THE DISCOVERY OF GLASS IN ARCHITECTURE WAS ANOTHER BREAKTHROUGH. SUGGEST WAYS IN WHICH GLASS CAN BE USED IN ENHANCING BUILDING CONSTRUCTION?

Glass has been a fascinating material to humankind since it was first made in about 500 BC. At first thought to possess magical properties, glass has come a long way. It is one of the most versatile and oldest materials in the building industry. From its humble beginnings as a window pane in luxury houses of Pompeii to sophisticated structural members in new age buildings, its role in architecture has evolved over the years. a brief history of glass in the building industry In prehistoric times, Obsidian (Naturally occurring glass found near volcanic regions) and fulgurite (glass formed naturally after lightning strikes sand) were used to make weapons. Manmade glass was used as a luxury material was used in decorations, jewelry, vessels and crockery. Glass blowing was discovered in the 1st century in Europe, this revolutionized the glass making industry. The technique spread throughout the Roman Empire. Production of Clear glass, by introduction of manganese dioxide, saw glass being used for architectural purposes. Cast glass windows began to appear in the most important buildings and villas in Rome and Pompeii. Over the next 1,000 years glass making spread through all of Europe and Middle East. In 7th century Anglo Saxon glass was used in churches and cathedrals By 11th century sheet glass was made by the crown glass process. In this process, the glassblower would spin molten glass at the end of a rod until it flattened into a disk. The disk would then be cut into panes. By 13th century, this technique was perfected in Venice. Stain glass windows were used in gothic renaissance and baroque architecture from the 11th to the 18th century. The examples of stunning patterns created by using colourful glass are immortalized by great artists all over the world. The Crown glass process was used up to the mid-19th century. in the 19th century, flat / sheet glass windows were used in making windows. These were completely flat and did not have any optical distortions. But glass was still an item of luxury as it took large resources, brilliant skill and immense energy to be produced. In 1958 Pilkington and Bickerstaff introduced the revolutionary float glass process to the world. This method gave the sheet uniform thickness and very flat surfaces. Modern windows are made from float glass. From the beginning of 20th century modern architecture has been instrumental in mass production of concrete, glass and steel buildings in the factories we call cities. This ideology helped accommodate housing needs of the burgeoning middle class. Glass and steel construction have become the symbol of development in many countries, where people tend to see these buildings as symbols of affluence and luxury.

Engineering Properties of Glass

 Transparency 
Strength 
Workability 
Transmittance 
U value 
Recycle property 
Transparency of Glass

Transparency is the main property of glass which allows the vision of outside world through it. The transparency of glass can be from both sides or from one side only. In one side transparency, glass behaves like mirror from the other side. 

Strength of Glass Strength of glass depends on modulus of rupture value of glass. In general glass is a brittle material but by adding admixtures and laminates we can make it as more strong. 

Workability of Glass A glass can be molded into any shape or it can be blown during melting. So, workability of glass is superior property of glass. 

Transmittance The visible fraction of light that passing through glass is the property of visible transmittance.

 U value of Glass U value represents the amount of heat transferred through glass. If a glass is said to be insulated unit then it should have lower u value. 

Recycle Property of Glass Any glass can be 100% recyclable. It can also be used as raw material in construction industry.

CONTEMPORARY PRODUCTION Following the glass batch preparation and mixing, the raw materials are transported to the furnace. Soda-lime glass for mass production is melted in gas fired units. Smaller scale furnaces for specialty glasses include electric melters, pot furnaces, and day tanks.[3] After melting, homogenization and refining (removal of bubbles), the glass is formed. Flat glass for

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windows and similar applications is formed by the float glass process, developed between 1953 and 1957 by Sir Alastair Pilkington and Kenneth Bickerstaff of the UK's Pilkington Brothers, who created a continuous ribbon of glass using a molten tin bath on which the molten glass flows unhindered under the influence of gravity. The top surface of the glass is subjected to nitrogen under pressure to obtain a polished finish.[22] Container glass for common bottles and jars is formed by blowing and pressing methods. This glass is often slightly modified chemically (with more alumina and calcium oxide) for greater water resistance. Further glass forming techniques are summarized in the table Glass forming techniques. Once the desired form is obtained, glass is usually annealed for the removal of stresses. Surface treatments, coatings or lamination may follow to improve the chemical durability (glass container coatings, glass container internal treatment), strength (toughened glass, bulletproof glass, windshields), or optical properties (insulated glazing, anti-reflective coating). Pilkington process: Large quantities of raw materials (clear sand, calcium oxide and sodium carbonate)are brought to the glass production plant. They are then weighed and mixed in the right proportion. Certain admixtures are added to the batch to give the glass appropriate proprieties or colour. The mixture is then heated in a gas fired furnace or electric smelter, pot furnace or kiln. Quartz sand without additives becomes glass at a temperature of 2,300 degrees Celsius Adding sodium carbonate (soda) reduces the temperature need

WAYS IN WHICH GLASS IS USED IN ENHANCING BUILDING CONSTRUCTION

Glass in Buildings are at the heart of modern architecture, engineering and construction. They play a beneficial role in addressing some of the major environmental challenges of buildings, new and old.

Architects increasingly seek to bring natural environmental factors into the interior of buildings by maximizing natural daylight. This is achieved through the use of larger glazed areas in façades and roofs, and entirely glazed façades, where the glass is a structural component of the building. Energy-saving is a key driver. CO2-reduction targets have driven tougher legislation for energy-saving glass, making insulating glass units’ mandatory in much of Europe. This has now developed further into legislation requiring energy-efficient glass. In hot climates, reliance on air conditioning, which would otherwise be increased by such larger glazed areas, is mitigated by the use of advanced solar control glass, allowing the sun’s light into buildings, while blocking much of its heat.

In cold airports, low-emissivity glass reduces heat loss, while allowing high levels of valuable free solar gain to heat buildings without significant loss in natural light. However, in the summer, unless combined with solar control glass, it can become uncomfortably hot. Fire-resistant glass also has an important role to play in promoting the sustainability of communities. The correct choice of glass can help to reduce the capital outlay, running costs and associated carbon emissions of buildings.

 Sustainability in buildings Glass is used extensively in most buildings, in both exterior and interior applications; as a construction material, for functionality, for decoration and for interior fittings. Around the world, policy-makers are beginning to realize how the quality of buildings affects the quality of the environment and of people’s lives. Glass play a vital role in improving energy efficiency and reducing CO2 emissions. But they also offer other advanced functionality; fire protection, noise attenuation, safety and security, privacy, decoration and even self-cleaning properties.

 Energy efficiency in buildings Buildings account for almost 50 percent of the energy consumed in developed countries. There is increased focus on legislation and policies to improve their energy efficiency. Initiatives such as the environmental building rating system (LEED®) in the US and the UK’Building Research Establishment Environmental Assessment Method (BREEAM) are helping to transform the added-value glazing market. Both are increasingly being used to rate the environmental performance of buildings across the globe. Buildings account for almost 50 percent of the energy consumed in developed countries. Our products have a beneficial role to play in addressing some of the major environmental challenges of buildings, new and old. Similar opportunities are anticipated in Europe, with the recast of the EU Directive on Energy Performance of Buildings and a new Energy Efficiency Directive. Many other countries have indicated significant changes to national building regulations to improve the energy efficiency of new and existing buildings. We work with relevant stakeholders in framing policies and regulations that help make buildings more energy-efficient through the use of glass.

 Thermal insulation — keeping heat in buildings In cold weather, low-emissivity (low-e) products reflect heat back into the building.. They provide thermal insulation and passive solar heat gain, helping to meet demand for more energy-efficient windows. Advances in low-emissivity (low-e) glass technology have made windows an essential contributor to energy conservation and comfort, minimizing heat loss and internal condensation. Thermal insulating glass for windows and facades, also known as "low-E" (for low-emissivity) glass, usually forms the inner pane of an insulating glass unit (IGU). A transparent metallic coating reflects heat back into the room rather than allowing it to escape through the windows. At the same time, low-E glass allows solar heat to pass into a building and warm the interior (this is known as "passive solar heat gain"). Thermally insulating glass can be one of several desirable properties such as maintenance, solar control, noise reduction, decorative glass and enhanced safety and security.

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Solar control Solar control glass is glass designed to reduce or prevent solar heating of buildings. There are two approaches that can be used: the glass is either tinted (coloured) throughout the material (called a "body tint"), or else it has a microscopically thin and transparent coating on one side. In the body tint approach, the colour causes the glass to absorb solar energy, which is then reradiated back out and away from the building. Coated glasses immediately reflect the heat away.These technologies reduce the solar heating that tends to take place in large buildings, and thus reduce the need for air conditioning. It is therefore an energy-saving technology. In dwellings, it helps prevent uncomfortable overheating in conservatories and other rooms with large areas of glazing, and it can also reduce irritating glare from direct sunlight. Solar control glass can be combined with many other features for multifunctional glazing, such as thermal insulation, self-cleaning, noise reduction, decorative glass and enhanced safety and security. 

Safety and security To improve its resistance to impact and breakage, glass can be either toughened or laminated, depending on where and how it is being used. Toughened glass offers a distinct safety advantage, not only being less likely to break but also, when it does break, producing very small fragments that are relatively harmless. Laminated glass can be made so strong that it is practically impossible to break, making it feasible to use glass wherever desired, even where high security requirements apply, including bullet-resistant applications. In the case of breakage, fragments adhere to the flexible "interlayer" between glass layers, reducing the chance of injuries. These features can be combined with other glass functions for additional comfort: thermal insulation, solar control, acoustic insulation, low-maintenance and decorative glass.

 Fire resistance
A range of fire-resistant glass types is available that offers increasing levels of protection, which is measured in defined time periods (30, 60, 90, 120, 180 minutes). Fireresistant glass must meet strict levels of integrity and insulation, or integrity only which are set down by European CE standards. Fire-resistant glass must always be specified as part of a tested and approved glazing system and installed by specialists to be sure of reaching expected fire performance, if required.

 Noise control
Acoustically insulating glazing can be a major contributor to comfort levels in buildings and houses. Its benefits are greatest for people living or working near busy high streets, urban traffic, motorways, railway lines and airport.