Determining Customs Tariff Classifications for Raw Linen Fibres
Determining customs tariff classifications for raw linen fibres requires precise physical identification of retting, scutching, and hackling processing stages under HS heading 5301.
Decortication Bench Test
Extraction Benchmark
Laboratory mechanical separation measures the percentage of clean long fibre recovered from unretted or partially retted flax straw samples. Technicians run a decortication bench test on sample bundles to quantify raw fibre yield before processing full shipments through commercial scutching lines. The resulting ratio indicates the mechanical yield potential of unspun raw straw.
Mill intake logs record these test values to establish initial baseline quality for incoming flax straw shipments.
Yield Verification
Mechanical rollers and beating blades strip shive material away from the outer bast layer under standardized machine parameters. Execution of a decortication bench test isolates long fibre bundles without relying on full scale scutching equipment, saving raw material during pre-purchase evaluation. Excessive shive retention in the extracted fibre sample points to incomplete retting or inadequate breaker roller clearance.
Mill technicians compare test readings against historical scutching yields to adjust breaker roll gaps across processing runs.
Processing Boundary
Flax straw with low moisture content breaks easily under impact, causing high fibre loss during mechanical decortication. When decortication bench test results fall below target efficiency values, processing plants recondition raw straw lots in climate controlled storage rooms to restore stem flexibility. The testing procedure applies strictly to raw bast straw and cannot evaluate already scutched tow or combed sliver.
Documented test metrics appear on flax straw procurement certificates to validate commercial lot pricing.