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Buildings may earn a rating of between one and four globes. This is an online system; a building's information is verified by a Green Globes-approved and trained licensed engineer or architect. To qualify for a rating, roofing materials must have a solar reflectance of at least 0.65 and thermal emittance of at least 0.90.
While directional-hemispherical reflectance factor is calculated for a single angle of incidence (i.e., for a given position of the Sun), albedo is the directional integration of reflectance over all solar angles in a given period. The temporal resolution may range from seconds (as obtained from flux measurements) to daily, monthly, or annual ...
Inherently cool roofs: Roof membranes made of white or light colored material are inherently reflective and achieve some of the highest reflectance and emittance measurements of which roofing materials are capable. A roof made of thermoplastic white vinyl, for example, can reflect 80% or more of the sun's rays and emit at least 70% of the solar ...
Roofing material is the outermost layer on the roof of a building, sometimes self-supporting, but generally supported by an underlying structure. A building's roofing material provides shelter from the natural elements. The outer layer of a roof shows great variation dependent upon availability of material, and the nature of the supporting ...
Jones's glossmeter used a geometric configuration of 45°/0°/45° whereby the surface was illuminated at 45° and two incident reflective angles measured and compared at 0° (diffuse reflectance) and 45° (diffuse plus specular reflectance). Jones was the first to emphasize the importance of using goniophotometric measurements in studies of gloss.
In architecture, light reflectance value (LRV), is a measure of visible and usable light that is reflected from a surface when illuminated by a light source. [1] The measurement is most commonly used by design professionals, such as architectural color consultants , architects , environmental graphic designers and interior designers .
As it is an opaque material, the remaining 10 percent must be reflected. Conversely, a low-e material such as aluminum foil has a thermal emissivity/absorptance value of 0.03 and as an opaque material, the thermal reflectance value must be 1.0 - 0.03 =0.97, meaning it reflects 97 percent of radiant thermal energy. Low-emissivity building ...
Radiant barrier materials must have low emissivity (usually 0.1 or less) at the wavelengths at which they are expected to function. For typical building materials, the wavelengths are in the mid- and long-infrared spectrum, in the range of 3-15 micrometres. [citation needed] Radiant barriers may or may not exhibit high visual reflectivity.