Testing of tops and sliver

Independent certification of tops or sliver to IWTO standards is uncommon, primarily because sampling is best undertaken throughout production, which would require long periods of independent supervision. Historically, topmakers and their clients have established trust relationships based on mill certification using the mill QC laboratory. IWTO has licensed some of these laboratories to issue IWTO Certificates.

Nevertheless, SGS Wool Testing Services does issue independent test reports and certificates on consignments of tops and sliver where these are required by the buyers. These are routinely required for some specific countries such as Iran. Specialised testing is required for conformity assessment on wool tops and polyester-wool blend tops - a TCO brochure (PDF 649 KB). It is critical that we are contacted as early as possible in order to arrange sampling in the most convenient and cost-effective manner.

Common test requirements include:

• Condition (moisture content)
• Fibre diameter
• Fibre length
• Residues (dichloromethane-soluble matter, "fatty matter", NPEO detergents)
• Sliver weight/density
• Sliver composition (blends)
• Sliver quality (neps, dark fibres, medullated fibres, vegetable matter)

Less frequently, measurements are required and can be provided on properties such as color, evenness and fibre strength.

Please contact us for information regarding sampling should this service be required.