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Types of glass

About Glass - An Overview

Glass is one of the most important materials in usage and finds many practical applications in our daily lives and throughout the world. Generally, glass is characterised as a transparent solid material that can be used to make a variety of products in fields like architecture and design. If we stick to the definition of glass, then scientifically, it is defined as a non-crystalline amorphous solid that has the property of transparency, and is used for practical, technological and decorative purposes.

What is glass made up of?

Of all types of glass, silicate glass is the most common and widely used. This type of glass is based on the chemical compound silica, also known as silicon dioxide or quartz. Silica is most abundantly found in sand in the form of a mineral called quartz. While silica is the main constituent of glass, other chemical compounds such as sodium oxide, sodium carbonate, and lime or calcium oxide are added to it in order to yield glass of desirable properties such as the right melting point and viscosity.

Out of all manufactured silicate glass, soda lime glass accounts for more than 90% production. It contains 75% silica, sodium dioxide, lime, magnesia or magnesium oxide, and alumina or aluminium oxide.

Soda lime glass is the glass used in architectural and automotive applications.

What are some of the most important properties of glass ?

Here are a few general properties of glass:

  • It is usually transparent
  • It has a smooth surface
  • It has a clear appearance
  • It can reflect, refract and transmit light without scattering it
  • Silicate glass can be poured, formed, extruded and molded into many shapes including flat sheets and complex designs
  • It is brittle
  • It is erosion-resistant, especially against the action of water
  • Usually resistant to chemicals, and is also corrosion-resistant
When did glass come into use?

The earliest known usage of glass can be dated back to the Stone Age when naturally-occurring volcanic glass was used to create weapons and tools. Strong archaeological evidence suggests that glass manufacturing first began in Mesopotamia and Egypt around 3rd millennium BCE. In South Asian countries like India, glass manufacturing first began around 1730 BCE. Evidence for this has been discovered in the ruins of the Indus Valley Civilization. From there on, glass came to be extensively used, especially in the Middle Ages when glass windows, jewellery, vessels, etc. were manufactured. Specialized glass variants such as laminated glass are a 20th century innovation.

How is glass manufactured ?

In today’s world, modern glass variants are produced from float glass. Float glass is a sheet of molten glass on a bed of molten metal such as lead or tin. This sheet of glass is of a uniform thickness and smoothness, thus allowing manufacture of extremely flat glass surfaces.

Float glass, usually soda lime silicate glass, is produced by the PPG process discovered by Sir Alistair Pilkington. In this method, first, the raw ingredients of glass are mixed in a batch in pre-defined ratios. These raw materials include:

  • SiO2 or silica sand
  • Na2O or sodium oxide from soda ash
  • CaO or calcium oxide from limestone/dolomite
  • MgO or dolomite
  • Al2O3 or feldspar
  • Broken glass or cullet

These materials result in formation of clear glass. In order to impart colour to the glass, other raw materials such as CoO or Fe2O3 are added to the mix. This mixed batch is transferred to a furnace at 1500 degree Celsius. As a result, the batch is melted, and then passed over to the mirror-like surface of molten tin float bath at 1100 degree Celsius. From here, glass leaves as a ribbon at a temperature of 600 degree Celsius. Thereafter, soft or hard coatings to modify the optical properties of the glass are applied to its surface in quick succession. The internal stresses of glass are removed and finally, the glass is cooled gradually before being cut to order.

Types of Glass

While there are many different ways in which glass can be categorized, here we will focus upon the various industries or verticals where glass applications are prevalent. Since glass is a unique material with unique optical properties, it is hugely popular in the automotive and architectural industry. While in the former, glass manifests itself as windshield and other components of automobiles and vehicles, in the latter, glass is used in doors, windows and other interior and exterior design and construction of buildings.

Other category of glass based on industry includes solar glass.

AUTOMOTIVE GLASS

Automotive glass includes laminated and tempered glass applications in the form of vehicle components such as windshields, side windows, mirrors, headlight and tail-light glass, etc. Glass is an important component of vehicles since it provides structural integrity and also shields the occupants from external elements on the road.

Tempered Glass for side windows

Tempered glass is a type of glass that breaks into small blunt pieces instead of sharp dangerous shards upon collision. Thus, it is used in the side windows and rear windshield of automobiles and does not harm the passengers in the event of an accident.

Laminated Windshields

Laminated glass is a type of glass which consists of two sheets of glass with a plastic interlayer separating them. Thus, laminated glass is quite impact resistant, and in the event of breakage its glass pieces remain stuck to the plastic interlayer, thus protecting the passengers from injury. For this reason, automotive laminated glass is used in windshields.

Value-Added Glass Products

Automotive glass also includes other applications and accessories in vehicles such as defogger glass, glass antenna, encapsulated glass, PET windshield, water-repellent glass, rain sensor windscreen, etc.

ARCHITECTURAL GLASS

Architectural glass includes special types of glass used for building design and construction applications such as windows and doors. This glass is tailor-made to provide specific functionalities to the space they are utilized in such as security, privacy, noise insulation, energy efficiency, aesthetics, pollution control, etc.

Annealed Glass

Annealed glass or float glass is the most basic form of manufactured glass that lacks the toughness or impact resistance of processed glass.

  • Clear Glass

    Clear glass is a kind of float glass which offers extreme transparency and clarity. AIS Clear Float Glass is the highest quality clear glass with high precision flatness.

  • Tinted Glass

    Tinted glass is annealed glass that has a coating or a film that imparts it colour and reduces its light transmission. AIS Tinted Glass is a body tinted glass which absorbs energy from solar radiation.

  • Frosted Glass

    Frosted glass is a translucent glass made by the process of sandblasting or acid etching. Its pitted, rough surface gives it a foggy appearance, thus making it the perfect solution for privacy. AIS Krystal, India’s only branded Frosted Glass, obscures the view while allowing light to pass through it.

Coated

When certain coatings are applied to processed glass, they change its optical and heat transmission properties. Other enhancements due to glass coatings include changes in solar insulation, anti-reflection, water resistance, etc.

Soft Coat
  • Low-E Solar Control Glass

    This is a high performance glass with a low-E (low emissivity) coating which allows the glass to be energy efficient by cutting down on heat transmission. Yet, low-E soft coated glass such AIS Ecosense provide optimum light transmission, thus being preferred in green glass architecture.

  • Heat Reflective Glass

    Heat reflective glass such as AIS SunShield is another high performance product which has advanced solar control technology to reduce heat and glare from entering the building.

Hard Coat
  • Exterior solar control glass

    This type of hard coated glass, such as the AIS Opal, is used in the exterior of buildings for providing optimum solar control.

  • Mirror

    Plane mirrors, as we all know, are used to reflect back the image of the object placed in front of the mirror. AIS Mirror is distortion-free and an environment friendly product that does not use copper and lead in its glass manufacturing process.

  • Lacquered Glass

    Lacquered glass is a type of decorative glass which has a colour coating on one of its surfaces. AIS Décor has a coloured opaque appearance achieved with oven-cured high quality paint.

Processed Glass

Processed glass is a type of glass made by subjecting annealed or float glass to thermal or chemical treatment in order to change its properties. There are various processing techniques such as lamination, toughening, sandblasting, acid etching, lacquering, enamelling, glazing, etc. The two main types of processed glass are laminated glass and toughened/tempered glass.

  • Laminated Glass

    Laminated glass is a type of security glass manufactured by sandwiching a layer of plastic such as PVB in between two sheets of glass. This insulator layer makes the glass impact resistant and sound resistant. Laminated glass, upon breakage, remains intact as the broken pieces stick to the interlayer.

    AIS Securityglas, AIS Securityplus and AIS Valuglas are high end safety glass, whereas AIS Acousticglas provides 90% sound reduction.

  • Tempered Glass

    Tempered glass or toughened glass is formed by heating annealed glass in order to develop opposite stresses on its surfaces. This makes toughened glass much stronger than regular glass. AIS Stronglas is a very high grade tempered glass that is several orders of magnitude stronger than ordinary glass.

  • Fire-resistant Glass

    Fire-resistant glass, such as AIS Pyrobel, is a multi-laminated glass with an intumescent layer which can withstand extreme levels of heat, smokes and flames.

  • Swytchglas

    Smart glass such as AIS Swytchglas, is a type of glass that switches its optical transmission properties due to passage of current. Thus, this glass can change from transparent to translucent and vice versa within seconds.

  • Retrofitting glass

    This type of glass, such as AIS Renew, has a low-E interlayer and is applied above old windows in order to make them more energy efficient.

uPVC, Aluminium & Wooden Doors & Windows

When it comes to glass for doors and windows, the most common profiling option available include uPVC, wood, and aluminium. These architectural solutions allow the doors and windows to have adequate structural integrity, weather resistance, heat and noise insulation, etc. AIS Windows specializes in these architectural solutions for homes, offices and commercial spaces.

SOLAR GLASS

Solar glass is a type of glass that has applications in the solar energy manufacturing industry. Solar glass is used in various components such as solar mirrors, solar panels, solar cells, etc. in order to harness the energy of the sun.

AIS Solar Glass deals in all these products in the Indian solar glass segment.

 

Applications of Glass in Buildings

Thus far, we have read what glass is, how it is manufactured and how is it used in various industries. Now, we let’s cast a closer look at its application in different types of buildings.

Residential & Commercial Buildings

Broadly speaking, different kinds of architectural glass can be used in different buildings based on the functionality required. These buildings and requirements can be of the following nature:

  • Residential – Glass applications in home are based on creating a comfortable and safe living space. Thus, glass doors and windows are often used to cut down on heat and glare, filter out external noise, increase natural lighting, provide security, or improve the décor.
  • Professional – Glass applications in offices are based on creating a productive environment. Thus, facades, cabins, partitions, doors, windows, etc. are tailor-made to increase privacy, cut down noise, and increase the energy efficiency.
  • Hospitality – Glass applications in hotels are based on creating a relaxing and appealing aesthetic for guests.
  • Healthcare – Glass applications in hospitals are based on creating a comfortable, safe and peaceful ambience for patients while also upholding their privacy and insulating noise.
  • Retail – Glass applications in retail stores are based on creating an attractive and comfortable environment for customers both inside and outside the store.
Interior & Exterior of Buildings

Glass applications also differ for interior and exterior of a building.

  • Interior – Doors, windows, partitions, shelves, cabinets, table-tops, panels, cubicles, blinds, staircases, etc.
  • Exterior – Spider glazing, balconies, swimming pool glazing, facades, external doors and windows, canopies, skylights, walkways, etc.