Comparative Life Cycle Assessment of DN355 HDPE Water Pipelines with PN10 and PN16 Pressure Classes

This study presents a comparative, process-based Life Cycle Assessment (LCA) of DN355 HDPE water pipelines with PN10 and PN16 pressure classes. The assessment evaluates the environmental implications of increased pressure rating and the resulting difference in HDPE material requirements. The analysis was conducted using openLCA 2.6.2, with background life cycle inventory data from the European Reference Life Cycle Database (ELCD 3.2) and the IPCC 2021 AR6 impact assessment method. The functional unit was defined as 1 km of installed buried DN355 HDPE water pipeline. The results show that the pipe mass increased from 27.3 kg/m for PN10 to 42.1 kg/m for PN16, corresponding to a 54.2% increase in HDPE material requirement. The calculated GWP100 increased from 24,574.2 to 37,206.0 kg CO₂-eq/km, representing an increase of approximately 51.4%. Contribution analysis identified HDPE production as the dominant contributor, accounting for approximately 94.22% of the PN10 and 96.18% of the PN16 GWP100 impact. In comparison, excavation, backfilling, sand bedding, and other installation activities had substantially smaller contributions. The study highlights the importance of material efficiency and pressure-class selection in reducing the embodied carbon of water infrastructure and demonstrates the application of process-based LCA as a decision-support approach for sustainable pipeline design.