Reflective Glass is an ordinary float glass with a metallic coating to reduce solar heat. This special metallic coating also produces a mirror effect, preventing the subject from seeing through the glass. It is mainly used in façades. Reflective glasses are mainly manufactured by two different process such as Production Pyrolitic (On-Line) and Vacuum (magnetron) Process (off-line). In the day time people from outside cannot see inside the building and at night things can been seen inside the building.
Special coatings can be applied to a float glass surface to make it reflective to short wave radiation from the sun and/or long wave radiation from heat inside or outside the building. These coatings are known by a variety of terms, but there are two main types:
- Pyrolytic Coatings
A coating applied on line at high temperature during the float manufacturing process. Also known as on line or hard coatings.
- Sputtered Coatings
A coating applied off line in special equipment, also known as off line, vacuum, or soft coatings.
Traditional reflective glass has a mirror-like appearance and reflects and absorbs a major proportion of the sun’s direct short wave solar radiation. The degree of reflectivity is dependent on the type of coating and the orientation of the glass. The use of reflective glass is more popular in commercial glazing as it provides superior solar control performance to clear or tinted glass products, and thus improves the energy efficiency of the building.
Low Emissivity (Low E) coatings are traditionally clear and are designed to reflect long wave radiation. They are available in both pyrolytic and sputtered coatings and the performance varies. Some modern reflective glass products have Low E coatings to reflect long wave radiation as well as the sun’s short wave radiation.
Today’s reflective glasses have evolved and now feature varying levels of reflectivity that create a wide range of aesthetics. The mirror box effect is definitely a thing of the past! Below are some key benefits to designing buildings with reflective glass:
- Color: Tinted, reflective architectural glasses offer better harmonization with spandrels, metal panels, extrusions and other building materials. This color enriched glass transmits generous levels of visible light and offers color neutrality, which also enhances the tint of the glass substrate underneath the reflective coating. Today, reflective glasses can also include low-e coatings.
- Visibility: Reflective glass also has a special metallic coating that makes it possible to see out, while preventing people from seeing in, in order to preserve privacy during the day. In addition, reflective glass makes it possible to hide computer wires, vents, fans, HVAC components and other building mechanicals.
- Glare Control: Reflective glass also impacts visible light transmittance (VLT). Reflective glass allows just the right amount of natural light into a building, while at the same time reduces glare and the need for window blinds and other interior shading devices. In addition, reflective solar control glass reflects a portion of incoming solar radiation, which limits heat penetration into the building and can potentially lower HVAC usage.
- Exterior Appearance: Reflective glass provides a bold, crisp exterior appearance, along with a dynamic building surface that changes to reflect the color of the sky, the passing of clouds and the different times of day.