Overview
EN ISO 15711:2004 (ISO 15711:2003) - "Paints and varnishes - Determination of resistance to cathodic disbonding of coatings exposed to sea water" - defines laboratory test methods to evaluate how organic coatings on metallic substrates resist cathodic disbonding when exposed to sea water. Adopted by CEN, the standard targets coatings used on ships and marine structures and explicitly excludes assessment for land‑based structures.
Key topics and requirements
- Two standardized test methods:
- Method A (impressed current): potentiostatic control of the test substrate electrode potential (preferred). A cathodic protection circuit maintains the electrode at –1 050 ± 5 mV vs saturated calomel; galvanostatic control may be used if a potentiostat is unavailable.
- Method B (sacrificial anode): sacrificial metal anodes electrically attached to coated panels to produce a practical shipboard cathodic protection condition.
- Test specimen layout and exposure:
- Coating applied to metallic panels; artificial, defined defects introduced to simulate discontinuities.
- For Method B, four panels (two protected, two unprotected controls) are typical; immersion for six months is specified for the comparative assessment.
- Test environment and media:
- Artificial sea water formulation is specified (e.g., NaCl 23.0 g/l, MgCl2·6H2O 9.8 g/l, Na2SO4·10H2O 8.9 g/l, CaCl2 1.2 g/l) unless natural sea water is agreed.
- Test tanks and aeration/circulation, temperature control, and reference electrodes (calomel or Ag/AgCl) are described.
- Evaluation and reporting:
- Assessment criteria reference related ISO test methods (e.g., ISO 4628‑2 for blistering, ISO 4624 for pull‑off adhesion).
- The document includes requirements for apparatus, sampling, conditioning, expression of results and supplementary information (Annex A).
Applications and who uses it
- Practical uses:
- Qualification and comparison of marine coatings, anti‑corrosion paints and varnishes under cathodic protection conditions.
- Research and development of coating formulations with improved resistance to cathodic disbondment.
- Pre‑qualification testing for coatings intended for ship hulls, offshore platforms, and other sea‑water‑exposed metallic structures.
- Typical users:
- Coating manufacturers, R&D labs, naval architects, shipyards, corrosion engineers, testing laboratories and certification bodies.
Related standards
Commonly used alongside or referenced by EN ISO 15711:
EN ISO 15711:2004 is essential when assessing coating performance in marine cathodic protection contexts - use it to ensure reproducible, comparable test data for coatings deployed in sea water environments.