May conversion factors be included in the EPD?

Yes, conversion factors may be included for the purposes of: 

1. converting the declared results of a product group to results for specific products within the group, or
2. converting the declared results to results for another declared/functional unit.

For the first of the above two purposes, the declared conversion factors can be applicable for the results of all declared modules or for a subset of modules (e.g., A1-A3), and for all declared indicators or for a subset of indicators (e.g., the GWP-total indicator). Such limitations in the applicability of the conversion factors shall be clearly stated in the EPD. For the modules and indicators to which the conversion factors are applicable, the results shall scale linearly with the conversion factor. 

The conversion factors shall be expressed as multiplying factors. In other words, the declared results can be multiplied with the conversion to calculate the results per specific product or another declared/functional unit. 

The conversion factors shall be verifiable, i.e., the underlying data for the conversion factors shall be provided in the LCA report. 

The conversion factors shall be included in the section with additional environmental information (see Section 7.4.8), although they may be referred to in the environmental performance section. 

Conversion factors can, however, not be included for the purpose of converting the declared results into results for products not covered by the EPD. The EPD is for a specific product or product group, and only the EPD content of that product/product group has been verified and may be considered EPD information. 

The above rules are from version 5.0.0 of the General Programme Instructions (GPI). PCRs based on an older version of the GPI may have deviating rules.