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Measurement of high solar reflectance paint for roofs using the model UH5700 spectrophotometer
Thermal barrier coatings have the same coloring as ordinary paint. However, they reflect the infrared light that is the source of heat from sunlight, and control the propagation of radiant heat to internal structures. JIS K 5675 specifies a test method for quantitative assessment of the reflectance properties of high solar reflectance paint for roofs against sunlight. Here we introduce an example of calculating the solar reflectance of paint using the model UH5700 spectrophotometer.
The model UH5700 spectrophotometer was equipped with a 60mm
integrating sphere accessory attachment to measure the reflection spectrum of
three types of samples of applied coating in accordance with JIS K 5675(Figure
1)
In JIS K 5675, the reflectance spectrum is multiplied by weighting factors and the weighted average is taken to calculate the solar reflectance. In addition, the solar reflectance (near-infrared) and separately calculated brightness L were used to assess samples in accordance with Table 1.
A near-infrared solar reflectance of 84.8% and L value of
94.7 were obtained for coating B. Since the reflectance value 84.8% is higher
than the criterion of 80.0% specified in the bottom row of Table 1, the sample
was judged to be conforming.
Solar reflectance and assessment results can be calculated automatically by using the optional UV Solutions Plus software.
Hitachi UH5700 UV-VIS-NIR
For more information on Hitachi UV/Vis-NIR, please visit Hitachi High-Tech Science website
https://www.hitachi-hightech.com/global/products/science/ai/