Financial Times

Towards sustainable development - an overview

By Chitra Weddikkara, Department of Management, Construction and Building Sciences, University of Western Sydney, Hawkesbury, New South Wales, Australia

In recent years built-environment professionals in Sri Lanka have commenced addressing sustainability issues both academically as well as in practice.

The Sri Jayawardanapura, Kotte, parliament has traditional forms of roofs and its design provides natural ventilation and shade. (Library picture)

Many papers have been presented at forums such as the public affair forums of the annual sessions of the Institute of Architects on the theme 'Architecture in Harmony with Nature'. Studies have been undertaken by the academics and the students of architecture in the Department of Architecture at the University of Moratuwa.

Some of the research undertaken were, the use of appropriate materials for construction, use of energy during construction, the response of the built structures to the existing social order.

Further studies were undertaken on comfort levels in different types of dwellings, so as to evaluate the most comfortable levels of humidity and ventilation. It was found that the traditional house with porous mud walls and steep side opened thatch roof to be the most thermally comfortable dwelling.

The knowledge gained from these various studies have been used in the teaching of the undergraduates of the built environment in the Faculty of Architecture to make the students aware of sustainability issues.

Some of the research undertaken also led to analysing the traditional or vernacular architecture that existed in the past, what happened to these traditions, what was the present and what was the future, so that these best practices could be used by the future built environment professionals.

Vernacular architecture

Sri Lanka has had long architectural traditions dating back, from the ancient kings, to the Portuguese, Dutch and the British period. The architectural traditions in Sri Lanka were an amalgamation of various influences such as the influence of Buddhism from India and building methods from the Mediterranean brought by Muslims and Arab traders, with modifications by the Dutch and British.

With this coexisted the indigenous building structures constructed from mud or wattle and daub, brick, coconut and thatch.

This indigenous tradition was motivated and determined by the internal conditions within the country from factors such as culture and religion. Some elements of this architectural tradition include the roof which was a great umbrella roof that had a number of variations.

The other elements were the human scale and the basal platform. The use of site selection, material selection, use of natural light and ventilation and climatic responsibility were some of the characteristics of this traditional or vernacular architecture. In short, the traditional Sri Lankan architecture was an eco-sensitive architecture following the green architecture principles.

However, these traditional principles were abandoned due to various influences and complex needs of people and attitudes thus influencing the contemporary architecture existing today posing much problems in the built environment.

The modern user today demands the use of modern materials such as glass and aluminium, air conditioning instead of natural ventilation.

Therefore the contemporary trends in Sri Lanka have changed from the traditional solutions thus affecting the built environment of the country. This effect was mainly seen after British occupation, mostly influenced by the colonial education, economic and administrative background, technologies and material being introduced during this era. Therefore the traditional architecture that served the people's needs at that time changed and the contemporary architectural practices sustained these needs.

Today many young architectural practices are moving towards green architecture, following the green principles such as energy conservation, working with the climate, minimising new resources, respect for uses, respect for site, waste management, including green thinking into building regulations and most importantly a holistic approach to design. Some of the examples where elements of green principles have been used in Sri Lankan building have been identified below.

The national library building, Colombo - this building is designed as a series of open trays under a large umbrella with the projecting roofs in each floor giving the umbrella effect. By this arrangement each floor was protected by the overhanging roof above also giving the possibility of natural ventilation.

This building design in some ways addressed the issue of natural ventilation. This is a primary requirement in a hot and humid country, thus allowing only minimum requirements for artificial ventilation.

Parliament building in Sri-Jayawardanapura, Kotte - this building used the traditional forms of roofs, local material, and relied on natural ventilation and shading for comfort conditions in the building.

Audience hall in the Kandyan Art Association, Kandy - this building too used the principle of naturally ventilating the building rather than the use of artificial ventilation.

The roof was constructed using timber frame work and the roof covering with clay tiles harmonising with the external lake surroundings where the building was situated.

Union Assurance building, Colpetty - this building built in the city, even though a very modern building, artificially ventilated, attempted using the land form in such a way to reduce the curtain walls facing the sun directly, thereby reducing the amount of energy used in air-conditioning.

Further reflective glass was used for curtain walls to further enhance this effect.

Kandalama Hotel, Kandalama - one of the architects that have played a major role in eco-sensitive architecture in Sri-Lanka is Geoffrey Bawa. He has shown how buildings could be responsive to the fragile ecology and be sensitive and meaningful. Such a project is the Kandalama Hotel.

While its location overlooking the ancient Kandalama reservoir is contestable, this building is a flat roofed building several stories high and has been concentrated on the least possible ground area, with natural landscape, without disturbing the natural flow of rain water and the growth of vegetation.

The flat roofs with natural endemic vegetation attempts to maintain the thermal balance of the building. The existing rock formations have dictated the shape of the cave like entrance and the rock walled tunnel leads to the reception and to the main public lounges. The elemental forms such as the structural elements, maintains the natural lines of the rocky outcrop. Any building is essentially an intrusion on the environment. However, Bawa overcomes this paradox by creating an architecture that rises from the environment.

Low energy architecture

Energy efficient buildings and sustainability are inter-related. Both safeguard the environment and the process of exploitation of resources and attempts to be in harmony with technological change so as to be able to maintain the current and the future potential to meet human needs.

According to the Ceylon Electricity Board, the lighting in commercial buildings account for 20% of the total electricity consumption while residential accounts for 35%.

It has been estimated that the use of energy is 20% - 60% in the annual operations and maintenance cost of commercial buildings. Therefore improving energy usage of such buildings could provide the user savings in annual expenditure. The demand for electricity for lighting is expected to grow in Sri Lanka, with the expected increase in the population. In this process the use of energy efficient building systems harnessing maximum natural light will lead to energy savings each year. In Sri Lanka, day lighting is available in abundance with approximately 250 -300 clear sunny days receiving 4-7kwh of solar radiation per sq.m. Efficient planning to accommodate this would result in considerable savings in energy.

Day-lighting is considered a renewable non polluting source of light and this should be desired in Sri Lankan buildings. The use of energy in the housing and commercial sector in Sri Lanka is still on the increase.

However, in the last few years there has been conscious effort by most architectural practitioners to provide natural lighting and ventilation, mostly in the housing sector. But in the commercial sector this has been a slow process.

The initiative taken by the Sri Lanka Energy Managers' Association to give an award for the best designed energy efficient building is an incentive towards this direction.

The CEB in association with the private electric company namely LECO has jointly promoted less consumption of energy by providing up to four compact fluorescent lamps (CFL) per household.

CEB pays the supplier up front, and recovers the cost of the bulbs from the consumers in 12 monthly instalments. This way the capital cost burden to a small household is minimised. Some of the barriers in the market includes no tax benefits for the local manufactures to make the bulbs locally.

At present the emphasis is only on generation of electricity rather than conservation and there is still little incentives for conservation. If energy efficient practices are to be sustained it is important that the relevant authorities be interested in the conservation as well as generation of energy.

The housing developments in the past have had both positive and negative impacts on our eco-systems.

The major housing programmes fell under three categories - programmes with direct intervention by the state in planning and construction, programmes implemented by the state with user participation and housing loan programmes with minimum intervention in planning and construction.

Under the first two categories the government had the opportunity to do the overall planning both at programme level and at the project level and there was scope for the state to look at the aspects of eco-sensitive housing development. However, most of the large housing projects that came under the first category were located closer to Colombo's municipal limits or suburban areas. Some were located in the low lying areas due to political intervention.

Even though some aspects of eco-sensitiveness were looked into, one of the main adverse effects of these projects was flooding of the areas due to filling of these low lying areas and the blocking of natural drainage patterns. While there was some ill effects due to unplanned over ambitious housing programmes, some positive efforts were made by the state sector towards public housing. In order to encourage building of houses using traditional materials and technology inherent to different regions in the country, a national low cost housing competition was conducted annually to increase the awareness and interest within the communities. The efforts have been successful and the result has been well planned houses using locally available materials such as wattle and daub, sun dried brick, stabilised mud walls, stone walling and for the roof the use of thatch, straw and country tiles with a conscientious effort to plan out home gardens with proper surface water drainage. This has encouraged the communities to revert to traditional solutions. The houses constructed country wide under this programme have had the least damage to the eco-system.

Sustainable construction

Sustainable construction involves management of the environment during the life cycle of the product, that is from its conceptual stage to the ultimate demolition stage. In the case of construction, the product could be a building, civil engineering project or infrastructure development work.

The trends in sustainable construction can be grouped under energy resources and land use issues. Where operation energy is concerned there are trends to move towards greater use of natural ventilation and lighting to supplement energy intensive artificial methods by the built environment professionals. Where embodied energy is concerned studies are under way to compare materials on the basis of energy inputs.

The use of non-renewable bio-mass energy in brick and tile production is of particular concern. The extraction of river sand and coral lime that is used in construction has had severe environmental impacts, especially in the coastal zone; substitutes for these such as offshore sand and dolomite lime are being either considered or encouraged.

The use of timber in construction has severely reduced the country's forest cover; some efforts have been made to replace timber elements in building with precast concrete. Studies have also been undertaken on the extent of waste on building construction sites by academics in the civil engineering department of the University of Moratuwa. Land use planning is rather haphazard at present and unplanned development has reduced agricultural productivity and affected natural drainage in the marshes. However, a mechanism for ensuring the restoration of borrow pits resulting from clay mining has been introduced recently. Bodies such as the Urban Development Authority are in the process of implementing land use planning regulations, such as by preventing the filling of critical wetland and flood retention areas.

In general, the best practices in sustainable construction have been in the low cost housing sector. The use of virtually zero energy compressed soil blocks and boron treated wood for roofs. The hotel sector too has adopted some good practices such as recycling of waste and the use of solar water heating in their operations.

In terms of inputs to the construction process regulations are under way to maintain the quality standards when these materials are supplied to the site as well as when the process is taking place to achieve the final product. Sri Lankan contractors, particularly those belonging to the higher registration categories, have become more and more conscious about maintaining quality levels in construction. A statistical analysis is under way to see how health, safety rules, material storage and handling, usage of material and wastage are being done so that improvements could be made to be in line with international standards.

If some of the conscientious efforts made by various sectors in Sri Lanka towards sustainable development are to continue it is important that the development of indigenous and inexpensive technologies be an important objective of any large corporate client.

Furthermore, built environment professionals must take responsible decisions towards conservation of the ecology through eco-sensitive architecture, while having a clear look at the process of construction thereby changing the linear process of construction to that of a cyclical process leading to significant use of recycled, renewed and reused resources with a significant decrease in the consumption of energy and resources. In short all human activity, including building activity, should conserve the environment.