Overview
ISO/TS 19392-5:2023 defines a test method for measuring the UV and visible (UV/VIS) spectral transmittance of coatings used on wind‑turbine rotor blades. The specification covers single and multilayer coatings, permitting testing of free coating films or coatings applied to a UV‑transparent quartz substrate. Measurements are carried out across the spectral range 280 nm to 700 nm, enabling calculation of transmittance for UV, VIS and combined UV+VIS bands to assess UV‑protective performance.
Key topics and technical requirements
- Spectral range and output: Measurement of spectral transmittance τ(λ) from 280–700 nm, reported in defined wavelength increments (instrument dependent).
- Instrumentation: Use of a UV/VIS spectrophotometer equipped with a radiation source (e.g., deuterium or halogen), limiting aperture, integrating sphere, and spectroradiometer/diffraction detector.
- Instrument performance: Requirements include stray‑light suppression, dark‑current correction, higher‑order wavelength correction, wavelength calibration and a resolution/step capability around 2 nm.
- Sample preparation: Coatings may be tested as free films or on quartz substrates; typical dry film thicknesses referenced and thickness measurement per ISO 2808.
- Environmental conditioning: Specimens conditioned per ISO 3270 or supplier instructions before measurement.
- Checks and validation: Use of a long‑pass (cut‑on) filter to verify spectrophotometer performance (50% cut‑on between about 320–360 nm and very low transmittance in the absorption region).
- Data and calculations: Spectral transmittance recorded across the band and integrated to give band transmittance values (UV, VIS, UV+VIS); software to compute τ(λ) is required.
- Precision and reporting: Test precision, number of specimens (minimum three), and required test report details are specified.
Applications and users
- Coating manufacturers and formulators assessing UV protective coatings for rotor blades.
- Wind‑turbine OEMs and blade manufacturers specifying or verifying coating performance to protect composite substrates from UV/VIS degradation.
- Independent test laboratories and certification bodies performing quality control, R&D evaluation, and comparative performance testing.
- Material scientists and durability engineers using spectral transmittance data to predict weathering, color change and substrate protection.
Related standards
- ISO 2808 - Determination of film thickness
- ISO 3270 - Temperatures and humidities for conditioning and testing
- ISO 4618 - Paints and varnishes vocabulary
ISO/TS 19392-5:2023 provides a reproducible, instrument‑based method to quantify how well blade coatings block damaging UV and short‑wavelength visible light - a critical input for improving blade lifetime and reducing UV‑driven failure modes.
Open preview (PDF)Paints and varnishes — Coating systems for wind-turbine rotor blades — Part 5: Measurement of transmittance properties of UV protective coatings