Emissivity and Solar Reflectance Measurement Services

The Surface Optics 410 Family

The 410-SOLAR forms part of the 410 range of portable reflectometers and emissometers from Surface Optics Corporation that are designed for reflectance, solar absorbance and thermal emissivity measurements in the visible to far infrared range. These modular devices feature interchangeable measurement heads and a common command module and generate data of comparable quality to much larger laboratory instruments.

410-SOLAR Head for Reflectance & Solar Absorptance Measurements

The Surface Optics 410-SOLAR provides measurements of reflectance (total hemispheric, diffuse and specular) averaged within 7 wavebands from 330 to 2500nm. Measurements are made in the following bands: 335-380nm; 400-540nm; 480-600nm; 590-720nm; 700-1100nm; 1000-1700nm; and 1700-2500nm. The 410-SOLAR employs a tungsten lamp with integrating sphere for measurements in a 20°/H geometry (directional illumination at 20° to surface normal/hemispheric collection).

The 410-SOLAR is compliant with ASTM E903 (Solar Absorptance, Reflectance, and Transmittance of Materials Using Integrating Spheres) and C1549 (Determination of Solar Reflectance Near Ambient Temperature Using a Portable Solar Reflectometer). Solar absorptance is computed for AM 0 (extra-terrestrial) and AM 1.5 (terrestrial).

ET-100 Head for Reflectance & Thermal Emissivity Measurements

As well as the aforementioned 410-SOLAR measurement head, Pro-Lite also has available the ET-100 head that provides for measurements of reflectance and thermal emissivity in the 1.5-21μm waveband. Measurements of total hemispheric reflectance are made at 20° and 60° incidence and averaged within 6 wavebands between 1.5 to 21μm. Measurements are made in the following bands: 1.5-2μm; 2-3μm; 3-4μm;4-5μm; 5-10μm; and 10-21μm. The ET-100 employs a thermal filament source maintained at 1000°C within an integrating sphere. The integration of these values with the Planck function gives the directional thermal emissivity, from which the hemispheric thermal emissivity is computed. The ET-100 is compliant with ASTM E408 (Total Normal Emittance of Surfaces Using Inspection-Meter Techniques).

Emissivity is that property of a material that determines its effectiveness at emitting thermal radiation, defined as the ratio of the quantity of thermal radiation emitted from a surface compared to the perfect black body radiator maintained at the same temperature, given by the Stefan-Boltzman law. The measurement of emissivity is important for the calibration of pyranometers and thermal cameras which make non-contact temperature measurements.

Combined 410-SOLAR & ET-100 Measurement Capabilities

Combining the results from the 410-SOLAR and the ET-100 measurement heads provides for measurements of reflectance, solar absorptance and thermal emissivity. From this data set, the solar reflectance index (SRI) is computed in accordance with ASTM E1980 (Standard Practice for Calculating Solar Reflectance Index of Horizontal and Low-Sloped Opaque Surface).

Ergonomic Design

The lightweight pistol-grip design is modelled on a battery operated power tool. It is highly portable and allows single-handed use. Simply hold the sample port against the surface to be tested and press the trigger to take the measurement. View results immediately on the touch-screen display. Measurements can be taken on curved surfaces without special jigs or fixtures. The 410 Series measures the reflectance of flat, convex and concave surfaces (max. 150mm & 300mm radius, respectively) with a measurement spot of 6.4mm diameter.