G L A S S & G L A Z I N G

Last month, the UK Government announced its plans to encourage the nation to “build, build, build” as part of its efforts to kick-start the UK economy post-coronavirus. While there is much to be admired in this sentiment, we must not lose sight of other important issues the construction and building product manufacturing sectors need to address, particularly around sustainability.

PEREGA CLEAR STRUCTURES

Built environment professionals from the independent builder and selfemployed architect, to the largest contractor and global practice will be acutely aware that the clock is everticking down to 2050. By this time the industry needs to have achieved net-zero carbon status.

In spite of some of the encouraging steps taken in the right direction, from adopting more circular design methods, to tentatively embracing digital construction technology, increasing efficiency and reducing waste, we are still some way off achieving this scenario.

This gradual drive towards carbon neutrality has also encouraged us to reappraise the materials we use in construction and how we specify them. One of these is structural glass. The last decade has seen a number of innovations in glazing products and advancements in construction methods, meaning you can improve a building’s carbon footprint through strategically placed glazing.

Here, Joe Thornton, Engineer at Perega Clear Structures, looks at some of the solutions and new thinking which are helping to deliver a greener built environment.

New light through old windows

Retrofitting windows is a cost-effective and rapid way to significantly improve the sustainability of a building. Replacing the windows and facade elements of existing building stock with modern and new technologies, especially in older buildings, can make significant improvements to the structure’s energy efficiency, reducing consumption and CO2 emissions.

One emerging example is smart glass technology, which allows the windows to adapt to fluctuating weather conditions. This could include the ability to darken in response to the sun’s rays, or to intuitively adjust its light transmissions properties as the air temperature fluctuates.

Pilkington UK recently put together a wide-ranging report on the future of glass in commercial buildings, where they explored these innovations in detail. For one contributor, Architect Ian Ritchie, the green potential of these new systems are significant, saying that smart glass will deliver “a stable, comfortable environment for occupants without automatic recourse to expensive heating and air conditioning.” As these latter two activities account for the substantial majority of a building’s emissions, this technology could significantly help reduce the carbon footprint.

Circling around the issue

If we’re going to truly deliver a more eco-friendly built environment, we must also look beyond the performance and energy efficiency of windows and facades during the operational service life.

It’s important to rethink current processes and innovate to achieve a more circular supply chain, which will reduce the glass’ embodied carbon.

Upcoming changes to the Building Regulations will go some way to providing a clear, robust framework which the construction industry can follow in order to specify more sustainably. However, more needs to be done to raise awareness that embodied carbon in many waste materials, including glass, can be as much as the emissions produced by the building itself through lighting, heating and air conditioning. Disposing of it merely adds to the problem.

One solution is to look at the way in which window and facade materials are removed on existing buildings and how they can be repurposed, recycled or reused. Often, perfectly good, undamaged glass either goes straight to landfill or is crushed up for use as road bedding, when it could have a second, third or fourth life within a new build.

Laminated glass is one product which is crying out for some fresh thinking. We should be investing in low-impact delamination technologies which will enable this material to be recycled and subsequently reused.

A multi-layered approach

Other technological innovations having a big, positive impact on the built environment’s carbon footprint are the increasing specification of double and triple glazed units. Filled with inert gas and invisible, low emissivity coatings, their systems have, according to trade association Glass for Europe, significantly improved the insulating properties of windows and facades. As we know, better insulation means improved thermal performance with less dependence on carbonintense central heating.

Equally, when specified in large, floor-to-ceiling formats, maximum natural daylight is attained, meaning reduced need for artificial lighting solutions. As an added bonus, when coupled with passive air conditioning and heating systems, solar gains can be exploited to maintain a comfortable, consistent temperature within the building.

A quick internet search will show that I’ve only scratched the surface. Ultimately, clever specification of glass, alongside other structural elements, is proven to deliver lower carbon

buildings, bringing us closer to the 2050 target.

As material experts, we need to get better at communicating the benefits of investment into sustainable technologies, especially how we dispose of, or upcycle existing glazing in urban areas. It might present a significant short-term cost now, but it will be well worth the investment in years to come. This is something we cannot afford not to address.