Ill. Admin. Code tit. 77, § 920.TABLE B
| SIZE | SDR | EXTERNAL DIAMETER | MINIMUM WALL THICKNESS |
| (Inches) | (Inches) | (Inches) | |
| 2 | - | 2.375 | 0.154 |
| 2½ | - | 2.875 | 0.203 |
| 3 | - | 3.500 | 0.216 |
| 3½ | - | 4.000 | 0.226 |
| 4 | - | 4.500 | 0.237 |
| 4½ | - | 4.950 | 0.248 |
| 5 | 21 | 5.563 | 0.265 |
| 6 | 21 | 6.625 | 0.316 |
| 8 | 26 | 8.625 | 0.332 |
| 10 | 26 | 10.750 | 0.413 |
| 12 | 26 | 12.750 | 0.490 |
| 14 | 26 | 14.000 | 0.539 |
| 16 | 26 | 16.000 | 0.616 |
Pipe sizes 2 inches, 2½ inches, 3 inches, 3½ inches, 4 inches and 4½ inches shall be Schedule 40 pipe as a minimum.
(Source: Amended at 18 Ill. Reg. 17684, effective November 30, 1994)