A

A

Abbreviation for ampere(s).

A end

The end opposite the handbrake or "B" end of the tank car.

A/B switch 

A switch that selects one of two inputs (A or B) for routing to a common output.

A/B/C/D sides

At a building fire, the sides of buildings are identified by ABCD sides, with side A being the front of the building, and sides BCD being named around the building in a clockwise fashion. This helps maintain clear communication on the fireground for location of assignments or firefighters.

A/C

An abbreviation for air conditioner or air conditioning.

A/C Condenser 

The outside fan unit of the Air Conditioning system. It removes the heat from the freon gas and "turns" the gas back into a liquid and pumps the liquid back to the coil in the furnace.

A/C Disconnect 

The main electrical ON-OFF switch near the A/C Condenser.

AAR

Abbreviation for American Association of Railroads. AAR is a subdivision of the Department of Transportation.

Abatement

The actions taken to reduce the amount, degree of the hazard, or intensity of the release or threatened release of a hazardous material.

ABC extinguisher

A fire extinguisher that can be used on fires involving ordinary combustibles, flammable liquids, and energized electrical equipment; may also be known as a multipurpose extinguisher.

Absolute pressure    

Pressure measured with respect to zero pressure or a vacuum. It is equal to the sum of a pressure gauge reading and the atmospheric pressure at the measurement location.

Absolute temperature

Temperature based on an absolute scale expressed in either degrees Kelvin (K) or degrees Rankine (R), corresponding respectively to the centigrade (C) or (F) scales. Degrees Kelvin is obtained by adding 273 to the centigrade temperature, or subtracting the centigrade temperature, from 273 if below 0°C. Degrees Rankine are obtained by algebraically adding the Fahrenheit reading to 460. Zero degrees K is equal to -273°C, and 0 degrees R is equal to -459.69°F.

Absolute zero

The minimum point on the thermodynamic temperature scale, which is 0 degrees Kelvin, -273.16 degrees centigrade, 0 degrees Rankine, or -459.69° Fahrenheit. This is a hypothetical temperature at which there is a total absence of heat.

Absorb

The penetration of one substance into the body of another.

Absorbent

A solid material that takes in liquids or gaseous substances (like a sponge) and undergoes chemical and/or physical changes as a result. Penetration can be capillary, osmotic, solvent, or chemical. Some of the materials typically used, as absorbents are sawdust, clays, charcoal, and polyolefin type fibers.

Absorption

The process of an agent being taken in by a surface (clothing, fabrics, wood, etc.,) much like a sponge and water. A route of exposure. It occurs when a toxic material contacts the skin, and then enters the bloodstream by passing through the skin.

AC

Alternating current.

Academy 

A training school; a place to train, learn, study, and achieve

Accelerant

An agent used to initiate or speed the spreading of fire. The most common accelerants are flammable or combustible liquids.

Accelerator

A device attached to a dry-pipe sprinkler system for rapid removal of air in the system; a device to control the speed of a vehicle by regulating the fuel supply.

Acceptable entry conditions 

Conditions that must exist in a confined space before entry is permitted to ensure that personnel can safely enter and carry out the work.

Acceptable risk

A risk, judged to be outweighed by corresponding benefits, or one that is of such a degree that it is considered to pose minimal potential for adverse effects.

Access corridor

A designated geographic area through which entrance into the "hot" or exclusion mitigation personnel permit zone. Typically, the access corridor serves as, or is near, the decontamination corridor and borders the hot and warm zones.

Accident

An unexpected and uncontrolled event generally resulting in injury, loss of property or disruption of services. A chance occurrence arising from unknown causes; an unexpected happening due to carelessness, ignorance, and the like. Any unplanned event that interrupts or interferes with the orderly progress of a production activity or process.

Accident prevention

Efforts or counter measures that are taken to reduce the number and severity of accidents.

Accordion fold

A fold for salvage covers.

Accordion load

A system of loading hose in the hose bed of a fire truck.

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Acetyl cholinesterase

An enzyme (a protein produced in the cells) which stops (inactivates) the action of acetylcholine by separating the acetylcholine into its components of acetic and chorine. This occurs as soon as acetylcholine has produced a muscle contraction. Nerve agents combine with acetyl cholinesterase to prevent it from performing its inactivation of acetylcholine.

Acetylcholine   

A chemical compound formed from an acid and an alcohol that causes muscles to contract (neurotransmitter). It is found in various organs and tissues of the body. It is rapidly broken down by an enzyme, cholinesterase.

Acid                               

A hydrogen-containing corrosive material that reacts with water to produce hydrogen ions; a proton donor. Any of a class of chemical compounds whose aqueous solutions turn litmus paper red (have a pH less than 7) or reacts with and dissolves certain metals or reacts with bases to form salts. A compound capable of transferring a hydrogen ion in solution. A molecule or ion that combines with another molecule or ion by forming a covalent bond with two electrons from the other species.

Acquifer

A saturated water bearing formation of permeable rock sand or gravel.

Action level

A qualitative limit of chemical, biological, or radiological agent at which actions are taken to prevent or reduce exposure or contact.

Action Plan

See Incident Action Plan

Active ingredient 

The chemical that has pesticide action. Active ingredients are listed in order on a pesticide label as percentage by weight or as pounds per gallon of concentrate. See Inert Ingredients.

Actual breakthrough time    

The average time elapsed between initial contact of the chemical with the outside surface of the fabric and the detection time.

Actuate

To set into operation, especially an installed fire protection system.

Acute effects  

An adverse effect on a human or animal body, with symptoms developing rapidly. See Chronic Effects.

Acute exposure

A dose that is delivered to the body in a single event or in a short period of time. The adverse effects resulting from a single dose or exposure to a material. Ordinarily used to denote effects observed in experimental animals.

Acute poisoning

Poisoning by a single exposure to a toxic chemical.

Acute toxicity

Any harmful effect produced by a single short-term exposure that may result in severe biological harm or death.

Adapter 

A device to make a connection when the threads do not match or when they are different sizes.

Adiabatic compression        

A term used to describe the generation of heat when a liquid or gas is compressed. If a flammable mixture is compressed rapidly, heat produced by the compression may be sufficient to raise the temperature of the mixture to its ignition point.

Adsorbent

A material that attracts molecules of a liquid or gas to its surface without undergoing chemical or physical alteration.

Adsorption   

The process of an agent sticking to or becoming chemically attached to a surface.

Advanced Life Support 

Advanced life support (ALS) is medical care provided by paramedics trained to assess a patient's condition, administer drugs, defibrillate and provide advanced airway management prior to transportation to the hospital.

Advancing a line

A line in the fire service is a line of hose. Advancing a line, therefore, is moving a line of hose forward toward a given assigned area from point where the hose-carrying apparatus has stopped. Also called "stretching a line".

AED

An automated external defibrillator (AED) detects and treats cardiac arrest due to the cardiac arrhythmias, ventricular fibrillation (VF) and ventricular tachycardia (VT). Uncorrected, these arrhythmias rapidly lead to irreversible brain damage and death. Unlike regular defibrillators, an automated external defibrillator automatically determines if a shock is indicated, and automatically selects and delivers the appropriate energy level. Once the pads are attached to the patient, the machine diagnoses the heart rhythm and determines if a shock is needed to treat ventricular tachycardia or ventricular fibrillation. If the machine determines that a shock is necessary, it will charge in preparation to deliver the shock. When charged, the machine instructs the user to ensure no one is touching the patient and then to press a button to actually deliver the shock.

Aerial ladders 

A mechanically-operated ladder on a turn table attached to a ladder truck chassis and manufactured in various lengths, generally from 65 feet  to 100 feet.

Aerial platform apparatus  

See elevating platform apparatus

Aerial Truck    

Also known as a ladder truck or just plain truck.  A hydraulically powered ladder, mounted on a vehicle that also carries several different length extension ladders, extrication gear, ventilation equipment, and lighting.  May or may not have a bucket or platform on the end. 

Aerosol  

Micron-size liquid droplets or solid particles dispersed in air by pressurized gases. When liquid droplets reach micron dimensions, their behavior becomes similar to solid particles of the same size. A suspension or dispersion of small particles (solids or liquids) in a gaseous medium. The dispersion of very fine particles of a solid or liquid in a gas, fog, foam, or mist.

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AFFF (Aqueous Film Forming Foam)  

An acronym for Aqueous Film Forming Foam. It is a highly efficient type of fire suppressant agent used to attack flammable liquid fuel fires. This concentrated liquid is mixed with water and dispersed using a proportioning nozzle. The foam forms spontaneously upon ejection from the nozzle. The AFFF coats the pool of hydrocarbon fuel with a layer of foam which acts like a thermal and evaporation barrier to inhibit and eventually extinguish combustion. The "film forming" characteristics refers to the fact that even after the foam has dissipated, the aqueous layer formed from the water and concentrate mixture can coat a liquid hydrocarbon surface

A-Frame      

A structural system utilizing members which when fastened together resemble the letter A.

A-frame ladders 

The type of ladders that are hinged in the middle and can be used as either A-frame stepladders or as baby extension ladders.

Agency  

An agency is a division of government with a specific function, or a nongovernmental organization (e.g., private contractor, business, etc.) that offers a particular kind of assistance. In ICS, agencies are defined as jurisdictional (having statutory responsibility for incident mitigation) or assisting and/or cooperating (providing resources and/or assistance). (See Assisting Agency, Cooperating Agency, Jurisdictional Agency, and Multi-agency Incident.)

Agency Administrator or Executive  

Chief executive officer (or designee) of the agency or jurisdiction that has responsibility for the incident

Agency Dispatch  

The agency or jurisdictional facility from which resources are allocated to incidents.

Agency Representative 

An individual assigned to an incident from an assisting or cooperating agency who has been delegated authority to make decisions on matters affecting that agency's participation in incident management activities following appropriate consultation with the leadership of that agency. Agency Representatives report to the Incident Liaison Officer.

Agent     

Agent refers to extinguishing material used in the fire service.

Aggregate                   

A mixture of sand and stone and a major component of concrete.

Agricultural chemicals 

Chemicals such as pesticides, herbicides, fungicides, insecticides and fertilizers used in agricultural applications to control pests and disease or control/promote growth.

Air bag

An inflatable bag, often made of synthetic rubber, used to lift or stabilize heavy objects. Also a large inflatable bag into which persons can leap to escape danger.

Air bottle

 A thick walled steel, fiberglass wrapped aluminum cylinder or composite metal cylinder equipped with a control valve, pressure gauge, and nipple outlet for a high pressure hose connection. In the fire service these tanks contain compressed air or oxygen. Each bottle carries approximately 66 cubic feet of  compressed air at a pressure of 4500 pounds per square inch. See SCBA

Air bourne contaminants

Solid, liquid or gaseous materials that are mixed in the air and spread with air movements. Chemical vapors will readily mix with moving air. In still air, heavier gases-such as chlorine and gasoline fumes- will settle, whereas lighter gases-such as natural gas or hydrogen-will rise. Aerosols consisting of micron-size solid particles and liquid droplets can also be suspended in moving air but will settle at low air velocities or larger sizes. Asbestos, lead paint dusts, some agricultural chemicals, silica, radioactive particles, viruses, fungal spores, pollen and bacteria are examples of other airborne contaminants of concern.

Air chamber   

A chamber filled with air and that serves to eliminate the pulsations caused by the operation of piston or rotary-gear pumps; a pulsation eliminator.

Air distribution system  

The means by which cooling and/or breathing air is delivered to and distributed in a protective suit.

Air duct

A pipe, usually made of sheet metal, that conducts air to rooms from a central source

Air foam

A term used to describe mechanical foam, as differentiated from chemical foam; the type of foam concentrate that is added to the water and agitated or aerated to produce the Class B agent.

Air inversion

A meteorological condition in the earth's atmosphere in which the temperature of the air some distance above the earth's surface is higher than the air temperature of the surface. Normally, air temperatures decrease progressively as altitude increases. Such a condition traps air and released gases and vapors near the earth's surface, thus impeding their dispersion.

Air lock                        

A situation that can develop in a centrifugal pump that has not been properly primed. The rapid revolution of the impeller may create an air lock, which prevents priming of the pump.

Air mask or air pack

Worn by firefighters, a type of self-contained breathing device that provides an air supply from tanks through a regulator. See breathing equipment or SCBA

Air Operations Branch Director

The person primarily responsible for preparing and implementing the air operations portion of the Incident Action Plan. Also responsible for providing logistical support to helicopters operating on the incident.

Air pocket 

A condition that occurs when a portion of non-collapsible intake hose is elevated higher than the intake of the pump when drafting; a void created by a cave-in; a confined space where air is trapped in the top of a car that has sunk beneath the water.

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Air pressure sprinkler system

A sprinkler system in which air pressure is used to force water from a storage tank into the system.

Air purification respirator (APR)

A device worn to filter particulates and contaminants from the air. An APR should only be worn in atmospheres where the type, size, and quantity of the contaminants are known and sufficient oxygen is present. Respirator that removes a contaminant from the air being inhaled by the wearer by passing air through a filter or cartridge containing a solid sorbent, such as activated charcoal, before the air is inhaled.

Air reactive materials 

Substances that will ignite at normal temperatures when exposed to air.

Air space

The area between insulation facing and interior of exterior wall coverings. Normally a 1" air gap.

Air spring

A flexible air-inflated chamber in which the air pressure is controlled and varied to support the load and absorb road shocks; formerly called air bag

Air supply unit

A machine to refill exhausted compressed

Air Tank 

See Air Bottle.

Aircraft emergencies

Alert 1: In-bound aircraft with possible onboard dilemma. Emergency response forces maintain readiness at response station for further development.

Aircraft fire protection

A specialized branch of the fire service dealing with airports or aircraft.

Airline mask  

A mask worn by firefighters, connected to an air supply outside a contaminated area.

Airway 

A medical term referring to the passageway from the mouth/nose to the lungs of a patient. A metal or plastic framework designed to fit the curvature of the mouth and throat to prevent air passageways from closing.

Al  

See Aluminum Alloy.

Alarm  

Any signal indicating the need for emergency fire ser­vice response; also, the device that transmits the alarm.

Alarm Assignment

A designation, usually in advance of the event, of the units to respond to a given fire alarm or signal; the entire complement assigned to any given alarm. As "the entire first alarm assignment went to work." (Example: two engines, one ladder, one battalion chief - a typical structure fire assignment).

Alarm Circuit  

An electrical circuit connecting two points in an alarm system; for example, from the signal device to the fire station, from the central alarm center to all fire stations, or from the sending device to the audible alarm devices.

Alcohol foam

Blankets fires in the same manner as conventional foam, but it are intended for use with liquids, which are soluble in water, such as alcohol and acetone. It must be applied more carefully than regular foam because the mechanical strength of the bubbles is less.

Alcove

A recessed space connected at the side of a larger room.

Aldehydes   

A group of highly reactive organic compounds that contain the common group CHO (carbon-hydrogen-oxygen), such as formaldehyde.

Alkali

A hydroxide-containing corrosive material that is soluble in water, neutralizes acids and is irritating or destructive to tissue. An alkali is a chemical substance that has a pH above 7 (also called "base"). The higher the pH of an alkali, the stronger the chemical is (or more "caustic"). Alkalis are often called detergent builders and are the major active ingredient in most carwash detergents, especially powdered products. The level of alkalinity in a detergent solution is often considered the true measure of a detergent's strength.

Alkaline

Any compound having the qualities of a base. Simplified, a substance that readily ionizes in aqueous solution to yield hydroxyl (OH-) anions. Alkalis have a pH greater than 7 and turn litmus paper blue.

All hands

A working fire engaging all apparatus of first-alarm assignment; may be followed by multiple alarms.

All service masks

A canister-type filter mask resembling a gas mask canister. (No longer approved or recognized for firefighting.)

Allergen  

A substance that can trigger an immune response, resulting in an allergic reaction; also known as antigen. Allergens include living agents-such as bacteria, fungi, amoebae, and algae-and nonliving biological products-house dust, animal dander, spores, and insect feces.

Allergic asthma

An allergic illness that can be triggered by a variety of biological agents and exacerbated by such factors as cigarette smoke, sulfur dioxide, and emotional stress. It causes bronchiospasm, edema of the bronchial mucosa, and accumulation of bronchial mucous. Symptoms include coughing, wheezing, shortness of breath, itching of the nose, and rhino rhea.

Allergic illness

An illness caused by an allergen, usually upon second exposure. Although often associated with biological substances, allergic diseases may also be triggered by certain chemicals. Airborne exposure to allergens may occur on the skin, the nose, airways, even the lung alveoli. Antigenic material less than 5 μm such as mold spores, can penetrate the pulmonary region. Larger bioaerosols, such as pollens, tend to affect the upper respiratory tract. Allergic illnesses include allergic rhinitis, allergic asthma, allergic bronchopulmonary aspergillosis, hypersensitivity pneumonitis, and humidifier fever.

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Allergy  

An increased reactivity to an antigen as a result of previous exposure.

Alligatoring 

Convex portions of a carbonized material, separated by cracks or crevasses that form on the surface of char. Commonly forming on materials such as wood, as the result of pyrolysis or burning. Also called Char Blistering.

Allocated Resources

Resources dispatched to an incident

All-Risk

Any incident or event, natural or human-caused, that warrants action to protect life, property, environment, public health and safety, and minimize disruption of governmental, social, and economic activities

Alpha rays

Made up of very large particles, which are the same as the nucleus of the helium atom.

Alteration 

A change in, or addition to, an existing building.

Alternating Current (ac)               

A flow of electricity which reaches maximum in one direction, decreases to zero, then reverses itself and reaches maximum in the opposite direction. The cycle is repeated continuously. The number of cycles per second is equal to the frequency.

Aluminum alloy 

A physical blend of metals with aluminum as the major constituent. Aluminum is a common material used for containerizing materials for transport because of its lightweight property.

Aluminum alloy ladder 

A ladder made of aluminum and other materials like magnesium to make the ladder light­weight but strong.

Amalgam      

A mixture of different elements.

Ambient

Surrounding, especially pertaining to the local environment, as in ambient air and ambient temperature.

Ambient Temperature

The temperature of the atmosphere of surrounding environment. Typically defined by industry standards as 25° C

Ambulance    

A special vehicle equipped to transport sick or injured people to medical facilities.

Ambulatory  

A patient capable of walking; one who is not bedridden.

American National Standards

Serves as a clearinghouse for nationally coordinated Institute (ANSI) voluntary safety, engineering, and industrial standards developed by industrial firms, trade associations, technical societies, consumer organizations, and government agencies.

Ampere (A)

Unit of electrical current flow, or rate of flow of electrons. Ampere The unit used in the measure of the rate of flow of electricity.

Analysis 

The chemical determination of the composition of a substance.

Anchor bolt

A threaded rod inserted in masonry construction for anchoring the sill plate to the foundation.

Anemometer               

A device to sense and measure air velocity.

ANFO

An ammonium nitrate and fuel oil mixture, commonly used as a blasting agent. The manufacturer or user determines the proportions. It is commonly mixed with the addition of an "enhancer" such as magnesium or aluminum to increase the rate of burn.

Angergols 

Mixtures of fuels and oxidizers that do not react or ignite when combined.

Angle iron

A structural piece of rolled steel shaped to form a 90-degree angle.

Angle of approach

Angle formed by level ground and a line from the point where the front tires of a vehicle touch the ground to the lowest projection at the front of the apparatus.

Angle of departure

Angle formed by level ground and a line from the point where the rear tires of a vehicle touch the ground to the lowest projection at the rear of the apparatus

Anhydrous

Free from water, dry. Being without water, especially water of crystallization.

ANSI (The American National Standards Institute)

A clearinghouse for nationally coordinated voluntary safety, engineering and industrial standards developed by industrial firms, trade associations, technical societies, consumer organizations and government agencies.

Antenna

A device that collects and focuses electromagnetic energy, i.e., contributes an energy gain. Term usually applied to communication devices or equipment to receive and transmit radio frequencies.

Anticholinergic 

An agent or chemical that blocks or impedes the action of acetylcholine, such as the antidote atropine.

Anticholinesterase 

A substance that blocks the action of cholinesterase (acetylcholinesterase) such as nerve agents.

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Antidote

A substance, which neutralizes toxic agents or their effects

Anti-electrocution platform           

 Slide-out platform mounted beneath the side running board or rear step of an apparatus equipped with an aerial device. This platform is designed to minimize the chance of the driver/ operator being electrocuted should the aerial device come in contact with energized electrical wires or equipment.

Apparatus 

An engine-driven fire truck of any variety, or a group of fire trucks. The word is used for both singular and plural construction.

Apparatus Bay or Room

That area of the fire station in which apparatus is parked and stored.

Apparatus floor

The portion of a fire station on which fire trucks are parked.

Apparatus Operator

Engineer, driver, aerial ladder operator or anyone acting in any one of these positions. Can also be known as Fire Apparatus Operator or FAO

Appliance

This term refers to those objects that are used in connection with the hose lines but are not actually part of the hose themselves. This group contains, gated wyes, siamese, nozzles, deluge monitors and deck guns.

Applicator 

A special pipe or nozzle attachment for applying an extinguishing agent.

Applicator pipe

Curved pipe attached to a nozzle for precisely applying water over a burning object.