Promise of polycarbonate
Polycarbonate offers numerous advantages over conventional materials for roofing and glazing, as Murali Mohan, general manager, Bayer MaterialScience Pvt Ltd explains
Wood was the first material used for roofing in homes and structures. As civilisation progressed, wood was replaced with brick and mortar.
These were then supplanted with cement and concrete as roofing had a load bearing act to do.
Even wooden windows have been replaced with aluminium profiles, powder coated metal frames and glass. All these materials have their own strengths and characteristics and have performed well under different conditions for a fairly long period of time.
Since the mid 1980s engineering thermoplastic materials like polycarbonate were tried for roofing applications in Europe, USA and other developed parts of the world. Polycarbonate sheets due to their transparency, lightweight and virtually unbreakable nature can be used to construct light and airy architectural designs.
This wonder material is 250 times tougher than conventional glass. Polycarbonate sheets of sufficient thickness can take on substantial amount of load and have substituted glass in traditional applications like windows in rail coaches which has seen too much of vandalism. When it comes to clarity in terms of light transmission, a polycarbonate sheet is as good as glass.
As the world is gripped with the subject of energy and cost savings, companies are expeimenting with new generation materials. There is a growing trend towards cost-efficient construction materials that meet the highest standards in terms of environment requirements.
For instance, Bayer MaterialScience has developed a UV stabilised Makrolon polycarbonate corrugated sheets. These are popularly used in green houses and mainly by companies involved in bio-science. They are also being used as roofing application over walk-ways, bus shelters and foot-bridges.
The polycarbonate multi-wall sheet with UV protection is a versatile material seen in creative construction projects all around the world. Extremely light weight and flexible, the range includes thick and rigid sheets and offer high heat insulation properties. It comes in different geometries and coloured sheets, is transparent or translucent.
It can be used in many diverse glazing applications in industrial roofing, malls, sports halls, stadiums and continuous roof lights.
There are flame retardant grades in these sheets which have B1 classification according to DIN 4102 part 7. There are also hail resistant sheets which have a reinforced top layer which protect the roof against hail.
Artificial and natural weathering tests have shown that the sheets continue to deliver an excellent performance even after 10 years.
Greener than thou
Technology has vastly improved in the manufacture of new generation polycarbonate sheets. One such product line is on intelligent and energy-saving solution. The sheets reduce the temperature inside the building by reflecting the infra red portion of sunlight.
A six wall sheet in this category illustrates how the material contributes to the economic efficiency of construction projects. The sheets have a heat transfer co-efficient (Ug) of 1.82W/m²K and an optimal ratio between Ug factor and sheet thickness.
This material reduces the energy consumption in buildings by up to 25%. Tests in unventilated conservatories have shown remarkable reduction in temperature (as compared to other material).
Heat build-up during summer becomes more of an issue in modern constructions, particularly in Indian conditions. Large glazed areas have become a key part of modern architecture, while environmentally friendly solutions become necessary to avoid excessive use of air-conditioning.
It is clear that technologically advanced polycarbonate sheets offer various advantages over the conventional materials. They are very useful for roofing applications in various structures like railway stations, stadiums (both indoor and outdoor), green-houses, porches, facades, malls, hurricane shelters, sound dampening walls along highways, and rail-tracks.