EN 13523-27:2017

Overview

EN 13523-27:2017 defines a reproducible test method (the Cataplasm or humid poultice test) to evaluate the resistance of organic coil coatings on metallic substrates under conditions of extreme humidity. The method reproduces an enclosed, aggressive humid environment (acidic, alkaline or neutral) and measures coating performance by inspecting blistering, rusting and other degradation.

This standard is part of the EN 13523 series for coil coated metals and is intended for manufacturers, test laboratories and quality teams responsible for coating durability and corrosion resistance verification.

Key Topics

• Principle: Specimens are enclosed in a thermally sealed plastic bag with moist absorbent cotton and a defined volume of test solution, then exposed at elevated temperature to accelerate degradation.

• Specimen preparation: Typically four specimens per environment (e.g. acid, alkaline, neutral), normally 75 mm × 150 mm, flat and clean. Edges are sheared with burrs away from the test surface unless otherwise specified.

• Materials & apparatus:

  • Purified absorbent cotton-wool single layer ≈ (22.5 ± 2.5) g, cut to ~250 × 650 mm
  • Thermally sealable plastic bag (e.g. polyethylene) at least 0.22 mm thick
  • Specific test solutions: deionised water (conductivity < 0.5 mS/m) for neutral; standard buffer pH 4 for acidic; standard buffer pH 9 for alkaline. Composition of buffers shall be agreed and reported.
  • Oven capable of maintaining (70 ± 3) °C

• Exposure & duration: Bagged specimens are placed horizontally in the oven at (70 ± 3) °C for an agreed test duration (commonly 7 or 14 days). Bags remain sealed during exposure.

• Evaluation: After cooling, specimens are wiped and assessed without delay. Overall surface and edge defects are classified using EN ISO 4628 series methods (blistering, rusting, flaking, filiform corrosion).

Applications

• Quality control and batch verification for coil-coated steel and aluminium
• Comparative assessment of coating formulations and surface treatments
• Corrosion risk assessment for applications subject to prolonged humidity or contact with wet packaging
• Input to product specifications, supplier agreements and compliance reporting

Practical benefits: standardized, repeatable assessment; accelerated ageing under controlled acidic/alkaline/neutral conditions; clear pass/fail criteria referenced to EN ISO 4628 evaluation metrics.

Related Standards

• EN 13523-0 - General introduction to the coil coated metals test series
• EN ISO 4628-2, -3, -5, -10 - Evaluation of coating degradation (blistering, rusting, flaking, filiform corrosion)
• EN 1396, EN 10169 - Delivery specifications for coil coated aluminium and steel
• EN ISO 3696 - Deionised water quality for analytical use

For test reports, EN 13523-27 requires identification of the product, reference to EN 13523-27, applied test conditions (including buffer composition), test duration, results (Clause 8) and any deviations from the procedure.