Is glass the building material for the future or a hazardous, unsustainable choice? We seek to separate fact from fiction.
Billows of smoke engulfing a glass high rise - a sight now increasingly common in cities. In the past two years itself, there have been three fires in glass towers in Mumbai and Kolkata. And such incidents have had people asking the question: Was glass responsible?
Against this backdrop, CW takes a closer look at glass as a building material to separate fact from fiction, and seeks to ascertain how glass can be sensibly and sustainably used in our structures.
Fact or fiction
Is glass a fire hazard? Many people believe glass structures turn into towering infernos in case of fire, a veritable death trap. However, B Santhanam, Founder & Managing Director, Saint-Gobain Glass, India, disagrees. ´If proper consideration is given to the safety aspect of a structure, incidents like fire will not require a scapegoat in the form of glass,´ he insists, saying that fire safety mechanisms must be in place. For his part, Vikram Khanna, COO-Architectural Institutional Business, COO - Consumer Glass, CMO, CIO, Asahi Glass India Ltd, views faulty maintenance of fire exits as the culprit. ´In fact, using high-powered glass like fire-retardant glass (FRG) actually provides adequate response time during an eventuality,´ he adds. (Read the full interview on pg 88). FRG glass comes in different variants that correspond to the duration it can withstand fire and the distance between the glass structure and the inhabitants. Further underlining the need for better safety mechanisms, KC Jain, President, HNG Float Glass Ltd, says, ´One needs safety hatchets made of tempered glass that can be broken in case of an emergency, along with ventilated openings at intervals. Including these systems right from the planning stage will help reduce the risk of damage in case of any eventuality.´ Citing these as basic precautions for every high-rise building, he says cutting corners is most often the reason for accidents. ´Globally, glass is being used much more extensively, yet any fallout is minimal owing to adequate safety measures.´
Is glass a safety hazard? In terms of safety, Vikram Pawar, Urban Conservation Architect, Studio Architecture, argues,´Although glass is counted as a fragile material, using certain types of glass like toughened or laminated glass can work as an insurance in the event of shattering.´
The protective properties of the glass makes shards stick to the laminate in the event of breakage, thus ensuring safety. However, the term ´safety glass´ can sometimes be a misnomer. As Roshin Mathew, President-Engineering, Brigade Group, points out, ´Wired glass, though fire retardant, should not be used as safety glass, as the strength of wired glass is even lower than annealed glass and it can be dangerous in case of any breakage.´
Is glass an environmental hazard? The major complaint against the use of glass, especially in a tropical climate like that of India, is the ´heat island effect´. The insulating quality of glass tends to trap in the heat along with letting in natural light, and using reflective coat at the same time can heat up the surroundings. However, dubbing the effect and other misgivings about glass as outdated, Santhanam says, ´With technological advancement, the new high-performance glass available has made it possible to keep about 85 per cent of heat away while allowing unrestricted access to natural light.´ Chitra K Vishwanath, Architect, Biome Environmental Solutions Pvt Ltd, sees it differently. ´Investment in high-powered glass is expendable, especially in the Indian context, if natural ventilation is provided as it is bound to be cheaper than any glass installation,´ she insists.
Focusing on the planning aspect, Soumya Raja, Architect, Traction Studio, says, ´Having un-shaded glass façades in the south and west instead of the more traditional north opening where glass can play an important role is the primary reason of heating up of the interiors.´ Indeed, in the absence of proper planning, it is possible that a glass building can end up utilising more energy for its HVAC system than saving lighting costs. Nevertheless, Manju Yagnik, Vice Chairperson, Nahar Group, maintains, ´Long-term energy saving is possible, especially if glass is used intelligently in commercial structures where energy usage is uncontrollable.´ Many experts view the heat island effect, then, as more of an urban and design flaw rather than a shortcoming of glass. Proper planning and urban landscaping of areas surrounding the structure can negate this island effect. In fact, globally, glass buildings in planned cities contribute only marginally to urban heating.
Use vs. misuse
All considered, Khanna blames ignorance as the main reason for the less-than-stellar reputation of glass, and says, ´The ´misuse´ of glass is more prevalent than its use.´ It is certainly true that awareness of glass as a construction material on the whole is quite low. Incorrectly designed buildings, using inappropriate types of glass inaccurately and skimping on quality, coupled with ignorance on technological developments, set the stage for disaster.
For her part, Vishwanath says, ´The embodied energy of glass is higher than any other construction material, so it is not prudent to use glass extensively.´ The main benefit of glass, in her view, is that it provides security against harsh external conditions, especially in a chaotic urban environment filled with dust and noise pollution. So the usage of glass should be limited in areas where ventilated openings are not possible.
´A knowledge-based approach towards glass applications, not relying on borrowed imagery from the West or the Far East for buildings incompatible with Indian climatic conditions, is necessary to stem the abuse of the material,´ says Pawar. Echoing the sentiment, Raja says, ´Glass represents modernity and a futuristic image, but systematic and standardized industry of coating façades with glass has ensured that as a construction material it is not exploited for its full potential.´
While the skeletal quality of glass is exploited for few extra square feet of carpet area, it is not enough to subset the energy consumption cost. Vishwanath adds, ´While determining the pros or cons of any construction material, a macro view has to be taken - an isolated examination will not provide accurate results.´
Clarity and sustainability
To remove the stigma still attached to glass in some quarters, Jain calls for all stakeholders in the construction industry to come together and insist that the government put in place a proper building codes, especially with regard to glass, which includes fire safety and energy consumption among other issues to ensure proper implementation. Although the Energy Conservation Building Code (ECBC) has basic guidelines on the way, glass should be used in façades, as it is voluntary, it is also arbitrary in applications. The unorganized and erratic demand for glass without a single unified building code makes it difficult for the glass industry to understand the needs of the sector and undertake measures to address the same.
According to Santhanam, ´The problem lies in regulation, in not implementing the building code, improper design and planning. Heat-soaked processed glass has to be used according to regulations globally but the situation is not the same in India where unchecked influx of low-quality glass shatters or breaks.´
Sustainability is another concern. ´The manner in which glass is used architecturally determines its sustainability aspect,´ says Deepak Gahlowt, Architect and Hon. Convener, CCPS. ´There is a need to use solar shading devices while maintaining a good glass-to-wall ratio.´
The orientation of the structure and even the city plays an important role in extracting the maximum potential from glass. While building smart cities, which would invariably see a lot of use of glass, orientation along the direction of the wind should be thoroughly planned.
In essence, there is a need to go back to the basics and integrate the advancements in the architectural sector to an Indian context so every structure can become sustainable in terms of energy saving, safety and security.
´With the continually evolving technology in glass and aluminum systems used to hold glass, the demand for glass has grown at a rapid rate in the last decade,´ says Mathew. Indeed, glass, if understood and used well, holds tremendous potential, especially owing to its many innovative features. For instance, Saint-Gobain Glass India, through its Saint-Gobain Vetrotech fire-resistant solutions, offers the Contraflam range, also known as the ´world´s toughest fire-resistant glass´. The company has supplied its products to many structures across the country, including Diamond Square, Mumbai; Suncourt, Noida; and The Leela Palace, Chennai. Focusing on safety, Asahi India Glass Ltd produces tempered, heat-soaked and laminated glass that provides structural integrity. The company´s products have been used in the new Reliance campus in Navi Mumbai and will be seen in the upcoming Reliance Twin Tower project, also in Navi Mumbai.
Further, the development of high-powered glass has even led to it becoming a cost-effective option to be used in certain places against brick and mortar. One sq m of brick weighs around half a tonne, but a glass plane in its place weighs only one-seventh to one-fifth of the brick, making it lightweight. Thus, many structures are using glass in conjunction with steel to slash the weight of the entire structure, resulting in reduction of the foundation and duration required to complete construction.
Also, with sustainable building gaining currency, there has been an increase in the use of high-performance glass in green-rated buildings along with a growing market in residential townships. There is a steady growth in the processed market segment, with more people leaning towards double-glazed glass to cut out noise and heat, and laminated windows replacing grills. There is also an increase in demand for lacquered glass being used in interiors as partitions as it is only 50-mm thick compared to 150 mm for a normal brick wall.
Going forward, such value-added products and variety of applications are sure to spur growth for glass. One major hurdle for the Indian glass industry remains the influx of cheap but low-quality imports from West Asian countries. With steps being taken to levy anti-dumping charges on these imports, the Indian industry remains confident that true quality will, ultimately, shine.
Classification of critical locations
Intelligent use of glass will allow for full capitalisation of its assets.´
- Manju Yagnik, Vice Chairperson, Nahar Group
The embodied energy of glass is higher than any other construction material.´
- Chitra K Vishwanath, Architect, Biome Environmental Solutions Pvt Ltd
Glass façades should be used in North openings.´ - Soumya Raja, Architect, Traction Studio
Reliance on borrowed imagery from west and far east should be reduced.´ - Vikram Pawar, Urban Conservation Architect, Studio Architecture
Fallout of glass, globally, is minimum owing to adequate safety measures.´ - KC Jain, President, HNG Float Glass Ltd
The non-implementation of the building code, improper design and planning is the problem.´
- B Santhanam, Founder & Managing Director, Saint-Gobain Glass India
There has been a continuous evolution in glass and aluminium systems to hold glass.´
- Roshin Mathew, President-Engineering, Brigade Group
Sustainability of glass
depends on its applications.´
- Deepak Gahlowt, Architect and Hon. Convener, CCPS
Industry growth: Anticipated around 15%.
Tilt towards double-glazed glass and laminated glass.
Innovations: High performance heat soaked and solar glass.
Demand: Residential buildings; Tire II and III along with upcoming smart cities.