Role of construction industry in climate change

The construction industry is one of the major sources of pollution. Construction-related activities account for quite a large portion of CO2 emissions. Contribution of the building industry to global warming can no longer be ignored. Modern buildings consume energy in a number of ways. Energy consumption in buildings occurs in five phases. The first phase corresponds to the manufacturing of building materials and components, which is termed as embodied energy. The second and third phases correspond to the energy used to transport materials from production plants to the building site and the energy used in the actual construction of the building, which is respectively referred to as grey energy and induced energy. Fourthly, energy is consumed at the operational phase, which corresponds to the running of the building when it is occupied. Finally, energy is consumed in the demolition process of buildings as well as in the recycling of their

parts, when this is promoted3. We have found that the cost-effective and alternate construction technologies, which apart from reducing cost of construction by reduction of quantity of building materials through improved and innovative techniques or use of alternate low-energy consuming materials, can play a great role in reduction of CO2 emission and thus help in the protection of the environment.

Cost-effective construction technologies in India

It indicates that by careful selection of materials and technologies in order to reduce consumption, it is possible to significantly reduce emissions. Let us browse through some of the available and usable technologies in India, which have proven to be successful after years of trial by scientists, engineers and architects from different parts of the country. There may be more such technologies, since India is a country of diversity and rich cultural and architectural heritage. It may be noted that cost-effective construction technologies do not compromise with the safety and security of the buildings and mostly follow the prevailing building codes. The most popular ones have been discussed here.

Use of cost-effective technologies in India – Reduction in GHG emission and cost of construction

As already mentioned, there are other improved alternate technologies available like bamboo panels, bamboo reinforced concrete, masonry stub foundation, etc. All of them can contribute significantly, if not more, in reducing in the cost of construction and CO2 emission. For academic purpose, this article restricts discussion to rat-trap bond wall, brick arches and filler slabs only, for which data on material consumption and reduction from conventional techniques are readily available. By adopting the techniques mentioned above, a reduction of 20% can be achieved in the cost of construction without compromising on the safety, durability and aesthetic aspect of the buildings

In 2006, the cost of structural work for a building with ordinary masonrywall and slab in India was to the tune of Rs 3000 persq. m. It may vary by 15–25% depending upon the locationand availability of materials. A 20% saving in cost means reduction by Rs 600 per sq. m and for a 50 sq. m residential house, the saving will be to the tune of Rs 30,000. The figures given in Table 2, when related to the Table 1 show reduction in CO2 emission for a 50 sq. m building. The above reduction of 2.4 t in CO2 may qualify for carbon trading also and according to the current rate of trading may fetch a minimum of Rs 1800 also. (Experts feel that though subject to wide fluctuations, the going rate of one Carbon Emission Reduction (CER) unit in the European market is around 12–13 Euros. One Euro is now equivalent to Rs 57.43.) In case of houses made of compressed mud block, reduction in CO2 emission would be to the tune of 8000 kg or 8 t per 50 sq. m of the house.

Source - http://www.ias.ac.in/currsci/jan102008/38.pdf