Remembering 26/11: What we CAN do

A year after the country faced one of the worst attacks in recent history, the memory of that disastrous day continues to make us shudder. Nothing can heal the wounds that tore apart the very soul of the country and took so many innocent lives. While the best we can do for the departed souls is to say a silent prayer in their memory, there is a lot more that can be done to ensure better control in the event of a similar attack in future.

Quite evidently, the biggest threat to any building, be it a dwelling or a commercial setup, is from fire. Not less than seven explosions rocked the Taj Mahal Hotel and the Oberoi Trident at Mumbai on that fateful day that was 26th November 2008. The fire at the Mumbai hotels spread fast due to heavily furnished rooms, posing the biggest challenge. Most of the carpets, curtains, furniture, runners and suspenders used for the false ceiling were made of combustible material. One way to combat this problem is to treat these articles with fire-retardant materials. Another way is to altogether block the fire from entering the building interiors. Concrete walls, though indispensable to buildings, may not provide every kind of protection for complete safety. Often, a second cladding on the inside of a concrete wall can provide double protection.

A more recent incident that reinforced the importance of fire safety is the fire that burned down the IOC terminal at Jaipur on 29th October this year. This fire was an unstoppable force of nature; more than 30 industrial units were completely destroyed and several lives lost.

A startling observation I made from media reports on this disaster was the impact on neighbouring buildings that remained physically untouched by the fire - the glass on the windows and facades of these buildings were damaged beyond redemption. I discovered (through research fuelled by curiosity) that one of the by-products of fire is radiant heat – an invisible killer that can be just as dangerous as the fire itself. It was this very radiant heat that damaged the glass on these buildings. Radiant heat is invisible and comprises extremely intense electromagnetic waves that travel at the speed of light. On striking an object, these waves are absorbed and their energy is converted into heat. Combustible objects like paper and wood auto-ignite due to the heat when they reach their flash point.

I further discovered that had the glass on these neighbouring buildings been of a certain “tempered” variety, it would have disintegrated into small harmless pebble-like pieces which do not hurt. An even better measure would have been to install “fire-resistant glass” on these buildings. This is often done for structures that are located close to fire disaster-prone setups such as oil plants. The IOC structures could also have been insulated with this fire-resistant glass, in which case the radiant heat from the fire might not have been felt on the outside at all! The presence of such fire-resistant claddings within the buildings could have bought for its occupants, sufficient time to save their lives.

This kind of glass offers fire resistance of varying degrees, depending on the requirement. There is a kind that cuts off the fire itself along with the smoke, and another that also stops the penetration of the equally deadly radiant heat that emanates from the fire. The protection offered by these varieties of fire-resistant glass are usually categorised into “Integrity”, “Integrity and Radiation Control”, and “Integrity and Insulation”.

You can read more about this by visiting this site:

http://in.saint-gobain-glass.com/b2c/default.asp?nav1=pr&nav2=single%20pane&id=27452

There is a very interesting downloadable document that explains precisely how fire resistance works, what are the myths and realities associated with it, and how best to make your choice.

Also, gone are the days when bullet or fire proofing meant a compromise on visual appeal. Now that there is a genre of glass that can provide protection from bullets and even fire, it can be used for aesthetic enhancement and blended in perfectly with the architectural theme, providing the best in aesthetics as well as safety. And no matter what it might cost, it will be a small price to pay for safety.

I’ll sum up by saying that while there is no fool-proof way of protecting oneself from natural or man-made calamities - like the one that happened this day last year, we need to do our bit and adopt every kind of safety measure that is available to us. Luck usually has nothing to do with safety, and besides, why be sorry again when you can be safe instead.

Acid-Etched Glass

Acid etching is a process that uses a strong acid to cut into another substance. It is used for both industrial and artistic purposes. For example, etching can be used to prepare flooring like cement for painting or refinishing, while artists use it to create detailed pictures on metal or glass.

Acid-etched glass has a distinctive, uniformly smooth and satin-like appearance. Acid-etched glass admits light while providing softening and vision control.

Origin of Acid-etched glass

During the middle ages, acid glass-etching was somehow clouded with controversy since its acid medium, hydrofluoric acid, caused too much of a health risk to the artisans. In fact the acid was so potent that users were found to have been poisoned even by its mere fumes. Accidents most often happened where a skin contact with the acid dissolved into the tissues, which later resulted in mutilation or loss of the artisan’s fingers. As a result, acid etched glass craftsmanship lacked refinement and thus lost its luster as an art collection.

Now, there are etching tools such as swivel knives, pick knives, adhesive masks aside from the squeegee which makes it possible for an ordinary person to work on acid glass-etching.

Acid-Etching Glass production

Acid etched glass is produced by acid etching one side of float glass. Etched glass is created by cutting a design stencil that is made of an abrasive resistant material, such as vinyl or rubber. The resulting stencil is called a resist. The resist is then secured onto the glass to be etched. A blaster gun, powered by an air compressor, is used to bombard the glass with the abrasive. Every part of the glass that is not covered by the resist will take the frosted effect while the parts protected by the resist will remain clear, thus producing a piece of etched glass.

Etching glass - Hydrofluoric acid

Glass is etched by hydrofluoric acid, or by hydrofluoric acid gas. The gaseous acid has the property of producing a surface which resembles ground glass in its appearance; the liquid acid produces clear etching. Etching glass, therefore, consists of 2 distinct branches. First, the production of a dull image on a clear surface (when the gas is used) and second, the production of a clear image on a surface previously ground or dulled by means of the liquid acid.

The glass plate to be etched is cleaned and gently warmed until hot enough to melt wax. The surface is then covered with an equable layer of white wax, by rubbing the wax over it. When cold, the design is cut out of the wax with a graver. A shallow leaden trough, about the size of the plate (but a trifle smaller) is obtained, into which is placed a small quantity of finely - powdered fluorspar. This must be weighed and then gently sifted over the bottom of the trough. To every 2 parts by weight of fluorspar add 3 of good oil of vitriol. Stir quickly with a wooden stick, and place on the hob or other warm place. Vapour will soon rise.

Now the trough is removed and covered over with the waxed and graved plate, wax side downwards. In a very short time, the acid will have etched the bare portions of the glass. When sufficiently etched, remove the wax by melting. To prepare the liquid acid for clear etching, place 2 parts fluorspar and 3 of sulphuric acid in a leaden retort, the tube of which must dip into a leaden bottle half - filled with water.

Apply heat to the retort as long as the water will absorb the fames generated. If a ground glass be prepared with wax, as above, and a ledge of wax or putty be made round it, on pouring the liquid acid on the plate, clear lines on the dull ground will result; or a "flashed" colored glass may, by the same means, a colorless picture on a colored ground can be done. The sheets of clear glass may themselves be dulled by exposing them, without previously waxing, to the fumes of the acid gas.

Applications

Acid etched glass is perfect for both interior and exterior applications. Architecture and construction, like in houses, restaurants, hotels, commercial buildings, etc. They are found in many residential applications such as home decoration like furniture components. Some of the suggested applications are:

• Interior partitions
• Railings
• Shelves
• Shower and bath enclosures
• Doors and windows
• Glass walls
• Kitchens
• Interior and exterior doors

Etched Glass

Decorative glass of the nineteenth and twentieth centuries was sometimes put through a process of ‘etching’ to produce a frosted pattern. Etched glass is the result of intentional and often artistic carving of the surface of glass to leave a white, frosted finish. This technique is used to create designs on the glass.

Etching refers to the technique of creating art on the surface of glass by applying acidic, caustic, or abrasive substances. Etched glass can be found in a wide variety of decorative contexts, including glass doors and windows, furniture, wine bottles, and serving dishes. The skill of the artisan etching the glass will determine the quality and detail of the resulting piece.

There are three ways to create a piece of etched glass:

1. Sand-blasting
2. Acid-etching
3. Chemical etching

Sandblasting

Sandblasting is the act of shooting an abrasive material, such as sand, at a piece of glass. There are three other types of sandblasting techniques: Carving, shading, and surface etching. A combination of all three techniques can also used.

Acid etching

Acid etching uses an acid resistant material to cover areas of the glass that the artist wants protected. Hydrofluoric acid is then applied to the glass to produce the design.

Chemical etching

Chemical etching is another way to produce etched glass and is normally what is found in glass etching kits. Just as in sandblasting, a stencil is used to protect the glass where the etching effect is not desired. Instead of an abrasive, however, a chemical cream is applied to the glass. It is this etching cream that produces the final frosted effect.

Acid etching can create the same appearance as sandblasted glass. One of the major advantages of acid etching over sand blasting is that it can be done simply and without as many tools. A frosting effect can also be achieved using different strengths of acid etching compounds.

Body-tinted Glass

Body-tinted glass is normal float glass into whose melt colorants are added for tinting and solar-radiation absorption properties. This tinted glass saves energy and reduces heat penetration into buildings and gives a striking visual effect. Coloured glass is an important architectural element for the exterior appearance of façades.

Tinted glass refers to any glass that has been treated with a material such as a film or coating, which reduces its ability to transmit light. Glass can be tinted with various types of coating, which block and/or reflect different amounts and types of light, according to the needs and preferences of the consumer. Glare reduction is another important property of tinted glass. Glare

The production process of body-tinted glass is similar to that of float glass. The only variation is in the colorants mixed at the beginning with the standard raw materials. Body-tinted glass is produced when colorants and iron are introduced during the glass manufacturing process. Different additives may produce differently coloured glasses. Bronze, dark grey and green are the commonly used tints.

The end product does not affect the basic structure of the glass itself, but does enhance its performance in relation to the (solar) electromagnetic spectrum. The colour is homogenous throughout the thickness of the glass. The solar energy transmission, shading coefficient and visible light passing through the tinted glass will vary according to the colour selected.

During the float glass melt process, chemical colorants can be added which tint the colour and increase absorption from the sun. This helps minimize the solar radiation that enters a building, keeping it cool from the inside and protecting furniture from fading. As an example of the colorants used - to create a purple exterior, manganese is added, while pinks and reds can be produced from selenium.

Colorants and colors

Some of the most-used colorants and the colours they produce are listed below:

Iron – Green, brown, blue
Manganese – Purple
Chromium – Green, yellow, pink
Vanadium – Green, blue, grey
Copper – blue, green, red
Cobalt – blue, green, pink
Nickel – yellow, purple
Titanium – purple, brown
Cerium – yellow
Selenium – pink, red
Gold – Red
Cadmium-Sulphide – yellow
Carbon & Sulphur – amber, brown

Double-Glazed with High-Performance Tinted Glass

Tinted Glass is intended for universal application. Either as single or double glazing for a basic level of solar control, and even in furniture, interior design, partitions, etc. It is also the base glass for many high performance comfort glasses.

Doubly-glazed tinted glass reduces solar heat gain to below that of bronze or gray tint but has a visible transmittance closer to clear glass. High-performance or spectrally selective tinted glass products are typically light green or light blue. The tint has no effect on the U-factor but reduces solar heat gain. Doubly glazed tinted glass allows 51 percent of solar heat gain and 69 percent transmission of visible light.

Advantages

• Saves energy, controls solar heat and gives a striking visual effect
• Meets the increasing demands for light in workplaces, creates attractive interiors and gives a feeling of spaciousness
• Offers a practical, stylish alternative to traditional materials when used in screens, partitions and furniture at home or in the office
• Gives designers the freedom to create attractive modern environments that are also economical and easy to maintain
  

Body tinted glass gives the added benefit of making a building look unique and contemporary, creating a lasting impression for business HQs.
Applications

The range of available thicknesses enable glass to be used where superior strength, greater spans, reduced deflection, higher daylight transmission and enhanced noise suppression are required.

Automobiles

One of the most common applications of tinted glass is in automobile windows. Almost all cars come with tinting at the top of the windshield to reduce solar glare when the sun is low in the sky. Apart from this, the windows of several cars are tinted either at the factory or as an aftermarket add-on by the consumer, to provide privacy to the car’s occupants, as also to reduce the build-up of heat in a car while it is parked outdoors.

Dwellings

Another popular use of tinted glass is in windows of homes and commercial buildings. Residential glass tinting is much easier to do than automotive tinting. It can even be done by the homeowner himself, with some practice. Tinted glass in homes serves many practical purposes, such as limiting ultraviolet light transmission through windows, and reducing overall heat gain inside the home by reflecting solar heat energy, thereby saving the homeowner money on air-conditioning.

Commercial Buildings

Tinted glass is also used in commercial buildings. Apart from keeping the interiors cooler, it gives the outside of a building a more uniform, aesthetically pleasing appearance. Depending on the creative use of different colours of tinted glass, the building can also take on a unique and interesting appearance while being insulated from the sun at the same time.

Self-cleaning glass

Self-cleaning glass is a specific type of glass with a surface which keeps itself free of dirt and grime through photocatalytic decomposition. A nanometer-scale coating of titanium dioxide on the outer surface of the glass introduces two mechanisms which give it the self-cleaning property. Harsh chemicals that are used to clean normal glass are usually washed off into the soil and contaminate it. The use of self cleaning glass eliminates this environmental hazard.

Dual Process

Self cleaning glass cleans itself in two stages. The first stage is called photo-catalysis which is the action of light on the surface of the glass to basically chomp away or eat the dirt on the surface. The next is a process known as hydrophilicity. This basically ensures that any water that falls on the surface forms sheets and washes away dirt uniformly. The glass spreads the water evenly over its surface, without forming droplets.

Working process of the Self Cleaning Glass


Self Cleaning Glass has a coating of titanium dioxide on its outer surface. Titanium dioxide is an inorganic pigment which is widely used in a several products: everything from sunscreen where it reflects away some of the sun’s UV rays through to toothpaste through to the whitener responsible for the white colour in white paint or even in paper.

Titanium dioxide is present as a very thin coating on the outside surface of the glass. It has a thickness of about 25mm. The action of sunlight on the titanium dioxide generates a species known as electrons and holes. These electrons and holes, along with a specific property of titanium dioxide migrate to the surface and start a process known as oxidation of any organic material which is present. Effectively, the titanium dioxide absorbs the UV component of sunlight and causes the degradation and break-down of any organic material, dust or debris which are on the surface of the glass - It converts them into carbon dioxide and water. One of the best features of this is that it works on the bottom of the dirt outwards and so loosens the dirt on the material coating by destroying the contact layer of the dirt and the glass.

Any rain water impacting the surface will form a very smooth sheet which washes down foreign particles uniformly. This happens through the action of sunlight on titanium that produces a surface which is highly hydrophilic, or water-loving. Water loves wetting the surface and the action of sunlight generates hydroxyl species on the surface effectively.

Everything that settles on self cleaning glass is washed down at the same rate, but this property primarily works on surfaces which have some form of slant. If the surface is perfectly horizontal then it would struggle because of a lack of gradient for the water to run off.
Only a small amount of sunlight is required to activate the coating, which ensures that self-cleaning property will function even on cloudy days. A simple rinse with water during dry spells will help keep the surface clean.

Performance

The performance of self-cleaning glass can vary depending on the environment and the location of the glass. The other factors in play are:

1. The type of dirt
2. The amount of dirt
3. Total exposure to light and rain
4. The incline of the installation

Optimum performance is obtained when the glass is installed in a vertical position, and receives maximum exposure to direct sunshine and rain.

Applications

Self cleaning glass is very effective in highly polluted areas. The areas of its application are as follows:
• Glazed facades, exterior shop fronts, display windows, overhead & atria glazing
• Conservatories, balconies, overhead glazing
• Windows & patio doors

Advantages

1. Less frequent cleaning – facade stays cleaner for longer
2. Much easier cleaning - less dirt and grime adheres to the glass
3. Save money - the cost of facade cleaning is reduced
4. Clear vision through the facade - even when it is raining
5. Neutrality and transparency is the same as that of normal glass
6. Less frequent use of detergents – saves the environment.

Bullet Proof Glass

Bullet proof glass or bullet resistant glass refers to any type of glass that is built to stand up against being penetrated by bullets. Although the public uses the term ‘bullet proof glass’, generally within the industry itself it is referred to as bullet-resistant glass, because there is no feasible way to create consumer-level glass that can truly be proof against bullets.

Bullet proof glass is usually constructed using a strong but transparent material such as polycarbonate thermoplastic or by using layers of laminated glass. The desired result is a material with an appearance and light-transmitting behavior of standard glass but offers varying degrees of protection from small arms fire.

The polycarbonate layer, usually consisting of products such as Armormax, Makroclear, Cyrolon, Lexan or Tuffak, is often sandwiched between layers of regular glass. The use of plastic in the laminate provides impact-resistance, such as physical assault with a hammer, an axe, etc. The plastic provides little in the way of bullet-resistance. The glass, which is much harder than plastic, flattens the bullet and thereby prevents penetration. This type of bullet proof glass is usually 70–75 mm (2.8–3.0 in) thick.

Bullet proof glass constructed of laminated glass layers is built from glass sheets bonded together with polyvinyl butyral, polyurethane or ethylene-vinyl acetate. This type of bullet proof glass has been in regular use on combat vehicles since World War II; it is typically about 100–120 mm (3.9–4.7 in) thick and is usually extremely heavy.

Working Principle of the Bullet Resistant Glass

In the bullet proof glass, the Laminate-layers of tough plastic called polycarbonate sandwiched in between the pieces of toughened glass make the glass ten times thicker than the ordinary glass and it is very heavy. If someone fires a bullet at an ordinary piece of glass, the glass can't bend and absorb the energy. So the glass shatters and the bullet carries on through with hardly any loss of momentum. That's why ordinary glass offers no protection against bullets.

But when a bullet strikes bullet proof glass, its energy spreads out sideways through the layers. Because the energy is divided between a number of different pieces of glass and plastic, and spread over a large area, it is quickly absorbed. The bullet slows down so much that it no longer has enough energy to pierce through—or to do much damage if it does so. Although the glass panes do break, the plastic layers stop them flying apart.

Advances in bullet resistant glass have led to the invention of one-way bullet resistant glass, such as used in some bank armored cars. This glass will resist incoming small arms fire striking the outside of the glass, but will allow those on the other side of the glass, such as guards firing from inside the armored car, to fire through the glass at the exterior threat.

One-way Bullet Proof Glass

One-way bullet proof glass is usually made up of two layers, a brittle layer on the outside and a flexible one on the inside. When a bullet is fired from the outside it hits the brittle layer first, shattering an area of it. This shattering absorbs some of the bullet's kinetic energy, and spreads it on a larger area. When the slowed bullet hits the flexible layer, it is stopped. However, when a bullet is fired from the inside, it hits the flexible layer first. The bullet penetrates the flexible layer because its energy is focused on a smaller area; the brittle layer then shatters outward due to the flexing of the inner layer and does not hinder the bullet's progress.

Advancement

The field of bullet proof glass is constantly developing, and there are a number of military projects underway to create lighter-weight, more defensive forms of bullet proof glass. One of the most promising is the use of aluminum oxynitride in the outer layer, in place of a polymer layer.

U.S. military researchers are moving quickly to develop this new class of transparent armour incorporating aluminium oxynitride (Trade name: ALON) as the outside "strike plate" layer. It performs much better than traditional glass/polymer laminates. Aluminium oxynitride "glass" can't defeat threats like the .50 caliber armor piercing rounds using material that is not prohibitively heavy. This more resistant-glass that can be used in military assault vehicles and aircraft.

Applications

Bullet Resistant glasses have a wide range of applications as follows:

• Banks
• Government Buildings
• Convenience Stores
• Churches
• Schools
• Check Cashing Stores
• Liquor Stores
• Post Offices
• Jewelry Stores
• Art Galleries

Glass Types

Flat Glass

Flat glass is the basic material that goes into all types of glass that we see (and see through) every day: All flat glass is made in the form of flat sheets. But some of it, such as that used in automobile windshields, is reheated and sagged (curved) over moulds. It is used to make windscreens and windows for automobiles and transport, and windows and façades for houses and buildings. It is also used, in much smaller quantities, for many other applications like interior fittings and decoration, furniture, "street furniture" (like for bus stops), appliances and electronics, solar energy equipment, and others.

Annealed glass

Annealed glass is the basic flat glass product that is the first result of the float process. It is the common glass that tends to break into large, jagged shards. It is used in some end products -- often in double-glazed windows, for example. It is also the starting material that is turned into more advanced products through further processing such as laminating, toughening, coating, etc.

Laminated Glass

Laminated glass is made of two or more layers of glass with one or more "interlayer’s" of polymeric material bonded between the glass layers. Laminated glass is produced using one of two methods:

1. Poly Vinyl Butyral (PVB) laminated glass is produced using heat and pressure to sandwich a thin layer of PVB between layers of glass. On occasion, other polymers such as Ethyl Vinyl Acetate (EVA) or Polyurethane (PU) are used. This is the most common method.
2. For special applications, Cast in Place (CIP) laminated glass is made by pouring a resin into the space between two sheets of glass that are held parallel and very close to each other.
   

Laminated glass offers many advantages. Safety and security are the best-known of these -- rather than shattering on impact, laminated glass is held together by the interlayer, reducing the safety hazard associated with shattered glass fragments, as well as, to some degree, the security risks associated with easy penetration. But the interlayer also provides a way to apply several other technologies and benefits, such as coloring, sound dampening, resistance to fire, ultraviolet filtering, and other technologies that can be embedded in or with the interlayer.
Laminated glass is used extensively in building and housing products and in the automotive and transport industries.

Alarm Glass

This is a special laminated glass designed and manufactured for security purposes. The inter-layer is embedded with a very thin wire and then “sandwiched” between two or more sheets of glass. The wire forms an electrical circuit which activates an alarm when the glass is forced.

Reflective Glass

Reflective Glass is an ordinary float glass with a metallic coating to reduce solar heat. This special metallic coating also produces a mirror effect, preventing the subject from seeing through the glass. It is mainly used in façades. Reflective glasses are mainly manufactured by two different process such as Production Pyrolitic (On-Line) and Vacuum (magnetron) Process (off-line).

Anti-reflective Glass

This is float glass with a specially-designed coating which reflects a very low percentage of light. It offers maximum transparency and optical clarity, allowing optimum viewing through the glass at all times. The clarity of vision makes anti-reflective glass suitable for all applications where glass should be transparent such as exteriors, shop-fronts, commercial frontages and glazing where vision is important, particularly at nighttime. This glass can also be used in interiors for high quality picture framing, display cabinets, interior display windows and dividing screens.

Fire-resistant Glass

This can be classified into two categories:

1. Heat-transmitting Glass: Heat-resistant glass is high in silica and usually contains boric oxide. It expands little when heated, so it can withstand great temperature changes without cracking. This contains flames and inflammable gas for a short period of time but does not prevent the transmission of heat to the other side of the glazing. These include wired glass and reinforced laminated glass. This type of glasses is widely used in cookware and other household equipment, and in many types of industrial gear.
2. Fire-insulating Glass: This contains flames and inflammable gas for a longer period of time and prevents not only the transmission of flames and smoke, but also of heat to the other side of glazing

Tempered (toughened) Glass

Toughened glass is made from annealed glass treated with a thermal tempering process. A sheet of annealed glass is heated to above its "annealing point" of 600 °C; its surfaces are then rapidly cooled while the inner portion of the glass remains hotter. The different cooling rates between the surface and the inside of the glass produces different physical properties, resulting in compressive stresses in the surface balanced by tensile stresses in the body of the glass.
These counteracting stresses give toughened glass its increased mechanical resistance to breakage, and are also, when it does break, what cause it to produce regular, small, typically square fragments rather than long, dangerous shards that are far more likely to lead to injuries. Toughened glass also has an increased resistance to breakage as a result of stresses caused by different temperatures within a pane.

This type of glass is mainly intended for glass façades, sliding doors, building entrances, bath and shower enclosures and other purposes that require superior strength and safety.

Low-emission Glass

Glass that has a low-emissivity coating applied to it in order to control heat transfer through windows. Windows manufactured with low-E coatings typically cost about 10–15% more than regular windows, but they reduce energy loss by as much as 30–50%.

A low-E coating is a microscopically thin, virtually invisible, metal or metallic oxide layer deposited directly on the surface of one or more of the panes of glass. The low-E coating reduces the infrared radiation from a warm pane of glass to a cooler pane, thereby lowering the U-factor of the window. Different types of low-E coatings have been designed to allow for high solar gain, moderate solar gain, or low solar gain. A low-E coating can also reduce a window's visible transmittance unless you use one that's spectrally selective.

Window manufacturers apply low-E coatings in either soft or hard coats. Soft low-E coatings degrade when exposed to air and moisture, are easily damaged, and have a limited shelf life. Therefore, manufacturers carefully apply them in insulated multiple-pane windows. Hard low-E coatings, on the other hand, are more durable and can be used in add-on (retrofit) applications. The energy performance of hard-coat, low-E films is slightly poorer than that of soft-coat films.

Self-cleaning glass

Self-cleaning glass is a specific type of glass with a surface which keeps itself free of dirt and grime through natural processes. The first self-cleaning glass was based on a thin film titanium dioxide coating. The glass cleans itself in two stages.

The "photo catalytic" stage of the process breaks down the organic dirt on the glass using ultraviolet light (reflected from the glass)even on overcast days and makes the glass hydrophilic (normally glass is hydrophobic). During the following "hydrophilic" stage rain washes away the dirt, leaving almost no streaks, because hydrophilic glass spreads the water evenly over its surface.

Bullet-proof glass

Bullet-proof glass is thick, multilayer laminated glass. This glass can stop even heavy-caliber bullets at close range. Bullet-resisting glass is heavy enough to absorb the energy of the bullet, and the several plastic layers hold the shattered fragments together. Such glass is used in bank teller windows and in windshields for military tanks, aircraft, and special automobiles.

Body-tinted glass

Body-tinted glass is a normal float-clear glass into whose melt colorants are added for tinting and solar-radiation absorption properties. This reduces heat penetration in buildings. Coloured glass is an important architectural element for the exterior appearance of façades. Body-tinted Glass is also used in interior decoration.

Production is the same as in float glass production. The only variation is the colorants mixed at the beginning with the standard raw materials. Different additives may produce differently colored glasses.

Sand Blasted Glass

This is produced by spraying sand at high velocities over the surface of the glass. This gives the glass a translucent surface, which is usually rougher than that obtained by etching. During sandblasting, only the areas that are to remain transparent are masked for protection. The depth and degree of the translucency of the sand-blasted finishing vary with the force and type of sand used. Sand-blasted glass can be used in numerous interior design applications in both residential and commercial settings: doors, shower screens, partitions and interior screens, furniture, etc.

Acid-etched Glass

It is produced by acid etching one side of float glass. Acid-etched glass has a distinctive, uniformly smooth and satin-like appearance. Acid-etched glass admits light while providing softening and vision control. It can be used in both residential and commercial settings (doors, shower screens, furniture, wall paneling, etc.).

Wire glass

Wired glass is a product in which a wire mesh has been inserted during production. It has an impact resistance similar to that of normal glass, but in case of breakage, the mesh retains the pieces of glass. This product is traditionally accepted as low-cost fire glass. In the production of wire glass, a steel wire mesh is sandwiched between two separate ribbons of semi-molten glass, and then passed through a pair of metal rollers which squeeze the "sandwich of glass and wire" together.

Stained glass

The term stained glass can refer to the material of colored glass or the craft of working with it. Although traditionally made in flat panels and used as windows, the creations of modern stained glass artists also include three-dimensional structures and sculpture.

"Stained glass" has been applied almost exclusively to the windows of churches, cathedrals, chapels, and other significant buildings.

Fiber glass

Fiberglass, (also called fibreglass and glass fiber), is material made from extremely fine fibers of glass. It is used as a reinforcing agent for many polymer products; the resulting composite material, properly known as fiber-reinforced polymer (FRP) or glass-reinforced plastic (GRP), is called "fiberglass" in popular usage.

Bent Glass

This is a normal glass that is curved with a special process. It can be used for external sites such as facades, shop fronts and panoramic lifts. This glass is also commonly used for internal sites for showcases, shower doors and refrigerator cabinets

Patterned Glass

This glass does not have a perfectly-smooth surface but rather has different patterns impressed on it. The most common method for producing patterned glass is to pass heated glass (usually just after it exits the furnace where it is made) between rollers whose surfaces contain the negative relief of the desired pattern(s). The depth, size and shape of the patterns largely determine the magnitude and direction of reflection. Patterned glass usually transmits only slightly less light than clear glass. It can be used for a variety of applications such as interior design and decorations, furniture, windows and street furniture.

Enamelled Glass

This is tempered or heat-strengthened glass, one face of which is covered, either partially or totally, with mineral pigments. In addition to its decorative function, enameled glass is also a solar ray controller. Enamelled glass is used for glazing and for cladding facades and roofs. It can be assembled into laminated glass or glazed insulation

Colored structural glass is a heavy plate glass, available in many colors. It is used in buildings as an exterior facing, and for interior walls, partitions, and tabletops.

Soda Glass

Soda Glass is the cheapest & most common glass. It is prepared by fusing soda ash, sand, limestone. It is also called soft glass. It fuses at comparatively low temperatures. The major disadvantage of using this glass is that it is brittle & breaks easily. It cracks when subjected to sudden changes of temperature. Soda glass is used for the manufacture of window glass, glass mirrors, common glassware etc. it is easily attacked by chemicals.

Hard Glass

Hard Glass is obtained by fusing potassium carbonate & limestone. It is used for making hard glass apparatus. It is more resistant to the action of acids.

Lead Crystal Glass

Lead Crystal Glass is made from potassium carbonate, lead oxide & sand. Lead glass has high refractive index. It, therefore, sparkles & is used for making expensive glass ware. The surface of lead glass objects is often cut into decorative patterns to reflect light. Cut glass show extraordinary sparkle.

Pyrex Glass

It is made by fusing a mixture of sand, lime, borax (Na2B4O7.10H2O) & alkali carbonates. It has good chemical laboratory apparatus, ampoules, pharmaceutical containers, etc. In home, it is familiar with oven ware.

Optical Glass

It is specially made so as to be free of strains & defects. It is used for making lenses for spectacles, microscopes, cameras, telescopes & other optical instruments.

Colored Structural Glass

Colored structural glass is a heavy plate glass, available in many colors. It is used in buildings as an exterior facing, and for interior walls, partitions, and tabletops.

Opal glass

Opal glass has small particles in the body of the glass that disperse the light passing through it, making the glass appear milky. The ingredients necessary to produce opal glass include fluorides (chemical compounds containing fluorine). This glass is widely used in lighting fixtures and for tableware.

Foam glass

Foam glass, when it is cut, looks like a black honeycomb. It is filled with many tiny cells of gas. Each cell is surrounded and sealed off from the others by thin walls of glass. Foam glass is so light that it floats on water. It is widely used as a heat insulator in buildings, on steam pipes, and on chemical equipment. Foam glass can be cut into various shapes with a saw.

Photochromic glass

Photochromic glass darkens when exposed to ultraviolet rays and clears up when the rays are removed. Photochromic glass is used for windows, sunglasses, and instrument controls.