Overview
ISO 2812-2:2018 - "Paints and varnishes - Determination of resistance to liquids - Part 2: Water immersion method" specifies a laboratory method to evaluate the water resistance of single- or multi-layer coatings by partial or full immersion. The procedure assesses effects of water on the coating and, where required, the damage to the substrate (e.g., corrosion or loss of adhesion). This third edition (2018) updates several test tolerances and procedural details from earlier editions.
Key topics and technical requirements
- Test principle: Immerse coated test panels in water and evaluate deterioration according to pre‑agreed criteria (usually visual/subjective).
- Test pieces: Polished steel panels (≈150 mm × 100 mm; 0.7–1.0 mm thick) prepared per ISO 1514; coating application, drying and conditioning specified by the user.
- Immersion modes: Partial immersion (three‑quarters length) or full immersion (water level ≥50 mm above top of panel).
- Test conditions:
- Water temperature: 40 ± 2 °C by default (unless otherwise agreed).
- Water quality: grade 3 per ISO 3696 (or other waters for specific end‑uses, e.g., seawater).
- Circulation/aeration or stirring recommended to maintain homogeneous conditions.
- Apparatus: Tank with cover, heater and thermostatic control; inert materials for water contact. Example tank size provided (700 × 400 × 400 mm).
- Panel support & placement: Panels set at 0°–20° to vertical, spaced ≥30 mm from each other, tank walls and bottom; positions normally rearranged periodically (≤3 days).
- Sampling and pretests: Follow ISO 15528 and ISO 1513 for sampling and pretesting.
- Damage simulation: Optionally apply a scribe (ISO 17872) or artificial holiday (ISO 15711).
- Evaluation:
- Interim and final inspections for blistering and deterioration using ISO 4628‑2; adhesion changes may be measured with ISO 4624.
- Tests carried out in duplicate unless otherwise agreed.
- Reporting: Detailed test report requirements (coating ID, panel details, immersion mode, duration, temperature, results, anomalies, tester name, date).
Applications and users
ISO 2812-2 is used for:
- Quality control and acceptance testing of paints and varnishes.
- Formulation development and comparative water resistance screening.
- Corrosion engineers and specifiers assessing coating performance for marine, industrial or architectural applications.
- Test laboratories, manufacturers, and certification bodies requiring standardized water immersion testing and documented results.
Related standards
Standards referenced within ISO 2812-2 include:
Keywords: ISO 2812-2, water immersion method, paints and varnishes, resistance to liquids, water resistance testing, coating durability, test panels, coating adhesion.
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