Calculating Dehairing Yield Mass Balance across High Guard Hair Batches
Calculate dehairing yield by converting raw mass to clean dry keratin weight, subtracting guard hair and dirt losses, and normalizing to 17% commercial regain.
IWTO-58 Assay
Wool Certification
International testing protocols for measuring the percentage of clean wool fiber present in a raw, greasy fleece shipment establish the legal invoice mass of the traded commodity. This standard test method is the iwto-58 assay, which utilizes gravimetric measurements of cleaned wool samples to determine the commercial yield.
Commercial Value
Transactions in the global wool trade are based on the clean wool content rather than the raw weight, which includes heavy grease, sweat, dirt, and vegetable matter. Running the iwto-58 assay ensures that the buyer pays only for the actual usable fiber in the shipment. This laboratory test involves scouring a raw sample, extracting residual grease with organic solvents, and drying the fiber to determine its oven-dry weight.
By standardizing these measurements, the international wool trade avoids disputes over moisture and impurity levels in bulk shipments.
Standard Procedure
Clean wool yield calculations require the addition of a standard moisture regain and an allowance for minor residual grease. The iwto-58 assay provides the official yield percentage that is printed on international test certificates for every traded lot of raw fleece.
Mill Processing
Spinning mills rely on these test certificates to calculate the actual cost per kilogram of the fiber they put into production. The results help the mill manager estimate the amount of waste that will be generated during the scouring process.