Flood PlainA strip of relatively flat and normally dry land alongside a stream, river, or lake that is covered by water during a flood.
FloodplainAny land area susceptible to being inundated by floodwaters from any source.
FloorAction "on the floor" is that which occurs as part of a formal session of the full Senate.
Floor Area Ratio (FAR)A measure of development intensity. FAR is the ratio of the amount of floor area of a building to the amount of area of its site.
Floor SpaceThe interior area of a building, calculated in square feet or meters.
FloraPlants, especially those of a specific region, considered as a group.
Flow ConditionIn reference to solar thermal collectors, the condition where the heat transfer fluid is flowing through the collector loop under normal operating…
Flow ImproversA chemical used in fuel to reduce friction and increase performance.
Flow rateThe amount of water that moves through an area (usually pipe) in a given period of time.
Flow RestrictorA water and energy conserving device that limits the amount of water that a faucet or shower head can deliver.
FLPMAFederal Land Policy and Management Act of 1976.
FlueThe structure (in a residential heating appliance, industrial furnace, or power plant) into which combustion gases flow and are contained until they are…
Flue GasThe gas resulting from the combustion of a fuel that is emitted to the flue.
FluffingThe practice of installing blow-in, loose-fill insulation at a lower density than is recommended to meet a specified R-Value.
fluidized bedA gasifier or combustor design in which feedstock particles are kept in suspension by a bed of solids kept in motion by a rising column of gas.
Fluidized Bed Combustion (FBC)A type of furnace or reactor in which fuel particles are combusted while suspended in a stream of hot gas.
Fluidized-bed boilerA large, refractory-lined vessel with an air distribution member or plate in the bottom, a hot gas outlet in or near the top, and some provisions for…
Fluorescent LightThe conversion of electric power to visible light by using an electric charge to excite gaseous atoms in a glass tube.
FluvialPertaining to a river. Fluvial sediments are deposited by rivers.
Fly ashThe fine particulate matter entrained in the flue gases of a combustion power plant.
FlywayA seasonal route followed by birds migrating to and from their breeding areas.
Flywheel EffectThe damping of interior temperature fluctuations by massive construction.
Foam (Insulation)A high R-value insulation product usually made from urethane that can be injected into wall cavities, or sprayed onto roofs or floors, where it expands…
Foam BoardA plastic foam insulation product, pressed or extruded into board-like forms, used as sheathing and insulation for interior basement or crawl space walls…
Foam Core PanelsA type of structural, insulated product with foam insulation contained between two facings of drywall, or structural wood composition boards such as…
Foot CandleA unit of illuminance; equal to one lumen per square foot.
Foot PoundThe amount of work done in raising one pound one foot.
FootprintThe land or water area covered by a project. This includes direct physical coverage (i.e.
ForageSmall baitfish, crayfish and other creatures that bass or other predator fish eat.
ForbsHerbaceous (nonwoody), broad-leaved flowering plants; non-graminoid (grasses, sedges, and rushes) herbaceous plants. See also Graminoid herbaceous
ForceThe push or pull that alters the motion of a moving body or moves a stationary body; the unit of force is the dyne or poundal; force is equal to mass time…
Forced Air System or FurnaceA type of heating system in which heated air is blown by a fan through air channels or ducts to rooms.
Forced VentilationA type of building ventilation system that uses fans or blowers to provide fresh air to rooms when the forces of air pressure and gravity are not enough…
Forest healthA condition of ecosystem sustainability and attainment of management objectives for a given forest area.
Forest PlanThe document that sets goals, objectives, desired future condition, standards and guidelines, and overall programmatic direction for a National Forest.
Forest residuesMaterial not harvested or removed from logging sites in commercial hardwood and softwood stands as well as material resulting from forest management…
Forested areas or landAny land that is capable of producing or has produced forest growth or, if lacking forest growth, has evidence of a former forest and is not now in other…
forestry residuesIncludes tops, limbs, and other woody material not removed in forest harvesting operations in commercial hardwood and softwood stands, as well as woody…
formThe mass or shape of an object or objects that appears unified, such as a vegetative opening in a forest, a cliff formation, or a water tank.
Formaldehyde(for-MAL-duh-hide) A chemical used in manufacturing and chemical industries, and as a preservative by anatomists, embalmers, and pathologists.
Forward price curveThe set of prices of contracts for delivery of a good over a span of time in the future.
ForwarderA self-propelled vehicle to transport harvested material from the stump area to the landing.
FossilRemains of ancient life forms, their imprints or behavioral traces (e.g., tracks, burrows, or residues) and the rocks in which they are preserved.
Fossil fuelSolid, liquid or gaseous fuels formed in the ground after millions of years by chemical and physical changes in plant and animal residues under high…
Fossil FuelsFuels formed in the ground from the remains of dead plants and animals. It takes millions of years to form fossil fuels.
FragmentationProcess by which habitats are increasingly subdivided into smaller units, resulting in their increased insularity as well as losses of total habitat area.
Fragmentation of habitatThe breaking up of a single habitat area into two or more smaller habitat patches that are separated from each other.
Frame (Window)The outer casing of a window that sits in a designated opening of a structure and holds the window panes in place.
FramingThe structural materials and elements used to construct a wall.
Francis TurbineA type of hydropower turbine that contains a runner that has water passages through it formed by curved vanes or blades.
FreonA registered trademark for a cholorfluorocarbon (CFC) gas that is highly stable and that has been historically used as a refrigerant.
FrequencyThe number of cycles through which an alternating current passes per second; in the U.S.
Fresnel LensAn optical device for concentrating light that is made of concentric rings that are faced at different angles so that light falling on any ring is focused…
FriableA term commonly used to describe a crumb-like callus. In this state, the callus is easily dissected and readily dispersed into single cells or clumps of…
Friction HeadThe energy lost from the movement of a fluid in a conduit (pipe) due to the disturbances created by the contact of the moving fluid with the surfaces of…
FrontageThe continuous linear distance along any approved way, measured on the street line, between the side lot lines.
Fuel cellA holding tank for a race car's supply of gasoline. Consists of a metal box that contains a flexible, tear-resistant bladder and foam baffling.
Fuel CellsElectro-chemical devices (similar to batteries) that use a continuous supply of hydrogen to produce electricity.
Fuel cycleThe series of steps required to produce electricity. The fuel cycle includes mining or otherwise acquiring the raw fuel source, processing and cleaning…
Fuel EfficiencyThe ratio of heat produced by a fuel for doing work to the available heat in the fuel.
Fuel handling systemA system for unloading wood fuel from vans or trucks, transporting the fuel to a storage pile or bin, and conveying the fuel from storage to the boiler or…
Fuel OilAny liquid petroleum product burned for the generation of heat in a furnace or firebox, or for the generation of power in an engine.
Fuel RateThe amount of fuel necessary to generate one kilowatt-hour of electricity.
Fuel-adjustment clauseA provision of a power sales agreement or rate schedule that allows for the electricity price to be changed based on changes in the price of the fuel used…
Fuel-cell furnaceA variation of the Dutch oven design, that usually incorporates a primary and secondary combustion chamber (cell).
Fugitive DustThe dust released from any source other than a definable point source such as stack, chimney, or vent.
Fujita ScaleThe official classification system for tornado damage. The scale ranges from F0 (gale tornado, minor damage, winds up to 72 mph) to F5 (devastating…
Full SunThe amount of power density in sunlight received at the earth's surface at noon on a clear day (about 1,000 Watts/square meter).
Full-time equivalent (FTE)Equivalent to a full-time worker/employee. For example, two people, each working half time, constitute one FTE.
FungiPlant-like organisms with cells with distinct nuclei surrounded by nuclear membranes, incapable of photosynthesis.
FurbearerAn animal that is hunted or farmed for its fur.
furfuralAn aldehyde derivative of certain biomass conversion processes; used as a solvent.
FurlingThe process of forcing, either manually or automatically, a wind turbine's blades out of the direction of the wind in order to stop the blades from…
FurnaceAn enclosed chamber or container used to burn biomass in a controlled manner to produce heat for space or process heating.
Furnace (Residential)A combustion heating appliance in which heat is captured from the burning of a fuel for distribution, comprised mainly of a combustion chamber and heat…
FuseA safety device consisting of a short length of relatively fine wire, mounted in a holder or contained in a cartridge and connected as part of an…
Futures marketA market in which contracts for future delivery of a commodity or a security are bought and sold.