Researchers in Singapore have accelerated the weathering of PV retires and investigated their flame spread behavior with different intervals. After 6 weeks they discovered that weathered PV back magazines show 46% faster flame spread than unnecessary. They have also emphasized that current safety standards do not take into account the long -term relegation.
A research group of Nanyang Technological University in Singapore has investigated flame spread behavior on weathered PV and has discovered that they have a considerably faster flame spread than unwanted counterparts.
Two modules available on the market, the group urges the industry to revise “existing safety standards, in particular the IEC 61215 standard”, say that they do not record critical long-term breakdown mechanisms.
“Despite their crucial role as the initial low-exposed layer, backsheet fire performance remain insufficiently characterized, in particular with regard to breakdown exposure to the environment. Current safety standards mainly evaluate entire modules instead of specific components, which may be looking forward to vulnerability points,” said the academics. “We have selected backsheets for this study based on their position as the primary interface between external fire sources and the PV module.”
The group has tested two commercial PVbacksheethigen, both with polyethylene leftalate (PET) as their most important component. Example A had a TPE configuration, which stood for a structure of Tedlar/PET/Eva, while Monster B had a KPK configuration, with a structure of Kynar/Pet/Kynar. They were tested after exposure to a transmission device with four intervals: unwanted, 3 weeks, 4.5 weeks and 6 weeks of exposure.
The accelerated weathering process followed a modified protocol based on the IEC 61215 Standard Test. It included an exposure of UVA-340A lamps at 1 W/m2 at 65 ° C for 8 hours, followed by condensing humidity at 50 ° C for 4 hours in the dark, with a water spray duration of 0.15 hours. The research group has developed a time-to-marker (TTM) technology for the assessment of the flame spread.
“Sample preparation included marking three points with intervals of 15 mm to quantify flame forecast. To combat the shrinking effects of the thin polymer plate under direct flame exposure, we have rolled the samples in a conical shape with an overlap of 1 mm, protected with the help of metal staples. “The conical geometry is necessary because thin polymer films (0.2-0.5 mm) undergo rapid shrinkage and distortion in a flat configuration, preventing reproducible measurements. Despite the geometric difference with field installations, TTM intrinsic material properties independent of the monstergeometry.”
To explain the morphology and mechanical properties, the Scanning -Electron Microscopy group (SEM) and draft tests has performed. According to the results, a ramp or the release of TIO2 particles was observed, which resulted in crack formation. Moreover, the tensile strength in both samples decreased, with Monster B demolished faster.
Chemical breakdown was analyzed using weakened total reflection Fourier-Transform Infrared Spectroscopy (ATR-FTIR). The hydrolysis of PET, the formation of new chemical groups and the loss of hydrogen bridges were identified as the most important factors that led to breakdown.
“Vlamtests revealed significant differences between weathered and non-desired samples. Unpacked Monster A showed a flame spread speed of 2.8 mm/s, which lasted 9 seconds to reach the 3rd marker, the longest time registered between all samples. The 6-week destroyed afared avonded a-vault A. Seconds for the unwanted sample, “they found the observed increase in flame spread speeds, in particular the 46% reduction in TTM for sample B after six weeks of weathering, underlines the critical impact of the environment on fire safety.”
Furthermore, Differential Scancalorimetry (DSC) showed that Monster A has a slight reduction in the melting point from 253.59 ° C to 253.43 ° C after six weeks of exposure. Monster B, showed two different melting points at around 120 ° C and 250 ° C in its different layers. Thermogravimetric analysis (TGA) revealed the start of the decomposition for Monster A at 422.48 C and Monster B at 434.92 C.
The findings of the investigation were published in “Research into the fire dynamics of mounted PV dyeing effects and material changes‘It appeared in it is.
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