Overview
IEC TS 62788-7-2:2017 - Measurement procedures for materials used in photovoltaic modules - Part 7-2 provides standardized accelerated weathering tests and artificial exposure procedures to characterize the weatherability of polymeric materials used in photovoltaic (PV) modules. The Technical Specification focuses on polymeric backsheets and encapsulants, defining steady-state simulated solar irradiance, temperature and humidity exposures to support component characterization, research and product development. Cyclic stresses (thermal and wet/dry cycles) are intentionally excluded for future work.
Key topics
- Artificial weathering exposures: A suite of steady-state test methods that simulate long-term outdoor aging without cyclic stresses.
- Two main light-source methods:
- Method A: Filtered xenon arc with daylight filters (spectral match to solar).
- Method B: Fluorescent UVA-340 lamps to emulate UV-rich solar components.
- Controlled parameters: spectral irradiance, irradiance levels, material temperature, and relative humidity (RH), plus recommended length of exposure and dosage considerations.
- Specimen constructions: Guidance for test specimens including single films/sheets, design-specific laminates, and single components tested behind representative filters.
- Reporting requirements: Standardized reporting of exposure conditions and results for reproducibility and comparison.
- Informative annexes:
- Annex A: Characterization of fielded module conditions (climate data, module temperature, backside irradiance).
- Annex B: Rationale, development of methods, and recommendations for use (irradiance selection, dosage comparisons).
Applications
- Qualification and development of PV module component materials (backsheets, encapsulants).
- Accelerated material screening in R&D to predict outdoor durability and optimize polymer formulations.
- Reference procedures for standards bodies and certification programs to align component tests with module-level qualification.
- Test-lab procedures for reproducible artificial weathering that correlate with field exposure benchmarks.
Who should use this standard
- PV module and materials manufacturers evaluating polymeric backsheets or encapsulants.
- Independent testing laboratories performing accelerated weathering and durability testing.
- R&D teams in polymer science and PV product development.
- Standards committees and product qualification programs referencing artificial exposure methods.
Related standards
- IEC 60904-3 (reference spectral irradiance for PV measurements)
- IEC 61730-1 (PV module safety – construction requirements)
- IEC TS 61836 (PV terms and definitions)
- IEC 62788-1-4 (encapsulant optical transmittance measurement)
Keywords: IEC TS 62788-7-2, accelerated weathering tests, artificial weathering, polymeric materials, photovoltaic modules, backsheets, encapsulants, xenon arc, UVA-340, irradiance, weatherability.