Our newsletter OTM Insights Issue 5 was sent to our customer on 27 Jul 2020. We are sharing some technical insights of accuracy of glass optical & thermal property test results in the newsletter. Click the image to read the full newsletter.
Our lab is now able to perform thermal conductivity test of soil samples, according to ASTM D5334 (with instrument manufacturer’s instruction). We use transient hot wire method to perform the test, with a needle-type measurement probe shown in the photo below.
Our newsletter OTM Insights Issue 4 was sent to our customer on 27 Apr 2020. We are sharing some technical insights of optical & thermal property test of glasses from existing buildings in the newsletter. Click the image to read the full newsletter.
Our newsletter OTM Insights Issue 3 was sent to our customer on 03 Feb 2020. We are sharing some technical insights of partially fritted glazing optical & thermal property testing procedures in the newsletter. Click the image below to read the full newsletter.
Color and gloss are commonly used quality check quantities by material suppliers and construction companies, whereas daylight reflectance are relatively new to the industry. This article aims to explain the relationship between the three quantities.
Daylight reflectance and color
The total and diffuse daylight reflectance is directly related to color. Materials with light color are with high total or diffuse daylight reflectance; materials with dark color are with low total or diffuse daylight reflectance. Our eyes cannot quantify daylight reflectance, but they can assess daylight reflectance qualitatively.
Most color instruments with integrating sphere geometry can measure color in the SCI (specular component included) mode or the SCE (specular component excluded) mode. Color measured in the SCI mode is equivalent to the total daylight reflectance; color measured in the SCE mode is equivalent to the diffuse daylight reflectance.
The closest color scale is Yxy scale. Of course, due to various technical constraints, color measurement instruments cannot accurately determine daylight reflectance, but the results are sufficient for internal use.
Daylight reflectance and gloss
The specular daylight reflectance is directly related to gloss. Materials with high gloss are with high specular daylight reflectance; materials with low gloss are with low specular daylight reflectance. Our eye can qualitatively assess if a surface is with high gloss or with low gloss.
Gloss meters can measure material gloss level. However, the relationship between gloss meter readings and specular daylight reflectance is qualitative. It is not possible to quantitatively coorelate them.
Notes to applications
For projects where low specular daylight reflectance is required, materials with low gloss level are preferred.
For projects where low total daylight reflectance is required, materials with dark color are preferred.