Resolving Discrepancies between Laboratory Oven Dry Weights and National Tariff Regain Tables
Reconcile dock scale variances by calculating commercial mass from clean oven-dry weight plus statutory tariff regain schedules rather than ambient mass.
Statutory Moisture Regain
Regulatory Standard
Legally defined percentage of moisture that is added to the anhydrous mass of a fiber to determine its commercial weight for trade. International agreements specify the statutory moisture regain for every major fiber type to ensure fair pricing in global markets. This fixed value replaces the actual, fluctuating moisture content of the material at the time of weighing.
Calculation Method
Sellers calculate the invoice weight by taking the oven-dry mass of the shipment and increasing it by the officially recognized regain factor. For example, cotton has a statutory moisture regain of 8.5 percent, while polyester is much lower at 1.5 percent. This system removes the financial incentive for suppliers to store fiber in damp conditions to artificially increase its weight.
Invoicing Accuracy
Transactional documents must state the regain used so that the buyer can verify the math against independent lab results. Any discrepancy between the laboratory report and the invoice regain can lead to a formal price adjustment.
Laboratory Condition
Verification of these figures requires the sample to be conditioned in a standard atmosphere of 20 degrees Celsius and 65 percent relative humidity. Although the actual moisture in the sample might differ slightly from the legal definition, the statutory moisture regain remains the only figure used for the final commercial settlement. This consistency allows for predictable costing across different climates and shipping routes.