# System model definitions

## Definitions

| System model  | Definition                                                                                                                                                                                                             |
| ------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| CUT_OFF       | Cut-off system model. Environmental burdens are assigned according to the database's cut-off, allocation and recycling rules.                                                                                          |
| CONSEQUENTIAL | Consequential system model. Describes changes in the product system caused by a decision, including affected supply and substitution relationships.                                                                    |
| EN_15804      | System model for EN 15804 requirements. The applicable standard edition, life cycle modules, allocation rules and category indicators are specified in the implementation documentation for the corresponding version. |