| Code | Description | Comment | Version |
| 1 | ASTM Level 1 | deprecated | added v2.3, removed after v2.3 |
| 2 | ASTM Level 2 | deprecated | added v2.3, removed after v2.3 |
| 3 | ASTM Level 3 | deprecated | added v2.3, removed after v2.3 |
| R | Restricted | | added v2.3.1 |
| RE | Restricted | deprecated | added v2.3, removed after v2.3 |
| U | Usual control | | added v2.3.1 |
| UC | Usual control | deprecated | added v2.3, removed after v2.3 |
| V | Very restricted | | added v2.3.1 |
| VR | Very restricted | deprecated | added v2.3, removed after v2.3 |