ISO 2812-4:2017

Overview

ISO 2812-4:2017 - Paints and varnishes: Determination of resistance to liquids - Part 4: Spotting methods - specifies laboratory procedures to evaluate how individual-layer or multi-layer coating systems resist exposure to liquids and paste‑like substances. The standard defines spotting test procedures that reveal coating damage and, where needed, allow assessment of substrate attack. Typical test substances include fuels, automotive fluids, laboratory chemicals (with CAS numbers listed), and biological deposits (e.g., simulated bird droppings).

Key topics and requirements

• Test principle: Apply a defined quantity of test substance to a coated test panel (spotting) and assess effects against agreed criteria.
• Apparatus: Common lab equipment including a pipette (~0.1 ml droplets), 50 ml burette, and 60 mm Petri dishes.
• Test panels: Use standard panels (≈150 × 100 mm, 0.7–1.0 mm thick) prepared per ISO 1514 and coated with the product/system under test. Measure dry film thickness using ISO 2808 methods.
• Conditioning and conditions: Condition panels for at least 16 h at (23 ± 2) °C and (50 ± 5) % RH (ISO 3270); perform tests at (23 ± 2) °C.
• Spotting methods:
  • Method A (horizontal): Apply droplets or ~0.5 cm of viscous/paste-like substances, cover with Petri dishes; perform duplicate tests. Maintain at least 12 mm clearance from panel edges.
  • Method B (inclined): Place panel at 30° and apply liquid drops from a burette at 1–2 s intervals over 10 min so the liquid flows into a collecting vessel.
• Evaluation: After test duration, remove residues (wipe with dry cotton wool; rinse aqueous residues; use a non‑attacking solvent for others). Assess blistering per ISO 4628-2 and visible alterations per ISO 4628-1; reassess after 24 h. Additional tests (cross‑cut, hardness) or substrate examination may be performed.
• Reporting: Include identification of coating, panel details, method used, test substances and duration, temperature, results, operator name, deviations, anomalies and test date. Note: precision data (repeatability r, reproducibility R) are not specified.

Applications and who uses it

ISO 2812-4 is used for:

• Quality control and production testing by paint and varnish manufacturers.
• Automotive and transport coating validation (resistance to fuels, oils, washer fluid, bird droppings).
• Independent test laboratories and R&D teams assessing new formulations or multi-layer systems.
• Specification writers and procurement to define liquid resistance requirements in technical contracts.

Keywords: ISO 2812-4, spotting methods, paint testing, coating resistance to liquids, liquid resistance test, paints and varnishes standard.

Related standards

• ISO 1513, ISO 1514, ISO 2808, ISO 3270, ISO 4628-1, ISO 4628-2, ISO 4618, ISO 15528 (referenced for sample prep, panels, thickness, conditioning and evaluation).