Standard Scope
An international testing specification defines cross-sectional microscopic procedures for quantifying component proportions in blended plant fiber materials. Standard iso 20705 establishes the laboratory framework for differentiating flax fibers from hemp fibers in yarn and fabric samples through cross-sectional morphological evaluation. The document governs testing protocols across commercial linen supply chains where species verification determines trade compliance.
Its scope stops at chemical fiber blends where synthetic polymers replace natural bast structures.
Microscopic Protocol
Specimen preparation begins with embedding yarn or fabric cross-sections in synthetic resin blocks. Thin sections cut with a microtome expose transverse fiber profiles under high-resolution optical or digital light microscopes. Analysts evaluate lumen dimensions, cell wall thickness and cross-section polygon shapes across multiple randomized sampling fields.
Statistical counts of observed cell geometries yield percentage mass ratios for each fiber species in the test sample. Standardized stain reagents highlight cell wall structures to ensure clear visual separation between bast fiber types. Cross-sectional area calculations convert numerical counts into accurate mass percentage figures reported on official test certificates.
Trade Verification
Customs authorities and commercial test houses rely on standardized test results to verify declared fiber contents on shipping invoices. Discrepancies between declared pure linen status and detected hemp content lead to reclassification of fabric shipments at import terminals. Test reports generated under this standard protect buyers against fraudulent fiber substitution in high-value textile contracts.
Mill quality departments archive test certificates alongside mill production records to satisfy buyer audit requirements.
