Overview
CEN ISO/TS 19392-5:2024 (identical to ISO/TS 19392-5:2023) specifies a laboratory test method to measure the spectral transmittance of UV‑protective coatings used on wind‑turbine rotor blades. The method covers the wavelength range 280 nm to 700 nm, enabling separate and combined evaluation of UV (280–400 nm) and visible (VIS, 400–700 nm) transmittance for single or multilayer coating films. It applies to free coating films or coatings applied onto a UV‑transparent quartz substrate.
Key topics and requirements
- Measurement range: Spectral transmittance from 280–700 nm; results can be integrated to obtain UV, VIS, and combined transmittance values.
- Specimens: Single and multilayer coatings; free films or films on quartz substrate.
- Apparatus: UV/VIS spectrophotometer equipped with a radiation source, limiting aperture, integrating sphere and spectroradiometer (diffraction element + detector).
- Sample preparation: Film applicator for coating films, substrate preparation, and film thickness measurement (see ISO 2808 referenced).
- Procedure essentials:
- Record incident and transmitted spectral radiant flux to compute spectral transmittance (τ(λ) = Φt(λ)/Φm(λ)).
- Wavelength scanning recorded continuously (typical step sizes referenced in the specification, e.g. 2–10 nm).
- Check spectrophotometer performance using a long‑pass filter specification and routine checks (normative verification).
- Report calculation method and measurement conditions following the test procedure and reporting requirements.
- Normative references: ISO 2808 (film thickness), ISO 3270 (conditioning), ISO 4618 (vocabulary).
- Precision and reporting: The technical specification includes precision guidance and required test report information.
Applications and practical value
- Evaluate the UV shielding performance of rotor‑blade coatings and coating systems to reduce UV‑induced degradation of glass‑fibre‑reinforced polymer (GFRP) and other blade substrates.
- Support formulation optimization for pigments and UV absorbers to balance durability and optical/colour effects (visible transmittance).
- Provide quantitative input for service‑life assessments, quality control, and acceptance testing of coating batches and prototypes.
- Useful in R&D, accelerated weathering correlation studies, and failure analysis where UV transmittance is a factor.
Who should use this standard
- Coating formulators and manufacturers for wind‑turbine blade coatings
- Independent testing and certification laboratories
- Wind‑turbine OEMs and blade manufacturers (quality control/specification)
- Materials scientists and research organizations studying UV protection and durability
Related standards
- ISO/TS 19392 series (other parts covering rotor blade coating tests)
- ISO 2808 - Determination of film thickness
- ISO 3270 - Conditioning for paints and varnishes
- ISO 4618 - Paints and varnishes vocabulary
Keywords: UV protective coatings, spectral transmittance, UV/VIS spectrophotometer, wind turbine rotor blades, ISO/TS 19392-5, CEN ISO/TS 19392-5:2024.
