Glass in buildings: Characteristics and Functions

The glass used in today's window and façades does more things than many people perhaps realise. From prime concerns like safety, security, and environmental protection to convenient functions like self-cleaning or practical qualities like scratch resistance or design aspects, the choices are many and varied.

Themal Insulation
Solar Control
Safety & Security
Fire Resistance
Noise Control
Decorative
Self-cleaning

Thermal Insulation

Thermal insulating glass for windows and façades, also known as "low-E" (for low-emissivity) glass, usually forms the inner pane of an insulating glass unit (IGU). A transparent metallic coating reflects heat back into the room rather than allowing it to escape through the windows. At the same time, low-E glass allows solar heat to pass into a building and warm the interior (this is known as "passive solar heat gain").

Recent regulations call for the use of energy-efficient products to cut CO₂ emissions and protect the environment. Thermally insulating double-glazing is a way to meet national government targets and cut domestic fuel bills.

Thermally insulating glass can be one of several desirable maintenance, solar control, noise reduction, decorative glass and enhanced safety and security.

Solar Control

Solar control glass is glass designed to reduce or prevent solar heating of buildings. There are two approaches that can be used: the glass is either tinted (coloured) throughout the material (called a "body tint"), or else it has a microscopically thin and transparent coating on one side.

In the body tint approach, the colour causes the glass to absorb solar energy, which is then re-radiated back out and away from the building. Coated glasses immediately reflect the heat away.

These technologies reduce the solar heating that tends to take place in large buildings, and thus reduces the need for air-conditioning. It is therefore an energy-saving technology.

In dwelling houses it helps prevent uncomfortable overheating in conservatories and other rooms with large areas of glazing, and it can also reduce irritating glare from direct sunlight.

Solar control glass can be combined with many other features for multifunctional glazing, such as thermal insulation, self-cleaning, noise reduction, decorative glass and enhanced safety and security.

Safety and Security

To improve its resistance to impact and breakage, glass can be either toughened or laminated, depending on where and how it is being used.

Toughened glass offers a distinct safety advantage, not only being less likely to break but also, when it does break, producing very small fragments that are relatively harmless.

Laminated glass can be made so strong that it is practically impossible to break through, making it possible to use glass wherever desired, even where high security requirements apply including bullet-resistant applications. In the case of breakage, fragments adhere to the flexible "interlayer" between glass layers, reducing the chance of injuries.

These features can be combined with other glass functions for additional comfort: thermal insulation, solar control, acoustic insulation, low-maintenance and decorative glass.

Fire Resistance

A range of fire-resistant glass types is available that offers increasing levels of protection, which is measured in defined time periods (30, 60, 90, 120, 180 minutes). Fire-resistant glass must meet strict levels of integrity and insulation, or integrity-only which are set down by European CE standards. Fire-resistant glass must always be specified as part of a tested and approved glazing system and installed by specialists to be sure of reaching expected fire performance, if required.

Noise Control

Acoustically insulating glazing can be a major contributor to comfort levels in buildings and houses. Its benefits are greatest for people living or working near busy high streets, urban traffic, motorways, railway lines and airports, or on a flight path.

The acoustic glass in a double-glazed unit uses a special interlayer that acts as a dampening core so that sound energy is effectively blocked from passing from the outside to the inside pane of glass.

Acoustic glass can be combined with many other products for multifunctional glazing, such as thermal insulation, solar control, and self-cleaning glass.

Decorative: Interior Design

Glass can transform living spaces and work environments. A wide range of effects, patterns and colours allows interior designers endless possibilities in look and atmosphere. Glass can be combined with stone, wood or metal for a strong visual and tactile effect. In offices and other professional settings, glass offers a fresh, light yet serious aesthetic and has the advantage of being a material that wears exceptionally well and is impervious to moisture and most cleaning products.

Self-Cleaning Glass

Self-cleaning is glass that has been coated with a special dual-function layer that harnesses the elements windows and facades are exposed to - namely, sun, and rain - to break down and wash away dirt. This first function is photo-catalytic; in other words, it is activated by light to break down the dirt that collects on it. The second function is to spread rain-water evenly over the glass. Most glass is hydrophobic (water-repellent), causing water to bead into droplets before it runs off, thus touching only a fraction of the surface. The hydrophilic self-cleaning coating prevents this beading into droplets, causing water to run across the entire surface, washing away the components that the dirt has been broken down into.