Architect Julie Futcher, a member of the Chartered Institute of Building Services Engineers, on the effects skyscrapers have on energy use in cities
Other than the impact on the skyline, what are the problems caused by the piecemeal approach to planning skyscrapers in London?
The lack of full accountability on their effects – not only in terms of architectural contribution or links to infrastructure, but on outdoor space and other buildings. We have no way of evaluating the influence the form a building takes outside of its envelope – how they affect each other and their interdependent energy relationships. They are seen as isolated entities, even when sited in cities and surrounded by other buildings.
Are tall building clusters a bad idea?
It depends on the building’s use. If the Strata Tower with its wind turbines became the core of a dense cluster, its uninterrupted access to the wind would end – the wind resource would be dramatically reduced. Likewise, consider Heron Tower’s photovoltaic cells, which provide a significant contribution to its building energy management. What if it were surrounded by equally tall buildings (as it appears will happen)? Effectively, it would lose access to the solar resource.
An example of a good cluster would be the eastern cluster in the City of London, an area of tall office buildings where mutual shading lowers solar gain and lowers energy demand for air conditioning in individual towers.
Are planning departments equipped to look at the side-effects of towers?
Planning departments have limited powers, and, like most building professionals, have limited knowledge outside their area of expertise in evaluating these effects. As building and urban designers, we are ill-equipped to look at the broad spectrum of these mutually dependent effects in the urban setting. We need a cross-disciplinary approach towards urban planning and design that draws together the vast body of knowledge and experience.
Do you agree that a skyline commission should be set up?
Without a doubt. A skyline commission is needed even if we brought together the range of expertise and opinions on tall building and set some strategic guidance. It is not possible to address the challenges London faces by looking at the skyline issue in isolation. In fact, I doubt that such a commission, even if it were integrated with a London-wide model, could address all the challenges that we face, but it would start a conversation.
What lessons could we learn from other cities about high-rise schemes?
There is not one single lesson that can be learnt from other cities. Each has its own qualities and problems. The places that are often referred to as vertical cities are New York and Hong Kong but they are very different cities in different climates. In the case of Hong Kong very tall buildings - rather than relatively tall buildings - are the norm as the population of the island is concentrated in a small urban footprint. What is remarkable is the shear density of tall and narrow residential buildings.
From one perspective Hong Kong has achieved a degree of sustainability as the population is served by public transit systems and the street life is extraordinarily vibrant – in fact many dwellings have limited kitchen facilities on the basis that residents will eat out.
Of course it is a tropical environment and to cope with the hot and humid conditions many apartments will be air conditioned. For those that cannot afford air conditioning the urban environment can be stressful; tall buildings block the flow of cooler ocean air into the city and the high traffic and limited ventilation result in poor air quality. HK is now trying to address some of the environmental problems caused by countless decisions on individual buildings by identifying ventilation corridors and modifying urban form accordingly.
Another city to consider is São Paulo, Brazil, which has recently changed its planning laws to increase the number and height of its towers. Currently, whilst São Paulo has many tall buildings, few are over 80 metres, and most are residential towers of around 45 metres, around 12 floors (above ground). The city faces many similar problems as many cities around the world; it’s heavily congested, has poor air quality, with an aging infrastructure and suffers from flooding. However the city has adopted wide plan which has an integrated approach to its skyline. It has developed a clear policy in terms of location and suitability of building form and use. The plan aims to reverse many of the negative effects of its previous policies and is a significant move away from the piecemeal approach.
Do you have a favourite skyscraper?
It has to be Rafael Viñoly’s 20 Fenchurch Street. I like its bold form, its dominant presence and the way it completely modifies the climate in which it is placed.
- Julie Fulcher is an architect and CIBSE member. She works with urban climatolgist Dr Gerald Mills on the interdependent energy relationships between buildings in cities.