Sustainable Cities™

The Sky City Building

The Sky City Building in Changsha, China looks great on paper, and if built could revolutionize skyscraper and city design, resetting the rules for sustainable living. However city planners, engineers and architects have voiced their reservations.

Sky City broad pic

The Very, Very Tall Building!

The Sky City Building, is supposed to be 838m tall; the tallest in the world, have housing for over 30,000 citizens, endless facilities, a sustainable design and a construction schedule of only 3 months! But the building which was originally proposed to be completed by June 2013 has  experienced multiple delays and is surrounded in controversy.

China is undergoing vast urbanization (See DAC Sustainable Cities article KINA: URBANISERING I DET EKSTREME) and with it comes a huge demand for skyscrapers. In the next 5 years the country will have 60 skyscrapers over 300m; this is currently as many as the rest of the world combined. The Sky City building will be at the peak of this number. It will outreach the Burj Kahlifa in Dubai by 10m to become the world's tallest building and a statement of intent from the Chinese government.

Sky City 3Photo: Broad Sustianable Buildings

The building will boast 202 floors, with 90% of materials pre-fabricated off site and then assembled in 90 days, a feat of construction never seen before. The mass of floor space, over 1 million m², will largely be for residential purposes; a planned 5000 residential properties will be able to accommodate over 30,000 citizens. Sky City will also offer a 1000 room hotel, 5 schools, vast office and retail space, basketball and tennis courts as well as 4 helipads. The citizens and visitors will be transported by 104 high speed elevators, taking a number of minutes to get from top to bottom.

The designers, Broad Sustainable Buildings (BSB)  propose sustainability as one of the highest priorities for the Sky City building. The company has planned a number of impressive design features including, 20cm thermal insulation; saving 70% heat loss compared to conventional buildings, 4 paned glass windows, external solar shading, fresh air heat recovery and a gas fired cooling, heating and power system with a HVAC energy consumption of 90kWh/m². There will also be a 100% fresh air ventilation system with a 3 stage filter system meaning the air will be 20 times cleaner inside than outside! The high density, mixed use functionality of the building and an absence of conventional transport modes helps increase the sustainability factor of Sky City in its operational lifetime. The building also claims to preserve 200 hectares of surrounding land in addition to the 56 sky parks and 8000m² of open sky gardens. A vast 86,400m² vertical organic farm will also be constructed. And for those not fond of elevators there will be a 10km 'street' connecting the 1stand 170thfloor!

Sky City looking upPhoto: Broad Sustainable Buildings 

The numbers are impressive but why so much criticism?

Criticism of the building has been widespread throughout China and the wider planning and architectural communities. This is not new for groundbreaking buildings but some think the ability of BSB; a company which has not yet constructed a building over 30 stories, has bitten off more than it can chew! Skepticism has been fuelled by concerns over issues such as structural integrity, fire safety, evacuation plans and funding. The general motivations of BSB's Group Chairman Zhang Yue, an air conditioning tycoon, have also come under the spotlight. Such concerns have coincided with local government building permit delays, suggesting uncertainty in local planning offices. Since the groundbreaking ceremony which took place in July 2013 there has been little progress in preparing the foundations for Sky City.

The story is just beginning

Regardless of the current situation, the Sky City building with its ambitious outlook for city life has opened the debate of how megacities, cities and individual skyscrapers of the future are designed and constructed. Is this a model for sustainable urban life?

Look out for further cases on China's urbanization and city development here at DAC Sustainable Cities.


Friday, September 13, 2013 / By Christopher William Reeves

Last updated Tuesday, April 22, 2014