eco-housing guidelines for the tropical regions of asia

8/6/2019 Eco-Housing Guidelines for the Tropical Regions of Asia

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DRAFT

Eco-housing Guidelines for the TropicalRegions of Asia

Eco-Housing

September 2005United Nation Environment ProgrammeBangkok, Thailand


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Table of Contents

Executive Summary 11 Introduction 3

1.1 Global and regional trends1.2 Tsunami reconstruction

1.3 The concept of eco-housing1.4 About the project1.5 About the guidelines

2 Guidelines for Eco-housing 72.1 Pre-design guidelines2.2 Sustainable site planning

2.2.1 Site infrastructure2.2.2 Pollution considerations in site planning2.2.3 Site layout2.2.4 Landscaping2.2.5 Soil stabilization2.2.6 Restrict run-off on site

2.3 Materials and product selection2.4 Energy performance

2.4.1 Energy management2.4.2 Renewable energy

2.5 Water management2.5.1 Plumbing Fixtures

2.5.2 Drinking Water2.5.3 Treatment of waste water and reuse2.5.4 Rainwater harvesting

2.6 Waste management2.7 Indoor environmental quality

2.8 Construction administration2.9 Building commissioning

2.10 Operation and maintenance3 Application of design guidelines in the tsunami reconstruction work at

Kalutara, Sri Lanka47

3.1 Introduction3.2 About the site3.3 Analysis of the site and its microclimate3.4 Orientation and layout3.5 Soil stabilization3.6 Run-off coefficient3.7 Landscape design to reduce heat island effect3.8 Solar protection, design, and analysis3.9 Natural daylight

References

Annexures1 Glossary 632 List of local plant species recommended for the site at Kalutara, Sri Lanka 663 List of Members of the Regional Expert Group on Eco-housing 68


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Executive Summary

The activities of the construction sector are a major source of environmentaldegradation, its impacts being felt over time and space. Its geographical spread andrapid growth rate impacts the present global ecosystem. Moreover, the long lives of thestructures being built extend the impacts over several generations. This makes the

construction sector a hot spot requiring careful analysis and benign intervention. Thedynamics of current socio-cultural and economic systems ensure that the sector willcontinue to grow at a rapid rate. The development pathways of most Asian countriesare symptomatic of these trends.

The evolving concept of eco-housing is a flexible, bottoms-up approach that couldreverse the trends in the construction sector. The concept has caught the attention ofdecision makers in Asia, but a lack of real examples has prevented its adoption on alarger scale. To meet this need, UNEP and UN-HABITAT joined hands in 2004, topromote and demonstrate eco-housing as a key preventive measure in the Asia-Pacificregion. They facilitated the establishment of a regional expert group on eco-housing,which recommended that the concept be taken forward through a composite projectaddressing four key areas: knowledge building, educational initiatives, networking anddemonstration projects. The demonstration project will be implemented in Indonesia,Maldives, Sri Lanka, Thailand, China and Bhutan. Generic Design Guidelines wereprepared for Indonesia, Sri Lanka and Maldives and were discussed with national levelstakeholders in the National Inception Workshops held in the three countries in May,2005. This publication is a compilation of these guidelines, for wider dissemination.The Asian tsunami of December, 2004, added a new dimension to the project. Themassive reconstruction work provides an opportunity for integrating eco-housingprinciples. The projects in Indonesia and Sri Lanka are combined with the tsunamireconstruction efforts.

Eco-housing integrates several mature disciplines and design objectives that need tobe applied during the entire lifecycle of a housing project: design, construction,

maintenance and end of life activities. It also tries to merge traditional and modernday architectural practices. Many of its concepts have been used by humans forcenturies to ensure comfort conditions in their habitats. The drivers of environmentaland social externalities in the construction sector are dynamic in nature. Hence theguidelines cannot be rigid, but needs to blend itself in to the bio-climatic features andsocio-cultural aspects of the site. Site selection, material selection, energy performance,water management and waste management, are key areas of the concept. Integratingand implementing so many objectives and disciplines requires an effective inter-disciplinary team with good project management skills. Integrated design and projectmanagement softwares could help in this process. In general, an objective of theintegrated design process is to create minimum disturbance to the existing site andminimise the requirements of natural resources, energy and water with the help of its

bio-climatic features. A more challenging eco-housing target would be to enhance theexisting site features and even be net producers of energy, water etc, within thetraditional framework of economic-efficiency.

The guidelines presented in this publication serves to outline the broad frameworkfor eco-design in the tropical areas of Asia and build up capacity in the region. It alsochallenges practitioners to take up more ambitious targets.


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Chapter 1: Introduction

1.1 Global and Regional Trends

The design, construction, and maintenance of houses have a major impact on ourenvironment and on the stock of natural resources. Huge amounts of natural

resources, and energy are consumed in a buildings life cycle, polluting air,water, and land. The rapid growth of the global economy, and the rising trendsin population, urbanization and rural migration is contributing to the expansionof the built environment, threatening natural habitats and wildlife. Built up landincreased from 0.23 billion global ha in 1961 to 0.44 billion global ha in 2001;an increase of 91.3%. In terms of CO2 emission, experts equate one middle classhouse to two vehicles. In 1990, the residential, commercial, and institutionalbuilding sector consumed 31% of the global energy and emitted 1900 megatonnes of carbon. By 2050, its share is expected to rise to 38% and 3800 megatonnes, respectively (IPCC 1996).

These negative trends are most apparent in Asia, in comparison to the rest of the

globe. Asia has the fastest growing economies, the fastest growing middle classand the most populous countries. Furthermore, the regions economic growth ismainly localized to urban areas. For example, Bangkok alone contributes to 38percent of Thailands GDP; Jakarta, with only 5 percent of total population,contributes to 7 percent of Indonesias GDP. In 1995 the urban population inAsia was 3.5 billion (33 percent), and is predicted to reach 5 billion (53 percent)by 2025. These factors are expected to sustain the boom in the housing andconstruction sector for several decades.

1.2 Tsunami Reconstruction Work

The recent Asian Tsunami has further fuelled the demand for housing andinfrastructure in the coastal areas of Asia. Indonesia, Sri Lanka , India andMaldives, were the most affected countries with huge loss of lives, housing, andinfrastructure. The tsunami also resulted in severe environmental impacts, whichwill affect the region for many years to come. Severe damage has been inflictedupon ecosystems such as mangroves, coral reefs, forests, coastal wetlands,vegetation, sand dunes, rock formations, animal and plant biodiversity, andgroundwater. The spread of wastes and industrial chemicals, and the destructionof sewage collection and treatment infrastructure threaten the environment evenfurther. A major impact has been the salt water infiltration into fresh water andthe deposition of a salt layer over arable land (Pearce, F., 2005). Sea, sand, andearth have polluted numerous wells and aquifers. The vast devastation of

housing and infrastructure in the coastal regions has also taken a toll on peopleslivelihood. For example, in Maldives, the homes are also hubs of cottageindustries. Cottage industries bring in a substantial part of the income of mosthouseholds. With the limited mobility of women in Maldives, working fromhome is often the only source of income for them. The island women processfish for sale and storage, weave palm leaves into roofing sheets to be sold toresorts, and produce handicrafts for sale to tourists. All these industries havebeen devastated by loss of homes in the tsunami. The Maldivian homes also play


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an integral role in the water-supply chain. Roofs of the island homes aredesigned to funnel rainwater down into the communal water tanks. Supplies ofstored water were completely destroyed on 69 islands and the rain waterharvesting infrastructure damaged on many others. The groundwater has beencontaminated by salt water and human waste. Rehabilitation of the tsunami-affected regions poses an immense challenge. On one hand, there is an urgent

need for rehabilitating the displaced people in the shortest possible time while onthe other, there are the challenges of managing the available resources (land,water, energy, and costs) in the most effective manner and reverse the negativeenvironmental impacts caused during the tsunami.

1.3 The Concept of Eco-housing

The externalities from the housing and construction sector necessitate aparadigm shift in the design, construction and operation of buildings, asembodied in the concept of eco-housing. An eco-house integrates economicefficiency, resource conservation, waste minimization, renewable energy, easeof operation and maintenance, and access to community facilities. It thus enablesa healthy and cost-effective lifestyle. To achieve these objectives, an integrateddesign needs to be carried out, involving a variety of disciplines. Rather thanstudying the individual building component, system, or function in isolation, amultidisciplinary approach studies the interrelated impacts of design, systems,and materials. In Asia, eco-housing is yet to be mainstreamed into current plansand policies. Buildings have a long life, and their impacts will also be feltthroughout their lifetime. It is important that the principles of eco-design beintegrated into housing programmes being implemented now, to ensuresustainability in the long term.

1.4 About the project

The concept of eco-housing has found wide acceptance from the politicalleadership in the Asia-Pacific, but they cite the need to see working models totake policy decisions. To meet this need, UNEP and UN-HABITAT joinedhands in 2004, to promote and demonstrate eco-housing as a key preventivemeasure in the Asia-Pacific region. They facilitated the establishment of aregional expert group on eco-housing, which recommended that the concept betaken forward through a composite project addressing four key areas: knowledgebuilding, educational initiatives, networking and demonstration projects. Thedemonstration project will be implemented in Indonesia, Maldives, Sri Lanka,Thailand, China and Bhutan. Generic Design Guidelines were prepared forIndonesia, Sri Lanka and Maldives and these were discussed with national level

stakeholders in the National Inception Workshops held in the three countries inMay, 2005. The members of the regional expert group has been listed inAnnexure 3.In Indonesia the project will try to incorporate eco-housing guidelines in thecurrent tsunami reconstruction work. Apart from that, a model eco-village willalso be constructed. Proposed sites are the tsunami affected areas of Malahayati,Municipality of Banda Aceh and Calang, District of Aceh Jaya. In Sri Lanka thesite for the eco village has been prepared in Lagoswatta, in Kalutara district,


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near Colombo. The project is a part of the tsunami reconstruction project in SriLanka . It is proposed to have 57 residences and associated community facilitiessuch as a park and community centre. The plots had been allotted, and streetslaid out. The details of the project and the application of the design guidelines tothis project has been elaborated in Chapter 3. In Maldives a multipurposeGovernment Building would be built in the island of Hanimaadhoo, for which

the Government has allotted the resources. The Thai Cabinet recently approved aproject for an eco-city, as a joint venture between the Natural Resources andEnvironment Ministry, Thailand and UNEP.

1.5 About the guidelines

This report is a compilation of the eco-housing guidelines prepared for theproject in Indonesia, Maldives and Sri Lanka. A major portion of theseguidelines are generic, while some are specific to the tropical regions in Asia. Ithas been structured along the following heads.

Pre-design guidelines Site selection and site planning Material and product selection Energy performance Water management Waste management Indoor environmental quality Construction administration Building commissioning Operation and maintenance


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Chapter 2: Guidelines for Eco-housing

2.1 Pre-design guidelines

Pre-design discussions and goal setting are beneficial to the project over itsentire life cycle. It sets out definitive goals, charters project directions, and

provides opportunities for cost optimization to achieve the desired goals ininnovative ways. The generic guidelines for the pre-design stage include:

o Select an effective, interdisciplinary design team. The team could include theowner, architects, engineers, and subject consultants.

o Finalise appropriate procedures for contracting and contractor selection.Appropriate guidelines, specifications and procedures should be laid withinthe contract document to meet eco-design objectives.

o Develop design goals, which include the following. A vision statement that clearly sets out goals, objectives, and

processes. It should be based on careful site analysis, resourceavailability, available best practices and technologies, and cost-effectiveness. The project must also identify if the design goalsintend to achieve improvements over the conventional standards, e.g.,better envelope standards than minimum energy codes, better waterefficiency than the national codes.

The goals needs to be prioritized based on the need, projectconstraints, and relative importance of the criteria.e.g., water qualityand conservation may be a priority in the tsunami-affected regions.

o Laws, codes, and standards: Prepare a list of applicable codes, standards,laws relevant to the project, e.g.,

o building bye-laws of municipality,o rules/bye-laws related to water and waste management,

o financial incentives of eco-measures, e.g., subsidies for renewable energysystems, energy-efficient equipment,o energy codes/standards,o relevant building codes,o regulations related to measures like rainwater harvesting, solar water

heating, etc,o environmental clearances required, if any,o Applicable international best practices as identified in project goal, ando disaster mitigation measureso Identify the damage reversals that need to be addressed prior to

implementation of the eco-housing project, e.g., salt contamination,groundwater contamination, etc in tsunami affected areas. List out the

actions that are required to address these issues.

2.2 Sustainable site planning

The purpose of sustainable site planning is to integrate design and constructionstrategies by modifying both, the site and building to achieve greater humancomfort and operational efficiency. It ensures minimum site disruption;maximum usage of microclimate features; minimum requirement for intra/inter-


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site transportation; appropriate erosion and sedimentation control plans; andappropriate landscaping .The guidelines for achieving this are as follows.

2.2.1 Site infrastructure

o Confirm that the selected site does not fall within the disaster-control zone as

specified by the local authorityo Ensure that basic amenities such as bank, child care, post office, park,

library, convenience grocery, primary school, clinic and community hall arenear to or within the site premises.

2.2.2 Pollution considerations in site planning

o To mitigate light pollution, design exterior lighting such that all exteriorluminaires with more than 1000 initial lamp lumens are shielded and allluminaires with more than 3500 initial lamp lumens meet full cut off2IESNA3 classification. Any luminaire within a distance of 2.5 times itsmounting height from property boundary should have shielding such that nolight from the luminaire crosses the boundary.

o Plan pedestrian access ways and bicycle tracks within site premises.Discourage use of fossil fuel-based vehicles on site.

o Make a spill prevention and control plan that clearly states measures to stopthe source of the spill, contain the spill, dispose the contaminated material,and provide training of personnel . Some of the hazardous wastes to becautious about are pesticides, paints, cleaners, and petroleum products.

o The run-off from construction areas and material storage sites should becollected or diverted so that pollutants do not mix with storm water runofffrom undisturbed areas. Temporary drainage channels, perimeter dike/swale,etc. should be constructed to carry the polluted water directly to municipal

drains. The plan should indicate how the above is accomplished on site wellin advance of the commencement of construction activity.o Site should be properly planned to mitigate the heat island effect by

reducing the total paved area allowed on site. The paved areas should bemade pervious or open grid. Shading should be provided for the pavedsurfaces.

2.2.3 Site layout

o The site layout should allow for wind protection and solar access in winterand at the same time, adequate sun protection and ventilation in summer.Having a mix of building types could help achieve this. Row buildings can

be used as wind breakers. High-rise can increase ventilation in a dense

2A full cut off luminaire has zero candela intensity at an angle of 90 degrees above the vertical axis (nadir) and at allangles greater than 90 degrees from nadir. Additionally, the candela per 1000 lamp lumens does not numericallyexceed 100 (10%) at an angle of 80 degrees above nadir. This applies to all lateral angles around the luminaire.

3IESNA is the Illuminating Engineering Society of North America.


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Figure 1b: Enhancing ventilation effectiveness through landscaping


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2.2.5 Soil stabilization

o The most effective way to prevent soil erosion, sedimentation, and tostabilize soil is through the provision of vegetative cover by effectiveplanting practices. The foliage and roots of plants provide dust control and a

reduction in erosion potential by increasing infiltration, trapping sediments,stabilizing soil, and dissipating the energy of hard rain. Temporary seedingcan be used in areas disturbed after rough grading to provide soil protectionuntil the final cover is established. Permanent seeding/planting is used inbuffer areas, vegetated swales, and steep slopes. The vegetative cover alsoincreases the percolation of rainwater thereby increasing the groundwaterrecharge.

o Use of organic mulches has to be done to enhance soil stabilization. Organicmulches include shredded bark, wood chips, straw, composted leaves, etc.Inorganic mulches such as pea gravel, crushed granite, or pebbles can beused in unplanted areas. Stone mulches should not be used adjacent to thebuilding as they can easily get heated and cause glare. Mulching is good forstabilizing soil temperature also.

o Use organic compost and mychorrizal biofertilizer for remediation ofalkaline soil, as is the case with soil affected by sea water intrusion.

o Sedimentation basins, and contour trenching, also helps top reduce soilerosion.

2.2.6 Restrict run-off on site

Pervious surfaces allow rainwater to seep through them while impervious orhard surfaces prevent it. A site contains hard or impervious surfaces (roads,impervious pavements, parking, etc.) and soft and pervious surfaces

(vegetative cover, pavements, parking, walkways which are pervious). A siteplanned for a higher proportion of impervious surface results in lessgroundwater recharge and higher run-off. Conventional drainage methodsused on site usually involve transporting water as fast as possible to adrainage point, either by storm water drainage or a sewer. Sustainabledrainage systems work to slow down the accumulation and flow of waterinto these drainage points and increases on-site infiltrations. This results in amore stable ecosystem as the water level and the water flow speed in thewatercourse is more stable, and hence, less erosion will take place.

o Pervious surfaces needs to be encouraged on site in the form of pavementsand parking, which allow rainwater to seep through them. Table 1 gives the

typical values for the run-off coefficients for different types of surfaces.Pervious surfaces such as gravel or other open-textured material are onlysuitable for pedestrian or low-volume, light-weight traffic, such as walkwaysand personal driveways, but they are very easy to implement andinexpensive compared to the other methods. A combination of differenttypes of pervious surfaces such as large or small paving blocks should beused. Large blocks have large holes that are filled with soil, and allow grassto grow in them. The surface is only suitable for foot traffic or occasional


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cars but has an aesthetic benefit due to the mostly grassy surface. Smallblocks are impervious blocks that fit together in such a way so as to leavesmall openings in the joints between the blocks, allowing water to flowthrough. These blocks can take more and heavier traffic than large elementblocks.

o Well planned roadways, parkings, or walkways, with compact circulation

patterns, could minimize pavement costs, centralize run-off, and improveefficiency of movement. This would help to reduce the ratio of impermeablesurfaces to the gross site area.

Table 1: Run-off coefficient for various surfaces

Surface type Run-off

coefficient

Roofs conventional 0.70.95Concrete/ kotapaving

0.95

Gravel 0.75Brick paving 0.85Vegetation1%3% 0.23%10% 0.25> 10% 0.3Turf slopes0%1% 0.251%3% 0.353%10% 0.4> 10% 0.45

o Restrict the net run-off from a site to a maximum of 60 %. In case the sitehydrogeology does not allow the run-off factor to be 0.6, measures are to betaken to allow the collection of run-off into soak pits or collection pits so thatthe net run-off from the site is not more than 60 %.

2

Calculations for run-off coefficient on site

Gross site area: A m2 Ground coverage: p % Built-up area on site (Ab): (p / 100) x A m

2 Total open area on site (AO ): (A - Ab ) m

2 Open area on site planned for perviousness

(Ap): A1 x C1 + A2 x C2 + .Where, A1, A2 Area of various surfaces such aspavements/roads/vegetation, etc. planned for different run-offcoefficients C1, C2, etc.

Average run-off coefficient = Ap/ AO


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2.3 Materials and product selection

Using eco-friendly materials contributes towards creating an eco-habitat. Theyhelp conserve natural resources and are characterized by low-embodied energies.They are convenient for recycling and reuse, and have low-emissions. Wastesand by-products generated from various manufacturing processes could form

secondary resources for production of building materials. This would allowsavings in consumption of primary grade raw materials, energy, labour, andcapital investments in plants. Selection of appropriate materials is driven bylocal/regional availability and cost effectiveness.The points to be noted formaterial and product selection are:

o Use materials with low-embodied energy content for all structural work infill systems

o Use locally available materials and technologies, employing local work forceo Use industrial waste-based bricks / blocks for non-structural or infill wall

systemo Reuse/recycle construction debriso Minimise use of wood for interior works and use any of the following in

place of wood. Composite wood products such as hardboards, blockboards, lumber-

core plywood, veneered panels, particle boards, medium/low-densityfibreboards made from recycled wood scrap from sawmill dusts orfurniture industry and bonded with glue or resin under heat andpressure.

Materials/products made from rapidly renewable small-diameter treesand fast-growing, low-utilized species harvested within a ten-yearcycle or shorter, such as bamboo, rubber, eucrasia, eucalyptus,poplar, jute/cotton stalks, etc. The products include engineered

products, bamboo ply boards, rubber, jute stalk boards, etc. Products made from wastes. These could be wood waste, agricultural

wastes, and natural fibres, such as sisal, coir, and glass fibre ininorganic combination with gypsum, cement, and other binders, suchas fibrous gypsum plaster boards, etc.

Salvaged timber and reused wood products such as antique furniture.o Use water-based acrylics for paintso Use acrylics, silicones, and siliconized acrylic sealants for interior useo Use adhesives with no/low-VOC emissions for indoor use. It could be

acrylics or phenolic resins such as phenol formaldehydeso Use water-based urethane finishes on wooden floorso Use particleboard made with phenol-formaldehyde resin rather than urea

formaldehyde, to control indoor VOC emissionso In corrosive atmospheres, metallic surfaces, and foundation reinforcements

should be treated with suitable anti-corrosive treatments, such as epoxy,polyurethane coatings, etc.

o Minimise the use of metallic surfaces and metallic pipes, fitting, and fixtureso Use products and materials with reduced packaging and/or encourage

manufacturers to reuse or recycle their original packaging materials


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2.4 Energy Performance

The primary function of a building envelope is to protect its occupants fromsun, rain, and to provide thermal and visual comfort for work and leisure. Inorder to achieve comfort conditions, it is almost always essential to provide

energy-consuming space conditioning and lighting devices. An eco-buildingshould have an optimum energy performance and yet provide the desirablethermal and visual comfort. The energy usage of the built environment can beimproved by better a) energy management and by b) use of renewable energysources

2.4.1 Energy management

Fundamental strategies that could be adopted to optimize energy performancecan be broadly classified as follows:

Reduction in energy demand Improving energy efficiency

Reduction in energy demand entails adoption of design measures to reducespace conditioning, lighting, and service water-heating loads. The first step toreduce the energy demand is to design for the macro and microclimate of the siteby adoption of suitable bio-climatic design principles. Bio-climatic design variesfrom one climatic zone to the other. A building designed for a hot climate wouldhave measures to reduce the solar gain such as, smaller window sizes; shadedwalls; minimum exposure to the west and east; external wall and roof insulation;or use of design elements like solar chimneys, wind towers, etc., to maximizeventilation. The humidity levels of a climatic zone govern the use of water-based

measures for cooling of buildings. While measures like water bodies, fountains,and roof gardens are conducive for a hot-dry climate, these should be used withcaution in a humid climatic zone.Site microclimate is an important aspect thatmakes building designs in the same climatic zone distinct from one another.Each building site would have distinct topography, vegetation, wind-flowpattern, solar and daylight access. The design should be able to address these siteconditions and requirements.

Maximizing the energy efficiency of the building system offers furtheropportunity for energy savings. Use of efficient lighting, air-conditioning, andservice water heating systems can reduce the energy use in a building by 30%40%.


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The following are the guidelines for reducing energy demand, in terms ofstrategies for natural ventilation, wall/roof construction and day-lighting :

2.4.1.1.1 Ventilation

o A building need not necessarily be oriented perpendicular to the prevailingoutdoor wind. It may be oriented at any convenient angle between 0 30degrees without losing any beneficial aspect of the breeze. If the prevailingwind is from east or west, the building can be oriented at 35 degrees to theincident wind so as to diminish the solar heat sacrificing slightly thereduction in air motion indoors.

o Large openings, doors, and windows are of advantage in a warm-wet climateprovided they are effectively protected from penetration of solar radiation,driving rain, and intrusion of insects.

o Inlet openings in buildings should be well-distributed and should be locatedon the wind-ward side at a low level, and outlet openings should be locatedon the leeward side. Inlet and outlet openings at a high level would onlyclear the air at that level without producing air movement at the level ofoccupancy.

o Maximum air movement at a particular plane is achieved by keeping the sillheight of the opening at 85% of the critical height (such as head level). Thefollowing levels are recommended according to the type of occupancy.o For sitting on chair = 0.75 mo For sitting on bed = 0.60 mo For sitting on floor = 0.40 m

o Inlet openings should not be obstructed by adjoining buildings, trees,signboards or other obstructions, or by partitions in the path of air flow.

o In rooms of normal size having identical windows on opposite walls, the

average indoor air speed increases rapidly by increasing the width ofwindow by up to two-thirds of the wall width. Beyond that the increase inindoor air speed is in much smaller proportion than the increase in windowwidth. The air motion in the working zone is maximum when the windowheight is 1.1 m. A further increase in window height promotes air motion at ahigher level of the window but does not contribute additional benefits asregards air motion in the occupancy zones in buildings.

o Greatest flow per unit area of openings is obtained by using the inlet andoutlet openings of nearly equal areas at the same level.

o For a total area of openings (inlet and outlet) of 20% 30% of floor area, theaverage indoor wind velocity is about 30% of the outdoor velocity. Furtherincrease in the window size increases the available velocity but not in the

same proportion. In fact, even under most favourable conditions, themaximum average indoor wind speed does not exceed 40% of the outdoorvelocity.

o Where the direction of wind is quite constant and dependable, the size of theinlet should be kept within 30%50% of the total area of openings and thebuilding should be oriented perpendicular to the incident wind. Where thedirection of the wind is quite variable, the openings may be arranged equallyon all sides, to the extent possible. Thus, no matter what the wind direction


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o The ventilation indoors can be improved by constructing buildings on earthmound, having a slant surface with a slope of 10 degrees on the upstreamside.

o Raising the building on stilts is an advantage in the warm and wet climateFigure 3 illustrates this arrangement for few houses in the ongoing tsunamireconstruction project at Kalutara, Sri Lanka(refer Chapter 3). This has two

advantages: first, it enables better ventilation by locating windows above thesurrounding zone comprising lower buildings. Second, it enables cooling ofthe floor from below, which is particularly beneficial at night.

o Provide openings in roof tiles, this would enhance stack effect and enablehot air to escape outside. One such example is the kindergarten for SriAurobindo International Institute of Educational Research in the warm andhumid climate of Pondicherry, India, which has used specially designed rooftiles for escape of hot air (Figure 2).

o Provision should be made for forced ventilation strategies by use ofceiling/wall-mounted fans, exhaust fans.

o Provide buffer spaces like staircases, lifts, store, toilets, double-wall withoutopening etc, on at least 50% of the west wall

Figure 2: Recessed windows, extended roof, ventilated roof by special designed

tiles for esca e of hot water


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o Hedges and shrubs deflect air away from the inlet openings and cause areduction in the indoor air motion. These elements should not be planted upto a distance of about 8 m from the building because the induced air motionis reduced to a minimum in that case. However, air motion in the leewardpart of the building can be enhanced by planting low hedges at a distance of2 m from the building.

o Trees with large foliage mass having trunks bare of branches up to the toplevel of the window, deflect the outdoor wind downwards and promote airmotion in the leeward portion of buildings.

2.4.1.1.2 Wall and roof construction

o Due to the climate characteristics of warm--wet region, with small diurnaltemperature range, the heat capacity of buildings should be as low aspossible. This will avoid accumulation of heat in the day time and itssubsequent release in the night time.

o External wall with high thermal resistance is recommended to minimize theheat flow from external surfaces warmed by the sun.

o The main heat flow from roof to the space below is due to radiation. Theroof should be protected against excessive heat gain by appropriateinsulation to give an U-value (thermal conductivity value) as specified by thelocal energy conservation building code. Bonded mineral wool could be usedfor underdeck roof insulation. Resin-bonded mineral wool comprisingrockwool and glasswool is available in the form of slabs and rolls of density2448 kg/m3 and thickness 2575 mm. These materials are available with orwithout lamination of aluminium foil. High-density 96 and 144 kg/m3 rigid

Figure 3: Raising alternate row of houses on stilts


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slabs and boards are also available. The typical thermal conductivity is about0.029 W/mk at 10 C mean temperature. Aluminium foil lamination isrecommended for this application. Cost of mineral wool insulation (materialonly, for 50 mm thick and 48 kg/m3) is approximately 3 USD/ m2(excluding taxes), and the cost of application with accessories is extra.

o Instead of roof insulation, a roof garden on the exposed roof area or a shaded

roof, would help to reduce heat ingress.o Light-weight tiles with low heat capacity are preferred for the roofs, but it

might cause heat stress during daytime.o The roof could be painted with light colour, instead of a dark colour. Light

colour helps reflect heat and solar radiation outwards. This would aid inreducing the heat island effect also.

o Thermal barrier paints: These paints are energy-efficient, energy-saving,flexible coatings, made from a water-based pure acrylic resin system filledwith vacuumed sodium borosilicate ceramic micro spheres of less than 100microns in size. Each micro sphere acts as a sealed cell and the entire masticacts as a thermally efficient blanket covering the entire structure. Thesecoatings are non-toxic, friendly to the environment, and form a seamlessmembrane that bridges hairline cracks. They have high reflectance and highemittance as well as a very low conductivity value. Roof coats greatly reducethermal shock and heat penetration by keeping roof surfaces much cooler inhot summer weather. They offer UV (ultraviolet) protection and low VOC's.They display excellent dirt pick-up resistance and retain their flexibility afterageing. Roof Coats reduce noise transmission and have an effective userange from -40375 C (SPM Thermo-Shield Inc). The approximate cost ofapplication of thermal barrier paint is about USD 24/m2.

o Wall insulation should be considered in the event of a building being air-conditioned. Some commonly used wall insulation types like mineral woolslabs, expanded/extruded polystyrene, aerated concrete blocks, etc could be

used for this purpose.

2.4.1.1.3 Day Lighting

o The rooms should have good access to day light. Daylight analysis for site-specific conditions should be carried out. The fenestration should beoptimized for day-lighting and thermal comfort. Day-lighting goals shouldbe based on the intended usage of the space and the design illuminationlevels recommended by IES (Illuminating Engineering Society, NorthAmerica). Appropriate light control strategies could be applied after ananalysis for integrating day-lighting and artificial lighting.

o Efficient glazing systems that maximize day-lighting and providing suncontrol should be adopted.

2.4.1.2 Energy Efficiency

The main energy consuming equipments in buildings are the HVAC(Heating,Ventilation and Air-conditioning) and lighting systems. The efficiencies ofthese systems could vary depending on the technology used and the way they are


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operated and maintained. Following are few guidelines for getting the best out ofthem and thereby minimising energy consumption

2.4.1.2.1 Lighting System

o Use renewable energy-based lighting system for external lighting.o Lighting power density could be restricted to 7.5 W/m2o Use fluorescent/compact fluorescent lamps operating on low-loss ballast for

general lighting of brightly lit spaces and common/circulation areas, such aspassages, staircases, lifts, corridors, lobbies, and other common areas.

o Use HID (high-intensity discharge) lamps with minimum circuit efficacy of80 lm/W for outdoor lighting,e.g., high-pressure sodium vapour lamps.

o Apply control devices, such as timers or photocells, to turn lights on and off.o Provide fixed/pre-wired luminaires with sockets that will only accept lamps

with high efficacy.

2.4.1.2.2 HVAC System

o For space conditioned buildings, apply insulation of high thermal resistance(R-value) throughout the building

o Minimize use of glass in buildings. Glass should not cover more than 50% ofthe wall area.

o Wherever glass is used, consider the use of double-glazed low-e windowswith effective interior shading devices.

o Provide outside shading (louvers/fins, etc.) to windowso Orient the longer axis of the building eastwest, so that the shorter walls face

north-south.o Avoid excessive illumination levels inside, which will add to the cooling

load inside the building. Use those types of lighting that efficiently convert

electrical energy into light , instead of heat, e.g., CFLs instead ofincandescent bulbs.o Use high efficiency window air conditioners. The window air conditioners

have lower operating efficiencies, compared to split or central airconditioners. Window air-conditioning systems are now available with someenergy-saving features, such as sleep mode and filter-clean reminder. Thesleep mode feature helps to save electric energy by increasing the settemperature, when the occupants are sleeping. While sleeping, the humanmetabolic rate drops. During this time it is not essential to cool the room upto the normal set point. For example, if the window air conditioner is usuallyset at 22 0C and switched to sleep mode, it raises the set temperature by 10C (230C) after a few hours. The increment continues every hour for the next

four hours or so. By early morning, the set temperature is a comfortable260C, which not only improves the comfort level but also helps save energy.The single-biggest reason for inefficiency in window air conditioners is adirty filter. A clogged filter results in increased power consumption and poorcooling. The filter-clean reminder feature reminds the user, when the filter isto be cleaned.

o Though split air-conditioners are more expensive than the window type, theyare preferred for their low noise levels as the noisier components are kept


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outside the conditioned space. A comparison between window and split airconditioners is given in Table 3.

o Water cooled AC systems should be preferred over air cooled systems.Water-cooled units are of higher capacity and more energy-efficientcompared to air-cooled units. Air-cooled units are more suitable for placeswhere water is scarce or of hard quality or where there is no space for

installing a cooling tower. In air cooled units, the condenser (heat rejectionunit) is cooled by the air blown by a fan. In water cooled units, water ispumped through the condenser. This heated water is then sent into a coolingtower outside the air-conditioned room where heat is dissipated into theatmosphere.

o In all HVAC systems the, scaling or soiling of the heat transfer surfaces(condenser, cooling tower and evaporator) would reduce the systemefficiency. Hence it is important to have proper maintenance practices.

Table 3 : Characteristics of non-central air-conditioners available in India

Available sizesSystem type Advantages Disadvantages Recommended

applications Cooling

capacity

(TR)

Input

power

(kW)

Window air

conditioners

1) Inexpensive

2)Easy-to-install

3)Independent

control

4)Low service and

maintenance cost

1)Limited capacity

2) Noisier

3)View blocking

4)No constant fresh

air circulation

1) Homes

2)Small offices

3)Executive cabins

4) Small shops

1

1.25

1.5

1.75

2

1.40

1.50

1.80

2.00

2.30

Split units 1) Quieter

2)Available up to 5TR

3)Do not block

view

4)Multiple units

possible

5)Suit theinterior

better

6)Aesthetically

better

1)Costlier than

window units2)Outside space

requiredfor outdoor

unit

3)Some piping and

cabling required

4)Do not provide for

fresh air intake

1)Senior executive

cabins2) Small and mid-

sized showrooms

3)Up-market homes

4)Small clinics

5)ATMs

1

1.52

3

4

1.60

1.902.50

3.80

5.00

2.4.2 Renewable energy

Use of renewable forms of energy, based on solar, wind, and biomass energy helps

in reducing demand for polluting, conventional fossil fuel based energy. Fossil fuels

supply 80 percent of the worlds primary energy at present, but resource depletion

and long term environmental impacts might curb their use in future. Hence policy

makers are increasingly turning to renewable energy as a more sustainable option.

At present renewable energy such as hydropower, solar energy, wind energy,

biomass, and geothermal energy meets 13.5 percent of the global energy


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demand.(Muneer,T.,et.al, 2004) The most likely application of renewable energy in

the residential sector would be based on solar, wind or biomass energy. A short

description of few solar energy applications for residential users in the tropical

areas of Asia , is given in the sections below.

2.4.2.1 Solar PV based applications

2.4.2.1.1 Solar photovoltaic technology

The solar PV (photovoltaic) technology is primarily semiconductor based and isused to convert solar radiation into electricity. A PV system comprisesphotovoltaic modules, which collect and convert solar energy into electricalenergy and the balance of systems ( BOS) designed to store, and deliver thegenerated electricity. Balance of systems include the support structure; wiring;batteries; power electronics and controls.The material commonly used for solar cell production is silicon eithercrystalline (single and poly) or amorphous silicon. Out of it, crystalline Si cells(with efficiencies of 15%17 %) are the most popular, though more expensive.The other technology used for PV modules is the thin-film technology. Thin filmsolar modules are cheaper because less material is used and it has a relativelyeasier manufacturing process. Inspite of this, it still has a smaller market, mainlydue to its relatively lower efficiency (10%12%).Generation is possible only when the sun is shining, so a battery is needed tostore electricity and use it at night or during periods of insufficient sunshine. Inplaces where sales to the grid is possible and attractive, the user could avoid theuse of batteries, by using the grid as the storage medium. The user could sellelectricity to the grid when demand is low, and take electricity from the grid,when demand is high. An inverter is used to convert the DC current into ACcurrent, which is required by all common loads.

Solar modules are specified in terms of peak wattage, which is measured understandard test conditions(STC). The STC is specified as 1000 W/m2 solarradiation, Air-Mass ratio of 1.5(corresponding to zenith angle of 48.2o)2 andtemperature of 25oC. Under normal conditions, the PV module may not producethe same output as specified due to the variations from the STC. The amount ofsunlight and hence the output from the PV module, varies according to the angleof the module relative to the position of the sun in the sky. The maximum outputis obtained when the sun rays fall perpendicular to the surface of the module.During the day, the output increases as the sun rises in the sky and reaches peakat mid day and again decreases gradually as the sun goes down and falls to zeroat night. The sun angle also changes during the year, with sun being higher in

the sky during summer and lower in winter. Unlike solar thermal panels, solarelectric panels are very sensistive to shading. Hence the tilt angle is important.

2Air Mass(AM) is a concept used to specify the effect of the clearness of the sky on sunlight. Itis equal to the relative length of the direct beam of sunlight through the atmosphere. It can befound out from the relation Air Mass = 1/Cos A, where A is the zenith angle. At sea level, on aclear day in summer, solar radiation at Zenith corresponds to Air Mass 1(AM1).(Zahedi A,1998.p.18)


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The suggested tilt angle for PV modules is at an angle equal to the latitude of thelocation. In winter the optimum value is latitude+15 degrees and in summer it islatitude15 degrees (Kyocera, 2004). To achieve optimum output, there aretracking systems available, which have computer controlled motors that canchange the slope of the solar panel by five degrees every 15 minutes for aroundseven mid-day hours. This could increase the output by around 30 percent,

compared to the modules with fixed slopes.(Zahedi,A, p.43) The compassdirection or azimuth of the module also is important. i.e., the angle with respectto the north-south-east-west direction. Ideally the module should be facingsouth. Any change in angle from the south direction would decrease the amountof solar radiation and PV output.

Photovoltaics can be integrated virtually on every kind of structure, from busshelters to high-rise buildings. They can also be used as landscaping elements.At present, PV based power is more costly compared to that of grid electricity.But in places with no access to the electricity grid, PV system is an attractiveoption. One of the main advantages of the PV systems is that power can begenerated at the building site thus, reducing dependence on grid electricity.

2.4.2.1.2 Building integrated PV systems (BIPV)

PV arrays are normally mounted on special-support structures. However, theycan also be mounted on buildings or even be made an integral part of the

building envelope. There are several building elements that can readilyaccommodate PV, such as curtain walls, atria, and roofs. In addition, newproducts are being developed with PV as an integral component, such as activeshading elements, building glazing, or roof tiles. By definition, each BIPVproduct is either integrated into a building element or completely replaces anexisting building elements. The building value of the BIPV element can be

Figure 4: Stand alone photovoltaic system with AC loads


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assessed by comparing it with typical building elements without the PVcomponent. From an architectural, technical, and financial point of view, theadvantages of a BIPV system is

It does not require extra land for installation, It can replace conventional building materials such as window

glazing, roof tiles, etc., in addition to being a power generationoption.

It provides an aesthetic appearance in an innovative way.

Once put in the building context, PV can be regarded as multifunctional buildingelements that provide both shelter and power. For instance, the BIPV as roofserves the following functions: provides structural stability and durability;provides protection against chemical and mechanical damage; provides fire

prevention; protection against rain, sun, wind, and moisture; allows heatabsorption and heat storage; controls diffusion of light, etc. In addition, as anelectricity generator, it will meet a part of the electrical load of the building.

Standard modules with frames are widely used in existing buildings forretrofitting purposes. However, these frames impede an easy and elegantintegration and hence, for integration applications, laminates are preferred.Laminates can be mounted like glass panes, using conventional glazingtechniques. These are double-glass modules, which are semi-transparent.Another technique for PV integration is using PV tiles or shingles that can beinstalled very quickly and easily. They have the look and function of asphalt andcomposition shingles. Wire connections are made below the roof decking.

With growing interest in PV facades, manufacturers are now offeringcustomized sizes and options to modify the modules appearance.The BIPVproducts can be transparent, semi-transparent, or opaque, depending on themodule technology. For example, the colour of mono-crystalline cell-basedmodules varies from uniform black to a dark grey with a uniform surfacestructure. In contrast, the structure of the module using poly- or multi-crystallinecells show irregular grey-to-blue coloured crystals. In both types, the currentgathering screen-printed silver grid lines are visible. The balance between the

Figure 5: Roof integrated photovoltaic system-

Biosolar house,Pathumthani, Thailand


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Figure 6: Solar home

system in India

amount and quality of glass and type of cells used in the module is part of thedesign process, and will decide the aesthetics and functionality of the module.For semi-transparent modules, space between the cells is enlarged to let lightpass through. This lowers the ratio between the cell area to the total module area,or in other words, its fill factor ( FF )3 is low. For modules using thin-filmtechnology, transparency depends on the extent to which light can penetrate the

cells. As cells absorb a part of the spectrum, the colour of the transmitted lightchanges. These modules are uniformly dark brown in colour. For BI PVsystems, the trend is gradually shifting towards polycrystalline Si solar modules.In India, cost of a PV system is approximately, USD 7750 per kW (includingbalance of system costs). The BIPV systems would be costing more: anindicative range is between USD 10000 120004 per kW.

2.4.2.1.3 Solar Home System (SHS)

It consists of a single PV module of 1875 W capacity; a deep discharge-typelead acid battery; charge controller; 1, 2 or 3 CFLs (compact fluorescent lamps);and a DC power point for another appliance such as radio, tape recorder. Themodule generates energy that is stored in the battery and can be used at any timeof the day. The cost is approximately USD 5.5 6.5 /W. Usually, the modulelife is in excess of 20 years, but the battery is normally replaced within 45years. In India, the battery costs around USD 46.5 for a smaller system andUSD 116 186 for larger systems.

2.4.2.1.4 Small-capacity village power plants or mini-grids

A mini-grid is refers to small power plants that supply three-phase AC electricitythrough low-tension distribution networks to households for domestic power,commercial (for example, shops, cycle repair shops, and flour mills) activities,

3 Ratio between cell area to total module area4 Because of high demand in European markets, prices of solar PV systems in Indian markets arenot stable and are on the rise.


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and community requirements such as drinking water supply and street lighting.State-of-the-art batteries and inverters are used to ensure long life and reliablefield performance. An appropriately designed mini-grid can easily supply powerfor 810 h daily. Though there is no limit on the capacity of the mini-grid, PV-based mini-grids are typically of 25100 kW. Installation, operation andmaintenance of these mini-grids are normally contracted on a turnkey basis to

the PV supplier. At the local level, the village community is expected to play acritical role in facilitating payment collection, monitoring of theft, complaintredress, etc. Due to the high initial investments involved, PV systems arepromoted by many Governments through subsidies on initial investment.

2.4.2.1.5 Solar street lighting system

Street lighting is another application, which could utilizes solar photovoltaictechnology. It is a stand-alone system that operates automatically by sensing thedaylight at dawn and dusk. A typical system has the following configuration:

74 W solar PV module 12 V, 75 Ah tubular plate battery with battery box Charge controller cum inverter 11-watt CFL lamp with fixtures 4-m-mild steel lamp post above ground level.

2.4.2.1.6 Solar water pumps

Pumping of water is an application, which does not require battery storage. Inthis system, PV modules are directly coupled to the motor-pump unit and wateris pumped as long as the sun shines. There are several system designs based onvarious types of motor and pump sets. The most commonly used ones in India

are 900 or 1800 W DC surface and AC submersible motor-pump sets. Thesepumps are suitable for both drinking and irrigational requirement.

2.4.2.2 Solar cookers

Several design of solar cookers are available in the market. In India, solar box-type cookers is the most common. This is being promoted by the MNES(Ministry of Non-conventional Energy Sources), Government of India, since theearly 1980s. These are available in different sizes, suitable for cooking for afamily or a group of 68 persons.The approximate cost in India is USD 48-70depending on models and size. Each cooker can save 34 LPG (liquefiedpetroleum gas) cylinders of 14.4 kg each, per year. Solar dish cookers are used

for community cooking. It can save 5 to 10 LPG cylinders per year. A dishcooker of 4 sq m collector area can serve for 10-15 people per day in India. Theapproximate cost is USD 95-120/m2 of the collector area of the cooker. Theimportant guidelines to note for installing solar cookers are:

o Solar cookers need south-facing gallery or open space free from shadow.The place should be free from shadow for at least four hours during the dayaround noon time.


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o Kitchens having south-facing wall can be provided with a retractable /slidingplatform on the outside to keep the solar box cooker. This will reduce thework of going to the terrace or open-ground and solar cooking can bemonitored from the kitchen.

o Kitchen design and layout should be finalized in consultation with thecooker supplier in case of a concentrating cooker (scheffeler cooker). This

can reduce the construction cost and can help in using the cooker moreefficiently.

2.4.2.3 Solar stills

The use of direct solar energy for desalting saline water has been investigatedand used for some time. These devices are popularly known as solar stills.During World War II, considerable work went into making small solar stills foruse on life rafts. This work continued after war with a variety of devices beingmade and tested. These devices generally imitate a part of the naturalhydrological cycle in that the saline water is heated by the sun's rays so thatproduction of water vapour increases. The water vapour is then condensed on acool surface, and the condensate is collected as water(the product). An exampleof this type of process is the greenhouse solar still, in which the saline water isheated in a basin on the floor and the water vapour condenses on the slopingglass roof that covers the basin. In a solar still plant, the only moving part is thepump, used to pump saline water from the well. The solar still can de-salt salinewater having a wide range of salinity, including sea water. In addition, it alsoremoves toxic ions and bacteriological contamination. Thus, solar stills are idealto provide safe drinking water to isolated communities of small villages, islands,lighthouses, and salt works. They can be constructed in modular form too andprovide a viable option of providing potable water for a single house or a groupof families. Some preconditions for setting up solar stills of relatively larger

sizes are as follows:

o Uninterrupted supply of saline water preferably over 10 000 ppm and sunnyweather throughout the year.

o It is a sensitive equipment and hence requires proper operation andmaintenance.

o The quality of the glass sealing plays a very crucial role as far asperformance of still is concerned as vapour-leakage through the jointsappreciably reduce the output.

The capital cost of a commercial solar still of 1 m2 area is about USD 120. Theaverage yield of a 1 m2 single slope, single basin, solar still is about 2 litres per

day.


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2.5 Water management

Water supply, water quality, and its management is an important componentwhile designing an eco-friendly and sustainable habitat. Considering theincreasing demand and limited availability of water, it is important that it beused and managed efficiently.In efficiently managing its water resources, mostcountries in Asia lag behind the developed countries and a lot could be done toimprove the situation. As an example, we could compare the consumption ofwater in bathrooms and toilets. The combined consumption of toilets, showers,and faucets is around 2/3rd of indoor water use. In India, conventional toilets use13.5 litres water per flush. In 1988, the state of Massachusetts of USA amendedits plumbing code to require the use of low flush toilets that will use only 6.2litres/flush. Later, Energy Policy Act of 1992 (Table 3) established standardsthat require new toilets to have a flow rate of 6.2 litres/flush, urinals with a flowrate of 3.8 litres/flush, and showerheads and lavatory and kitchen faucets with a

flow rate of 9.5 litres/flush.Table 4: EPACT fixture ratings

Fixture Flowrequirements

Water closets(litres/flush)

6.2

Urinals(litres/flush)

3.8

Showerheads(litres/minute)

9.7

Faucets(litres/minute)

9.7

Replacementaerators(litres/minute)

9.7

The guidelines for an effective water management system are

Figure 7: Solar still


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o Prepare a water balance for the site. The demand could be estimated basedon standard consumption norms for specific categories of housing

o Fix norms for water quality from various sources as per the specified localstandards for different applications

o Use efficient fixtures for uniform distribution of water at the desired pressureand avoid wastage and losses

o Ensure regular monitoring of both consumption patterns and qualityo Adopt planting of native species and trees with minimal water requiremento Use mulches and compost for improving moisture retention in soilo Promote low-cost decentralized waste water treatment systemo Develop norms based on existing standards for reuse of treated water for

non-potable applicationso Encourage rainwater harvesting and storage/recharge for capturing good

quality water. This is particularly important for coastal areas wheregroundwater is saline and intrusion of sea water has occurred

o When water is sprayed on concrete structures for curing, free flow of watershould not be allowed.

o Concrete structures should be covered with thick clothe/gunny bags andwater should be sprayed on them, which would avoid water rebound and willensure sustained and complete curing

o Concrete building blocks should be cured in shadeo Ponds should be made using cement and sand mortar to avoid water flowing

away from the flat surface while curing

2.5.1 Plumbing FixturesPlumbing fixtures recommended to reduce water consumption are as follows:

2.5.1.1 Low-flow flush toilets

To minimize water consumption for flushing, low-flush toilets with a flow rateof 6 litres/flush or ultra-low-flush toilets with flow of 3.8 litres/flush could beused.

Figure 8: Low flow fixtures


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2.5.1.2 Composting toilets

Composting toilets do not require any water. This is based on the biologicalprocess of conversion of solids present in human waste into enriched manure.The system consists of two underground pits. The first pit gets filled with wastein less than two years and during this time, the waste is acted upon by bacteria

resulting in digested sludge, which is odourless and safe to be used as a soilfertilizer. After filling up of the first pit, the usage of second pit starts.

2.5.1.3 Low-Flow Urinals

Low-flow urinals consume water at the flowrate of 3.8 litres/flush use same formateverywher. Use of an electronic flushing systemor magic eye sensor can further reduce the flowof water to 0.4 litres per flush.

2.5.1.4 Waterless urinals

Waterless urinals use no water but a biodegradable liquid for cleaning. Thisfunctions by allowing the urine to pass though the biodegradable liquid using afunnel system called cartridge thus preventing any odour and maintains ahygienic surrounding. The advantage of using such a system is not only savingwater but also reducing the load in the sewer system. The average life of thecartridge is 7000 uses.

2.5.1.5 Water taps

The use of conventional faucets results in flow rates as high as 20 lpm (litres perminute). Low-flow faucets are available which can result in withdrawal of waterat a flow rate of 9.5 lpm at pressures of 80 psi(pound per square inch). Inaddition to this, further reduction of water consumption is possible by using:auto control valves, pressure-reducing device, aerators and pressure inhibitorsfor constant flow, and magic eye solenoid valve self-operating valves.

2.5.1.6Showerheads

Showers of different diameters at different pressures result in different flow

rates. The conventional showerheads have a range of flow rates of 1025 lpm ata pressure of 60 psi. Reduction in water consumption is possible by the use offixtures with flow rates of 9.5 lpm at 80 psi.

2.5.2 Drinking Water

People in villages suffer from water-borne diseases caused by microbiologicalcontamination. Excessive levels of fluoride,nitrates, iron, and arsenic can cause

Figure 9: Sensor-based

urinal


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severe health disorders. Water needs to be stored properly and treated, beforebeing used for drinking purpose.

2.5.2.1 Household level treatmentSome means of disinfecting water at household level are enumerated below:-

2.5.2.1.1 Boiling

Boiling is a very effective method of purification and very simple to carry out.Boiling water for 10 to 20 minutes is enough to remove all biologicalcontaminants.

2.5.2.1.2 Chemical disinfection using chlorine

Chlorination is done with stabilised bleaching powder (calcium hypo chloriteCaOCl2) , which is a mixture of chlorine and lime. Chlorination can kill all typesof bacteria and make water safe for drinking purposes. About 1 gm(approximately tea spoon) of bleaching powder is sufficient to treat 200 litres

of water. Sometimes chlorine tablets are used. They are easily availablecommercially. One tablet of 0.5 g is enough to disinfect 20 litres of water

2.5.2.1.3 Filtration

a. Charcoal water filter

Figure 10: Water filter

A simple charcoal filter can be made in a drum or an earthen pot. The filter is madeof gravel, sand and charcoal, all of which are easily available


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b. Sand filters

Figure11: Sand filter

Sand filters have commonly available sand as filter media. They are easy andcheap to construct. These filters can be employed for treatment of water toeffectively remove turbidity (suspended particles like silt and clay), colour, andmicro-organisms.

2.5.2.1.4Ceramic filters

These filters are manufactured commercially on a wide scale. Most waterpurifiers available in the market are of this type.

2.5.2.2 Rural Applications

More sophisticated systems are available for various kinds of rural applications.For example, ION Exchange India Ltd5, an Indian water treatment company, hasdeveloped a suite of products for rural application. To remove suspendedimpurities , they have two systems: a) on-line dosing coagulant system and b)Lamella clarifier for surface water with high flow rate and high turbidity .On-line dosing system prevents microbial growth in treated, stored water. Othersystems have been developed to treat brackish water, fluorides, arsenic, and iron.These are also available as hand pump attachments. The particles are eitheradsorbed on a resin or onto a catalytic media.

Another option for providing quality water at low cost is to use package plants.Package plants consist of various components of the treatment process, such aschemical feeders, mixers, flocculators, sedimentation basins, and filters in acompact assembly. As these units are assembled based on standard designs, theyare cheaper as compared to those that are built on site.

5 http://www.ionindia.com/


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Figure 12: Arsenic removal kit with Hand pump

2.5.3 Treatment of waste water and reuse

Waste water has to be treated adequately so that clean water could be safelyreturned to the environment. If the treated water meets the desired criteria level,then it could be reused for various applications. Reuse depends on the qualityand the type of application.

Graywater from bathrooms, washings, can be suitably treated and reusedfor non-potable applications such as irrigation, flushing, etc. Different types oftreatment techniques can be adopted, depending on land availability, quantity,and the characteristics of waste water. Treatment plants, which are used fortreating sewage, are usually based on the biological process. The process isdependent on natural micro-organisms that utilize oxygen and organiccontaminants in waste water to generate CO2, sludge, and treated water. Thesystems could be based on either suspended growth or attached growth. Thesesystems normally require a pre-treatment step such as settlement chamber before

the aeration unit.

These conventional centralised systems to dispose waste water, face severalproblems like water stagnation, clogging, overflow with a foul smell, mosquitoinfection, and contamination of groundwater. Using the conventional method, itis difficult to meet the criteria for discharge or reuse. It is beneficial todecentralize the waste water treatment, which ensures that there is littlepossibility for groundwater contamination. There is also the advantage thatrecycled water can be used for irrigation/ flushing purposes. Two systems arebeing highlighted here, due to their advantages in terms of cost, treatmentefficiency, and operation reliability. Eco-friendly, low energy DEWATS Root zone system

2.5.3.1 Eco-friendly, low energy DEWATS

DEWATS stands for Decentralized Waste Water Treatment System, based on amodular and partly standardized technical design. Since 1960, BORDA (BremenOverseas Research and Development Association) has been initiatingdecentralized waste water system (DEWATS) in India and China. Modules of


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DEWAT can be designed as per the site requirement. The system has successfulexamples in Auroville, Pondicherry, India. The project is a cooperation betweenGerman and Indian not-for-profit organizations financially supported by the EU(European Union). The Arvind Eye Hospital in Pondicherry has a system withthree components: a) Anaerobic baffled reactor, b) Planted gravel filter, and c)Polishing pond. The effluent is collected in an open underground water tank

from where it is emptied daily for irrigation purposes.

Another example of decentralized waste water treatment in Auroville is a plant,which serves three communities that accommodate up to 200 residents. Thethree communities are equipped with individual Imhoff tanks for pre-treatment.Such a tank has been considered useful for loads above 3 m3 /day. The threeImhoff tanks connect to a single inlet box for feeding the planted filter (Figure14). From here, water is further channelised into a huge polishing tank. Theplanted filter is divided into two separate operating parts. Two fountains areinstalled for oxygenation purpose.

ks serve 200

Baffled Reactor Planted Filter Open Tank

Figure 13: DEWATS used in Arvind Eye Hospital, Pondicherry


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Table 4: Plant overview

Start of operation 1998Retaining structure Bottom: concrete, walls: bricksDesign capacity 10 m3/ dayWaste water type Domestic

Total plan area of the system 614 m

2

Pre-treatment 3 Imhoff tanks combined capacity of 84 m3Main treatment Horizontal planted filter of 400 m2, depth of 60

cmPost treatment Polishing tank of 190 m2, 171 m3Filter media Granite stones, pebbles, sandPlant species Arundo donaxMode of disposal Reuse for irrigation purposes

Imhoff tank consists of a settling compartment above the digestion chamber.Funnel-like baffle walls prevent up-flowing sludge particles from getting mixedwith the effluent and from causing turbulence. De-sludging is necessary at

regular intervals. Leaving some bottom sludge behind in the tank helps thestarting up process, i.e., decomposition of settled sludge. The sludge could beused as manure for vegetation and crops of individual houses.

Figure 15: Principle of the Imhoff tank

gas

manholeOutflow

Longitudinal section

inflow

1. Sedimentation2. Protection against up flow of sludge particles3. Fermentation of bottom sludge


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2.6.3.2 Root zone treatment system

Nowadays, there is growing interest in artificial wetlands or reed bed systems,which are based on the use of deep-rooted plants for waste water treatment. TheRoot Zone treatment system, is one such system developed in 1970 by Dr

Reinfold Kickuth of Germany.The system is suitable for treatment of wastewater from various sources containing biodegradable compounds. It is based onthe principle of attached growth biological reactors similar to the conventionaltrickling filters with combination of aerobic and anaerobic zones. Thecontaminants present in waste water are treated by seepage of pollutants throughthe root-zone of plants by a combination of plants, soil, bacteria, and hydraulicflow systems resulting in physical, chemical, and microbiological processes.Oxygen present in the zones facilitate degradation of waste water. A variety ofmicro organisms and reactions in the root zone of plants , maximise removalefficiency.

The treated water could be used for irrigation of landscaped areas or flushingpurposes. Dual plumbing has to be deployed if the latter option is adopted.Root zone system is being used in TERIs(The Energy Research

Institute) RETREAT Building at Gurgaon, India.

Fi ure 16: Root zone s stem

Figure 17: TERIs RETREAT building, an example where root zone system is

used in India


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The land area required for a Root Zone treatment plant is around 30-35 m2/m3 ofwaste water treated per day. According to Indian standards for residentialcommunities with population up to 20000, the quantity of water consumed andtherefore waste water generated (litres per head per day) = 70100 litres. InIndia, the cost of a root zone treatment plant that could treat 1000 LPD ofsewage is about USD 2380 .

2.5.4 Rainwater harvesting

Rainwater harvesting is traditionally practised in many parts of Asia, e.g., inMaldives this is the only source of drinking water in many islands. PVC tanksare predominantly used for storing rainwater. The decision whether to store orrecharge water depends on the rainfall pattern of a particular region. Maldivesbeing a high rainfall zone, rain falls throughout the year, barring a few dryperiods. In such a case, one can depend on storage tank as the period betweentwo spells of rain is short.

Rainwater drainage pipes collect rainwater from roof to storagecontainer. Appropriate precautions should be taken to prevent contamination ofstored water. Mesh filters provided at mouth of drain pipe prevent leaves anddebris from entering the system (Figure 19). Further, a first-flush device shouldbe provided in the conduit before it connects to the storage container (Figure20). If stored water is to be used for drinking, a sand filter should also beprovided . Underground masonry/RCC (reinforced cement concrete) tanks/ overground PVC tanks could be used for storage of rainwater. Each tank must havean overflow system connected to the drainage/recharge system.

Figure 18: Traditionally used rainwater harvesting system in Maldives


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Figure 19: Mesh filters at roof level

Design of storage tank

The quantity of water stored in a rainwater-harvesting system depends on thesize of the catchment area and the size of the storage tank which is designedbased on the water requirements, rainfall, and catchment availability.

For example, suppose that the system has to be designed for meeting the

drinking water requirement of a five-member family living in Kalutara district ,

Sri Lanka. The house has a roof-top area of 75 m2. The average annual rainfall

is 3000 mm. Daily drinking water need is 10 litres/person, including cooking.

Maximum amount of rainfall that can be harvested from rooftop = area of

catchment (A) x average annual rainfall (R) xRun-off co-efficient (C) = 75 x 3 x 0.95 = 213.75 m3

The tank capacity has to be designed for the dry period, that is, January to

March in Kalutara, which is about 90 days

The drinking water requirement for five persons in the dry season =90 x 5 x 10

= 4,500 litres

Figure 20: First shower flush device


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Applying safety factor of 20%, the tank size should be 5400 litres for the dry

period requirement of five persons in a family.

It should be noted that during the dry period, the stored water should be usedonly for drinking purposes. However, in the wet period, the collected watercould be used for all household purposes.

Quality of stored water

Rainwater collected from rooftops is free of mineral pollutants like fluoride andcalcium salt but is likely to be contaminated by air and surface pollutants. Allthese contaminations can be prevented largely by flushing off first 10-20minutes of rainfall.Water quality improves over time during storage in tank asimpurities settle in the tank if water is not disturbed.Even pathogenic organismsgradually die out due to storage. Additionally, biological contamination can beremoved by the above means. Specifications for drinking water should be asprescribed by the WHO (World Health Organization).

2.6 Waste management

Waste generation is associated with every human activity. Waste generated fromhousing colonies consists of a mix of biodegradable, non-biodegradable, andinert waste. Organic wastes include vegetable, food, animal, leafy, andagriculture wastes. Municipal solid waste is usually dumped in landfill sites.This leads to air and water pollution. Through efficient waste managementmethods, a significant amount of solid waste entering the landfill could bediverted and reused. Natural waste decomposing is a very slow process andtherefore, it is better to go for alternative technologies, such as bio-methanation.Among the various options available for treatment of the organic fraction of

solid waste, bio-methanation is the most desirable because it has two benefits: ityields biogas, which can replace conventional fuels and it provides digestedsludge, which can be used as an organic manure.


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The inorganic part of solid wastes, like paper, metals, and plastic should bediverted for recycling purposes. Recycling reduces the need to extract virginnatural resources. For this, the organic fraction of waste has to be separated,before it gets mixed with the other components forming a heterogeneous mixturethat become difficult to handle. A separate bin system should be arranged forstoring non-degradable waste such as metal scrap, rubber, and recyclable wastessuch as paper and plastics. These bins should be in different colours to facilitate

disposal. The local Government could be responsible for the collection of non-degradable, recyclable, and reusable waste. The guidelines are as follows:

o Provide facilities for collection of segregated waste at the household andcolony levels

o Identify facilities for recycling of non-biodegradable wastes such as plastics,glass, and paper

o Develop decentralized treatment systems at site based on composting oranaerobic digestion process for segregated organic waste

o Identify appropriate options for use of by-products from treated organicwaste, such as biogas and manure

o Develop norms for use of by-products based on local standardso Develop norms for disposal of non-degradable and inert waste in landfills

based on local standards, to ensure safe environment in the surrounding areaso Perform regular checks on plumbing systems to check for leakages,

wastages, and system degradationo Establish an efficient waste reduction, recycling, and reuse programmeo Minimize toxic wastes by recycling items such as ballasts, mercury-based

lighting products, used oil, unusable batteries, etc.

Figure 21: Schematic diagram for bio-methanation process


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o Reuse construction debris. In isolated areas that do not have indigenousmanufacturing units for building materials, like the islands in Maldives,building materials have to be imported. Optimization of building materialsbecomes a priority in these areas. In such cases, the use of constructiondebris after segregation and crushing could be considered. This is especiallytrue in the case of areas affected by natural disasters, like the tsunami

affected areas of Asia.

2.7 Indoor environmental quality

People spend 80%90% of their time indoors, at home, school, and work .Hence indoor environmental quality is an important parameter in sustainablehabitat. Poor indoor air quality causes headaches, tiredness, shortness of breath,and allergic reactions such as sinus congestion, irritation of the eyes and throat,sneezing, coughing, and wheezing. In some cases, an allergic reaction of thelungs (hypersensitivity pneumonitis) has also been reported.Indoor air quality isaffected by ventilation rates, temperature and humidity, building materials, kindof devices used indoor (mainly unflued devices), and outdoor air pollutionentering into the home. Biological contaminants also contribute to the poorindoor air quality. In coastal regions, warm, humid conditions provide anexcellent environment for breeding of dust mites, moulds, and fungi. Thecontaminants include animal dander, water-borne microbes, moulds, etc., all ofwhich can cause an allergic reaction. Some organisms can contaminate watersources and become air-borne through humidifiers. Combustion by-products dueto incomplete burning of fuels (oil, gas, kerosene, wood, coal, etc.) generategases and tiny particles like carbon monoxide and respirable suspendedparticulate matter, nitrogen dioxide, formaldehyde, ammonia, etc, which areknown to cause adverse health impacts. Radon is a naturally occurringradioactive gas given off by traces of uranium in soil and rock. Radon is not

generally a problem in the coastal regions, but some buildings in the interiorhave been found to have levels that could increase the long-term risk of lungcancer.The guidelines for maintaining indoor environmental quality are as follows:

o Use interior finishes and products with zero VOC (volatile organiccompound) or low VOC content. Limits of VOC content should be as perestablished international or national standard.

o Indoor ventilation rate should be maintained as per ASHRAE 62-2004 ornational standards

o Design for indoor thermal comfort level as per ASHRAE 55 : 2004.o Avoid use of hazardous materials.e.g, asbestoso Provide operable window for air-conditioned spaceo Keep the house clean and dust-free to reduce allergens such as house dust

mites, pollen, and animal dandero Avoid leaving any material that could degrade/rot inside houseo To prevent growth of mould, lower the humidity by venting moist areas or

by installing dehumidifiers or humidistatso Disinfect the house regularly, especially whenever mould is seen to be

growing


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o Optimize water use in construction by adopting water-efficienttechnologies.e.g., use of ready mix concrete .

o Use recycled water for constructiono Recycle and use construction debris

2.9 Building commissioning

Commissioning involves examining and approving or withholding approval ofthe building and its sub-systems to ensure that it is constructed in accordancewith the contract documents, and performing as intended. Commissioningenables integration and organization of design, construction, operation, andmaintenance of a building and its sub-systems. The guidelines for the buildingcommissioning process are:

o Select the processes and systems that are to be commissionedo Prepare a detailed commissioning plano Prepare the criteria for processes and systems to be commissionedo Include commissioning process in the contract documento Designate a commissioning agento Involve the design team in monitoring the commissioning processo Ensure commissioning in accordance with contract documento Carry out systems and equipment start-upo Prepare the commissioning report

2.10 Operation and maintenance

The O&M (operation and maintenance) costs throughout the building life cycleis considerable and could exceed the buildings initial investment. The designintent of a building and systems is not met unless it is maintained properly.

Appropriate maintenance procedures helps to keep the building and its sub-systems in order, so that they give the same output as during the initial stages.The guidelines for O&M are:

o Ensure that qualified professionals are engaged in operation andmaintenance

o Train facility staff for proper maintenance of facilitieso Prepare a detailed O&M plan with written policies and procedures for

checking and inspection, preventive maintenance, repairs, and cleaning.Material safety data sheets and information on cleaning, chemicals to beused for cleaning, frequencies of cleaning, and pest-control methods shouldbe properly documented and followed.

o Monitor the performance parameters of the buildings and compare it withestablished benchmarks.

o Monitor thermal and visual comfort parameters


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Figure 23:The site

3.0 Application of Design Guidelines in the TsunamiReconstruction Work at Kalutara, Sri Lanka

3.1 Introduction

This chapter describes the application of the Generic Design Guidelines for the

demonstration project in Sri Lanka. The proposed development is a part of thetsunami reconstruction project in Sri Lanka. The tsunami reconstruction proijectinvolved the construction of 57 residences and associated community facilitiessuch as a park and community centres. The plots had been allotted, and streetshad been laid out. The design of the houses has been finalized and constructionhas begun. It is expected to be over by December. The eco-housingdemonstration pro

eco-housing guidelines for the tropical regions of asia

Documents