Verifying Mass Balance Recycled Content Claims in Packaging Logistics Files
Verifying mass balance recycled content in packaging requires auditing weighbridge logs, process yields, scope certificates, and credit ledgers across logistics files.
Bulk Sampling ISO 11648
Standard Scope
Standardized sampling protocols define procedures for obtaining representative test portions from heterogeneous particulate materials without systematic bias. The specifications of bulk sampling ISO 11648 govern the statistical design required to draw increments from non-uniform raw material lots such as wood chips or recovered paper bales. Sampling plans established under this framework require increment selection across the entire batch volume to prevent bias.
The protocol ceases to apply once material is fully homogenized into liquid pulp or dissolved solutions.
Statistical Protocol
Sampling accuracy depends directly on increment count and spatial distribution throughout the static or moving stream. Primary increments are harvested at calculated time intervals using mechanical cutters or manual scoops that span the complete stream cross-section. Combining these individual portions creates a bulk sample that reflects the average moisture and impurity content of the consignment.
Secondary reduction steps cut the gross mass down to laboratory testing size while maintaining proportional representation of particle dimensions. Secondary increment division employs rifflers or rotary dividers that split the stream evenly. Measurement uncertainty decreases as the square root of increment numbers increases.
Variance Limit
Error margins in physical lot testing stem primarily from sampling variance rather than laboratory titration or weighing errors. Adherence to bulk sampling ISO 11648 establishes an acceptable variance threshold for contractual acceptance testing between pulp suppliers and paper converting plants.