EN 13432 and Compostability Certification: What the Standard Actually Tests

EN 13432 is the standard that defines compostability for packaging, and certification to it tests the finished material or article against four gates. Biodegradation: the organic fraction converts to carbon dioxide under composting conditions within the standard's period (90 percent within six months is the benchmark shape). Disintegration: the article physically breaks down in a composting trial, leaving no more than a small residue above the sieve size after twelve weeks. Ecotoxicity: the resulting compost must not impair plant growth - the compost is tested, not just the material. And chemical limits: heavy metals and other constituents below the standard's thresholds. Certification bodies (the seedling-mark ecosystem and its peers) test and license the marks per product, per thickness, per formulation.

This guide reads the four gates as a buyer and a specifier must.

Compostability is a property of the article as made, not of the polymer as sold. The same certified resin fails at greater thickness (disintegration is a race between breakdown and time, and thickness is time's ally), with the wrong ink coverage, or with an adhesive the resin certificate never met. Certificates therefore name the article, its maximum thickness and its formulation family; the buyer's check is the scope discipline of the certification station applied exactly - does this certificate cover this article, at this gauge, with these inks and adhesives, from this production process? Converters reformulating inside a certificate's family need the body's rules on variants, in writing. The market's commonest compostable finding is a genuine certificate for a different article, honestly believed to travel. It does not.

Three silences matter. It does not say the item will compost in your customer's local facility: industrial composting conditions (temperature profiles, residence times) vary, and some operators screen out even certified items whose real-world disintegration lags their process - the infrastructure guide's acceptance problem. It does not say anything about littering or the marine environment: compostable is not a licence to discard, and claims suggesting otherwise breach the claims framework the labelling station policed. And it does not say the item belongs in any other stream: in plastics recycling it is a contaminant, in landfill it is inert-ish waste, in the garden it is (unless home-certified) a slow guest. The certificate certifies a destination; the label and the system must deliver the item to it.

Certification testing runs on biological time: the disintegration and biodegradation gates take months by design, and the certification calendar must be planned accordingly - a format converting for February 2028 needed its testing programme in 2026-2027, and late starters will queue behind the season's whole industry at the same laboratories. Budget the ecotoxicity and metals gates' iterations too: ink and adhesive changes late in development can reopen the file. The commercial consequence generalises beyond this family: under the PPWR, biological and evidentiary clocks (composting trials, recycling tests, authorisation processes) set the real deadlines, and programmes planned on commercial clocks alone discover them in order.

Certification does quiet work beyond the gate: it gives the whole chain - resin maker, converter, brand, retailer, composter - a shared, testable vocabulary for a property none of them can see. The chains that use it well treat the certificate the way the conformity station treats the declaration: scoped, versioned, retrievable, and re-checked when anything in the formulation moves. The chains that treat it as a logo discover its meaning in a dispute. Compostability is invisible; the paperwork is the product's only visible form of it.

Every other certification in this regulation can be accelerated with money - more laboratories, more shifts, more samples. Composting cannot: the organisms work at their pace, and the standard's durations are their biography, not bureaucracy. Programmes that respect the biological clock (testing started early, formulations frozen during trials, iterations budgeted) convert calmly. Programmes that discover it in the final year discover that February 2028 does not negotiate, and that the organisms were never told about the launch date.