Environmental Sustainability: Buildings and Construction Practices

This report provides a comprehensive overview of sustainable building practices, emphasizing their importance in mitigating environmental impacts. It explores the challenges and opportunities buildings present in terms of carbon emissions, energy consumption, and water usage. The report delves into the principles of green building design, highlighting the benefits such as reduced operating costs, improved occupant health, and enhanced building value. It examines various aspects of sustainable construction, including material selection, energy-saving features like insulation, high-performance windows, efficient HVAC systems, and passive solar design. The report also discusses water conservation strategies and the concept of integrated design, emphasizing the collaborative approach required for successful implementation. Furthermore, it highlights the importance of standards and certifications in promoting sustainable building practices.

SUSTAINABILITY AND BUILDINGS
Introduction
Buildings present a challenge and an opportunity for sustainable development. buildings account
for about 39% of the carbon dioxide emissions, 40% of primary energy use, and 72% of the
electricity consumption in the U.S. Additional information indicates that 14% of the potable
water consumption occurs in buildings. Globally, buildings are the largest contributors to carbon
dioxide emissions, above transportation and then industry. The construction of buildings requires
many materials that are mined, grown, or produced and then transported to the building site.
Buildings require infrastructure including roads, utility lines, water and sewer systems. People
need to be able to get to and from buildings to work, live, or take advantage of the services
provided within them. They need to provide a safe and comfortable environment for the people
that inhabit them.
It is possible to design and construct fully functional buildings that have far fewer negative
environmental impacts than current norms allow. Beyond benefitting the environment, green
buildings provide economic benefits including reduced operating costs, expanded markets for
green products and services, improved building occupant productivity, and optimized life-cycle
performance. Green buildings also offer social benefits that range from protecting occupant
comfort and health, to better aesthetic qualities, less strain on local infrastructure, and overall
improvement in quality of life.
In 1994, a group of experts was brought together to develop a pathway and specific principles for
sustainable development. According to these principles, building should be:
 Ecologically Responsive: The design of human habitat shall recognize that all resources
are limited, and will respond to the patterns of natural ecology. Land plans and building
designs will include only those with the least disruptive impact upon the natural ecology
of the earth. Density must be most intense near neighborhood centers where facilities are
most accessible.
 Healthy, Sensible Buildings: The design of human habitat must create a living
environment that will be healthy for all its occupants. Buildings should be of appropriate
human scale in a non-sterile, aesthetically pleasing environment. Building design must
respond to toxicity of materials, care with EMF, lighting efficiency and quality, comfort
requirements and resource efficiency. Buildings should be organic, integrate art, natural
materials, sunlight, green plants, energy efficiency, low noise levels and water. They
should not cost more than current conventional buildings.
 Socially Just: Habitats shall be equally accessible across economic classes.
 Culturally Creative: Habitats will allow ethnic groups to maintain individual cultural
identities and neighborhoods while integrating into the larger community. All population
groups shall have access to art, theater and music.

 Beautiful: Beauty in a habitat environment is necessary for the soul development of
human beings. It is yeast for the ferment of individual creativity. Intimacy with the
beauty and numinous mystery of nature must be available to enliven our sense of the
sacred.
 Physically and Economically Accessible: All sites within the habitat shall be accessible
and rich in resources to those living within walkable (or wheelchair-able) distance.
 Evolutionary: Habitats’ design shall include continuous re-evaluation of premises and
values, shall be demographically responsive and flexible to change over time to support
future user needs. Initial designs should reflect our society’s heterogeneity and have a
feedback system.
What is meant by a sustainable or green building? The U.S. EPA defines green building as “the
practice of creating structures and using processes that are environmentally responsible and
resource-efficient throughout a building’s life-cycle from siting to design, construction,
operation, maintenance, renovation and deconstruction. This practice expands and complements
the classical building design concerns of economy, utility, durability, and comfort.”
The benefits of sustainable buildings have already been documented. These buildings can reduce
energy use by 24-50%, carbon dioxide emissions by 33-39%, water use by 40%, and solid waste
by 70%. Green building occupants are healthier and more productive than their counterparts in
other buildings, and this is important because in the west, people spend an average of 90% or
more of their time indoors. Green buildings tend to have improved indoor air quality and
lighting.
There are also numerous perceived business benefits to green buildings, including decreased
operating costs and increased building value, return on investment, occupancy ratio, and rent
ratio.
Materials and Methods of Construction
It is frequently stated that the most sustainable building is the one that is not built. This does not
mean that we should not have buildings, but rather that we should make the most of our existing
buildings. Those buildings already have the infrastructure and have utilized many materials for
their construction.
A great deal of energy goes into making building materials. By volume, the major materials used
within the construction industry are crushed rock, gravel, sand, cement, cement concrete, asphalt
concrete, timber products, clay brick, concrete block, drywall, roofing materials, steel,
aluminum, copper and other metals, plastics, paper, paints, glues, and other chemical products.
The building industry has been the largest consumer of materials in the Nigeria.

The manufacturing of cement, for instance, is an enormous producer of greenhouse gas
emissions. Cement is made of about 85% lime by mass, which is mixed with other ingredients
such as shale, clay, and slate. It is formed into an inorganic adhesive by heating the ingredients to
a temperature of 1450 °C (2640 °F), and then grinding the product into a powder. Cement
comprises about 15% of concrete, which is made by mixing cement with sand, small rocks, and
water. Because it requires so much energy, the manufacture of cement is estimated to account for
as much as 5% of global anthropogenic greenhouse gas emissions.
Construction of buildings is also related to deforestation. Our consumption of wood to build
buildings and furniture over the centuries has resulted in the clearing of many old-world forests
and tropical forests. Trees are harvested not only for fuel but also for construction material and to
clear land for construction.
The demolition of old buildings to make way for new and construction projects themselves
generate huge amounts of waste. Careful deconstruction of buildings allows for reuse of
materials in future construction projects or for recycling of materials into new building (and
other) products. Deconstruction creates economic advantages by lower building removal costs
due to value of materials and avoided disposal costs, reduces impact to site on soil and
vegetation, conserves landfill space, and creates jobs due to the labor-intensity of the process.
Even when deconstruction is not possible, the waste can be recycled by sorting the materials
after they are collected and taken to a waste transfer station. Since new construction and
renovation requires the input of many materials, this is an opportunity to utilize products that
enhance the sustainability of the building. These products may be made of recycled content,
sustainably grown and harvested wood and pulp materials, products that have low emissions, and
products that are sourced locally. These products enhance the sustainability of the building by
supporting local economies and reducing the fuel needed to transport them long distances.
Energy-saving Building Features
Energy efficient measures have been around a long time and are known to reduce the use of
energy in residential and commercial properties. Improvements have been made in all of these
areas and are great opportunities for further innovation. Green buildings incorporate these
features to reduce the demand for heating and cooling.
Insulation
The building should be well insulated and sealed so that the conditioned air doesn’t escape to the
outside. Insulation can be installed in floors, walls, attics and/or roofs. It helps to have more even
temperature distribution and increased comfort as well.

High-performance Windows
Several factors are important to the performance of a window
 Thermal windows are at least double-paned and vacuum-filled with inert gas. This gas
provides insulation
 Improved framing materials, weather stripping and warm edge spacers reduce heat gain
and loss
 Low-E coating block solar heat gain in the summer and reflect radiant heat indoors
during the winter
Sealing of Holes and Cracks
Sealing holes and cracks in a building’s envelope as well as the heating and cooling duct systems
can reduce drafts, moisture, dust, pollen, and noise. In addition, it improves comfort and indoor
air quality at the same time it saves energy and reduces utility and maintenance costs.
Heating Ventilation and Air-conditioning (HVAC)
A large part of the energy consumption and thus environmental impact of a building is the
building heating, ventilation and air-conditioning (HVAC) systems that are used to provide
comfortable temperature, humidity and air supply levels. Buildings must be designed to meet
local energy code requirements, but these are often not as aggressive targets as they could be to
demand more energy efficiency.
There are many ways HVAC systems can be designed to be more efficient. Variable air volume
(VAV) systems increase air flow to meet the increase or decrease in heat gains or losses within
the area served. Having fans power down when not needed saves energy, as does reducing the
amount of air that needs to be conditioned and also reduces the need for reheat systems. These
systems are used to warm up an area if the cooled air supply is making an area too cold. VAV
systems can generally handle this by reducing air supply. All of this does need to be balanced by
making sure there is enough fresh air supply to meet the needs of the number of occupants in a
building. Otherwise, it will feel stuffy due to lack of air flow and oxygen.
Also using automated controls, whether it is a programmable thermostat in your home or a
building automation system (BAS) that uses computers to control HVAC settings based on
schedules and occupancy, can significantly reduce energy consumption.
The equipment itself can be made more energy efficient. For instance, new home furnaces range
in efficiency from 68-97%. Ideally, the most energy efficient furnace would be installed in a new
home

Passive Solar Design
This type of architectural design does not require mechanical heating and cooling of a building.
Instead it uses heating and cooling strategies that have been used historically such as natural
ventilation, solar heat gain, solar shading and efficient insulation. Figure Passive Solar Design
shows some of these elements. In the winter solar radiation is trapped by the greenhouse effect of
south facing windows (north in the southern hemisphere) exposed to full sun. Heat is trapped,
absorbed and stored by materials with high thermal mass (usually bricks or concrete) inside the
house. It is released at night when needed to warm up the building as it loses heat to the cooler
outdoors. Shading provided by trees or shades keeps the sun out in the hot months.
Lighting
Well-designed lighting can minimize the use of energy. This includes enhancing day lighting
(natural light), through windows, skylights, etc. Using energy efficient lighting such as compact
fluorescent light bulbs and LEDs (light-emitting diodes) can save energy as well. Using
occupancy sensors also means that lights will only be on when someone is in a room.
Water
Water usage can be minimized by using low-flow fixtures in restrooms, bathrooms, and kitchens.
Dual-flush toilets allow for the user to have the option of select less water (e.g. for liquid waste)
and more water (e.g. for solid waste) when flushing (Dual Flush Toilet). These have long been in
use in Europe, the Middle East and other places where water conservation is paramount. Fresh
water consumption can be reduced further through the use of greywater systems. These systems
recycle water generated from activities such as hand washing, laundry, bathing, and dishwashing
for irrigation of grounds and even for flushing toilets.
Integrated Design
Integrated design is a design process for a building that looks at the whole building, rather than
its individual parts, for opportunities to reduce environmental impact. Incremental measures
would include those approaches described above. To accomplish integrated design of a building,
all parties involved in the design–architects, engineers, the client and other stakeholders–must
work together. This collaborative approach results in a more harmonious coordination of the
different components of a building such as the site, structure, systems, and ultimate use.
Standards of Certification
Most countries establish certain standards to assure consistency, quality and safety in the design
and construction of buildings. Green building standards provide guidelines to architects,

engineers, building operators and owners that enhance building sustainability. Various green
building standards have originated in different countries around the world, with differing goals,
review processes and rating.
A good certification system should be developed with expert feedback. In addition, it should be
transparent, measurable, relevant and comparable.
Expert-based: Was input acquired from experts and professionals in the fields of design,
construction, building operation and sustainability?
Transparent: Is information readily available to the public about how buildings are rated?
Measurable: Does the rating system use measurable characteristics to demonstrate the extent of
sustainable design incorporated into the building? Does the system use life-cycle analysis to
evaluate?
Relevance: Does the rating system provide a “whole building evaluation” rather than an
evaluation of an individual design feature?
Comparable: Is the rating system able to compare building types, location, years, or different
sustainable design features?