A Clear Winner
Once viewed as a delicate accessory, glass is growing tougher thanks to modern technology. Apurva Bose Dutta scrutinises the material that’s redefining contemporary architecture.
Contemporary architecture has rebuilt its rhetoric through the use of certain materials, of which glass could well occupy the prime position in bestowing a modern look to buildings. It has injected vitality in interior spaces by virtue of its transparency and translucency.
The initial use of glass was for windows, which led to it being used as a decorative feature. But by the 20th century, glass began to be redefined thanks to its employment in skyscrapers.
Today, one associates corporate offices in India with glass that fulfils both needs – of a building’s interior and exterior. Interestingly, glass is also finding its way into homes, besides retail spaces, hotels, hospitals, exhibition spaces, airport
terminals and concert halls.
It can even be used to span a wide roof structure, as in Mumbai’s Raghuleela Mall – whose focal point is its atrium covered by a conical glass skylight.
In fact, the structural use of glass is a major shift. Renowned architect Jasbir Sawhney says, “Glass is a material of the 20th century, as it allows the continuity of the interior spaces to the exterior. That was when continuous spaces began to be created for the first time.”
In the Hyatt Regency hotel in Kolkata designed by Sawhney, the all-glass façade of the café on the ground floor makes the exterior water body travel inside through the glass, creating an illusion of actually sitting in the garden. The use of glass for
curtain walling in the guest rooms and public areas is also very contemporary.
Today, glass is no more a ‘fragile’ material but has emerged stronger and safer. Gone are the days when heating or cooling bills soared due to fully-fronted glass buildings.
With innovations like double-glazed glass, thermal-insulating glass and solar-control glass, this has become one of the mostsought-after green building materials.
In the Salarpuria SoftZone building in Bangalore, the glass used has a light transmission of 60% and cuts 42% of the heat entering the building – leading to a saving in costs. On the other hand, for the Infosys building at Chennai which has a hot climate, glass that has a transmission of 18% (which cuts about 78% of the heat entering the building) has been chosen.
With the advent of self-cleaning glass, maintenance of the structural material is no longer a problem. One now sees the production and application of microscopic coatings on glass, which can make the required changes to its natural properties.
Raghunandan SK, senior manager, Sales, Dorma India Pvt Ltd (which also manufactures patch fittings for glass, sliding systems, glass folding partitions, etc) says, “Consumption of glass is almost 40-50% in interiors. Gradually, gypsum partitions will be replaced by glass partitions.”
Speaking about the demand for safety glass, Mohammed Riyaz, managing partner of Chennai-based Atlas Marketing Co, importers and distributors of Zeal architectural hardware/glass solution providers, cites Chennai – a city that has three glass-tempering units; production plants of major glass manufacturers like Saint-Gobain; and dealers experiencing a good sales growth in glass.
Initially, there used to be only one or two glass technical installers, but now there are more than 15 professional glass technical installation companies in Chennai alone.
Architect Ramesh Khosla, senior partner of international architectural firm the Arcop Group, points out that today glass has a wide range of coatings, colours and technical characteristics that allow architects and designers to explore the aesthetic and functional possibilities of exterior and interior light, while meeting complex energy and performance requirements.
The use of glass has helped to reduce dependence on artificial light, leading to a considerable drop in electricity consumption. Besides being recyclable, high-performance glass controls the thermal heat indoors – thus helping to maintain the temperature. Acoustic comfort is also high with double-glazed glass facades.
In the Montreal World Trade Centre, a joint venture of Arcop Associates, architects, and Provencher Roy Architects, the appropriate use of glass makes the pedestrian mall resemble the outdoors during daylight hours, sans the outdoor temperature.
Flat glass qualifies as one of the oldest man-made materials; but with the advent of new technologies, glass has found itself in almost everything – from railings, shower cubicles, skylights, shop fronts, floors and revolving doors to skywalks, staircases, shelves, ceilings and interior partitions.
Its flexibility is a boon to designers. Further, glass facades help in blending the interiors with the exteriors.
PROS AND CONS
“Glass is colour, glass is light, glass is status, glass is privacy, glass is beauty, glass is aesthetics. It is value for money,” declares Rajiv Milkha Singh, manager of distribution in Karnataka of Saint-Gobain Glass India Ltd.
Riyaz points out that glass has become a common product in today’s construction industry, where it has replaced brick walls, ceilings and tiled floors. There are more advantages in using glass today, as a number of safety features have been included. For instance, when tempered glass breaks, it disintegrates into small blunt pieces that safeguard against harming people.
Glass can open up a space and make it look larger, besides taking away the closed character of any space. It can define space without making visual boundaries.
Its aesthetic appeal, play with light and ability to bind the interiors and exteriors facilitates multiple usage. Its durability, coupled with resistance to corrosion, is another advantage.
A building using glass can still convey a new look even after a number of years due to the low maintenance required. Being a good electrical insulator, glass can generally be seen in light fixtures too. Shatter-proof glass, though expensive in India, is used for shop fronts and can aid in security.
Sometimes glass is used on the exterior of buildings like an artificial skin that imparts an aesthetic look to the structure. When used as a façade element, it makes the structure seem lighter.
Architect Ramesh Khosla adds, “Being a prefab material, a glass wall can be erected in a very short span of time (together with wall assembly systems) without the use of water.” According to Raghunandan, glass occupies less space in partitions as compared to gypsum and masonry partitions.
Once processed, glass is much safer since it becomes four times stronger. Handling glass is entirely different from handling concrete or brick structures and calls for technical expertise, but unfortunately there is a shortage of skilled manpower. The efficient use of glass needs to be made a matter of study.
Saint-Gobain Glass India Ltd has launched the Saint-Gobain Glass Academy to disseminate information, technology and training in the safe and efficient use of glass in construction.
Among the disadvantages, Raghunandan lists the cost factor of toughened glass. But Singh insists, “Glass is not a costly material.
It fares better than concrete. Yes, bulletproof glass can be expensive, but single and double-glazed glass cost less than concrete.”
Raghunandan also feels that the heat radiation is more when glass is used in external application. Identifying another potential disadvantage, Singh adds that if glass is used in an annealed state without toughening, it can cause injury
when it breaks.
RELEVANCE TO INDIA
Though glass is becoming the most favoured material for facades in India, there are debates about whether it is relevant here. Western countries, due to their climate, need to use glass extensively in order to capture sunlight.
But is it justified to use the material in India, just to achieve an international look? What’s important is how we use glass in our buildings.
Giving a good shade to glass exteriors is preferable. In the upcoming Circular Towers at Jaypee Greens at Noida, designed by the Arcop Group, glass has been used diligently.
Subtle shading devices coupled with quality of glass and varying shades of colour make these towers look exciting.
Glass is generally chosen either on the criteria of performance needs or aesthetic needs. In climatic conditions like India, glass with high-performance solar ‘control’ coating should be used. Very often, we see structures where glass hasn’t been combined with the other materials sensibly.
This can make a building look cold and out of context. Conferences on glass have concluded that certain codes for reflective glass are yet to be introduced in India. At present, it is possible that one building can reflect the glare from a building located opposite it.
India has some fine examples of the use of glass in buildings. Chennai-based VV Architects Pvt Ltd have designed a green building for Sew-Eurodrive, a German multinational that makes quality gear motors.
Glass is used here in innovative ways around the fish pond, as skylight, as treads for the steps, or sloping glass which is north facing. Vineeta Badawe, director, adds, “We like to use glass in moderation and restrict full glazing to usually unoccupied areas or where the view is exciting.”
The Wipro Technologies Gurgaon Development Centre is the greenest building in India and the second greenest in the world. Designed by architect Vidur Bharadwaj, the use of glass here helps ensure daylight and exterior views for more than 90% of the occupants. The air-conditioning expenses are also kept to the minimum due to the energy-efficient glazing.
TYPES OF GLASS
There are various types of glass for use in specific areas. Clear sheet glass is used for ordinary glazing as well as better and special quality products i.e. for pictures, doors of cupboards, etc.
Polished plate glass which is ground and polished to produce an undistorted finish is used for general glazing, high-class work and silvering for mirrors, besides load-bearing functions such as shelves and tabletops.
Georgian Wired Polished Plate has a wire mesh incorporated within it which holds the glass if it breaks. It also has some fire-resistant qualities.
Toughened (tempered) glass is a flexible and impact-resistant glass used for doors, balustrades, etc.
Laminated glass, which is two or more layers of glass usually with a plastic film in between, is used for safety in high-impact areas. Then there are anti-bandit types of glass that may resist intentional attack such as gunfire or hammer impact.
They can also be used for skylights or sloped glazing applications. Patterned glass is translucent glass with linear or geometric patterns embossed.
Tinted glass is semicoloured to absorb solar radiation, reduce glare as well as heat build-up. Reflective glass has a transparent metal coating to decrease the amount of solar energy passing through.
Insulating glass has two layers of glass separated by a hermetically-sealed airspace in order to provide thermal insulation and restrict condensation.
Glass bricks, etched glass and sandblasted glass panels are also increasingly finding their way into buildings. For aesthetic purposes, varieties like smoked glass, wire glass, frosted glass and Pyrex glass have been designed. Decorative etched coloured glass is used in interiors.
Glass blocks are an upcoming construction material. They have proved to be an excellent material for acoustic and thermal insulation, water-proofing, energy conservation and abrasion resistance, besides interior and exterior decoration purposes.
They can even be used for interior divisions or to construct walls separately.
Saint-Gobain has innovative products like the planilaque (a lacquered glass in nine vibrant colours, mainly used for wall panelling, shower cubicles and kitchens as it is highly resistant to humidity and is formaldehyde free), master and decor glass (pattern glass, which can be tempered to ensure safety; tinted mirrors in green, bronze and grey), fire-rated glass and Privalite (intelligent glass). The focus today is shifting to photo-voltaic and solar thermal systems, apart from thin fill technology.