Fibre Composition Testing and Label Tolerance: EU and US Rules

The 3% tolerance, rule by rule

Sources: Regulation (EU) No 1007/2011 (text read from the adopted version) and 16 CFR Part 303.

Why the EU result can differ from the dry weight

EU checks dissolve and weigh each fibre dry, then add an agreed allowance for the moisture each fibre normally holds. Annex IX sets 8.5% for normal cotton, 10.5% for mercerised cotton, 13% for viscose, modal and lyocell, and 1.5% for polyester and elastane. Absorbent fibres gain weight on this basis; polyester barely changes.

A worked example with a cotton and polyester blend. The lab finds 58.0 g of dry cotton and 42.0 g of dry polyester in every 100 g of dry fibre:

The figures in this example are worked from Annex IX, not from a real test. The point is the basis: ask the lab to report the percentages the way the destination market calculates them, and state the basis on the report.

What else an EU fibre label must get right

• Components: a product with two or more textile parts of different fibre content states the content of each part. Parts that are not main linings and weigh less than 30% of the product are exempt (Article 11).

• Decorative and antistatic fibres: visible decorative fibres up to 7% of the finished weight, and antistatic or metallic fibres up to 2%, can be left out of the composition (Article 10).

• Animal parts: leather trims or fur need the phrase "Contains non-textile parts of animal origin" (Article 12).

• Durable label: the label must be durable, easily legible, visible and accessible, and securely attached (Article 14).

• Online: the fibre composition must be visible to the consumer before purchase, including online (Article 16).

• Who answers for it: where the manufacturer is outside the EU, the importer ensures the label is supplied and accurate (Article 15). For goods exported from Pakistan, that is the EU importer.

What else a US fibre label must get right

• Generic names: manufactured fibres take the generic names set by the FTC, including those in ISO 2076:2013 (§ 303.7). Rayon made from bamboo is rayon.

• Country of origin and RN: the label carries the country where the product was made and the name or RN number of a company that handles it (§ 303.16).

• Neck label: a product with a neck carries the country of origin inside the centre of the neck (§ 303.15).

• English: all required information appears in English (§ 303.4).

Fibre names are enforced. On 8 Apr 2022 the FTC announced US$5.5 million in civil penalties against Kohl's (US$2.5 million) and Walmart (US$3 million) for selling rayon textiles as bamboo, after 2010 warning letters (FTC).

How the lab measures fibre content

Fibre analysis runs in two steps. Qualitative analysis identifies which fibres are present, by physical, chemical and microscopic techniques (AATCC TM20). Quantitative analysis then measures how much of each there is, usually by dissolving one fibre out of the blend with a chosen reagent and weighing the residue (the ISO 1833 series and AATCC 20A).

Each part of ISO 1833 covers particular blends. ISO 1833-11, for example, uses sulfuric acid to separate cellulose fibres such as cotton, viscose, modal and lyocell from polyester and polypropylene, which covers polyester and cotton blends. Because it dissolves every cellulose fibre, a blend of cotton with viscose needs a different part.

Every method below is on the Tti Labs ISO/IEC 17025 scope (PNAC LAB-022):

Where label failures start

• Yarn lots differ. The blend in a bulk yarn lot can differ from the lot used for the sample. Test the yarn lot used in bulk, not only the lot used for the sample.

• Trims and linings are forgotten. Pocketing, linings and ribs of a different fibre count as separate components in the EU.

• Elastane is dropped. A small stretch content still has to be declared in the EU; in the US it can only be named under 5% where it has a functional purpose, as stretch does.

• Marketing names replace fibre names. "Bamboo", "silky" or a brand name is not a fibre name. The composition uses the names the law lists.

• One label for every market. The same fabric can test within 3% on the EU basis and outside it on dry mass, or the other way round.

The clause to write into the order

• "Fibre content to be stated as [60% cotton, 40% polyester]. Tolerance 3 percentage points of total fibre weight. Test by ISO 1833 (EU orders, with Annex IX agreed allowances) or AATCC 20A (US orders) on a specimen from the bulk production lot."

• "Each textile component with a different fibre content to be tested and labelled separately."

• "Fibre names as listed in Annex I of Regulation (EU) No 1007/2011 or 16 CFR Part 303, with no trade or marketing names in the composition line."

Tti Labs tests fibre content in Lahore

Tti Testing Laboratories holds ISO/IEC 17025 accreditation under PNAC LAB-022, valid until 8 Aug 2027, for every method in the table above. Each test and its charge are confirmed in writing, with the turnaround, before any work starts (Tti Labs testing). The textiles testing page lists the other textile methods, the lab testing guide covers how to plan a test programme, and label checks at pre-shipment inspection confirm the right label went on the goods.

Book a fibre composition test with Tti Labs