Steel pipe sizes can indeed be divided into different schedules, which refer to the wall thickness of the pipes. The schedule number indicates the relative thickness of the pipe wall compared to its diameter.
Schedule Numbering System: The schedule number system, originating from the American National Standards Institute (ANSI), is a standardized scale used to denote the wall thickness of pipes. The most common schedule numbers are Schedule 40, Schedule 80, Schedule 160, and Schedule XXS, among others.
Here is the sch40 catalog for steel round pipes:
| NPS (inches) | Outer Diameter (OD) (mm) | Inner Diameter (ID) (mm) | Wall Thickness (mm) |
|---|---|---|---|
| 0.5 | 21.34 | 15.80 | 2.77 |
| 1 | 33.40 | 26.64 | 3.38 |
| 1.5 | 48.26 | 40.89 | 3.68 |
| 2 | 60.33 | 52.50 | 3.91 |
| 2.5 | 73.03 | 62.71 | 5.16 |
| 3 | 88.90 | 77.93 | 5.49 |
| 4 | 114.3 | 102.26 | 6.02 |
| 5 | 141.3 | 128.19 | 6.55 |
| 6 | 168.27 | 154.05 | 7.11 |
| 8 | 219.08 | 202.72 | 8.18 |
| 10 | 273.05 | 254.51 | 9.27 |
| 12 | 323.85 | 303.23 | 10.31 |
| 14 | 355.60 | 333.35 | 11.13 |
| 16 | 406.4 | 381.00 | 12.7 |
| 18 | 457.2 | 428.65 | 14.27 |
| 20 | 508.0 | 477.82 | 15.09 |
| 24 | 609.6 | 574.65 | 17.48 |
| 30 | 762.0 | 722.33 | 19.84 |
| 36 | 914.4 | 869.95 | 22.22 |
| 40 | 1016.0 | 968.35 | 23.83 |
