Definition of a Sustainable Tower

It is obvious that the definition of a sustainable tower is difficult to sum up in a few sentences, but the various perspectives on the following pages indicate a few common points that can begin to define a design brief. The National Sustainable Tower Blocks Initiative helps to understand what is socially sustainable, which is implied in design factors of the others who are mentioned.

Ken Yeang

One of the most prolific and innovative Architects currently designing sustainable towers has to be Ken Yeang of T.R. Hamzah and Yeang Architects. The practice is behind many new Eco tower designs in the Far East and as a result of their innovations they are now being asked to design these kinds of buildings throughout the world. Through the practice’s programme of research, development and design and the various books they have written, they have come up with a comprehensive analysis of the sustainable tower, which can only be touched upon in this report. 

Some of Ken Yeang’s approaches to designing eco towers or bio climatic skyscrapers are based on the following issues: 

·         The skyscraper is a necessary response to urban sprawl. Almost half of the world’s population lives in the cities, and this trend is increasing. The skyscraper has many potential economic advantages where there is minimal land use as the amount of usable space per available land area is maximised.

·         The high-rise covers less land area than a low-rise development. This will provide more green areas and reduce the impact of urban sprawl on the environment. 

·         The skyscraper can effectively address high-density development through various advantages such as reducing transportation costs, which can significantly reduce pollution.

·         All of the materials of the skyscraper can potentially be recycled during its life cycle basis.

·         It is possible to significantly decrease the energy consumption of skyscrapers through maximising natural energies and better integration of the building systems.

·         Ecological and environmental benefits can be improved by introducing vertical landscaping on buildings and linking this with the green belts in the city.  

When planning a sustainable tower the designer must access what is to be built and once that has been established then one of the main considerations is the ecological context of the site. This building will impact on immediate environment and the local environment can be utilised in design of the structure. The management of energy and materials during construction and operation will be other issues of significant importance to minimise effects on the local and global environment. 

The theories of Ken Yeang refer to a skyscraper as a system that has the following inputs and outputs. 

Input Criteria

• Amounts of energy and materials used for the system

• Rate of depletion of the energy and material resources

• The consequences of using each input ecosystem

Output Criteria

• The acceptable amounts of outputs discharged by the system

• The routes of the outputs after release and the consequences on the ecosystem

• The energy and material cost of managing the output

• The effects on the ecosystem of the management of the output

System Criteria

• The level of the pattern of needs and use

• The efficiency of the operations of the system

• The level of internalisation of the operations of the system

• The effects on the ecosystem when the system has been realised

Input Criteria

• The load capacity or extent of resilience of the natural systems in the environment

The ideas of Ken Yeang are detailed and complex but a few simple but important building design factors must be considered in the early stages of the design of a green skyscraper. These are: 

·         The position of the service cores and how this affects the overall building configuration and layout

·         The orientation of main facades and window openings (especially in relation to the climatic characteristics of the locality)

·         The façade design options (i.e. ratio of solid to glass)

·         The colour of the building envelope

·         The effects and use of vegetation and planting on the skyscraper’s built form

·         The type of expected building operational systems

·         The selection of materials and energy sources

·         The management of waste products 

Ken Yeang focus on research, development and design in the evolution of building techniques for bioclimatic towers has produced a range of new solutions and technologies. He has looked into the possible uses of rainwater and water-spray walls to induce evaporative cooling. The use of ground-level filter beds and reintroducing rain into the landscape instead of washing it down the drains are also new techniques he is developing for various projects. Other innovations include research into materials for cladding and skin. For example, structure is seen as long-life while cladding is short-life, recyclable and subject to remodelling. With new technologies, both energy performance and aesthetics can be upgraded through time.  

Ken Yeang also takes into account sociological issues in his design of Ecological Buildings. He sees the designer’s role as an innovator to help prepare society to make the right sacrifices in order to attain a sustainable future and has taken on this challenge in the design of sustainable towers. 

(Source: The Green Skyscraper by Ken Yeang, 1999 Prestel Verlag)
 

Battle McCarthy 

Battle McCarthy have been developing designs for sustainable towers for a variety of projects and have subsequently come up with a few references that will contribute to a definition of a sustainable tower.  

Sustainable strategies have evolved from the experience of designing various environmental building projects including individual homes to full urban redevelopments. These can be applied to any development including the tower. The main strategies that need to be developed are based around: energy; biodiversity; water; climate (wind, solar, air quality); waste management; vertical transportation; security; IT; and building technology. These strategies combine with the traditional concerns of building a tower including: facades, floor plate depth, cores, perimeter, servicing, substructure, etc. These factors and strategies can be integrated to create a tower that is sustainable on many levels.  

At a basic level the designers must consider external form, internal spaces and facades when planning a sustainable tower.

 External form must:

• Maximise direct solar access

• Regulate solar access

• Provide pedestrian and skycourt wind comfort

• Provide pedestrian and balcony wind safety

• Harvest energy

• Maximise air quality

• Minimise air pollution

• Protect rights to light

• Offer protection from rain or too much sun

• Regenerate the local area

Internal spaces must:

• Present high quality internal environments

• Maximise premium areas

• Minimise dead zones

• Exceed tenants’ expectations

• Be appropriate for use

• Flexible for future uses

• Optimise rental income

• Minimise construction cost

• Minimise energy consumption

• Afford views

Façades must:

• Respond according to season, time of day and orientation

• Maximise natural daylight

• Minimise artificial lighting

• Maximise solar harvest (winter)

• Maximise solar exclusion (summer)

• Maximise occupant contact with external spaces

• Capture and distribute energy

• Increase potential for natural ventilation

• Present thermal buffer (seasonal)

• Provide acoustic isolation

• Filter air

Battle McCarthy’s design objectives for sustainable design aim to: maximise human comfort; provide efficient planning; design for change and adaptability; minimise running costs and energy consumption; maximise usable space; minimise capital cost; minimise maintenance costs; protect and enhance ecological values.

The practice is at the forefront of building design and has a few projects involving sustainable towers currently in development.

HTA Architects 

HTA Architects are collaborating with Ken Yeang to develop Eco-Towers designs. Architect, Ben Derbyshire of HTA defines the Eco-Tower around the following principals:

• Tall structures can enhance urban biodiversity. An integration between human environments and animal and plant ecosystems can enrich and add merit to a site

• Successful high-density urban development must involve choice. Eco-Towers provide choice for urban dwellers who want a variety of central locations, service, transport connections and views

• Eco-Towers are embedded in a social, economic and cultural context and must give back the resources they draw from their immediate surroundings in balance with what they take

• Eco-Towers are conceived as part of a holistic and integrated design that links closely to the spatial masterplanning of the immediate environment

• Towers create powerful, formal juxtapositions in the urban cityscape and image

• The revived interest in Towers is part of an urban renaissance and symbolise renewal by repositioning and rebranding the city centre

• Increased density and availability to transportation nodes reduces carbon use. The built form of the Eco-Tower can also be energy efficient, reduce waste and reduce the cost of operation

• Eco-Towers deliver a strategy to create vibrant city living and urban density without displacing or disrupting neighbouring users

(Source: HTA Architects, www.hta-arch.co.uk)

On 4 May 2001, HTA Architects held a seminar in London called “High places: the design of green skyscrapers.” Some of the conclusions of the resulting report define an Eco-tower and identify the problems that they can address. The main points are as follows:  

• Eco towers are developing in cities around the world to deal with urban growth and migration from rural areas. They provide a way of coping with this and avoiding development on nearby arable land.

• According to United Nations data, Eco Towers can reduce transportation costs which will result in a reduction of energy consumption.

• A 'green' method implies a balanced use of organic and inorganic mechanisms in order to achieve a balanced eco-system. Designers conventionally tend to try and add on environmental features instead of utilising passive methods, which minimise the impact on the environment.

• Designs should aim to create 'cities in the sky' instead of traditional high-rise developments, which create compartmentalisation. The challenge is to design in a thoughtfully organic and humane way by integrating both horizontal and vertical aspects of the plan.

• Ecological design is still young but complex and requires comprehension of the effects that one factor will have on another.

• Due to the past experience of receiving low funding and inadequate management arrangements in the public sector, Ecological design might be unsuccessful. As a result of past experience it can be a struggle to convince tenants that innovative methods will improve their quality of life.

• Many planning authorities need to be persuaded of the advantage of developing towers.

(Source Eco Tower Seminar Proceedings www.sustainable-placemeaking.org/past040501.htm)

National Sustainable Tower Blocks Initiative 

The National Sustainable Tower Blocks Initiative is an informal grouping of several voluntary organisations in the UK, that are seeking to discover and implement ways to make Tower Blocks better and more sustainable places to live.  

The group commissioned a report that was published in February 2000. This report studies and assesses the following:

• How many tower blocks there are and what is happening with issues relating to sustainability

• Why and how tower blocks are special in terms of problems and opportunities

• What a sustainable approach could achieve

• What are the processes that improves an estate

• What are the issues to follow up

• What government links and strategies could link to the NSTBI

The work of the NSTBI is appropriate for understanding the social context of sustainability for people who live in towers. Their basic recommendations for improvement and improving the general quality of life for tenant are: continuing community development, good quality services, and an upgrading of the buildings. 

The report outlines the problems that tower block pose and came up with the following recommendations to address them: 

• Attractive tower blocks have effective security systems

• Change and improvement are dependent on successful and responsible tenant and neighbourhood management

• Attractive tower blocks have effective management

• Successful tower blocks have an allocations policy that helps build a steady and suitable population

• High-rise housing is helping to regenerate our cities and demolition of inner-city high-rise buildings should not be considered until a full assessment of refurbishment options have been considered

• There should be a more calculated approach to refurbishment in order to maximise local sustainability

• The Government should acknowledge the value of tower blocks, develop a clear policy and review current mechanisms of finance

• Local authorities and regeneration agencies should also acknowledge their value and should create more sustainable management practices

• A national network of tower block residents groups should be set up, encouraged and supported

• A more positive branding of tower blocks could be promoted with, perhaps a ‘National Tower Block Day’

The basic conclusions of the report show that the development of more sustainable tower blocks will require: 

• Appropriate systems of funding and incentives to deal with problems in tower blocks rather than demolishing them and trying to start afresh

• Suitable allocation policies that welcome people who are satisfied to live in tower blocks and will not encourage transient tenancies

• Effective security systems

• Improved social spaces and environments

• Meaningful community involvement that offers a variety of ways for residents to participate

• Satisfactory provision of services that would be based on tenant organisation

Although these results are based on experiences of social housing in the UK they can give a general indication of what requirements are necessary to make any tower socially sustainable for residential and even commercial tenants. 

(Source: ‘Streets in the Sky – Towards improving the quality of life in Tower Blocks in the UK’, Chris Church and Toby Gale, The National Tower Blocks Initiative February 2000)