TYPES OF GLASSES USED IN BUILDING.

Glass is one of the most versatile and oldest materials in the building industry. Glass is a hard substance which may be transparent or translucent and brittle. The fusion process used to manufacture glasses. In this process, sand is fused with lime, soda, and some other admixtures and then cooled rapidly. Glasses used in construction purposes and architectural purposes in engineering.



PROPERTIES OF GLASS

1. Transparency 
This property allows visual connection with the outside world. Its transparency can be permanently altered by adding admixtures to the initial batch mix. By the advent of technology clear glass panels used in buildings can be made opaque. (Electro chromatic glazing)

2. U value 
The U-value is the measure of how much heat is transferred through the window. The lower the U-value the better the insulation properties of the glass– the better it is at keeping the heat or cold out.

3. Strength 
Glass is a brittle material but with the advent of science and technology, certain laminates and admixtures can increase its modulus of rupture( ability to resist deformation under load). 

4. Greenhouse effect  
The greenhouse effect refers to circumstances where the short wavelengths of visible light from the sun pass through glass and are absorbed, but the longer infrared re-radiation from the heated objects are unable to pass through the glass. This trapping leads to more heating and a higher resultant temperature.

5. Workability 
It is capable of being worked in many ways. It can be blown, drawn or pressed. It is possible to obtain glass with diversified properties- clear, colorless, diffused and stained. Glass can also bewelded by fusion.

6. Recyclable 
Glass is 100% recyclable, cullets (Scraps of broken or waste glass gathered for re-melting) are used as raw materials in glass manufacture, as aggregates in concrete construction etc.

7. Solar heat gain coefficient 
It is the fraction of incident solar radiation that actually enters a building through the entire window assembly as heat gain.

8. Visible transmittance 
Visible transmittance is the fraction of visible light that comes through the glass. 


9. Energy efficiency and acoustic control 
Energy-efficient glazing is the term used to describe the double glazing or triple glazing use in modern windows in homes. Unlike the original single glazing or old double glazing, energy-efficient glazing incorporates coated (low-emissivity) glass to prevent heat escaping through the windows. The air barrier also enhances acoustic control.


TYPES OF GLASS

1. Float glass
2. Tinted glass
3. Toughened glass
4. Laminated glass
5. Shatterproof glass
6. Extra clean glass
7. Reflective or mirror glass 
8. Patterned or texture glass
9. Wired glass
10. Low E glass
11. Heat strengthen glass
12. Back painted or lacquered glass
13. Frost glass
14. Chromatic glass
15. Double glazed unit
16. Glass wool
17. Glass blocks

1. Float Glass 
Float glass is also called soda lime glass or clear glass. This is produced by annealing the molten glass and is clear and flat. Its modulus of rupture is 5000-6000 psi. Stronger than Rocky Balboa taking punches from 2000 psi punches man Ivan Drago. It is available in standard thickness ranging from 2mm to 20mm. and has weight range in 6-26kg/m2. It has too much transparency and can cause glare. It is used in making canopies, shop fronts, glass blocks, railing partitions, etc.


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


3. Toughened Glass 
This type of glass is tempered, may have distortions and low visibility but it breaks into small dice-like pieces at modulus of rupture of 3600 psi. Hence it is used in making fire resistant doors etc. They are available in same weight and thickness range as float glass.


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


5. Shatterproof glass 
By adding a polyvinyl butyral layer, shatter proof glass is made. This type of glass does not from sharp edged pieces even when broken. Used in skylight, window, flooring, etc


6. Extra clean glass 
This type of glass is hydrophilic i.e. The water moves over them without leaving any marks and photocatylitic i.e. they are covered with Nanoparticles that attack and break dirt making it easier to clean and maintain.


7. Reflective or mirror glass 
It is called mirror glass due to its appearance like mirror. It is essentially ordinary float glass with a metallic coating that cuts off solar heat. This special metallic coating also provides a one-way mirror effect, preventing visibility from the outside and thus preserving privacy. Reflective glass is used primarily for structural façade glazing.


8. Patterned or texture glass
It is a decorative and translucent glass which is patterned or textured on the one side of the glass for diffusing the light and obstructing the visibility from the outside. It maintains the privacy for interior of the house, exterior windows and bathroom windows.


9. Wired glass
In this glass, the wire mess is inert into to glass to protect from shattering and breaking out under stress. It is a low cost fire resistance glass. It is also used to protect against the harmful effects of smoke and flame. So it is used in fire doors.


10. Low E glass
Low E glass has excellent thermal insulating properties. It only allows the sunlight entering into the building and prevents harmful UV rays and infrared rays. It maintain the temperature of interior and provide energy efficient solution.


11. Heat strengthen glass
Heat-strengthened glass is a heat treated glass which retains the normal properties of ordinary float glass. It is similar to tempered glass except that the cooling is done slower than toughened glass but faster than annealed glass. Heat strengthening increases resistance to mechanical and thermal stress up to 130 Degree Celsius. While Heat Strengthened Glass is twice as strong as annealed glass, its fragmentation pattern is the same as annealed glass.


12. Back painted or lacquered glass
Lacquered glass is also known as back painted glass (BPG) is obtained by coating the back surface of a float glass with lacquer. They offer an opaque and shiny surface. The lacquered glass is available in many different shades of colours, which can be suited to any application. As the lacquer is applied to the back of the glass, it is protected from damage, ensuring durability. Its brilliance is far superior to that of gloss paints.



13. Frost glass
Frosted glass is a clear sheet of glass that is turned opaque through the process of sandblasting or acid etching. This creates a pitted surface on one side of the glass pane and has the effect of rendering the glass translucent by scattering the light which passes through, thus blurring images while still transmitting light.


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


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


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


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

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