Glass for Buildings - Uses and Properties

    Glass is used extensively in construction in several parts of buildings as fixed or openable glazing for architectural features and also for natural lighting.

There are various types of glass available in the market and care should be taken while selecting the correct type of glass for different types of construction.

Uses of glass

     The glass industry makes a variety of glass products for different purposes. Among all Soda lime glass is the cheapest and used for making bottles, windowpanes, etc. Pyrex glass or borosilicate glass is used for heating vessels, and Bottle glass is used for medicine bottles.

Selection of glass depends on the required size and also cost of glass. The types in glass and their uses are detailed as follows:

Sheet glass

     Sheet glass is used in small panels of doors and windows. This glass should be clear, free from blisters, scratches, waves and bubbles.

Sheet glass is available in thickness of 2mm, 2.5 mm, 4mm, 5 mm, 5.5 mm and 6.5 mm.

Usually, glass is mentioned in weight per unit square foot or square metre, i.e., 21 oz means the glass which weighs 21 oz per square foot in the f.p.s system (it will be 6.3 kg per sq. metre).

Example of Sheet glass

Many types of sheet glass are present, and they are as follows:

  1.  AA Quality or Special Quality (SSQ) - use as mirrors
  2.  A Quality or Selected Quality (SQ) - use as safety glass
  3.  B Quality or Ordinary Quality (OQ) - use for glazing in buildings
  4.  C Quality or Greenhouse Quality (GQ) - use for making frosted glass, etc.

Of all these types, OQ glass is mostly used in buildings. The specification for structures is to use 21 oz sheet glass for panels up to 24 inches, 28 oz for panels of thickness 24 to 30 inches and 32 oz for panels of thickness 30 to 36 inches.

Plate glass

     This type of glass is manufactured in a thickness of 3 to 32 mm and used in large size panels such as shop windows, manufacture of mirrors, etc. It is available in three types, roughcast, rolled or patterned and polished.

Example of Plate glass

Plate glass is stronger and more transparent with much less waviness than sheet glass.

Float glass

     At present, float glasses are the commonly used variety of glass in modern buildings. The floating process is used to make float glass, which is the most advanced method of making glass for various uses.

The float glass is of uniform thickness with excellent optical clarity and aesthetic appearance. Nowadays, the modern large sized shop windows and facade of tall buildings are made of this type of glass.

Wired glass

     In this glass, the wire set is embedded in plate glass during rolling. This glass is more resistant to fire and used in skylights.

Example of Wired Glass

Glass blocks

    These are glass units, transparent or translucent produced by a pressuring process. They consist of high thermal insulation and noise reduction and used on walls and roofs.

Example of Glass Blocks

Tinted glass

    Tinted glass is nothing but a glass with colour. It is available in three shades bronze, dark grey and auto green of thickness ranging from 2 to 12 mm. It also absorbs 30 to 40 per cent of solar radiation compared to only 15 per cent absorbed by clear float glass.

Example of Tinted glass

Bulletproof glass

     This type of glass is of 200 mm thickness, prepared by special techniques. Plastics like polycarbide are more often used for this purpose.

Translucent glass

     This glass is known as Obscured glass or frosted glass. In this glass, a pattern or texture is imprinted on one or both sides of the glass to hide the inside view.

Example of Translucent glass

Usually, only one side is frosted (textured), and the other side is flat. The frosted side should face the inside of the room (to be made obscure), and the plane glass side should face the outside. They are used in doors and windows for bedrooms, lavatories, bathrooms, etc.

Laminated glass

     This glass is also known as Safety glass and is produced by bonding together two or more pieces of glass with plastic interlayers.

This type of glass is used in automobiles for windows and windshields as it reduces the risk of injury to the people if broken.

Glass Wool

     Glass wool is also known by the name Glass fibre, which is a very important material to be used with plastics to produce glass-reinforced plastics (GRP), mostly used for purposes like waterproofing of roofs, manufacture of water tanks, etc.

Example of Glass wool

Glass wool has many uses such as filters in air conditioners, fine aggregates for finishing plasters to reduce cracking etc.

Properties and Performance of Glass

  •  It absorbs and reflects light transmission.
  •  It can be transparent or translucent based on the requirement.
  •  It is not affected by changes in the environment.
  •  It is strong and brittle and easy to clean.
  •  It is available in many forms which add beauty to the buildings.
  •  It is an excellent electrical insulator and also more resistant to chemicals.

The main aim of glass is to receive daylight into the building, which is primarily used in windows and sometimes in doors.

Glass should be used in buildings considering the following factors:

Solar Control

     To reduce the heat inside the buildings solar control glasses are used, which are of two types, the solar reflecting and solar absorbing. The reflecting type is more efficient compared to the absorbing ones. The performance of the latter can be enhanced by double glazing using clear glass as the inside leaf.

Wind Loading

     For tall buildings, the glass should withstand the wind load, in such places special devices should be used to fix the glass sheets, to their supports.

Glass fixing should be properly designed while using as structural glazing for multi-storeyed buildings.

Sound Transmission

     Double glazing of windows is greatly recommended to reduce sound transmission through windows. Proper adjustment should be there between the glasses to fill the air space where the sound is to be isolated.

In double glazing, sound insulation from outside depends on the size of windows, the thickness of glass and the air space.