Glass – A Choice for Green Building

With the presence of global warming and ecological problems becoming a huge problem over the last few decades, every industry is trying to use materials that will lessen the effects of the same. With the use of sustainable material increasing day by day in the world, property developers and real estate companies are also doing their bit in improving the environment for a better future. This has led to the rise of green buildings.

Buildings across the world have a tremendous environmental impact during their life. Globally, Buildings are responsible for at least 40% of energy use. Construction of new buildings generate large amount of solid waste and in turn, disturb natural habitat & vegetation.

A green building is one which uses less water, optimises energy efficiency, conserves natural resources, generates less waste and provides healthier spaces for occupants, as compared to a conventional building. Green buildings offer immense potential to reduce consumption & regenerate resources from waste and renewable sources. Thus, the intent of a green building design is to curtail the demand on non-renewable resources, amplify utilization efficiency of these resources when in use, and augment the reuse, recycling, and consumption of renewable resources.

Glass is playing a vital role in helping engineers and architects construct and design passive or low energy constructions, which qualify to be labelled as 'green.' It has a wide range of functional benefits. Its transparency allows day-lighting of the interiors and integrates the interiors with the exteriors. Studies have proven time and again that this substantially improves the productivity and health of the occupants of the building. Glass is completely recyclable and non-toxic in nature. It satisfies all the ecological parameters of being the most sought after “green” building material in Green Buildings. Moreover it harmonizes a structure with its environment.

Glass has varied “Green” benefits of which, some of them are :

1. Day-lighting 
The use of glass brings in lot of light that helps in giving a high amount of natural day lighting instead of depending solely on artificial lighting thus reducing considerably electricity consumption.

2. Blending interiors with exteriors 
Glass facades give a spectacular view of the outside world from the cozy interiors.

3. Recyclability
Glass being recyclable satisfies the important parameter of being a “Green” building material.

4.  Achieving energy efficiency
High performance glass helps in controlling the solar and thermal heat in the interiors and helps to maintain the temperature at its minimum best and in turn helps to turn down the air-conditioning expenses.

5. Innovative application
Being very flexible building material glass helps to satisfy and capture an architect's utmost imagination in its shape and form.

6. Controls noise
Double glazed glass facades help in achieving a high degree of acoustic comfort by keeping away noise penetrating from the exteriors to the interiors thus ensuring a calmer atmosphere inside.

7. Self-Cleaning
The future belongs to self-cleaning glass which keeps itself clean on its own and brings out an ever sparkling effect.

Types of Glass used in Buildings

Nowadays, a vast array of glass and glazing solutions exists to satisfy the needs of the most ambitious architects and building engineers who want to design and construct low energy or passive buildings.

Float Glass : Float glass is also called soda lime glass or clear glass. This is produced by annealing the molten glass and is clear and flat. It has too much transparency and can cause glare. It is used in making canopies, shop fronts, glass blocks, railing partitions, etc. It is available in standard thickness ranging from 2mm to 20mm and has weight range in 6-26kg/m2.

Tinted Glass : Certain additions to the glass batch mix can add colour to the clear glass without compromising its strength. Iron oxide is added to give glass a green tint; sulphur in different concentrations can make the glass yellow, red or black. Copper sulphate can turn it blue. Etc.

Toughened Glass : This type of glass is tempered, may have distortions and low visibility but it breaks into small dice-like pieces. Hence it is used in making fire resistant doors etc. They are available in same weight and thickness range as float glass.

Laminated Glass : This type of glass is made by sandwiching glass panels within a protective layer. It is heavier than normal glass and may cause optical distortions as well. It is tough and protects from UV radiation (99%) and insulates sound by 50%. Used in glass facades, aquariums, bridges, staircases, floor slabs, etc.

Shatterproof Glass : By adding a polyvinyl butyral layer, shatter proof glass is made. This type of glass does not form sharp edged pieces even when broken. Used in skylight, window, flooring, etc
Extra Clean Glass : This type of glass is hydrophilic i.e. The water moves over them without leaving any marks and photocatalytic i.e. they are covered with Nanoparticles that attack and break dirt making it easier to clean and maintain.

Double Glazed Units : These are made by providing air gap between two glass panes in order to reduce the heat loss and gain. Normal glass can cause immense amount of heat gain and upto 30% of loss of heat of air conditioning energy. Green, energy efficient glass can reduce this impact. 

Chromatic Glass : This type of glass can control daylight and transparency effectively. These glass are available in three forms- photochromatic (light sensitive lamination on glass), thermochromatic (heat sensitive lamination on glass) and electrochromatic (light sensitive glass the transparency of which can be controlled by electricity switch.) It can be used in meeting rooms and ICUs

Glass wool : Glass wool is a thermal insulation that consists of intertwined and flexible glass fibers, which causes it to "package" air, and consequently make good insulating materials. Glass wool can be used as filler or insulators in buildings, also for soundproofing. 

Glass Blocks : Hollow glass wall blocks are manufactured as two separate halves and, while the glass is still molten, the two pieces are pressed together and annealed. The resulting glass blocks will have a partial vacuum at the hollow centre. Glass bricks provide visual obscuration while admitting light