Overview
ISO 6270-3:2018 - Paints and varnishes - Determination of resistance to humidity - Part 3: Condensation (in-cabinet exposure with heated, bubbling water reservoir) defines standardized conditions and procedures for subjecting coated test specimens to a constant condensation water atmosphere. The document establishes reproducible test atmospheres (supersaturated vapor produced by bubbling compressed air through heated water) and apparatus requirements to produce continuous condensation on coated surfaces. Note: specimen shape/preparation, test duration and final assessment methods are not prescribed by this part.
Key topics and technical requirements
- Principle: Compressed air is bubbled through heated water to introduce saturated vapour into a chamber, creating continuous condensation on specimens; rotation promotes uniform deposition.
- Apparatus components: chamber, heated water reservoir (deionized/distilled water), air supplier and filter, specimen rack (fixed or rotating), temperature control, condensate drip pan and corrosion‑resistant construction.
- Control parameters:
- Typical test temperature: 49 ± 2 °C (alternative 80 ± 2 °C by agreement).
- Relative humidity: >95% (supersaturated conditions).
- Water reservoir level: 205 ± 5 mm.
- Rotating rack speed (if used): 0.33 ± 0.02 r/min.
- Air mass flow: typically about 3 × chamber volume per hour; compressed air must be oil‑free.
- Specimens: default substrate burnished steel per ISO 1514; typical dimensions 75 × 150 mm; coating thickness measured per ISO 2808; condition specimens per ISO 3270.
- Test conduct: mount specimens (use substitutes for empty slots), avoid drips from chamber walls, do not interrupt the prescribed test period.
- Evaluation & reporting: evaluate deterioration using appropriate methods such as ISO 4628; required test report items include product ID, apparatus type, temperature/humidity, coating thickness, drying/ageing conditions, deviations and results.
Practical applications and users
ISO 6270-3:2018 is used for:
- Objective humidity/condensation stress testing of protective coatings and varnishes.
- Comparative laboratory testing for quality control, R&D and product specifications.
- Assessing coating performance relevant to corrosion protection in humid environments.
Typical users:
- Coating manufacturers, R&D laboratories and QC teams
- Automotive, marine, construction and industrial specifiers evaluating humidity resistance
- Test laboratories performing standardized environmental exposure tests
Related standards
- ISO 1514 - Standard panels for testing
- ISO 2808 - Determination of film thickness
- ISO 3270 - Temperatures and humidities for conditioning and testing
- ISO 4618 - Terms and definitions for paints and varnishes
Keywords: ISO 6270-3:2018, paints and varnishes, condensation testing, humidity resistance test, in-cabinet exposure, heated bubbling water reservoir, rotating specimen rack, corrosion protection testing.
Open preview (PDF)Paints and varnishes — Determination of resistance to humidity — Part 3: Condensation (in-cabinet exposure with heated, bubbling water reservoir)