Overview
EN ISO 6270-1:2018 / ISO 6270-1:2017 - “Paints and varnishes - Determination of resistance to humidity - Part 1: Condensation (single-sided exposure)” specifies a standardized method to assess the resistance of paint films and coating systems to continuous condensation. Adopted by CEN as EN ISO 6270-1:2018, the standard is used to reproduce severe humidity conditions where condensation forms on one face of the coated specimen, giving an indication of coating performance under wet, humid service environments.
Key topics and technical requirements
- Scope: Applicable to coatings on both porous (wood, plaster, plasterboard) and non‑porous (metal) substrates; intended to reveal coating failures and substrate deterioration caused by continuous condensation.
- Test principle: Single-sided exposure of a coated specimen to continuous condensation; effects are evaluated against agreed criteria.
- Apparatus: Electrically heated water bath/climatic chamber constructed from chemically resistant materials to generate condensation on the inner face of specimens.
- Specimen orientation: Preferred angle (60 ± 5)° to horizontal (acceptable range 15°–75°) to permit drainage and avoid cross-contamination between specimens.
- Temperature control: Air space temperature beneath specimens generally (38 ± 2) °C; alternatives of (49 ± 2) °C or (60 ± 2) °C permitted if 38 °C is too low.
- Water and installation: Water level control recommended; ordinary tap water may cause calcification - follow equipment manufacturer guidance. Apparatus to be installed in a non‑corrosive, draft‑free room at approx. (23 ± 5) °C and ≤75 % RH.
- Specimen size and repetition: Typical specimen sizes 75 × 150 mm or 100 × 150 mm; tests normally carried out in duplicate.
- Observations: The method can reveal blistering, staining, softening, wrinkling, embrittlement and substrate damage.
- Limitations: The standard does not prescribe specimen shape/preparation, exact test duration or final assessment criteria - these are to be specified in coating/product specifications or agreed between parties. Results are indicative and not a direct lifetime prediction.
Applications and users
- Who uses it: Coating manufacturers, quality control laboratories, material engineers, R&D teams, and specifiers creating performance requirements for paints and varnishes.
- Practical uses:
- Type-approval and quality control of protective and decorative coatings.
- Comparative testing of formulations intended for humid or condensation-prone environments (e.g., basements, industrial interiors, marine enclosures).
- Identifying failure modes (blistering, staining, etc.) during product development or pre-delivery inspection.
Related standards
- ISO 4628 series - for rating coating degradation (evaluation may be performed by agreed procedure).
- ISO 3270 - conditioning temperatures and humidities for paints and varnishes.
Keywords: EN ISO 6270-1:2018, ISO 6270-1:2017, resistance to humidity, condensation test, paints and varnishes, single-sided exposure, coating testing, climatic chamber, condensation resistance.