The many faces of polycarbonate

With a plentiful range of benefits, not least its versatility, James Patrick from Kingspan Insulated Panels explains why designers can view polycarbonate as an architectural material in its own right:

Introducing as much natural light into a building as possible is a key maxim of good design. It helps to reduce energy consumption, creates healthier environments, and has been proven to have beneficial effects on occupants such as increasing productivity, speeding healing and reducing the risk of depression. Too much glass on the other hand, can lead to uncomfortable levels of glare and over- heating. Enter polycarbonate – a material that can allow excellent levels of daylight through both roof and walls, without the same risk of too much glare and heat.

Characteristics

At a fraction the weight of glass or acrylic, polycarbonate is nevertheless extremely strong – so much so that it is a material that is used to make bulletproof police shields. It is easy to mould and extrude, so it can be manufactured to integrate seamlessly with other building components such as insulated panel systems. Best of all, it can admit the same amount of natural light as glass, but offers high levels of thermal resistance, helping to reduce solar heat gain, as well as the capacity to reduce glare and increase uniformity of illumination through light diffusion.

Unlike some alternative materials that are commonly used for the same kind of applications, polycarbonate is highly resist- ant to UV degradation, so will not yellow or lose translucency over time, barely reducing its levels of light transmission for decades. Together with its strength, this adds durability to its list of virtues. Tints can also be added to the normally clear material to add a whole new design dimension through the use of colour and enhance light diffusion.

There is a perception that polycarbonate is sensitive to thermal expansion when through fixed, increasing the possibility of stress cracking in roof and wall light applications. However, multiwall polycarbonate products are available which greatly reduce the potential for thermal expansion, resolving this issue.

Last, but not least, polycarbonate is one of just four materials that have been identified by the World Economic Forum as having the capacity to be 100 per cent remanufactured with no loss in material quality, no matter how many times it is recycled, making it a truly circular economy product.

Polycarbonate in action

One of the most instantly recognisable uses of polycarbonate is in rooflight products, where its excellent light transmission coupled with light weight and high levels of non-fragility make it an ideal material for roofing applications. Most often associated with warehousing and industrial type buildings, rooflights allow natural light to be introduced deep into the heart of large buildings where normal side glazing simply cannot reach. With the growing interest in the benefits of daylight on health and wellbeing, there is also an increasing use of rooflights to illuminate areas of buildings such as schools and hospitals that would normally rely on artificial lighting.

The proportion of rooflights must always be balanced to achieve a thermally efficient building envelope, and polycarbonate products can also help here, achieving

U-values as low as 0.8 W/m2.K. If you are looking to achieve a high BREEAM rating, there are up to six credits available for visual comfort under Hea 01 of the latest scheme – BREEAM UK New Construction 2018. Areas for consideration include glare control, daylighting and internal lighting levels.

Polycarbonate products are not restricted to rooflights. Wall polycarbonate solutions can be used to great effect, not only to introduce clear light into buildings but also to bring visual life and colour to both the exterior and interior. The impact of light through tinted panels can be energising or restful, playful or cathedral like, creating new dimensions to the spaces where people live, learn or work.

Let the light in

With so many beneficial characteristics, and so much versatility, it is time to recognise that polycarbonate does not just provide useful products for industrial buildings; it is an architectural material in its own right. It can be shaped and coloured, recycled and made anew, it can be subtle or striking. Most importantly of all, it can bring natural light flooding into all kind of buildings, without glare and without overheating.

James Patrick is technical services manager at Kingspan Insulated Panels