November 2025: New Standards for Paint and Coating Corrosion

November 2025: New Standards for Paint and Coating Corrosion Resistance

In November 2025, the global paint and coatings industry marked a significant milestone with the publication of two harmonized standards: EN ISO 11997-2:2025 and ISO 11997-2:2025. These new editions provide a robust, reproducible test methodology for assessing the resistance of paints and varnishes to complex weathering cycles—including wet (salt fog), dry, humid, and UV light exposure. The adoption of these standards assures higher reliability in predicting coating performance, vital for sectors ranging from construction and transportation to heavy industry. This article offers a comprehensive deep-dive into the standards’ technical content, key changes, and practical impacts for businesses and quality professionals across the paint and colour industries.

Overview / Introduction

The paint and coatings sector plays an integral role in protecting surfaces from corrosion, maintaining aesthetics, and extending the service life of underlying materials. Ensuring the quality and durability of these coatings is complex, as real-world environmental exposure involves a dynamic interplay of moisture, salt, heat, humidity, and sunlight. Standards are the foundation for consistent testing, regulatory compliance, lifecycle prediction, and global trade.

With the November 2025 publication of EN ISO 11997-2:2025 and ISO 11997-2:2025, industry professionals now have up-to-date, internationally aligned methods for evaluating how coatings endure the full spectrum of harsh cyclic environmental conditions. By reading this article, you’ll:

Understand the core elements and scope of the new standards
Learn about key testing methodologies and performance criteria
Explore the compliance, quality, and commercial impacts of these specifications
Get actionable insights for implementation and risk mitigation

Detailed Standards Coverage

EN ISO 11997-2:2025 - Resistance to Cyclic Corrosion (Wet/Salt Fog, Dry, Humid, UV)

Paints and varnishes — Determination of resistance to cyclic corrosion conditions — Part 2: Wet (salt fog)/dry/humid/UV light (ISO 11997-2:2025)

This European-adopted international standard defines a laboratory method for determining the resistance of paint and varnish coatings to complex, cyclic environmental stresses. By simulating realistic cycles of wetting (via salt fog), drying, humidity, and ultraviolet light exposure, it evaluates how coatings respond to the type of fluctuating conditions they experience outdoors or in aggressive service environments.

What the standard covers:

Test cycles that alternate between wet (using a defined saline solution), dry, humid, and UV light periods
Scope designed primarily for industrial maintenance coatings on steel, but applicable to a range of substrates
Methods for preparing and conditioning test panels, including material selection, coating application, and scribing procedures

Key requirements and specifications:

Strict protocols for test panel preparation (material, coating application, film thickness measurement)
Defined apparatus and environmental chamber configurations
Use of reference solutions, including preparation and purity
Assessment of defect types such as blistering, rusting, cracking, flaking, chalking, delamination, and filiform corrosion based on referenced ISO evaluation standards
Mandatory documentation and reporting of test sequences, conditions, and results

Who needs to comply:

Paint and coatings manufacturers supplying to industries where resistance to corrosion and weathering is essential (e.g., construction, infrastructure, transportation)
Independent test laboratories and quality assurance teams
OEMs and asset owners specifying coating systems for severe service conditions

Implementation and changes from previous versions:

Expanded terms and definitions for clarity
Updates to fluorescent UV lamp designation for laboratory consistency
Modernized normative references and cross-compatibility with other ISO test methods

Key highlights:

Harmonized European and international methodology, enabling cross-border specification
Comprehensive assessment of both chemical (corrosive) and physical (UV, humidity) durability
Actionable criteria for both product development and regulatory testing

Access the full standard: View EN ISO 11997-2:2025 on iTeh Standards

ISO 11997-2:2025 - Cyclic Corrosion Resistance Testing for Paints and Varnishes

Paints and varnishes — Determination of resistance to cyclic corrosion conditions — Part 2: Wet (salt fog)/dry/humid/UV light

The latest third edition of ISO 11997-2, published in November 2025, provides a globally recognized protocol for reproducible laboratory testing of paint and varnish coatings under simulated outdoor conditions. The standard addresses the need for consistent, realistic corrosion testing beyond traditional static salt spray methods.

Scope and methodology:

Simulates alternating environmental conditions, closely mimicking actual field exposure
Focuses on reproducible, controlled variables using programmable laboratory chambers
Enables statistically reliable comparison of multiple coatings or formulations

Key test procedures:

Preparation of standardized test panels (material, dimension, surface treatment)
Precise scribing/defect introduction methods
Conditioning cycles with strict control of humidity, temperature, salt fog concentration, and UV intensity
Defined assessment schedules and test durations
Detailed procedures for visual and quantitative evaluation using referenced ISO methods

Target users:

Global manufacturers aiming for compliance in regulated or export markets
Laboratories conducting type approval or ongoing quality surveillance
Asset owners and project specifiers demanding documented durability

Notable updates and technical advancements:

New clause 3: Expanded terms and definitions, improving clarity for international users
Updated requirements for UV light source selection and calibration
Revised normative references linking to latest ISO test procedures for coating evaluation

Key highlights:

International harmonization with European requirements
Improved reproducibility and comparability for accelerated weathering and corrosion resistance
Practical guidance for complete test documentation and transparency

Access the full standard: View ISO 11997-2:2025 on iTeh Standards

Industry Impact & Compliance

Implementing EN ISO 11997-2:2025 and ISO 11997-2:2025 will profoundly benefit stakeholders in the paint and coating value chain:

Manufacturers must align internal and customer product qualifications with the new, more rigorous testing regime, ensuring coatings withstand the range of challenges encountered in real environments.
Quality managers and compliance officers are equipped to benchmark against up-to-date, harmonized criteria, supporting both regulatory and contractual requirements.
Specifiers and procurement specialists can confidently require coatings proven to perform in cyclic exposures, reducing lifecycle risk and warranty claims.

Compliance considerations and timelines:

Transition period: Organizations should review product claims and test reports to ensure conformity with the November 2025 updates, replacing outdated protocols wherever possible.
Documentation: Full traceability and detailed reporting, as required by both standards, support legal and commercial defensibility.
Third-party certification: Adoption may be a prerequisite for certain markets or supply chain partners, particularly in construction, infrastructure, and automotive/transport sectors.

Benefits:

Enhanced reliability and durability predictions for coatings
Lower risk of premature failures, callbacks, or litigation
Streamlined international trade and supply chain interoperability

Risks of non-compliance:

Potential product rejections or recalls due to inadequate weathering/corrosion testing
Loss of reputation and reduced market access
Increased costs from warranty claims or remedial works

Technical Insights

Common technical requirements

Use of standardized panels for comparative testing (as per ISO 1514)
Accurate film thickness determination using methodologies from ISO 2808
Consistent test chamber control for humidity, temperature, and UV exposure parameters
Strict recipe for salt fog solution, using laboratory-grade water and chemicals
Visual and quantitative defect classification employing ISO 4628 series (blistering, rusting, cracking, flaking, chalking, delamination, filiform corrosion)

Implementation best practices

Validate chambers and calibration of environmental parameters
Train personnel on scribing, coating application, and panel evaluation to minimize operator variability
Store and handle panels with care pre- and post-testing
Maintain detailed records for traceability, including any deviations or supplementary cycles
Consider using Annex A (alternative test procedures) where project-specific requirements differ

Testing and certification

Regular participation in inter-laboratory comparisons can confirm laboratory proficiency
Certification to ISO/IEC 17025 for laboratories enhances credibility
Engage with third-party or customer audits as required by project or contract

Conclusion / Next Steps

The November 2025 release of EN ISO 11997-2:2025 and ISO 11997-2:2025 marks a new era for the paint and coatings industry, raising the bar for durability assurance through more realistic, reproducible cyclic corrosion testing. Organizations across the value chain—manufacturers, project specifiers, asset owners, and testing laboratories—should act now to:

Review and update internal quality programs and procurement specifications
Schedule training and equipment calibration to meet new test requirements
Work with supply chain partners to ensure shared understanding and consistent application

By adopting these standards, businesses can deliver products that thrive in demanding environments, minimize risks, and maintain a leading edge in quality and compliance.

Stay ahead: Access all the latest paint and colour industry standards on iTeh Standards