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Airtanker—Fixed-wing aircraft certified by the Federal Aviation Administration as being capable of transporting and delivering fire retardant solutions.

Anchor Point—An advantageous location, usually a barrier to fire spread, to start constructing a fireline. The anchor point is used to minimize the chance of being flanked by the fire while the line is being constructed.

Baffling—Partitions placed in tanks to reduce shifting of the water load and to give the tank greater structural integrity.

Bambi bucket—A collapsible helibucket slung below a helicopter, typically used to dip water from a variety of water sources for fire suppression.

Bentonite—A clay slurry, short-term fire retardant whose effectiveness depends primarily on the water it holds.

Breakup—The dispersion of retardant, foam, or water in the air after it is released from a tank or bucket.

Borate—One of the first long-term fire retardants. Its use was discontinued in the 1960’s.

Constant-flow airtankers—Airtankers that use doors to control the flow rate.

Contour plots—A graphical picture on which the characteristics of a surface are shown by contour lines. In drop testing, the contour line is a line that joins points of equal coverage level on a surface.

Conventional airtankers—Airtankers that divide the retardant load into isolated compartments. The release system is designed to open the doors of these compartments in sequence, producing a line of retardant.

Correlated—When two or more things are mutually related. In statistics, correlation refers to interdependence between two or more variables.

Coverage level—A recommended amount of retardant (in gallons) applied to a specific area (100 square feet) of surface. Coverage level 2 represents 2 gallons of retardant per hundred square feet of surface.

Cup-and-grid method—A procedure incorporating containers set in a regular, defined pattern to measure deposition patterns created by the aerial release of fire-retarding chemicals.

Direct attack—Any treatment applied directly to burning fuel to stop combustion.

Drift—The effect of wind on retardant or suppressant drops.

Drop test—A test of a fire chemical delivery system flying over a cup-and-grid matrix to determine the coverage level producted for each drop type.

Fire retardant—Any substance, except plain water, that by chemical or physical action reduces the flammability of fuels or slows their rate of combustion.

Fire suppressant—An agent that is directly applied to burning fuel to extinguish the flaming and glowing phases of combustion.

Flight path—Track of an aircraft over the earth’s surface.

Flow rate—The rate at which the retardant exits a tank or bucket, usually expressed in gallons per second.

Foam—The aerated bubble structure created by forcing air into a water solution containing a foam concentrate. Foam may be produced by suitably designed equipment or by cascading a water solution containing a foam solution at high velocity through the air.

Gate—Refers to the door area and release mechanism of a tank.

Gelgard F—A firefighting gel. Gels modify the physical properties of water, especially its ability to cling to fuel. Gels rely on the moisture they contain to reduce or inhibit combustion.

Ground pattern—The characteristics of a ground pattern of fire-retarding chemicals, including length, width, area, and coverage level expressed in gallons per hundred square feet.

Gum-thickened retardant—Any fire-fighting product containing a thickener. The thickener increases the product’s elasticity.

Helicopter buckets—A container suspended below a helicopter, usually used for dipping water for firefighting.

Helitanker—A helicopter equipped with a fixed-tank or a bucket-type container that is used for aerial delivery of water or retardants.

Line building—Constructing a fireline. Aircraft drop retardant or suppressant in overlapping lines to help ground crews build fireline.

Line length—The length, usually expressed in feet, of a ground pattern. Line length is used to relate the length of different coverage levels within a ground pattern.

Linear interpolation—Estimation of a value of a variable between two known values that assumes uniform change between the two known values.

Recovery rates—The estimated amount of retardant recovered from the cup and grid method compared to the amount of retardant dropped, expressed as a percentage of total gallons dropped.

Retardant—see fire retardant.

Retardant mass—The total volume of retardant released from the aircraft.

Rheological properties—Those properties, including viscosity and elasticity, affecting the flow characteristics of a fluid. These properties affect the behavior of the retardant as it is dropped from an airtanker.

Short-term fire retardant—A formulation added to water to modify its physical properties, improving its drop characteristics or its ability to cling to fuel. The retardant relies on the moisture it contains to reduce or inhibit combustion. It is ineffective once its moisture has evaporated.

Spatial statistics—Statistical methods for spatial data. Typically, these data fall into three categories: lattice data, geostatistical data, and spatial point patterns.

Tank and gating system—Tank, doors, and release mechanism installed in aircraft to release a drop.

Torque tubes—A hydraulically or pneumatically powered, rotating shaft that opens and closes the tank’s doors.

Tree canopy—The layer containing the crowns of the tallest vegetation present (living or dead), usually above 20 feet.

Understory—Low-growing vegetation under a stand of trees. Also the portion of trees in forest stands below the forest canopy.

Venting—The openings in the tank vents used to allow air into the tank.

Viscosity—A measure of a fluid’s resistance to flow. With foam, an indication of the foam’s ability to spread over and cling to fuels and to itself.

Water-like retardant—Unthickened products or thickened products that do not have elasticity.

Wildland fire—A fire in wildland.

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This page last modified July 30, 2001

Visitor since July 30, 2001