Size 10 to Nominal Pipe Size 24
| Nominal Pipe Size | DN mm | OD inches (mm) | WT inches (mm) | WT inches (mm) | WT inches (mm) | WT inches (mm) | WT inches (mm) | WT inches (mm) |
| — | — | — | SCH 5s | SCH 5 | SCH 10s | SCH 10 | SCH 20 | SCH 30 |
| 10 | 250 | 10.75 in (273.05 mm) | 0.134 in (3.404 mm) | 0.134 in (3.404 mm) | 0.165 in (4.191 mm) | 0.165 in (4.191 mm) | 0.250 in (6.350 mm) | 0.307 in (7.798 mm) |
| 12 | 300 | 12.75 in (323.85 mm) | 0.156 in (3.962 mm) | 0.165 in (4.191 mm) | 0.180 in (4.572 mm) | 0.180 in (4.572 mm) | 0.250 in (6.350 mm) | 0.330 in (8.382 mm) |
| 14 | 350 | 14.00 in (355.60 mm) | 0.156 in (3.962 mm) | 0.156 in (3.962 mm) | 0.188 in (4.775 mm) | 0.250 in (6.350 mm) | 0.312 in (7.925 mm) | 0.375 in (9.525 mm) |
| 16 | 400 | 16.00 in (406.40 mm) | 0.165 in (4.191 mm) | 0.165 in (4.191 mm) | 0.188 in (4.775 mm) | 0.250 in (6.350 mm) | 0.312 in (7.925 mm) | 0.375 in (9.525 mm) |
| 18 | 450 | 18.00 in (457.20 mm) | 0.165 in (4.191 mm) | 0.165 in (4.191 mm) | 0.188 in (4.775 mm) | 0.250 in (6.350 mm) | 0.312 in (7.925 mm) | 0.437 in (11.100 mm) |
| 20 | 500 | 20.00 in (508.00 mm) | 0.188 in (4.775 mm) | 0.188 in (4.775 mm) | 0.218 in (5.537 mm) | 0.250 in (6.350 mm) | 0.375 in (9.525 mm) | 0.500 in (12.700 mm) |
| 24 | 600 | 24.00 in (609.60 mm) | 0.218 in (5.537 mm) | 0.218 in (5.537 mm) | 0.250 in (6.350 mm) | 0.250 in (6.350 mm) | 0.375 in (9.525 mm) | 0.562 in (14.275 mm) |
| Nominal Pipe Size | WT inches (mm) | WT inches (mm) | WT inches (mm) | WT inches (mm) | WT inches (mm) | WT inches (mm) | WT inches (mm) | WT inches (mm) | WT inches (mm) |
| — | SCH 40s | SCH 40 | SCH 60 | SCH 80s | SCH 80 | SCH 100 | SCH 120 | SCH 140 | SCH 160 |
| 10 | 0.365 in (9.271 mm) | 0.365 in (9.271 mm) | 0.500 in (12.700 mm) | 0.500 in (12.700 mm) | 0.593 in (15.062 mm) | 0.718 in (18.237 mm) | 0.843 in (21.412 mm) | 1.000 in (25.400 mm) | 1.125 in (28.575 mm) |
| 12 | 0.375 in (9.525 mm) | 0.406 in (10.312 mm) | 0.500 in (12.700 mm) | 0.500 in (12.700 mm) | 0.687 in (17.450 mm) | 0.843 in (21.412 mm) | 1.000 in (25.400 mm) | 1.125 in (28.575 mm) | 1.312 in (33.325 mm) |
| 14 | 0.375 in (9.525 mm) | 0.437 in (11.100 mm) | 0.593 in (15.062 mm) | 0.500 in (12.700 mm) | 0.750 in (19.050 mm) | 0.937 in (23.800 mm) | 1.093 in (27.762 mm) | 1.250 in (31.750 mm) | 1.406 in (35.712 mm) |
| 16 | 0.375 in (9.525 mm) | 0.500 in (12.700 mm) | 0.656 in (16.662 mm) | 0.500 in (12.700 mm) | 0.843 in (21.412 mm) | 1.031 in (26.187 mm) | 1.218 in (30.937 mm) | 1.437 in (36.500 mm) | 1.593 in (40.462 mm) |
| 18 | 0.375 in (9.525 mm) | 0.562 in (14.275 mm) | 0.750 in (19.050 mm) | 0.500 in (12.700 mm) | 0.937 in (23.800 mm) | 1.156 in (29.362 mm) | 1.375 in (34.925 mm) | 1.562 in (39.675 mm) | 1.781 in (45.237 mm) |
| 20 | 0.375 in (9.525 mm) | 0.593 in (15.062 mm) | 0.812 in (20.625 mm) | 0.500 in (12.700 mm) | 1.031 in (26.187 mm) | 1.280 in (32.512 mm) | 1.500 in (38.100 mm) | 1.750 in (44.450 mm) | 1.968 in (49.987 mm) |
| 24 | 0.375 in (9.525 mm) | 0.687 in (17.450 mm) | 0.968 in (24.587 mm) | 0.500 in (12.700 mm) | 1.218 in (30.937 mm) | 1.531 in (38.887 mm) | 1.812 in (46.025 mm) | 2.062 in (52.375 mm) | 2.343 in (59.512 mm) |