16 novembro 2011

Green construction in India_by Proloy Bagchi

Green construction in India
by Proloy Bagchi_November 2011

Environmental conservation is virtually the flavour of the season.
Human intervention with nature has mounted to such an extent over the last few decades that today the progressively degrading environment has started posing a threat not only to the Planet Earth but also to the wellbeing, even survival of the human race. Waking up to the serious threat, sustainable living has become a catchword that has prompted humanity to balance its progress with preservation of the surroundings that it sustains itself in. Aware that every economic activity impinges on the natural world, humanity today has become more conscious of the need to conserve the environment. Green construction or building green buildings is a manifestation of this evolving consciousness.
Construction by the very nature of the activities it involves makes use of natural resources. Primitive man had simple and limited needs. His abode therefore had very little impact on his environment. With the civilisational evolution human needs have escalated and greater sophistication in construction has hugely impacted on nature. The growing urbanisation, especially in the developing world, is going to tap not only more and more natural resources, it also is going to impact the environment more and more around the urban areas. No wonder, therefore, the concept of green construction, which in effect means erection of buildings that are environment-friendly in all respects, has acquired greater currency. It has been estimated that as many as 10% of the buildings that are going to be constructed in the United States during the current year will be green.
According to Wikipedia, “Green construction refers to erection of a structure using processes that are environmentally responsible and resource-efficient throughout a building's life-cycle, i.e. from the stage of siting to design, construction, operation, maintenance, renovation, and demolition.” It basically involves in efficiently utilising energy, water and other resources, protecting the health of occupants and, in many cases, enhancing their productivity and, last but not the least, mitigating waste, pollution and environmental degradation.
One has, thus, to be conscious of the environment at every stage of the building process. The stage of siting a structure is as important as those that follow it. Siting is important to ensure that the building is conveniently located near facilities so that the occupants do not have to needlessly commute long distances for their day-to-day needs. Besides, siting a building near existing infrastructure, like roads, sewers and storm-water systems (where provision is not made for recycling of waste water) allows builders to lessen negative impact on a building’s surroundings.
The architectural designing has to keep in view the soil of the site in order to ensure acceptance of the required structural loads, the climate of the area to reduce the artificial cooling or heating needs, availability of water resources to determine the need for water harvesting systems and so on. In terms of climate, the building’s orientation can be aligned in different ways with the movement of the sun to reduce the need for artificial lighting or electrical cooling or heating. It can also be so oriented with the general wind direction so that the structure lets in as much fresh air as possible and reduce its carbon footprint.
Another effective way of controlling energy consumption is by making provision for green roofing. A green roof needs not very expensive surface but it manages to appreciably reduce the temperature in the building and also positively impacts on the ambient temperature. Germany and the United States have gone in for green roofing in a big way and the gardens put up on the roof not only add aesthetics to the buildings but also pull off some of the greenhouse gases from the atmosphere besides promoting bio-diverse environment in urban spaces.
Architectural design of a green building, thus, can reduce energy consumption and control even its waste. After all, most important reason today of building green is energy conservation and to reduce carbon emission levels. By facilitating use of solar energy or, wherever possible, use of other renewable sources or by the use of insulated panels appreciable amount of energy can be saved. In the United States a few of the rural houses have gone off-grid, meeting their energy-needs with the solar energy that they capture and the energy produced by biomass.
Water efficiency is another area which is an important ingredient of a green construction. Water is the fastest depleting natural resource, more so in India. Not only its consumption, therefore, needs to be controlled, its waste also is to be eliminated. Wherever feasible, provision of harvesting rain-water is necessary to supplement the supply from the water utilities. Provision for recycling waste water for watering the green areas either on ground or on the roof is necessary. The basic idea is that a green building is a “zero discharge” structure. It does not let out any waste to pollute the surroundings.
Materials-wise eco-friendly constructions are resource efficient and call for the use of green construction materials. Several local and renewable materials have developed as a response to the knowledge that buildings often have a negative impact on our environment. Architects and builders worldwide are now using construction techniques that have been developed in response to local environmental concerns and the physical resource opportunities available, coupled with modern technological refinements. These buildings range from rammed earth construction, which involves clay-based material mixed with water, to straw houses since straw is a great insulator, a breathable material that filters the air passing through it, is fire-resistant when compressed and is of low cost.
The Government of India has been pushing fly ash products as eco-friendly and durable construction material. The country has a huge accumulation of fly ash in numerous thermal power plant sites which, unless made use of, are likely to cause widespread pollution. Among the fly ash products available are cellular light-weight concrete blocks that have, inter alia, better strength-to-weight ratio, reduce dead load resulting in saving of steel & cement, reduce foundation size and provide better thermal insulation, clay fly ash bricks that have better thermal insulation, are cost-effective and environment-friendly and fly ash based polymer composites that can be used as substitute for wood. One could complement it with organic paints for an improved quality of the indoor environment.
One would tend to wonder as to why one should go in for a green construction particularly when costs of such a constructions are higher. But that is a fallacy as the cost of construction of a green building is only marginally – about 4% to 10% – higher than that of a conventional building.
At this marginally higher cost one gets benefits in different dimensions. The first dimension is environmental. Green construction enhances and protects biodiversity and ecosystems, improves air and water quality, reduces waste streams and conserves and restores natural resources. Their economic benefits are reduction in operating costs, shaping and expansion of market of green products and improvement of human productivity. The third dimension relates to social benefits which are enhancement of occupant comfort and health, minimizing strain on local infrastructure and improvement of overall quality of life.
In India green construction has been slow to catch on but there has been a distinct progress. From 6000 square metres of green spaces in 2003 they rose to 305,000 square metres in 2008. The Indian Green Building Council is promoting and fostering their construction. The first green building in India was the CII-Sohrabji Godrej Green Business Centre in Hyderabad. Kolkata’s Technopolis lays claim to be the country’s first green building for information technology which also makes money through carbon credits – about Rs. 75 lakh a year. It is the first building in the world to be registered under the United Nations Framework Convention on Climate Change as a clean development mechanism project.
Green construction can thus also be a money-earner.
Published in the inaugural issue of "Shubhalaya", a real estate periodical and reporoduced with its permission

1 comentário:

Refurbishment disse...

i read your blog so informative. thank you