Answer 18: Pipe size is not always equal to our standard catalog size. For more information, please take a look at the following table.
| Size | Inner Diameter (mm) | Outer Diameter (mm) |
| 6 A | 6.5 | 10.5 |
| 8 A | 9.2 | 13.8 |
| 10 A | 12.7 | 17.3 |
| 15 A | 16.1 | 21.7 |
| 20 A | 21.6 | 27.2 |
| 25 A | 27.6 | 34.0 |
| 32 A | 35.7 | 42.7 |
| 40 A | 41.6 | 48.6 |
| 50 A | 52.9 | 60.5 |
