building green for sustainable development

7/28/2019 Building Green for Sustainable Development

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BUILDING GREEN FOR SUSTAINABLE DEVELOPMENT

Eng. WJB Shiromal Fernando

(Vice Chairman, Green Building Council of Sri Lanka)

Introduction

Climate change and sustainable development is greatest challenge of the man today. The

increasing population growth which is predicted to be 9.5 billion by year 2050 uses earthslimited resources at a rapid space. In the process we emit greenhouse gases (GHG) to the

atmosphere which will cause climate change which will threaten the very existence of the human

race. The scientists firmly believe that to the frequentfloods, droughts, cyclones, landslides andcoastal erosions are due to the results of climate change.

One of major concern among people, scientist and environmental policy makers is global

warming, particularly due to increasing emission of CO 2. This is resulting in global climate

change. It is reported that CO2 concentration has increased from 280ppm (pre-industrialrevolution 1750) to 368ppm in 2000. It is projected to reach 540-970ppm by 2100.

The fig. 1: shown below shows how the CO2 emission has increased in Sri Lanka. It is alarming

sign, since a small island like Sri Lanka is able to release such a massive amount of CO 2 into the

atmosphere, just imagine how much the whole world must be releasing into the atmosphere.

The tropical rain forests (see fig.2) are the key absorbers that balance the carbon dioxide levels inthe atmosphere. Deforestation due to human activity had caused the imbalance of GHG levels in

our atmosphere. You may be surprise to note that Sri Lanka is 4 th in the list of primary forest loss

(see fig. 3).

Construction industry contributes to forty percent (40%) of the GHG emissions, which all of us

whom are responsible. Common argument on this matter is that the developing nations are the

main culprits and small counties like us cannot do much about the GHG matter. There is a Yes

and No to the argument. Yes when you look at the statistics (see Table 1), per capita CO2

emissions of countries like US, Australia, Japan and UK is very much higher than Sri Lanka.

No, we should not take our resources for granted. We have experience a rapid disintegration of

our natural construction material during the past few years, such as granite and sand which are

the main constituents of our main building material concrete. Now we are to looking foralternative construction materials. Had we used our material efficiently we could had sustain the

materials for our future use.

We use construction waste for landfills, which causes environmental damage as well. If we had

recycled at least 50% of it, we could have saved 50% of materials for the future. Today we use

drinking water for construction without considering the cost of production of drinking water.

Commercial rate of drinking water is Rs.30/= - 40/= per litre, which is quite comparable with


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fossil fuels. Most of us do not realise flushing our toilet, irrigating our flower beds and washing

our cars utilizes two third of our water usage.

Fig.1: CO2 emission in Sri Lanka (From Carbon dioxide information center)

Using drinkable water for these purposes is a crime. It is heartening to note that the localauthorities have made rainwater harvesting mandatory for commercial buildings in colombo, but

this regulations must extend for house units too. Rain water shall be mandatory to manage within

the ones compound, which could avoid flash floods in the city, which is a common site during a

stormy weather.

We are living in a tropical country with blessed weather condition. Why we design building to

condition the air? .This causes our biggest energy bills. We are blessed with Sun light 12hours a

day and 7 day per week, why do not utilise Sun light our during the day to produce our energy to

light our buildings in the night.

Thus it is time to change our building design and construction practices. The design and

construction practices shall be efficient. When we say efficient, our building design shall be

futuristic and flexible enough to change by our grandchildren. They should be strong and

durable. We shall not save a penny today so our grandchildren had to spend a pound to make it

their habitat. We shall plan our habitats efficiently so that the transportation is efficient. The


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buildings shall not be located in green field; they shall be confined to building zones. Mainly our

buildings shall suit our culture and our social behaviours.

Fig. 2: Tropical rainforests of the world

Our construction shall be very efficient with minimum waste and minimum impact on the

environment. We shall reuse the fertile top soil and stop erosion of the excavated material which

will block our waterways. The main philosophy is to reduce waste, use recyclable material for

construction and shall recycle waste.

Fig. 3: Worst deforestation rate of primary forest, 2000-2005 percentage forest loss


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Table 1: CO2 emission (metric ton per capita)

Green Building

Ofall things humans build, buildings last the longest, so we have to get buildings right Prof.

Richard Reed, Deakin University

Green building and sustainable construction is one of the most discussed topics of the day,

among the construction professionals. There are many forums organized to educate

constructional professionals on important aspect of green building techniques. Green Building

Council of Sri Lanka, which was established in November 2009, with the participation of all the

key professional organizations, Government organizations and business leaders related to

construction industry, is focus to popularise the concept of green building in Sri Lanka.

Sustainable construction is not a new concept to Sri Lankans. Our forefathers had been building

on these concepts 2000 years ago. Renowned Architects like Geoffrey Bawa had designed

sustainable buildings even before the term sustainable construction was coined, famous

Kandalama Hotel (see fig.4) is one of his noteworthy contributions. When we look at ancient

structures like Sigiriya ( see fig.5) built by King Kashyapa (AD 477-495), it is amazing to note

the sustainable techniques that has been used without destroying the beautiful environment. Thus

we have a heritage of sustainable built environment. We need to put that knowledge in to

practice without just following the design and construction practices of the developed nations. In

fact our cites are still green, Colombo city (see fig. 6) is one of the greenest cities in the world.

The effort is to protect it with the rapid development.

Green Building practice address the following issues; efficient construction management and

documentation, building on sustainable sites, efficient use of water, efficient designs on energy,


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efficient design of indoor environment, efficient use of material and resources, design to suite the

social and cultural setting and recognise innovation.

Fig. 4: Kandalama Hotel


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Fig. 5: Segiriya- ancient rock fortress and palace build by King Kashyapa (AD 477-495)


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Fig.6: Colombo City

Site selection and landscaping

In a sustainable building technique the site selection and landscaping plays a vital role. Construction on

any sensitive habitats like wetlands, groundwater recharge zones or old growth forests should be avoided.

In Sri Lanka we do have many brown fields, which can be effectively utilized for construction.

Brownfield are land area, which have been used for construction previously, this helps in refraining ofdeforestation. The new development shall be located in a urban setting where all amenities of the

occupants shall be in close proximity to reduce long distance travelling. The site also shall not get

inundated due to the frequent flooding etc.

Maintenance of natural terrain and drainage will help in maintaining a good site condition with good

drainage and erosive free ground. Proper planning is required in avoiding unnecessary wastage of land

area and to utilize natural green vegetation cover, which can help in avoiding soil erosion.

Proper storm water discharge is essential during the construction process. Since it is one of the main

causes of soil erosion. Avoiding the removal of vegetation cover at the site can alleviate erosion, silt traps

and storm water ponds also help this course. Storm water pond helps in collecting the rain water. They

should be placed at lower elevation, such that the water will get collected by gravity flow. Silt traps canbe attached with these ponds to remove the debris and soil particles. This water can be used for

construction. But should make sure it does not get contaminated by soluble minerals such Sulphates

available in the soil. Excavated soil from the site should be maintained properly such that it does not get

into atmosphere and produce air pollution. This can be done by covering the excavated soil by means of

polythene sheets; if part of the vegetation cover is removed they can be used for covering the excavatedsoil.


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If the excavated soil is sandy, it can be reused after grading it for concreting or masonry work. If its clay

it can be utilized for brick production. Peat soil can be transferred to a less fertile land and can be used for

agricultural purposes. Debris of the excavation can also used for paving sub base. Not only makes the sub

base stronger at the same time reduces the waste that goes to landfills.

Indoor Environment Quality

Sun shines brightly down on Sri Lanka almost throughout the year. This results in air conditioning the

building unit. Air conditioners consume a lot of energy to keep the building interior comfortable. Even

though it may make the interior cooler, the concentration level of CO2 maybe higher due to limited

circulation of air, which can cause detrimental health effects on the building occupants.

Alternative for this problem can be achieved in two steps. One is passive cooling. It includes the

orientation and massing of building volumes, controlled fenestration (Doors & Windows) and ventilation,

shading of the building and its surroundings, and thermal mass and solar reflectivity of the facades and

roofs.

Orientation of the building plays a major role in heat gain of the building. It is preferable to orient the

building such that the longest sides are facing south and north. High thermal mass in the structure helps

in absorbing the heat and reducing the heat transfer into the interior. Roof insulation helps to reduce the

heat gain to the buildings. This can be done with the help of polymeric material such as expanded

polystyrene, which have lower heat transfer factor.

Active system of cooling is provision of mechanical or natural ventilation system. In a sustainablebuilding it is recommended to avoid conventional air-conditioning system, which consumes a lot of

energy. In the case of Sri Lanka we should encourage naturally ventilated buildings. Placing of windows

should be such that it does not all the direct solar radiation into the interior, which can increase the heat.

Using the cross ventilation technique we can ventilate the whole building. Cross ventilation employs

window openings which are not directly opposite to each other, so that the wind will travel in diagonal

path and the stack effect takes the hot air into a higher elevation, they can be removed by openings at

higher elevation. This concepts have been effectively used in Idea House in Malaysia (Fig. 7)


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Fig.7: Utilization of natural ventilation

Other method of ventilating recommended in a sustainable building is evaporativecooling system. These units draw in fresh air, filter it, and add moisture to lower the dry-bulbtemperature. The air is distributed through a balanced system of ducts and fed into the spaces, which

remain under positive static pressure. Indoor air is not re-circulated, but extracted by suitably sized

exhaust fans to ensure effective moisture and heat removal.


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Fig.8: MAS Intimates Thurulie Factory

MAS intimate Factory in Thurelie is leading by example in industrial sector by being one the greenest

factory in the world


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Table.2: Comparison between various factories in their energy consumption

The table gives a good idea on how a sustainable building can reduce the energy consumption

Materials

When we decide on materials that we are to be used to construct buildings, we should be mindful of

several aspects, first and foremost is the impact of using that material to our environment. For example

use of one tone to cement will produce one ton of CO 2. Thus we shall use concrete in a very efficiently.

Steel is a material, which can be recycled effectively. Their usage in green building is highly

recommended. The scrap metal collected from various sites can be effectively used in the building.However if we dont provide a proper painting system to protect it from corrosion in our aggressive costalenvironment, the above said benefits will not be there.

Our exterior walls can be made from compressed stabilized earth blocks, which can be made from local

soil, sand and cement. The embodied energy (It is the energy, which are uses on processing and

transporting) is comparably low with the conventional blocks and when consider the total wall, the carbonfoot print will comparably low with the conventional wall construction. The figure 9 shows the use of

compressed stabilized earth blocks, which were made locally and used without plaster finish.

Fig.9: Compressed stabilized Earth blocks (Thurulie

Factory)

.

For interior partition walls can be made from gypsum

board and table top MDF (Medium density Fiber) which

are not only lighter in weight they last longer. Another

option is Ferro cement walls made of thin layer of concrete

reinforced with wire mesh will have a longer lifetime.


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Roof

Roof is considered to be the largest contributor to heat gain and indoor discomfort in the tropical regions.

This can be reduced my use of green roofs. As shown in the fig above, they can be installed in Concrete

decks. High thermal mass absorbs the heat and does not transfer into the building. As a result produces acomfortable indoor condition and at the same time reduces heat island effect which primarily takes place

in urban areas. Heat island effect is nothing but the effect which arises due to absorption of heat by the

massive concrete structures results in increment in temperature around the building.

Other option is cool roofs. Which can be achieved using light weight metal roofs made of white colour.

Such that it will have the capability to reflect around 70-80% of the solar radiation. Another option isphotovoltaic roofs, which not only able to produce renewable energy but also prevents heat gain.

Fig.10: Green roof at Thurulie factory

Lighting


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Lighting accounts for 15% of total energy consumption in India. Lighting is an area that offers many

energy efficiency opportunities in almost any building facility, existing or new. Using efficient lighting

equipment and controls is the best way to ensure lighting energy efficiency while maintaining or even

improving lighting conditions. For instance, modern fluorescent lighting, such as electronically ballasted

T-8 systems, can provide the same quantity of light as older fluorescent lighting while consuming as littleas two-thirds of the energy. Similarly, compact fluorescent sources are three to four times more efficient

than the traditional incandescent lamps they are designed to replace. LED (Light emitting diode) lampsare also very effective.

Fig.11: utilization of daylight

Windows and skylights allow daylight to reach the interiors of buildings, reducing the need for artificial

light. However, windows are the weakest point in the building envelope in terms of energy loss, and

much research has gone into developing more efficient window systems. Improved glazing techniques

offer low-emissivity glass and inert gas-filled air spaces between panes. The window sash and frame

have also been improved with added insulation and seals. Heat gain through direct solar radiation is the

easiest to prevent, by providing shading devices and using low-emissivity (low-E) glass. Low-E glass acts

as a radiation mirror, reflecting infrared (heat) rays back to the source. This prevents solar heat gain inthe summer and retains heat within the building during the rainy season.

The wood provides a better insulating value than vinyl or aluminum alone and adds strength to the frame.

These windows are particularly desirable in residential construction, as the wood can be left exposed on

the interior of the window. The fiberglass sash is more receptive to the airtight sealing required when

using argon gas-filled airspaces between panes. Because fiberglass, being composed chiefly of strands of

glass, has a thermal expansion coefficient similar to glass itself, the materials expand and contract at

approximately the same rate, this means that there is less stress to the sealants and the material of the

windows as a whole. Although there is currently no recycling process for fiberglass, there is the potential

for reuse, due to the products long lifespan.


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Use of blinds in the window openings can help in reducing the effect of excess light. Bamboo blinds are

effective as blinds. Since bamboo has the capability of growing a short period of time. Lighting controls

are another effective way in utilizing the artificial lights. When the illumination level is not sufficient

inside the building the controls will switch on the artificial light.

Water Management

Fig.12 Simple Rainwater collection system in Villages

Water management is essential in present situation, we can witness greater increase in cost of water, in

future it may escalate to unprecedented levels. Proper water management can help in reducing wastage ofwater. Rainwater harvesting is one-way, where the rainwater can be collected from the roofs and can be

stored in tanks and can be used for flushing and irrigation of landscape. 1m 2 roof area receives 1litre of

rainwater for each mm of rainfall. This water can accumulate to large quantity, which can serve for many

purposes. Most of these schemes implemented in the dry zones have failed due to the very low rain fall,thus rain water harvesting shall be in the wet zone since there are frequent showers. This is why our

forefathers build large water tanks to store water in the dry zone. Ground water recharge is also better

way to store storm water for future use.

Most of us do not know, most of the potable water delivered to our house by make a very incurring huge

expense by the National Water Supply and Drainage Board (NWSDB) flushes down our toilets. One

toilet flush will use eleven liters of water. The use of proper water fixtures in the buildings can help in

reducing the high consumption of water, such as dual flush system toilets and low-flow plumbing

fixtures. Dual flush toilets have the capability of discharging less water for flushing.


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Energy

Energy efficiency is a key component of green buildings. Renewable energy sources like solar, wind and

geothermal increasingly important. Tropical country like Sri Lanka, solar radiation is in abundance. It

gives a great opportunity to produce electricity using the photovoltaic system. Photovoltaic system works

on the principle of converting solar energy into electrical energy. Heat energy can also use for heating the

water, using solar collectors mounted in the rooftops.

Sri Lanka being an Island, the coastal regions experience higher wind speeds, which can be effectively

utilized for generating electricity. In Puttalam wind turbines have been already installed and there are

projects planned to implement wind turbine farms in chilaw, Hambanthota and Mannar.electricity. Micro

wind turbines can be used in medium to high-rise buildings to generate electricity, which have been

effectively used in foreign countries. They should be made from lightweight meterial so that they can be

mounted in the rooftops. They can supply the energy required for the building.

Fig. 13: Wind Turbines in Puttalam


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Fig.14: Micro wind turbines in US

.

Fig. 15: PhotoVoltaic system on roofs


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Why green building rating is important for Sri Lanka?

Since the export markets are very sensitive to sustainable productions, Sri Lankan entrepreneurs

are moving towards building green in their new ventures. Since Sri Lanka hadnt had a clear

framework and governing body for green rating of buildings in the past they used to seek other

ratings as LEEDs. The processing fee for to obtain a rating relatively very high and this factor

discouraged developers to build green. Thus there was an extreme necessity for such an

institution for Sri Lanka. Green building council of Sri Lanka was formed under the leadership of

Prof. Priyan Mendis ( University of Melbourne), with the patronage of all the stake holders of the

building industry.

The main purpose of green building rating set higher standards than the present building codes

and to encourage the design and construct buildings in an environmentally acceptable manner.

This will be a major step towards adopting a sustainable practice in development and to utilize

the natural resources efficiently for the betterment of the mankind.

The most of the resources that are being using today are accounting for environmental pollution.

Thus it is the time to search for new materials and reduce the impact to the environment. Hence

this concept will encourage development of environmental friendly building solutions.

Future with Green rating system

The GBCSL is the governing body of Sri Lanka responsible for developing and implementing the

green rating and maintaining such system. The governing body comprises with the experts in the

different disciplines who effectively contribute to the operation of such system. Further throughGBCSL the green accreditation certificate will be issued for building designs and constructed

according to GreenSL Rating System, then the council will monitor implementation and the

operation phases of the building to check its efficiency. Further in other countries like Australia

and Singapore government has made compulsory to obtain green rating for all the government

buildings. GBSCLwill appoint the accredited professionals whom will be the facilitators to rate

the buildings. These professional qualifications will be awarded by GBCSL after completion of

necessary training and examinations.


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GREENSL Rating System for Built Environment

The GREENSL Rating System for Built Environment is a set of performance standards used to

certify Built Environments in the form of commercial or institutional buildings and residential

buildings of all sizes, both public and private. The intent is to promote high performance,

healthy, durable and affordable environmentally sound practices for new buildings.

Prerequisites and credits in the GREENSL Rating System for Built Environment address eight

aspects;

Management (04)

Sustainable Sites (25)

Water Efficiency (14)

Energy and Atmosphere (22)

Materials and Resources (14)

Indoor Environmental Quality (13) Innovation and Design Process (04)

Social and Cultural Awareness (04)

The total of 100 points will be awarded based on the efficiency of the building . The

Certifications from the GREENSL Rating System for Built Environment will be awarded

according to the following scales;

Certified 4049 points

Silver 5059 points

Gold 6069 points

Platinum 70 points and above

GBCSL will recognize buildings that achieve one of these rating levels with a formal letter of

certification.

Conclusion

The concept of green buildings is an emerging trend in the design and construction of sustainable

building solutions for different industries. Most of the countries are already working on ratingthe efficiency of buildings to assess the environmental acceptability of their buildings which is

governed by the governing body for green rating. In the development process of Sri Lanka,

having such system is critical for the assessment of buildings. Having such intention to

incorporate greener concept for building solutions, the GBCSLwas organized and established.The proposed GREENSL rating system for built environment is very popular among the


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professionals and the developers of the building industry. Currently there are more than 100

building under review. Public and private sector professional should jointly work for the green

movement of Sri Lanka, so that our grandchildren will enjoy a sustainable future.

building green for sustainable development

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