Recycled Polyester Content Held as Mass Balance against Segregated Stock
Customs compliance requires physical composition testing while brand claims rely on audited mass balance ledgers, forcing buyers to manage separate verification streams.
Allocation Models
Definitional Framework
Regulatory frameworks for assigning environmental attributes to specific output batches in a chemical recycling or mass balance system. Allocation models determine how recycled content claims are distributed across a mill’s product range when physical segregation is impossible. These methods apply primarily to polyester and polyamide production where monomer streams from waste and virgin sources are blended.
Mathematical Logic
Calculation logic dictates whether credits are spread evenly or concentrated on specific high-value items. Mass balance allocation models ensure that the total weight of claims leaving the site never exceeds the weight of certified inputs entering the facility. This verification happens during third-party audits of the site inventory.
The auditor checks the mass balance period, which usually spans three months or a year, to confirm that input and output volumes align after accounting for production waste and process losses.
Operational Boundary
Specific boundaries define where the substitution of materials occurs within the refinery or polymerization unit. Physical properties of the resulting yarn do not change based on which allocation models the producer applies. Verification remains purely administrative.
Claim Integrity
Transparency requirements prevent the double counting of environmental benefits across different jurisdictions. If a mill uses site-level allocation, it must account for losses during the extrusion and spinning phases to maintain the credibility of the final transaction certificate. Reliability rests on the audit trail.