Green building, also known as sustainable building, refers to the environmentally responsible and resource-efficient processes used throughout a building's life-cycle beginning from site location through design, construction, operation, maintenance, renovation, and demolition.
The common objective of green buildings is to reduce the overall impact of the built environment on the natural environment by the efficient use of energy, water, and other resources and reducing waste, pollution and environmental degradation whilst protecting the users health and well-being.
Overview of green building
Green building brings together a vast array of practices, techniques and skills to reduce and ultimately eliminate the impact of buildings on the environment and human health. Obvious examples include using sunlight through passive solar, active solar, and photovoltaic equipment; using plants and trees through green roofs, rain gardens and reduction of rainwater run-off. The use of low-impact building materials or using packed gravel or permeable concrete instead of conventional concrete or asphalt to enhance replenishment of ground water are less obvious.
All green buildings are required to show optimal site and structure design, incorporating renewable building materials from local sources. Efficiencies in energy, water and materials, indoor environmental quality enhancement, operations and maintenance optimization, waste and toxics reduction and on-site renewable energy. With good design, individual green building technologies work together to produce a greater cumulative effect.
Life cycle assessment
A life cycle assessment (LCA) provides a broad outlook on environmental, social and economic concerns across all stages of the buildings life. It also looks at the buildings global warming potential, resource use, air pollution, water pollution, waste and more.
In the UK, Life Cycle Assessment methodologies support the Building Research Establishment Environmental Assessment Method (BREEAM) that confirms and certifies the sustainability of buildings and large scale developments.
Site and structure design efficiency
The concept stage of any construction has the largest impact on cost and performance since green building design aims to minimize the total environmental costs across all stages of the build. The challenge is that all building designs are unique, composed of a multitude of materials and
The challenge is that all building designs are unique, composed of a multitude of materials and components, each constituting various design variables to be decided at the design stage.
Green buildings often include measures to reduce energy consumption, from the extraction, processing, transport and installation of building materials to operating energy to provide heating and power.
As high-performance buildings use less operating energy through the use of solar power, wind power, hydro power or biomass, embodied energy (the materials used in the build) may account for one-third of the overall life cycle energy consumption.
To reduce operating energy use, designers use details to reduce air leakage, specifying high-performance windows and extra insulation in walls, ceilings, and floors. Passive solar building design with windows and walls strategically placed for maximum solar gain all year, with shading from awnings, porches and trees during the summer. 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.
Reducing water consumption and protecting water quality are key objectives in sustainable building. Green buildings incorporate facilities that increase dependence on water that is collected, used, purified, and reused on-site. Dual plumbing recycles water in toilet flushing. Waste-water may be minimized by utilizing water conserving fixtures such as ultra-low flush toilets and on-site irrigation. Point of use water treatment and heating improves both water quality and energy efficiency while reducing the amount of water in circulation.
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/or recyclable. For concrete a high performance self-healing concrete is available. Recycled industrial goods, such as foundry sand and demolition debris can also be used in construction projects.
Indoor environmental quality enhancement
Indoor Air Quality seeks to reduce volatile organic compounds and other air impurities such as microbial contaminants. Buildings rely on a properly designed ventilation system (passively/naturally or mechanically powered) to provide adequate ventilation of cleaner air from outdoors or recirculated, filtered air as well as isolated operations (kitchens, dry cleaners, etc.) from other occupancies.
Personal temperature and airflow control, coupled with a properly designed building envelope will increase a building's thermal quality, controlling damp and the risk of mould. Wood products can also improve air quality by absorbing or releasing moisture in the air to moderate humidity.
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. Operations and maintenance staff should establish best practices in energy efficiency, resource conservation, ecologically sensitive products and other sustainable practices to give an overview to users.
Green architecture seeks to reduce waste of energy, water and materials used during construction as well as the amount of waste generated by the occupants.
Deconstruction harvests "waste" and reclaims it into useful building material. Extending the useful life of a structure also reduces waste. Using timber makes renovations easier.
By collecting human waste at the source and running it to a semi-centralized biogas plant with other biological waste, liquid fertilizer can be produced, offsetting greenhouse gas emission.
Reduce impact on electricity network
When sustainable building features are designed, constructed and operated efficiently, peak demand can be reduced. Sustainable features include good orientation, sufficient indoor thermal mass, good insulation, photovoltaic panels, thermal or electrical energy storage systems and smart building home energy management systems.
Regulation and operation
A number of organizations have developed standards, codes and rating overview systems that let government regulators, building professionals and consumers embrace green building with confidence.
Green building rating systems such as BREEAM in the UK, help consumers overview a structure’s level of environmental performance. They award credits for optional building features that support green design in a range of categories. The number of credits generally determines the level of achievement.