Explicit accounting methods for recycling in LCI

The life cycle inventories (LCIs) of recyclable and recycled materials can be strongly affected by how the savings from recycling are accounted. Unfortunately, most LCI methodologies do not explicitly address the important and subjective question of how to allocate inputs and outputs between primary and secondary material. This paper describes an LCI methodology that enables the analyst to explore and define the accounting rules more explicitly. Examples are developed to demonstrate the workings of the methodology and its implications for materials selection.