Getting Fibre Composition Data Right

Fibre composition is the attribute every textile company assumes it already has. It is printed on a label sewn into every garment, it has been a legal requirement for years, and the factory supplies it as a matter of routine.

It is also the attribute that textile passport programmes most often fail on, because the number on the label and the number a passport needs are answering different questions.

What the label is allowed to leave out

Regulation (EU) No 1007/2011 governs textile fibre names and labelling. It requires the fibre composition of the main body of the product, and it permits several exclusions that are entirely reasonable for a consumer label and unhelpful for a material record.

Visible, isolable decorative fibres below a threshold can be excluded. Certain trims, fastenings and stiffenings sit outside the declared composition. A garment can therefore carry an accurate label stating one hundred per cent cotton while containing polyester thread, an elastane-blended waistband and a coated interlining.

None of those exclusions are loopholes. They exist because a consumer label is a purchasing aid, not a recycling specification. The passport is closer to the second, which is why the data has to be rebuilt rather than copied.

Why the recycler cares about the difference

Fibre-to-fibre recycling is sensitive to contamination in ways that are counterintuitive if you have only worked upstream. A cotton garment with polyester sewing thread is not a cotton input; it is a mixed input that a mechanical recycler must either separate by hand or downgrade.

The economics follow directly. Separating trims manually costs more than the recovered fibre is worth for most garments, so a mixed item goes to a lower-value route regardless of what its main fabric is. Composition data that omits the contaminating three per cent tells the recycler nothing they can act on.

Recycled content needs its own treatment

Where a fibre is recycled, stating the percentage is not sufficient. Three further facts determine whether the claim is defensible.

• Pre- or post-consumer. Both are legitimate, they are not equivalent, and most targets are written against post-consumer content specifically.
• Chain-of-custody model. Segregated content is physically present; mass balance means an equivalent quantity entered the system somewhere. Publishing one as the other is the claim most likely to be challenged.
• The certification behind it. A recycled polyester claim supported by a chain-of-custody certificate is evidence; the same claim from a supplier declaration is an assertion, and the passport should record which it is.

The failure mode here is a single "45 % recycled" figure with none of that context. It reads as precise, survives until somebody asks how it was calculated, and then unravels in front of the customer who published it downstream.

Where in the chain the data goes stale

Composition data usually originates at the mill and is passed downstream unchanged. The problem is that several stages after the mill can alter what the material actually is.

The practical consequence is that the composition attribute cannot be sourced from one supplier. It has to be assembled, with the making-up stage contributing the components that the mill never saw.

How to collect it so it holds up

Four changes to the data request produce most of the improvement, and none of them require new systems.

1. Ask for composition by component rather than for the garment, listing body fabric, lining, thread, trims, interlining and labels as separate rows.
2. Ask for mass per component, not only percentages, because percentages of unknown masses cannot be aggregated correctly.
3. Ask the making-up factory rather than the mill for anything added after weaving, since the mill has no visibility of it.
4. Require the chain-of-custody model and certificate reference alongside any recycled percentage, in the same row rather than as an attachment.

What this unlocks beyond compliance

Component-level composition is the input to several things a brand usually wants anyway. Recyclability assessment becomes computable rather than estimated. Design decisions about thread and trim selection acquire a measurable consequence. Producer responsibility fees, where eco-modulated, respond to exactly this data.

It is also the attribute that makes a resale or repair proposition credible, because a second owner asking whether a garment can be repaired is really asking what it is made of and whether the parts can be separated.