– B –

Back Azimuth
Angle or bearing 180 degrees opposite of azimuth.

Used in some localities to specify fire set to spread against the wind in prescribed burning.

Instantaneous explosion or rapid burning of superheated gases that occurs when oxygen is introduced into an oxygen-depleted confined space. It may occur because of inadequate or improper ventilation procedures.

Backfire Torch
A flame generating device (e.g., a fount containing diesel oil or kerosene and a wick, or a backpack pump serving a flame-jet).
synonym: Burning Torch
see also: Drip Torch
see also: Flame Thrower

A fire set along the inner edge of a fireline to consume the fuel in the path of a wildfire or change the direction of force of the fire’s convection column.
see also: Burn Out

A tactic associated with indirect attack, intentionally setting fire to fuels inside the control line to slow, knock down, or contain a rapidly spreading fire. Backfiring provides a wide defense perimeter and may be further employed to change the force of the convection column. Backfiring makes possible a strategy of locating control lines at places where the fire can be fought on the firefighter’s terms. Except for rare circumstance meeting specified criteria, backfiring is executed on a command decision made through line channels of authority.

Background Level
In air pollution control, the concentration of air pollutants in a definite area during a fixed period of time prior to the starting up, or the stoppage, of a source of emission under control. In toxic substances monitoring, the average presence in the environment, originally referring to naturally-occurring phenomena.

Backing Fire
(1) Fire spreading, or ignited to spread, into (against) the wind or downslope. A fire spreading on level ground in the absence of wind is a backing fire.|
(2) That portion of the fire with slower rates of fire spread and lower intensity normally moving into the wind and/or down slope.
Also called: heel fire.

Backing Wind
Wind that changes direction in a counter clockwise motion.

Backpack Pump
A portable sprayer with hand-pump, fed from a liquid filled container fitted with straps, used mainly in fire and pest control.
see also: Bladder Bag

A partitioned wall placed in vehicular or aircraft water tanks to reduce shifting of the water load when starting, stopping or turning.

Ball Valve
A valve in which fluid flow is controlled by a ball with a hole drilled through it. In one position, fluid flows through the hole. When the valve is turned 90 degrees (1/4 turn) the hole is perpendicular to the flow and the ball stops the flow. Intermediate valve positions can be used to adjust the flow.

Bambi Bucket ®
A collapsible bucket slung below a helicopter. Used to dip water from a variety of sources for fire suppression.

Banking Snags
The act of throwing mineral soil about the base of an unlighted snag to prevent its being ignited by a surface fire.

An instrument for measuring the pressure of the atmosphere. The two principal types are the mercurial and the aneroid.

Barometric Pressure
Atmospheric pressure corrected for elevation.
see also: Atmospheric Pressure

Any obstruction to the spread of fire. Typically an area or strip devoid of combustible fuel.

Base Area
Part of the National Fire Danger Rating System (NFDRS). An area representative of the major fire problems on a protection unit. Base fuel model and slope class are chosen from the base area.

Base Fuel Model
Part of the National Fire Danger Rating System (NFDRS). A representation of the vegetative cover and fuel in a base area. Used in the calculation of fire danger rating.

Base Manager (BCMG)
This ICS position is responsible for ensuring that appropriate sanitation, security, and facilities management services are provided at the Incident Base and reports to the Facilities Unit Leader.
see also: Camp Manager
see also: Facilities Unit

Base Observation Time
Part of the National Fire Danger Rating System (NFDRS). The time established to take the fire danger observations. It should be at the time of day when the fire danger is normally the highest. The usually agreed upon time is 1:00 pm standard time. This allows time to transmit observations and prepare forecasts.

Base Station
A fixed central radio dispatching station controlling movements of one or more mobile units.

(1) The location at which primary logistics functions for an incident are coordinated and administered. There is only one base per incident. (Incident name or other designator will be added to the term “base.”) The incident command post may be collocated with the base.
(2) The location of initial attack forces.
see also: Camp

In prescribed burning, the initial line of fire, usually set as a backing fire along a barrier or control line, which serves to contain subsequent burning operations.

Basic Life Support (BLS)
Basic life support skills performed by an EMS practitioner or service, e.g. splinting, bandaging, oxygen administration, use of the AED.

Batch Mix
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.

The horizontal direction to or from any point, usually measured clockwise from true north, or some other reference point through 360 degrees.

Beaufort Wind Scale
A system of estimating and reporting wind speeds. In its present form for international meteorological use it equates (a) Beaufort force (or Beaufort number), (b) wind speed, (c) descriptive term, and (d) visible effects upon land objects or sea surf.

A system of interactive computer programs for modeling fuel and fire behavior, comprised of two systems: BURN and FUEL.

An observable activity or action demonstrated by an individual in a particular context.
see also: Competency

Belt Weather Kit
Belt-mounted case with pockets fitted for anemometer, compass, sling psychrometer, slide rule, water bottle, pencils, and book of weather report forms. Used to take weather observations to provide on-site conditions to the fire weather forecaster or fire behavior analyst. Observations include air temperature, wind speed and direction, and relative humidity.

A ridge of soil and debris along the outside edge of a fireline, resulting from line construction.
see also: Throw Out

Best Available Control Measures (BACM)
An emission limitation action based on the maximum degree of emission reduction (considering energy, environmental, and economic impacts) achievable through application of production processes and available methods, systems, and techniques.
see also: Reasonably Available Control Measures

Preburning of fuels adjacent to a control line before igniting a prescribed burn. Blacklining is usually done in heavy fuels adjacent to a control line during periods of low fire danger to reduce heat on holding crews and lessen chances for spotting across control line. In fire suppression, a blackline denotes a condition where there is no unburned material between the fireline and the fire edge.

Bladder Bag
A collapsible backpack portable sprayer made of neoprene or high-strength nylon fabric fitted with a pump.
see also: Backpack Pump

Blind Area
An area in which neither the ground nor its vegetation can be seen from a given observation point.

Block Plan
A detailed prescription for treating a specified burning block with fire.
see also: Burning Block

Blow Down
An area of previously standing timber which has been blown over by strong winds or storms.

Sudden increase in fireline intensity or rate of spread of a fire sufficient to preclude direct control or to upset existing suppression plans. Often accompanied by violent convection and may have other characteristics of a fire storm.
see also: Extreme Fire Behavior
see also: Fire Storm
see also: Flare-up

Board of Review
A board or committee selected to review results of fire suppression action on a given unit or the specific action taken on a given fire. The board reviews the results in order to identify reasons for both good and poor action and to recommend or prescribe ways and means of doing an effective and efficient job. Reviews the results of a safety/accident investigation.

Boiling Liquid Expanding Vapor Explosion (BLEVE)
(1) The failure of a closed container as a result of overpressurization caused by an external heat source.
(2) A major failure of a closed liquid container into two or more pieces when the temperature of the liquid is well above its boiling point at normal atmospheric pressure.

The trunk of a tree.

Bone Yard
(1) A mop up term. To “bone yard” a fire means to systematically work the entire area, scraping embers off remaining fuel, feeling for heat with the hands, and piling unburned materials in areas cleared to mineral soil.
(2) An area cleared to mineral soil for piling unburned fuels.

Booster Hose
The most common type of hose attached and stored on wildland engine booster reels. The hose is made of neoprene and does not appreciably collapse when stored empty.

Booster Pump
An intermediary pump for supplying additional lift in pumping water uphill past the capacity of the first pump.

Booster Reel
A reel for the booster hose mounted on a fire engine, often supplied by the auxiliary pump. This reel usually carries a 1-inch (25 mm) or 3/4 inch (19 mm) hose and frequently contains an electric rewind mechanism.
see also: Hose Reel

Boundary Conditions
The temperature and relative humidity of the boundary layer.

Boundary Layer
(1) The air in immediate contact with a fuel particle.
(2) That part of the lower atmosphere that is directly influenced by the presence of the earth’s surface and responds to surface forcings with a time scale of about an hour or less.

Boundary Value
The equilibrium moisture content (EMC) commensurate with the boundary conditions and precipitation events of the preceding 24 hours.

Bowles Bag
A neoprene tank designed for attachment to the landing skid frame of a helicopter. It has a capacity of 80 to 100 gallons (303 to 378 liters) of water or retardant.

Box Canyon
A steep-sided, dead end canyon.

The organizational level having functional or geographical responsibility for major parts of incident operations. The branch level is organizationally between section and division/group in the operations section, and between section and unit in the logistics section. Branches are identified by roman numerals or by functional name (e.g. service, support).

Break a Line
To insert a gate valve or some other device into a hose line.

Break Coupling
To detach two pieces of hose by backing the swivel thread off the nipple thread.

Break Left or Right
Means “turn” left or right. Applies to aircraft in flight, usually on the drop run, and when given as a command to the pilot, implies expectation of prompt compliance.

A fire edge that crosses a control line or natural barrier intended to confine the fire.
synonym: Slopover

British Thermal Unit (Btu)
Amount of heat required to raise 1 pound of water 1 degree Fahrenheit (from 59.50 to 60.50 F), measured at standard atmospheric pressure.

Broadcast Burning
Prescribed burning activity where fire is applied generally to most or all of an area within well defined boundaries for reduction of fuel hazard, as a resource management treatment, or both.

Brown and Burn
Application of herbicide to desiccate living vegetation prior to burning.

Brownspot Control
Prescribed fire to control fungal infection (brown spot disease) of longleaf pine (Pinus palustris) in the “grass” (small seedling) stage.

Brush Blade
Blade attachment with long teeth specially suited to ripping and piling brush with minimum inclusion of soil. Also called brush rake or root rake.

Brush Fire
A fire burning in vegetation that is predominantly shrubs, brush, and scrub growth.

Brush Hook
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.

Brush Management
Manipulation of stands of brush by manual, mechanical, chemical, or biological means or by prescribed burning for the purpose of achieving land management objectives.

Brush Patrol Unit
Any light, mobile vehicular unit with limited pumping and water capacity for off-road operations.

A collective term that refers to stands of vegetation dominated by shrubby, woody plants, or low growing trees, usually of a type undesirable for livestock or timber management.

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

Bucket Drops
The dropping of fire retardants or suppressants from specially designed buckets slung below a helicopter.

Sawing through the bole of a tree after it has been felled.

Buildup Index (BUI)
A relative measure of the cumulative effect of daily drying factors and precipitation on fuels with a ten-day timelag.

(1) The cumulative effects of long-term drying on current fire danger.
(2) The increase in strength of a fire management organization.
(3) The accelerated spreading of a fire with time.
(4) Towering cumulus clouds which may lead to thunderstorms later in the day.

Bulk Density
Weight per unit volume. For fuels, this is usually expressed as pounds per cubic foot; for soils, grams per cubic centimeter.
see also: Compactness

Bumpup Method
Progressive method of fireline construction on a wildfire without changing relative positions in the line. Work is begun with a suitable space between workers; whenever one worker overtakes another, all of those ahead move one space forward and resume work on the uncompleted part of the line. The last worker does not move ahead until work is completed in his/her space. Forward progress of the crew is coordinated by a crew boss.
synonym: Moveup Method

Burn Block
A discrete area within a larger prescribed or fire use project.

Burn Boss
Person responsible for supervising a prescribed fire from ignition through mopup.

Burn Out Time
The duration of flaming and smoldering combustion phases at a specified point within a burn or for the whole burn, expressed in convenient units of time.

Burn Out
Setting fire inside a control line to consume fuel between the edge of the fire and the control line.
see also: Backfire

Burn Patterns
(1) The characteristic configuration of char left by a fire. In wildland fires burn patterns are influenced by topography, wind direction, length of exposure, and type of fuel. Definitions are scale-dependent: (a) They can be used to trace a fire’s origin; (b) They are influenced by severity and intensity within a stand; (c) They describe the landscape mosaic.
(2) Apparent and obvious design of burned material and the burning path from the area of origin.

Burn Severity
A qualitative assessment of the heat pulse directed toward the ground during a fire. Burn severity relates to soil heating, large fuel and duff consumption, consumption of the litter and organic layer beneath trees and isolated shrubs, and mortality of buried plant parts.

(1) An area burned over by wildland fire.
(2) A reference to a working fire.
(3) An injury to flesh caused by a cauterizing agent, heat from a fire, or a heated object a) First Degree Burn: A burn which causes only pain, redness, and swelling. b) Second Degree Burn: A burn in which the skin is blistered. c) Third Degree Burn: A flesh burn in which charring occurs.
(4) To be on fire.
(5) To consume fuel during rapid combustion. A fire in progress or under investigation.

Burning Ban
A declared ban on open air burning within a specified area, usually due to sustained high fire danger.

Burning Conditions
The state of the combined factors of the environment that affect fire behavior in a specified fuel type.

Burning Index Meter
A device used to determine the burning index for different combinations of burning index factors.

Burning Index
An estimate of the potential difficulty of fire containment as it relates to the flame length at the head of the fire. A relative number related to the contribution that fire behavior makes to the amount or effort needed to contain a fire in a specified fuel type. Doubling the burning index indicates that twice the effort will be required to contain a fire in that fuel type as was previously required, providing all other parameters are held constant.

Burning Out
Setting fire inside a control line to consume fuel located between the edge of the fire and the control line.

Burning Period
That part of each 24-hour period when fires spread most rapidly; typically from 10:00 AM to sundown.

Burning Priority Rating
System of rating slash to indicate the treatment objective, whether or not burning is required to meet that objective, the fuel treatment necessary to achieve successful burning, and the time of year burning should occur.

Burning Rate
Rate at which a propellant and other combustibles burn.

Burning Rotation
The planned number of years between prescribed fires on a specified area.

Burning Torch
A flame generating device (e.g., a fount containing diesel oil or kerosene and a wick, or a backpack pump serving a flame-jet).
synonym: Backfire Torch
see also: Drip Torch
see also: Flame Thrower

Decomposition of material by the application of heat and oxidation. Also applied to propellants and other pyrotechnic mixtures, though the proper term there is “reacting”. Also often an element of the crime of arson.

An event in which a fire moves through a location or overtakes personnel or equipment where there is no opportunity to utilize escape routes and safety zones, often resulting in personal injury or equipment damage.

Buying Team
A team that supports incident procurement through the local administrative staff and is authorized to procure a wide range of services, supplies, and land and equipmental rentals. In addition, the Buying Team Leader has the responsibility of coordinating property accountability with the supply unit leader.

Buys Ballot’s Law
If a person stands with his back to the general wind, the high atmospheric pressure is found to his right in the Northern Hemisphere. The high pressure on the right moves clockwise and outward from the cell. The low pressure on the left moves counterclockwise and towards the center of the cell. This Law does not work in the presence of locally produced convective winds.

Source: National Wildfire Coordinating Group