Overview
ISO 6270-1:2017 defines a standardized method to determine the resistance of paint films, paint systems and related products to continuous condensation. The procedure simulates severe humid conditions where condensation forms on the coating surface and provides an indication of likely performance under such exposure. The method applies to coatings on both porous substrates (e.g., wood, plaster, plasterboard) and non‑porous substrates (e.g., metal).
Note: this part does not cover specimen shape and preparation from liquid paints, test duration, or the final assessment criteria, which are to be specified in coating or product specifications or agreed between interested parties.
Key Topics
- Principle: Expose coated specimens to continuous condensation and inspect for deterioration such as blistering, staining, softening, wrinkling and embrittlement, and for substrate attack.
- Apparatus: Constructed from chemically resistant materials; essentially an electrically heated water bath with a cover formed by test or blanking specimens. A climatic chamber example is provided to promote uniform condensation on the test surface.
- Operating conditions:
- Preferred air temperature 25 mm below specimens: (38 ± 2) °C. Alternative recommended temperatures: (49 ± 2) °C or (60 ± 2) °C if 38 °C is too low.
- Specimen angle: preferred (60 ± 5)° to horizontal (acceptable range 15°–75°).
- Water level: maintained automatically or by regular manual addition; follow equipment manufacturer guidance on water quality to avoid calcification.
- Specimens and run:
- Typical specimen sizes: 75 × 150 mm or 100 × 150 mm.
- Tests are carried out in duplicate unless otherwise specified; include a control specimen of known durability where practical.
- Continuous operation is required, with only short daily interruptions for inspection, re‑arrangement or water checks.
- Inspection and evaluation: Periodic and final examinations are made without allowing specimens to dry fully. Evaluation is by agreed criteria (for example, ISO 4628 parts or a contractual procedure).
Applications
ISO 6270-1 is used by manufacturers, test laboratories and specifiers to:
- Assess coating resistance to continuous condensation and humid atmospheres.
- Reveal failure modes (blistering, staining, softening, wrinkling, embrittlement).
- Evaluate potential substrate deterioration beneath coatings.
- Support product development, quality control and comparative performance testing when combined with agreed evaluation criteria.
Related Standards
- ISO 3270 - Temperatures and humidities for conditioning and testing (referenced for standard atmospheres).
- ISO 4618 - Terms and definitions for paints and varnishes.
- ISO 4628 (all parts) - Typical benchmark for evaluation of coating degradation; evaluation methods are applied by agreement.
Reporting: The test report shall identify the product and specimens, reference ISO 6270-1, record test temperature, specimen angle, test duration and interruptions, inspection timing, removal method (if substrate examined), individual results, deviations and anomalies, and dates of testing.
Keywords: ISO 6270-1, condensation test, paint films, coating resistance, humidity resistance, blistering, substrate deterioration, climatic chamber.
Open preview (PDF)Paints and varnishes — Determination of resistance to humidity — Part 1: Condensation (single-sided exposure)