Glass is one of the most widely used building materials in architecture, design, and construction. With its unique structural properties, the material can be modified to produce different types of glass in construction.
Glass is manufactured with different physical properties depending on what it will be used for. Several types of glass in construction vary based on safety, thermal performance, climate, and the visual appearance of the buildings. This post will explain the myriad of glass types so you can make an informed decision about what best suits your building needs.
Base Glass – Tempered/Toughened Glass – Heat Strengthened Glass – Laminated Glass – Glass with Ceramic Frit – Low Iron Glass – Body Tinted Glass – Insulated Glass
Base glass consists of annealed float glass and ornamental glass. Float glass is the most basic glazing available internationally, making up to 90% of the base glass.
In the float glass production process, a hot steady layer of molten glass is discharged from a furnace into a huge shallow bath of molten tin. The glass floats and cools on the metal tin and expands to produce a flat surface. Rollers are laid across the glass to stretch and create a thinner glass surface.
Float glass has a maximum dimension of 6.0X3.2mm. The typical breaking strength of annealed float glass is 45N/mm2. Its standard thickness varies between 4,5,6,8,10,12,15,19 mm.
The float glass process produces high-quality structural glass for construction purposes.
727 West Madison Project
Tempered glass is about 2.5 times stronger than standard glass of the same thickness in terms of physical or thermal shock. It is typically used for safety and strength. The glass is heated to a uniform temperature and instantly cooled to strengthen the glass. This makes the inner core of the glass stay fluid longer than the outer surface layer, which allows an equivalent amount of tensile prestress in the core and compressive prestress in the surface layer to be formed. The compressive prestress on the surface is preventing existing microcracks from growing thus making tempered glass stronger than normal glass. The common maximum dimension is 4.0 x 2.4m. The glass thickness is typically 4,5,6,8,10,12,15, or 19mm.
Tempered glass has a typical breaking strength of 120 N/mm2. When tempered glass breaks, it shatters into several non-cutting and fine pieces, avoiding the risk of injury.
Tempered glass is used commercially in structural glass applications where wind, snow, thermal or seismic loads are a threat. This type of glass is used for escalator side panels, balusters, handrails, and fire-resistant doors where strong support is needed. Likewise, it is also used in airport viewing areas.
Sea-Tac International Airport Project
Heat-strengthened glass is about 1.5 times stronger than float glass. It is heat treated in a similar way to tempered glass. However, the cooling process is less rapid compared to tempered glass. The typical thickness of this structural glass comes in 6,8,10, and 12 mm, and its common maximum dimension is 4.0 x 2.4m.
With a typical breaking strength of about 70 N/mm2, heat-strengthened glass has a breaking pattern with large pieces, which is favorable for some laminated glass applications where the post-breakage strength matters.
Heat-strengthened glass is used for structural glass applications in buildings where extra strength is needed to resist wind, snow, thermal and seismic loads. However, heat strengthened glass is not rated as safety glass, unless it is part of a laminated glass unit.
Laminated glass comprises two or more sheets of glass bonded together by interlayers of polyvinyl butyral (PVB) or ionoplast materials. Multiple layers of glass make even stronger glass panels. The excess of glass lites enhances the unit failure safety. The standard PVB thickness is 0.38, 0.76, and 1.52 mm. Their typical maximum dimension is 3.6 X 2.4 m.
Johns Hopkins University: Gilman Hall Project
Ceramic frit is an enamel pattern on the glass surface. It comes in standard colors of the RAL system. The glass can be printed with common print patterns such as dots, holes, and stripes.
In order to apply the frit material to the glass surface, a porous polyester fabric screen (or silkscreen) is stretched on an aluminum frame. Sections of the screen are coated with a non-permeable material to create a stencil negative to the image being produced. This means the open spaces on the screen will develop the frit pattern on the glass surface. Following the frit application, the enamel gets burned in a furnace.
The ceramic frit pattern on the glass surface appears like a screen, acting as a partial or complete cover for privacy or hiding the background. Fritted glass is used for architectural glass walls, glass doors, partitions, stair rails, conference areas, and curtain walls.
Low iron glass is a special float glass composed of raw materials cleaned of iron oxide which causes the greenish tint of regular clear float glass. The standard thickness falls between 6,8,10, and 12mm.
Low iron glass is used in façades and skylights, balustrades, glass floors, and all other applications, where the greenish tint of clear glass is not desirable. Moreover, structural glass fins are often made of low iron glass.
Body tinted glass is float glass formed from unique raw materials that create different colors of the glass. The typical dimension is 3.2 X 2.4 m, and the standard thickness ranges between 6,8,10,12 mm.
This glass reduces the transmitted solar radiation by absorption, thus reducing heat penetration into buildings and helping regulate the building’s temperature as well as limiting energy use. Body tinted glass adds aesthetics to the building with varying colors for stunning visual effects. This glass is typically used in combination with clear or low iron glass in offices, large buildings, and commercial spaces. It is excellent for facades, storefronts, interior design, and skylights.
Insulated glass units (IGU) have a lower thermal transmittance due to the enclosed interspace volume filled with air or argon. The U-value measures the thermal transmittance through the glass. The typical U-value for an air-filled IGU without any coating is about 3.0 W/m2*K.
Insulated glass is produced by sandwiching hollow aluminum or stainless spacer frames between two glass lites. The thickness of the spacer defines the interspace between the two lites. Butyl is used as the primary seal material between the spacer frame and the glass surfaces. Additionally, a secondary seal (silicone) encloses the spacer frame and bonds the glass edges together.
The IGU offers excellent thermal and sound insulation properties. Insulated glass units are used in residential buildings, hotels, colleges, hospitals, and offices. Moreover, it is used for buildings with high heating or cooling needs like airport cooling towers.
UNLV Hotel College Academic Building Project
The thermal transmittance of IGUs can be lowered further using low-emittance (low-E) surface coatings which are microscopically thin, virtually invisible metal or metallic oxide layers. The glass acts like a one-way mirror to the interior space. It reflects most of the radiant heat coming from the interior side but transmits light from the exterior side. The typical U-value for an
air-filled IGU with low E coating is 1.6 – 1.9 W/m2*K. At the same time, the typical U-value for an argon-filled IGU with low E coating is 1.1 – 1.5 W/m2*K.
The solar performance of IGUs can be improved using special solar control low-E surface coatings which act like a one-way mirror to the exterior space by reflecting most of the ultraviolet and infrared light but allowing visible light to pass. The solar heat gain coefficient measures the amount of solar energy transmitted through the IGU.
This type of glass is used in buildings to minimize heat transfer into homes, especially in warm climatic areas.
As evidenced by the production processes listed above, there are different types of architectural glass with varying properties that provide excellent performance and aesthetic appeal for architectural spaces.
Learn more about our architectural glazing systems here, or contact the Novum Structures team today!
Glasxperts
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Feb 22, 2017
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A few decades ago, travelling by an aeroplane was considered a luxury. The ability to travel to places via flight was for the privileged few. Cut to the present and you find several people travelling by aeroplane because it’s the fastest and most convenient way to reach a destination. With the rise in number of passengers for a flight, airports are constantly abuzz with thousands of footsteps crossing their floors day in and day out.
With the passage of time, airports have also undergone a complete makeover with emphasis on grandeur, elegance, glamour, and futuristic elements that leaves you awestruck at times. A key factor in creating breath-taking design and aesthetics is the use of glass in airports. Glass is a highly versatile material that can be adopted for various aspects like security, acoustic comfort, energy efficiency, lighting, décor, and ultra-comfort. Certainly, there is more than meets the eye when it comes to glass solutions.
Here’s how advanced glass solutions reinvent modern airports.
Insulated Glass
Insulated glass is an elementary solution that offers solar protection, thermal insulation, and effective energy management. The implementation of Insulated Glass helps regulate the temperature within keeping the interiors cool while letting natural light in thus keeping the area lit yet comfortable. They can be implemented as energy efficient glass windows that afford beautiful views to the travellers. It makes for an aesthetic delight when combined with tinted glass, patterned glass, laminated glass, and etched glass.
Heat Reflective Glass
Implementing heat reflective glass helps in cutting down heat build-up within the airport premises while optimizing light transmission thereby keeping the area pleasant and bright. As this solution reduces heat considerably, it saves energy consumption too. There is lower requirement for air conditioners and artificial lighting as the heat reflective glass ensures a comfortable atmosphere. This glass solution best works as energy efficient glass windows.
LOW-e COATED GLASS
This is an incredibly energy efficient glass solution for airports. Low-e coated glass is perfect for implementing for terminals and facades. This glass solution is a glass, coated with a film that regulates the entrance of sunlight. A low-e coated glass realizes high light transmission, lowers energy consumption, and ensures a direct view to the outdoors. For travellers, a view of the external spaces is a delight to the mind. The low-e coated glass also helps to keep the terminals and facades bright with natural sunlight while keeping the temperature cool thus providing a wholesome environment to travellers. The beauty of Low-e coated glass is that it can be incorporated with a range of decorative glass that enhance the interior décor of an airport.
Solar Control Glass
Airports cover a large area and possess several terminals, lounges, shops, and outlets. With a glass façade, one would imagine the tremendous amount of sunlight that would enter and heat the interiors. Not so with solar control glass. The heat of the sun can be kept at bay by implementing solar control glass over a large area of the airport. This energy efficient glass, not just reflects but also filters the sun’s rays to keep the interiors bright (without hurting the eyes) but adequately cool. This also leads to a reduction in the use of air conditioning thereby saving energy consumption. It is a versatile cost-effective solution which can be incorporated with decorative, lacquered glass and even Low-e film glasses for beautiful décor, optimum energy efficiency and temperature control.
Acoustic Glass
An airport sees aeroplanes take off and land very few minutes. The noise generated by aeroplanes is powerfully loud. Even within the airport, the hustle and bustle of passengers and staff contribute to noise. This is where the acoustic glass solution comes into play. Created to reduce noise levels and establish a quiet, sound-proof environment, acoustic glass does it efficiently. It lends itself well to incorporation with roof glazed glass, or double glazed glass sections. It also goes well with laminated glass, solar control glass and low-e glass. Imagine if it were raining while you were in the airport, well, the acoustic glass would minimize the sound of the heavy rain rendering a safe, secure environment for you.
Security and Ballistic Glass
The world’s airports have been targets of terrorism attacks in the recent past. Airports around the world have tightened security and more importantly are utilizing security and ballistic glass to resist and block vandalism and terror attacks. Security glass involves two or more glass sheets with an interlayer. The interlayer shatters within the glass in an event of damage thus preventing the whole glass from shattering. Double glazed windows with the appropriate thickness is implemented in creating a security glass. A Ballistic Glass protects the glass from impact of bullets. It safeguards against the glass breaking into small pieces and causing injury. Security and Ballistic Glass are extremely vital for airports to maintain security and safety of operations, staff, and passengers.
An airport is a space where passengers come and go. An airport that takes care of its passengers from the moment they enter to the time they depart is truly good. An airport that takes care of its passengers, and environment both within and outside is even better. Implementing glass solutions is the perfect way to reinvent modern airports.
Content Source: Glasxperts