Glass terminology-LT,LR,SC,SHGC,U Value etc.
For architects and designers,energy-saving and green building has become the most important consideration when designing new elegant projects.
To hep you better understanding the architects’ requirement,here’s some glass terminology.
Visible light transmittance
Usually abbreviated as Tv, or LT, is in the visible spectrum (wavelength of 380nm ~ 780nm) range, the percentage of light intensity through the glass. (Visible light transmittance greater, indicating that the more transparent glass. The value of a direct impact on the indoor lighting energy consumption.
Visible light reflectance
Rv or may be abbreviated as RT, is in the visible spectrum (wavelength of 380nm ~ 780nm) range, the glass surface of the percentage of reflected light intensity.
Mainly used to limit reflective glass curtain wall, “light pollution”phenomenon.
Solar direct transmittance
Abbreviated as Tsol, in the solar spectrum (wavelength of 300nm ~ 2500nm) range, through the glass in the ultraviolet, visible and near infrared light percentage of total energy. But does not include the glass absorb the incident sunlight energy directly to the outside world after the energy part of the secondary radiation.
Solar direct reflectance
Abbreviated as Rsol, in the solar spectrum (wavelength of 300nm ~ 2500nm) range, the glass surface reflection of the ultraviolet, visible and near infrared light percentage of total energy.
Total solar energy transmittance
Also called the solar heat gain coefficient (SHGC), the sun factor, g values. Through windows and doors or interior walls component as the heat gain and solar radiation onto a door or wall components of solar radiation on the ratio.
total solar energy transmittance, including solar direct transmittance Tsol and glass and components absorb heat inward after the second radiation. This parameter is the calculation of building energy efficiency an important reference factors, directly affect heating and cooling energy consumption of the indoor.
Abbreviated as SC. Refers to the sun through the windows of the amount of radiation energy and by the same amount of area of 3mm clear glass ratio. SC = g value ÷ 0.87 (or 0.889).
Heat transfer coefficient
Refers to heat transfer in a stable condition, the glass on both sides of the air temperature is 1 degree, the unit of time, 1 square meter of glass by heat transfer to W/m2K or W/m2 ℃, said Imperial units expressed as Btu / hr / ft2 / F, Imperial units U values obtained by multiplying the conversion factor 5.6783 metric U value. U value of the lower heat transfer coefficient, indicating the better thermal insulation properties of glass.
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