Overview
ISO 16620-2:2019 - Plastics - Biobased content - Part 2 specifies an internationally accepted calculation method for determining the biobased carbon content of plastics, monomers, polymer resins, additives and plastic materials. The method is based on measurement of radiocarbon (14C) and converts measured 14C content into the fraction of carbon that is of recent biogenic origin. Knowing biobased carbon content is valuable for environmental assessment, product labeling and life‑cycle analysis.
Key topics and requirements
- Scope: Applicable to plastic products, polymer resins, monomers, additives and modifiers containing biobased and/or fossil constituents.
- Radiocarbon principle: Uses 14C as a tracer - biogenic carbon contains modern 14C whereas fossil carbon contains negligible 14C.
- Sample preparation and sampling: Samples must be representative; complete combustion and conversion of carbon to CO2 (or suitable target) is required for measurement.
- Measurement methods: Three validated options are specified:
- Method A - Liquid scintillation counting (LSC): Low cost, normal lab equipment; typical duration 4–12 h; relative standard deviation ~2–5%.
- Method B - Beta‑ionization (BI): Low background gas counting; duration 8–24 h; relative standard deviation ~0.2–5%.
- Method C - Accelerator mass spectrometry (AMS): Direct 14C measurement; fast (10–30 min), high precision (0.2–2%) but higher instrument cost.
- Carbon metrics: Standard requires determination of total carbon (TC) and/or total organic carbon (TOC) and defines calculations for:
- Biobased carbon by mass (xB,TC),
- Biobased fraction of total carbon (xB by TC),
- Biobased fraction of total organic carbon (xB by TOC).
- Corrections & reference values: REF values and correction factors are used to convert measured percent modern carbon (pMC) to 100% biobased carbon equivalents (Table references included in the standard).
- Reporting: Test report content and normative annexes (sample conversion, LSC, BI, AMS methods) are specified.
Applications and users
- Manufacturers and material suppliers for product claims, biobased labeling and sourcing transparency.
- Independent testing laboratories and accreditation bodies performing 14C analysis and issuing certification.
- Environmental consultants and life‑cycle assessment (LCA) practitioners quantifying biobased content in carbon accounting.
- Regulators and procurement teams defining biobased product criteria and sustainability targets.
- R&D and polymer scientists validating new bio‑based resins, additives or blends.
Related standards
- ISO 16620-1: General principles for biobased content measurements.
- ASTM D6866: Comparable methods and terminology for biobased/biogenic carbon measurement (useful cross‑reference).
ISO 16620-2:2019 is a practical, methodical standard for verifying the biogenic fraction of plastics using radiocarbon techniques, enabling consistent, defensible assessments of biobased content for sustainability reporting and compliance.
