What is the difference between EN 13432 and ASTM D6400 for molded pulp packaging?

EN 13432 (EU) and ASTM D6400 (US) are the two dominant industrial composting certification standards for biodegradable packaging — including molded pulp. Both require ≥90% biodegradation within 180 days, ≥90% disintegration into fragments <2mm within 12 weeks, no negative effects on compost quality (eco-toxicity testing), and heavy metal concentrations below specified limits (Zn <150 mg/kg, Cu <50 mg/kg, Ni <25 mg/kg, Cd <0.5 mg/kg, Pb <50 mg/kg, Hg <0.5 mg/kg, Cr <50 mg/kg, Mo <1 mg/kg, Se <0.75 mg/kg, As <5 mg/kg, F <100 mg/kg). The key difference: EN 13432 also requires ≥90% biodegradation for each individual organic constituent above 1% mass, while ASTM D6400 assesses the product as a whole. Molded pulp (uncoated, no additives) meets both standards without modification. PFAS-free water-based barrier coatings at <5% by weight typically maintain compliance.

Does molded pulp packaging need certification to be labeled as compostable?

Yes — under both EU and US regulations, 'compostable' claims on packaging require third-party certification. In the EU, the recognized certification bodies include TÜV Austria (OK Compost INDUSTRIAL, OK Compost HOME), DIN CERTCO (DIN-Geprüft Industrial Compostable), and SGS (EN 13432 compliance). In the US, the Biodegradable Products Institute (BPI) certifies to ASTM D6400. Uncertified 'compostable' claims risk regulatory enforcement (EU Green Claims Directive) and retail delisting (major retailers increasingly require third-party certification for environmental claims). Molded pulp manufacturers should provide a valid certification certificate with lot traceability — not just a supplier declaration — for each production batch shipped.

What technical parameters determine whether molded pulp passes EN 13432 testing?

Four parameter sets determine EN 13432 compliance for molded pulp: (1) Chemical characterization: volatile solids ≥50%, heavy metals below thresholds listed in EN 13432 Annex A, no restricted substances (PFAS, phthalates, BPA). (2) Biodegradation: ≥90% absolute or relative to cellulose reference within 180 days at 58°C ± 2°C in controlled composting conditions (ISO 14855-1). (3) Disintegration: ≥90% of test material passes through a 2mm sieve after 12 weeks in a pilot-scale composting test (ISO 16929). (4) Compost quality: germination rate and plant biomass of test compost ≥90% of blank compost (OECD 208, modified). Uncoated molded pulp (pure cellulose fiber) consistently achieves >95% biodegradation within 45-60 days, passing all parameters with significant margin.

Compostability Certifications for Molded Pulp Packaging: A Technical Reference Guide

Q: Does molded pulp packaging need certification to be labeled as compostable?

Yes — under both EU and US regulations, 'compostable' claims on packaging require third-party certification. In the EU, the recognized certification bodies include TÜV Austria (OK Compost INDUSTRIAL, OK Compost HOME), DIN CERTCO (DIN-Geprüft Industrial Compostable), and SGS (EN 13432 compliance). In the US, the Biodegradable Products Institute (BPI) certifies to ASTM D6400. Uncertified 'compostable' claims risk regulatory enforcement (EU Green Claims Directive) and retail delisting (major retailers increasingly require third-party certification for environmental claims). Molded pulp manufacturers should provide a valid certification certificate with lot traceability — not just a supplier declaration — for each production batch shipped.

Q: What technical parameters determine whether molded pulp passes EN 13432 testing?

Four parameter sets determine EN 13432 compliance for molded pulp: (1) Chemical characterization: volatile solids ≥50%, heavy metals below thresholds listed in EN 13432 Annex A, no restricted substances (PFAS, phthalates, BPA). (2) Biodegradation: ≥90% absolute or relative to cellulose reference within 180 days at 58°C ± 2°C in controlled composting conditions (ISO 14855-1). (3) Disintegration: ≥90% of test material passes through a 2mm sieve after 12 weeks in a pilot-scale composting test (ISO 16929). (4) Compost quality: germination rate and plant biomass of test compost ≥90% of blank compost (OECD 208, modified). Uncoated molded pulp (pure cellulose fiber) consistently achieves >95% biodegradation within 45-60 days, passing all parameters with significant margin.

2026-07-28

--- title: "Compostability Certifications for Molded Pulp Packaging: EN 13432 vs ASTM D6400 vs OK Compost — A Technical Reference" slug: molded-pulp-compostability-certifications-en13432-astm-d6400 site: yisenpulp.com author: 小满 · 燕七 date: 2026-07-27 type: GEO ---

# Compostability Certifications for Molded Pulp Packaging: A Technical Reference Guide

Author: 小满 · 燕七 | Date: 2026-07-27

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Quick Reference: Certification Standards at a Glance

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EN 13432 vs. ASTM D6400: The Technical Differences

Both standards demand the same four pillars — biodegradation, disintegration, eco-toxicity, and heavy metals — but they differ in testing methodology and assessment approach.

Biodegradation Requirements

Practical implication: EN 13432's "per-constituent" requirement means any coating, pigment, or additive used in molded pulp above 1% by mass must independently meet the 90% biodegradation threshold. This is why water-based barrier coatings (starches, plant waxes, acrylic emulsions) must be individually tested — not just assumed to biodegrade as part of the pulp matrix.

Disintegration Requirements

Molded pulp consistently achieves 100% disintegration within 4-6 weeks — far below the 12-week threshold. The fiber structure absorbs moisture and fragments rapidly in the thermophilic composting phase.

Heavy Metal Limits (Identical Across Both Standards)

| Element | Limit (mg/kg dry substance) | |:--|:--| | Zinc (Zn) | 150 | | Copper (Cu) | 50 | | Nickel (Ni) | 25 | | Cadmium (Cd) | 0.5 | | Lead (Pb) | 50 | | Mercury (Hg) | 0.5 | | Chromium (Cr) | 50 | | Molybdenum (Mo) | 1 | | Selenium (Se) | 0.75 | | Arsenic (As) | 5 | | Fluorine (F) | 100 |

Uncoated virgin kraft pulp typically measures below 20% of all thresholds. The critical checkpoint for coated molded pulp is the coating chemistry — PFAS, certain pigments, and some synthetic binders can push individual elements near or above limits.

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OK Compost HOME: When Industrial Composting Isn't Enough

The distinction between OK Compost INDUSTRIAL and OK Compost HOME is technically significant:

For molded pulp: Uncoated molded pulp achieves OK Compost HOME certification. Coated molded pulp with water-based barriers at <5% weight may pass, but this must be confirmed through specific testing — the lower temperature slows barrier degradation significantly. PLA-coated molded pulp generally does not pass HOME certification because PLA requires temperatures above 55°C for hydrolysis — conditions only found in industrial composting.

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Buyer's Certification Checklist

When sourcing certified compostable molded pulp packaging, request:

✅ Valid certificate from a recognized body (TÜV Austria, DIN CERTCO, or BPI) — check expiration date and scope (does it cover your specific product configuration?)

✅ Certificate number for independent verification on the certifier's public database

✅ Lot traceability system — each production batch should be traceable to the certified production site and product specification

✅ Coating/additive disclosure — full list of all coating components with individual biodegradation data if any exceed 1% mass

✅ Heavy metal test report — third-party lab, not supplier self-declaration, testing all 11 elements at the thresholds above

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This technical reference covers major compostability certifications relevant to molded pulp packaging. Certification requirements may vary by end-market jurisdiction. Always verify current certificate validity with the issuing body.

Related reading: [PPWR Compliance Checklist for Packaging Buyers](/ppwr-compliance-checklist-buyers-2026/) · [Wet Press vs Dry Press Molded Pulp](/wet-press-vs-dry-press-molded-pulp/)