Insulated Glass, often called double glazing, is a combination of two or more panes of glass spaced apart with a spacer bar and hermetically sealed with a primary and secondary sealant to form a single unit with one or more air spaces in between. IG units improve the thermal performance, thus significantly reducing heating and air-conditioning costs. IG units also reduce interior condensation in cold climates, and increase comfort near windows, thus maximizing the usable interior space.
By combining Low-E coatings, tinted glasses, reflective coatings, silk-screened patterns, laminated glass products and more, a wide variety of insulating glass configurations are available to satisfy a wide range of performance and aesthetic requirements. IG units can be fabricated to meet state energy codes, sound control requirements, seismic requirements, impact resistance, bullet resistance, and hurricane and blast resistance requirements. IG units can be designed to reduce heat loss and solar heat gain entering the building, with a minimal reduction of visible light transmittance.
An IGU consists of at least two panes (or lites) of glass. Though IG units typically use monolithic glass, other types of coated and laminated glasses may be used depending on the application to enhance the performance of the unit.
Frame, or the spacer bar, is the material used to separate the two glass lites in an IGU. Usually made of aluminium and filled with desiccant, it holds the unit together, provides thickness and mechanical resistance, and plays a key role in ensuring optimum performance of the unit.
Frames are of two types - ones joined with corner keys, and bent frames. In the first type, the spacer material is cut to the specific size and desiccant is filled. Then the four sides are assembled together using corner keys. As the frame created in this process has four joints, the heat loss is more. To address this, the frame or the spacer bar is bent at 90 degree angles and the frame is assembled with only one joint - this is referred to as a bent frame.