Customs Classification and Regain Adjustments for Imported Bast Fibre Shipments
Core sampling imported bast fibre bales for ISO 6741 oven-dry mass adjustments corrects valuation entries and prevents duty overpayment on water weight.
Shive Content Threshold
Purity Standard
Industrial quality limits define the maximum allowable proportion of woody bark fragments remaining in processed bast fibers before spinning. The shive content threshold determines whether a batch of flax fiber is clean enough for fine yarn production. It differentiates between high-value long line fiber and lower-grade tow.
Measurement Method
Laboratory technicians extract a sample of raw fiber and manually separate the woody shives from the usable cellulose fibers. They weigh both fractions to calculate the percentage of contamination in the batch. If the sample exceeds the specified limit, the fiber cannot be spun into fine warp yarns due to the risk of frequent breaks.
This test ensures that the raw material matches the spinning requirements of the mill.
Yarn Quality
Maintaining low shive levels prevents machinery wear and improves the hand feel of the finished linen fabric. Woody particles that bypass the cleaning process create thick spots and weak points in the yarn, leading to frequent breakages on the loom. When a batch fails to meet the required threshold, it is redirected to coarser products like twine or heavy industrial canvas.
This quality control measure protects the mill’s spinning efficiency and preserves the aesthetic appeal of the final woven linen.