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Advantage - Glass

Glass for all heights


Our cities are growing into the skies. Skyscrapers, aka high-rise buildings, are the new norm. The demand for housing and commercial complexes, thanks to burgeoning population and increased jobs, is on the rise. As the supply of land is limited, cities can only grow vertically.

with high-rise architectural marvels dotting the urban skyline, concrete does not support a vast range of functions. Worse still, concrete adds to the weight, does not provide space for creativity and, in one sense, is ugly.  In vertical development, weight of the building as also aesthetics play a significant role. Glass, with its qualities of flexibility and durability, is a preferred material for construction. 

There are several other reasons as well:

One, being a lighter building material, glass reduces total building weight. The density of a brick wall can be up to 2000 kg/m3 while glass’ density is only around 2.51 g/cm3.   In a typical high-rise building of 70 storeys with 90,000 m2 of glass area, the estimated weight reduction by using glass is 36,900 tonnes! That’s not a small number. 

Two, glass has lower envelope thickness that saves up to 8 per cent of the construction area and, in turn, increases usable carpet area.  This increase in carpet area makes glass exciting for residential buildings as well. 

Three, glass is easy to install. In a day, about 150 m2 of glass façade can be built while only 70 m2 of brick wall can be constructed. 

Glass can be fabricated in three types - Semi-Unitised system, Unitised System and Frameless Façade - based on needs. With its wide style and colours and also customisable properties, glass stimulates the architect’s ‘Imagineering’ and is the first choice construction material for urban high-rise buildings. 

ADVANTAGE - GLASS

Glass can be customised for a particular use. Providing seamless entry to natural light, glass offers an open and spacious look. Sunlight generates less heat compared to artificial lighting and thus a flat 40-60 per cent reduction in power costs. For clear glass, every five sq. metre requires 1TR of air-conditioning; in coated glass every 16 sq. metre requires 1TR of air-conditioning. 

An analysis of the energy consumption pattern of both the residential and commercial segment shows about 70 – 80 per cent of energy consumption goes for lighting and air-conditioning. Glass façading provides a range of solutions to reduce this. 

In an office space in Mumbai, we calculated the energy savings with different types of glass facades - No Glazing (all Opaque walls), Single Glazed Clear Glass, Double Glazed Clear Glass, Double Glazed Normal Reflective Glass and ECBC Compliant Reflective Glass. With single glazed clear glass as the base, the saving per year in kWh are 68, 292, 466 and 541 respectively. A 14 per cent savings on total consumption was found using ECBC Compliant Glass.

Fire prevention and protection are vital for high rises. Glass as a fire-resistant wall, can withstand fire for about 120 minutes. 

Glass can be toughened to make room partitions, strengthened and tested for seismic pressures and also provide for excellent acoustics.

Even a quake cannot crack toughened glass

Though glass brings in an image of being brittle, technology has enabled it durable and seismic-resistant. Unlike concrete buildings that collapse, glass can be treated to withstand earthquakes. Analyses of impact of earthquakes world over showed that during earthquakes, concrete buildings crumbled to rubbles; but glass buildings suffered just a few minor cracks. So efficient is seismic-resistant glass!

Apart from these benefits, glass being a non-dirt absorbing material, is easy to clean and maintain. Unlike concrete buildings which require repainting every 5 years or earlier involving a huge spend, glass can be easily cleaned, instantly bringing back freshness. 

With its ease of maintenance, glass can withstand time, temperature and weather. In cold western countries, thermal insulated glass helps maintain heat within the rooms; to beat the heat in the hot eastern world, solar control glasses allow only light and not heat. A single material that could be customised for contrasting uses!

Glass is so ‘green’! Totally recyclable!

Broken glass is a primary raw material to manufacture glass. Its manufacture is less energy consuming than cement or concrete. CO2 emissions in concrete buildings are higher by 6 to 7 per cent and consume about 4 GJ of energy in electricity, process heat and transport while glass-making consumes as low as 12 MJ of energy for manufacture and processing. 

In the rapidly unfolding era of smart buildings and IT expansion, glass will play a significant role. The emphasis will shift from power consumption to energy generation. Recent developments like LED integrated glass façade, Electrochromic, Photovoltaic façade, etc., are in this direction. 

Hassle-free maintenance, aesthetics along with the multitude of options make glass a preferred material for construction. The commercial segment has realized it; the waking point of the residential section is happening. With more high rises, glass provides the necessary durability at reduced weight and cost. 

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