| Nominal diameter (mm) | Age (years) | ||||
| 0 - 10 | 10 - 30 | 30 - 50 | 50 - 70 | >70 | |
| 300 | 120 | 105 | 90 | 85 | 80 |
| 250 | 120 | 105 | 90 | 85 | 80 |
| 225, 200 | 115 | 100 | 90 | 80 | 75 |