Green building
Green building refers to both a structure and the application of processes that are environmentally responsible and resource-efficient throughout a building's life cycle: from planning to design, construction, operation, maintenance, renovation, and demolition. This requires close cooperation between the contractor, the architects, the engineers, and the client at all project stages. The Green Building practice expands and complements the classical building design concerns of economy, utility, durability, and comfort. Green building also refers to saving resources to the maximum extent, including energy saving, land saving, water saving, material saving, etc., during the whole life cycle of the building, protecting the environment and reducing pollution, providing people with healthy, comfortable and efficient use of space, and being in harmony with nature. Buildings that live in harmony; green building technology focuses on low consumption, high efficiency, economy, environmental protection, integration and optimization.
Leadership in Energy and Environmental Design is a set of rating systems for the design, construction, operation, and maintenance of green buildings, developed by the U.S. Green Building Council. Other certification systems that confirm the sustainability of buildings are the British BREEAM for buildings and large-scale developments or the DGNB System which benchmarks the sustainability performance of buildings, indoor environments, and districts. Currently, the World Green Building Council is conducting research on the effects of green buildings on the health and productivity of their users and is working with the World Bank to promote green buildings in Emerging Markets through EDGE Market Transformation Program and certification. There are also other tools such as NABERS or Green Star in Australia, Global Sustainability Assessment System used in the Middle East and the Green Building Index predominantly used in Malaysia.
Building information modeling is a process involving the generation and management of digital representations of the physical and functional characteristics of places. Building information models are files which can be extracted, exchanged, or networked to support decision-making regarding a building or other built asset. Current BIM software is used by individuals, businesses, and government agencies who plan, design, construct, operate, and maintain diverse physical infrastructures, such as water, refuse, electricity, gas, communication utilities, roads, railways, bridges, ports, and tunnels.
Although new technologies are constantly being developed to complement current practices in creating greener structures, the common objective of green buildings is 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 2009 report by the U.S. General Services Administration found that 12 sustainably designed buildings cost less to operate and have excellent energy performance. In addition, occupants were overall more satisfied with these buildings than those in typical commercial buildings. These are eco-friendly buildings.
Reducing environmental impact
Buildings represent a large part of energy, electricity, water, and materials consumption. As of 2020, they account for 37% of global energy use and energy-related emissions, which the United Nations estimates contributed to 33% of overall worldwide emissions. Including the manufacturing of building materials, the global emissions were 39%. If new technologies in construction are not adopted during this time of rapid growth, emissions could double by 2050, according to the United Nations Environment Program.Glass buildings, especially all-glass skyscrapers, contribute significantly to climate change due to their energy inefficiency. While these structures are visually appealing and allow abundant natural light, they also trap heat, necessitating increased use of air conditioning systems, which contributes to higher carbon emissions. Experts advocate for design modifications and potential restrictions on all-glass edifices to mitigate their detrimental environmental impact.
Buildings account for a large amount of land. According to the National Resources Inventory, approximately of land in the United States are developed. The International Energy Agency released a publication that estimated that existing buildings are responsible for more than 40% of the world's total primary energy consumption and for 24% of global carbon dioxide emissions.
According to Global status report from the year 2016, buildings consume more than 30% of all produced energy. The report states that "Under a below 2°C trajectory, effective action to improve building energy efficiency could limit building final energy demand to just above current levels, meaning that the average energy intensity of the global building stock would decrease by more than 80% by 2050".File:Hanging gardens of One Central Park, Sydney.jpg|thumb|Hanging gardens of One Central Park, SydneyGreen building practices aim to reduce the environmental impact of building as the building sector has the greatest potential to deliver significant cuts in emissions at little or no cost. General guidelines can be summarized as follows: Every building should be as small as possible. Avoid contributing to sprawl, even if the most energy-efficient, environmentally sound methods are used in design and construction. Bioclimatic design principles are able to reduce energy expenditure and by extension, carbon emissions. Bioclimatic design is a method of building design that takes local climate into account to create comfortable conditions within the structure. This could be as simple as constructing a different shape for the building envelope or facing the building towards the south to maximize solar exposure for energy or lighting purposes. Given the limitations of city planned construction, bioclimatic principles may be employed on a lesser scale, however it is still an effective passive method to reduce environmental impact.
Goals of green building
The concept of sustainable development can be traced to the energy crisis and environmental pollution concerns of the 1960s and 1970s. The Rachel Carson book, Silent Spring, published in 1962, is considered to be one of the first efforts to describe sustainable development as related to green building. The green building movement in the U.S. originated from the need and desire for more energy efficient and environmentally friendly construction practices. There are a number of motives for building green, including environmental, economic, and social benefits. However, modern sustainability initiatives call for an integrated and synergistic design to both new construction and in the retrofitting of existing structures. Also known as sustainable design, this approach integrates the building life-cycle with each green practice employed with a design-purpose to create a synergy among the practices used.Green building brings together a vast array of practices, techniques, and skills to reduce and ultimately eliminate the impacts of buildings on the environment and human health. It often emphasizes taking advantage of renewable resources, e.g., using sunlight through passive solar, active solar, and photovoltaic equipment, and using plants and trees through green roofs, rain gardens, and reduction of rainwater run-off. Many other techniques are used, such as using low-impact building materials or using packed gravel or permeable concrete instead of conventional concrete or asphalt to enhance replenishment of groundwater.
While the practices or technologies employed in green building are constantly evolving and may differ from region to region, fundamental principles persist from which the method is derived: siting 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. Also, with the proper synergistic design, individual green building technologies may work together to produce a greater cumulative effect.
On the aesthetic side of green architecture or sustainable design is the philosophy of designing a building that is in harmony with the natural features and resources surrounding the site. There are several key steps in designing sustainable buildings: specify 'green' building materials from local sources, reduce loads, optimize systems, and generate on-site renewable energy.
Life cycle assessment
A life cycle assessment can help avoid a narrow outlook on environmental, social, and economic concerns by assessing a full range of impacts associated with all cradle-to-grave stages of a process: from extraction of raw materials through materials processing, manufacture, distribution, use, repair, and maintenance, and disposal or recycling. Impacts taken into account include embodied energy, global warming potential, resource use, air pollution, water pollution, and waste.In terms of green building, the last few years have seen a shift away from a prescriptive approach, which assumes that certain prescribed practices are better for the environment, toward the scientific evaluation of actual performance through LCA.
Although LCA is widely recognized as the best way to evaluate the environmental impacts of buildings, it is not yet a consistent requirement of green building rating systems and codes, despite the fact that embodied energy and other life cycle impacts are critical to the design of environmentally responsible buildings.
In North America, LCA is rewarded to some extent in the Green Globes rating system, and is part of the new American National Standard based on Green Globes, ANSI/GBI 01-2010: Green Building Protocol for Commercial Buildings. LCA is also included as a pilot credit in the LEED system, though a decision has not been made as to whether it will be incorporated fully into the next major revision. The state of California also included LCA as a voluntary measure in its 2010 draft Green Building Standards Code.
Although LCA is often perceived as overly complex and time-consuming for regular use by design professionals, research organizations such as BRE in the UK and the Athena Sustainable Materials Institute in North America are working to make it more accessible.
In the UK, the BRE Green Guide to Specifications offers ratings for 1,500 building materials based on LCA.