Overview
ISO 22640:2023 - "Rubber - Framework for physical and chemical characterization of tyre and road wear particles (TRWP)" - defines a standardized framework for analysing the physical and chemical properties of tyre and road wear particles (TRWP). Applicable to both laboratory‑generated and environmental TRWP samples, the standard maps existing analytical methods (primarily International Standards, plus selected ASTM and AFNOR methods) to produce comparable, robust data for particle morphology, size distribution, composition, metals and PAHs.
Key topics and technical requirements
- Scope and applicability
- Framework for characterization of TRWP from roadways or generated in the lab.
- Emphasis on published standards for method selection and justification.
- Physical characterization
- Morphology: qualitative assessment by scanning electron microscopy (SEM); quantitative shape metrics (aspect ratio, circularity) via transmission optical microscopy.
- Particle size distribution: combination of transmission optical microscopy and laser diffraction in accordance with ISO 13320 (covers ~0.1 µm to 3 mm, with guidance for out‑of‑range particles).
- Chemical characterization
- General composition: solvent extraction per ISO 1407 followed by thermogravimetry (TGA) per ISO 9924‑3 (NF T46‑047 as an alternative) to quantify polymers, oils/plasticizers, carbon black and mineral fillers.
- Metallic content: guidance references methods such as ASTM D1971 with applicable digestion and spectrometric techniques (AAS, ICP‑OES, ICP‑MS).
- Tyre element content (Si, S, Zn): sample digestion per ISO 14869‑3 (microwave HF/HNO3/HCl) and element determination using ISO 11885 (ICP‑OES).
- PAH content: extraction and quantification methods (e.g., AfPS GS 2019:01 PAK) or total aromaticity assessment via ISO 21461 (NMR) as an alternative.
- Test report requirements
- Mandatory reporting items include sample identification, reference to ISO 22640:2023, test date/time, analyst identity, equipment/conditions, chemicals/reagents, results, anomalies and referenced method details.
Applications and who uses it
- Environmental laboratories and analytical testing facilities performing TRWP monitoring and fate studies.
- Regulatory agencies and environmental consultants assessing sediment/soil and aquatic contamination.
- Tyre manufacturers and researchers studying wear mechanisms, material formulations and ecotoxicity.
- Academics and NGOs investigating microplastics, urban runoff and vehicle non‑exhaust emissions.
ISO 22640 supports consistent data generation for environmental fate, toxicity assessment, regulatory monitoring and product development by aligning TRWP testing to established particle analysis, digestion and spectrometry standards.
Related standards