ISO 11997-1:2017

Overview

ISO 11997-1:2017 - Paints and varnishes - Determination of resistance to cyclic corrosion conditions - Part 1: Wet (salt fog)/dry/humid defines a laboratory method to evaluate the corrosion resistance of coatings by exposing coated test panels to a controlled cycle of salt fog (wet)/dry/humid conditions. The standard specifies preparation of salt solutions, test apparatus, panel preparation, exposure cycles (Annexes A–D) and evaluation/ reporting criteria to compare coating performance under reproducible, accelerated cyclic corrosion conditions.

Key topics and technical requirements

• Scope and principle: Method for assessing resistance of coatings to one of four defined cyclic wet/dry/humid schedules using specified salt solutions.
• Test cycles: Four normative cycles (Annex A–D) are provided - Cycle A (JASO-based), Cycle B (VDA-based), Cycle C (UK-developed) and Cycle D (JIS-based) - each representing different field-relevant conditions for industrial and automotive coatings.
• Salt fog test solution: Use analytical-grade salts and laboratory water (ISO 3696). Limits on impurities are specified (e.g., total heavy metals Cu/Ni/Pb < 0.005 %, NaI ≤ 0.1 %, total impurities ≤ 0.5 %). pH adjustment and control procedures are included.
• Apparatus and cabinet design: Requirements for corrosion-resistant spray cabinets, salt deposition control, roof design to prevent drip, heating/airflow to achieve specified temperatures and humidity profiles, and filtration of solution to prevent nozzle blockage. Annex E provides factors for cabinet design and construction.
• Test panels and sampling: Material, dimensions, coating application, drying/conditioning, film thickness, and scribe preparation are specified. Evaluation uses agreed criteria and normative references for degradation assessment.
• Examination and reporting: Assessment procedures, precision, and required test report content are defined to ensure reproducibility and comparability.

Practical applications - who uses ISO 11997-1:2017

• Coatings manufacturers and formulators for R&D and product development.
• Quality assurance and control laboratories for batch verification.
• Automotive, marine, and industrial maintenance sectors for prequalification and comparative performance testing.
• Independent test laboratories offering corrosion resistance certification. The method is particularly useful for comparing cyclic salt spray resistance across different coating systems and for evaluating performance trends under simulated aggressive outdoor environments.

Related standards

• ISO 11997-2 (cyclic corrosion including UV exposure)
• ISO 4628 series (assessment of degradation: blistering, rusting, delamination, filiform corrosion)
• ISO 9227 (salt spray testing guidance; harmonization noted)
• ISO 3696 (water quality for laboratory use), ISO 1513/1514, ISO 2808 (sample/panel preparation and film thickness)

Keywords: ISO 11997-1:2017, cyclic corrosion, salt fog, wet/dry/humid, coatings testing, corrosion resistance, paint testing, cyclic salt spray.