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.
Commercial Allowance Weight
Transaction Standard
Mass calculations that incorporate a legally defined moisture regain percentage to determine the taxable and billable weight of a fiber shipment prevent financial disputes between buyers and sellers. This calculated mass is the commercial allowance weight, which accounts for the natural moisture variations that occur when raw materials are transported through different climates.
Moisture Correction
Calculating the invoice price of highly hygroscopic fibers like wool, cotton, or viscose requires drying a representative sample in a ventilated oven until it reaches a constant, bone-dry state. Once the dry mass is established, the commercial allowance weight is computed by adding the official percentage of moisture regain prescribed by industry bodies such as the International Wool Textile Organisation. For example, the standard regain for wool is set at eighteen and a quarter percent, which is added to the oven-dry mass.
This adjustment eliminates the financial impact of water absorbed or lost during maritime shipping.
Fiber Class
Synthetic fibers like polyester have much lower official moisture regain values than natural fibers, resulting in smaller adjustments to their shipped mass. The calculation of the commercial allowance weight for these materials uses regains below one percent, reflecting their hydrophobic nature.
Dispute Resolution
Contractual agreements in international yarn trade specify the exact testing standards used to verify the invoiced quantities. If a destination audit reveals a discrepancy, the parties calculate the commercial allowance weight of the delivered lot at an independent laboratory. This procedure resolves weight differences arising from humidity changes during transit.