Green buildings: it’s common sense

Green buildings: itÔÇÖs common sense

India is in a frenetic race to construct buildings. But if anyone thinks cities are built to the brim, be warned. More than 70 per cent of the buildings that will stand in India in 2030 are yet to be built. This raises green concerns. Makers and users of buildings must cut use of energy, water and materials and transform their lifestyle. Else, cities will splurge precious resources and drown in their own waste.

Scale of change

The real estate boom is driven by the scale and speed of urban growth. Although there is no official database on the building construction sector, the collage of data from the real estate industry, consultancy firms and experts reflects the boom. Close to 1.95 billion square metre of the area constructed in 2005 is a mere 20 per cent of the about 9.66 billion square metre to be built by 2030.

Big cities are major destinations for the real estate industry. The hot spots are Bengaluru, National Capital Region (NCR) of Delhi, Mumbai, Chennai, Hyderabad, Kolkata and Pune. Residential units dominate construction work. This is because the Planning Commission estimates a deficit of 26 million residential units. Given the range, from low-cost housing to high-income housing, residences are expected to have a broad bandwidth of energy and resource use.

Commercial buildings—hospitality, offices and retail—show high growth rate and are expected to guzzle more resources. McKinsey estimates that from the built-up area of one billion square metre in 2009, commercial space will grow to four billion square metre in 2030—a four-fold increase.

Bureau of Energy Efficiency (BEE) estimates that to keep pace with the demand, construction of offices will have to increase by nearly 1.8 million square metre a year in New Delhi, Mumbai and Bengaluru by 2030.

The share of organised retail, valued at US $30 billion in 2010 as per the estimates of Ernst & Young, will also gain prominence. Delhi NCR will hog 20 per cent of the future demand and Mumbai about 16 per cent. In 15 largest cities of India, shopping malls are expected to cover 7.33 million square metre area. Malls can maul cities.

Green worries

This boom can be a bane. Where and how buildings are built and used decide their damaging impacts. People’s lifestyle, their aspired comfort level, the building’s architecture, location and material influence the use of energy, water, land, biodiversity, air, waste and even vehicular traffic. These are responsible for 40 per cent of energy use, 30 per cent of raw material use, 20 per cent of water use and 20 per cent of land use in the country. At the same time, it is responsible for 40 per cent of carbon emissions, 30 per cent of solid waste and 20 per cent of water effluent.

Globally, building construction and occupation have raised energy and climate concerns. The World Energy Outlook 2009 of Paris-based International Energy Agency states that by 2030, cities will be consuming 73 per cent of the world’s energy and CO2 emissions will escalate because of increased floor space in buildings—especially in non-OECD (Organisation of Economic Cooperation and Development) countries due to lifestyle changes.

In India, buildings consume one-third of the country’s total electricity. The National Habitat Standard Mission states that building energy consumption has increased from 14 per cent in 1970 to 33 per cent in 2004-05. This is because lifestyle is rapidly changing the electric appliance market. BEE says lighting and air-conditioning use 80 per cent of the energy in commercial buildings, while fans and refrigerators guzzle maximum energy in residential buildings.

A study by Pune-based think-tank Prayas Energy shows that given the income levels in India, the major initial spurt will be in basic appliances like fans and television sets because more households will move up the income ladder. Though smaller in volume compared to fans and television sets, the air-conditioning market is already galloping at 25 per cent per year.

Add to this the water woes. All stages of construction, starting from laying the foundation to laying the roof require intensive use of water. Water demand is generally 10 to 20 per cent of the total volume of brick and concrete used in a building. But with modification in techniques, water use can be minimised. Developers will also come under pressure to capture and reuse grey water from bathroom taps, showers and baths, washing machines and kitchen facilities; black water from toilets; and storm water from the roof run-offs, impervious surfaces and drainage systems.

There is a need to reduce per capita water use in buildings without compromising on essential hygienic standards. As opposed to Central Public Health and Environmental Engineering Organisation’s prescription of 135 litres per capita per day (lpcd), other governments, like the UK, target 80 to 100 lpcd in residential buildings.

Policy push

Buildings can be constructed in a way that the threshold level of water and energy requirements are low and waste is minimised, while the comfort level is improved. The Integrated Energy Policy 2006 wants changes in the national building code to facilitate energy-efficient buildings, compulsory energy audits and solar water heaters among other energy-saving approaches.

To set the minimum energy performance standards for new commercial buildings with connected load of 100 kW and above, as well as for retrofitting of existing buildings, Energy Conservation Building Code (ECBC) has been set in place. This is voluntary but can boost the green building movement once it is mandated. Rajasthan and Odisha have notified ECBC. Kerala and Uttarakhand will do so soon.

Voluntary star labelling programme for day-use office buildings, BPOs and shopping complexes is also in place. So far, 123 buildings have been awarded energy star rating label. ECBC is the minimum standard, equivalent to one star. But with incentives, builders can target higher ranks to maximise energy savings.

According to BEE, energy used by conventional buildings is 180-200 kwh per sq m per year or higher. With ECBC it can be cut down to 140-110 kwh per sq m per year. Today, there are buidlings that consume half the energy permitted by the code. For example, Bayer Eco Commercial Building in Noida consumes around 75 kwh/sq m/ year. The building of the Ministry of Environment and Forests being constructed in Delhi is targeting less than 50 units per sq m per year.

Policies on water efficiency and conservation and waste management need to converge with energy policies to push for green buildings. Besides, proper monitoring is required for the voluntary green rating schemes.

The risks

Green building policies have created enormous opportunities for innovation in energy-efficient technology. Market is abuzz with green building products for lighting, insulation and glazing. Manufacturers claim that wall insulation products or insulated roof tiles go beyond the ECBC requirements.

While technology is an opportunity, its inappropriate selection and application can make things go awry. Climatic conditions—warm and humid, and hot and dry—govern the choice of material and design. But often, the construction industry and the wannabe clientele push for mindless application of material and architecture from the West without considering Indian climate. For instance, craze for glass in hot and dry regions—the Gurgaon syndrome—leads to unnecessary heating up and increased use of energy-intensive air-conditioning.

Unfortunately, policies cannot deliver if performance monitoring remains weak. In many cities government incentives are linked with green rating, but only Noida has mandated performance monitoring of green buildings.

Getting creative

Green building is common sense that blends traditional wisdom with modern science. Listen more carefully to the architect before habitually picking up concrete blocks and vitrified tiles, plastering surfaces with cement and painting them.

Wise architectural design lets in good glare-free daylight and reduces energy requirement for lighting. Overheating can be prevented through exposed glasses and surfaces which can reduce energy requirement for cooling purpose. Changing the orientation of buildings and using a wide variety of shading can cut heat and glare. A range of innovative cooling, insulation and ventilation techniques save energy.

Building gurus try to minimise damage to environment through locally obtained stone and responsibly harvested woods. They select material with low-embedded energy. Stabilised earth blocks, straw-bale, stone, sandstone chips and fly ash have much lower energy intensity (less than 0.5 giga joules per tonne) than glass, aluminium, stainless steel, copper, zinc, cement and readymix concrete (more than 5 giga joules per tonne).

Green building is not a fixed prescription. Architects are constantly experimenting with design and material to find low-cost as well as creative solutions. Yet, the blueprint of green building is not clear to many.

People must understand the spectrum of innovation in architecture, construction and material to customise their own solutions. There is the legendary Auroville near Pondicherry, the hub of ingenious architects inventing creative and locally appropriate solutions. Auroville has put on the global map the tradition of raw earth architecture with the modern technique of stabilised earth that can be used from foundation to roof. And more.

Look at the Agilent Technology campus at Manesar near Delhi made by Sanjay Prakash and Associates in hot and dry climate. It reflects amazing use of daylight, shading and innovative cooling systems. There is also the example of a building without air-conditioning like the Tapasya block of Aurobindo Ashram in Delhi that blends reflective surfaces, courtyards, vegetation for cooling, integrated passive solar hot water system to keep energy use very low, 12.76 kwh/ m2/ year and yet ensure comfort.

Bengaluru-based Deepak Godhi’s residence is based on stabilised rammed earth foundation, compressed stabilised earth block walls, roofs with “hourdi”—hollow block—that reduces use of solid concrete and is a great heat insulator. Also, about 60 per cent of the annual household water need is met by rainwater harvesting.

In the hospitality sector comes Samode Safari Lodge, built by Pradeep Sachdeva and Associates near Bandhavgarh National Park in Madhya Pradesh. It uses materials available within a 20-km radius—hand-moulded bricks, wood reclaimed from old houses. The edifice of local timber makes excellent use of sunlight.

Pearl Design Academy, an educational institute in Jaipur, has minimum exposed surface area. The institute has a four-metre underbelly below two stories of classrooms, studios and offices. The underbelly forms a natural thermal sink, which is cooled by waterbodies through evaporative cooling. This is a microclimate generator. A stepwell cools the building from within.

Very creatively it has used earthen pots (matkas), about 35 cm in diameter, and placed them on the flat roof, 2.5 cm apart. Spaces in between are filled with sand and broken bricks and covered with a thin layer of concrete. This provides insulation. Traditional jaali work is also used to provide shade.

Thermal comfort can also be improved in the homes of the poor. In Delhi, Micro Home Solutions offers creative and useful techniques for low-cost houses in slums to make living comfortable. It designs night shelters with easily workable material such as canvas, chicken mesh, bamboo and ropes—all eco-friendly and inexpensive. They have a double layer wall made of canvas cloth stretched over a bamboo frame. The air trapped in the envelope formed by the canvas insulates the interior.

But beware. For, experiments do go wrong at times. Widely reported is the unhealthy indoor air created as a result of mold formation in the tunnels and towers used to channelise cool air into buildings as a cooling method.

The rich collage of evidence is from the information shared by some of the leading architects with the Delhi-based non-profit Centre for Science and Environment. To know more about the creative journey and to find your own solutions, keep track of this section in the coming issues.