The following section offers a brief summary of the impact of humans and their buildings on the natural and built environments. These impacts are cross-referenced to the triple bottom line themes, sub-themes and indicators used for the design guidelines.

The pursuit of sustainable development brings the construction industry, and specifically the building industry component thereof, into sharp relief. The built environment is a major component of contemporary life. Almost half the world’s population (47,2%)[20] is now urbanised and by 2050 that proportion will have reached two-thirds. The urban population of the United Kingdom is already at 89,5 percent.

Construction constitutes more than half of total national capital investment in most countries, and construction can amount to as much as 10 percent of GDP. It is estimated that the industry employs about 111 million people globally, and accounting for almost 28 percent of all industrial employment, is the biggest industrial employer worldwide. Construction accounts for 7 percent of total employment with 75 percent of all construction workers found in developing countries. Typically over 90 percent of workers are employed in micro firms with less than 10 persons[22].    

In fact, internationally, small and medium-sized enterprises (SMEs) constitute 97 percent of all construction firms globally, with 95 percent of firms being micro firms having ten or less employees. This is equally true of the developed countries: even in France and Germany there are fewer than ten large national contracting firms having thousands of employees.

The industry has a significant multiplier effect on the economy as a whole and it is considered that one job in construction gives rise to two further jobs[23] elsewhere in the construction sector and other sectors of the economy. As much as 20 percent of all employment can be ascribed to construction activities in some way on this basis. Buildings and structures form and alter the nature, function and appearance of the natural and built environment: it impacts on rural areas, villages, towns and cities. Buildings are known to have a long life: many of the buildings still in use around the world are many hundreds of years old. Their construction, operation, repair and maintenance and demolition consume energy and resources and generate waste in excess of any other industrial sector. Construction activity is a consumer of materials and scarce resources (water and energy), is a significant contributor to global warming emissions (including CO² from the burning of fossil fuels), contributes to air pollution (smoke and dust pollution), generates vast quantities of waste, contaminates the soil, and destroys existing vegetation.

Yet buildings are a crucial part of governments’ strategy to improve the quality of life: buildings constitute the infrastructure through which health care, education and housing are provided. The economic, social and environmental benefits that may result from a more efficient and sustainability-led industry are not difficult to imagine. The following graph shows the environmental impact of buildings in the USA as a percentage of US nationwide annual impact. Achieving a 10-20 percent reduction in consumption and waste patterns will have a significant and ongoing societal benefit.

Building activity varies significantly between developed and developing countries: whereas more of the building work in developed countries is orientated around renovation and maintenance (33 percent and rising in Europe), activity in developing countries has more to do with new construction. Both activities must recognise that buildings are a resource that must be adapted rather than demolished.

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12.1 Economics

The economic performance of a building has traditionally been perceived as the initial costs of its development and its return over a fixed period of time. However, current thinking includes other costs and opportunities, such as human and SMME development, life cycle costs, material costs and impacts, energy costs, waste generation and removal costs, transportation costs and impacts, and efficiency costs.

12.1.1 Small, Medium and Micro Enterprise Development

Given the economic structure of the global industry and the ability of SMME development to overcome poverty, construction is one industry most able to enhance SMME development. Efforts are therefore focussed on increasing the participation of SMMEs in both the construction and subsequent maintenance of buildings

12.1.2 Life Cycle Assessment

Life Cycle Assessment (LCA) methodologies are increasingly used to improve environmental performance for products and for construction works. One must not assess construction products on a stand-alone basis because some products may use materials with an initially relatively high environmental load which however significantly offset that load over the life cycle of the building. Construction products must be assessed in terms of their performance throughout the lifetime of the construction works and what happens to them when deconstruction or demolition takes place

The Rocky Mountain Institute believes that a fourfold improvement in productivity can be achieved without consuming further resources. This will require the use of leaner technologies, greater use of recycling, better design and improved management.

12.2.2 Energy

Buildings in use, including the embodied energy from manufacture, account for almost 40 percent of all energy end-use, a figure consistent with other developed economies.

An analysis of building sector consumption as shown in Figure 2 below clearly illustrates the very real opportunities for reducing energy consumption and greenhouse gas emissions that exist through considered design. For example, the energy used for space heating and cooling, water heating and lighting accounts for 64 percent of the energy used.



Figure 2 provides a breakdown of residential usage while Figure 3 is for commercial buildings. The figure for space heating will alter relative to the different climatic conditions of the development: however, achieving a comfortable indoor temperature – be it heating, chilling or humidity removal – will still account for the highest single use of domestic energy. Designing with this in mind will substantially reduce this figure. It must also be remembered that it is the user who pays for this consumption - $1,291 per household in the USA in 1995 – so that any reduction in energy consumption directly benefits the household. Energy consumption reductions of up to 82 percent have been recorded in new, 5-bedroom houses in the USA indicating the order of savings possible to citizens.

Achieving a comfortable working environment once again rates as a substantial user of energy. However, what is far more disturbing is the abnormally high rate of energy use for lighting, particularly given the low-energy fittings available. Other than those buildings that are used at night, it is difficult to understand why such exorbitant energy use is necessary for lighting.

Regional and Local Authorities facing severe energy shortages are already introducing building codes to improve energy efficiency.



New York energy consumers are expected to save up to $80 million per year in energy costs as a result of a new building code requiring the use of updated technologies and enhanced energy conservation requirements for residential and commercial buildings.

The new technologies include such items as more efficient thermostats, power transformers and fireplaces. It is estimated that the code will result in a reduction of carbon dioxide emissions of 517,000 tons per year, roughly the equivalent of removing 104,000 cars from the state’s roads. This initiative clearly indicates the impact that the use of appropriate technologies within the construction industry can have.

It must be borne in mind that energy use in developing countries will overtake that of industrialised countries by 2020 and account for 75 percent of the global energy consumption increase between now and 2050. It is therefore imperative that developing countries be encouraged to employ the new technologies sooner rather than later.

12.2.3 Waste Generation

Apart from accounting for almost 50 percent of all materials extracted, these same materials constitute some 50 percent of all waste generated prior to recycling or reuse or final disposal. In the United Kingdom, some 70 million tonnes of construction and demolition materials and soil end up as waste[25]. Some 13 million tonnes of that waste is made up of materials delivered to sites and discarded unused. Construction waste has emerged as a larger waste stream than demolition waste and constitutes the largest waste stream by weight in the EU. Disposing of these waste materials is presenting increased difficulties in many parts of the world. Increased emphasis needs to be placed on waste minimisation through the use of such strategies as waste-prevention planning and design, recovery-orientated construction, reparability (design for disassembly and repair in the factory) and recyclables (used products to be returned to their producer) and reuse.

Significant opportunity exists to recycle and reuse construction and demolition waste as aggregates in road construction for sub-base layers in concrete. Several countries are recycling up to 85 percent in this way.

The European Parliament has approved a packaging directive that will oblige countries to recycle 55 percent of glass, paper, cardboard, metals and plastics by 31 December 2008. The consequence of this directive is that doorstep recycling will have to be done in every local authority, if not in every household in every country.

12.2.4 Transportation

Compact towns and cities that are well-served by public transport systems are appreciably more energy efficient than cities that have a relatively low urban density displayed as urban sprawl. The continued reliance on fossil fuels as the primary energy source requires that we develop compact urban settlements that do not demand automobile use in order to access the social infrastructure.

12.2.5 Efficiency of Use

The quality and efficient operation of buildings and infrastructure are fundamental to achieving urban sustainability.

Sourced:
An Architect's Guide to Designing for Sustainability
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