Overview
EN ISO 2812-2:2018 titled "Paints and varnishes - Determination of resistance to liquids - Part 2: Water immersion method" is an internationally recognized European standard developed by CEN in collaboration with ISO Technical Committee ISO/TC 35. This standard specifies a reliable laboratory method for assessing the resistance of both single-layer and multi-layer coating systems to water exposure through partial or full immersion testing. The standard provides a systematic approach to measure how coatings withstand water-induced degradation and, where applicable, evaluates any resultant damage to the substrate beneath the coating.
This updated 2018 version supersedes the 2007 edition with key technical revisions, improving the accuracy and applicability of water immersion testing in paints and varnishes quality assurance. It is widely adopted across Europe and aligned with ISO's international framework, ensuring consistency and comparability in coating performance testing.
Key Topics
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Scope and Purpose
Defines a standardized method for evaluating water resistance of coatings by immersing coated test panels in water and monitoring the effects based on predefined criteria.
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Test Panels and Sample Preparation
Specifies use of polished steel panels sized typically 150 mm x 100 mm x 0.7–1.0 mm, coated on one or both sides depending on testing agreements. Panels are dried, conditioned, and may be subjected to artificial damage like scribes or scrapes for corrosion impact studies.
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Apparatus Requirements
Mandates use of inert materials for any device in contact with water, with apparatus including a thermostatically controlled tank, circulation and aeration systems, and supports for test panels at an angle of 0° to 20° to the vertical.
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Testing Procedure
Panels can be partially (three-quarters length) or fully immersed in water maintained at 40 ± 2 °C, with water quality meeting ISO 3696 grade 3 specifications. Continuous water circulation and aeration ensure uniform test conditions.
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Evaluation Criteria
Visual and subjective assessments of coating changes such as blistering, discolouration, or substrate degradation are carried out during interim and final inspections to determine resistance level.
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Relevant Definitions and Normative References
Incorporates terms defined in ISO 4618 and references related ISO standards covering paint sampling, film thickness measurement (ISO 2808), scribing methods (ISO 17872), and cathodic disbonding resistance testing (ISO 15711).
Applications
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Quality Control in Paint and Coating Manufacturing
Used by manufacturers to verify coating formulations meet water resistance requirements, ensuring product durability.
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Construction and Infrastructure Coatings
Applicable for assessing protective paints used on steel and metal substrates exposed to moisture or submerged conditions such as bridges, pipelines, and marine structures.
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Automotive and Transportation Industry
Useful for evaluating water resistance of automotive paints and protective varnishes, contributing to corrosion protection and appearance retention.
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Research and Development
Enables R&D teams to compare coating systems objectively and optimize formulations for enhanced water resistance.
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Regulatory Compliance and Certification
Supports compliance with industry standards requiring demonstration of liquid resistance, aiding product registration and certification processes.
Related Standards
- ISO 1513 – Examination and preparation of test samples for paints and varnishes.
- ISO 1514 – Standard panels for testing paints and varnishes.
- ISO 2808 – Measuring the dry film thickness of coatings.
- ISO 3696 – Specification for purified water used in analytical laboratories.
- ISO 4618 – Terms and definitions related to paints and varnishes.
- ISO 4628-2 – Evaluation of coating degradation, specifically blistering assessment.
- ISO 15711 – Resistance to cathodic disbonding of coatings in sea water.
- ISO 17872 – Guidelines for scribe mark introduction for coating corrosion tests.
By following EN ISO 2812-2:2018, industry professionals can reliably determine the water resistance performance of coatings, thus enhancing product longevity and maintaining structural integrity in aqueous environments. This method is an essential part of coating evaluation, helping users make informed decisions about coating selection for specific environmental conditions.
