Can results based on older versions of EF characterization factors be used as input to current LCA models?

The following general principles have been developed for using results based on an expired EF version: 

1. Results based on an old EF version may be used as an input to an EPD based on a newer EF version, if the results can be justified to be identical or conservative. In other words, an EPD based on an old EF version can be used if its use is estimated to yield identical or overestimated results compared to using the newer EF version.
2.  If the results based on an old EF version can’t be justified to be identical or conservative, they can still be used if they are classified as proxy data and can be justified to lead to more accurate results than using available generic data.

The justification for qualifying the use of results based on an old EF version shall be included in the LCA report to make it verifiable. 

Results based on an old EF version cannot be used if the old EF version uses a different impact assessment method with different units. Results based on different units shall never be added together.

If the data source (e.g., an EPD) does not state the EF version used, a conservative assumption shall be made.

If results based on an old EF version have been used as input to a new EPD, we encourage a statement on this tobe included in the EPD. This statement should make it clear that an EPD based on an old EF version has been used as a data source, and that this was assessed to yield identical or conservative results compared to fully using the current EF version.

For guidance on how to interpret the above general principle for the transition from EF3.0 to EF3.1, refer to this article.

More guidance on this topic will soon be added to https://www.environdec.com/methodology.