STANDARD PIPE SIZES
Pipe come in standard sizes, in a variety of materials including carbon steel, steel alloys and some plastics. The pipe size is specified by two numbers: the nominal pipe diameter (or bore) and the pipe schedule. Knowing these two numbers all necessary dimensions for design and practical use are determined (internal diameter, wall thickness, outer diameter).
| Schedule | Sch. 5 | Sch. 10 | STD(Sch.40) | XS(Sch.80) | Sch. 160 | XXS |
| Nominal Bore 1/2 inch (DN 15 mm), Outside Diameter 21.34 mm | ||||||
| Wall (mm) | 1.65 | 2.11 | 2.77 | 3.73 | 4.78 | 7.47 |
| ID (mm) | 18.04 | 17.12 | 15.80 | 13.90 | 11.78 | 6.40 |
| Nominal Bore 3/4 inch (DN 20 mm), Outside Diameter 26.67 mm | ||||||
| Wall (mm) | 1.65 | 2.11 | 2.87 | 3.91 | 5.56 | 7.82 |
| ID (mm) | 23.37 | 22.45 | 20.93 | 18.85 | 15.55 | 11.03 |
| Nominal Bore 1 inch (DN 25 mm), Outside Diameter 33.40 mm | ||||||
| Wall (mm) | 1.65 | 2.77 | 3.38 | 4.55 | 6.35 | 9.09 |
| ID (mm) | 30.1 | 27.86 | 26.64 | 24.3 | 20.7 | 15.22 |
| Nominal Bore 1.5 inch (DN 40 mm), Outside Diameter 48.3 mm | ||||||
| Wall (mm) | 1.7 | 2.8 | 3.7 | 5.1 | 7.1 | 10.2 |
| ID (mm) | 45.0 | 42.7 | 40.9 | 38.1 | 34.0 | 27.9 |
| Nominal Bore 2 inch (DN 50 mm), Outside Diameter 60.3 mm | ||||||
| Wall (mm) | 1.7 | 2.8 | 3.9 | 5.5 | 8.7 | 11.1 |
| ID (mm) | 56.9 | 54.7 | 52.5 | 49.3 | 42.9 | 38.1 |
| Nominal Bore 3 inch (DN 80 mm), Outside Diameter 88.9 mm | ||||||
| Wall (mm) | 2.1 | 3.0 | 5.5 | 7.6 | 11.1 | 15.2 |
| ID (mm) | 84.7 | 82.9 | 77.9 | 73.7 | 66.7 | 58.5 |
| Schedule | Sch. 5 | Sch. 10 | STD(Sch.40) | XS(Sch.80) | Sch. 120 | Sch.160 | XXS |
| Nominal Bore 4 inch (DN 100 mm), Outside Diameter 114.3 mm | |||||||
| Wall (mm) | 2.1 | 3.0 | 6.0 | 8.6 | 11.1 | 13.4 | 17.1 |
| ID (mm) | 110.1 | 108.3 | 102.3 | 97.1 | 92.1 | 87.5 | 80.1 |
| Nominal Bore 5 inch (DN 125 mm), Outside Diameter 141.3 mm | |||||||
| Wall (mm) | 2.8 | 3.4 | 6.6 | 9.5 | 12.7 | 15.9 | 19.0 |
| ID (mm) | 135.7 | 134.5 | 128.1 | 122.3 | 115.9 | 109.5 | 103.2 |
| Nominal Bore 6 inch (DN 150 mm), Outside Diameter 168.3 mm | |||||||
| Wall (mm) | 2.8 | 3.4 | 7.1 | 11.0 | 14.3 | 18.3 | 22.0 |
| ID (mm) | 162.7 | 161.5 | 154.1 | 146.3 | 139.7 | 131.7 | 124.3 |
| Schedule | Sch.5 | Sch.10 | Sch. 20 | Sch.30 | Sch. 40 | Sch. 60 | Sch 80 | Sch. 100 | Sch. 120 | Sch. 140 | Sch. 160 | XXS |
| Nominal Bore 8 inch (DN 200 mm), Outside Diameter 219.1 mm | ||||||||||||
| Wall (mm) | 2.8 | 3.8 | 6.4 | 7.0 | 8.2 | 10.3 | 12.7 | 15.1 | 18.2 | 20.6 | 23.0 | 22.2 |
| ID (mm) | 213.5 | 211.5 | 206.3 | 205.1 | 202.7 | 198.5 | 193.7 | 188.9 | 182.7 | 177.9 | 173.1 | 174.7 |
| Nominal Bore 10 inch (DN 250 mm), Outside Diameter 273.0 mm | ||||||||||||
| Wall (mm) | 3.4 | 4.2 | 6.4 | 7.8 | 9.3 | 12.7 | 15.1 | 18.2 | 21.4 | 25.4 | 28.6 | 25.4 |
| ID (mm) | 266.2 | 264.6 | 260.2 | 257.4 | 254.4 | 247.6 | 242.8 | 236.6 | 230.2 | 222.2 | 215.8 | 222.3 |
| Schedule | Sch.5s | Sch. 5 | Sch. 10 | Sch.20 | Sch. 30 | Sch. 40s | Sch. 40 | Sch. 60 | Sch. 80 | Sch. 100 | Sch. 120 | Sch.140 | Sch.160 |
| Nominal Bore 12 inch (DN 300 mm), Outside Diameter 323.9 mm | |||||||||||||
| Wall (mm) | 4.0 | 4.2 | 4.6 | 6.4 | 8.4 | 9.5 | 10.3 | 14.3 | 17.5 | 21.4 | 25.4 | 28.6 | 33.3 |
| ID (mm) | 315.9 | 315.5 | 314.7 | 311.1 | 307.1 | 304.9 | 303.3 | 295.3 | 228.9 | 281.1 | 273.1 | 266.7 | 257.3 |
| Nominal Bore 14 inch (DN 350 mm), Outside Diameter 355.6 mm | |||||||||||||
| Wall (mm) | 4.0 | 6.4 | 7.9 | 9.5 | 11.1 | 15.1 | 19.1 | 23.8 | 27.8 | 31.8 | 35.7 | ||
| ID (mm) | 347.7 | 346.0 | 339.8 | 336.6 | 336.6 | 333.3 | 325.4 | 317.5 | 308.0 | 300.0 | 292.1 | 284.2 | |
| Nominal Bore 16 inch (DN 400 mm), Outside Diameter 406.4 mm | |||||||||||||
| Wall (mm) | 4.2 | 6.4 | 7.9 | 9.5 | 12.7 | 16.6 | 21.4 | 26.2 | 31.0 | 36.5 | 40.5 | ||
| ID (mm) | 398.0 | 393.7 | 390.6 | 387.4 | 381.0 | 373.1 | 363.5 | 354.0 | 344.5 | 333.4 | 325.4 | ||
Common used pipe size standards are: American standard (ANSI/ASME/API), European standard(EN, ISO, DIN), British standard (BSP), Japanese standard (JIS). In the American system, the pipe diameter is known as “Nominal Pipe Size” (NPS) or “Nominal Bore” (NB), in the European system it is known as the “Nominal Diameter” (DN) and in British system it is used screw thread type for interconnecting pipes. The pipe schedule sets the pipe wall thickness. Increasing wall thickness of the pipe the mechanical strength of the pipe is increased allowing higher design pressures. Available pipe schedules are (in order of increasing wall thickness): 5S, 10S, 10, 20, 30, 40S, STD, 40, XS (Extra Strong), 60, 80, 100, 120, 140, XXS (Double Extra Strong) and 160. Not all pipe schedules are available for all pipe sizes.
