B

B - end 

End of the tank car on which the handbrake is located. If the car has two handbrakes, the "B" end is the end toward which the body-mounted brake cylinder piston moves when brakes are applied.

Back flushing

The cleaning of a fire pump or piping by flowing water through it in the opposite direction of normal flow.

Back pack

A tank-type extinguisher carried on the back of the firefighters with straps to hold it in place and a pump built into the nozzle. Used extensively in natural cover fire fighting. Also, a pack used to carry hose on firefighters' backs.

Back pack pump

A tank-type extinguisher carried on the back of a firefighter and used primarily in natural cover firefighting.

Back pressure 

A pressure loss or gain created by changes in elevation between the nozzle and pump. The pressure created by gravity at the base of a column of water. See Head Pressure.

Backdraft 

 An explosion or rapid burning of heated gases in a confined structure. A backdraft may occur because of inadequate or improper ventilation procedures. A backdraft occurs when an oxygen-starved fire suddenly receives oxygen. The sudden rush of oxygen causes all of the super-heated gases to ignite at the same time, which causes an explosion. The force of the backdraft depends on variables like the size of the confined area, the extent to which smoldering has occurred (thus providing fuel), the degree of heating of the atmosphere, and the rate at which air or oxygen is introduced. While the risk of such an occurrence is low, a backdraft is almost always fatal to anyone caught in it. Also known as a smoke explosion. Warning signs of possible backdraft include little or no visible flame, black smoke becoming dense gray yellow, smoke stained windows, and smoke escaping in intervals, or a puffing effect.

Backflow preventer

A device or means that prevents the backflow of a liquid into the potable water supply.

Backing

Frame lumber installed between the wall studs to give additional support for drywall or an interior trim related item, such as handrail brackets, cabinets, and towel bars. In this way, items are screwed and mounted into solid wood rather than weak drywall that may allow the item to break loose from the wall. Carpet backing holds the pile fabric in place.

Bacteria

Single-celled organisms that multiply by cell division and that can cause disease in humans, plants or animals.

Bacterial penetration

The infiltration of bacteria through protective clothing materials.

Bactericide

A pesticide used to control bacteria

Bacteriophage

A type of virus that infects bacteria.

Baffles

 A wall or screen for controlling the flow of air, water, etc., by hindering its movement or changing its course. An intermediate partial bulkhead that reduces the surge effect in a partially loaded tank. Baffles are perforated dividers placed in fire department water tanks to prevent the rapid shifting of water loads while the apparatus is in motion. Baffles are also used to divide beds of hose into two or more compartments.

Bale hooks

A hook shaped tool for moving bales or other items, and for overhauling stuffed furniture. Also known as a hay hook.

Ball valve

Valve having a ball-shaped internal component with a hole through its center that permits water to flow through when aligned with the waterway.

Ballast

A transformer that steps up the voltage in a florescent lamp.

Balloon frame 

A building with studs running two or more stories without fire stops. This is a type of construction that typically used lath and plaster wall hung on the studs. The open spaces between studs extended from foundation to the attic. The opening, with exposed wood lath allow fire to travel unimpeded with easily ignitable wood fibers exposed. Framed walls (generally over 10' tall) that run the entire vertical length from the floor sill plate to the roof. This is done to eliminate the need for a gable end truss.

Balloon throw

A salvage cover throw that traps air beneath the cover to assist in spreading by ballooning the cover over the material to be covered.

Balusters

Vertical members in a railing used between a top rail and bottom rail or the stair treads. Sometimes referred to as 'pickets' or 'spindles'.

Balustrade

The rail, posts and vertical balusters along the edge of a stairway or elevated walkway.

Bangor ladder

A very large extension ladder that requires tormentor poles to steady the ladder as it is raised and lowered; usually 40 to 50 feet. Also known as a pole ladder.

Barge

Horizontal beam rafter that supports shorter rafters.

Barge board

A decorative board covering the projecting rafter (fly rafter) of the gable end. At the cornice, this member is a fascia board.

Barometric pressure

The pressure at a given temperature and altitude due to the pressure of the atmosphere.

Barrier 

In protective clothing, barrier is the ability to isolate the body from a chemical, physical, biological, radioactive or thermal hazard, among others.

Base (chemical)

A hydroxide-containing corrosive material that, when in a water solution, is bitter, more or less irritating or caustic to the skin. A chemical compound that reacts with an acid to form a salt. The term is applied to the hydroxides of the metals, to certain metallic oxides, and to groups of atoms containing one or more hydroxyl groups (OH-) in which hydrogen is replaceable by an acid radical. Sodium hydroxide is an example of a base. See Alkaline.

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Base (NIMS / ICS)

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.

Base or baseboard 

A trim board placed against the wall around the room next to the floor.

Base shoe

 Molding used next to the floor on interior base board. Sometimes called a carpet strip.

Basement window inserts

The window frame and glass unit that is installed in the window buck.

Basic Life Support

Basic life support (BLS) is a level of care provided to patients requiring transportation to the hospital. BLS does not include extensive medical supervision or treatment.

Bat

A half-brick.

Batt 

A section of fiber-glass or rock-wool insulation measuring 15 or 23 inches wide by four to eight feet long and various thickness'.  Sometimes "faced" (meaning to have a paper covering on one side) or "unfaced" (without paper).

Battalion

A fire department subdivision consisting of all fire service equipment and personnel in a designated geographic area, usually two or more companies. The battalion chief is one the senior officers within the management hierarchy. The battalion chief commands the fire personnel on a shift and carries other comparable responsibilities in the fire department, which require the attention of a chief officer. The battalion chief wears white turnouts and helmet for identification. He is usually the first arriving officer that assumes command of an incident requiring the use of more than one company

Batten

Narrow strips of wood used to cover joints or as decorative vertical members over plywood or wide boards.

Bay window

Any window space projecting outward from the walls of a building, either square or polygonal in plan.

Bead

A round globule of resolidified metal at the end of the remains of an electrical conductor that was caused by arcing.

Beam (ladder)

The main structural member of a ladder supporting the rungs or rung blocks.

Beam (construction)

A structural member transversely supporting a load. A structural member carrying building loads (weight) from one support to another. Sometimes called a "girder".

Beam raise

Raising a ladder to a vertical position by either beam instead of in a flat horizontal plane.

Bearing header

(a) A beam placed perpendicular to joists and to which joists are nailed in framing for a chimney, stairway, or other opening. (b) A wood lintel. (c) The horizontal structural member over an opening (for example over a door or window).

Bearing partition

A partition that supports any vertical load in addition to its own weight.

Bearing point

 A point where a bearing or structural weight is concentrated and transferred to the foundation

Bearing wall

A wall that supports a vertical load, such as a floor or roof, in addition to its own weight.

Bed ladder

The lowest section of a multi-section ladder.

Bed ladder pipe

A telescoping section of pipe, usually 3 or 3 1/2 inches in diameter, attached to the underside of the bed section of the aerial ladder for the purpose of deploying an elevated master stream.

Belly valve

Any type of tank valving located on the bottom of the tank.

Beta rays

Smaller than alpha rays, beta radiation is made up of electrons.

Bifold door 

Doors that are hinged in the middle for opening in a smaller area than standard swing doors. Often used for closet doors.

Big line

Large diameter fire hose used to connect a hydrant to a fire engine for water supply. Big line dimensions can be 2 ½”, 4”, 5" or 6".

Big stick 

A mechanically-raised main ladder on an aerial ladder truck. Originally aerial ladders were made of wood, and hence the term “big stick.”

Bill of lading

A shipping paper for transportation by highway. This paper is typically the bill of sale and can give very valuable information about the exact weights and contents of containers and the shipper and consignee of the shipments.

Biochemicals

The chemicals that make up or are produced by living things.

Biohazard

Infectious agents presenting a risk or potential risk to living organisms, either directly through infection or indirectly through disruption of the environment. Those organisms that have a pathogenic effect on life and the environment and can exist in normal ambient environments. These hazards can represent themselves as disease germs, and viruses.

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Biohazard warning sign

A sign used as an administrative exposure control practice for alerting personnel who may enter an area where biohazards are present so that they may take precautionary exposure control measures. Traffic in such areas can be restricted by posting such signs where they can be easily seen. These signs should only be used for the purpose of signifying the actual or potential presence of biohazards.

Bypass doors       

Doors that slide by each other and commonly used as closet doors.

Blackout

As the flame is extinguished, the fire is said to be blacked out. To “knock down” a fire; to reduce a fire by extin­guishing all visible flame. (Also called blacken or darkening down.) See knock down.

Blankets 

Fiber-glass or rock-wool insulation that comes in long rolls 15 or 23 inches wide.

Blast area

The area affected by the blast wave from an explosion.

Bleeder valve 

Valve on a gate intake that allows air from an incoming supply line to be bled off before allowing the water into the pump.

BLEVE

Acronym for Boiling Liquid Expanding Vapor Explosion. Pronounced blevy. This is a type of explosion that can occur when a vessel containing a pressurized liquid is ruptured. Such explosions can be extremely hazardous. A BLEVE can occur in a vessel that stores a substance that is usually a gas at atmospheric pressure but is a liquid when pressurized (for example, liquified petroleum gas). The substance will be stored partly in liquid form, with a gaseous vapor above the liquid filling the remainder of the container. If the vessel is ruptured the vapor portion may rapidly leak, dropping the pressure inside the container. This explosion is assisted with the weakening of the vessel wall due to direct flame impingement or extreme radiant heat that causes the liquid to boil and produce more vapors. The pressure of this vapor can be extremely high causing an explosion which may completely destroy the storage vessel and project it as shrapnel over the surrounding area. Railcars and pieces of railcars have been thrown up to a mile away from the explosion.

Blitz attack

A rapid and massive attack on a fire to knock down a fire before it has a chance to grow into a larger fire.

Block and tackle

The rope and pulley assembly used to obtain a mechanical advantage for hoisting or pulling.

Block out

To install a box or barrier within a foundation wall to prevent the concrete from entering an area. For example, foundation walls are sometimes "blocked" in order for mechanical pipes to pass through the wall, to install a crawl space door, and to depress the concrete at a garage door location.

Blocked (door blocking)

Wood shims used between the door frame and the vertical structural wall framing members.

Blocked (rafters)

Short "2 by 4's" used to keep rafters from twisting, and installed at the ends and at mid-span.

Blocking

Small wood pieces to brace framing members or to provide a nailing base for gypsum board or paneling.

Blood bourne pathogen

A pathogenic microorganism that is present in human blood and can cause disease in humans. OSHA 29CFRI910.1030 is the regulation covering the protection of workers from blood-borne pathogens.

Blow insulation

Fiber insulation in loose form and used to insulate attics and existing walls where framing members are not exposed.

Board foot 

A unit of measure for lumber equal to 1 inch thick by 12 inches wide by 12 inches long. Examples: 1" x 12" x 16' = 16 board feet, 2" x 12" x 16' = 32 board feet

Body fluid 

Any liquid produced, secreted or excreted by the human body

Boiler

A steam-generating unit used for heating as well as other auxiliary purposes.

Boiling point

The temperature at which the vapor pressure of a liquid equals the atmospheric pressure. The boiling point is an indicator of the vapor pressure of a substance. A liquid with a low boiling point (less than 100 degree F  has a higher vapor pressure. The temperature at which the transition from the liquid to the gaseous phase occurs. At this temperature, vapor pressure of a liquid now equals the surrounding atmospheric pressure so that the liquid rapidly becomes a vapor. Flammable materials with low BPs generally present special fire hazards.

Boilover 

The overflow of crude oil from its container when the heat wave reaches the water level in the tank. The water flashes to steam causing a violent expulsion of the material as a froth.

Bolt cutters

A cutting tool designed to make a precise, controlled cut. Used for cutting wire, fencing, bolts, and small steel bars.

Booby trap

A bomb or chemical arrangement designed to explode or react when an object is pushed, moved, or grasped. Booby traps are commonly found in clandestine drug labs to eliminate evidence of illicit activity or to injure any person that is not associated with the illegal lab.

Boom (construction)

A truck used to hoist heavy material up and into place. To put trusses on a home or to set a heavy beam into place.

Boom (dyking)

To confine, extend, move, or manipulate (by means of logs or the like) a body of water.

Booming

The process of containing a spilled material on waterways, especially those that float on the surface of water, such as oil.

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Booster hose or line

A reinforced, rubber-covered, rubber-lined fabric hose. Booster hose is generally carried on apparatus on a mounted reel and is used for extinguishing small incipient and smoldering fires. Due to small diameter being less than one inch, the gallons per minute is relative low at 30 to 50 GPM. Therefore it is not a good choice for structural or vehicular fires. Booster lines do not need to be disconnected and rolled after each use because they are rolled directly back onto the reel. Typically used for very small fires such as brush, trash, grass, tree, and mulch fires. Many fire departments having to conserve available space for other equipment have eliminated the booster line in favor of fabric line (called forestry line) or relied upon structural attack sized lines. Also referred to as a red line.

Booster pump      

A pump with less than 500 gallons per minute rating; usually an auxiliary to other pumps on fire apparatus. Used to supply water through booster hose. Fire pump used to boost the pressure of the existing water supply within a fixed fire protection system.

Booster reel

A mounted reel on which booster hose is carried.

Booster Tank

The tank on a pumper or quint that supplies booster lines and hand lines at a fire until a connection with a water source can be made. The booster tank on most pumpers is between 500-1,000 gallons.  The tank on a quint is usually smaller, carrying only a couple of hundred gallons.

Boots

Specially designed firefighter's rubber boots are required, to complete a set of protective clothing, or bunker gear.

Bottom chord

The lower or bottom horizontal member of a truss.

Bottom plate

The 2 by 4's or 6's that lay on the subfloor upon which the vertical studs are installed. Also called the 'sole plate'.

Bourdon Tube

A thin, curved, hollow, pressure-sensitive tube found in pressure gauges to operate the needle of the gauge. Part of a pressure gauge that has a curved, flat tube that changes its curvature as pressure changes. This movement is then transferred mechanically to a pointer on the dial.

Box

A short term for public or private fire alarm box. The fire alarm box often seen on street corners and in hallways of schools and commercial buildings. Usually given a location number, this number can be used by engine companies to determine exact locations when responding to a fire.

Box Alarm

A box alarm is the response to a report of fire or smoke inside or coming from a structure. Usually, multiple companies are dispatched at the same time on a box alarm. Some departments have Haz-Mat and Rescue Boxes for hazardous materials and rescue calls. The term box alarm originates from the original pull boxes located on the street in many communities. A typical structure box alarm would include two or more engine companies, one or more ladder companies, a rescue company and a chief officer.

Boyle's Law

Boyle’s Law states that the pressure of a gas is inversely proportional to its volume at a given temperature. The law relates to the compressibility of gas and the effect of temperature and volume on the pressure in a pressurized container.

Brace

An inclined piece of framing lumber applied to wall or floor to strengthen the structure. Often used on walls as temporary bracing until framing has been completed.

Brake hose

A flexible conductor for the transmission of fluid pressure in the brake system.

Braking distance

Distance the vehicle travels from the time the brakes are applied until it comes to a complete stop.

Branch

 The organizational level having functional or geographic responsibility for major parts of the Operations or Logistics functions. The Branch level is organizationally between Section and Division/Group in the Operations Section, and between Section and Units in the Logistics Section. Branches are identified by the use of Roman Numerals or by functional name (e.g., medical, security, etc.).

Brass

Brass work or brass appliances carried on fire apparatus. Now may be chrome plated or made of lightweight alloys.

Breach

An opening made in a wall for rescue, hose line operation, or other reasons.

Break a line

To disconnect hose lines for any purpose, especially to break and roll up hose after a fire operation; to disconnect a hose coupling.

Breaker panel            

The electrical box that distributes electric power entering the home to each branch circuit (each plug and switch) and composed of circuit breakers.

Breakover angle

Angle formed by level ground and a line from the point where the rear tires of a vehicle touch the ground to the bottom of the frame at the wheelbase midpoint.

Breathing air

Air that equals or exceeds Grade D specifications for gaseous air in accordance with CGA G-7.1 -89, and that does not present a health hazard to anyone breathing the air. Compressed air for SCBA is graded to this standard.

Breathing equipment

Normally used to describe self-contained breathing equipment (SCBA) consisting of an air or oxygen tank, connecting hoses, regulator, and face piece.

Brick joisted

Brick or masonry wall structure with wooden floors and roof joists. Commonly known as ordinary construction.

Brick ledge

Part of the foundation wall where brick (veneer) will rest.

Brick lintel

The metal angle iron that brick rests on, especially above a window, door, or other opening.

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Brick mold

Trim used around an exterior door jamb that siding butts to.

Brick tie

A small, corrugated metal strip @ 1" X 6"- 8" long nailed to wall sheeting or studs. They are inserted into the grout mortar joint of the veneer brick, and holds the veneer wall to the sheeted wall behind it.

Brick veneer

A vertical facing of brick laid against and fastened to sheathing of a framed wall or tile wall construction.

Bridge

To place a ladder to span a gap usually between two structures; a hose bridge to prevent damage to hose from traffic passing over it.

Bridge gun           

 See line gun.

Bridging (construction) 

Small wood or metal members that are inserted in a diagonal position between the floor joists or rafters at mid-span for the purpose of bracing the joists/rafters and spreading the load.

British thermal unit [Btu]

The amount or quantity of heat required to raise the temperature of one pound of water one degree Fahrenheit at sea level

Broken stream

Stream of water that has been broken into coarsely divided drops.

Brush apparatus

Fire department apparatus designed specifically for fighting wildland fires. Also called Booster Apparatus, Brush Patrol, Brush Pumper, and Field Unit.

Buck

Often used in reference to rough frame opening members. Door bucks used in reference to metal door frame. See Window Bucks

Buff

A person, other than a firefighter, who is interested in fires, fire departments, and firefighters.

Bugles

Insignia depicting early speaking trumpets used to designate the rank of fire department personnel.

Building code

A list of rules, usually adopted by city ordinance, to regulate the safe construction of buildings. There are several building codes that are widely adopted in the United States including the Southern Standard Building Code, the Uniform Building Code, the Basic Building Code, the International Building code, The Building Official Conference of America (BOCA) and the National Building Code.

Building paper

A general term for papers, felts, and similar sheet materials used in buildings without reference to their properties or uses. Generally comes in long rolls.

Building survey

The portion of the pre-incident planning process during which the company travels to a building and gathers the necessary information to develop a pre-incident plan for the building.

Built-up roof

A roofing composed of three to five layers of asphalt felt laminated with coal tar, pitch, or asphalt. The top is finished with crushed slag or gravel. Generally used on flat or low-pitched roofs.

Bull nose (drywall)

Rounded drywall corners.

Bumper line

Pre-connected hose line located on the apparatus bumper.

Bundle 

A package of shingles. Normally, there are 3 bundles per square and 27 shingles per bundle.

Bunk

 A firefighter’s bed.

Bunk room

The dormitory area where firefighters sleep.

Bunker clothes

An entire set of firefighter's protective clothing. Also known as turnout clothes, turnouts, bunker gear

Bunker gear

An entire set of firefighter’s protective clothing that includes helmet, coat, pants, boots, and gloves; protects from heat, cold, and injury. Also known as turnout gear, bunkers, bunker clothing.

Bureau                  

A major subdivision within the fire department: Fire Prevention Bureau, Training Bureau, etc.

Burning point

A temperature point at which a material evolves sufficient vapors that when ignited will continue to burn. See Flash Point, fire point and ignition temperature..

Burning, phases of

A fire normally progresses through three distinct phases of burning or stages of burning: incipient, free burning, smoldering; newer terms include incipient, steady state, decay state.

Burnout

A building that has been denuded of almost all combustible material. Also refers to a burned wild land area.

Burns, Degree of

First degree: reddened skin; second degree: blisters; third degree: deep skin destruction. Major types of burns: heat, chemical, electrical, and radiation. The degree of burns traditionally classified according to the depth of tissue damage that is produced.

Butt 

One coupling of a fire hose; a hydrant outlet; the heel (lower end) of a ladder; the act of steadying a ladder that is being climbed.

Butt edge

The lower edge of the shingle tabs.

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Butt hinge

The most common type. One leaf attaches to the door's edge, the other to its jamb.

Butt joint

The junction where the ends of two timbers meet, and also where sheets of drywall meet on the 4 foot edge. To place materials end-to-end or end-to-edge without overlapping.

Butterfly valves

A type of control valve used in water supply distribution systems. Type of control valve that uses a flat baffle operated by a quarter-turn handle.

Butyl rubber

A synthetic rubber used in chemical protective suits. A material commonly used in the manufacture of chemical protective clothing. A synthetic rubber, made by the copolymerization of butylene with butadiene or isoprene.

By fold door

Doors that are hinged in the middle for opening in a smaller area than standard swing doors. Often used for closet doors.

By pass doors