Sustainable development and the construction industry

Women contribute significantly in the production of building materials

Introduction

Sustainable development could be defined as “meeting the basic needs of human beings at present without compromising the requirements for socio-economic development of future generations”. It is a process of change, whereby technological processes, instruments, natural resources, and institutional arrangements are aligned, so as to create a potential for meeting the human needs both for today and tomorrow.

The process of socio-economic development and protection of the environment are not separate challenges. The sustainability of development cannot be ensured in a climate where growth plans consistently fail to safeguard the environment and arrest the degradation of the natural-resource base and the ecosystem as a whole.

The construction industry, which plays a significant role in economic development in every country, provides, on the one hand, direct means to the development and expansion of economic activities and, on the other hand, is a major consumer of the planet’s natural resources and a polluter of the environment.

The rapid increase in the volume and complexity of construction and the resource-demanding nature of modern technologies have imposed severe stress on the biosphere. Agricultural land is often lost through urbanization and also quarrying and extraction of raw materials used in the industry. Forests and wildlands are lost through conversion to other uses. Unsustainable use of forest timber for construction purposes and firewood for manufacturing lime or brick contribute to the loss of these valuable natural assets. Similarly the excessive use of fossil fuels in the construction and building-materials industries is threatening their limited reserves and, by their combustion, is contributing to the global warming extensively.

Industrialized countries are consuming natural resources at a pace that is unsustainable in the long term. Construction industries in these countries rely mainly on energy-intensive, high-temperature process industries producing steel, aluminium, copper, glass, cement, lime, ceramic etc. Vast amounts of energy are wasted through these processes which could be used through available heat-recovery methods. These industries are also major polluters of the environment through the emissions and dust that they produce through different types of firing processes. These and many other forms of environmental degradation caused by the construction and building-materials industries are not restricted to industrialized countries. For example, the excessive dependence of the building-materials industry on the use of firewood in developing countries, while causing deforestation, adds significantly to carbon dioxide emissions and the production of “greenhouse” gases.

While increased awareness and knowledge of the implications of resource depletion and environmental degradation caused by the building-materials industry have resulted in taking some action in the industrialized countries, the developing countries, particularly in sub-Saharan Africa, have made very little progress in arresting this situation. Their position is even more desperate given that many of them are faced with fragile environments, involving aridity, decertification, flood occurrences etc.

In the light of above scenario and through, mainly, international intervention and awareness-creation over the past few years, particularly after the adoption of Agenda 21 by the United Nations Conference on Environment and Development (UNCED) in June 1992, it has become clear that if sustainable development has to be ensured for future generations, the current trends and practices of the construction sector should be controlled and managed in a way that the natural-resource base is not depleted and the environment is not degraded irrevocably. The real challenge will, however, lie in ensuring this in a sustainable manner without reducing the rate of construction activities or bringing some of them to halt. What is needed is promotion of environment-friendly, clean and energy-efficient technologies and the creation of a favourable policy climate which would stimulate the sector to implement these innovative initiatives.

Agenda 21 underscores the importance of sustainable construction industry activities as a major contributor to the sustainable human settlements development and proposes a set of action plans for governments on how to manage activities in the construction industry to ensure its sustainability. (Section G (Promoting sustainable construction industry activities) of chapter 7 (Promoting sustainable human settlements development) of Agenda 21 is given in the annex of this article.)

This article provides a brief overview of the situation of the construction and building-materials industries as far as their sustainability is concerned, and seeks to generate some awareness among the actors involved in the sector. The article touches upon three major areas of concern namely:

(a) The deterioration of the physical environment (land, forests etc.) through construction activities;

(b) The depletion of non-renewable natural resources;

(c) The contribution of construction industry activities to the atmospheric pollution.

Construction of roof with more durable materials

Interested individuals are invited to refer to the publication, Development of National Technological Capacity for Environmentally Sound Construction, which is being published by UNCHS (Habitat) and will be released shortly. This publication, which represents one of UNCHS (Habitat)’s first significant steps towards implementing the recommendation of Agenda 21, provides a detailed analys of the concerns in the above-mentioned areas and proposes a strategy for a sustainable development of the construction industry.

A. Conflicts between the construction and building-materials industries and the deterioration of the physical environment

1. Land

The continuing growth of the human population and of industrial activities related to human settlements places an increasingly heavy demand on the world’s finite resources such as land, clean water and forests. Poor management and degradation due to human activities are placing a severe stress on the resources which, in some areas, has led to serious modification or depletion of the natural environment.

A fundamental requirement of sustainable development is that the harmful side-effects of the development process, particularly of construction activities, must not exceed or overload the assimilative capacity of the biosphere, so that the process of development can be sustained. The spontaneous and, often, uncontrolled pace of human settlements development in many developing countries, and even in some industrialized countries, makes it particularly difficult to control the attendant degradation of living conditions. For example, the increasing spread of human settlements into fragile eco-zones is rapidly destabilizing natural eco-systems in many developing countries. Occurrences of floods, landslides, mudslides etc., caused by construction on delicate hillslopes, wetlands etc., testify to the vulnerability of the environment to intervention by human activities (UNCHS (Habitat)).

The highly dispersed character of construction activities in most developing countries makes it difficult to monitor the physical disruption caused by construction. There is a growing concern, in many countries, about increasing land dereliction, caused by the quarrying of sand and gravel, extraction of brick clay etc. which ultimately reduces the available land for human settlements development. The degradation of the marine environment, caused by coral mining for the production of building lime, and the disruption of wildlife habitats and watertables, by excavations etc. are now attracting the increasing attention of physical planners and coast-conservation authorities (UNCHS (Habitat)).

Traditional roofing materials

Land-use conflicts are perhaps the main threat to environment in many developing countries. These conflicts arise largely because of the lack of coordinated national land-use policies. Each sector, such as mining and forestry, views the production areas as the best resource base for their development objectives. What follows is intense competition for the same areas, without a mechanism to prioritize competing uses.

In terms of using land for quarrying and extraction of raw materials, many national policies are more concerned with licensing exploitation and charging fees for revenue-collecting purposes. They are not concerned with the appropriateness of the use to which such land is put. For example, in Kenya, many key extraction areas are gazetted as National Parks or Forest Reserves, thus, directing the conflict in favour of wildlife or forest preservation but against the agricultural sector. Many areas have been licensed for clay or stone quarrying at the expense of the agricultural/livestock sector. Most of these actions have been carried out without conceptions of environmental planning or cost-benefit analysis. When political pressures increase, then the forests are again used to settle people in preference to wildlife conservation (P. Syagga, 1993).

Appropriate land-use policies and planning specially aimed at eco-sensitive zones are very often lacking in many developing countries. One of the main reasons for the lack of clear policies is that data on which to carry out environmental impact assessment and cost-benefit analysis are seriously lacking. There is, therefore, a need to collect data and devise appropriate methodologies for objective assessments upon which priorities for land use can be based. The assignment of priorities to alternative environmental needs is not a very difficult task to undertake, however, in the ultimate, the allocation of land-use priorities would involve an economic decision as between costs and returns and safeguarding the protection of the environment. Rational decision-making and implementation of appropriate strategies, that are transparent and effective, to solve the conflicts between land use and the construction and building-materials industries are urgent requirements which should be given high priority by decision-makers in many developing countries.

2. Forest resources

Forests are an important natural-resource base in any country, playing a crucial role in the conservation of watersheds, prevention of soil erosion and balancing the eco-system. Forests are also sources of domestic wood supply, woodfuel, buildings etc. and provide habitat for wildlife. Timber, as a major forest product, is not only a very crucial building material but is also very vital to the economies of a number of developing counties. Timber-producing countries gain considerable foreign exchange by exporting timber. Therefore, any loss of forests, for any reason, may provoke potential human, economic and environmental disasters.

The construction and building-materials industries contribute to the loss of forests by converting them to other uses. That contribute to loss of forests through non-renewable use of timber, bamboo and thatching materials, and the indiscriminate use of firewood to provide energy for building-materials production.

Timber, because of its superior characteristics and almost zero-energy content, has been one of the basic building materials for centuries. It has been extensively used both as structural members for buildings and bridges and also for decorative purposes. It is estimated that in the Philippines, the demand for wood in building construction is likely to rise from 173,000 m³ in 1990 to 433,000 m³ by the year 2000. In Indonesia, the demand for wood in housing construction is likely to exceed nearly 4 million m3. Japan imports 18 million m3 of sawn wood for the 1.5 million homes annually built there. In Chile, 60 per cent of the annual production of sawn timber is used in houses and other building construction (J. O. Siopongco, 1990). These figures mean that wood is going to be an essential building material both for modern structures as well as for traditional building construction in the years to come.

However, over the past several decades, there has been increasing concern about the destruction of the tropical forests and the adverse impact of this on the environment. Inefficient commercial logging operations, the use of wood as fuel etc. have resulted in deforestation in many regions. Managing the forests in a sustainable and environmentally sound manner so as to minimize the rate of deforestation is, therefore, imperative and should be given the highest priority.

More dependable roofing structure

One way of tackling the problems associated with deforestation is encouraging the use of commercially less-accepted species (CLAS) and industrial tree plantation species (ITPS). If properly managed and exploited, these species can serve as abundant and renewable resources of building materials that can be afforded by the vast majority of the population.

There are currently no significant examples of use of CLAS and ITPS as a walling material or roof-cladding material in developing countries. In some cases the wood elements are only restricted to internal partitioning.

The use of CLAS and ITPS for construction, especially for walling purposes and as shingles for roofing, is slowly showing potential in industrially-processed wood products where the CLAS and ITPS serve as raw material. The use of wood chips, pulps and excelsior for composite boards in some countries relies on timber species which are less suitable as sawn wood due mainly to their irregular form. There is potential for using chips and excelsior from CLAS and ITPS to manufacture wood-cement boards. In some countries, where these products are on commercial sale, there is an unfavourable market trend probably due to the unatractiveness of the finish of the boards.

The Second Consultation on the Wood and Wood Products Industry, organized jointly by UNCHS (Habitat) and UNIDO and held in Vienna in January 1991, underscored the importance of greater utilization, on a sustainable basis, of wood, including CLAS and ITPS, as a renewable source of indigenous building materials in housing and construction. The Consultation, while focusing on environmentally sound management of forests, devised a set of recommendations addressing the industry, governments and the international community on ways and means for popularizing the use of CLAS and ITPS in the construction sector. (For more information refer to the report of the Consultation mentioned in the volume 1, No. 4, of the Journal.)

B. Conflicts between the construction and building-materials industries and depletion of non-renewable resources

The construction and building-materials industries are major users of the world’s non-renewable resources. Apart from their share of fossil-fuel and tropical-timber use, the construction industry is a heavy user of several metals which have limited remaining exploitable reserves, such as lead, copper and zinc. Table 1 shows some data on the consumption, base reserves and base life index of some selected metals.

Table 1. Consumption and reserves of some metals

Metal	Consumption 1990 (thousand tons)	Base reserves 1990 (million tons)	Base life Index (years)
Aluminium (bauxite)	17 878 (Al)	24 500 (bauxite)	225
Copper	10 773	550	62
Iron ore	925 000	229 000	265
Lead	5 544	120	36
Nickel	842	109	116
Tin	229	6	28
Zinc	6 973	295	40

Source: World Resources Institute, 1992.

The construction industry is responsible for the consumption of commercial energy in two principal ways: through the consumption of energy in the production of buildings and other constructed facilities, and through the consumption of energy in the subsequent use of these buildings and facilities. The energy in the production of buildings is used directly by the construction industry, whereas that consumed in buildings in use is controlled to a large extent by the eventual user. The design of buildings can also have a major impact on the intensity of subsequent energy use.

1. Embodied energy in construction

It has been found that the consumption of energy in the manufacture of building materials and components is about 75 per cent of the total energy requirement for the production of a building, the remaining 25 per cent being primarily used during on-site construction activities. However, in the context of developing countries, where construction activities are labour-intensive, the amount of energy required in construction is mainly used, in the manufacture and transporting of building materials. Therefore, economizing in the use of energy in the process of manufacturing energy-intensive building materials, such as lime, bricks, cement etc. and reducing the distance the materials need to be transported are more crucial in developing countries than in industrialized countries.

A high proportion of the energy used in the production of building materials is in a small number of key materials such as steel, cement, bricks, glass and lime. According to some analytical studies, the energy requirement for one square metre of corrugated iron sheet, fired clay tiles and fibre-concrete roofing tiles, for example, are 605, 158 and 46 megajoules respectively (UNCHS (Habitat), 1991).

Similarly, different types of construction systems (sets of materials) can result in considerable differences in the total embodied energy requirements in complete house systems. Table 2 shows a comparison of three houses in Argentina.

Table 2. Comparative energy requirements for three single-storey houses in Argentina lifetime to determine which is the optimum energy saving strategy.

House type	Embodied energy requirement (MJ/m2)
House made primarily with manufactured materials (hollow brick walls, concrete frame and roof)	1583
House made partly with manufactured materials (clay brick walls, concrete frame, steel sheet roof)	1314
House built primarily with local materials (adobe walls, timber frame, steel sheet roof)	590

Source: UNCHS (Habitat), 1991.

Because of the high energy intensities of many production processes, larger producers, using modern technologies (for example, cement producers) are aware of the need for energy efficiency. However, in the context of developing countries, where many of the producers operate at small-scale using traditional processes, it is unlikely that they can respond to changing pressure or alter established practices in a speedy manner. Any government policy should, therefore, focus on assisting the small-scale sector in upgrading its production technologies so as to economize on the use of energy in its daily operations. Such policies should include, among others:

a) Careful study and improvement of kiln operations;
b) Use of cheaper or non-premium fuels such as agricultural waste;
c) Use of solar energy and heat recovery devises in the kilns;
d) Reduction of transporting distances by decentralized production;
e) Use of recycled materials.

In addition to the methods and techniques for improving the energy efficiency of the production of building materials there is a major opportunity available by which to reduce the embodied energy of buildings; the appropriate choice of materials and design. Some strategies that designers can follow include:

a) Use of low-energy content materials;

b) Selection of lower energy structural systems, such as load-bearing masonry walls in place of reinforced concrete or steel frames;

c) Design of low-rise buildings;

d) Design for the use of materials, which are found near the site;

e) Use of, where possible, waste or recycled materials.

These strategies will not always be consistent with strategies for saving energy consumption in buildings. It is advisable to examine the total energy consumption over a building’s

Low-energy building materials

2. Energy in buildings in use

Energy is used in buildings for cooking, space-heating and cooling, and lighting and for productive activities. Studies show that in areas where there is a substantial annual heating requirement, coal-burning stoves are often used in urban housing: insulation standards in such housing are frequently very poor by comparison with those of industrialized countries, and the combustion products add considerably to urban air pollution. In areas where the primary need is for cooling, there is an increasing demand for air-conditioning in workplaces and upper-income urban households. Air-conditioning is inherently energy-intensive in relation to the cooling achieved: the poor insulation and sealing of many air-conditioned spaces add to the energy demand.

The use of improved insulation techniques for buildings and “passive solar” design approaches to reduce heating loads and/or eliminate the need for mechanical ventilation and air-conditioning are potential considerations for energy saving in buildings in use. Thus, strategies for greater utilization of these techniques must be formulated and enforced. In this regard, education of the designers, public awareness, demonstration buildings, revision of regulation etc. could be among the various tools and means to utilize this potential resulting in economy in energy use in buildings.

C. Contribution of the construction industry to atmospheric pollution

Pollution caused by construction and building-material-production activities include water pollutants from quarrying activities and effluents from chemicals, particulates from fuel combustion and manufacturing processes, carbon oxides (CO and CO₂) from burning fuel, sulphur dioxide (SO₂) and nitrogen oxide (NO and NO₂) from high temperature burning, and hydrocarbons from the manufacture of chemicals and allied products such as paints.

At the local scale, the construction and building-materials industries create air pollution through emissions of dust, fibre, particles and toxic gases from site activities and building-material-production processes. They contribute to regional pollution through emissions of nitrogen and sulphur oxides in building-materials production, and they contribute to pollution on a global scale in two important ways: (a) by the use and release of chlorofluorocarbons (CFCs) in buildings contributing to the depletion of the atmospheric ozone layer, and (b) by the emission of carbon dioxide and other “greenhouse gases”.

Table 3 shows the annual carbon dioxide emissions from fossil fuel consumption and cement manufacture for four selected countries.

Table 3. Carbon dioxide emissions for selected countries, 1989, and the estimated contribution from construction, cement manufacture, and building use

Country	Total CO2 production (thousand tons)	Estimated proportion of CO2 output (percentage)
		Construction industry	Cement manufacture	Building use
Argentina	118 157	7.6	1.9	39
India	651 936	17.5	3.2	18
Germany	641 398	11.8	2.1	51
Kenya	5 192	11.9	11.7	25

Sources: World Resources Institute, 1992; and Wells, 1986.

An estimated 8 to 20 per cent of these emissions in different countries are due to construction and building-material-production activities, and a further 2.5 per cent globally results form the chemical reactions taking place in cement and lime production. World carbon dioxide emissions from fossil-fuel consumption and cement manufacture increased nearly four-fold from 6000 tons per year in 1950 to 22,000 tons in 1989 (Spence, 1993). A further enormous contribution to global emissions results from the energy consumption of buildings in use, up to as high as 50 per cent in northern industrialized countries (Spence, 1993).

Organic compounds, such as methane, make a considerable contribution to the greenhouse effect. A particular concern is felt in regard to CFCs used in insulation materials, in fire-extinguishing systems and in air-conditioners. Although the volumes of CFC emissions are low, they have a disproportionally high impact on climate.

Table 4 indicates the relative contribution made by the principal gases.

Table 4. Contribution to greenhouse warming by various gases

Gas	Contribution to warming (percentage)
Carbon dioxide	50
Methane	19
CFCs	17
Tropospheric ozone	8
Nitrous oxide	4

Source: Henderson and Shorrok, 1990.

Use of materials found near the construction site

As discussed in preceding paragraphs, most of the pollution resulting from building-material-production processes is the result of fossil-fuel burning. Therefore, the principal means of reducing pollution would be through increased energy efficiency in all activities. The transporting of materials is also major factor in contributing to the air pollution. Reducing the transporting requirements by decentralized production facilities will significantly reduce these emissions.

D. Concluding remarks

Previous sections have established that construction activities are causing, or contributing significantly to, many of the present processes of deterioration of the natural environment, in particular to:

· Loss of soil and agricultural land;
· Loss of forests, woodlands and wildlands;
· Increases in freshwater and coastal pollution;
· Increases in atmospheric pollution at local, regional and global scales;
· Depletion of the Earth’s non-renewable resources.

But continued and increasing levels of construction activity are essential to all aspects of development; and indeed only by raising living standards generally will it be possible to reduce or eliminate many of the currently most serious types of environmental deterioration. Poverty is one of the principal causes of both rapid population growth and land degradation and loss of tropical forests.

To ensure a sustainable future, it is, therefore, neither feasible nor desirable for the total level of construction activity overall to be restricted, although in the industrialized countries there may be strong arguments for reducing activity by re-using existing buildings rather than building new ones. In other cases, it is difficult to conceive of construction activity which does not result in some irreversible changes in the natural environment. Yet sustainable development does not need to imply a complete halt to irreversible change in the natural environment. Economists argue that one essential aspect of sustainable development is that the world’s total stock of “capital”, natural plus human-created capital, should not diminish over time.

Some conversion of natural into human-created capital is clearly acceptable within this definition. Construction of a dam, for example, reduces the existing natural capital of the region in many ways - through forest clearance, quarrying of construction materials, changes in water run-offs and sediment loads, changes in human and wildlife habitats and other ways - but it also creates a lasting asset, which can provide power, irrigation water and other benefits for the immediate future and, if well-designed, for a long time into the future. Similarly, the construction of housing and other buildings uses natural capital - through quarrying, land-conversion, the creation of atmospheric pollution and so on - but compensates for this by increasing the stock of human-created capital which will be passed on to future generations. The materials of which these fixed-capital assets are made are still available, though in a less useful form, for re-use in the future. Thus, human-created capital is intended to compensate for the loss of natural capital.

Given the nature of the construction industry, which is fragmented, multisectoral and rather complex in character, changes cannot be expected to happen in a speedy manner. However, all initiatives will involve change in technology, commitment towards preserving the natural resources, mitigating environmental degradation, and special investment programmes within the industry: but many of these inputs are unlikely to come about without a necessary stimulus from outside the industry. Therefore, communities, local and national governments, decision-makers, international agencies and any other actor involved in the construction sector should be committed to taking such measures as would ensure the sustainability of construction activities, so leading to sustainable social and economic development in all countries.

References

L. Henderson and L. D. Shorrok, Greenhouse Gas Emissions and Buildings in the United Kingdom, BRE Information paper 2/90 (Garston, Building Research Establishment, 1990).

J. O. Siopongco, “Greater utilization on a sustainable basis of wood including CLAS and plantation species as a source of indigenous low-cost building materials in housing and construction” (unpublished report prepared for UNCHS (Habitat), 1990).

P. Syagga, “Promoting sustainable construction industry activities in the African region” (unpublished report prepared for UNCHS (Habitat), February 1993).

UNCHS (Habitat), Energy for Building (Nairobi, 1991) (HS/250/91E).

UNCHS (Habitat), People, Settlements, Environment and Development (Nairobi, 1991).

J. Wells, The Construction Industry in Developing Countries (1986).

World Resources Report (World Resources Institute, 1992).

Annex
PROMOTING SUSTAINABLE CONSTRUCTION INDUSTRY ACTIVITIES

Basis for action

The activities of the construction sector are vital to the achievement of the national socio-economic development goals of providing shelter, infrastructure and employment. However, they can be a major source of environmental damage through depletion of the natural-resource base, degradation of fragile eco-zones, chemical pollution and the use of building materials harmful to human health.

Objectives

The objectives, are, first, to adopt policies and technologies and to exchange information on them in order to enable the construction sector to meet human settlements development goals, while avoiding harmful side-effects on human health and on the biosphere, and, secondly, to enhance the employment-generation capacity of the construction sector. Governments should work in close collaboration with the private sector in achieving these objectives.

Activities

All countries should, as appropriate and in accordance with national plans, objectives and priorities:

(a) Establish and strengthen indigenous building-materials industry based, as much as possible, on inputs of locally-available natural resources;

(b) Formulate programmes to enhance the utilization of local materials by the construction sector by expanding technical support and incentive schemes for increasing the capabilities and economic viability of small-scale and informal operatives which make use of these materials and traditional construction techniques;

(c) Adopt standards and other regulatory measures which promote the increased use of energy-efficient designs and technologies and sustainable utilization of natural resources in an economically and environmentally appropriate way;

(d) Formulate appropriate land-use policies and introduce planning regulations specially aimed at the protection of eco-sensitive zones against physical disruption by construction and construction-related activities;

(e) Promote the use of labour-intensive construction and maintenance technologies which generate employment in the construction sector for the underemployed labour force found in most large cities, while at the same time promoting the development of skills in the construction sector;

(f) Develop policies and practices to reach the informal sector and self-help housing builders by adopting measures to increase the affordability of building materials on the part of the urban and rural poor through inter alia credit schemes and bulk procurement of building materials for sale to small-scale builders and communities.

All countries should:

(a) Promote the free exchange of information on the entire range of environmental and health aspects of construction, including the development and dissemination of databases on the adverse environmental effects of building materials through the collaborative efforts of the private and public sectors;

(b) Promote the development an dissemination of databases on the adverse environmental and health effects of building materials and introduce legislation and financial incentives to promote recycling of energy-intensive materials in the construction industry and conservation of waste energy in building-materials production methods;

(c) Promote the use of economic instruments, such as product charges, to discourage the use of construction materials and products that create pollution during their life cycle;

(d) Promote information exchange and appropriate technology transfer among all countries, with particular attention to developing countries, for resource management in construction, especially for non-renewable resources;

(e) Promote research in construction industries and related activities, and establish and strengthen institutions in this sector.

Means of implementation

(a) Financing and cost evaluation

It is roughly estimated that the construction activities of developing countries amount to about US$400 billion annually and will increase by about US$20 billion annually. The stream of new investments for these levels of activity and to bring in clean technologies is estimated at US$40 billion annually, primarily from private sources. If 10 per cent of the new investments come from the international community, this would amount to US$4 billion annually. About US$3 million would be needed to strengthen international organizations.

(b) Human resource development and capacity-building

Developing countries should be assisted by international support and funding agencies in upgrading the technical and managerial capacities of the small entrepreneur and the vocational skills of operatives and supervisors in the building-materials industry using a variety of training methods. These countries should also be assisted in developing programmes to encourage the use of non-waste and clean technologies through appropriate transfer of technology.

General education programme should be developed in all countries, as appropriate, to increase builder awareness of available sustainable technologies.

Local authorities are called upon to play a pioneering role in promoting the increased use of environmentally sound building materials and construction technologies, e.g., by pursuing an innovative procurement policy.