Smart Glass

In recent years, the market for light-controlSmart Glass has expanded due to the increasing demands for energy efficiency and heat and light control, automated shading, privacy, and design and engineering innovation.

Smart Glass or Switchable Glass is a product of cutting-edge technology that allows users to block either all light or just some by simply turning a knob or pressing a button. This type of light control could potentially save tremendously on heating, cooling and lighting costs.

Smart Glass technology basically means controlling the transmission of light through glass by using electrical power. By applying a variable voltage to the glass, the amount of transmitted light can be controlled. Switching speed and the consistency of a tint change are among the most important attributes to potential users of smart glass technology.

The processing technique of Smart Glass is to combine Smart Film with glass through a certain process to ensure reliable use.

Why it is so called?

When a product is called “smart”, it simply means it is programmed with an auto-intelligence capable of operating a single task. And the same goes for smart glass: instead of relying on glass treatments to block the light, these specially designed, energy-efficient glass panes automatically control the sun's solar penetration.

How does Smart Glass Work?

Switchable glass panes dim and brighten at will. When you want sun to shine through your windows, simply flip a switch to turn off the tint. You want to open a room, another flip and the windows will blur, become opaque, or slowly darken. Though they all perform the same task, there are several types of smart glass available. One of the original forms is photo chromatic technology which doesn't require manual operation. Similar to sunglasses, these panes immediately tint when the sun hits, which is efficient since they don't call for any electricity or hands-on direction.

Smart glass technologies include electrochromic devices, suspended particle devices and liquid crystal devices

1. Suspended Particle Devices

Suspended Particle Devices are constructed with two panes of glass separated by a conductive film with suspended, light absorbing, microscopic particles. These microscopic particles within the Suspended Particle Devices (SPD) absorb light, thus preventing it from passing through the film. When the electrical current is added to the film, the particles align themselves to allow light through the glass. The switchable system consists of a non-toxic film between two panes of glass - the higher the current, the more arranged the particles are, and consequently more light is allowed through the glass or plastic.

When the current is switched off, the particles are scattered, inhibiting light penetration. SPD films, which operate off an AC voltage or battery power, consume a very minute power of 0.05 watts/square feet maximum. Users can instantly and precisely control the transparency of the window by manually adjusting a dial connected to a rheostat or automatically setting the opaqueness by programming a photocell.

Smart glass using SPD technology takes several seconds to change from dark to clear, and tint changes are consistent regardless of panel size.

2. Liquid Crystals

Working similarly to SPD technology, these products are black and white: turn it on, they line up to permit light; turn it off, you're in the dark again. Liquid crystal smart glass changes its properties the most quickly of all—from translucent to transparent in milliseconds—and tint changes occur consistently regardless of panel size. Liquid crystal smart glass does not offer a shading benefit, but the view through the glass is blocked when in its translucent state. As such, this product is primarily used for interior needs (e.g., bathrooms) where privacy is required.

3. Electrochromic Glass

Electrochromic Glasses work in the opposite manner. When a current is supplied, they darken and when electricity is withheld they become clear. Another unique aspect of these is that they aren't so black and white. Instead they are able to create varying levels of light penetration, allowing total management of the sun's power. Sometimes it takes several minutes to change shades and typically electrochromic glass works from the outside to the center, but it also doesn't require a constant stream of electricity. Once the initial tint is achieved, no more power is needed.

The switching speed of electrochromic glass is slowest overall and varies depending upon the size of the panel (larger panels typically take many minutes to switch). The consistency of tint changes also varies, with larger panels sometimes exhibiting tint changes that begin at the glazing’s outer edges and then move inward (known as the “iris effect”).

Applications

Smart glass can be applicable in the following areas:

• Several professions and industries such as the house, the fitment and the automobile.
• In the industry of real estate/decoration, it can be applied in high-stand apartments, villas, town houses, office building and stores.
• Building walls, doors, windows and indoor separation, decorations.
• The big area of the projection wall.
• The controllable options of offices (meeting rooms, supervision rooms)
• The controllable options of public facilities (restaurants, hotels, banks, hospitals, the recreational places)
  

Applications of smart glass include building windows, doors and skylights; automobile, boat and aircraft windows; appliance windows, computer screens and cell phone screens. Its use in home and residential windows can all but eliminate the need for blinds or shades, and it fits in with the "green movement" by helping with interior heating and cooling.

Advantages

• Smart glass does not need cleaning and does not fade in the sun like cloth and plastic.
• It only requires a small amount of energy to sustain (powering several windows at once uses less electricity than a single light bulb) and electrochromic glass hardly needs any electricity at all.
• Can assist the air condition to economize energy and can obstruct ultraviolet radiation.
• Allows enough light even when opaque, tenders bright indoors.

Dynamic glazing technologies

Smart glass represents a category of glazing materials that visibly change their properties in response to a stimulus. In doing so, smart glazing in windows, doors, skylights and partitions offer varying levels of dynamic control of light, glare and heat.

1. Passive smart glass

Passive smart glass operates with no electrical interface and is typically found in small-format applications. Self-dimming eyewear that reacts to the presence of ultraviolet light is an example.

2. Active smart glass

The most exciting development in the architectural arena is active smart glass products, including those using liquid crystal, suspended particle device or electrochromic technology. Active smart glass requires an electrical stimulus to change its light-control properties, and power consumption levels are very low. The operating performance of active smart glass depends on the type being considered.

High-performing smart glass products provide unprecedented levels of advanced light-control while also making instant and dramatic design statements. Sleek and innovative, smart glass is tremendously empowering. Just as significant is its array of functional benefits (tunable shading, privacy, glare reduction and remarkable energy efficiency) that support the sustainable design goals of resource conservation and the well-being of building occupants.

Frosted glass

Frosted glass is a glass which has been rendered opaque through a process which roughens or obscures the clear surface of the glass. Frosted glass can enhance the beauty of windows, glass doors, or glass cabinets. This technique adds warmth and style to any décor.

Frosted glass or opaque glass is produced by the sandblasting or acid etching of clear sheet glass. It has the effect of rendering the glass translucent by scattering of light during transmission, thus blurring visibility while still transmitting light.

The frosted glass effect can also be achieved by the application of vinyl film, used as a sort of stencil on the glass surface. "Photo-resist” or photo-resistant film is also available, which can be produced to mask off the area surrounding a decorative design, or logo on the glass surface. A similar effect may also be accomplished with the use of canned frosted glass sprays.

Glass frosting can be accomplished on glass of any colour, and can look quite striking and distinctive. Care should be taken while working with acid to produce frosted glass. Eye and face protection should be worn when making frosted glass.

Various Frostings

A frosted appearance may be given to glass by covering it with a mixture of magnesium sulphate. When this solution dries, the magnesium sulphate crystallizes into fine needles. Another formula directs a strong solution of sodium or magnesium sulphate, applied warm, and afterwards coated with a thin solution of acacia.

A more permanent "frost" may be put on the glass by painting with white lead and oil, either smooth or in stipple effect. The use of lead acetate with oil gives a more pleasing effect, perhaps, than the plain white lead. If still greater permanency is desired, the glass may be ground by rubbing with some gritty substance.

For a temporary frosting, dip a piece of flat marble into glass cutter's sharp sand, moistened with water; rub over the glass, dipping frequently in sand and water.

If the frosting is required very fine, finish off with emery and water. Mix together a strong, hot solution of Epsom salt and a clear solution of gum arabic; apply warm. Or use a strong solution of sodium sulphate, warm, and when cool, wash with gum water. Or daub the glass with a lump of glazier's putty, carefully and uniformly, until the surface is equally covered. This is an excellent imitation of ground glass, and is not disturbed by rain or damp. The production of imitation frosting entails little expense and is of special advantage when a temporary use of the glass is desired.

Manufacturing Process

The frosted glass production requires a thorough cleaning of the glass surface before beginning the frosted glass process.

Frosted glass frosting formula is mixed with wallpaper paste, white powder paint pigment, water, and acid free PVA glue. All ingredients are mixed well, except the glue until having a pudding texture for the frosted glass project. Once this texture is achieved, a drop of glue is added so that the mixture will adhere to the glass.

The stencil should be placed on the glass, using painter's tape to secure it to the glass surface. The frosted glass mixture is applied using a stiff brush over the stencil. This is continued until all of the areas of the glass that we want to turn into frosted glass have been coated.

Applications

• To obtain visual privacy while admitting light.
• Decorative patterns may be imposed upon otherwise plain glass by using wax or other resist to retain transparent areas.
  

A sheet of frosted glass is an excellent privacy aid because it admits light without allowing people to see through it. In medical offices and bathrooms, the use of a curtain or blinds would make a room gloomy and unpleasant to be in. Frosted glass, on the other hand, keeps a room bright and friendly while still allowing people to be comfortable. People may also use frosted glass for privacy in entryways in urban areas.

Commercially produced frosted glass is usually frosted with acid etching or sandblasting. Acid etching is used to make frosted glass with a pattern. Patterned glass sometimes appears in ornamental windows, as well as in glasses, mirrors, vases, and other glassware around the house. The pattern can be simple or extensive, and it may include floral or geometric elements. Sandblasting is used to frost an entire sheet of glass, for installation in places like bathrooms and other areas where people might want privacy.

Patterned glass

Patterned glass is a kind of decorative translucent glass with embossed patterns on one or both surfaces. Pattern Glass or Decorative Glass or Rolled Glass is generally used where privacy or obscurity is desired but light transmission is still important. With the special property of decoration, patterned glass can allow light to pass through, at the same time, it can also prevent clear view. Usually it transmits only slightly less light than clear glass.

Patterned glass is not-perfectly-smooth structure with different patterns impressed on it. The depth, size and shape of the patterns largely determine the magnitude and direction of reflection.

Basically patterned glass has a pattern impressed on one side of the glass which prevents someone from seeing though it, for privacy. Pattern glass can also be ordered in various tints as well. A common application of this sort is when used in privacy walls to separate one room from another.

Rolled Pattern glasses are available in a wide variety of patterns, to add the perfect complement to many interior designs. Heavy patterned glasses provide added strength and support, and are a fast-growing product category. According to customers' requirements, patterned glass can be cut, ground, drilled, tempered, laminated, etc.

Production

Patterned glass is made with a rolled glass process. All rolled patterned glass begins as a batch of materials, including silica sand, soda, and lime. These materials are melted together in a tank, and then the molten glass mixture is fed onto a machine slab. The glass flows under a refractory gate which controls glass volume and speed then moves between two counter-rotating, water-cooled rollers. One of these rollers is embossed, imprinting a distinct pattern onto the soft surface of the glass while the other roller is smooth.

The result is a piece of glass that is patterned and textured on one side, while smooth on the reverse. The distance between the two rollers determines the ultimate thickness of the glass. After it moves between the rollers, patterned glass is annealed or cooled slowly in order to remove any residual stresses. Rolled patterned glass can then be cut into standard sizes or cut into customized sizes for a specific customer application. The glass is then inventoried and ready for delivery.

Applications

Rolled glasses are used in commercial, residential, and specialty applications. End uses include shower doors and tub enclosures including frameless shower doors interior partitions, translucent door and window treatments, foyers and vestibules, patio furniture, shelving, decorative furniture, and lighting fixtures. Comprehensive range of soft natural colours compliments and harmonizes with modern building materials to provide an exciting and different look to new and existing buildings. Pattern glasses are available in large amount of patterns. Patterned glass is most often found in bathroom windows.

Patterned glass is applied to all kinds of public and private places, such as office, meeting room, hotel, hospital, bath room, washroom, etc. It is also widely used as glass table, glass shaft and lampshade and so on. Mainly used in interior partitions, interior design, decorations, street furniture etc.

Chemically strengthened glass

Chemically strengthened glass is a type of glass that has increased strength as a result of a post-production chemical process. Chemical strengthening is the name given to glass products that have been strengthened by means of an ion-exchange process. It is a surface treatment which occurs at a temperature lower than glass melting temperature. The process is particularly useful for thin glass, tiny glass and shape glass which cannot be tempered by ordinary physical tempering.

Chemically strengthened glass is typically six to eight times the strength of float glass. In the case of breakage, chemically strengthened glass breaks into bigger pieces which are not as sharp as those of non-toughened glass. The surface compression condition which is higher in the case of a chemically strengthened glass also involves an increase of flexion resistance, which is one of the main characteristics of chemically strengthened glass.

Chemical strengthening results in a strengthening similar to toughened glass. Chemically strengthened glass has little or no bow or warp, optical distortion or strain pattern. This differs from toughened glass, in which slender pieces can be significantly bowed.

Chemically strengthened glass may be cut after strengthening, but loses its added strength within the region of approximately 20 mm of the cut. Similarly, when the surface of chemically strengthened glass is deeply scratched, this area loses its additional strength. Chemically strengthened glass retains its colour and light transmission properties after treatment.

Chemically strengthened glass offers an improved scratching, impact and bending strength, as well as an increased temperature stability.

Manufacturing process

The glass is chemically strengthened by a surface finishing process. The glass to be treated is dipped into a bath of dissolved potassium salts at a temperature about 380oC for duration from 4 to 30 hours, producing an ionic exchange between the superficial sodium ions in the glass and potassium ions inside the bath. The cycle time would be greatly reduced if the glass is made of certain elements such as lithium or magnesium because ion mobility between potassium and these elements is a lot faster. The process parameters such as ion exchanging time and temperature would be modified according to the type of glass to be treated and the required strengthen specification.

The introduction of potassium ions which are larger in size than the sodium ions results in the establishment of a system of residual stress characterized by compression stretches on the surface counterbalanced by traction stretches within the glass

Sodium ions and thus, creates stress on glass surface. During cooling, the potassium on surface shrinks little while the sodium in inner shrinks larger. Hence, stress is induced between glass surface and inside and consequently, the glass is strengthened.

Advanced process

There also exists a more advanced two-stage process for making chemically strengthened glass, in which the glass article is first immersed in a sodium nitrate bath at 450 °C, which enriches the surface with sodium ions. This leaves more sodium ions on the glass for the immersion in potassium nitrate to replace with potassium ions. In this way, the use of a sodium nitrate bath increases the potential for surface compression in the finished article.

Classifications

Chemical strengthened glass is classified by two strength components: surface compression and depth of layer (DOL). Surface compression values relate to flexural (bending) strength (MOR), impact strength, hardness penetration (scratching) and thermal shock resistance. Depth of layer values relate primarily to the amount of sustained abrasion resistance and the impact resistance of the surface compression layer.

Applications

Chemically strengthened glass was used for the aircraft canopy of some fighter aircraft. The chemically treated glass boasts a transparency range from the UV through the visible and into the infrared. This permits weapons systems designers to operate guidance devices whether they are CCD, radio frequency, infrared or laser based. The material's proponents stress that chemically treated glass is not just for use in military applications.

It can be used in numerous applications that demand toughness and optical clarity. The material is also useful for viewports, protective covers, and front surface optics in hostile environments whose elements may include high temperature, high pressure and vacuum conditions. Less demanding applications include point of sale scanner windows used in grocery store and retail scanners.

Wired Glass

Wired glass is a type of glass into which a wire mesh is embedded during production. Wired glass 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 a low-cost fire-resistant glass. Wired glass can be tinted by aerosol or electricity. Common colours are golden-yellow, green, light blue and violet-rose.

Wired glass is manufactured primarily as a fire retardant, with wire mesh inlaid in the glass to prevent it from shattering and breaking out under stress or when exposed to high temperatures. With the window intact, the glass keeps the fire at bay, protecting those on the other side from the harmful effects of smoke and flame.

However, in recent times, experts warn against the use of wired glass as a fire-resistant substance. This because although the mesh may prevent the fire from penetrating, by itself it could prove dangerous, being made of fine, sharp wires which can hurt. Today, special fire-resistant glass is available, which is devoid of the wire mesh as a component and can cut off not just the fire but even smoke, gases and deadly radiant heat.

Wired glass is made as a part of the rolled glass manufacturing process. Rolled glass is manufactured by passing molten glass from a furnace through a series of rollers to obtain the desired thickness and pattern. The rolled glass process is used to create wired glass, figured or patterned glass, and art/opalescent/cathedral glass.

Wired glass is produced by continuously feeding wire mesh from a roller into the molten glass ribbon just before it undergoes cooling. 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. Wired glass may be further processed by grinding and polishing both surfaces, producing "polished wired glass”.

Fused Glass

Fusing glass in a kiln is a fascinating technique that enables artists to create unique and breathtaking designs in glass. Fused glass is also referred to as kiln-formed glass, art glass fusion and warm glass. The “warm” of warm glass is between 1,100 and 1,700 degrees Fahrenheit (600 and 925 degrees Celsius). At these temperatures, glass softens enough that when pieces of glass are heated and pressed together, they will fuse into a single seamless piece. This is the underlying principle behind glass fusing.

Glass Fusing

Glass fusing is the process of using a kiln to join together pieces of glass. If you apply heat to glass, it will soften. If you continue to apply heat, the glass will become more fluid and flow together. Two or more pieces of glass will stick to each other. When the right kind of glass is heated and then cooled properly, the resulting fused glass piece will be solid and unbroken.

Fused glass is normally fired (heat-processed) in a kiln at a range of high temperatures from 593 °C (1,099 °F) to 816 °C (1,501 °F). There are 3 main distinctions for temperature application and the resulting effect on the glass. They are as follows:

1. Slumping

2. Tack fusing

3. Full fusing

1. Slumping

Firing in the lower ranges of these temperatures 593–677 °C (1,099–1,251 °F) is called slumping. Slumping is a categorical description of an area of techniques for the formation of glass by applying heat to the point where the glass becomes plastic. The increasing fluidity of the glass with temperature causes the glass to 'slump' into the mould under the force of gravity. Glass is most commonly heated in an oven, often using glass in a sheet form and “slumping” it over a form or into a mould.

Moulds are generally made of high temperature plaster, clay coated with plaster or another release agent, graphite, sand mixed with a bonding agent, steel, or other materials. At the point where the glass has achieved the desired form the heat is quickly vented and the temperature reduced to prevent further movement of the glass and then it is stabilized at its respective annealing temperature and annealed.

2. Tack Fusing

Tack Fusing Glass refers to the effect that is obtained when two or more pieces of glass are heated to approximately 1350 to 1375 degrees F. This temperature range will result in any pieces of glass that are in contact with each other fusing together, while still allowing each piece to retain its' original shape, size and thickness.

3. Full Fusing

Several pieces of glass fused into a single finished piece of uniform thickness by heating them to somewhere between 1450 and 1475 degrees F is known as Full fusing. At these temperatures your glass will have melted enough to combine and flow together into a single piece of fused glass. This piece may be a finished piece or a starting point from which you cold work, cut or reshape the piece prior to another fusing.

Techniques

Most contemporary fusing methods involve stacking, or layering thin sheets of glass, often using different colors to create patterns or simple images. The stack is then placed inside the kiln (which is almost always electric, but can be heated by gas or wood) and then heated through a series of ramps (rapid heating cycles) and soaks (holding the temperature at a specific point) until the separate pieces begin to bond together. The longer the kiln is held at the maximum temperature the more thoroughly the stack will fuse, eventually softening and rounding the edges of the original shape.

Once the desired effect has been achieved at the maximum desired temperature, the kiln temperature will be brought down quickly through the temperature range of 815 °C (1,499 °F) to 573 °C (1,063 °F) in order to avoid devitrification. It is then allowed to cool slowly over a specified time, soaking at specified temperature ranges which are essential to the annealing process. This prevents uneven cooling and breakage and produces a strong finished product. This cooling takes place normally for a period of 10–12 hours in 3 stages.

The first stage- the rapid cool period is meant to place the glass into the upper end of the annealing range 516 °C (961 °F). The second stage- the anneal soak at 516 °C (961 °F) is meant to equalize the temperature at the core and the surface of the glass at 516 °C (961 °F) relieving the stress between those areas. The last stage, once all areas have had time to reach a consistent temperature, is the final journey to room temperature. The kiln is slowly brought down over the course of 2 hours to 371 °C (700 °F), soaked for 2 hours at 371 °C (700 °F), down again to 260 °C (500 °F) which ends the firing schedule. The glass will remain in the unopened kiln until the pyrometer reads room temperature.

Tiffany glass

History of Tiffany Glass

Tiffany glass is the generic name used to describe the many and varied types of glass developed and produced by Louis Comfort Tiffany, (1848-1933), one of the most famous stained glass artists of the United States; he was remembered not only for his windows but for decorative glass objects as well, in particular the so-called Tiffany lamps.

Tiffany was an interior designer, and in 1878 his interest turned towards the creation of stained glass, when he opened his own studio and glass foundry because he was unable to find the types of glass that he desired in interior decoration.

Tiffany Glass

Most people think of Tiffany glass as decorative bronze lamps with intricate multicolored, stained-glass shades, but it actually includes other glass products, including solid color windows, painted art glass shades and lamps, and flat and pressed glass. Tiffany glass pieces were incorporated into homes, most notably in lamp and window construction. The glass work was used in the homes of the wealthy, but also in public buildings.

Tiffany glass not only incorporates the color into the glass, but also tonal variations and texture, as well as use tonal variations to suggest depth. The pieces of glass were not evenly colored but were pieces of opalescent window glass made by combining and manipulating several colors to create an unprecedented range of hues and three-dimensional effects. Thus the tiffany windows look like paintings, which were therefore in great demand.

The Preston Bradley Hall dome put in place in Chicago's first public library in 1897 features more than 1,000 square feet of Tiffany glass. (Preston Bradley Hall is now home to the Chicago Cultural Center.)

Types of Tiffany glass

1. Opalescent glass

Opalescent glass is commonly used to describe glass where more than one color is present, being fused during the manufacture, as against flashed glass in which two colors may be laminated, or silver stained glass where a solution of silver nitrate is superficially applied, turning red glass to orange and blue glass to green. Some opalescent glass was used by several stained glass studios in England.

Opalescent glass is made with a combination of white glass and a cathedral color. The opacity of this type of glass is in relation to the amount of white glass used in its creation. Dense opal base glass uses a higher consistency of white glass than light opal base glass. Because of this change in mixtures, dense opal base glass is much more opaque than light opal base glasses.

Opalescent glass radiates especially deep, vibrant hues to achieve pictorial effects of unsurpassed beauty. This stunning stained glass piece features transparent enamels, silk-screened and kiln-fired on hand-rolled glass.

Opalescent glass is made in a number of ways, including as a single colour; with the pigments that give the glass a streaky, mottled, or cloudy appearance; and with or without a surface texture. It can be both a most beautiful and challenging glass with which to work. This is because the pigments are mixed into opalescent glass by hand during manufacture, with the result that the color patterns and tones in the glass are never exactly the same in any two sheets.

Opalescent glass has one characteristic that transparent glass does not: namely, that it can be seen in both transmitted and reflected light. Opalescent glass has color impregnated into it to the extent that the pigmentation is visible by light rays reflecting off it. It can be seen as well as seen through.

2. Favrile Glass

Favrile glass often has a distinctive characteristic that is common in some glass from Classical antiquity: it possesses a superficial iridescence. This iridescence causes the surface to shimmer, but also causes a degree of opacity. This iridescent effect of the glass was obtained by mixing different colors of glass together while hot. Favrile is different from other iridescent glasses because its color is not just on the surface, but imbedded in the glass.

Some of the distinguishing colors in Favrile glass includes "Gold Lustre", Samian Red"," Mazarin Blue", "Tel-al-amana" (or Turquoise Blue), and Aquamarine. Favrile was the first art glass to be used in stained-glass windows, as Tiffany first thought of the idea of making patterns in windows based shapes and colors.

3. Streamer Glass

Streamer glass refers to a sheet of glass with a pattern of glass strings affixed to its surface. Tiffany made use of such textured glass to represent, for example, twigs, branches and grass.

Streamers are prepared from very hot molten glass, gathered at the end of a punty (pontil) that is rapidly swung back and forth and stretched into long, thin strings that rapidly cool and harden. These hand-stretched streamers are pressed on the molten surface of sheet glass during the rolling process, and become permanently fused.

4. Fracture Glass

Fracture glass refers to a sheet of glass with a pattern of irregularly shaped, thin glass wafers affixed to its surface. Fracture glass is made from paper-thin blown shards or flakes of intensely colored glass fused to the bottom of sheets during the rolling process. Tiffany made use of such textured glass to represent, for example, foliage seen from a distance.

The irregular glass wafers, called fractures, are prepared from very hot, colored molten glass, gathered at the end of a blowpipe. A large bubble is forcefully blown until the walls of the bubble rapidly stretch, cool and harden. The resulting glass bubble has paper-thin walls and is immediately shattered into shards. These hand blown shards are pressed on the surface of the molten glass sheet during the rolling process, to which they become permanently fused.

5. Fracture-streamer Glass

Fracture-Streamer glass is fracture glass combined with hand-stretched streamers or strings of glass during the rolling process. Fracture-streamer glass refers to a sheet of glass with a pattern of glass strings, and irregularly shaped, thin glass wafers, affixed to its surface. Tiffany made use of such textured glass to represent, for example, twigs, branches and grass, and distant foliage.

The “fractures” are created by the addition of thin blown flakes of intensely colored glass, while the “streamers” are pulled or drawn strings of intense colors. Both fractures and streamers are quick-fused to the bottom of sheets during the rolling process.

Fracture and streamer glass is used primarily for backgrounds; the fractures suggest multitudinous leaves or flowers in the distance, while the streamers suggest twigs or stems. For this reason, fracture colors are usually selected to correspond to the colors used in leaf or flower foregrounds.

6. Ripple Glass

Ripple glass refers to a sheet of textured glass with marked surface waves. The texture is created during the glass sheet-forming process. A sheet is formed from molten glass with a roller that spins on it, while travelling forward. Normally the roller spins at the same speed as its own forward motion, and the resulting sheet has a smooth surface. In the manufacture of rippled glass, the roller spins faster than its own forward motion. The rippled effect is retained as the glass cools.

In order to cut ripple glass, the sheet may be scored on the smoother side with a carbide glass cutter, and broken at the score line with breaker-grozier pliers.

7. Ring Mottle Glass

Ring mottle glass is an opalescent glass in which rates of crystal growth have been controlled to create ring-shaped areas of opacity. The effect is a visual surface mottling. Ring mottle glass refers to sheet glass with a pronounced mottle created by localized, heat-treated opacification and crystal-growth dynamics. Tiffany's distinctive style exploited glass containing a variety of motifs such as those found in ring mottle glass, and he relied minimally on painted details.

This type of glass has a locally varying opacity; the “rings” are more opaque than the surrounding matrix. Ring mottled glass is used to provide color and image gradation that is non-streaky, or non-linear. The naturally rounded shape of each ring breaks up the more typical streakiness of stained glass. The artist, using ring mottles, can create shading and imagery unavailable from other glass types.

8. Drapery Glass

Glass sheets with multiple dramatic folds, likened to those in hanging drapes. Drapery glass refers to a sheet of heavily folded glass that suggests fabric folds. Tiffany made abundant use of drapery glass in ecclesiastical stained glass windows to add a 3-dimensional effect to flowing robes and angel wings, and to imitate the natural coarseness of magnolia petals.

To create drapery glass, the molten glass is shaped by taking a hand held roller and using it like a rolling pin to create "speed bumps" on the surface. It can also be tugged and pulled by hand using steel tongs to create the deep fabric-like folds in the surface. It is easy for the glassmakers to get burnt while making this unusual glass and extreme care must be taken while rolling the glass.

Dichroic glass

‘Dichroic glass’ is really a misnomer. The dichroic part is actually a very thin film of metal oxides which are too thin to stand alone and have therefore been layered onto a sheet of glass which acts as a substrate to lend the thin film strength. Dichroic glass is any glass that is coated with metallic oxides such as silicon, titanium and magnesium in a vacuum furnace using a technology called thin-film physics. Dichroic means 'two colors' and the glass is called this because it reflects one color but transmits another.

Dichroic glass is a high-tech spin-off of the space industry. "Dichroic" is defined as the property of having more than one colour, especially when viewed from different angles or from transmitted to reflected light. Hence dichroic glass is also referred to as "chameleon glass". For example, a particular formulation will appear blue, but shift the dichroic glass slightly and the color will transition to green.

Dichroic coated glass is produced by a process called "thin film physics" and is generally referred to as a colour separator. It's normally used as an interference filter in scientific measuring or correcting applications. It is transparent, has adequate rigidity, is stable, withstands relatively high temperatures, and is not affected by moisture, solvents or most acids.

Manufacturing Process

Dichroic Glass is made by applying a surface coating of one or more layers of transparent materials designed to create reflections of a specific wavelength in order to modify an optical effect. The coating itself is completely transparent. Dichroic glass can provide very crisp and vibrant colors.

The most commonly used coating materials are titanium oxides, zirconium oxides, silicon oxides and aluminum oxides. They are applied using a method called Vapour Deposition. The deposition occurs in a high vacuum chamber where the glass is suspended in the top of the chamber and rotated. The coating materials are placed in crucibles at the bottom of the chamber and bombarded with an electron beam that is focused and swept over the materials with electromagnetic fields. The heat generated by the bombardment vaporizes the materials, and the vapour condenses on the glass suspended above.

Dichroic coatings create some of the purest and most brilliant colours ever seen in glass. They are fragile and must be protected from abrasion unless they are reheated too close to the softening point. Once heated in this way, the coating becomes very durable. The resulting colour of the glass depends on the sequence of the many layers of coatings. Incredibly, the total thickness of the multi coatings is only between 3 to 5 millionths of an inch. It is a highly technical computerized manufacturing process.

The resulting Dichroic Glass is totally unlike normal coloured glass where light enters and part of the colour spectrum is absorbed, leaving the part not absorbed to be reflected. With Dichoric Glass all light entering is either transmitted or reflected (“dichromatic" means "two-colored"). These two sources have completely different colours, and importantly, the colours alter as the angle of view is changed. This results in fascinating and beautifully vibrant colours.

With the play of light together with its vibrant colour, Dichroic Glass is a prime tool used to add interest to any piece of work or project. With over 45 colours of dichroic doatings available that can be placed on “any” substrate (i.e glass), artists have unlimited freedom of expression.

Architectural Applications

There is an ever growing demand for the use of dichroic glass in architecture. Its resilience to weather and never-fading colors are prime material to enhance office buildings, custom homes, walkways, fountains, skylights, walls, lighting fixtures and more. Dichroic glass is also used in windows and curtain walls. Dichroic glass windows on the external wall maximize the entry of natural daylight.

In Other Industries

Dichroic Glass was originally created for the aerospace industry for satellite mirrors, but it now has many technical uses including lighting, fibre optics, infrared lasers, motion picture equipment, and more.

Crown Glass

Crown glass was one of the two most commonly used types of glass for windows up until the 19th century, the other being blown plate glass. The process of making crown glass was first perfected by French glassmakers in the 1320s. Crown glass is made without lead, chiefly by fusing fixed alkali with silica sand, to which is added some black oxide of manganese – which gives the glass a tinge of purple.

For the best crown glass, the ingredients must be prepared in the same manner as for mirrors, and mixed in the following proportions: 60 lbs. of white sand, 30 lbs. of pearlash, and 15 lbs. of nitre, 1 lb. of borax, and 1/2 lb. of arsenic.

Crown Glass Making Process

A blowpipe is dipped into melted glass, which is then blown into the form of a large globular bottle. A rod tipped with a blob of hot glass is so placed that the blob or "punty" sticks to the centre of the bottom of the blown globe. Spinning the semi-molten ball then causes it to flatten and increase in size, but only up to a certain diameter.

The globe is then detached from the blowpipe, heated, and rotated vigorously until it whirls out by centrifugal force into a flat disc or "table" having a blob or "bullion" of glass in the centre.

The finished “table” of glass was thin, lustrous, highly polished (by “fire-polish”), and had concentric ripple lines, the result of spinning; crown glass was slightly convex, and in the centre of the crown was the bull’s eye - a thickened part where the pontil was attached. This was often cut out as a defect, but later it came to be prized as evidence of antiquity. Nevertheless, and despite the availability of cheaper cylinder glass (cast and rolled glass had been invented in the 17th century), crown glass was particularly popular for its superior quality and clarity.

This process allows the colour range to be limitless; crown glass is used ecclesiastically, commercially, domestically and for restoration purposes.

Burmese glass

Burmese glass was patented in 1885 by the U.S. Mount Washington Glass Company. Queen Victoria was apparently awed by the beauty of this art glass and purchased a Burmese glass tea set. Thomas Webb and Sons, a British company, were then licensed to produce their own version of Burmese glass known as Queen's Burmeseware. Queen Victoria gave permission to name the art glass collection in her honour.

In addition to being adorned in dazzling colors, Burmese glass could be crafted into a shiny surface ware or one with a dull satin-like finish. The majority of Burmese glass however was given the duller acid-induced matte finish surface which ultimately became more popular with the public. Some Burmese glass designs displayed colorful enamels with artwork such as flowers, birds or fish. Burmese glass was blown, blow moulded, and press moulded.

Burmese glass can be produced in all sorts of shapes and forms, although it is most commonly used as ornamental vases or lamps, small fairy lights, candle shades, or as decorative tabletop items. It also comes unlined, which increases its attractiveness and value. Burmese glass has a fluorescent appearance.

Manufacturing Process

The process for producing Burmese glass begins with an ordinarily translucent white glass. Addition of uranium oxide gives a warm yellow color to Burmese glass, while the high degree heating or re-heating of the gold (a tincture of which is added) imparts the rosy pink shading. Intense heat directly influences the extent of shading. The combination of all three elements in varying degrees creates a breathtaking array of colors.

Burmese glass products also came with attached glass beads, making for a brilliant glowing effect. Another technique used to create Burmese glass was called coralene. In this process, the glassworker would fasten small beads to the surface of the glass with an enamel paste. When bright light passed through the beads and reflected off of the paste, the result would be a glowing effect in the overall art glass. There were occasional instances where they would also apply gilded decorations, but for the most part, the appeal and attraction of Burmese glass lay in its elegant simplicity.

Annealed Glass

Annealed glass is glass produced without internal stresses imparted by heat treatment, i.e., rapid cooling, or by toughening or heat strengthening. Glass becomes annealed if it is heated above a transition point then allowed to cool slowly, without being quenched. Glass is treated with heat in order to change its properties by the annealing process. Annealed glass is the most common glass used in windows. Annealed glass is also known as a standard sheet of float glass.

Annealing is actually a process of slowly cooling glass to relieve internal stresses after it is formed. The glass, formerly annealed on shelves in a melting furnace, is now usually carried on rollers through temperature-controlled kiln known as a Lehr (annealing ovens). The shaped glass is annealed to relieve stresses caused by manipulation, then is slowly cooled.

Glass which has not been annealed is liable to crack or shatter when subjected to a relatively small temperature change or mechanical shock. Annealing glass is critical to its durability. If glass is not annealed, it will retain many of the thermal stresses caused by quenching and significantly decrease the overall strength of the glass.

Annealing Process



The glass is heated until the temperature reaches a stress-relief point, that is, the annealing temperature (also called annealing point) at a viscosity, η, of 1013 Poise = 1012 Pa•s, at which the glass is still too hard to deform, but soft enough for the stresses to relax. The piece is then allowed to heat-soak until its temperature is even throughout.

Soaking is a process of subjecting glass to a steady temperature. The higher the temperature the glass is soaked at, the shorter the period the glass needs to be exposed to such a temperature. Of course, glass exposed to very high temperatures requires longer time to cool down.
Caution should be taken to not expose the glass to a temperature that can adversely affect its structure. On the contrary, when glass is annealed at lower temperatures, it takes longer soaking time but requires commensurately less cooling time. The type of soak a glass should be subjected to depends on the type of glass.

The time necessary for soaking varies depending on the type of glass and its maximum thickness. The glass is then slowly cooled at a predetermined rate until its temperature is below the strain point (η = 1014.5 Poise). Following this, the temperature can safely be dropped to room temperature at a rate limited by the heat capacity, thickness, thermal conductivity, and thermal expansion coefficient of the glass. After the annealing process the material can be cut to size, drilled or polished.

At the annealing point (η = 1013 Poise) stresses relax within several minutes, while at the strain point (η = 1014.5 Poise) stresses relax within several hours.[2] Stresses that are still present below the strain point are permanent.

Float glass is annealed during the process of manufacture. However, most toughened glass is made from float glass that has been specially heat-treated. Annealed glass breaks into large, jagged shards that can cause serious injury, thus considered a hazard in architectural applications.

Care should be taken when choosing locations to install annealed glass. Building codes in many parts of the world restrict the use of annealed glass in areas where there is a high risk of breakage and injury, for example in bathrooms, indoor panels, fire exits and at low heights in schools or domestic houses.

Annealed glass has the surface strength that provides the wind-load performance and thermal-stress resistance needed in most architectural applications. In areas of high wind loads, or in conditions where higher-than-normal thermal stresses occur, heat-treated glass may be required.

Curved Annealed Glass

Curved annealed glass is used in applications that do not require the use of safety glass. This includes shop windows and display counters. Curved annealed glass can be produced for custom designs and has the advantage of being able to be cut and processed after it has been bent to its desired shape/form.

Russia Nightclub Fire: Fire Safety Lapse Claims over a Hundred Lives

The News

Russia is still coming to terms with its most deadly fire since Soviet times after 109 people died and more than 130 were injured in a blaze at a packed provincial nightclub on December 4, 2009. The fire started when a performance artist threw pyrotechniques too high and burnt the ceiling which quickly ignited the walls. The Lame Horse club, where the disaster occurred, was celebrating its eighth anniversary on the day.

One of the fireworks, tossed into the air and intended to be caught, hit the plastic covering of the ceiling, igniting the explosive. The decorative woven twigs affixed to the walls and ceiling also caught fire, filling the building with smoke. Panic gave way to a stampede when many patrons found themselves cut off from one public exit, management having sealed off other doors and the public unaware of emergency exits behind the stage.

Fire Safety: Why & How

Clearly, the Lame Horse Club owners had been callous about this aspect of safety, given that Russia’s Emergency Situations Minister Sergei Shoigu stated that the owners had been fined twice in the past for breaking fire safety regulations.

However, “Fire Safety” is not just a fancy term, and the implementation process not as complicated as is made out to be; there are some key elements of the process which can be easily adhered to.

• Building a facility in accordance with the version of the local building code

• Maintaining a facility and conducting oneself in accordance with the provisions of the fire code. This is based on the occupants and operators of the building being aware of the applicable regulations and advice.

Examples of these include:

• Not exceeding the maximum occupancy within any part of the building.

• Maintaining proper fire exits and proper exit signage (e.g., exit signs pointing to them that can function in a power failure)

• Placing and maintaining fire extinguishers in easily accessible places.

• Properly storing/using, hazardous materials that may be needed inside the building for storage or operational requirements (such as solvents in spray booths).

• Prohibiting flammable materials in certain areas of the facility.

• Periodically inspecting buildings for violations, issuing orders to comply and, potentially, prosecuting or closing buildings that are not in compliance, until the deficiencies are corrected or condemning it in extreme cases.

• Maintaining fire alarm systems for detection and warning of fire.

• Obtaining and maintaining a complete inventory of firestops.

• Ensuring that spray fireproofing remains undamaged.

• Maintaining a high level of training and awareness of occupants and users of the building to avoid obvious mistakes, such as the propping open of fire doors.

• Conducting fire drills at regular intervals throughout the year.

Practical Application



An example of how following these rules could have proved a life-saver in the Lame Horse lies in the fact that most victims died from smoke inhalation and carbon monoxide poisoning. There are fireproofing devices available that cut off not just the fire itself but even the radiant heat that emanates from it, as also the smoke and gases that are just as deadly. And in a place like a nightclub where the aesthetics imparted by tasteful and expensive interior décor is just as important as safety, fire resistant glass which offers this kind of protection is now abundantly available. Fire doors that are thoroughly tested for fire resistance and also adorn building interiors with their seemingly delicate appearance are one of the best choices for this purpose.

Also, it is important that a fire exit door opens towards the outside (persons trapped inside must be able to open the door by pushing and not pulling it). In the past, there have been cases where victims have died not because of the fire itself but thanks to a stampede caused by large numbers of people rushing towards the fire exit door at the same time, making it impossible for the door to be pulled open.

NOT an option

Russia records up to 18,000 fire deaths a year, several times the per-capita rate in the United States and other western countries; worldwide, nightclub fires have killed thousands of people. Another similar accident anywhere in the world will only establish deliberate carelessness by responsible authorities, because as is abundantly clear, fire safety is neither complicated nor expensive; not as compared to a human life anyway.

Fire Safety: Is Your Glass Fire Resistant? Another Wake-up Call

Yet another fire accident, still a lot left to chance rather than appropriate safety measures. The fire that broke out on Tuesday morning in the cafeteria of the Cognizant Technology Solutions (CTS) office at Kolkata once again drove home this point. An apparent gas leak is said to have started the fire, injuring two cooks and causing considerable damage to assets.

Police said gas that leaked from a cylinder caused the fire at around 9.40 am when one of the cooks, Chandrasekhar, was apparently pushing the cylinder below the kitchen table. Both burners of the oven had already been lit. With the regulator removed and gas leaking freely, the flames spread from the burners in a flash, injuring Chandrasekhar.

The obvious learning is that gas cylinders must never be handled carelessly. A suspended regulator is a recipe for disaster. Apart from this, measures to control and restrict fire in case it breaks out must also be taken.

Extinguishing is usually the reactive action that is deployed in case of a fire accident. But insulation could be the smarter thing to do. Different kinds of fire-resistant substances are abundantly available, but if aesthetics, visibility as well as fire security are to be taken care of, then fire-proof glass would be the ideal solution. With functionalities such as cutting out the fire itself, smoke, gases and even radiant heat, fire resistant glass has almost no equivalent substitute.

The usage of the right type of glass could be a life-saver too. For instance, fortunately wired glass (glass laced with very sharp and fine strands of steel) had not been used to glaze the kitchen exteriors. Had that been the case, rescue teams would have found it extremely difficult to enter the premises.

Be it the use of a fire-resistant glass or some other fire-retardation substance, the point is that fire safety is not an option and that we need to wake up to it, and soon.

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.