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Operating to International Wool Textile Organisation (IWTO) standards, SGS provides a range of independent laboratory tests on scoured wool to help verify quality and quantity.

Our scoured wool measurement services include certified tests for:

  • Conditioned mass – wool absorbs up to 20 percent of its weight as moisture so invoicing is based on an agreed moisture content or regain (known as the conditioned mass)
  • Yield – determining the amounts of clean wool (woolbase), and vegetable matter contamination in a sample
  • Mean fibre diameter – the average fineness of the wool (fibre thickness), which is a primary determinant of wool value 
  • Colour – measured as tristimulus values, and normally used to assess clean colour brightness (Y value) and yellowness (Y-Z value)

In addition, we certify a large proportion of scoured wool for Length After Carding (LAC). To do this, we use a standardised method of simulating semi-worsted processing to estimate mean fibre length after processing. We also test for:

  • Residuals – the amount of mineral matter and residual grease left on the fibres after scouring, indicating scouring efficiency
  • pH – the acidity or alkalinity of the wool after scouring affects the dyeing process, so it is important for processors to know the pH value
  • Alkali solubility and extent of bleaching – solubility is used to assess fibre damage, while the extent of bleaching is important in some processes
  • Medullation – refers to the hollow fibres in wool and other animal fibres, which causes uneven dye uptake and adversely affects appearance in apparel wools (but may be desirable for some carpet types)
  • Bulk – this measures the fibres’ ability to fill space and also relates to resilience, which are important properties for applications such as carpets, futons and insulation
  • Fibre curvature – relates to bulk, compressibility and crimp and is cited as an influence on processing
  • Fibre diameter distribution – information about aspects of the diameter distribution may affect assessments of comfort and processing performance
  • Detergent residuals – wools intended for certain markets must be scoured with detergents that do not contain nonyl phenol ethoxylate (NPEO)
  • Mothproofing treatments – these must comply with the appropriate regulations
  • Sanitary reports – shipments to certain destinations require an inspection report confirming that any residual vegetable matter is non-viable, while other places may require sanitisation procedures to be verified
  • Exports to Iran – these shipments require conformity assessment involving specialised testing to Iranian Standards

To verify the quality and quantity of scoured wool across a range of criteria, contact SGS now to ask about our independent testing services.