I have recently joined London Sustainability Exchange (LSx), as a Project Volunteer and have been tasked to write a monthly ‘Sustainability in Architecture’ article to be included in the LSx news bulletin.
For my first article I chose the subject of glass and briefly assessed the rapid development of glass skyscrapers in the City of London.
See my article below and view the LSx Bulletin via this link: http://charityemail.org.uk/CXK-2OWJM-B78OU91O20/cr.aspx
Sustainability and Architecture- Glass Buildings
The recent development of iconic, entirely glazed skyscrapers changing the London sky line, including The Shard, The Cheese Grater and The Walkie Talkie, prompt the LSx to question how sustainable is building with glass?
Glass is a high energy, high cost material and as the construction sector develops towards transitioning to a more efficient design and building process we question is there still space for glazed buildings? The recent discussions led by architect Ken Shuttleworth and Arup engineers about whether the glass sky scraper is a thing of the past prompt the LSx to review the rapid development of glass skyscrapers in London, and wonder what the future holds for London’s landmarks.
In the 1920s Mies Van Der Rohes Glass sky scraper concept defied laws of materials and was a vision of a technological future. The Ideology of glass depicted then was of simplicity and ultimate modernism. Ninety years on we continue to heavily use glass, especially in iconic London landmarks. Despite glass being expensive and high in manufacturing energy it is still seen as modern and is vastly used in building today. In the current environmental context, the construction sector should be developing and using new innovative materials as an alternative to glass, that have a positive impact on our environment and society; materials that lay the foundation for a sustainable future.
Manufacturing glass is a high energy process and it requires extremely high temperatures. The energy used to produce glass for the entire facade of the Shard for example was on a tremendous scale. The shards white glazing means that the transparency of the building is a prominent feature however; the internal appearance appears messy and disorganised, drastically affecting its crystal shard like appearance. Furthermore, due to the particular white glazing used, the solar gains are vastly increased and require complex internal environment control. However, The Shards glazing system is passive and is coated with a colourless solar-control coating, Ipasol made by Interpane and an integrated solar blind system claims to reduce solar gain by 95%.
Fundamentally, glass lets a lot of heat in and out. The preventive method to reduce solar gains and heat loss in glazed buildings is a tremendous feat of engineering and design. The Leadenhall building nicknamed The Cheesegrater, similar to The Shard, has a technical three tiered glazing system with integrated solar blinds. Despite being a very clever and innovative solution to overheating, from an environmental and economical viewpoint, it may have been better to design efficiency into the building rather than having to expend time, money and energy to mitigate the negative impacts on internal environment caused by glazed curtain walling. Architects are fixated on glazed facades; planners desire glazing and the public enjoy the iconic stylised designs. In order to achieve efficiency in building and develop toward a sustainable built environment glazing needs to be reduced.
Despite the obvious environmental problems with building with glass, many more glass skyscrapers are planned to be completed in the City of London over the next five years. The reality is that iconic landmarks and quirky shapes dominate architectural design, prioritising aesthetics over efficiency and sustainability and it seems the vision for the future of the City of London is wholly ‘glass skyscrapers.’
Future glass sky scrapers in the City of London:
20 Fenchurch Street- The Walkie Talkie
52-54 Lime Street- The Scalpel
The Bishopsgate Tower- The Pinnacle
Completion: construction on hold since 2012