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  • Shading Coefficients
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    Shading Coefficients

    The total shading coefficient is a measure of the total amount of heat passing through the glazing (known as the total solar heat transmittance) compared with that through a single clear glass. The shading coefficient (SC) is derived by comparing the solar radiant heat transmission properties of any glass with a clear float glass having a total solar heat transmittance of 0.87 (i.e. clear float glass about 4mm thick).

    The shading coefficient (SC) can be separated into long-wave and short-wave components, whose values are derived in exactly the same way, by comparing with the same property of 4mm clear float:

    • The short wavelength shading coefficient (SWSC) is the direct solar heat transmittance divided by 0.87.
    • The long wavelength shading coefficient (LWSC) is the fraction of the absorptance released inwards, again divided by 0.87.

    Spectrum Calculation Program


    Pilkington Spectrum is a Windows-based glass performance model which enables you to quickly and efficiently calculate key properties of insulating glass units without the need to construct and measure them. You can use Pilkington Spectrum to provide the following information:

    • Light and solar properties (transmittance, reflectance, absorptance, g value, etc.).
    • Centre pane Ug-value.
    • Sound insulation values.
    • Ultra violet (uv) transmittance and colour rendering index (Ra).
    • Other properties (e.g. pendulum body impact resistance, fire resistance, resistance to manual attack, etc.).
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