How do I verify whether my supplier's data is correct?

Reliable test methods and the prohibition on circumvention are the starting point

Anyone wishing to check whether a supplier's data are correct can focus on two things: the manner in which those data were produced, and the question of whether a product behaves differently during a test than in normal use. Article 39 of the ESPR (Regulation (EU) 2024/1781) sets requirements for the test, measurement and calculation methods used to demonstrate that a product complies with ecodesign requirements: those methods must be reliable, accurate and reproducible. Article 40 then prohibits designs intended to influence the outcome of such a test, or which worsen the performance of a product without the user being informed thereof. A supplier providing data thus effectively provides an outcome of a method — and that method is the point at which control applies.

For which data this applies, and for which it does not

These two articles concern data used to demonstrate that a product complies with ecodesign requirements established via a delegated act — think of matters such as fibre composition, durability or other characteristics that end up in the product passport. They do not concern general commercial information such as price, delivery time or contract terms, nor do they concern an obligation for a brand or importer to conduct laboratory testing itself. The articles focus on the quality of the underlying measurement method and on the prevention of deliberate manipulation, not on a general due diligence framework for supplier assessment. Anyone looking for an obligation to audit suppliers or a list of approved testing institutes will not find it here — that is a different matter from what these two articles regulate.

No fixed date yet, but a fixed order

No delegated act has yet been published that specifically establishes which ecodesign requirements are to apply to clothing and textile products and from when. What is fixed: in the work programme of the European Commission for 2025-2030, a delegated act for textiles is scheduled for 2027, and clothing with eighty per cent or more textile fibres is named as the first category. Once that act is published, the date from which this becomes concrete for clothing will be shown here. Until then, Article 39 and 40 apply as the general framework within the ESPR: the rules on reliable methods and the prohibition on circumvention are already in place, but the implementation for textiles — which properties exactly must be measured and according to which standard — is still to follow.

How to approach this in practice

Anyone wishing to review supplier data should start by asking about the source of a figure or claim: on the basis of which test, measurement or calculation was this established, and according to which standard or method. A supplier who can substantiate that with a test report or certificate already provides a first point of reference for reliability — Article 39 after all requires methods that are reproducible, meaning that another party must be able to arrive at the same result. A second step is to watch for signs that a product performs differently under test conditions than in normal use, or that a software or process update can change the properties of a product without this being notified — that is precisely what Article 40 is aimed at. A third step is to keep the supporting evidence: not just the final figure, but also the report or the method on which it is based, so that it can be retrieved later if asked for. For the digital product passport, the data that ultimately appear in the passport must be traceable to a source — what that source looks like and how robust it must be is precisely where these two articles set the bar.

Where this is found: Article 39 and 40 of the ESPR

The requirement that test, measurement and calculation methods must be reliable, accurate and reproducible is set out in Article 39 of Regulation (EU) 2024/1781. The prohibition on circumvention — designing a product so that it performs differently during a test than in practice, or undisclosed deterioration of performance through an update — is set out in Article 40 of the same regulation. Both articles are part of the general framework of the ESPR and apply to all product groups for which ecodesign requirements are established through a delegated act, including textiles and clothing once the specific act is in place.

Those who already work with suppliers can do well to ask for the underlying test method and the associated report for every claim or specification, and to keep them together with the rest of the product data. Once the delegated act for textiles has been published, this page will be updated with details of which requirements specifically apply and which standards are associated with them.