Understanding Glass Types and Their Properties
When it comes to design innovations and creating design trends, glass has always been one of the most sought-after materials for facades and fenestrations. Today, glass is widely used in buildings owing to its versatility, making it one of the top choices for architects and designers. It not only adds to the aesthetics and visual appeal of a building but also plays an important role in the overall performance of the building.
Although the primary function of glass is to allow optimum daylight into interior spaces, the correct choice can also impact the overall energy consumption of a building through thermal heat transfer, solar heat gain, visible transmittance and air leakage. It also accounts for factors like safety, acoustics, structural strength, etc. making it a desirable building material.
Choosing the right glazing for the projects can be quite daunting as there are various materials, styles, features and physical properties to choose from. We often do not know the correct choice for our requirements as there is a lack of research. Hence, an understanding of the various kinds of glass available in the market is quite important.
Tempered Glass
Tempered or “toughened” glass is one that has been thermally and chemically treated to increase its strength. In addition, it can “chunk” or crumble into small granular pieces rather than knife-like shards. Although it doesn’t hold up under sustained physical attack, it is less likely to develop cuts if it breaks.
Tempered glass is reasonably priced, easy to install, stronger than standard float glass and mostly harmless if broken. But we must also note that it is not a true security glass as it can be broken easily. It must also be ordered to size and takes a long delivery time. Tempered glass is most commonly used in vehicles, glass doors and construction in earthquake-prone areas.
Laminated Glass
Laminated glass is created by sandwiching a durable plastic interlayer (usually polyvinyl butyral or PVB) between two panes of strengthened glass. The glass and PVB are chemically bonded to one another during the manufacturing process, making it incredibly difficult to break. In case the glazing is struck, it breaks within the frame but is held in place by the PVB. Hence, it also doubles as a safety glass. Another important aspect of laminated glass is that additional layers of glass and PVB can be added during the manufacturing process.
Laminated glass also has limited bomb resistance, bullet resistance, and is very strong against manual forced entries and “smash-and-grab” theft but they can be quite expensive. On the downside, the glass is strong but tends to crack easily. Laminated glass is mostly used in aquariums, schools, banks, retail buildings, vehicles and earthquake-prone areas.
Insulated Glass
Insulated Glass combines two or more glass panes that are spaced apart and sealed with a sealant to appear as a single unit. Also known as double glazing, Insulated Glass Units (IGUs) are designed to reduce heat loss and solar heat gain entering the building, while reducing visible light transmittance. Hence, it improves thermal performance and reduces energy consumption. It can also be fabricated to meet sound control requirements, seismic requirements, bullet resistance, hurricane resistance, blast resistance, impact resistance and state energy codes. By combining laminated glass products, tinted glass, low-E coatings, reflective coatings, silk-screened patterns, etc., a wide variety of insulating glass configurations can be made available to meet diverse aesthetic and performance needs.
IGUs can be used in larger glazed areas without increasing energy consumption while ensuring transparency as they help in reducing the incidence of condensation on the warm airside. For example, they are used in soft drink chillers in retail stores, airports, etc.
IGUs are also highly effective in reducing sound transmission as the air inside them prevents the resonance from passing through. Hence, buildings near airports, railway stations, and main roads are constructed using IG to prevent noise from entering the building.
