The objective of making / calling a building green is three fold. These can be achieved with the following requirements:
1. Minimize the generation of greenhouse gases like (carbon dioxide) CO2 by using appropriate Building Planning, Construction materials etc.
2. Use of low energy intensive materials like Portland Pozolana Cement etc during construction.
3. Use minimum quantity of high energy materials like cement, steel, bricks etc in construction of Buildings.
4. Similarly use minimum amount of energy like electricity, fuel etc during operation or living.
For Making a Building Green following Information will be useful.
In 2004, the average worldwide power consumption of the human race was about 15 TW or 15×1012 W with 85% coming from burning fossil fuels like Oil, coal, natural gas etc. The energy consumption in India increased many fold, say from 4.16 to 16.8 Quadrillion Btu in the last few years, putting India next to US, Germany, Japan, and China in total energy consumption. Because of such thermal power generation and various other human activities, lots of Green House Gases (GHG) is produced. Following are some of the main components of Green House Gases, which enter into atmosphere.
- Carbon Dioxide (CO2)
- Methane (CH4)
- Nitrous Oxide (N2O)
- Fluorinated Gases, etc.
In addition to the above gases, Volatile organic compounds, asbestos, carbon monoxide, nitrogen dioxide (NO2), Sulfur Dioxide (SO2) and combustion gases also affect air quality. These are introduced in the indoor environment also by paints, glues, solvents, wood preservatives, installation of carpets or through cleaning products.
Effect of Global Warming:
Because of climate change, the air is getting warmer – summer comes sooner in most Continents including Europe and America. Sea level is rising – the Maldives Island is sinking. Mangrove forests of SUNDERBAN in India, which are the unique islands and world’s most prosperous group of 104 Rainforest Islands, are likely to be wiped out from earth’s map soon. In fact 16% of Sunderban Islands have already been submerged in the ocean. Now the threat of submerging is looming large on Sagardeep, the 4th biggest of the existing island. It is also on this Island, that the annual Mela of Gangasagar is held and visited by Millions of pilgrims.
Thus, the global warming may result in:
- Likely temperature rise between 1.80C to 40 C
- Sea level rise – most likely to be 0.28 – 0.43 m
- Artic summer sea ice disappearing in this century.
- An increase in heat waves likely
- A likely rise in tropical storm intensity.
- Erratic or Changed Weather conditions.
According to NASA satellite data, the Arctic Ocean could be nearly ice free very soon, much faster than previous predictions. Faster melting of ice there means eventual sea level rise and more immediate changes in winter weather because of less sea ice. While sea ice reflects about 80% of the sun’s heat off earth. When there is no sea ice, about 80% of the heat goes directly into the ocean which than warms up everything else. Warmer oceans ultimately lead to more ice melting.
The glaciers feeding water for the Holy River GANGA are also melting faster than it should. It means the River GANGA could become a stream in another 100 years or so. This would leave more than 60 million people hungry and thirsty who are living and surviving on the banks of this river all along its alignment / route.
Concrete: A Sustainable Construction Material:
Selecting construction Materials for high performance in Green Buildings is most difficult and challenging task for any design team. Several criteria’s are possible for this purpose and the best tool is Life Cycle Assessment (LCA). LCA provides information about the resources, availability, emissions and other impacts resulting from the life cycle of material used in buildings from extraction to disposal. The following simple guide lines/rules can be followed while selecting the material.
1. Actual material should consume least energy to Manufacture.
2. Material should involve least transportation distance – for the raw materials as well as for finished products.
3. Material used in it should not much influence the environment.
4. Product should be easy to recycle and safe to dispose.
5. Product should be durable.
Among the various Construction materials, Concrete is the most versatile material for construction and hence it is the primary construction material in the World and cement is the main component of concrete. The use of concrete is increasing every day and is expected to double in the next fifteen years. As a rough estimate, two ton of concrete is used globally per person per year.
I. Concrete – A most positive material for Sustainable Building:
Some parameters of concrete are very relevant in connection with sustainable mater. Some of them are given below.
a. Concrete has many positive qualities:
- It has high Strength and effective mass.
- It can be locally caste in shape.
- It can be used in main body or in interior and finishes – as required.
- Due to its use in interior, air quality does not get affected.
- It is easily cleanable
- It is almost impervious and resistant to insect damage
- It is fire resistance and is chemically inert for most chemicals.
- It is durable and Cost effective
- It can also be designed as pervious concrete and hence can be used as a paving material, allowing rain water to percolate through it into ground.
b. Recycling Properties of Concrete:
The recycling properties of concrete are also good. Crushed concrete waste can be effectively used as aggregate in roads, low grade concrete and in making concrete blocks similar to brunt clay bricks. Such concrete with waste aggregate can be easily used upto M25 grade. Recycling of concrete waste along with other construction waste will conserve resources and also save fresh construction material resources and land fill space? Further, use of manufactured sand and mining waste in place of river sand is also environment friendly and can be used in concrete. Several other byproducts like foundry sand broken glass, fly ash etc can be equally beneficial in concrete and will make it sustainable.
Typically concrete mix contains 12-15% cement and 75-80 % aggregates. Globally sand, gravel or crushed rock is used at the rate of 10- 11 billion tones every year and is effecting the environment and ecology. The cement can be partially replaced by cementitious materials or industrial by-products like fly ash; blast furnace slag, silica fumes etc in concrete mix. They can also be mixed in the cement itself, to save on the clinker. The Cement consumption in concrete can be optimized / minimized through any one of the following approaches:
1. Consume less Clinker in Cement making-up by adding Pozzolana- a waste material like fly ash or GGBFS in Cement.
2. Minimize Concrete consumption through innovative Architecture and Structural Design.
3. Use smart concrete mixture or i-crete as proportioning approach to save on cement in mix and better grading of combined aggregates & cohesive mix.
4. Consume optimum quantity of Cement in Concrete / Mortar mixtures by adding Pozzolanas in it.
Thus it will reduce emissions of CO2 and consumption of energy and raw materials. Replacement of such by-products can easily replace about 30-35 of cement volume. In addition, the service life of concrete structures can be improved by mixing cementitious materials in concrete as it will improve its impermeability.
II. Concept of Intelligent Buildings For Sustainable Development:
An intelligent or smart Building is the one that uses technology and processes to create space that is safer and more productive for its occupants and more operationally efficient for its owners. In such a building, network of electronic devises monitor and control the mechanical and lighting systems to reduce energy consumption and maintenance costs. Lighting is controlled with a system based on sensors, which can detect the presence of occupants and the relative darkness and modulate lights accordingly. Air handling units can mix outside air to regulate temperatures in various sections/rooms of the building. Sensors are placed in rooms and air-ducts to monitor temperatures. Such Buildings have hot water systems to supply heat to the building’s air handling units and chilled water systems to cool its air and equipment with sensors maintaining temperatures at optimum levels. They can also use Geothermal Energy for cooling or heating of Buildings. Intelligent buildings also have alarm system. While fire and smoke alarms are common, other types of alarms for reporting critical faults in the mechanical and electrical systems can also be effectively used. With such concepts, a quantum of energy can be saved and hence in the category of sustainable development.
A truly sustainable building construction should be energy efficient, incorporate concrete that contains the least amount of Portland cement and use of large amount of supplementary cementitious materials and recycled materials from waste materials. It should also optimize on the use of water & energy consumption and use non conventional energy & waste recyclable items.
III. Use of Waste Material in Construction Of Structures
Thus use of waste and recycled Materials for Construction of Building is desired. These may be used directly or indirectly or after processing. Some of such materials as follows:
- Air-Cooled Blast Furnace Slag
- By-Product Lime
- Fly Ash
- Glass Beads
- Ground Granulated Blast Furnace Slag
- Reclaimed Asphalt Pavement
- Recycled Concrete Material
- Steel Slag
- Recycled Steel Reinforcement
- Wet-Bottom Boiler Slag
- Old Tires / Crumb Rubber
- Waste Foundry Sand
- Glass Aggregate
A. How to Make Your Building Green in Cities:
There are more than 5,161 cities, towns and urban agglomerations in India where these provisions can help in reducing green house gases.
a. Provisions to be made before or during Construction to Make the Building green:
On these lines the Buildings in urban areas can be constructed and called green on the basis of provisions made and consumption of energy. Some criteria’s or suggestions are given below in two categories.
1. Ask Architect / Planner to plan your office / home’s orientation to the sun to harness energy or to shield it from heat.
2. High efficiency insulated glass windows can reduce requirements of energy during the operation or use of Building. Thus it will emit minimum carbon di- oxide.
3. Minimize concrete consumption through innovative architecture and Structural Design for optimum use of concrete.
4. Use smart concrete mixture proportioning approach to save on cement in concrete mix.
5. Consume less Cement in concrete / mortar mixtures.
6. Dual flush toilets will help conserve water with controlled water outlet options.
7. Non – toxic paints should be used on the walls. These use water rather than petroleum based solvents and do not emit smog producing pollutants.
8. Provide Rainwater Harvesting systems on the roof of Building to collect water, which can be used to flush Toilets or for general wash or recharge the ground.
9. Use Solar Panels to heat bath water and generate little electricity for use when there are power cuts instead of using Invertors.
10. Install Wind turbines on the roof, which can be used to generate electricity.
11. A rain garden can help reduce storm water runoff.
12. Use Native landscaping around building. This requires less water for irrigation and maintenance.
b. Provisions to be made After Construction or during its use to Make the Building green:
Some or all of the following provisions given below can be used to make the Building green.
1. Rainwater could be channeled into water buffs or ground recharging. Such water can be used to water plants or wash cars, floors etc.
2. Collect gray water from baths, sinks, kitchens and washing machines and use it to flush lavatories.
3. Motion detectors can be used to switch off lights, fans, AC’s etc, if there is no one in the room.
4. Install Sunlight detectors to Switch off / on the lights when they are not needed, especially on streets and office buildings.
5. Use Compact Fluorescent Light Bulbs (CFLs), which use 30% less energy than incandescent Bulbs.
6. Use Energy efficient appliances to reduce power use.
7. Use composting to reduce organic waste and help your garden at the same time. Most food scraps and biodegradable material produce nutrient rich fertilizer.
8. Collect all metals, glass, Polythene etc separately for reprocessing by appropriate industry.
9. Educate yourself, your children and your workers to use optimum amount of water and electricity.
B. How To Make Your Building Green in Rural Areas
Similar to planning of Buildings in urban areas, these can also be constructed in rural areas. Therefore, some or all of the following provisions given below can be used to make the Building green.
1. Plan your home’s orientation to the sun to harness energy or to shield it from heat.
2. Non – toxic paints should be used on the walls. These use water rather than petroleum based solvents and do not emit smog producing pollutants. Instead use lime wash to white wash the walls and roof.
3. Provide Rainwater Harvesting systems on the roof of Building to collect water, which can be used for general washing or for toilets.
4. Rainwater could be channeled into water buffs or ground recharging. Such water can also be used to water plants or floors etc.
5. Use Solar Panels to heat bath water or generate electricity for use when there are power cuts instead of using Invertors.
6. Install Sunlight detectors to Switch off / on the lights when they are not needed, especially on streets and office buildings.
7. Use Compact Fluorescent Light bulbs (CFLs), which use 30% less electricity / energy than incandescent Bulbs.
8. A rain garden can help reduce storm water runoff.
9. Use Native landscaping around building. This requires less water for irrigation and maintenance.
10. Use composting to reduce organic waste and help your garden at the same time. Most food scraps and biodegradable material produce nutrient rich fertilizer.
11. Collect all metals, glass, Polythene etc separately for reprocessing by appropriate industry.
12. Educate yourself and your children to use optimum amount of water and electricity.