Environmental Product Declarations: Effects of Scope of Consideration and Design Approach on the Results of Life Cycle Assessments

One challenge in using Environmental Product Declarations (EPDs) effectively in construction projects is ensuring the standardization of Product Category Rules (PCRs) and Life Cycle Assessments (LCAs) so that comparable products are evaluated consistently. When conducting LCAs for construction projects, alternative design approaches often involve the substitution of products from different categories to achieve the desired result. In this scenario, an analysis which simply compares the EPDs of the alternative products may yield flawed results because the differing design approaches will have effects which extend beyond the products themselves. To capture a true comparison of the environmental impacts, the scope of consideration for the LCAs must extend beyond the EPDs and account for all impacts resulting from each design approach. The importance of adopting a proper scope of consideration for LCAs can be demonstrated through the example of a flexible pavement with alternative designs using a conventional approach and a mechanically stabilized aggregate layer for enhanced performance. Sample analyses are presented showing the effects of the scope of consideration and the sensitivity of the results to the variables considered. The objective of the study is to highlight key considerations for accurate LCAs, the importance of establishing standard factors and approaches, and the necessity of a comprehensive approach.