Green Building Construction

Construction industry is one of the largest consumers of raw material and energy during its lifecycle and therefore has a profound impact on environment. Buildings not only protect us from extremes of nature, but they also affect the natural environment, human health and the economy. For example, to heat/cool and power our buildings, large amount of energy is consumed. This energy is obtained primarily by burning fossil fuels - oil, natural gas and coal – which generate significant amounts of carbon dioxide (CO₂), the most widespread greenhouse gas (GHG). With modernization, environmental impact of buildings is becoming more apparent. Buildings may be associated with the release of GHG in other ways, for example, construction and demolition debris that degrades in landfills may generate methane, and the extraction and manufacturing of building materials may also generate GHG emissions.

According to World Green Building Council (WGBC) "buildings use 32% of the world's resources in construction. They are responsible for around 40% of global energy use and generate up to 30% of global GHG emissions." Therefore, to slowdown the pace of global climate change, efforts are to be put in reducing the energy use and GHG emissions produced by buildings during its lifecycle. If we do life cycle analysis of the building then same could be summ- arized as shown in the Table 1.


For these adverse impacts of a building, "Green Building Construction" concept is gaining importance. Green Building Construction is the practice of creating structures using processes that are environmentally responsible and resource-efficient during design, construction, operation, maintenance, renovation and deconstruction of a building, i.e. throughout its lifecycle. This practice expands and complements the classical building design concerns of economy, utility, durability and comfort. Green Buildings are designed to reduce the overall adverse impact of the built environment on human health and natural environment by:

• Efficiently using/conserving/restoring energy, water and other resources
• Protecting occupant health and improving productivity
• Reducing waste, pollution, heat island effect and environmental degradation
• Optimize life cycle economic performance
• Enhance and protect biodiversity and ecosystems

So a Green Building or environment-friendly building inflicts minimal footprint on the environment and also enhances user comfort and efficiency. In general, Green Buildings tend to be more energy efficient, more durable, less costly to maintain and have better indoor air quality for health & productivity of its occupants. Green Building is also known as a sustainable or high performance building and reduces energy consumption in numerous ways. First, we can decrease the embodied energy (energy used to make any product, bring it to market, and dispose it off) of the building through efficient design, use of recycled and local materials, and recycling construction waste. Second, we can reduce energy consumption over lifetime by strategically placing windows (with overhangs, shading), doing plantation and use of skylights & solar/wind power. Practitioners of Green Building often try to achieve ecological and aesthetic harmony between a structure and its surrounding natural and built environment. This is in spite of the fact that the appearance and style of sustainable buildings is not necessarily different from their less sustainable counterparts.

Some Terms Related To Green Building

Sustainability in its environmental usages refers to the potential longevity of vital human ecological support systems and balance with the impacts of unsustainable design. As per the World Commission on Environment and Development, 1987 (U.N. Brundtland Report), it is "meeting the needs of present generations without compromising the ability of future generations to meet their needs." Green Buildings are for sustainability and will incorporate sustainable materials (reused, recycled, or made from renewable resources) in the construction; create healthy indoor environment with minimal pollutants (reduced harmful emissions); and/or feature landscaping that reduces water usage (e.g. by using native plants that survive without extra watering).

Sustainable Design (also referred to as "green design", "eco-design", or "design for environment") is the art of designing physical objects and the built environment to comply with the principles of sustainability. It ranges from the microcosm of designing small objects for everyday use, through to the macrocosm of designing buildings, cities, and the earth's physical surface.

Zero Net Energy Building is another popular term. It is for a building with zero net energy consumption and zero carbon emissions annually. However, many people have to live in zero-energy buildings e.g. hut, tent, cave, etc. out of necessity. Zero net energy buildings achieve one key Green Building goal of "reducing energy use and greenhouse gas emissions for the life of the building". Zero net energy buildings may or may not be considered "green" in all areas, such as reducing waste, using recycled building materials, etc. However, zero net energy buildings do tend to have a much lower ecological impact over the life of the building compared with 'Green Buildings' that require additional energy to be habitable and meet the needs of occupants. Natural Building, a similar concept, is usually on a smaller scale and tends to focus on the use of natural materials that are available locally.

How to Build a Green Building?

Effective Green Buildings are more than just a random collection of environment-friendly material & technologies. They require careful, systemic attention to the full life cycle impacts of the resources embodied in the building and to reduce consumption and pollution emissions over the complete life cycle of the building. This is accomplished through an integrated approach to architecture, blending design issues, use of energy-efficient materials, construction techniques, effective building systems and taking advantage of renewable energy supplies. Maximum benefit is achieved by implementing these from an early stage of the project. Environment-friendly architecture is a process that must be integrated into every phase of the construction project from beginning to end. To achieve true environment-friendly architecture, eco-friendly ideas need to be supported by everyone involved in the process from design to construction.


All buildings have the potential to become a Green Building. New buildings can be constructed with green method and operated to be Green Building. Existing buildings can also become green through remodeling, retrofitting and improved operations.

Economic Impact of a Green Building

Initially Green Building, when compared to conventional building, may seem expensive because the green building materials may cost more. However, actually there is money saved over its life because of lower operating and maintenance costs. These savings may be more apparent through life-cycle assessment (LCA). LCA is the science of measuring the environmental effects of a building "from cradle to grave," i.e. from extraction of the materials used to make the building to its ultimate disposal. The incremental initial cost for the first few Green Buildings in India can be found in the Table 2 (source Indian Green Building Council (IGBC)).


The declining incremental cost over the years is evident. Most Green Buildings may cost an extra of <2%, but are likely to yield up to 10 times as much over the entire life of the building. It means, integrating sustainable or "green" building practices into the construction of building is an investment. Resale values of Green Buildings are usually greater than the buildings which are conventionally built. When we consider the cost benefits of Green Building in terms of energy savings, worker productivity and safer indoor air quality for occupants, longevity of the building, environmental footprint, etc., then the initial expenses should not be a concern.

Also the integrated design processes towards Green Building can reduce even the initial costs. For example, in some cases, when buildings are carefully designed to be energy efficient, heating/ventilation/air conditioning equipment can be downsized for significant savings. There are also many locally available green products and materials that cost the same or even less than conventional ones.

Environment-friendly Green Building Materials

To determine whether a building is "green", we need to consider the building materials used, among other things. A Green Building shall use the products that are non-toxic, reusable, renewable and recyclable wherever possible. Green Building materials will have a lesser or reduced effect on human health and the environment when compared with competing products for the same purpose. It is generally agreed that using "Environment- friendly material" will

• Improve the health of the occupants
• Protect our natural ecosystems and resources
• Reduce energy consumption

Steel construction can be accepted as a very environment- friendly method as it presents a lot of positive environmental impacts w.r.t. sustainability, refurbishment, recyclability & reusability, and reducibility issues. The great majority of steel is available for recycle. Steel scrap, including everything from old cars to fridges and steel cans, is now a major component in production of new steel. Steel industry has always been a good recycler. The recycled content for steel used in metal roofs and walls, for example, is at ~ 20%. This high level of recycled content compared to other options, reduces both the cost and environmental impact of making new steel, as it conserves energy and other natural raw materials.

Usage of high strength steel reduces the input quantity. Also if quality coated steel is used, there is no need for replacement for a long time. Thus, quantity reduction during life cycle also happens because of longer life from usage of quality coated steel. Recyclability and reusability properties can become vital factors, if the waste management and landfill of building wastes becomes a problem. In addition, steel building

1. Reduces installation costs by increasing productivity (quicker with local labour) and using less energy and water,
2. Does not have adverse environmental impacts as there is no disturbance to local flora
3. Reduces the heat island effect because of lower thermal mass and good thermal reflecting properties of special coated steels

Most building products that are natural and non-toxic will be good for the indoor and outdoor environment (even though they may not be tolerated by some due to sensitivities). There is no question anymore about the positive effect of using non-toxic materials to reduce or eliminate indoor air pollution. Volatile organic compounds (VOCs) can adversely affect internal air quality. VOCs may result in short-term and long-term adverse human health effects, including triggering headaches and respiratory distress, and have been linked to some cancers. Formaldehyde has been linked to eye and throat irritation, nausea, asthma attacks in predisposed individuals and some cancers. Steel, the engineered material is likely to emit less VOCs, and in particular, less formaldehyde than other products performing the same function. Accordingly, using steel products is likely to result in better indoor air quality, protecting the health of building occupants.

Conclusion

Buildings are a major source of CO₂ emissions, and contribute around one-third of the same. For sustainability, construction of Green or sustainable building is becoming more important. By adopting strategies towards Green Building Construction, we can maximize both economic and environmental performance. So, we need to have well-designed, constructed, operated and maintained Green Buildings to have these benefits, which include reduced costs for energy, water, operation & maintenance and  improved occupant health & productivity. As per a study, Green Buildings can save up to 35% of the carbon emissions, 40% of water, 50% of energy, and 70% of solid waste during its lifetime. We can measure the energy and material savings, but it is more difficult to measure the benefits to our health and well being. As of now, there are ~ 130 nos. of IGBC certified Green Buildings in India which are not enough to make much of a dent on the larger scale. However, this will change as sustainability is no longer an option; instead it has become essential for survival in this resource-constrained world. With an increase in the number of Green Buildings, there is an expected rise in the opportunities for carbon credits, offsets and profits offered by these buildings. Steel with recyclability, reusability and reducibility characteristics is one of the Green Building materials most economically available to the construction industry today. Coated steel options have many environmental benefits including longer life, solar reflectance, no Lead (from usage of lead free paint for water harvesting), etc and are extensively used as construction material for buildings.