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AAC blocks: Autoclaved Aerated Concrete blocks, precast structural products made with all natural raw materials. Ambient temperature: Temperature of the medium surrounding an object, often denoting prevailing room temperature. Aquifer recharge: The process by which rainwater seeps into the soil to an underlying aquifer instead of being evaporated, consumed, or otherwise discharged into streams, rivers, lakes, and oceans. Awnings: Passive solar building feature, overhang used for cooling and shading. B Backdrafting: When improper building pressurization causes a vented appliance to lose its chimney effect and causes dangerous combustion by-products to transfer into a building. Benefits of sourcing locally manufactured materials: Reducing projects carbon footprint, lowering embodied energy. Bioclimatic design: Interior and exterior architectural design that takes into account and utilizes local conditions, identifies and incorporates available passive energy and environmental systems, such as solar and wind energy, water flow, vegetation, landscaping and topographical features so as to provide thermal and atmospheric comfort for inhabitants. Biodiesel: Biodegradable, non-toxic, clean-burning fuel made from algae, vegetable oils, animal fats, and recycled restaurant greases, reduces harmful emissions by an average of 50% when substituted for petroleum diesel in most engines. Biomass: Refers to living and recently dead biological material which can be used as fuel or for industrial production. Biomimicry: A new discipline that studies nature's best ideas and then imitates these designs and processes to solve human problems. Bioswales: Stormwater treatment and conveyance feature designed to maximize time water travels through wide, shallow, and often meandering canals in order to filter maximum amounts of silt and pollution from surface runoff water, often incorporating biological components. Blower door test: Using a powerful fan mounted to an exterior door, this test measures a structure's air infiltration rate by comparing levels of pressurization from within the "sealed" environment and the outside. Brownfield: Property upon which its expansion, redevelopment, or reuse may be complicated by the presence or potential presence of a hazardous substance, pollutant, or contaminant. Cleaning up and reinvesting in these properties takes development pressures off of undeveloped, open land and both improves and protects the environment. BTU: One British Thermal Unit is the amount of heat energy needed to raise the temperature of one pound of water by one degree F. This measurement is used globally in the power, steam generation, and heating and air conditioning industries.
Building
commissioning:
Testing
and fine-tuning HVAC and other building systems to assure proper functioning and
adherence to design criteria. C Carbon dioxide: Chemical formula C02; colorless, odorless, powerful greenhouse gas directly impacting climate. Carbon monoxide: Chemical formula CO; colorless, odorless, tasteless, and highly toxic gas; the product of the incomplete combustion of carbon-containing compounds. Cementitious siding: Termite-resistant, water-resistant, non-combustible, autoclaved (cured with pressurized steam) siding composed of cement, sand, and cellulose fiber. Chlorofluorocarbons (CFCs): Compounds containing chlorine, fluorine and carbon only; formerly used widely in industry, as refrigerants, propellants, cleaning solvents, etc; contributes to damage to earth's ozone layer. Clay paint: Environmentally friendly paint, virtually odor free, yet can absorb odors and humidity, solvent free, hypoallergenic, anti static, chalk free with no know carcinogens or neuron-toxins. Climate Zones, EEBA: Used to determine appropriate building guidelines. According to EEBA (Energy and Environmental Building Association) there are 8: Sub Arctic/Arctic, Very Cold, Cold, Marine, Mixed Humid, Mixed Dry, Hot Dry, Hot Humid. Climate Zones, USDA: Used to project plant tolerance and survival, the USDA (United States Department of Agriculture) Hardiness Zone Map divides North America into separate zones; each zone is 10°F warmer (or colder) in an average winter than the adjacent zone. Commercial Building Deduction: The Energy Tax Incentives Act of 2005 (ETIA) Sec. 179D, deduction available for updating or constructing commercial building property to be more energy efficient. A tax deduction of up to $1.80 per square foot is available to owners or designers of new or existing commercial buildings that save at least 50 percent of the heating and cooling energy of a building that meets ASHRAE (American Society of Heating, Refrigerating and Air-Conditioning Engineers) Standards. Compact fluorescent bulbs (CFL): Designed to replace incandescent bulbs, CFLs use less energy and generally last longer. There is an estimated $30 savings in electricity compared to an incandescent lamp of the same lumen. Initial price is higher, and there is some controversy regarding the environmental effect of CFLs embodied energy and use of mercury. Composting toilet: Waterless (or virtually waterless) toilet fixture that converts human waste into a fertilizer or useable soil through the natural breakdown of organic matter back into its essential minerals, using aerobic bacteria and fungi. Compressive strength: The capacity of a material to withstand axially directed pushing forces, up to the point of being crushed. Conduction: Heat transfer from a region of higher temperature to one of a lower temperature, thus acting to even out temperature differences. Continuous hot water recirculation system: Common in hotels, these systems circulate hot water around the building continuously, eliminating water waste while waiting for hot water to reach tap; however, adds radiant heat to structure. Convection: Circulating heat transfer within liquids and gasses - like a chimney Cooling load: Mechanical systems should be designed to meet calculated peak load or a little lower. Cross ventilation: Ventilation obtained by having windows open on both sides of a room causing natural airflow across the space. D Daylighting: The practice of placing windows, or other transparent media, and reflective surfaces so that, during the day, natural light provides effective internal illumination. Drip line: Circle that could be drawn on the soil around a tree directly under the tips of its outermost branches. Dual flush toilet: Water conserving toilet fixture providing two handles or buttons for different gallons per flush rates, designed to differentiate gpf rates needed for liquid and solid waste. E Earth bermed construction: Designed to be partially buried under ground and/or to have dirt piled-up or "bermed" next to exterior walls and/or on the roof.
Earth
bricks:
Or
Compressed Earth Block (CEB); uniform earthen bricks compressed with
hand-operated or motorized hydraulic machines made with local materials. Ecosystems: A natural unit consisting of all of an area's plant, animal and micro organism life in conjunction with all the non-living physical factors of the environment. Introduction of new elements into an ecosystem tend to have a disruptive effect. In some cases, this can lead to ecological collapse. Edible landscaping: Designed landscapes using food-producing plants such as fruit and nut trees, berry bushes, vegetables, herbs and edible flowers as an alternative to conventional designs. Efficiency of fluorescent lights vs. incandescent lights: Compact fluorescents are 4 times more efficient. Efficiency of transportation modes in terms of BTU per passenger mile: Gaining in popularity, hybrid vehicles significantly reduce passenger's energy requirements per mile, mass transit and smaller engines can reduce those requirements even more, nearing non-motorized modes of transportation. Embodied energy: The amount of energy required to extract, process, transport and install a material, similar to life cycle.
EMF (Electromagnetic Fields):
A physical field produced by electrically charged objects, affects the behavior
of charged objects in the vicinity of the field, and extends indefinitely; one
of the four
fundamental forces of nature. Numerous scientific studies have produced
contradictory results about their effects. Some owners of green buildings may
express concern about EMF exposure from
transformers, circuit breaker box placement, rebar placement and electrical
wiring. Energy demand reduction methods: Can be accomplished by designing for actual use of occupants, increasing plug load efficiencies and reducing internal loads and gains through shell and lighting improvements.
Energy
Star:
Joint
program of the U.S. Environmental Protection Agency and the U.S.
Department of Energy designed to identify
and promote energy-efficient products to reduce greenhouse gas emissions.
Erosion control practices: Encourage on-site filtration and infiltration to decrease stormwater runoff, prevent unnecessary clearing and minimize grading; mulch and stabilize disturbed areas, erect silt fencing on perimeter.
Ethanol:
Flammable, colorless, slightly toxic chemical compound with a distinctive
perfume-like odor; the largest single use of ethanol is as a motor fuel and fuel
additive. Ethanol is produced from corn, but can also be produced from other
sources such as switch grass and sugar cane. Exterior uplighting: Exterior lighting shining upwards; contributes to light pollution and light trespass. Extraction: Process of removing a product or element from the environment to be used or processed. F Fiberglass batts: Insulation rolls available in widths suited to standard spacing of wall studs, and attic or floor joists. Most common type of insulation, available with or without vapor barrier facing. Financial benefit of green buildings: Improved occupant performance, reduced absenteeism and turnover, increased sales, lower operational costs, tax incentives, corporate image, global stewardship. Flyash: Mineral residue resulting from the combustion of coal in electric generating plants recycled and used as a high-performance substitute for Portland cement or as clinker for Portland cement production. Forest Stewardship Council (FSC): A non-profit, third party certification program that gives assurance that wood products are harvested from forests that are managed in an environmentally and socially responsible manner. Full cost accounting: A tool to identify, quantify and allocate the direct and indirect environmental costs of ongoing company operations. Full cost accounting helps identify and qualify the following four types of costs for a product, process or project: direct costs; hidden costs; contingent liability costs; and less tangible costs. See also Life Cycle Assessment (LCA). Full cutoff lighting: Describes luminaries that have no direct uplight (no light emitted above horizontal). Limits spill light onto adjacent property, reduces glare. No light is emitted directly from the luminaire into the sky. G Glazing, best orientation of walls: By facing the long side of a structure to the south and the short sides to the east and west, the building will capture solar heat in the winter and block solar gain in the summer. Although it is best to face the structure directly into the sun, it can be oriented up to 30 degrees away from due south. Granulated blast furnace slag: When crushed or milled to very fine cement-sized particles, ground granulated blast furnace slag (GGBFS), primarily from iron, iron ore and iron scrap, has cementitious properties, which make a suitable partial replacement for or additive to Portland cement. Graywater: Non-industrial wastewater generated from domestic processes such as washing dishes, laundry and bathing. Green roofing techniques and products: Also know as vegetated roofs. Many use sedum plants in lightweight soil; have medium-slow rate of water run-off and provide some cooling. Green Seal Certification: A non-profit organization that provides, third-party, science-based environmental certification standards for products and services. H
Heat
Gain Reduction Shading Strategies:
Selectively placing deciduous trees, fabric awnings and vine-covered pergola (or
trellis) on the south and west sides of structures. Interior window shades are
not generally effective. I Indoor air quality (IAQ), problems: VOCs from paints, sealers and adhesives; dust, pet dander, pollens and formaldehyde in engineered wood products.
Insulated Concrete Forms (ICFs):
A solid,
flat, steel-reinforced cast-in-place concrete wall, with
a concrete thickness of between 4 and 10
inches that acts as the structural component of the wall assembly. ICFs are used
in commercial and residential construction for exterior and interior, load-bearing
and non-load-bearing, and above-grade and below-grade walls. Specific
applications include frost walls, basement walls, storm shelters, demising
walls, slab-on-grade walls, non-load-bearing walls on post-tensioned floor
slabs, and single-story to multi-story walls. LEED® AP: LEED Professional Accreditation distinguishes building professionals with the knowledge and skills to successfully steward the integrated design and LEED certification process. LEED Accredited Professionals have demonstrated a thorough understanding of green building practices and principles and familiarity with LEED requirements, resources, and processes. LEED® Certification: Leadership in Energy and Environmental Design (LEED®) - Green Building Rating System, developed by the U.S. Green Building Council (USGBC), provides a suite of standards for environmentally sustainable construction. Since its inception in 1998, LEED has grown to encompass over 6,000 projects in 28 countries covering 1 billion square feet of development area. The hallmark of LEED is that it is an open and transparent process where the technical criteria proposed by the LEED committees are publicly reviewed for approval by the more than 8,500 membership organizations that currently comprise the USGBC. LEED has focused primarily on the certification of commercial structures and is currently piloting a residential certification. LEED-EB®: Leadership in Energy and Environmental Design for Existing Buildings (includes schools, laboratories, hotels, office buildings, etc.). LEED - for Homes ® (LEED-H®): Leadership in Energy and Environmental Design for Homes currently in a pilot phase scheduled to launch in 2007). LEED-NC®: Leadership in Energy and Environmental Design for New Construction of commercial and institutional buildings (includes schools, laboratories, hotels, office buildings, etc.). Life Cycle Assessment: Life-cycle assessment (LCA) is a process of evaluating the effects that a product has on the environment over the entire period of its life thereby increasing resource-use efficiency and decreasing liabilities. It can be used to study the environmental impact of either a product or the function the product is designed to perform. LCA is commonly referred to as a "cradle-to-grave" analysis. LCA's key elements are: (1) identify and quantify the environmental loads involved; e.g. the energy and raw materials consumed, the emissions and wastes generated; (2) evaluate the potential environmental impacts of these loads; and (3) assess the options available for reducing these environmental impacts. Light pollution: Light pollution is excess or obtrusive light created by humans. Among other effects, it disrupts ecosystems, can cause adverse health effects, obscures stars to city dwellers, interferes with astronomical observatories, and wastes energy. The International Dark-Sky Association estimates that each year in the United States, over $1 billion dollars is spent to generate this wasted light. Linseed oil: A yellowish oil extracted from the seeds of flax and used as a drying oil in paints and varnishes and in linoleum. Living building: Buildings that are built to operate as elegantly and efficiently as a natural organism such as a flower: 1) informed by the eco-region's characteristics 2) generates all of its own energy with renewable resources, 3) captures and treats all of its water on site and 4) uses resources efficiently, and for maximum beauty. Living roof: A roof of a building that is partially or completely covered with vegetation and soil, or a growing medium, planted over a waterproofing membrane. The rooftop garden conserves energy and preserves the environment. Living roofs provide extra insulation that reduce the amount of heating and cooling needed inside a building. They also reduce storm water runoff, which improves water quality. Living wall: A wall that is a vertical garden. Plants are rooted in fibrous material anchored to the wall. Water trickles down between the sheets and feeds moss, vines and other plants. Bacteria on the roots of the plants metabolize air impurities such as volatile organic compounds. Locally produced materials and processing: Under LEED standards local is currently defined as within a 500 mile radius.
Louvers:
Shading
devices, often adjustable, installed on a building's exterior, interior or
within specialized window and door products. Low-flow showerhead: Low-flow shower heads and faucet aerators reduce water consumption and energy cost of heating the water by as much as 50%. M Material selection criteria: Macro environmental effects (effects on land, water and air); Health (impacts on producers, installers and occupants); Energy (efficiency and embodied energy); Waste (reusing and recycling materials, durability and waste management) and Affordability (cost competitiveness, given integrated design).
Methane:
A greenhouse gas 23 times more powerful than carbon dioxide. Methane is emitted
from a variety of both human-related and
natural sources. Human-related activities include fossil fuel production,
animal husbandry, rice cultivation, biomass burning, and waste management.
These activities release significant
quantities of methane into the atmosphere. It is estimated that 60% of
global methane emissions are related to human-related activities. Natural
sources of methane include wetlands, gas hydrates, permafrost, termites, oceans,
freshwater bodies, non-wetland soils, and other sources such as wildfires.
Mold
contributors:
When
excessive moisture or water accumulates indoors, mold growth will often occur,
particularly if the moisture problem remains undiscovered or unaddressed. Indoor
mold growth can be greatly reduced or eliminated by controlling moisture (other
mold growth factors are cellulose, temperature, oxygen and fungal spores). Molds
and fungi grow best in the relative humidity (RH) range of 70% to 100%. Site
drainage issues, number and activity of the occupants and presence and location
of a wall vapor barrier are also important factors.
Mulching: A protective cover placed over the soil to promote stabilization and inhibit unwanted plant growth. Use mulch from organically certified sources when available and specify mulch without invasives.
Multifunction rooms:
A design
and building technique that can reduce the size of the building while giving
occupants a pleasing sense of space. For example a foyer may serve as an air
lock, storage area and mud room.
National
Fenestration Rating Council (NFRC):
A
non-profit organization that administers a national rating and labeling system
for the energy performance of windows, doors, skylights. Natural ventilation rates: Natural ventilation systems rely on pressure differences to move fresh air through buildings. Pressure differences can be caused by wind or the buoyancy effect created by temperature differences or differences in humidity. Net metering: Under net metering, a system owner receives retail credit for at least a portion of the electricity they generate, usually from qualified renewable resources such as wind or solar. Contact your local power company for details. Nitric oxide sources: Primary human-related sources of N20 are agricultural soil management, animal manure management, sewage treatment, and mobile and stationary combustion of fossil fuel. Nitric oxide is considered a greenhouse gas. Non-native plants: Plant species that are not indigenous to a given place or area and instead have been accidentally or deliberately transported to a new location by human activity. Non-native plants that cause damage to the ecosystem are called invasive. Invasives are a major cause of habitat destruction. Non-potable water: Water that is not used for drinking. Sources of non-potable water volumes include captured rainwater, graywater from building systems (e.g. sinks and showers), and municipal recycled water. Non-renewable energy source: Nonrenewable energy sources come out of the ground as liquids, gases and solids. Oil, gas, coal and uranium are examples. These energy sources are considered nonrenewable because they can not be replenished (made again) in a short period of time. Renewable energy sources can be replenished naturally in a short period of time. O Off-peak cooling: OPC units cool water, sometimes freezing it, for later use to cool air. The process can save on energy requirements and save money on electric rates by shifting load demands.
On-site
renewable energy:
Renewable energy is derived from the sun, wind, water, or the Earth's core. It
also can be derived from biomass—or plant matter—which is grown, harvested, and
transferred into energy by one of a number of processes. On-site renewable
energy is produced at a given organization's facilities and therefore has
negligible transportation costs and impacts. Examples are daylighting, passive
solar heating, natural ventilation, solar photovoltaic panels, solar thermal
panels, wind turbines, geothermal heating and cooling and fuel cells. Overhangs: In passive solar building design, exterior roof overhangs provide a practical method for shading building elements such as windows, doors, and walls. Ozone layer: The stratospheric ozone layer protects life on earth from the sun's ultraviolet (UV) radiation, which kills normal living cells. Chlorine compounds such as chlorofluorocarbons (CFCs) and other ozone layer destroyers such as nitrous oxide have been found to be rapidly increasing in the atmosphere in recent years. The main source of the increases in ozone destroying chemicals in the stratosphere appears to be man-made sources such as CFCs (used as blowing agents and refrigerants), HCFCs (used as blowing agents and refrigerants), and halons (used in fire extinguishers). P Passive cooling principles: Passive cooling can be used to reduce, and in some cases eliminate, mechanical air conditioning requirements in areas where cooling is a dominant problem. Natural cooling, heat gain control and convective cooling are often cited as passive cooling principals. Passive-solar heating: A system of features incorporated into a building's design to use and maximize the effects of the sun's natural heating capability. Passive solar heating systems may use a collection and storage element, such as a water-filled partition, which is exposed to the sun during the day and radiates heat to the structure at night. Other features, such as south-facing windows, site orientation, roof overhangs, are included to enhance the effects of the sun's heat. In a passive-solar heated building in the Northern hemisphere, larger appropriately-shaded window areas should be on the south side. Peak Oil: The date when the peak of the world's petroleum (crude oil) production rate is reached. It is widely anticipated that global production of oil will peak within the next 5 to 20 years. Pervious materials: Materials that permit water to enter the ground by virtue of their porous nature or by large spaces in the material. Examples are pervious concrete pavement, porous asphalt, gravel, crushed stone, and open paving blocks. Photovoltaic cell (PV cell): A specialized semiconductor diode that converts visible light into direct current (DC). Photovoltaic cells are an integral part of solar-electric energy systems, which are becoming increasingly important as alternative sources to utility power. Portland cement: An essential ingredient in concrete, accounts for approximately 7% of human caused carbon dioxide production (carbon dioxide is a greenhouse gas). Potable water: Drinkable water. Pozzolan: a material that reacts with Portland cement hydration products to produce cement-like qualities. The following pozzolans have the potential to replace a percentage of the Portland cement in a typical concrete mix: granulated blast furnace slag, silica fume, flyash and rice hull ash. Primary modes of heat transfer: Conduction, convection, and radiation. R Radiant hydronic heating systems: Uses conduction and radiation as a heating strategy. Radiation: Heat transfer away from objects - like a radiator. Relative humidity preferred by molds and fungi: Molds and mildews take 1-2 days to form in 70-100% humidity. Renewable Energy Credits (RECs): Also known as Green Tags, Renewable Energy Certificates, or Tradable Renewable Certificates (TRCs) are the property rights to the environmental benefits from generating electricity from renewable energy sources. These certificates can be sold and traded and the owner of the REC can legally claim to have purchased renewable energy. While traditional carbon emissions trading programs promote low-carbon technologies by increasing the cost of emitting carbon, RECs incentivize carbon-neutral renewable energy by providing a subsidy to electricity generated from renewable sources. Retention ponds: Type of constructed wetland that is used to contain stormwater or rain runoff. A retention basin provides an area to hold water from a small surrounding drainage area that would otherwise flow into other areas, allowing the water to remain in the local area. Reverse osmosis: A separation process that uses pressure to force a solvent through a membrane that retains the solute on one side and allows the pure solvent to pass to the other side. Reverse osmosis is the most common method of desalination. Roof catchment: The practice of collecting roof rainwater runoff and storing the water in barrels, tanks, cisterns, or ponds for use in landscape irrigation. (Also known as rainwater harvesting and rainwater catchment). R-values of insulation materials: Ability of material to resist the passage of temperature. S Silica fume: A fine-particulate waste product of electric-arc furnaces, its most important use is in the production of high-strength concrete.
Silt fencing:
A temporary sediment barrier made of woven synthetic filtration fabric installed
to
prevent
sediment from leaving the site and entering natural drainage way.
Solar
Heat Gain Coefficient (SHGC):
A
fraction of solar radiation admitted through a window. door, or
skylight—transmitted directly and/or absorbed, and subsequently released as heat
inside a building. The lower the SHGC, the
less solar heat it transmits and the greater its shading ability.
Stack-effect ventilation:
The
movement of air into and out of buildings, chimneys, flue gas stacks, or other
containers; and is driven by buoyancy. Buoyancy occurs due to a difference in
indoor-to-outdoor air density resulting from temperature and moisture
differences. The result is either a positive or negative buoyancy force.
The greater the thermal difference and the height of the structure, the greater
the buoyancy force, and thus the stack effect. The stack effect is also referred
to as the "chimney effect", and it helps drive natural ventilation and
infiltration. Stormwater runoff: Unfiltered water that reaches natural waterways by means of flowing across impervious or flooded surfaces. Sustainability: Meeting the needs of the present generation without compromising the ability of future generations to meet their own needs, a principle that guides society's actions to protect the environment and resources for future generations. T Tankless or on-demand water heater: Powered by gas or electricity, hot water comes out instantly, whenever it is needed, rather than being stored in a tank. In addition to saving energy, these units also are space-efficient. Thermal bridging: Ability of temperature to move through walls via metal bypassing. Thermal mass: A material that absorbs heat from a heat source, and then releases it slowly. Common materials used as a thermal mass include adobe, mud, stones, or even tanks of water. Within the context of radiant floors, a thermal mass is generally a thick concrete pad that is heated, either from pipes carrying hot water or from a mesh of electric wires. The concrete heats and cools slowly, which protects the room (and the people walking in it) from quick temperature swings. A further advantage is that you may be able to heat the concrete pad at night when electricity rates are low. The pad will then release its heat during the more expensive daylight hours without needing additional electricity. Radiant heating and hot water heating can also be supplied using solar thermal panels. Topsoil: The upper part of the soil. An inch of topsoil takes 50 to 1,000 years to develop. Topsoil can be preserved by minimizing site clearing, stockpiling scraped topsoil, covering it away from trees and confining construction machinery to established areas, staging areas and routes on site. Transpiration: The evaporation of excess water from aerial parts of plants, especially leaves but also stems, flowers and fruits. Increasing the number of urban parks and street trees in a city can offset the local heat effects of global warming. Urban areas can be significantly warmer than more rural surroundings due to the heat given off by buildings, roads and traffic, as well as reduced evaporative cooling, in what is commonly referred to as the 'heat island effect or urban island effect. TTF Tropical Forest Foundation is a non-profit, educational institution dedicated to the conservation of tropical forests through sustainable forestry. TFF has become widely recognized for establishing demonstration models and training schools to show the advantages and teach the principles of sustainable forest management/Reduced-Impact Logging. The Foundation's Board of Directors includes representatives from industry, government, science, academia, and conservation. Each member has an interest in seeing tropical forests renewed and sustained. U USGBC: United States Green Building Council.
UV
light:
Electromagnetic radiation with a wavelength shorter than that of visible light,
but longer than soft X-rays. Used for water and air filtration and purification,
because of its ability to destroy bacteria, viruses, toxic mold, tobacco
smoke, chlorine, heavy metals and hazardous fumes.
V Vapor diffusion retarders: A vapor barrier or vapor diffusion retarder (VDR) is a material that reduces the rate at which water vapor can move through a material. The older term "vapor barrier" is still used even though it may inaccurately imply that the material stops all of the moisture transfer. Since most materials allow some water vapor to diffuse through it to some degree, the term "vapor diffusion retarder" is more accurate. Vegetated swales: Low-impact stormwater management design feature using open shallow channels filled in with vegetation, usually thick grass, helps to trap pollutants, reduce the velocity of stormwater runoff; and increase on-site ground absorption. Visible Light Transmittance: A measure of the amount of visible light that passes through glazing material of a window. A product with a higher VT transmits more visible light. VT is expressed as a number between 0 and 1. The VT you need for a window, door, or skylight should be determined by daylighting requirements and/or whether reduced interior glare in a space is desirable. W Wall vapor barrier: See vapor diffusion retarder. Water infrastructure: Drinking water treatment plants, sewer lines, distribution lines and storage facilities. Waterless urinal: Sealed layer of liquid allows urine to pass through but continuously seals the drainage from the atmosphere, preventing odors from emerging; no waterlines need to be connected to fixture and few mechanical components to maintain. X Xeriscaping: Landscapes that are indigenous to a region requiring little or no maintenance, water, fertilizers or pesticides; designed to reflect native planting conditions. Z Zero-clearance fireplace: Units that displace, contain, or convect generated heat such that it allows the fireplace to be immediately adjacent to framing. |