ISO 22095 Mass Balance Chain of Custody Audit Requirements
ISO 22095 mass balance audits demand strict site boundaries, verified baseline yield conversions, and zero negative credit balances across accounting periods.
Proportional Allocation Rules
Meaning
A set of accounting principles governs the distribution of sustainable attributes across co-products and product grades based on their relative mass or energy content. These proportional allocation rules prevent the arbitrary concentration of recycled claims on a single high-value polymer grade when processing a mixed batch. Processors must apply these guidelines to ensure that each output grade receives a share of certified credits that reflects its actual proportion in the output mix.
This method prevents the manipulation of sustainability claims for commercial advantage.
Material Efficiency
In a chemical recycling plant, the pyrolysis of mixed plastic waste yields various hydrocarbon fractions. Under proportional allocation rules, the recycled polymer credits must be distributed across these fractions in proportion to their yield. This prevents the producer from allocating all recycled attributes to the high-demand polyethylene fraction while ignoring the heavier waxes and oils.
This approach keeps the material claims aligned with the chemical reality of the conversion process.
Production Limit
For injection molders, these constraints govern how runner scrap and regrind are credited during a production run. Applying proportional allocation rules ensures that if a run produces both high-weight and low-weight parts from the same mold, the recycled credits are distributed according to the mass of each part. This constraint prevents the processor from declaring only the most expensive parts as recycled while calling the others conventional.
This limits the flexibility of credit distribution but ensures absolute transparency. It also forces molders to seek certified status for all products generated during the run rather than cherry-picking high-value items.
Financial Consequence
These distribution constraints affect the profitability of recycled product lines. By enforcing proportional allocation rules, certification bodies limit the ability of molders to maximize profits by putting all sustainable credits into their highest-margin products. Moulders must manage their product portfolios carefully to ensure that all certified grades find viable markets.