NWCG Glossary of Wildland Fire, PMS 205

Device which uses the exhaust gas flow of an engine for priming a centrifugal pump.

Water that contains a thickening agent to reduce surface runoff; tends to cling to burning fuels and spread in layers that are several times thicker than plain water, thereby having an increased capacity to absorb heat, cool fuel, and exclude oxygen.

Increasing coupling used on hose, pump, or nozzles to permit connection of a larger size of hose.

That equipment and clothing required to mitigate the risk of injury from or exposure to hazardous conditions encountered during the performance of duty. PPE includes but is not limited to: fire resistant clothing, hard hat, flight helmets, shroud, goggles, gloves, respirators, hearing protection, chainsaw chaps, and shelter. 

An axle that supports a portion of the vehicle weight and transmits a driving force to the wheels.

The specific dimensions of screw thread employed to coupled fire hose and equipment. American National Standards (NH) have been adopted for fire hose couplings threads in 3/4, 1-1/2, 2-1/2, 3-1/2, 4, 5, and 6-inch sizes.

The measure of water flow in firefighting. It is used to measure the output of wildland and structural fire engines, pumps, hose streams, nozzles, hydrants, and water mains.

The process of agitating foam solution and air within a confined space (usually a hose) that produces tiny, uniform bubbles - the length and type of hose determine the amount of scrubbing and, therefore, foam quality.

Retardant drop made from one compartment at a time from an airtanker with a multi-compartment tank.

A combination chopping and trenching tool widely used in fireline construction, which combines a single-bitted axe blade with a narrow adze-like trenching blade fitted to a straight handle.

The apparatus and techniques used to mix concentrate with water to make solution, pump and mix air and solution to make foam, and transport and apply foam. (Systems defined here include compressed air foam and nozzle aspirated.)

A nozzle is designed to provide either a solid stream or a fixed spray pattern suitable for applying water, wet water or foam solution.

Permanent devices with fire engine threads attached to expedite drafting operations in locations where there are water sources suitable for use in fire suppression (e.g., piers, wharves, bridges over streams, highways adjacent to ponds).

A frame on which hose is wound, now chiefly used for "booster" or small hose (3/4- or l-inch hose) (19 or 25 mm) supplied by a water tank on the apparatus; also, a hand-drawn 2-wheel frame for 2-1/2 inch (64 mm) hose used in industrial plants.

Manually adding and mixing a concentrated chemical, such as liquid foam, or powdered or liquid retardant with water, or gelling agents with fuel, into solution in a tank or container.

A pressure-controlled device which bypasses water at a fire pump to prevent excessive pressures when a nozzle is shut down.

A colored flare designed as a railway warning device, widely used to ignite backfires and other prescribed fires.

To drop retardant in such a way that the load slightly overlaps and links a previous drop. "Extend your last drop."

A valve with a gate-like disk that moves up and down at right angles to the flow when actuated by a stem screw and hand wheel. Gate valves are best for service that requires infrequent valve operation and where the disk is kept either fully open or closed. 

A pump which moves a specified quantity of water through the pump chamber with each stroke or cycle; it is capable of pumping air, and therefore is self-priming, but must have pressure relief provisions if plumbing or hoses have shut-off nozzles or valves . Gear pumps and piston pumps are common examples of this type. 

Device for cleaning the exterior of fire hose.

The aerated solution created by forcing air into, or entraining air in water containing a foam concentrate by means of suitably designed equipment or by cascading it through the air at a high velocity. Foam reduces combustion by cooling, moistening and excluding oxygen. 

A chemical that when added to water reduces the surface tension of the solution and causes it to spread and penetrate exposed objects more effectively than the untreated water.

An agent that extinguishes the flaming and glowing phases of combustion by direct application to the burning fuel.

Hose coupling in which the lugs used for tightening or loosening are semicircular in shape and designed to pass over obstructions.

A supply of fire tools and equipment assembled in planned quantities or standard units at a strategic point for exclusive use in wildland operations.

A heavy cutting tool designed primarily to cut brush at the base of the stem. Used in much the same way as an axe and having a wide blade, generally curved to protect the blade from being dulled by rocks.

A device used to introduce and mix fire chemical into a water stream. An eductor is a fitting with three ports, an inlet for water flow, an outlet for water flow, and an inlet for fire chemical concentrate. The flow of water through the eductor produces a region of lower pressure at the fire chemical inlet, drawing the chemical into the water stream. 

Result of chemical reaction between a metal and its environment (i.e., air, water, and impurities in same).

A low expansion foam type with few and varied bubbles and rapid drain time which is used for rapid penetration and fire extinguishment.

A hose lay consisting of consecutively coupled lengths of hose without laterals. The lay is extended by inserting additional lengths of hose in the line between pumps and nozzle.

A resource that includes a dozer, its transportation unit and a standard complement of personnel for its operation.

The time (minutes) it takes for foam solution to drop out from the foam mass; for a specified percent of the total solution contained in the foam to revert to liquid and drain out of the bubble structure.

Removal of the first (i.e., outside) thread of a female or male coupling to prevent crossing or mutilation of threads. Dimpled rocker lug on female coupling indicates beginning of Higbee Cut.

A surface active agent; any wetting agent. A formulation which, when added to water in proper amounts, will materially reduce the surface tension of the water and increase penetration and spreading abilities of the water.

Use of two or more fire pumps to move water a distance which would require excessive pressures in order to overcome friction loss if only one pump were employed at the source.

A secondary pump on an engine in addition to the main pump. Usually of small capacity.

Any agent used to extinguish the flaming and glowing phases of combustion by direct application to the burning fuel.

External diameter of a cylinder or tube, conductor, or coupling as distinguished from the internal diameter.

Blade attachment with long teeth specially suited to ripping and piling brush with minimum inclusion of soil.

Unit of fluid viscosity in fire retardant, defined as tangential force per unit area (dynes/square centimeter) required to maintain unit difference in velocity (1 centimeter/second) between two parallel planes separated by 1 cm of fluid (1 poise=1 dyne-second/cubic centimeter). 

A hose lay in which double shutoff wye (Y) valves are inserted in the main line at intervals and lateral lines are run from the wyes to the fire edge, thus permitting continuous application of water during extension of the lay.

The building block of foam; bubble characteristics of water content and durability influence foam performance.

The internal diameter of a tube, conductor, or coupling, as distinguished from its OD (Outside Diameter). Fire hose sizes are classified by a nominal internal diameter.

Commonly accepted term for short length of large diameter soft hose used to connect a structural or wildland engine with a hydrant. No vacuum is involved because the hose is useful only when the engine receives water at a rate of flow in excess of the demand of the pump. 

Fire hose coupling with American National Standard (NH) threads.

Weight of a truck empty (without payload and driver) but ready to drive, including a full fuel tank, cooling system, crankcase, tools, spare wheel, and all other equipment specified as standard.

Method of carrying hose on the shoulders.

Foam intended for use on Class A or woody fuels; made from hydrocarbon-based surfactant, therefore lacking the strong filming properties of Class B foam, but possessing excellent wetting properties.

Any steel tracked vehicle equipped with a front mounted blade used for exposing mineral soil.