Q. What glass is used on the glass canopy?

Answer

A glass canopy is used to allow the integration of daylighting. Therefore, the obvious choice of glass would be a clear glass. But glasses also come in many different types and it is important to know how they differ from each other, based on certain characteristics. Three important parameters to consider when selecting glass are VLT (Visual Light Transmittance), SHGC (Solar Heat gain Coefficient) and U-Value. VLT is the percentage of visual light allowed from the incident surface of glass to the inside of it. SHGC discusses the amount of solar heat transmitted from the glass. SHGC of 1 means that all the heat from outside is allowed inside, while that of 0 means that none of the outside solar heat is permitted inside. U-Value describes the rate of heat flow either as conduction, convection or even radiation. For glass canopy, a clear toughened laminated glass with high VLT, and Low SHGC and U-value must be selected. Typically, 70% or more VLT, 0.1 or below SHGC as well as U Value of 0.3 and below would be ideal for glass used in glass canopy.