Insulated glass in architecture

A single unit of insulating glass consists of two or more glass window panes that are separated by a space to reduce heat transfer across the building’s façade. A window that has insulating glass is called double glazing or a double-paned window. Interestingly, there are several more types of such windows. Some of the examples include triple glazing or a triple-paned window, or quadruple glazing or a quadruple-paned window. This depends upon the number of glass panes used in the construction of the window. 

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Glass skyscraper_©fastcompany.com
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Composition of insulated glazing unit_©en.wikipedia.org

Insulating glass units (IGUs) are generally made with glass of thickness between 3 to 10 mm. Glass of higher thickness is used for special functions. Some of the projects even use laminated or tempered glass in IGUs. These glass types enhance the look and feel of the insulating glass units. Commonly, most of the units are manufactured with the same thickness of glass on both the panes. However, in certain projects such as security or acoustic abrasion glass of varying thickness can be used in a unit. The varying thickness of the glass ensures higher performance of the unit. Insulating glass units, or IGUs, are designed in such a way that they keep homes warmer during winter and cooler during summer.

The space between the panes plays a crucial role and provides insulation that is often filled with air. Different gases or a vacuum is commonly used in the space between the glass panes. Argon and krypton are also used in this space as it offers better insulation due to the more density of these gases when compared to air. These gImage 3_ Glazing system_© fivesteeltech.com

ases work well when used with low-e glass coating as they enhance the window’s u-value. U-value is a measure of the heat transmission through a building’s element such as a wall or a window. The lower the u-value is, better the insulating glass unit. 

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Double paneled insulating glass units_©vitrowindowglass.com

When 90% argon gas is filled in a low-e IGU instead of air, the u-value of the window can be improved by up to 16%. Moreover, krypton too improves the u-value in a low-e insulated glazing unit, by up to 27%. However, using a noble gas such as argon and krypton instead of air has few disadvantages. It can increase the time and cost of the window’s construction in an IGU unit.

History of Insulated glass in architecture

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Insulated glazing system_©glastory.net

For several years, single pane glass was commonly used in structures. Though the single pane unit allows light in and blocks the wind, it is a poor insulator. Due to this, it allows heat and cold to pass through the building’s façade. 

In 1865, American inventor and engineer Thomas D. Stetson filed a patent for an insulated glass unit. He discovered that if we replace the humid air between the two glass panes with dry air, insulation could be enhanced. This can also prevent heat loss. 

In the 1930s, Charles D. Haven and John Hopfield patented IGUs under the name Thermopane. The product was promoted by the Libbey Owens Ford company, glass supplier for commercial buildings.

In the 1950s, glass was easily available in the market for commercial use. Several changes were made to make insulated glass units suitable for residential and commercial use. The panel could absorb or release heat in and out while letting in light indoors. Interestingly, glass is extensively used in buildings and structures now. Prominent examples are curtain walls on iconic tall skyscrapers

Modern applications of Insulated glass in architecture

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Insulated glazing system on the building facade_©architectmagazine.com

Due to technology, we have got several types of insulating glazing units. Noble gases are used instead of air between the glass panes. Noble gases such as argon and krypton, are cost effective, colorless, odorless and non-toxic. In addition to this, the use of triple and quadruple paned windows and doors help in maximizing energy efficiency. Use of various glass coatings too help in improving the energy efficiency of glazing units. 

New York Mayor, Bill de Blasio announced that skyscrapers made of glass and steel have no place on Earth. He said that these designs contribute to global warming and other major problems as they are not sustainable. 

Glass has always been a material that is not suitable for large and high-rise buildings. Its glare and temperature control has to be addressed in glass structures. Due to air conditioning systems, the indoor temperature becomes quite favorable. The air conditioning systems contribute to higher carbon footprint.On an average, 60% more than structures that are dependent on natural ventilation.  

Heat and Glare

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Glazing system on the building facade_©fastcompany.com

The United Nations Secretariat in New York, was constructed during the period 1947 –1952. This building was an example of a fully air-conditioned tower with a curtain wall façade. Air conditioning has made it possible to establish high-rise towers in cities with hot and humid climates such as Dubai and Sydney. Though, the heat and glare in these towers was not completely tackled. 

Earlier, central heating systems were used. They used hot water or steam to maintain a warm temperature indoors. Glass was insulated overnight to keep it warm, or was used on the south facades to keep in the heat. These traditional methods were practiced to keep the indoors warm. 

The Crystal Palace

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Painting of Queen Victoria opening the Crystal Palace in London , 1851_© fastcompany.com

In glass structures, maintaining indoor temperature was a challenge. Overheating was quite common. The Crystal Palace in London was a temporary pavilion. The pavilion in Hyde Park, was a home to the works of various industries of all nations in 1851. 

The Crystal Palace is a notable example of a glass structure. It was designed by Joseph Paxton, he was inspired by the design of timber-framed glasshouses. This can also be seen in the design of the Crystal Palace.

The construction of the Crystal Palace was quite steady and time effective. Due to its prefabricated elements and modular construction, it was completed within 10 months. To tackle the issue of overheating, Paxton incorporated various cooling methods. Natural shading and ventilation were one of the major solutions. This also led to the removal of some glass sections permanently. Several large louvers were placed inside the wall that could be adjusted manually by the visitors. This facilitated the ventilation inside the spaces.

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Temperature timeline in the Crystal Palace during May to October, 1851_©fastcompany.com

Despite taking several precautions, overheating became a major issue in 1851. Data was recorded inside the Crystal Palace to observe the temperature during May to October in 1851. The timeline shows the indoor temperature is not favorable. 

These forced the organizers to remove large sections of glazing from the building. Ultimately, the panels were replaced with canvas curtains that were flexible. They could open and close depending upon the heat intensity of the sun. The flexibility of these panels improved the indoor temperature inside the building. 

Well-known Examples 

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Insulated glazing unit on building facade_©fastcompany.com

Notable buildings by renowned architect Ludwig Mies van der Rohe, such as the Lakeshore Drive Apartments (1949), the Crown Hall (1950-56) were designed without air conditioning. Instead, these structures were dependent on natural ventilation and shading to maintain favorable temperatures indoors during summer. 

In the Crown Hall, each panel of the glass wall is supported with metallic iron flaps. Students and staff of the IIT School of Architecture had to manually adjust these panels to create cross-ventilation. Blinds were used to prevent glare and reduce heat gains. Yet, these methods could not provide favorable standards of comfort and air conditioning systems were installed in the buildings. 

Conclusion 

Insulated glazing unit_©all-westglass.com

Glass buildings pose a great threat to the environment. Swiss architect Le Corbusier, had spoken about the design of the UN Secretariat in the 1940s, he believed that the glass surfaces were not suitable for the climatic conditions of New York. As the glass did not have a layer of finish or protection on them. 

On another note, architects and designers often place a strong emphasis on the aesthetics of glass architecture and structures. One of the notable examples is that of the Crystal Palace. The iconic building represents glass and metal as the prime materials that can be used in architecture. In reality, several glass panels were covered with canvas to block out light and heat. Many glass towers in Chicago too used smooth glass panels on facades. They were broken by opened windows and blinds. This places a strong emphasis on finding better materials than glass that do not pose a threat to the environment. 

There is a strong need to reflect upon better surfaces and materials that can be used in architecture. These materials have to be suitable for the environment and climate. This will thereby contribute to conscious design decisions taken by designers and planners. 

Images / Visual Mediums

Image Name : Glass skyscraper

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URL : https://www.fastcompany.com/90350542/how-glass-skyscrapers-took-over-the-world-and-why-we-need-to-stop-building-them

Image Name : Composition of insulated glazing unit

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URL : https://en.wikipedia.org/wiki/Insulated_glazing

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URL : https://www.fivesteeltech.com/aluminum-curtain-wall-low-e-insulated-glass-for-commercial-building.html

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URL : http://www.vitrowindowglass.com/window_glass/understanding_IGU.aspx

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URL : https://www.glastory.net/insulating-glass-types/

Image Name : Insulated glazing system on the building facade

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URL : https://www.architectmagazine.com/technology/products/the-latest-highly-insulating-windows-are-almost-as-efficient-as-a-wall_o

Image Name : Glazing system on the building facade

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Image Name : Painting of Queen Victoria opening the Crystal Palace in London , 1851

Image Number : 8

URL : https://www.fastcompany.com/90350542/how-glass-skyscrapers-took-over-the-world-and-why-we-need-to-stop-building-them

Image Name : Temperature timeline in the Crystal Palace during May to October , 1851

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URL : https://www.all-westglass.com/post/how-insulated-glass-changed-architecture#:~:text=The%20improvements%20made%20in%20manufacturing,buildings%20were%20built%20changed%20forever.

Citations

jaitiwari0 (2022) How insulated glass changed architecture: All-west glass, All. Available at: https://www.all-westglass.com/post/how-insulated-glass-changed-architecture#:~:text=The%20improvements%20made%20in%20manufacturing,buildings%20were%20built%20changed%20forever. (no date). (Accessed: January 7, 2023).

How glass skyscrapers took over the world–and why we need to stop … (no date). Available at: https://www.fastcompany.com/90350542/how-glass-skyscrapers-took-over-the-world-and-why-we-need-to-stop-building-them (Accessed: January 7, 2023).

Insulated glazing (2022) Wikipedia. Wikimedia Foundation. Available at: https://en.wikipedia.org/wiki/Insulated_glazing (Accessed: January 7, 2023).

Understanding insulating glass units (no date) About Insulated Glass Units | Vitro Residential Glass. Available at: http://www.vitrowindowglass.com/window_glass/understanding_IGU.aspx (Accessed: January 7, 2023).

Nischwitz, P. (2022) Insulating glass product types, Glastory. Available at: https://www.glastory.net/insulating-glass-types/ (Accessed: January 7, 2023).

/author/nigel-F-Maynard (2011) The latest highly insulating windows are almost as efficient as a wall, Architect. Available at: https://www.architectmagazine.com/technology/products/the-latest-highly-insulating-windows-are-almost-as-efficient-as-a-wall_o (Accessed: January 7, 2023).

Curtain Wall, round steel pipe, square tube, greenhouse – five steel (no date) Round Steel Pipe, Square and Rectangular Steel Pipe, Greenhouse – Five Steel. Available at: https://www.fivesteeltech.com/ (Accessed: January 7, 2023).

Author

Mahima Aswani is an architect and designer, who has worked on ambitious projects such as the Iraq Pavilion for Expo 2020 and high-end residential and commercial projects. Mahima’s thesis project, Goodbye Slumbai won the Community Design Award in the Senior Thesis Showcase at AUD, Dubai and was published in Dezeen magazine in 2021.

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