Glass For Architecture

In the construction of modern buildings, glass has become an essential component. With modern technology, the permutation of glass types has been both varied and exciting. There have been applications in both small and large amounts – from kitchen wall splash backs, cabinetry and staircase balustrades and threads, to laminated double-glazing for office buildings and skyscrapers.

So which type of glass is suitable for what kind of application?

Here we take a look at the different types of glass, their classifications and specifications, as well as the way glass is used.

Glass Types

1. Float Glass/Annealed Glass

– Distortion free
– Precision-flat
– Clearly transparent

2. Tinted Float Glass

– Solar control and absorption of solar radiation energy
– Cuts down heat transmittance
– Reduce cooling load
– Glare reduction
– Tinted green, blue or grey

3. Low-Iron Glass

– High clarity and transparency
– Low iron oxide content
– No green tint that is inherent in normal float glass

Thermal Treatment
Glass is treated with heat to enhance its properties. The main benefit of the process is to strengthen the glass. Basically, float glass is heated to near softening point and then quenched by blasting cool air rapidly. The surface of the glass is compressed as it is cooled faster than its core, thus compressing it.

1. Tempered glass

– Impact resistance – can withstand the static load resistance 3 to 5 times that of float glass and impact resistance of 5 to 10 times of float glass of same thickness
– Temperature resistance – it can withstand temperatures of 150 degree Celsius compared to float glass which can only withstand temperatures of 40-50 degree Celsius
– Safety – breaks into small pieces instead of float glass which breaks into large knife-like shards that can cause injury

It is applied in shower screens, balustrades, signage, doors and windows and interior and other decorative uses due to its safety properties. It is also known as safety glass.

2. Heat Strengthened glass

– Impact resistance – is 2 times stronger than float glass
– Temperature resistance – it can withstand temperatures up to 295 degree Celsius.
– Safety – breaks into larger pieces but holds within its frame as intermediate glass pieces support each other
– Impurities – there is virtually no impurities of nickel sulphide so there is little risk of spontaneous breakage

It is often used for architectural facade glazing. This is because it combines well with lamination – allowing the interlayer to be laminated better as this surface is smoother and flatter. This is due to its lower levels of surface compression. The smooth surface also allows better clarity and transparency.

With is flatter surface it also allows for laminated layer to adhere well and reduce optical distortion. Therefore it is often used for double glazing and laminated glass.

However heat strengthened glass is not suitable for areas where there is close human contact as it breaks in larger pieces which can be dangerous. Where Fire access panels or breakable panels are required, tempered glass is used.

3. Laminated Glass

Laminated glass basically involves bonding 2 pieces of glass with an interlayer also known as a PVB (Polyvinylbutyral).

– Safety – When the glass is broken, the interlayer holds the glass shards in place, thereby reducing chance of injury. It is therefore a good safety glass.
– Impact resistance – The interlayer is able to absorb force. The interlayer can also resist penetration.
– Sound reduction – The glass has powerful acoustic ability as the interlayer acts as a sound insulator.
– Glare control – By tinting the interlayer, it is able to reduce the heat/glare load by absorbing direct radiation from the sun. This also helps to reduce the cooling load for the building
– UV reduction – These harmful ultra-violet rays of the sun is cut out (99%) thereby protecting internal elements such as furniture. However, it allows the light necessary for the photosynthesis of plants.

Laminated glass is suitable for internal but more popular with external glazing applications. The PVB layer can also be made of various colored tints and textures. This is used in inventive ways for interior works.

4. Low-E glass

– Good thermal property- frequently used for office buildings with its continuous curtain wall glazing. The insulating property cuts out significant radiation and reduces the cooling load.
– High transparency – The glass is highly transparent and clear
– Low-reflectivity – it allows most sunlight to enter in the visible range without altering its natural color. Provides excellent natural illumination and save energy by reducing need for artificial lighting.