Glass is an amorphous (non-crystalline) solid material
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A glass is defined as an inorganic product of fusion which has been cooled
through its glass transition to the solid state without crystallizing
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Contains silica as their main component
INGREDIENTS:
SODA-LIME GLASS
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Silica is the major ingredient of any glass
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It has a glass melting point of over 2300 deg C
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Pure Silica glass is used for special applications
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Sodium Carbonate(in the form of soda ash) is added to lower the melting
point to around 1500 deg C
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But soda makes the glass “water soluble” which is undesirable
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Hence calcium oxide(obtained from limestone CaO),magnesium oxide and
aluminum oxide is added for the chemical stability
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The resulting glass is called “soda-lime glass”
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It contains about 70-75% of silica by weight
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Soda-lime glass accounts for about 90% of manufactured glass
COMPOSITION
There are three classes of components for oxide glasses:
1. Network formers
2. Intermediates and
3. Modifiers
PROPERTIES
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It absorbs, refracts or transmits light
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It is extremely brittle
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It has no sharp melting point
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It has no definite crystalline structure
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It is affected by alkalis.
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It is available in various colors
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It can take up a high polish and may be used as substitute for very costly
gems.
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It is an excellent electrical insulator at elevated temperatures due to the fact
that glass may be considered as an ionic liquid.
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It behaves more as a solid than most solids in the sense that it is elastic .
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It is not usually affected by air or water
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It is possible to obtain glasses with diversified properties. The glasses may be
clear, colorless, diffused and stained.
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It is possible to weld pieces of glass by fusion.
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It is transparent and translucent.
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The glass panes can be cleaned easily by any one of the following methods.
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Painting the glass panes with lime –wash and leaving it to dry and then
washing with cleaning water.
MANUFACTURING:
Broadly divided into following five stages
1. Collection of Raw Materials
2. Preparation of Batch
3. Melting in Furnace
4. Fabrication
5. Annealing
Collection:
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Depending on types suitable raw material is collected
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In addition,cullets and decolorizes are also added
Cullets:
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Waste glass or pieces of broken glass
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Increase fusibility of glass
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Prevent loss of alkali by volatisation
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Reduce the cost
Decolorizes:
Raw Materials like
USES:
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The fiber glass reinforced with plastics can be used in the construction of
furniture, lamp shades, bathroom fittings, navy boats, aeroplanes , cars ,
trucks etc.
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In the construction of modern homes, the walls and ceilings of hollow glass
blocks can be made. Cuts off the glare
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Admits sunlight and controls sound and heat in a better way.
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Color changing glass- a window with such glass will be transparent during day
time and it will be source of light during night.
SPECIAL TYPE OF GLASSES:
The following are the special types of glasses with modified properties:
1. Sheet glass
2. Plate glass
3. Safety glass
4. Tinte coated glass
5.
Glass Blocks
Soda lime (soda glass or soft glass glass-cheap, available in clean and clear
state.
o
REFLECTIVE FLOAT GLASS:
1) CVD coated tinted glass
2) Can be for tempered, hot curved and
laminated
3) Width: 5mm 4) Size: 1,200 x 900 – 3,300 x
6,000mm 5)
4) Applications: walls, doors, windows, indoor
decorations
LOW E-GLASS:
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Low emissivity (low e) is a quality of a surface that radiates, or emits, low
levels of radiant energy,
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Emissivity is the value given to materials based on the ratio of heat emitted
compared to a blackbody, on a scale of 0 to 1
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To make low-e glass, certain properties such as the iron content may be
controlled
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Specially designed coatings, often based on metallic oxides, are applied to
one or more surfaces of insulated glass.
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These coatings reflect radiant infrared energy, thus tending to keep radiant
heat on the same side of the glass from which it originated,
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It allows visible light to pass.
FOAM GLSS:
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Prepared in the form of rectangular glass blocks
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Finely ground glass and carbon are mixed and melted to get foam glass
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During melting it expands and assumes form of a black foam
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Contains more than 350 million inert air cells per cu.m
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Foam glass can float in water
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Can be cut like wood
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Fire-proof, rigid and an excellent heat insulator.
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Can be a substitute for cork in refrigeration industry
GLASS BLOCK
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Partially evacuated and completely sealed hollow units which are
formed by fusing together two – halves of pressed glass.
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Sq sizes – 150mm, 200mm and 300 mm
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Thickness -100mm
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Faces of the blocks are
suitably treated to obscure
the glass and to diffuse
light. These blocks possess
high insulating value and they are
set in cement motor.
Advantages
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They are easy to clean
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Excellent light transmission
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Very good insulation against cold
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Heat and noise.
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Glass brick, also known as glass block, is an architectural element made from
glass. Glass bricks provide visual obscuration while admitting light.
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Used in the early 1900s to provide natural light in industrial factories.
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Installing glass bricks is in a cement based mortar.
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These mortar joints are reinforced with stainless steel rods of 5-6 mm
diameter horizontally and vertically to improve both the strength of the
glass brick panel and to help achieve fire resistance where required.
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Most glass bricks require a 10-15 mm mortar joint to accommodate any
minor irregularities in the alignment of the.
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Specially shaped plastic spacers within the mortar joints to enable the
panel to be constructed more quickly and accurately.
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Provision must be made when installing glass blocks to allow for differential
thermal expansion of the glass.
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This is normally achieved by installing a ‘sliding’ joint at the base of the panel
and the inclusion of a compressible packing strip at the panel’s abutments
with the jambs and head.
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Panel’s perimeter are packed with a compressible material usually a
polythene foam
Heat Excluding Glass:
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This glass allows light to pass thro it but it eliminates heat. It is used in
windows of coaches of higher class in railways, in window panels of important
buildings.
Obscured Glass
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Used at places where light is to be transmitted and vision is to be obscured.
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Uses – public toilets , office doors, partitions etc
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Figured glass, corrugated glass
Perforated Glass
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Perforations are made in sheet glass with the help of rollers panels in
ventilators.
Safety Glass:
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They area shatter proof glass
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Glass is formed by placing celluloid between two sheets of the plate glass and
then applying glue to make a single unit
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They do not fall apart when broken
Shielding Glass
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Special variety of glass and it contains heavy elements like lead oxide.
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Windows – high radiation is observed
Ultra Violet Glass
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This glass transmits effectively ultraviolet rays even though it is not in the
direction of sun.
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Uses – windows of schools and hospitals
STRUCTURAL GLASS
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Glass – crete squares or lenses which are set in cement concrete and
reinforced with steel frames- glass bricks-light structural members also,
pavement lights, partitions. Lantern lights etc.
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Stair and upper landing with glass beam support
WIRED GLASS:
Wired glass is float glass which has been formed with a layer
of fine wire mesh in the centre of its cross-section.
This layer of mesh is visible when the pane of glass is looked
through. Wired glass is very strong and is used for security
purposes and also in locations where safety is a concern.
Steel wire mesh is placed in glass during rolling operation
Wired glass – roof, skylights, fire resisting
doors and windows
LAMINATED GLASS
It is actually two layers of glass sandwiching a thin plastic sheet.
One or both of these layers of glass may be tempered. The middle plastic sheet
serves to hold the overall glass sheet assembly together when broken.
Laminated glass is used in automotive windshields and in buildings where safety is
a concern
INSULATING GLASS (IG)
Glass units are hermetically sealed combinations of two or more tiles of glass
separated by a dry airspace. IG units improve thermal performance, significantly
reducing heating and air conditioning costs. IG units also reduce interior
condensation in cold climates.
A wide range of applications include:
Fixed and Operable windows
Storefronts and Curtain Walls
Sloped/Overhead Glazing
Non vision (Spandrel) Locations
HEAT TREATED GLASS
Heat-treated glass is glass that has been processed through a tempering oven to
increase its strength to resist impact, mechanical loads and thermal stress
breakage.
There are two distinct heat-treated glass products,
1. heat-strengthened
2. Fully tempered.
APPLICATIONS:
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Doors: Patio, Entrance, Storm and Sidelites
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Tub and Shower Enclosures
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Windows: Commercial/ Residential, Fixed and Operable
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Displays, Partitions
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Storefronts and Handrails
LAMINATED GLASS
It is a multifunctional glazing material that can be used in a variety of applications.
It is manufactured by permanently bonding two or more tiles of glass with layers of
polyvinyl butyric (PVB) interlayer, under heat and pressure, to create a single
construction
APPLICATION:
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