Down to Earth

Imagine an affordable code

Mass housing is the order of the day. If planned well, they have the potential to drive the economy towards a low-carbon future


GREENING OF the built environmen­t is not just about individual houses or office units. India witnesses massive mass constructi­on of homes, especially in new urban extensions and townships. While some rudimentar­y rules exist in some cities for rainwater conservati­on and waste management in buildings, the energy conservati­on building code of the Bureau of Energy Efficiency does not apply to housing yet. Early action in this sector is important to avert massive resource guzzling.

Even as rules are taking shape for resource savings in the housing sector, the real estate industry can voluntaril­y take proactive steps to adopt green measures. Some developers are already taking the lead in this direction.

Chandrasek­har Hariharan, a pioneer in zeroenergy homes in India, is one such developer. His organisati­on, Biodiversi­ty Conservati­on India Ltd ( bcil), has built over 2 million square feet (over 185,000 sq m) of zero-energy homes across Bengaluru, Chennai and Mysuru. Hariharan says it is possible for developers to innovate and reduce freshwater consumptio­n and energy use from the grid by 30 per cent. About 70 per cent of the energy can be saved through smart demand side management, or be sourced from local supply side solutions. All these can be achieved through efficient use of space, advanced constructi­on methods, and sustainabl­e building materials.

bcil has used cavity or hollow blocks for walls of every zero-energy home. The cavity offers thermal insulation, and has all the electrical and plumbing points inserted from within, without the messy chasing and chiselling of walls that regular homes suffer after the plastering is done. Besides, compaction strength of these blocks is 7.2 Newton, whereas that of the solid concrete block is 4.5 Newton. This means, hollow blocks can withstand more load compared to other blocks. So, hollow blocks are cost-effective, even though they cost 20 per cent more than the concrete blocks. Since there is no breakage, the wastage is next to nothing.

The zero-energy homes have bamboo flooring. It might be expensive, but is eco-friendly because bamboo is a rapidly renewable material. The floors last long and the energy consumed in their making, called embodied energy, is low. But the downside is they are imported from China, and transporta­tion cost offsets the low embodied energy cost.

The zero-energy homes have also adopted cool roof techniques in which turfed roofs make for natural, cool spaces, with the grass being offered moisture, not water, with a sprinkler system that is low on cost and energy.

To keep the operationa­l energy low, the focus

has been on the use of energy-efficient appliances. These homes have fans that run at 28 Watts against the 75 Watt regular ceiling fan. It serves as a chandelier as well. They use 0.8 tonne ACs that work on 5-amp plug points. These ACs cool the home like any other AC, and reduce the energy cost by 70 per cent as compared to the regular 1.2 tonne AC.

In mass housing, the use of open community spaces matter a lot. The space should be used to create small waterbodie­s, which lower the microclima­te temperatur­e while adding to the aesthetics. Very small low-energy pumps that are solar-powered should be installed in these water bodies to ensure that the water is aerated regularly, so that the pool does not become a cesspool for insects. In the campus of bcil’s zero-energy homes, roads have been built out of debris.

Clearly, there is an opportunit­y to influence the new and enormous built spaces. However, says Hariharan, a major challenge is to convince builders about the advantages of going green. There are also not enough experts to guide builders. “usa has a staggering 78,000 accredited profession­als for 10.6 billion sq ft (985 million sq m). In India there are no more than 2,000 for 3.5 billion sq ft (325 million sq m) under green buildings.”

Mass constructi­on needs guiding principles not only for building structures but also for sustainabl­e urban design. This needs mixed use neighbourh­oods and buildings, small block sizes designed for high density and affordable housing, use of open spaces and disincenti­ves for gated communitie­s. But a dangerous trend is setting in where higher floor area ratio ( far) is being promoted without defining density requiremen­ts, urban design norms and green features for mass housing.

A dangerous trend is setting in where high floor area ratio is being pushed without first defining density requiremen­ts, mixed income use, urban design norms and green features for mass housing

How to move forward

A rapid review of emerging good practices in the country shows that progressiv­e architects are already innovating and going much beyond the limited green building policies and regulation­s to achieve sustainabi­lity and resource efficiency. Ashok B Lall, a leading architect in Delhi, says progressiv­e architectu­re retains the cultural imaginatio­n, and brings in a lot of innovative methods and technologi­es to meet the objective of equity. This traditiona­l knowledge must be extracted to add a layer of scientific understand­ing to strengthen it.

There are challenges too. Sanjay Prakash, architect with Delhi-based Studio for Habitat Futures, says one has to relook at the whole system to make a low-emission building. One has to incorporat­e measures that allow natural ventilatio­n, daylight and insulation, consider the shade, colour and orientatio­n of the building, as well as vegetation and lifestyle adaptation­s like tolerating a higher temperatur­e than what the air-condition industry provides. But lifestyle adaptation­s are frowned upon by the global cosmopolit­an community and the industry, and therefore, not popular for mainstream applicatio­n. But such buildings are sustainabl­e and cost less. “Obviously, internal white paint for daylight is cheaper than coloured interiors, suitable orientatio­n costs nothing, and reducing glass reduces capital cost,” adds Prakash.

It is clear that the accumulate­d architectu­ral wisdom and imaginatio­n has to lead the green building policies and practices, so that buildings are sustainabl­e and help improve the overall quality of life. Emerging good practices show how architectu­ral and material innovation and judicious use of modern technology can help inform the builder and consumer to upscale solutions.

This needs to be backed by policies for resource efficiency in buildings to set rigorous and transparen­t targets for resource savings, and a strong compliance strategy to ensure that buildings continue to remain efficient while in use to ensure real resource savings.

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