The United Nations declared 2022 as the International Year of Glass to promote best practices and sustainability in the industry. Here we discuss its role in buildings and the benefits of technology
The United Nations declared 2022 as the International Year of Glass to promote best practices and sustainability in the industry. Here we discuss its role in buildings and the benefits of technology
Architectural glass allows us to exit and connect with the world outside, giving us access to views and bringing in natural light. One advantage of using glass as a wall element is that it is much thinner than traditional wall materials, providing more floor space.
However, one problem with glass is that along with natural light, it also brings in heat from the outside, which can make interiors uncomfortable in hot tropical climates. In fact, when compared to wall materials such as brick, glass transmits more than double the amount of heat. Additionally, glass can radiate a lot of heat from outside when exposed to direct solar rays, leading to excessive air conditioning use in a hot and humid place like Chennai.
heat resistance
One way to reduce heat transmission during design is to ensure sensible and judicious use of glass with adequate shading to prevent direct heat gain. The use of double glazed or triple glazed windows, where two or three panes are separated by an air gap, ensures better insulation or a very low U-value (measuring the amount of heat from outside ambient air that can pass through the glass ) ) from both heat and noise. In addition, the use of low-e (low emissivity) coatings on the outer layer of the glass will result in increased insulation.
Today, technological advances have given rise to many types of ‘high performance’ glass that let in light (high visible transmittance), not heat (low heat gain). This is made possible by the use of low emissivity (Low-E) coatings on clear glass. These are thin coatings that block or limit certain wavelengths of light from passing through the vane while still allowing the passage of visible light. The tints commonly available in glass are neutrals, blues and greens, all of which provide a good balance between light transmittance and thermal resistance.
St. Gobain’s, Asahi India Limited, Gujarat Guardian Limited and Pilkington India are some of the well-known manufacturers of high performance glass. For those looking for a clear glass aesthetic for their buildings, neutral colors are a close match.
However, to prevent bird hits, it is best to avoid large areas of clear glazing with no partitions higher than two or three storeys in height.
Tips for choosing glass
1. Ideally, it is good to choose a glass with a U-value greater than 5.5. If your lifestyle involves using a lot of air conditioning, it is best to use double glazed windows which will bring the U-value down to 2.6.
2. With regard to SHGC (solar heat gain coefficient is the amount of heat from direct sunlight that falls on and passes through the glass), it is best to look for glass with a factor of 0.5 or less. When this is combined with ample shading, the factor is reduced even further. If you have large windows in your home or workplace, especially in a place like Chennai facing east or west, you can look for glass with an even lower SHGC factor of 0.35. However, keep in mind that the cost of glass increases as the SHGC decreases. A good strategy is to select glass with a moderate SHGC factor, but ensure adequate sun shading on the building.
3. To ensure adequate visible light transmittance within buildings with small windows, it is best to look for glass with a VLT (Visible Light Transmission) of at least 50%. In the case of a large glass facade, a VLT of at least 35% is good.
Conscious selection of glass can not only go a long way in ensuring our own thermal comfort, but will also reduce environmental pollution caused by excessive air conditioning and provide substantial energy savings over time.
‘Glass buildings use less electricity’
AR Unnikrishnan, MD, Glass Business, Saint-Gobain India says, “The indoor environment of 30 offices across the country was assessed by Green Business Certification Institute (GBCI) India and Saint-Gobain Research India (SGRI). Workspaces in India The study was a comprehensive exercise carried out over a period of three years. The study highlights some important issues, such as poor ventilation, improper lighting, and others. Among ineffective noise control. There are four main factors that affect people’s experience of comfort in an indoor environment. They are thermal comfort, visual comfort, acoustic comfort and indoor air quality. It has been observed that only 10% of offices open in the morning. EML is described as a way to measure the biological effects of light on humans. Comfort lighting does not cause glare or blindness. When people are in good light working in places If so, they are more productive. According to the study, commercial buildings with glass use less artificial light, consume less electricity. The overall energy savings for buildings that use natural light varies from 15% to 40%. About 74% of people reported no outside views or only poor-quality views from their workstations. People with good outdoor views had higher energy levels at the end of the day. Thermal comfort is that state of mind that expresses satisfaction with the thermal environment in all seasons. According to research, over 56% of places operate on the cooler side of the comfort zone.
Acoustic comfort is achieved by the absence or reduction of unwanted sounds from external sources such as local traffic or internal sources such as office equipment, and people talking. The study shows that in 73% of the locations, the level of internal background noise exceeded the standard limit.
Since we spend more than 90% of our time indoors, our indoor environment and its systems significantly affect the quality of the air we breathe. In 73% of the locations, the level of three or more contaminants did not meet the prescribed limits. Volatile organic compounds (VOCs) in building materials are primarily the root cause of unhealthy air quality. Glass as a building material not only has no VoC, but is also odorless.
Joint research suggests that offices should prioritize the evaluation of their internal environments and take necessary action to improve them.
The author is the founder of Green Evolution, a sustainable architecture firm.