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.