ISO 6452:2021

Overview

ISO 6452:2021 specifies a standardized test method to determine the fogging characteristics of rubber- or plastics-coated fabrics used as trim materials in motor-vehicle interiors. The method measures condensable volatile constituents that deposit on a cooled glass plate during controlled heating. Results are reported as a fogging value (F)-a gloss reduction measured on the glass-and, optionally, as the mass of condensable constituents (G) collected on aluminium foil. The procedure applies to finished trim materials and to raw fluid, pasty, powdered or solid feedstocks used to make them, and can be run in an oil bath or air chamber (air was added as a thermal transfer fluid in this 2021 edition).

Key topics and technical requirements

• Test principle: Heat a test piece/portion in a thermostatically controlled bath or chamber; volatile components condense on a cooled glass plate or aluminium foil disc.
• Fogging value (F): Calculated as the percentage ratio of gloss with condensate to gloss without condensate; gloss measured with a 60° gloss meter per ISO 2813.
• Mass measurement (G): Gravimetric determination using aluminium foil discs (0.03 mm thickness, Ø ~103 mm) and a balance with 0.01 mg divisions.
• Apparatus and controls: Bath/chamber stable to ±0.5 °C up to 130 °C; cooling plates maintain ~21 °C mean water temperature; specified beaker, sealing ring, filter paper and spacers ensure reproducibility.
• Materials and references: Thermal transfer fluid may be a modified polyhydric alcohol or air; reference liquid diisodecyl phthalate (DIDP) is used for calibration/verification.
• Limitations: The optical gloss method can under-report when condensate has very low surface tension (forms transparent film) or when heavy oily films form - in these cases the gravimetric method is preferred.
• Updates: 2021 edition adds air as a suitable thermal transfer medium and includes Annex B comparing air-chamber vs oil-bath outcomes.

Applications and users

• Who uses it: automotive OEMs, interior-trim suppliers, materials and quality control laboratories, regulatory/assessment bodies and R&D teams developing coatings, foams and laminates for vehicle interiors.
• Practical uses:
  • Evaluate potential for windshield or glass surface fogging by trim materials.
  • Screen formulations for low-fogging performance before vehicle integration.
  • Support supplier specifications, quality acceptance, and comparative product testing.
  • Provide data for material selection to reduce interior deposit-related visibility or aesthetic issues.

Related standards

• ISO 2813 - referenced for gloss measurement at 60° (used to calculate the fogging value).
• Gravimetric test methods (noted in ISO 6452 as preferred when optical limitations occur) - consult product-specific or laboratory protocols for mass-only determinations.

Keywords: ISO 6452, fogging characteristics, automotive interior trim, rubber- or plastics-coated fabrics, fogging test, gloss meter, condensable constituents, DIDP, thermostatically controlled bath.