Green Buildings-mili Majumdar

SUSTAINABILITY

Mili Majumdar, Priyanka Kochhar and Gaurav Shorey

Green Buildings Need of the Hour

We need ‘green buildings’ if we want to use this planet a little longer.

T

he components encapsulated in the term 'sustainable development' address processes that lead to long term and/or shortterm benefits. In order to design instruments towards action for sustainable development, there is a global requirement to state sustainability principles. We could, as an

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aware group of society, direct action to increase the shelf life of Homo sapiens as a species; alternatively, increase the quality of life for individuals, at the cost of extinction. Extinction is natural and is happening. With 'development', we are merely accelerating the rate of extinction and at best, can strive to achieve 'relative sustainability'. The challenge lies in striking the balance. Since we are grappling with the fate of the human species and the world we inhabit, a safe and protected environmental media (viz. air, water and land) may help us buy time and use the earth a little longer. Voluntary building rating systems

such as LEED (Leadership in Energy and Environmental Design) as developed by the United States and BREEAM (Building Research Establishment Environmental Assessment Method) as developed by the United Kingdom have been instrumental in raising awareness and popularising green design towards protection of the environment. The Green Rating for Integrated Habitat Assessment (GRIHA), developed by TERI, India, has enumerated principles to design, operate, evaluate and maintain resource-efficient 'healthy' and 'intelligent buildings'.

WHAT IS GRIHA? The TERI GRIHA evaluates the 'greenness' of a built space against definitive standards based on accepted energy and environmental principles, both nationally and internationally. The qualitative and quantitative assessment criteria 'rates' buildings on the degree of 'greenness' in context to India's varied climate and building practices. Designed as a system that evaluates a building's compatibility with environmental priorities, TERI aims to apply the tool to mainstream the concept of green buildings in India. The TERI green rating system assures significant business and social benefits. While the rigorous efficiency and resource consumption standards of TERI-GRIHA maximise a building's operational savings, the community surrounding it benefits with an improved environment as greenhouse gas emissions and natural resource depletion are contained. The following gives an abridged overview of principles addressed

by GRIHA during the site planning, building planning and construction, and building operation and maintenance stages of a building. The TERI green building design evaluation system has enumerated principles to design, operate, evaluate and maintain resourceefficient 'healthy' and 'intelligent' buildings. GRIHA is based on accepted energy and environmental principles during the site planning, building planning and construction, and the operation and maintenance stages of a building's lifecycle. The principles such as resource conservation and efficient utilization of resources, water and waste management, indoor health, and operation and maintenance of the building underpin the green rating system and are being taken up in the following discussion. The green rating developed by TERI enumerates thirty-two criteria for evaluation during the site planning, construction and development, and operation and maintenance stages of any building so as to arrive at environmentally sensitive and sustainable development.

SITE PLANNING Usual construction practices at the site planning and development stage often entail activities that are detrimental to the site and resources (including people working on site). Disturbance of soil within the drip line of trees, for instance, in forms of cut and fill in the root zones causes harm to the existing vegetation, particularly mature trees. The damage is aggravated with carving, nailing,

fires or heat emitting construction activity. The placement of a building on site with respect to the natural functions of a plot of land (hydrologic, geologic and microclimatic) is another important criterion. Inconsiderate placement of the building with respect to the site features may result in an increased energy demand during the lifetime of the building. An increase in the hard paving on site could cause heat island effect, increase imperviousness of land and lower the localized aquifer recharge potential. Workers on the construction site also suffer due to the large volumes of suspended articulate matters that are released during construction, leading to air pollution. Furthermore, unhygienic site sanitation facilities cause damage to the environment and the health of construction workers. Combating the above-mentioned shortcomings towards resource conservation and efficient utilization of resources in site planning practices, GRIHA administers mitigation measures for the above-mentioned damages. The rating system lays down criteria that 'preserve and protect vegetation and soil from degradation during construction' and encourages conservation of topsoil till after completion of construction activity. The conservation of topsoil provides fertility to support vegetative growth. GRIHA administers soil stabilization in areas where the topsoil is vulnerable to erosion. The system also encourages design to include existing site factors so as to take advantage of the site features. By propagating reduced hard paving on site and/or providing shaded hard paved surfaces by

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encouraging a combination of soft and hard landscape, GRIHA lessens the heat island effect and the imperviousness of the site. Efficient outdoor lighting and use of renewable energy for lighting reduces the use of fossil based energy.

WATER AND WASTE MANAGEMENT Water and waste management are integral components of civic and infrastructure services in sustainable development. However, a rapid increase in construction activities without appropriate planning of civic facilities such as water supply, sanitation and waste management leads to the exploitation of natural resources. Significant savings can be achieved if responsive measures focusing on the water and waste management in buildings are incorporated into the building design at planning stage. This makes the water and waste management an integral part of sustainable building design. With large demands of water and a limited supply to meet the needs, developments that boast of large green expanses use large volumes of water for maintenance, increase the load on municipal water supply and result in depletion of ground water resources. Inefficient water use during construction for curing and building purposes further increases the load on water demand. Rainwater is a potential source of water but gets wasted when storage/recharge facilities are not provided. GRIHA therefore, addresses the issue of efficient water use by reducing demand of water with efficient fixtures and supplementing

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the supply by recycle and reuse of water (including rainwater). Reduction in landscape water requirement can be achieved by practicing 'xeriscape' that uses native/indigenous species in landscaping of the site. The native plant communities require less maintenance and water as compared to exotic species and slow down the depletion of natural resources. The water used for landscape purposes is supplemented by the treated wastewater generated by buildings. Efficient water use during construction can be achieved by using best practices in terms of using materials such as pre-mixed concrete, by using recycled treated water and by controlling water wastage during curing. GRIHA administers rainwater harvesting. When sufficient storage for rainwater is unavailable, provision is made for ground water recharge that improves the ground water level. Wastes such as asbestos products, lead, wood dust, product packaging among many others cause pollution on site. Non-segregated waste makes it difficult to recover resources and acts as burden on the landfills. In terms of waste management therefore, GRIHA administers maximum resource recovery and safe disposal of wastes to reduce the burden on landfill. Segregation of waste before processing or disposal contributes to the efficient handling and recovery of the same. In order to maximize recovery from recyclable and biodegradable waste, GRIHA advocates zero waste generation on site that also contributes towards curbing pollution for the health and

well being of individuals on site. To take waste management further, utilization of flyash in building structure as construction material is proposed. Flyash is an industrial waste having the properties of cement and very low embodied energy which when used with cements that are high in embodied energy helps reducing fuel requirement (since flyash contains some percentage of unburnt carbon), is cost effective and environmentally friendly.

ENERGY MANAGEMENT Energy constitutes a significant share in all aspects of a building's environmental performance. It is used in buildings mainly for lighting, air conditioning and other equipments. GRIHA addresses energy concerns through the life cycle of the building and administers how to r e d u c e embodied energy, energy demand during operation of the building; and integrate renewable energy to supplement demand. Distinct approaches to rate a n d a d m i n i s t e r demand for energy in air-conditioned and non air-conditioned areas are taken up in response to distinct Indian requirement. Huge quantities of waste and byproducts generated from various manufacturing processes result in consumption of primary grade raw materials such as energy, labour and capital investments in manufacturing plants. In order to conserve embodied energy consumption, GRIHA suggests reduction in volume and weight, and time of construction by adopting efficient technologies.

Sustainable management of materials helps conserve natural resources and they are characterized by low embodied energies, potential for recycle and reuse, and low emissions of toxic substances in each stage of their lifecycles. The green rating system works towards optimum use in energy systems for air conditioned buildings; and tries to achieve minimum discomfort hours for non air conditioned areas and buildings. In order to provide thermal comfort using strategies that save energy and have environmental benefits, GRIHA encourages passive solar architectural systems that employ natural means of heat transfer or air flow and incur significant energy savings for air conditioned and nonair conditioned areas of buildings. Solar passive design uses the favorable effects of the sun's heat, light and air inside the building and excludes the adverse effects with the help of efficient planning and building techniques. These techniques, taken from traditional wisdom, have been successfully interpreted in modern connotations. They aim at designing building components or techniques for storing, distributing and controlling the heat energy inside the building by effective heat exchanges based on the principles of natural energy flow. Since passive systems employ natural means of heat transfer or airflow, they are independent of mechanical controls and incur significant energy savings. Thermal comfort inside a building can also be improved by integrating simple solar passive techniques such as landscaping with other site features as micro-

climate-modifiers, optimum building orientation, arrangement and shape of buildings, effective surface-to-volume ratios, proper location and size of openings, required glazing area, shading of windows and judicious selection of building materials. The use of renewable energy sources in buildings works towards reducing the use of conventional/ fossil fuel-based energy resource and therefore contributes to reduction of air pollution. The principles of the green rating system, help achieve lower maintenance costs, reduced operational energy, lower emissions of air pollution, healthier and more productive occupants, less material usage and a longer building life.

INDOOR HEALTH Building construction and its operation affects the health and well being of people in many ways. Building materials such as paints, sealants, and adhesives form important finishes for the exterior and interior surfaces and at the same time, are potential contributors to the poor indoor air quality and can have a bearing on the occupant's health. A wide variety of volatiles are released through oxidation by both solventbased and water-based paints while sealants and adhesives contain toxic chemicals that are released during construction and occupancy. Commonly used materials such as chlorofluorocarbons (CFCs) or hydro chlorofluorocarbons (HCFCs) in refrigeration and air conditioning systems, insulation, and halons in fire suppression systems and extinguishers are

ozone depleting. Volatile organic compounds (VOCs), especially formaldehyde, urea formaldehyde, urethanes, and other chemical substances contained within the building materials can be injurious to health and can also be odorous. GRIHA therefore, aims to select materials with low to zero quantities of such chemicals so as to minimize the source of emission. (In selecting low VOC materials, a practical thumb rule is to choose waterbased products with low odour.) The various criteria suggest minimizing the release of ozonedepleting materials commonly used in buildings. To further initiative towards health and well being, GRIHA administers to provide the occupants of the building with the quality of water as prescribed by local codes and standards. It proposes appropriate noise controls for providing acceptable of outdoor and indoor noise levels to enhance comfort; and health strategies such as prohibiting smoking in the indoor areas to ensure zero exposure of the non-smoking occupants to passive smoking. Successful implementation of the GRIHA administered concepts have led to environment-sensitive and cost efficient buildings. Recent examples being the IIT, Kanpur and the Doon School, have been taken up for discussion. Case Study 1 : Earth System & Environment Science Engineering Building, Indian Institute of Technology (Kanpur) research facility Earth System & Environment

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Science Engineering Building is a research facility located in the Indian Institute of Technology Campus, Kanpur. The facility, as the name suggests would house Laboratories and other facilities for various disciplines of the environment sciences, like Atmospheric, Oceanographic, Earth Sciences etc. The facility is nestled into the existing landscape. In siting the building, the natural course was left undisturbed. The architecture of the building has been designed around the existing vegetation, so as to not disturb the natural surroundings and fully grown trees. The building is a Ground + 1 structure comprising of modules strung informally along a semi-open spine. The facility houses wet labs which are non- air conditioned spaces on Ground floor and dry labs that are air-conditioned spaces on the first floor. Building design and envelope has been optimized through selection of appropriate wall and roof construction and through adoption of solar passive measures after studying the sun path analysis to provide shading devices for windows and roof, which would reduce energy demand to condition the spaces. All the criteria and commitment as described in TERI GRIHA to optimize the system design and to achieve thermal comfort in non air conditioned spaces would be followed to reduce the annual energy consumption less than the benchmark established for composite climate by TERI. Water conservation measures would be adopted in the building through selection of efficient fixtures and rainwater harvesting. Utilization 40 ARCHITECTURE - Time Space & People November 2006

of renewable form of energy through building integrated Photovoltaic panels would be incorporated, energy generated from which shall be used in the building. With minimum disruption of existing site features, the building design considers timing of construction (to avoid soil erosion during monsoons), preservation of existing vegetation, spill prevention and control of construction activity and preservation of topsoil to 'preserve and protect landscape during construction'. Efficient energy management has been taken up for air-conditioned and non air-conditioned areas of the building. The recommendations aim to: ● Optimize building design to reduce conventional energy demand (by daylight integration, efficient artificial lighting); and ● Optimize energy performance of buildings within specified comfort limits (by optimization of building envelope and building systems) The implementation of the abovementioned guidance results in optimization of building systems. ● Efficient lighting (by using efficient lamps and fixtures, daylight sensors and lighting simulation) results in a 55% decrease of lighting loads; ● Efficient envelope and efficient lighting (through day light integration by appropriate design of external shades and efficient glazing) together reduce the building cooling load by 17.5% for air conditioned spaces and reduce the discomfort hours by 74% for non air conditioned areas.

The building, which is partly air conditioned (54%) and partly non air conditioned (46%) consumes 40% less energy. Energy efficiency in the airconditioned areas has been achieved by incorporating: ● Use of passive strategies such as integration of earth air tunnel with the HVAC systems to reduce the requirement for cooling the air. ● Efficient shading and high performance glass for windows to allow minimum solar radiation into the building but permit the light to pass through freely, thus reducing the need for air conditioning and artificial lighting. ● Efficient lighting design: light power densities (W/m2) recommended by the ECBC have been followed, simultaneously providing adequate lighting levels as recommended by the National Building Code of India 2005. ● Efficient air-conditioning system: efficient chiller and efficient air handling units, efficient pumps and motors. Water efficiency measures incorporating reduction of water requirement, recycling techniques and efficient landscaping (using xeriscape and appropriate irrigation techniques) contribute to 'greening' of the campus. Use of low flow plumbing fixtures, native species for landscaping, treatment of waste water and rain water harvesting have reduced potable water consumption by 51% and resulted in a 44% reduction for water demand for landscaping. ●

Case Study 2: The Doon School, Dehradun, Uttatanchal

The Doon School has taken the initiative to start a long-term process towards self- sufficiency in energy, water and organic fertilizer by opting for sustainable sources of energy and recycling waste. This would serve the dual purpose of having amongst India's first 'Green' school campuses and showcasing the importance of sustainability to its students by making the responsible use of scarce resources a part of their everyday life. As a part of its drive to replace many of its old buildings (which were declared unfit for habitation) it has taken the decision to design them as per an 'architectural vision statement' that incorporates standards that shall see the Art School complex (comprising the Art School and the Art Master's house)

and six teachers houses (adjoining the main playfield) built as TERI GRIHA rated habitats. Consequently, the school has ensured that the entire building process from demolition, through construction to occupancy be done as per GRIHA guidelines to achieve negligible environmental impact and a minimal ecological footprint in the long run. For instance, by changing the building envelope materials alone, the requirement for artificial space conditioning systems (cooling or heating) has been reduced to a negligible minimum. This translates into a drastic reduction in electricity consumption that may have been required for air conditioning or heating under ordinary conditions. The buildings shall also incorporate solar thermal

systems to fulfill the hot water requirements and water and waste management processes for reduced environmental impact. The school proposes to install solar thermal systems on all existing campus buildings as well as tap alternative/renewable sources of energy such as biomethanation and biomass gasification at a campus level wherever possible. ■

Mili Majumdar is Fellow & Area Convener, Green Building Rating Cell, TERI, New Delhi. Priyanka Kochhar and Gaurav Shorey are Research Associates, TERI, New Delhi. Photographs: Courtesy the Authors.

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