GREEN BUILDING
GREEN BUILDING
J.THOMAS BRITTO(8807423228)
P.R.ENGINEERING COLLEGE
Abstract
Green building refers to a structure and using process that is
environmentally responsible and resource-efficient throughout a building's
life-cycle. The Green Building project differs from
conventional building projects by assigning equal priorities to economical,
social, and environmental goals. LCA
recognized that it is critical to the design of environmentally responsible
buildings. Research shows that such a
building improves tenants' satisfaction and health, enabling higher employee
productivity. As a result of the
increased interest in green building concepts and practices, a number of
organizations have developed standards, codes and rating systems conservation of water, energy, and building materials, and
occupant comfort and health.
Keywords: sustainability, life cycle assessment, photovoltaic
technique,
Introduction
Green building (also known as green construction or sustainable building) refers to a structure and using process that is environmentally
responsible and resource-efficient throughout a building's life-cycle: from site
selection to design, construction, operation, maintenance, renovation, and
demolition. This practice expands and complements the classical building design
concerns of economy, utility, durability, and comfort
Green building brings together a
vast array of practices and techniques to reduce and ultimately eliminate the
impacts of buildings on the environment and human health
Green buildings are designed to
reduce the overall impact of the built environment on human health and the
natural environment by:
§ Efficiently
using energy, water, and other resources
- Protecting occupant health and improving employee productivity
§ Reducing
waste, pollution and environmental degradation
A
similar concept is natural building, which is
usually on a smaller scale and tends to focus on the use of natural materials that are locally. Other related topics include sustainable design and green architecture.
Sustainability
Sustainability may be defined as meeting the
needs of present generations without compromising the ability of future generations
to meet their need. .
A 2009
report by the U.S. General Services Administration found 12 sustainably
designed buildings cost less to operate and have excellent energy performance.
In addition, occupants were more satisfied with the overall building than those
in typical commercial buildings.
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Reducing environmental
impact:
Green
building practices aim to reduce the environmental impact of buildings, and the
very first rule is, do not build in sprawl. No matter how much grass you put on
your roof, no matter how many energy-efficient windows, etc., you use, if you
build in sprawl, you've just defeated your purpose. Buildings account for a
large amount of land .According to the National Resource Inventory, approximately
107 million acres (430,000 km2) of land in the United States are
developed. The International Energy Agency released a publication that
estimated that existing buildings are responsible for more that 40% of the
world’s total primary energy consumption and for 24% of global carbon dioxide
emissions.
. It often emphasizes taking
advantage of renewable resources, e.g., using sunlight through passive
solar and active solar and photovoltaic techniques and using
plants and trees through green roofs, rain gardens, and for reduction of rainwater run-off.
Many other techniques, such as using packed gravel or permeable concrete
instead of conventional concrete or asphalt to enhance replenishment of ground
water, are used as well.
While the practices, or
technologies, employed in green building they may differ from region to region,
there are fundamental principles that persist from which the method is derived: Site selection and Structure Design Efficiency, Energy Efficiency, water efficiency , Materials efficiency, Indoor Environmental Quality Enhancement, Operations and Maintenance Optimization,
and Waste and Toxics Reduction. The essence of green building is an optimization of
one or more of these principles.
Life cycle
assessment (LCA)
A life cycle assessment assesses a full range
of impacts on environment associated with all the stages of a process from
cradle-to-grave taken into account include embodied energy, global warming
potential, resource use, air pollution, water pollution, and waste.
LCA
recognized that it is critical to the design of environmentally responsible
buildings.
Athena
software tools are especially useful early in the design process. They allow
designers to experiment with different material mixes to achieve the most
effective combination.
A more
product-oriented tool is the BEES (Building for Environmental and Economic
Sustainability) software, which combines environmental
measures with economic indicators to provide a final rating. Particularly
useful at the specification and procurement stage of a project, BEES 4.0
includes data on 230 products such as siding and sheathing.
Site
selection and structure design efficiency
The foundation of any construction project is rooted in the concept and
design stages. The concept stage, in fact, is one of the major steps in a
project life cycle, as it has the largest impact on cost and performance. In designing environmentally optimal buildings, the
objective is to minimize the total environmental impact associated with all
life-cycle stages of the building project. However, building as a process is
not as streamlined as an industrial process, and are much more complex
products, composed of a multitude of materials and components each constituting
various design variables to be decided at the design stage. A variation of
every design variable may affect the environment during all the building's
relevant life-cycle stages.
Energy Efficency
Green
buildings often include measures to reduce energy consumption – both the
embodied energy required to extract, process, transport and install building
materials and operating energy to provide services such as heating and power
for equipment.
To
reduce operating energy use, high-efficiency windows and insulation in walls,
ceilings, and floors increase the efficiency of the building envelope
. Another strategy, passive solar building design, is often implemented in low-energy
homes. Designers orient windows and walls and place awnings, porches, and trees
to shade windows and roofs during the summer while maximizing solar gain in the
winter. In addition, effective window placement can provide more natural light and lessen the
need for electric lighting during the day. Solar water
heating further
reduces energy costs.
Onsite
generation of renewable
energy through solar power
, wind power, hydro power, or biomass can significantly
reduce the environmental impact of the building. Power generation is generally
the most expensive feature to add to a building.
Water
efficiency
Reducing
water consumption and protecting water quality are key objectives in
sustainable building. One critical issue of water consumption is that in many
areas, the demands on the supplying aquifer exceed its ability to replenish
itself. To the maximum extent feasible, facilities should increase their
dependence on water that is collected, used, purified, and reused on-site. The
protection and conservation of water throughout the life of a building may be
accomplished by designing for dual plumbing that recycles water in toilet
flushing. Waste-water may be minimized by utilizing water conserving fixtures
such as ultra-low flush toilets and low-flow shower heads. Bidets help
eliminate the use of toilet paper, reducing sewer traffic and increasing
possibilities of re-using water on-site. Point of use water treatment and heating improves
both water quality and energy efficiency while reducing the amount of water in
circulation. The use of non-sewage and grey water for on-site use such
as site-irrigation will minimize demands on the local aquifer.
Materials
efficiency
Building materials typically considered to be 'green' include lumber
from forests that have been certified to a third-party forest standard, rapidly
renewable plant materials like bamboo and straw and other products that are non-toxic,
reusable, renewable, and recyclable (e.g., , Linoleum, sheep
wool, panels made from paper flakes, etc.) The EPA (Environmental Protection Agency) also suggests
using recycled industrial goods, Building materials should be extracted and
manufactured locally to the building site to minimize the energy embedded in
their transportation. Where possible, building elements should be manufactured
off-site and delivered to site, to increase benefits of off-site manufacture
including reduce waste, increase recycling high quality elements, better OHS
management, less noise and dust.
Indoor
environmental quality enhancement
The Indoor Environmental Quality (IEQ) category in LEED standards, one
of the five environmental categories, was created to provide comfort,
well-being, and productivity of occupants. The LEED IEQ category addresses
design and construction guidelines especially: indoor air quality (IAQ),
thermal quality, and lighting quality. Indoor Air Quality seeks to reduce volatile organic compounds, Buildings rely on a properly designed
ventilation system provide adequate
ventilation of cleaner air from outdoors or re-circulated, filtered air as well
as isolated operations from other occupancies. During the design and
construction process choosing construction materials and interior finish
products with zero or low VOC emissions will improve IAQ. Most building
materials and cleaning/maintenance products emit gases, some of them toxic, such
as many VOCs including formaldehyde. These gases can have a detrimental impact
on occupants' health, comfort, and productivity. Avoiding these products will
increase a building's IEQ. LEED, HQ and Green Star contain specifications on use of
low-emitting interior. Draft LEED 2012 is about to expand the scope of the involved products. BREEAM limits formaldehyde emissions, no other VOCs.
Also
important to indoor air quality is the control of moisture accumulation leading
to mold growth and the presence of bacteria and viruses as well as dust mites
and other organisms and microbiological concerns. Water intrusion through a
building's envelope. A well-insulated and tightly-sealed envelope will reduce
moisture problems but adequate ventilation is also necessary to eliminate
moisture from sources indoors including human metabolic processes, cooking,
bathing, cleaning, and other activities.
Personal
temperature and airflow control over the HVAC system coupled with a properly
designed building
envelope will also aid in increasing a building's thermal quality.
Solid
wood products, particularly flooring, are often specified in environments where
occupants are known to have allergies to dust or other particulates. Wood
itself is considered to be hypo-allergenic and its smooth surfaces prevent the
buildup of particles common in soft finishes like carpet
Interactions among all the indoor
components and the occupants together form the processes that determine the
indoor air quality
Operations
and maintenance optimization
No matter how sustainable a
building may have been in its design and construction, it can only remain so if
it is operated responsibly and maintained properly. Ensuring operations and
maintenance (O&M) Every aspect of green building is integrated
into the O&M phase of a building's life. The addition of new green
technologies also falls on the O&M staff. Although the goal of waste
reduction may be applied during the design, construction and demolition phases
of a building's life-cycle, it is in the O&M phase that green practices
such as recycling and air quality enhancement take place.
Waste
reduction
Green architecture also seeks to
reduce waste of energy, water and materials used during construction. For
example, in California nearly 60% of the state's waste comes from commercial
building. During the construction phase, one goal should be to
reduce the amount of material going to landfills.
Well-designed buildings also help reduce the amount of waste generated by the
occupants as well, by providing on-site solutions such as compost bins to reduce matter going
to landfills.
When
buildings reach the end of their useful life, they are typically demolished and
hauled to landfills. Deconstruction is a method of harvesting what is commonly
considered “waste” and reclaiming it into useful building material. Extending the useful life of a structure also reduces
waste – building materials such as wood that are light and easy to work with
make renovations easier.
To
reduce the impact on wells or water
treatment plants, several
options exist. "Grey water",
wastewater from sources such as dishwashing or washing machines, can be used
for subsurface irrigation, or if treated, for non-potable purposes, e.g., to
flush toilets and wash cars. Rainwater collectors are used for similar
purposes.
Conclusion
As a result of the increased interest in
green building concepts and practices, a number of organizations have developed
standards, codes and rating systems building professionals and consumers
embrace green building with confidence.
In some cases, codes are written so local governments can adopt them as
bylaws to reduce the local environmental impact of buildings.
Green
building rating systems such as BREEAM (United Kingdom), LEED (United States
and Canada), and CASBEE (Japan) help consumers to determine a structure’s level
of environmental performance.
They award credits for optional building features that support green
design in categories such as location and maintenance of building site.
Conservation of water, energy,
and building materials, and occupant comfort and health. The number of credits
generally determines the level of achievement
References
1.
Environmental Science and Engineering by Anubha Kaushik, C.P.Kaushik.
2 .www.osun.org
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