To substantiate the fiber composition in a digital product passport, you typically need four types of documents: the supplier's declaration in which the manufacturer specifies the composition per fiber, the technical specification or fabric sheet that accompanies the order, a laboratory report when there is doubt about a percentage, and any certificates from a quality mark if that is mentioned on the label. Together, these documents form the substantiation behind the percentage that will appear in the passport.
The point where this often gets stuck in practice is not the individual fiber but the blend. A label reading '60% cotton, 40% polyester' looks straightforward, but the question of who determined that percentage and on the basis of which test is rarely provided. For the passport, it is not only what appears on the label that matters, but also whether that percentage is traceable to a source. This detail is more important for fiber composition than for other parts of the passport, because blends are the norm in clothing and pure fibers are the exception.
What is on the list
The core of the list consists of four documents. First, the declaration from the manufacturer or supplier, which specifies the fiber composition per part of the garment: outer fabric, lining, and where relevant applications or seams. Second, the technical specification that accompanies the purchase order and in which the yarn composition is fixed before the product is produced. Third, a laboratory report, which you do not need for every article but do need in case of doubt, with a new blend, or when the supplier itself cannot provide substantiation. Fourth, certificates from quality marks that say something about the fiber itself, such as origin or processing, insofar as that claim is also used on the label or in marketing.
These documents partly overlap with what you already gather for labeling textiles under existing rules. If you already have that process in order, you do not need to start from scratch; the question is mainly whether the substantiation per article is kept and linked, rather than only appearing on the label.
Why blends are the most difficult part
With a pure fiber, such as one hundred percent cotton, the substantiation is usually brief: one declaration from the spinner or weaver is sufficient. With a blend, it is different. The percentage can vary slightly per batch of yarn, especially with recycled or natural fibers where the raw material itself is variable. The regulation does not explicitly distinguish here between percentages indicated 'roughly' and 'precisely', but supervisory authorities look, in case of doubt, at whether the stated percentage is demonstrable. This makes it more important for blends to keep substantiation per batch, and not only per article number.
What if the composition varies per batch
It can happen that a collection is sold under one article number, while the fiber composition per production batch varies slightly, for example due to a different yarn supplier. In that case, the question is what level of detail the passport should display, and whether one article passport is sufficient or whether an adjustment is needed. This is one of the points on which the delegated act must still provide clarification; at present, this has not been established. For your own situation, it is advisable to discuss this with a lawyer or with the competent supervisory authority, and not to decide on the basis of assumptions.
Where you bring these documents together
In practice, these documents come from different parties: the yarn supplier, the garment manufacturer, and sometimes an external laboratory. Keeping track of who has supplied which document and whether that document is still current is precisely where maintaining a passport breaks down in practice if it remains scattered across folders and mailboxes. In the knowledge base by subject, we have worked out you can read how other parts of the passport, such as origin and care instructions, relate to this documentation.
Whether your own system is suitable for linking these documents to an article is a question you can best address directly to your software supplier. How we proceed shows which step is standard with us and which remains with you. If you are unsure whether your current administration already meets what will soon be required, it provides the free quick-scan answers a few questions with an initial indication from where you stand.
Do you have questions about a specific case, for example a blend with a fluctuating percentage or a supplier who refuses to provide a declaration? Then consult the overview of frequently asked questions, or discuss the situation with a lawyer or the competent supervisory authority. If you would like a general overview first, take the free quick-scan or browse through the subjects in the knowledge base.