Overview
ISO/TS 19392-2:2018 - Paints and varnishes - Coating systems for wind‑turbine rotor blades - Part 2 - specifies a laboratory test method (rotating arm test) for determining the resistance of rotor‑blade coating systems or tapes to rain erosion. The procedure simulates high‑velocity raindrop impacts by accelerating coated test panels through a controlled artificial rain field. Erosion is assessed by visual and microscopic inspection until the composite substrate becomes exposed, enabling pass/fail decisions and comparative ranking of coatings.
Keywords: ISO/TS 19392-2:2018, rain erosion, rotating arm test, rotor blade coatings, wind turbine, coating systems, rain erosion resistance.
Key Topics and Requirements
- Test principle: Coated panels mounted on rotating arms pass through a simulated rain field; droplet impacts progressively remove coating layers.
- Apparatus: Rotating‑arm test rig with rain generator - multiple designs exist; users should note that differing rigs/parameters can yield non‑comparable results.
- Specimens: Typical substrates are glass‑fibre reinforced polymer composites; sample geometry and lay‑up should reflect real blade leading‑edge configuration.
- Sampling & preparation: Follow ISO 15528 (sampling) and ISO 1513 (sample prep). Coatings should be applied as in production; taped specimens require agreed preparation.
- Conditioning: Condition specimens at standard atmosphere (ISO 291, Class 2: 23 ± 2 °C / 50 ± 10 % RH) for at least 7 days prior to testing.
- Calibration: Mandatory for new rigs and parameter changes; calibration according to ASTM G73‑10 using reference materials (e.g., Al, stainless steel, PU, PMMA).
- Test parameters (typical ranges):
- Test medium temperature ≈ 20 ± 3 °C
- Specimen speed at impact area ~ 80–200 m/s (facility‑dependent)
- Droplet mean diameter ~ 1.5–5.5 mm
- Rain rate ~ 10–720 mm/h
- Water flow ~ 1–60 l/min
- Measurements & evaluation: Pre‑ and post‑exposure visual inspection, coating thickness (ISO 2808), roughness, wetting, erosion depth; defect evaluation guided by ISO 4628 series and visual assessment practices (ISO 13076).
- Repetition: Minimum three determinations per coating/tape and test condition.
Applications and Who Uses It
ISO/TS 19392-2 is used by:
- Coating manufacturers developing and qualifying leading‑edge protection systems.
- Wind turbine OEMs and blade manufacturers for supplier evaluation and acceptance testing.
- Independent test laboratories performing comparative erosion testing and certification.
- Materials and R&D engineers for product development, failure analysis, and lifecycle assessment.
Practical uses include quality control, comparative benchmarking of coatings/tapes, supplier contracts, and research into rain/hail erosion mitigation.
Related Standards
Using ISO/TS 19392-2:2018 helps ensure consistent laboratory simulation of rain erosion, supporting more reliable selection and qualification of rotor‑blade coatings for wind energy applications.