Overview
EN ISO 11997-2:2025 - Paints and varnishes - Determination of resistance to cyclic corrosion conditions - Part 2: Wet (salt fog)/dry/humidity/UV light describes a laboratory test method to assess the resistance of coatings to a defined cycle of salt fog, drying, high humidity and UV exposure. The method uses a specified spray solution and controlled artificial-weathering and cyclic-corrosion cabinets to simulate aggressive outdoor conditions in a reproducible way.
Key topics and technical requirements
- Scope and principle: Defines exposure to a cyclic sequence of wet (salt fog)/dry/humidity/UV light and evaluation of coating degradation by agreed criteria.
- Salt fog solution: Preparation using sodium chloride and ammonium sulfate in water of ISO 3696 grade 1 or 2 with concentrations c(NaCl) = (0.50 ± 0.01) g/L and c[(NH4)2SO4] = (3.50 ± 0.01) g/L; purity limits for salts are specified.
- Apparatus: Specifies use of an artificial-weathering cabinet conforming to ISO 16474-3 fitted with UVA 340 lamps and a cyclic-corrosion cabinet per ISO 11997-1. The default cycle is 4 h light (UV) at 60 °C black-panel temperature followed by 4 h condensation in the dark at 50 °C.
- Test panels and preparation: References ISO 1513 and ISO 1514 for sample preparation and ISO 2808 for film thickness. Scribing, drying/conditioning and sampling procedures are required.
- Evaluation and reporting: Degradation assessments use the ISO 4628 series (blistering, rusting, cracking, flaking, delamination, filiform corrosion). Test report items and examination procedures are defined.
- Flexibility: Annex A provides alternative procedures; parties may agree other cycles or light sources where appropriate.
Practical applications
- Quality control: Routine batch testing to ensure coating performance is maintained.
- Product comparison and R&D: Comparative screening of formulation variants for cyclic corrosion/UV resistance.
- Specification and procurement: Supporting performance claims for industrial maintenance coatings (notably on steel) used in infrastructure, automotive, marine and industrial environments.
- Failure analysis: Reproducing field-like cyclic degradation to investigate causes of coating breakdown.
Who should use this standard
- Coatings manufacturers and formulators
- Independent testing laboratories and certification bodies
- Paint applicators, maintenance engineers and asset owners (steel structures, vehicles, offshore equipment)
- Procurement professionals and standards committees specifying coating performance
Related standards
Keywords: EN ISO 11997-2:2025, cyclic corrosion, salt fog, UV light, paints and varnishes, coating resistance, artificial weathering, UVA 340, test method.
