Green Building Glossary

Green Building Glossary

ambient lighting
Lighting in an area from any source that produces general illumination, as opposed to task lighting.

daylight factor (DF)
The ratio of daylight illumination at a given point on a given plane, from an obstructed sky of assumed or known illuminance distribution, to the light received on a horizontal plane from an unobstructed hemisphere of this sky, expressed as a percentage. Direct sunlight is excluded for both values of illumination. The daylight factor is the sum of the sky component, the external reflected component, and the internal reflected component. The interior plane is usually a horizontal workplane. If the sky condition is the CIE standard overcast condition, then the DF will remain constant regardless of absolute exterior illuminance.

Green building
The first Green Builder Program in the United States was created in 1991 in Austin, Texas. Pliny Fisk, the man behind that program defined green building or sustainable building in a most helpful way when he wrote:"Sustainability", according to Webster's American Heritage Dictionary, is to "keep in existence; maintain." As it relates to the world we live in, sustainability means meeting our present needs without compromising the needs of future generations. The sustainable approach recognizes the interaction of natural and technological systems on our planet, and seeks to minimize the adverse impacts of our everyday lives on the systems that support all life.

Sustainability implies that we look at and understand our local environment in terms of climate, natural resources, and human resources and improve our relationship with them without jeopardizing their future usefulness. Recognizing the nature of the interdependence of the human and natural environment is a key concept toward understanding sustainability. A sustainable approach encourages people to become a part of the natural flows and cycles of our world and not seeking to overpower them.


greenhouse effect
The Greenhouse Effect is a natural warming process of the earth. When the sun's energy reaches the earth some of it is reflected back to space and the rest is absorbed. The absorbed energy warms the earth's surface which then emits heat energy back toward space as longwave radiation. This outgoing longwave radiation is partially trapped by greenhouse gases such as carbon dioxide, methane and water vapour which then radiate the energy in all directions, warming the earth's surface and atmosphere. Without these greenhouse gases the earth's average surface temperature would be about 33 degrees Celsius cooler.

greenhouse gases (GHG)
Some Greenhouse Gases (or GHG) occur naturally in the atmosphere, while others result from human activities. Naturally occuring greenhouse gases include water vapor, carbon dioxide, methane, nitrous oxide, and ozone. Certain human activities, however, add to the levels of most of these naturally occurring gases. Carbon dioxide is released to the atmosphere when solid waste, fossil fuels (oil, natural gas, and coal), and wood and wood products are burned. Methane is emitted during the production and transport of coal, natural gas, and oil. Methane emissions also result from the decomposition of organic wastes in municipal solid waste landfills, and the raising of livestock. Nitrous oxide is emitted during agricultural and industrial activities, as well as during combustion of solid waste and fossil fuels. Very powerful greenhouse gases that are not naturally occurring include hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and sulfur hexafluoride (SF6), which are generated in a variety of industrial processes. greywaterGreywater (or Graywater) is defined as any wastewater, except in the toilet, produced from baths and showers, clothes washers, and lavatories in a home.

luminaire
A complete electric lighting unit, including housing, lamp, and focusing and/or diffusing elements; informally referred to as fixture.

mixed air
The mixture of outdoor air and return air in an HVAC system. When filtered and conditioned, mixed air becomes supply air.

radiant energy (radiation)
Energy traveling in the form of electromagnetic waves, measured in units of energy such as joules, ergs, or kilowatthours.

recycled material
Material that would otherwise be destined for disposal but is diverted or separated from the waste stream, reintroduced as material feed-stock, and processed into marketed end-products.

renewable energy
Renewable energy is an energy resource that is replaced rapidly by natural processes. Some examples of renewable energy resources are sunlight, wind, geothermal, micro scale hydropower, and wood. When you use some sunlight to warm your building, more is made almost immediately available. Water flowing in the river or creek is continually replaced by rainfall. If you chop down a tree and burn its wood in your campfire, it takes awhile for the forest to grow enough to replace that wood, but it will happen within your lifetime.

renewable energy technologies
Active, passive, and photovoltaic strategies integrated into building design.

return air
Air that has circulated through a building as supply air and has been returned to the HVAC system for additional conditioning or release from the building.

skylight
A relatively horizontal, glazed roof aperture for the admission of daylight.

solar radiation
The full spectrum of electromagnetic energy including visible light from the sun. When solar radiation strikes a solid surface or a transparent medium such as air or glass, some of the energy is absorbed and converted into heat energy, some is reflected, and some is transmitted. All three of these effects are important for effective passive solar design.

sustainable
The condition of being able to meet the needs of present generations without compromising those needs for future generations. Achieving a balance among extraction and renewal and environmental inputs and outputs, as to cause no overall net environmental burden or deficit. To be truly sustainable, a human community must not decrease biodiversity, must not consume resources faster than they are renewed, must recycle and reuse virtually all materials, and must rely primarily on resources of its own region.

tight buildings
Buildings that are designed to let in minimal infiltration air in order to reduce heating and cooling energy costs. In actuality, buildings typically exhibit leakage that is on the same order as required ventilation; however, this leakage is not well distributed and cannot serve as a substitute for proper ventilation .