Firefighter Dictionary: C

The following is common terminology to structural fire firefighters. There are additional definitions for emergency medical terminology, building construction, arson investigation and hazardous materials and more. Please note that some definitions have more than one meaning but are spelled the same. Click on a letter to take you to that index.

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z 

C

C

Degrees Celsius, centigrade.

Cable hanger

A device used to test the structural strength of aerial ladders.

Cache

A pre-determined complement of tools, equipment, and/or supplies stored in a designated location, available for incident use

Caisson

A 10" or 12" diameter hole drilled into the earth and embedded into bedrock 3 - 4 feet. The structural support for a type of foundation wall, porch, patio, monopost, or other structure. Two or more "sticks" of reinforcing bars (rebar) are inserted into and run the full length of the hole and concrete is poured into the caisson hole

Cal

 Abbreviation for Calorie.

Calibrate

To standardize or adjust the increments on a measuring instrument.

Calorie (cal)

The quantity of heat required to raise the temperature of 1 gram of water 1 degree Celsius. calorimeter A device for measuring the energy absorbed from a source of electromagnetic radiation.

CAMEO

Acronym for  Computer-Aided Management of Emergency Operations.

Camp

A geographical site, within the general incident area, separate from the Incident Base, equipped and staffed to provide sleeping, food, water, and sanitary services to incident personnel.

Candlepower (cp)

The unit of light intensity or brightness of a standard candle at hrs

Canister (Respirator)

A container filled with a sorbet, and possibly catalysts, used for removing contaminants (gases or vapors) from air being inspired through the device.

Canister, oxygen generated

A container of chemicals that create oxygen when the individual's breath is mixed with them. Similar to all service masks. This is old technology and for the most part have been taken out of service due to the heat the canisters generate. The canisters were known to explode when the heated can came in contact with water.

Cannula (Nasal)

A device consisting of two short tubes that can be inserted into the nostrils for administering oxygen or other therapeutic gases.

Canopy

A projection over windows and doors to protect them from the weather.

Canopy hood

A one- or two-sided hood which is positioned above an operation that typically involves heating, to receive and remove the hot air and contaminants that are released and rise and enter the hood.

Canteen unit 

Emergency vehicle that provides food, drinks and other rehabilitative service to emergency workers at extended incidents. These services have been provided to some fire departments from the American Red Cross and the Salvation Army.

Cantilever

A projecting beam or structural member anchored at only one end. An overhang. Where one floor extends beyond and over a foundation wall. For example at a fireplace location or bay window cantilever. Normally, not extending over 2 feet.

Cap

The upper member of a column, pilaster, door cornice, molding, or fireplace.

Cap flashing

The portion of the flashing attached to a vertical surface to prevent water from migrating behind the base flashing.

Cap sheet

A finish saturated roofing felt used as a covering for a roof.

Capacity

Maximum ability of a pump or water distribution system to deliver water.

Capillary

Pertaining to or resembling a hair with a very small internal diameter. One of the minute blood vessels that connect the arteries and veins. 

Captain

Officer in charge of a fire station, or any other position of comparable responsibility in the department. The highest rank in an individual company unit.

Car

Radio term for officer’s vehicle. Some ambulance services refer to their vehicles as cars

Carbon dioxide (CO2)

A gas stored in cylinders and applied through a fixed or semi fixed system, of from a portable extinguisher. It is useful for inerting a closed area or for putting out small local fires. A heavier than air gas used in extinguishing Class B fires by smothering, or by displacing the oxygen. A fire gas produced by the complete combustion of a carbonaceous material. In solid form, a super cool temperature it is known as dry ice. A odorless, colorless gas, which can at high levels (above 1.5% or 15,000 parts per million), have physiological effects. Main indoor source is human respiration; measurements used as indicators of ventilation conditions.

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Carbon monoxide (CO)  

Carbon Monoxide is a colorless gas which has almost no odor. It is like smoke in that it is a product of incomplete combustion. Carbon monoxide is the by product of the burning of any material containing carbon in the solid liquid or gaseous state. Almost all of the fires encountered by firemen and fire investigators will involve certain amounts of carbon monoxide and smoke. It is a chemical asphyxiant; in the bloodstream it effectively prevents the transport of oxygen to the body's tissues. CO exposure can affect the lungs, heart, and nervous system, and can cause death. Sources include cooking and heating appliances, tobacco smoke, and entrained exhaust from parking garages and truck idling areas.

Carbonaceous

A material made of, or containing carbon. This includes almost every flammable material.

Carboy 

A container, usually encased in a protective basket or crate, to ship hazardous materials, particularly corrosives.

Carcinogen

An agent that produces or is suspected of producing cancer. A material that either causes cancer in humans or, because it causes cancer in animals, is considered capable of causing cancer in humans.

Cardio-pulmonary resuscitation (CPR)

A combination of artificial resuscitation and closed-chest cardiac (heart) compression

Cargo manifest

A shipping paper that contains all of the contents being carried by the transporting vehicle or vessel.

Carport

An automobile shelter not fully enclosed.

Carriage 

The horizontal part of the stringers of a stair that supports the treads.

Cartridge respirator

 A respirator using various chemical substances to purify inhaled air of certain contaminative gases and vapors. Typically effective for concentrations no more than 10 times the TLV for a half face piece and 100 times the TLV for a full-face piece, provided the contaminant has warning properties (odor or irritation) near the TLV.

CAS registry number

The American Chemical Society (ACS) uniquely assigns Chemical Abstracts Service (CAS) Numbers to molecules and mixtures. CAS numbers are often used by local and state hazardous materials compliance legislation for tracking chemicals in the workplace and in the community. These numbers provide a unique identification for chemicals as well as a means for crosschecking chemical names.

Cascade air cylinders

Large air cylinders that are used to refill smaller SCBA cylinders.

Cascade System

Personnel working in a hazardous area and wearing an SCBA are limited to around 30 minutes of breathing air by the size of the cylinder (usually 2500 psi) and their respiratory rate. When the cylinders are empty they must be refilled in order to be used again. A cascade system refers to larger capacity cylinders (between 4500 and 6000 psi) linked together and refilled by a compressor. The used SCBA cylinders are then connected to this system to be refilled. Many departments have the capability to do this on the scene and all have refill systems at their stations. Three or more large air cylinders, each usually with a capacity of 300 cubic feet (8490 L), that are interconnected and from which smaller SCBA cylinders are recharged

Casement

Frames of wood or metal enclosing part (or all) of a window sash. May be opened by means of hinges affixed to the vertical edges.

Casement window

A hinged window that opens out, usually made of metal. A window with hinges on one of the vertical sides and swings open like a normal door

Casing 

A covering put around something; a case. Trim around window and door openings. A steel pipe used as a lining in an oil well.

Catalyst 

A material that alters the energy necessary to produce a chemical reaction. If the energy is lowered, the reaction proceeds more quickly (the typical use for a catalyst). If the energy necessary is increased, the reaction is slowed. The catalyst is not consumed by the chemical reaction.

Catch a hydrant

The firefighter gets off the fire apparatus at the hydrant, connects a large diameter fire hose to the hydrant and turns on the water (hydrant) to supply the engine company with water.

Catch basin

 See Portable Tank.

Cause                                   

The circumstances, conditions, or agencies that bring together a fuel, ignition source, and oxidizer (such as air or oxygen) resulting in a fire or a combustion explosion.

Caustic

Burning or corrosive. A hydroxide of a light metal. Broadly, any compound having highly basic properties. A compound that readily ionizes in aqueous solution to yield OH-anions, with a pH above 7, and turns litmus paper blue. See Alkaline, Base.

Cavitation

If pressure at any point inside a pump drops below the vapor pressure corresponding to the temperature of the liquid, the liquid will vaporize and form cavities of vapor. The vapor bubbles are carried along with the stream until it reaches a region of higher pressure. Then they collapse or implode with a tremendous shock on the adjacent impeller walls.

Cavity wall

Double masonry wall having an air space between the wyths. A wyth is each continuous vertical section of masonry one unit in thickness

CCA (Chromated Copper Arsenate)

A pesticide that is forced into wood under high pressure to protect it from termites, other wood boring insects, and decay caused by fungus

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CDC (Center for Disease Control)

This Department of Health and Human Services agency includes the National Center for Chronic Disease Prevention and Health Promotion; National Center for Environmental Health; National Center for Health Statistics; National Center for HIV, STD and TS Prevention; National Center for Infectious Diseases; National Center for Injury Prevention and Control; National Institute for Occupational Safety and Health; Epidemiology Program Office; International Health Program Office; Public Health Practice Program Office; and the National Immunization Program.

Cedar shingles

Roofing and siding shingles made from western red cedar.

Ceiling exposure value

The maximum airborne concentration of a biological or chemical agent to which a worker may be exposed at any time.

Ceiling joist

One of a series of parallel framing members used to support ceiling loads and supported in turn by larger beams, girders or bearing walls. Also called roof joists.

Ceiling layer

A buoyant layer of hot gases and smoke produced by a fire in a compartment.

Ceiling limit

An occupational exposure limit that must not be exceeded at any time. Both OSHA and NIOSH state that exposure to continuous, varying, intermittent or impulsive noise shall not exceed 140 dBA.

Ceiling plenum

The space between the suspended and structural ceiling, used as part of the air distribution system. This space usually accommodates electrical, communications, and mechanical connections as well.

Cellar pipe

Special nozzle for attacking fires in basements, cellars, and other spaces below ground level.

Cellular asphyxiant

A material that upon entering the body inhibits the normal function of cells. Examples are CO, hydrogen cyanide, or hydrogen sulfide poisoning.

Cement

The gray powder that is the "glue" in concrete. Portland cement. Also, any adhesive.

Central Fire Station

Headquarters station that contains administrative offices, special equipment, fire apparatus, and personnel.

Central Nervous System (CNS)

In humans, the brain and spinal cord, as opposed to the peripheral nerves found in the fingers, etc.

Centrifugal pump

 A fire pump using centrifugal force (force to the outside) to develop and impart velocity to the water as it passes through the pump. There are single and multistage centrifugal pumps. Pump with one or more impellers that utilize centrifugal force to move the water. Most modern fire pumps are of this type.

CERCLA

Acronym for Comprehensive Environmental Response, Compensation, and Liability Act.

Certificate of Occupancy (CO)

An abbreviation for "Certificate of Occupancy". This certificate is issued by the local municipality and is required before anyone can occupy and live within the home. It is issued only after the local municipality has made all inspections and all monies and fees have been paid.

Certification tests

Pre-service tests for aerial device, ladder, pump, and other equipment conducted by an independent testing laboratory prior to delivery of an apparatus. These tests assure that the apparatus or equipment will perform as expected after being placed into service.

C-Factor

Numerical value factor that indicates the roughness of the inner surface of piping or fire hose. Used for calculating how friction loss affects gallons per minute. There are several formulas for computing the carrying capacities of water mains.  The one most commonly used in the water works industry is the Hazen-Williams Formula.  A factor called "C" represents the coefficient of  friction.  It is a measure of the roughness of the interior surface of pipe.  A "C" factor of 140 would indicate a very smooth pipe, whereas a "C" factor of 70  would indicate a very rough pipe.  The smoother the surface of the pipe wall, the larger the value of "C" and, consequently, the greater the carrying capacity.

CFM 

Abbreviation for cubic feet per minute. A rating that expresses the amount of air a blower or fan can move. The volume of air (measured in cubic feet) that can pass through an opening in one minute.

CFR

Crash, Fire Rescue personnel; trained in aircraft firefighting and rescue. Code of Federal Regulations; enforced by federal and state agencies and containing statutes for the function of federal government.

CGI 

See Combustible Gas Indicator.

Chafing block

Blocks placed under hose lines to protect the hose covering from damage due to rubbing against the ground or concrete.

Chain hose tools

Chain, strap, and rope hose tools used to carry, secure, and otherwise aid in handling hose.

Chain of Command

A series of command, control, executive, or management positions in hierarchical order of authority. The order of rank and authority in the fire service.

Chain reaction

A series of self sustaining changes each of which causes or influences a similar reaction. See tetrahedron.

Chair rail

Interior trim material installed about 3-4 feet up the wall, horizontally.

Char 

Carbonaceous material that has been burned and has a blackened appearance.

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Char blistering

Convex segments of carbonized material separated by cracks or crevasses that from on the surface of char, forming on materials such as wood as the result of pyrolysis or burning. See Alligatoring.

Charge

The act of pressurizing a fire hose or fire extinguisher.

Charged building

A building heavily laden with smoke and gases, and possibly in danger of having a backdraft.

Charged Hose

A line that has been pressurized by the pump operator so that it is ready for use by the firefighting personnel.

Charged line

Hose loaded with water under pressure and prepared for use.

Charles's Law

 If the volume of a gas is kept constant and the temperature is increased, the pressure increases in direct proportion to the increase in absolute temperature. A gas will expand or contract in direct proportion to increase or decrease in temperature. If a gas is confined so that it will not expand, its pressure will increase or decrease in direct proportion to temperature.

Chase

A framed enclosed space around a flue pipe or a channel in a wall, or through a ceiling for something to lie in or pass through.

Chauffeur

See Fire Apparatus Driver/ Operator.

Check valve

An automatic valve that permits flow in only one direction.

Check-In

The process whereby resources first report to an incident. Check-in locations include: Incident Command Post (Resources Unit), Incident Base, Camps, Staging Areas, Helibases, Helispots, and Division Supervisors (for direct line assignments).

Checking the building

Fire size-up term used when equipment arrives on the scene of an incident and no fire or smoke are visible. The act of determining if there is an actual fire. Same as Investigation.

Checklist 

Detailed lists generally prepared for the maintenance of equipment or apparatus, or for installed fire protection equipment to ensure that the inspector does not over­look an item that needs to be checked regularly. They may also be used during pre-fire planning and fire prevention inspections.

Chemical burn                   

A burn that occurs when the skin comes into contact with strong acids, strong alkalis, or other corrosive materials. These agents literally eat through the skin and in many cases continue to do damage so long as they remain in contact with the skin.

Chemical Chain Reaction

Vapor or gases are distilled from flammable materials during initial burning. Atoms and molecules are released from these vapors and combine with other radicals to form new compounds. These compounds are again disturbed by the heat releasing more atoms and radicals that again form new compounds and so on. See tetrahedron.

Chemical compound

A new homogeneous substance consisting of two or more elements and having properties different from the constituent elements.

Chemical foam

A foam formed when an alkaline solution and an acid solution unite to form a gas (carbon dioxide) in the presence of a foaming agent that traps the gas in fire-resistive bubbles.

Chemical name 

The scientific designation of a chemical or a name that clearly identifies the chemical for hazard evaluation purposes. All pharmaceuticals have a chemical name, generic name and a product name.

Chemical properties

Properties of a material that relate to toxicity, flammability, or chemical reactivity. A property of matter that describes how it reacts with other substances.

Chemical reaction

A process that involves the bonding, unbonding, or rebonding of atoms. A chemical change takes place that actually changes substances into other substances.

CHEMTREC

Abbreviation for the Chemical Transportation Emergency Center. Established in Washington, D.C., by the Chemical Manufacturers Association (CMA) to provide emergency information on materials involved in transportation accidents. CHEMTREC can contact the shipper or producer of the material for more detailed information on the chemical released, to facilitate response and cleanup actions. 24-hour number: (800) 424-9300. In Washington D.C., Alaska, or Hawaii call (202) 483-7616.

Chief 

The ICS title for individuals responsible for management of functional Sections: Operations, Planning, Logistics, Finance/Administration and Intelligence (if established as a separate section). A fire department officer of greater than company officer rank. The chief administrative officer of the fire department and chief command officer at any fire

Chief of Department 

The highest ranking member of the fire department; in some instances, designated as the director or administrator.

Chief Officer

Any of the higher officer grades, from district or battalion chief to the chief of the fire department.

Chimney Bucket

The name given to the container which normally holds a chimney chain, a small shovel, and fire retardant gloves. The chain is taken out and the bucket and shovel are taken inside the structure to remove anything that may still be burning in the fireplace. This is done in order to aid in the extinguishment of a chimney fire.

Chimney Chain

This is a special chain that has a number of smaller chains attached to one end. While in communication with the fire personnel inside of the structure the chain is dropped down the chimney and spun in a circular pattern to remove the burning creosote from the chimney lining. It is then gathered into the chimney bucket by the fire personnel inside of the structure and taken outside for extinguishment.

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Chink

To install fiberglass insulation around all exterior door and window frames, wall corners, and small gaps in the exterior wall.

Chip Board

A manufactured wood panel made out of 1"- 2" wood chips and glue. Often used as a substitute for plywood in the exterior wall and roof sheathing. Also called OSB (Oriented Strand Board) or wafer board.

Chlorep

The chlorine emergency plan, established by the Chlorine Institute, enables the nearest producer of chlorine to respond to an incident involving chlorine. (Contact is made through CHEMTREC.)

Chlorine kits

Standardized kits commercially manufactured by contract with the Chlorine Institute to provide equipment to control or stop leaks in chlorine cylinders, tanks and transportation tank cars. These kits come in different sizes depending on what type of container or vessel the chlorine is in at the time of the leak.

Chocks

 Wooden, plastic, or metal blocks constructed to fit the curvature of a tire; placed against the tire to prevent apparatus rolling.

Chronic effects

An adverse health effect on a human or animal body with symptoms that develop slowly or that recur frequently due to the exposure of hazardous chemicals.

Chronic exposure

Low doses repeatedly received by the body over a long period of time. Repeated doses or exposure to a material over a relatively prolonged period of time.

Chronic Obstructive Pulmonary Disease (COPD)

A chronic obstruction of bronchial airflow resulting in decreased pulmonary ventilation.

Chronic poisoning

Poisoning that is a result of repeated exposure to sub-lethal doses over a period of time.

Chuck 

 A portable fire hydrant carried on the apparatus with one or more gated connections for fire hose. The device screws into a special flush hydrant connection on the water main or a special main. Also an air line connection.

Church raise

See auditorium raise.

Chutes

A channel constructed of salvage covers for water runoff. Also a means of escape from large aircraft.

Circuit 

The path of electrical flow from a power source through an outlet and back to ground.

Circuit Breakers

A circuit breaker is a part of the electrical path. It operates much like a switch, except it opens automatically when a predetermined amount of electricity passes through it. Circuit breakers usually operate when moderate overloads occur for continuous periods by means of a thermally responsive element and when very high electrical values are reached by means of a magnetically responsive element. The magnetic element is not affected by temperature, but the thermal element will have different response times in different ambient temperatures. A device which looks like a switch and is usually located inside the electrical breaker panel or circuit breaker box. It is designed to (1) shut of the power to portions or all of the house and (2) to limit the amount of power flowing through a circuit (measured in amperes). 110 volt household circuits require a fuse or circuit breaker with a rating of 15 or a maximum of 20 amps. 220 volt circuits may be designed for higher amperage loads e.g. a hot water heater may be designed for a 30 amp load and would therefore need a 30 amp fuse or breaker.

Circulating feed

Fire hydrant that receives water from two or more directions.

Circulating relief valve

Small relief valve that opens and provides enough water flow into and out of the pump to prevent the pump from overheating when it is operating at churn against a closed system

Circulating system

See Loop System.

Circulator valve

Device in a pump that routes water from the pump to the supply to keep the pump cool when hose lines are shut down.

Circumstantial evidence

Facts from which presumptions or inferences are made. Indirect evidence. (For example, seeing a person flee from the scene of a crime is circumstantial, indirect evidence that the person committed the crime; seeing a person commit a crime is direct evidence.)

Cistern 

A water storage container, usually below grade level, for emergency use including fire protection.

Clapper valve

Hinged valve that permits the flow of water in one direction only.

Class A combustibles         

Ordinary combustibles, which leave a residue after burning.

Class A explosive

A material or device that presents a maximum hazard through detonation.

Class A fire

Refers to a fire involving ordinary combustibles such as wood, paper, cloth, and so on that is best extinguished by cooling action (water).

Class A foam 

Foam specially designed for use on Class A combustibles. Class A foams are essentially wetting agents that reduce the surface tension of water and allow it to soak into combustible materials easier than plain water.

Class A poison

A poisonous gas or liquid of such nature that a very small amount of the gas, or vapor of the liquid, is dangerous to life.

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Class B combustible

Flammable liquids and gases.

Class B explosive

A material or device that presents a flammable hazard and functions by deflagration

Class B fire

Refers to fires of flammable and combustible liquids, and gases like gasoline, kerosene, and propane. They are usually extinguished by smothering agents (dry chemical—CO2).

Class B foam 

Foam specially designed for use on Class B flammable and combustible liquids. New variants are designed for polar solvents. Types include AFFF and AR-AFFF.

Class B poison

A substance that is known to be so toxic to human life that it affords a severe health hazard during transportation.

Class C combustibles

Class A or B fires that occur in or near electrical equipment.

Class C explosive

A mate