To be able to fulfil high market expectations for a number of practical applications, EPDs have to meet and comply with specific and strict methodological prerequisites. These expectations include the possibility to add up LCA-based information in the supply chain and to compare different EPDs. To achieve this goal, common and harmonised calculation rules have to be established to ensure that similar procedures are used when creating EPDs.

However, groups of products, usually differ in their inherent environmental performance requiring specific rules to the product group, so-called Product Category Rules (PCR) to be prepared. The PCR documents shall be regarded as complementary to general requirements of EPD programmes.

Trade of products and services often extends national borders which call for a need to harmonise the PCR documents being prepared in various countries by different companies and branch organisations as well as independent bodies operating or implementing EPD programmes.