Online Companion: Firefighter's Handbook, Essentials of Firefighting and Emergency Response, 2e



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Abandonment Abandonment occurs when an emergency responder begins treatment of a patient and then leaves the patient or discontinues treatment prior to the arrival of an equally or higher trained responder.

Aboveground Storage Tank (AST)

Aboveground Storage Tank (AST) Tank that is stored above the ground in a horizontal or vertical position. Smaller quantities of fuels are often stored in this fashion.


Abrasion A scrape or brush of the skin usually making it reddish in color and resulting in minor capillary bleeding.


Absolute Pressure The measurement of pressure, including atmospheric pressure. Measured in pounds per square inch absolute.


Absorption A defensive method of controlling a spill by applying a material that absorbs the spilled chemical.


Accelerator A device to speed the operation of the dry pipe valve by detecting the decrease in air pressure. It pipes air pressure below the clapper valve, speeding its opening.


Accident The result of a series of events and conditions that lead to an unsafe situation resulting in injury and/or property damage.

Accident Chain

Accident Chain A series of events and conditions that can lead to or have led to an accident. These events and conditions are typically classified into five areas: environment, human factors, equipment, events, and injury.


Acclimation The act of becoming accustomed or used to something. Typically achieved through repeated practice within a given set of conditions.


Acute A quick one-time exposure to a chemical.


Adapter Device that adapts or changes one type of hose thread to another, allowing connection of two different lines. Adapters have a male end on one side and a female on the other with each side being a different thread type, for example, an iron pipe to national standard adapter.


Administrative Warrant An order issued by a magistrate that grants authority for fire personnel to enter private property for the purpose of conducting a fire prevention inspection.

Aerial Apparatus

Aerial Apparatus Fire apparatus using mounted ladders and other devices for reaching areas beyond the length of ground ladders.


Air Bill The term used to describe the shipping papers used in air transportation.

Aircraft Rescue and Firefighting (ARFF)

Aircraft Rescue and Firefighting (ARFF) Of or pertaining to firefighting operations involving fixed or rotary wing aircraft.

Air Monitoring Devices Used to determine oxygen, explosive, or toxic levels of gases in air.

Air-Purifying Respirator (APR)

Air-Purifying Respirator (APR) Respiratory protection that filters contaminants out of the air, using filter cartridges. Requires the atmosphere to have sufficient oxygen, in addition to other regulatory requirements.


Allergic Reaction The body’s reaction to a substance to which there is an allergy.


Americans with Disabilities Act Public law that bars discrimination on the basis of disability in state and local services. Enacted in 1990.


Amputation Occurs when part of the body is severed completely as a result of an injury.


Anchor Point A safe location from which to begin line construction on a wildland fire.


ANFO The acronym that is used for ammonium nitrate fuel oil mixture, which is a common explosive. ANFO was used in the Oklahoma City bombing incident.


Anthrax A biological material that is naturally occurring and is severely toxic to humans. It is commonly used in hoax incidents.


Application Rate Amount of foam or foam solution needed to extinguish a fire. Usually expressed in gallons per minute per square foot or liters per minute per square meter.

Aqueous Film-Forming Foam (AFFF)

Aqueous Film-Forming Foam (AFFF) A synthetic foam that as it breaks down forms an aqueous layer or film over a flammable liquid.


Aquifer A formation of permeable rock, gravel, or sand holding water or allowing water to flow through it.


Arson A malicious fire or fires set intentionally by humans for vengeance or profit.


Arterial Bleeding Bleeding from an artery.


Arteries The blood vessels, or tubes, within the body that carry blood rich with oxygen and nutrients away from the heart.

Articulating Boom Ladder

Articulating Boom Ladder An apparatus with a series of booms and a platform on the end. It is maneuvered into position by adjusting the various boom sections into place to position the platform at the desired location.


Aspect The direction a slope faces given in compass directions.


Asphyxiation Condition that causes death due to lack of oxygen and an excessive amount of carbon monoxide or other gases in the blood.


Association of Public Safety Communications Officials-Int., Inc. (APCO) International not-for-profit organization dedicated to the advancement of public safety communications. Membership is made up of public safety professionals from around the world.


Atmospheric Pressure The pressure exerted by the atmosphere, which for Earth is 14.7 pounds per square inch at sea level.


Atomization The separation of atoms and molecules into an unconnected state where they are in suspension rather than in liquid form.


Attack Hose Small- to large-diameter hose used to supply nozzles and other applicators or protective system for fire attack. Attack hose commonly means handheld hoselines from 11/2 to 21/2 inches (38 or 63 mm) in diameter.


Authority Having Jurisdiction (AHJ) The responsible governing organization or body having legal jurisdiction.


Autoextended When a fire goes out the window on one floor, up the side of the building, which is often noncombustible, and extends through the window or cockloft directly above.

Automated External Defibrillator (AED)

Automated External Defibrillator (AED) A portable computer-driven device that analyzes a patient’s heart rhythm and delivers defibrillation shocks when necessary.

Automatic or Constant Pressure Nozzle

Automatic or Constant Pressure Nozzle Nozzle with a spring mechanism built in that reacts to pressure changes and adjusts the flow and resultant reach of the nozzle.


Automatic Sprinkler System A system of devices that will activate when exposed to fire, connected to a piping system that will supply water to control the fire. Typically, an automatic sprinkler system is also supported by firefighters when they arrive on the scene.


Auxiliary Appliances Another term for protective devices, particularly sprinkler and standpipe systems.


Available Flow Amount of water that can be moved to extinguish the fire. Depends on the water supply, pump(s) and their capabilities, and the size and length of hose.


Avulsion An injury where a part of the skin is torn away, but still attached, leaving a flap or loose area hanging.


Awareness Level The basic level of training for emergency response to a chemical accident, the basis of which is the ability to recognize a hazardous situation and call for assistance.

Axial Load

Axial Load A load passing through the center of the mass of the supporting element, perpendicular to its cross section.


Backdraft A sudden, violent reignition of the contents of a closed container fire that has consumed the oxygen within the space when a new source of oxygen is introduced.


Backflow Preventers A check valve or set of valves used to prevent a backflow of water from one system into another. Required where a building water or fire protection system connects with the public water system. Backflow preventers are being required for environmental and health reasons.


Backstretch or Flying Stretch An attack line lay where the engine is at the hydrant and the line is stretched back from the engine to the fire. The flying stretch is a version of the backstretch where the engine stops in front of the fire, the attack portion is removed, and the engine proceeds to the hydrant.


Balloon Frame A style of wood frame construction in which studs are continuous for the full height of a building.


Bank Down A condition in which the heat, smoke, and fire gases have reached the uppermost level in a compartment and, instead of continuing up, begin to push down from the ceiling toward the floor.


Base Radio Radio station that contains all of the antennas, receivers, and transmitters necessary to transmit and receive messages.


Basic 9-1-1 Telephone system that automatically connects a person dialing the digits “9-1-1” to a predetermined answering point through normal telephone service facilities. Number and location information is not normally provided in basic systems.


Beam A structural member subjected to loads perpendicular to its length.


Bed Ladder The nonextending part of an extension ladder.


Bevel The outside curve of the fork end of the Halligan tool.


Bight A doubled section of rope, usually made along the standing part, that forms a U-turn in the rope that does not cross itself.


Biological Agents Microorganisms that cause disease in humans, plants, and animals; they also cause the victim’s health to deteriorate. Biological agents have been designed for warfare purposes.


Biomimetic A form of gas sensor that is used to determine levels of carbon monoxide. It is of the type of sensors used in home CO detectors. It closely re-creates the body’s reaction to CO and activates an alarm.


Blister Agents A group of chemical agents that cause blistering and irritation of the skin. Sometimes referred to as vesicants.


Blood Agents Chemicals that affect the body’s ability to use oxygen. If they prevent the body from using oxygen, fatalities result.


Body Substance Isolation Precautions A set of precautions for emergency responders designed to prevent exposure to any body fluid or substance.

Boiling Liquid Expanding Vapor Explosion (BLEVE)

Boiling Liquid Expanding Vapor Explosion (BLEVE) Describes the rupture of a container when a confined liquid boils and creates a vapor pressure that exceeds the container’s ability to hold it.


Boiling Point The temperature at which liquids must be heated in order to turn into a gas.


Bolt Throw The distance the bolt of a lock travels into the jamb or strike plate. Usually 1/2 to 11/2 inches.


Bond A substance or an agent that causes two or more objects or parts to bind.

Booster Hose

Booster Hose Smaller diameter, flexible hard-rubbercoated hose of 3/4- or 1-inch (19- to 25-mm) size usually mounted on a reel that can be used for small trash and grass fires or overhaul operations after the fire is out.

Bourdon GaugeBourdon Gauge

Bourdon Gauge The type of gauge found on most fire apparatus that operates by pressure in a curved tube moving an indicating needle.


Box Canyon A canyon open on one end and closed on the other. They become very dangerous when wildfire enters them.

Brachial Artery

Brachial Artery A major artery in the inside of the upper arm that supplies blood to the arm. Can be used as a pressure point for controlling bleeding and for locating a pulse on an infant.


Branch The command designation established to maintain span of control over a number of divisions, sectors, or groups.

Bresnan Distributor

Bresnan Distributor Has six or nine solid tips or broken stream openings designed to rotate in a circular spray pattern. Used to fight fire in basements or cellars when firefighters cannot make a direct attack on the fire.


British Thermal Unit (BTU) A measurement of heat that describes the amount of heat required to raise 1 pound of water 1°F.

Brush Gear

Brush GearAnother term for a wildland personal protective ensemble.


Building Officials Conference Association (BOCA) A group that establishes minimum building and fire safety standards.

Bulk Tanks

Bulk Tanks A large transportable tank, comparable to a tote, but considered to be the larger of the two.

Bump Test

Bump Test Used to determine if an air monitor is working. It will alarm if a toxic gas is present. It is a quick check to make sure the instrument responds to a sample of gas.


Bunkers A slang term that is used mostly to describe the components of a structural firefighting ensemble. The original use of the term bunkers referred only to the pant/boot combination that firefighters wore at night and placed next to their “bunks” for rapid donning.


Butyric Acid A fairly common lab acid that has been used in many attacks on abortion clinics. Although not extremely hazardous, it has a characteristic stench that permeates the entire area where it is spilled.

Bypass EductorBypass Eductor

Bypass Eductor Eductor with two waterways and a valve that allows plain water to pass by the venturi or through the venturi to create foam solution.


Calibration Used to set the air monitor and to ensure that it reads correctly. When calibrating a monitor, it is exposed to a known quantity of gas to make sure it reads the values correctly.


Cantilever Beam A beam that is supported at only one end.


Capillaries The very small blood vessels in the body that connect arteries and veins and filter the oxygen and nutrients from the blood into the tissues of the body.


Capillary Bleeding Bleeding from a capillary.


Carbon Dioxide (CO2) An inert colorless and odorless gas that is stored under pressure as a liquid that is capable of being self-expelled and is effective in smothering Class B and C fires.


Carbon Monoxide Colorless, odorless, poisonous gas that when inhaled combines with the red blood cells excluding oxygen.


Carcinogen A material that is capable of causing cancer in humans.

Cardiovascular System

Cardiovascular System The heart, blood vessels, and blood within the body.

Carotid Pulse

Carotid Pulse The pulse located on either side of the neck.

Catalytic Bead

Catalytic Bead The most common type of combustible gas sensor that uses two heated beads of metal to determine the presence of flammable gases.


Ceiling Level The highest exposure a person can receive without suffering any ill effects. It is combined with the PEL, TLV, or REL as a maximum exposure.

Cellar Nozzles

Cellar Nozzles Has four spray nozzles designed to rotate in a circular spray pattern for fighting fires in basements or cellars when firefighters cannot make a direct attack on the fire.


Chain of Command Common fire service term that means to always work through one’s direct supervisor. The fire service is viewed as a paramilitary organization and because of this all requests for information outside the assigned workplace should go through the supervisor.


Check Valves Valves installed to control water flow in one direction, typically when different systems are interconnected.


Chemical Burns Burns caused by chemical substances that come into contact with the skin or tissues of the body, creating a caustic reaction.


Chemtrec The Chemical Transportation Emergency Center, which provides technical assistance and guidance in the event of a chemical emergency; a network of chemical manufacturers who provide emergency information and response teams if necessary.


Chimney Another term for drainage. Given because of the draw of fire as in heat going up the chimney.

Chip Measurement System (CMS)

Chip Measurement System (CMS) A form of colorimetric air sampling in which the gas sample passes through a tube. If the correct color change occurs, the monitor interprets the amount of change and indicates a level of the gas on an LCD screen.


Choking Agents Agents that cause a person to cough and have difficulty breathing. The terrorism agents that are considered choking agents are chlorine and phosgene, both very toxic gases.


Chord The top and bottom components of a beam or truss. The top chord is subjected to compressive force; the bottom chord is subjected to tensile force.


Chronic A continual or repeated exposure to a hazardous material.


Cistern An underground water tank made from natural rock or concrete. Cisterns store large quantities of water—30,000 gallons or more—in areas without other water supplies or as a backup supply.


Clandestine Drug Labs Illegal labs set up to manufacture street drugs.


Class A Classification of fire involving ordinary combustibles such as wood, paper, cloth, plastics, and rubber.


Class B Classification of fire involving flammable and combustible liquids, gases, and greases. Common products are gasoline, oils, alcohol, propane, and cooking oils.


Class C Classification of fire involving energized electrical equipment, which eliminates using waterbased agents.


Class D Classification of fire involving combustible metals and alloys such as magnesium, sodium, lithium, and potassium.

Class K

Class K A new classification of fire as of 1998 that involves fires in combustible cooking fuels such as vegetable or animal oils and fats.


Clipping Term associated with the use of two-way radios that is used to describe instances when either the first part of a message or the last part of a message is cut off as the result of either speaking before pressing the transmit key or releasing the transmit key prior to the end of a transmission.


Closed-Circuit SCBA A type of SCBA unit in which the exhaled air remains in the system to be filtered and mixed with oxygen for reuse.


Cockloft The area between the roof and the ceiling.


Code of Federal Regulations(CFR) The documents that include federally promulgated regulations for all federal agencies.

Collapse Zone

Collapse Zone The area around a building where debris will land when it falls. As an absolute minimum this distance must be at least 11/2 times the height of the building.

Colorimetric Tubes

Colorimetric Tubes Crystal-filled tubes that change colors in the presence of the intended gases. These tubes are made for the detection of known and unknown gases.


Column A structural element that is subjected to compressive forces—typically a vertical member.


Combination Attack A combined attack based on partial use of both offensive and defensive attack modes.

Combination Fire Attack

Combination Fire Attack A blend of the direct and indirect fire attack methods, with firefighters applying water to both the fuel and the atmosphere of the room.

Combination Nozzle

Combination Nozzle A spray nozzle that is capable of providing straight stream and spray patterns, which are adjustable or variable by the operator. Most fog nozzles used today are combination nozzles.


Combustion The chemical action in which heat and light are produced and the heat is used to maintain the chemical chain reaction to continue the process.


Command Vehicle Typically used by operations chief officers in the fire service.


Common Terminology The designation of a term that is the same throughout an IMS.


Communicable Disease A disease that can be transmitted from one person to another.


Communications Sending, giving, or exchanging of information.


Company A team of firefighters with apparatus assigned to perform a specific function in a designated response area.


Compound A combination of substances joined in a chemical bond that exists in a proportional amount and cannot be separated without chemical interaction.

Compressed Air Foam Systems (CAFS)Compressed Air Foam Systems (CAFS)

Compressed Air Foam Systems (CAFS) A foam system where compressed air is injected into the foam solution prior to entering any hoselines. The fluffy foam created needs no further aspiration of air by the nozzle.


Compression A force that tends to push materials together.

Computer-Aided Dispatch

Computer-Aided Dispatch Computer-based automated system that assists the telecommunicator in assessing dispatch information and recommends responses.


Computer-Aided Management for Emergency Operations (CAMEO) Program A computer program that combines a chemical information database with emergency planning software. It is commonly used by HAZMAT teams to determine chemical information.

Concentrated Load

Concentrated Load A load applied to a small area.


Confined Space A space that is large enough to be entered but is not designed for continuous occupancy.


Conflagration A large and destructive fire.


Consent The acceptance of emergency medical treatment by a patient or victim.


Consist The shipping papers that list the cargo of a train. The listing is by railcar, and the consist lists all of the cars.


Consolidated Incident Action Plan The strategic goals to eliminate the hazard or control the incident.


Constant or Set Volume Nozzle Nozzle with one set volume at a set pressure. For example, 60 gpm at 100 psi (227 L/min 690 kPa). The only adjustment is the pattern.


Constricted A condition of the pupils where they are much smaller than normal and may appear almost like a "pinpoint".


Continuous Beam A beam that is supported in three or more places.


Control Room A room on the ground floor of a highrise building where all building systems controls are located.


Cribbing The use of various dimensions of lumber arranged in systematic stacks (pyramid, box, step, etc.) to support an unstable load.


Critical Incident Stress Debriefing(CISD) A formal gathering of incident responders to help defuse and address stress from a given incident.


Critical Incident Stress Management (CISM) A process for managing the short- and long-term effects of critical incident stress reactions.


Cryogenic Gas Any gas that exists as a liquid at a very cold temperature, always below 150°F.

Cutting Tools

Cutting Tools The group of tools used to cut through or around materials.


Damming The stopping of a body of water, which at the same time stops the spread of the spilled material.


Dangerous Cargo Manifest (DCM) The shipping papers for a ship, which lists the hazardous materials on board.


Database Organized collection of similar facts.


Dead Load The weight of the building materials and any part of the building permanently attached or built-in.


DECIDE Process A management system used to organize the response to a chemical incident. The factors of DECIDE are detect, estimate, choose, identify, do the best, and evaluate.


Decontamination The physical removal of contaminants (chemicals) from people, equipment, or the environment. Most often used to describe the process of cleaning to remove chemicals from a person.


Defensive Attack A calculated attack on part of a problem or situation in an effort to hold ground until sufficient resources are available to convert to an offensive form of attack.


Deflagrates Rapid burning, which in reality with regard to explosions can be considered a slow explosion, but is traveling at a lesser speed than a detonation.


Dehydration A loss of water and vital fluids in the body.

Deluge Systems

Deluge Systems Designed to protect areas that may have a fast-spreading fire engulfing the entire area. All of its sprinkler heads are already open, and the piping contains atmospheric air. When the system operates, water flows to all heads, allowing total coverage. The system uses a deluge valve that opens when a separate fire detection system senses the fire and signals to trip the valve open.


Density The mass per unit volume of a substance under specified conditions of pressure and temperature.

Deployment Plan

Deployment Plan Predetermined response plan of apparatus and personnel for specific types of incidents and specific locations.

Depth of Char

Depth of Char A term commonly used by fire investigators to describe the amount of time wooden material had burned. The deeper the char, the longer the material was burning or exposed to direct flame.


Design Load A load the engineer planned for or anticipated in the structural design.


Detergent-Type Foams Use synthetic surfactants to break down the surface tension of water to create a foaming blanket.


Diffusion A naturally occurring event in which molecules travel from levels of high concentration to areas of low concentration.


Diking A defensive method of stopping a spill. A common dike is constructed of dirt or sand and is used to hold a spilled product. In some facilities, a dike may be preconstructed such as around a tank farm.


Dilated A condition of the pupils where they are much larger than normal and can take up almost the whole colored portion of the eye.


Dilution The addition of a material to the spilled material to make it less hazardous. In most cases water is used to dilute a spilled material, although other chemicals could be used.

Direct Fire Attack

Direct Fire Attack An attack on the fire made by aiming the flow of water directly at the material on fire.


Disassembly The actual taking apart of vehicle components.


Discharge Flow Total amount of water flowing from the discharge side of the pump.


Displacement The relocating of major parts (i.e., doors, roof, dash, steering column) of a vehicle.


Distortion The bending of sheet metal or components.

Distributed Load

Distributed Load A load applied equally over a broad area.


Distributor Pipe or Extension Pipe Devices that allow a nozzle or other device to be directed into holes to reach basements, attic, and floors that cannot be accessed by personnel. The distributor pipe has self-supporting brackets that help hold it into place when in use.


Diverting Using materials to divert a spill around an item. For instance, several shovels full of dirt can be used to divert a running spill around a storm drain.


Division Command designation responsible for operations within an assigned geographic area.


Double Female Allows the two male ends of hose to be connected.


Double Male Used to connect two female thread couplings.


Drafting The pumping of water from a static source by taking advantage of atmospheric pressure to force water from the source into the pump.


Drainage A topographic feature on the side of a hill or mountain that naturally collects water runoff, channeling it to the bottom of the rise. Fire is attracted to this feature.


Dressing The practice of making sure that all parts of a knot are lying in the proper orientation to the other parts and look exactly as the pictures herein indicate.


Dry Chemicals Dry extinguishing agents divided into two categories. Regular dry chemicals work on Class B and C fires; multipurpose dry chemicals work on Class A, B, and C fires.

Dry HydrantDry Hydrant

Dry Hydrant A piping system for drafting from a static water source with a fire department connection at one end and a strainer at the water end.

Dry Pipe System

Dry Pipe System Air under pressure replaces the water in the system to protect against freezing temperatures. The sprinkler control valve uses a dry pipe valve to keep pressurized air maintained above with the supply water under pressure below the valve.


Dry Powders Extinguishing agents for Class D fires.

Dump Site

Dump Site The area where tenders are unloaded or their load dumped.


Dutchman A short fold of hose or a reverse fold that is used when loading hose and a coupling comes at a point where a fold should take place or when two sets of couplings end up on top of or next to each other. The dutchman moves the coupling to another point in the load.


Dynamic A rope having a high degree of elongation (10 to 15 percent) at normal safe working loads.


Ears Elongated folds or flaps at the ends of a layer of hose to assist in pulling that layer.

Eccentric Load

Eccentric Load A load perpendicular to the cross section of the supporting element that does not pass through the center of mass.


Eductor Device that siphons a liquid from a container into a moving stream.


8-Step Process A management system used to organize the response to a chemical incident. The elements are site management and control, identifying the problem, hazard and risk evaluation, selecting PPE and equipment, information management and resource coordination, implementing response objectives, decon and cleanup operations, and terminating the incident.


Electrical Conductor Any material that will permit electricity to flow through it.

Emergency Call Box

Emergency Call Box System of telephones connected by private line telephone, radio-frequency, or cellular technology usually located in remote areas and used to report emergency situations.

Emergency Communications Center

Emergency Communications Center Facility either wholly or partially dedicated to being able to receive emergency and, in some instances, nonemergency reports from citizens. Centers such as these are sometimes referred to as fire alarm, headquarters, dispatch, or a public safety answering point (PSAP).

Emergency Decon

Emergency Decon The rapid removal of a material from a person when that person (or responder) has become contaminated and needs immediate cleaning. Most emergency decon setups use a single hoseline to perform a quick gross decon of a person with water.


Emergency Medical Dispatch System designed for use by telecommunicators to assist them in evaluating patient symptoms using predetermined criteria and responses.


Emergency Medical Services The delivery of prehospital medical treatment.

Emergency Medical Technician (EMT)

Emergency Medical Technician (EMT) An individual trained and certified to provide basic life support emergency medical care.


Emergency Planning and Community Right to Know Act (EPCRA) The portion of SARA that specifically outlines how industries report their chemical inventory to the community.

Emergency Response Guidebook (ERG)

Emergency Response Guidebook (ERG) Book provided by the DOT that assists the first responder in making decisions at a transportation-related chemical incident.


Emergency Response Planning (ERP) Levels that are used for planning purposes and are usually associated with the preplanning for evacuation zones.


Employee Assistance Program (EAP) A defined program that offers professional mental health and other health services to employees.

Encapsulated Suit

Encapsulated Suit A chemical suit that covers the responder, including the breathing apparatus. Usually associated with Level A clothing, that is gasand liquid tight, but there are some Level B styles that are fully encapsulated, but not gas- or liquid tight.


Encoder Device that converts an “entered” code into paging codes, which in turn activate a variety of paging devices.

Endothermic Reaction

Endothermic Reaction A chemical reaction in which heat is absorbed, and the resulting mixture is cold.

Engine Company

Engine Company The unit designation of a group of firefighters assigned to a piece of apparatus designed to deliver water to the fire scene.


Engulfed To swallow up or overwhelm.


Enhanced 9-1-1 Similar in nature to basic 9-1-1 but with the capability to provide the caller’s telephone number and address.


Equilibrium When referring to gas or liquids, a state where a balance has occurred in mixture or weight.


Etiological A form of a hazard that includes biological, viral, and other disease-causing materials.


Evacuation The movement of people from an area, usually their homes, to another area that is considered to be safe. People are evacuated when they are no longer safe in their current area.


Evaporation A process in which the molecules of a liquid are liberated into the atmosphere at a rate greater than the rate at which the molecules return to the liquid. Ultimately the liquid becomes fully airborne in a gaseous state.


Exhauster A device to speed the operation of the dry pipe valve by detecting the decrease in air pressure. It helps bleed off air.


Exit Drills in the Home (EDITH) A fire survival program to encourage people to practice fire drills from their home or residence.

Exothermic Reaction

Exothermic Reaction A chemical reaction that releases heat, such as when two chemicals are mixed and the resulting mixture is hot.


Explosive Limits A concentration of a gas or liquid that is not too rich or too lean to ignite with force.


Exposure A contact with a potentially disease-producing organism; the contact does not necessarily produce the disease in the exposed individual.


Exposure Fire Any combustible item threatened by something burning nearby that has caught on fire.

Extension Ladder

Extension Ladder A ladder consisting of two or more sections that has the ability to be extended to a desired height through the use of a halyard.


External Bleeding Bleeding that is coming from an open wound on the body.


External Floating Roof Tank Tank with the roof exposed on the outside that covers the liquid within the tank. The roof floats on the top of the liquid, which does not allow for vapors to build up.


Extremely Hazardous Substances (EHS) A list of 366 substances that the EPA has determined present an extreme risk to the community if released.


Extricate To set free, release, or disentangle a patient from an entrapment situation.


Federal Communications Commission Government agency charged with administering the provisions of the Communications Act of 1934 and the revised Telecommunications Act of 1996 and is responsible for nonfederal radio-frequency users.


Femoral Artery A major artery in the lower body near the groin that supplies the leg with blood. Can be used as a pressure point for controlling bleeding in the lower extremities.

Fill Site

Fill Site The area where tenders are filled or get their water.

Fine Decon

Fine Decon The most detailed of the types of decontamination. Usually performed at a hospital that has trained staff and is equipped to perform fine decon procedures.


Fire Alarm Notification to the fire department that a fire or other related emergency is in progess, which results in a response.


Fire Engineering The study of fire, fire behavior, fire extinguishment, and suppression.


Fire Flow Capacity The amount of water available or amount that the water distribution system is capable of flowing.


Fire Flow Requirement A measure comparing the amount of heat the fire is capable of generating versus the amount of water required for cooling the fuels below their ignition temperature.


Fire Hazard Any condition, situation, or operation that could lead to the ignition of unwanted combustion or result in proper combustion becoming uncontrolled.

Fire Hose

Fire Hose A flexible conduit used to convey water or other agent from a water source to the fire.


Fire Hydraulics The principles associated with the storage and transfer of water in firefighting activities.


Fire Intensity A measurement of Btus produced by a fire. Sometimes measured in flame length in the wildland environment.


Fire Load The amount of heat energy released when combustibles burn in a given area or building— expressed in British thermal units (Btus).


Fire Resistive The capacity of a material to withstand the effects of fire.


Fire-Resistive Rating The time in hours that a material or assembly can withstand fire exposure. Fireresistive ratings are usually provided for testing organizations. The ratings are expressed in a time frame, usually hours or portions thereof.

Fire ShelterFire Shelter

Fire Shelter A last-resort protective device for wildland firefighters caught or trapped in an environment where a firestorm or blowup is imminent.


Fire Societies Groups of people who voluntarily banded together to deal with a community’s fire problems.

Fire Station Alerting System

Fire Station Alerting System System used to transmit emergency response information to fire station personnel via voice and/or digital transmissions.


Fire Stopping Pieces of material, usually wood or masonry, placed in stud or joist channels to slow the extension of fire.

Fire Stream

Fire Stream The water or other agent as it leaves the hose and nozzle toward its objective, usually the fire.

Fire Tetrahedron

Fire Tetrahedron Four-sided pyramid-like figure describing the heat, fuel, oxygen, and chemical reaction necessary for combustion.


Fire Wardens Designated community individuals who walked the streets at night looking for fire and carrying large wooden rattles with which to signify a found fire.


Fire Watch An organized patrol of a protected property when the sprinkler or other protection system is down for maintenance. Personnel from the property regularly check to make sure a fire has not started and assist in evacuation and prompt notification of the fire department.


Firefighter Assist and Search Team (FAST) A company designated to search for and rescue trapped or lost firefighters. May also be called a rapid intervention team (RIT).


Firemark Signs on sheets of metal telling firefighters which company held the insurance policy on a home or building.


First Responders A group designated by the community as those who may be the first to arrive at a chemical incident. This group is usually composed of police officers, EMS providers, and firefighters.


Fit Testing A test that ensures the respiratory protection fits the face and offers maximum protection.


Flammable Limits The concentration level of a substance at which it will burn.


Flammable Range Ratio of gas to air that will sustain fire if exposed to flame or spark.


Flanks of the Fire The sides of a wildland fire running from the start point up each side to the end of the fire running into unburned areas.


Flash Point The temperature at which a liquid will liberate a flammable gas.


Flashover A sudden event that occurs when all the contents of a container reach their ignition temperature simultaneously.


Flow The rate or quantity of water delivered, usually measured in gallons per minute or liters per minute (1 gpm 3.785 L/min).


Fluoroprotein Film-Forming Foam (FFFP) Combines protein with the film-forming fluorinated surfactants of AFFF to improve on the qualities of both types of foam.


Fluoroprotein Foam Designed as an improved protein foam with a fluorinated surfactant added.

Flush or Slab Doors

Flush or Slab Doors Doors that are flat or have a smooth surface and may be of either hollow-core or solid-core construction.

Fly Ladder

Fly Ladder That portion of a ladder that extends out from the bed ladder. Also called fly section.


Foam An aggregate of gas-filled bubbles formed from aqueous solutions of specially formulated concentrated liquid foaming agents.

Fog NozzleFog Nozzle

Fog Nozzle Delivers either a fixed spray pattern or variable combination of straight stream and spray patterns.


Forcible Entry The fire scene task of gaining entry to a building or secured area by disabling, breaking, or going around locking and security devices.


Foreman Individual designated as the leader of an early fire company; a predecessor to the modern title of fire chief.

Forestry Hose

Forestry Hose Specially designed hose for use in forestry and wildland firefighting. It comes in 1- and 11/2-inch (25- and 38-mm) sizes and should meet U.S. Forestry Service specifications.

Formal Decon

Formal Decon The washing and scrubbing portion of the decontamination process. The process is usually repeated and is performed by a decon crew.


Fracture A medical term for a broken or cracked bone in the body.


Frangible Disk A type of pressure-relieving device that actually ruptures in order to vent the excess pressure. Once opened the disk remains open; it does not close after the pressure is released.


Freelancing The act of working alone or performing a task for which the firefighter has not been assigned.

Freezing Point

Freezing Point The temperature at which liquids become solids.


Friction Caused by the rubbing of materials against each other while in movement and converts or robs some of the movement energy into heat energy.


Friction Loss Measurement of friction in a system such as a hoseline.


Frontage The portion of a property that faces and actually touches the street.


Fuel Resistance Ability to tolerate the fuel and to avoid being saturated by or picking up the fuel.

Full-Thickness Burns

Full-Thickness Burns Burns affecting not only the skin structure but the tissues and muscles underneath. Full thickness burns may be red, white, or charred in color, and will appear dry because the blood vessels in the skin are damaged extensively and are not supplying fluids to the area.


Garden Apartment A two- or three-story apartment building with common entryways and layouts on each floor, surrounded by greenery and landscaping, sometimes having porches and patios.


Gas A state of matter that describes the material in a form that moves freely about and is difficult to control. Steam is an example.


Gate Valves Indicating and nonindicating valves that are opened and closed to control water flow.


Gauge Pressure Measures pressure without atmospheric pressure. Normally fire department gauges do not measure atmospheric pressure. Gauge pressure is measured in psi or psig.


GEDAPER Process A management system used to organize the response to a chemical incident. The factors are gather information, estimate potential, determine goals, assess tactical options, plan, evaluate, and review.


Girder A large structural member used to support beams or joists—that is, a beam that supports beams.


Glazing The glass or other clear material portion of the window that allows light to enter.

Gross Decon

Gross Decon The portion of the decontamination process that removes the majority of the chemicals through a flushing process. The gross washing is done using large amounts of water and is usually done by the individual or the individual’s partner.


Gross Negligence Occurs when an individual disregards training and continues to act in a manner without regard for others.


Ground Pads Sheets of plywood, planks, aluminum sheets, and so on, used to distribute weight over a larger area.


Guard Dogs Trained animals that will attack an intruder.


Guideline/Lifeline Rope used as a crew is searching a structure to assist them in finding their way back out.

Gusset Plate

Gusset Plate A connecting plate used in truss construction. In steel trusses, these plates are flat steel stock. In wood trusses, the plates are either lightgauge metal or plywood.

Halligan Tool

Halligan Tool From the prying group, a 30-inch forged steel tool with three primary parts: the adz end, the pike end, and the fork end.


Halyard A rope or cable that is used to raise the fly ladders of an extension ladder.

Hard Suction Hose

Hard Suction Hose A special type of hose that does not collapse when used for drafting.


Hardware Equipment used in conjunction with life safety ropes and harnesses (carabiners, figure eights, rappel racks, etc.).


Harnesses Webbing sewn together to form a belt, seat harness, or seat and chest harness combination.

Hazardous Materials

Hazardous Materials Chemicals that are flammable, explosive, or otherwise capable of causing death or destruction when improperly handled or released.

Hazardous Materials Technician

Hazardous Materials Technician An individual trained to meet the requirements of CFR OSHA 1910.120, Technician Level for Hazardous Materials Response.


Hazardous Waste Operations and Emergency Response (HAZWOPER) The OSHA regulation that covers safety and health issues at hazardous waste sites, as well as response to chemical incidents.


HAZMAT Crime A criminal act that uses or threatens the use of chemicals as a weapon.


Head of the Fire The running top or aggressive end of the fire away from the start point.


Head Pressure Measures the pressure of a column of water in feet (meters). Head pressure gain or loss results when water is being pumped above or below the level of the pump. A head of 2.31 feet (0.7 m) would equal 1 psi (6.895 kPa).


Heat Resistance The ability of foam to stand up to the heat of the fire or to hot surfaces near the fire.


Heat Sink The term used to denote a place where heat is drained away from a source.


Helix The metal or plastic bands or rings used in hard suction hose to prevent its collapse under drafting conditions.

Higbee Cut

Higbee Cut The blunt ending of the threads of fire hose couplings that allows the threads to be properly matched, avoiding cross-threading.


Hoistway The shaft in which an elevator or a number of elevators travel.

Hollow-Core Door

Hollow-Core Door Any door that is not solid, usually with some type of filler material between face panels.

Home Alerting Devices

Home Alerting Devices Emergency alerting devices primarily used by volunteer department personnel to receive reports of emergency incidents.


Hook A tool with a 32-inch to 12-foot handle with a pike and hook on one end. Used for pulling ceilings or separating other materials. Also known as a pike pole.


Horizontal Ventilation Channeled pathway for fire ventilation via horizontal openings.

Hose Bed

Hose Bed The portion or compartment of fire apparatus that carries the hose.

Hose Bridges

Hose Bridges Devices that allow vehicles to pass over a section of hose without damaging it.


Hose Cap Does not allow water to flow through it. Instead, it caps the end of a hoseline or appliance to prevent water flow.


Hose Cart A handcart or flat cart modified to be able to carry hose and other equipment around large buildings. Some departments use them for high-rise situations.

Hose Clamp

Hose Clamp A device to control the flow of water by squeezing or clamping the hose shut. Some work by pushing a lever that closes the jaws of the device and others have a screw mechanism or hydraulic pump that closes the jaws.


Hose Jackets Metal or leather devices used for stopping leaks without shutting down the line that is fitted over the leaking area and either clamped or strapped together to control the leak.


Hose Roller or Hoist A metal frame, with a securing rope, shaped to fit over a windowsill or edge of a roof with two rollers to allow the hose to roll over the edge, preventing chafe.


Hose Strap A short strap with a forged handle and cinch clip attached. Used to help maneuver hose and attach hose to ladders and stair rails.


HVAC Acronym for heating, ventilation, and airconditioning unit. HVACs are typically a rooftop unit on commercial buildings. Buildings may have one or dozens of these units.


Hydrant Valves or Switch Valves Valve used on a hydrant that allows an engine to connect and charge its supply line immediately but also allows an additional engine to connect to the same hydrant without shutting down the hydrant, and increases the flow of the hydrant.

Hydrant Wrenches

Hydrant Wrenches Tools used to operate the valves on a hydrant. May also be used as a spanner wrench. Some are plain wrenches and others have a ratchet feature to speed the operation of the valve.

Hydraulic Pistons

Hydraulic Pistons Mechanical rams that operate by pressure exerted through the use of a liquid, usually some form of oil.


Hydraulics The study of fluids at rest and in motion.


Hydrocarbon Any of numerous organic compounds, such as benzene and methane, that contain only carbon and hydrogen.


Hyperbaric Chamber A chamber that is usually used to treat scuba divers who ascended too quickly and need extra oxygen to survive. The chamber re-creates the high-pressure atmosphere of diving and forces oxygen into the body. It is also successful in the treating of carbon monoxide poisoning and smoke inhalation, because both of these problems require high amounts of oxygen to assist with the patient’s recovery.


Hypoperfusion A serious condition caused by a problem or failure of the circulatory system that results in a decrease of oxygen and vital nutrients to the body’s tissues. Also known as shock.


Hypoxia A deficiency of oxygen.


ICt50 The incapacitating level for time to 50 percent of the exposed group. It is a military term that is often used in conjunction with LCt50.


Ignition The point at which the need for outside heat application ceases and a material sustains combustion based on its own generation of heat.


Ignition Point The temperature at which a substance will continue to burn after the source is removed.


Ignition Temperature The temperature of a liquid at which it will ignite on its own without an ignition source. Can be compared to SADT.


Immediately Dangerous to Life and Health (IDLH)The maximum level of danger one could be exposed to and still escape without experiencing any effects that may impair escape or cause irreversible health effects.

Impact Load

Impact Load A load that is in motion when it is applied.


Implied Consent The assumption of acceptance of emergency medical treatment by an unconscious patient or a child with no parents or legal guardians present.


Incendiary Agents Chemicals that are used to start fires, the most common being a Molotov cocktail.


Incident Action Plan (IAP) A strategic and tactical plan developed by the incident commander.


Incident Commander Level A training level that encompasses the operations level with the addition of incident command training. Intended to be the person who may command a chemical incident.

Incident Management System (IMS)

Incident Management System (IMS) A management system utilized on the emergency scene that is designed to keep order and follow a sequence of set guidelines.


Incision A cut to the skin that leaves a straight, even pattern.


Increaser Used to connect a smaller hose to a larger one.

Indirect Fire Attack

Indirect Fire Attack An attack made on interior fires by applying a fog stream into a closed room or compartment, thus converting the water into steam to extinguish the fire.


Infection Control Procedures and practices for firefighters and emergency medical care providers to follow to prevent the transmission of diseases and germs from a patient to themselves or other patients.


Infectious Disease See See Communicable Disease. .

Infrared Sensor

Infrared Sensor A sensor that uses infrared light to determine the presence of flammable gases. The light is emitted in the sensor housing and the gas passes through the light. If it is flammable the sensor will indicate the presence of the gas.


Initial Assessment The initial investigative action taken by care providers to determine if the patient has the basic signs of life as well as any serious, lifethreatening injuries.

In-Line EductorIn-Line Eductor

In-Line Eductor Eductor in which the waterway is always piped through a venturi.


Inorganic A substance that is not of any living organism.


Intake Relief Valve Required on large-diameter hose at the receiving engine that functions as a combined overpressurization relief valve, a gate valve, and an air bleed-off.


Integrated Communications The ability of all units or agencies to communicate at an incident.


Interface Firefighting Fighting wildland fire and protecting exposed structures in rural settings.


Intermodel Containers These are constructed in a fashion so that they can be transported by highway, rail, or ship. Intermodal containers exist for solids, liquids, and gases.


Internal Bleeding Bleeding within the body when no visible open wound is present.


Internal Floating Roof Tank Tank with a roof that floats on the surface of the stored liquid, but also has a cover on top of the tank, so as to protect the top of the floating roof.


Intervention The act of intervening; to come between as an influencing force. Typically a reactive action.


Irons The combination of a Halligan tool and flathead ax or maul.


Irritant A material that is irritating to humans, but usually does not cause any long-term adverse health effects.


Isolation Area An area that is set up by responders and is intended to keep people, both citizens and responders, out. May later become the hot zone/sector as the incident evolves. Is the minimum area that should be established at any chemical spill.


Jacket The outer part of the hose, often a woven cloth or rubberized material, which protects the hose from mechanical and other damage.


Jamb The mounting frame for a door.


Jet Dump A device that speeds the process of dumping a load of water from a tanker/tender.

Jet Siphon

Jet Siphon A device that speeds the process of transferring water from one tank to another.


Joist A wood framing member that supports floor or roof decking.


Kerf Cut A quick and easily made examination hole. It is created by letting the spinning blade of a power saw cut through the material to be cut and pulling it out, leaving only a slit-like cut measuring approximately 12 inches long and only as wide as the cutting blade.

Kern Kern A derivative of the term kernel, which is defined as “the central, most important part of something; core; essence.”

Knockdown Speed Speed with which foam spreads across the surface of a fuel.


Laceration A cut to the skin and underlying tissues that leaves an irregular, even pattern.

Ladder Pipe

Ladder Pipe An appliance that is attached to the underside of an aerial ladder for an elevated water application.


Laminated Glass Glass composed of two or more sheets of glass with a plastic sheet between them. The purpose of the plastic sheet is to hold the glass together if broken, thus reducing the hazard of flying glass.


Landing Plate The plate at the top or bottom of an escalator where the steps disappear into the floor.


Laws Legislation that is passed by the House and Senate and signed by the president.


LCt50 The lethal concentration for time to 50 percent of the group. Same as the LC50, but adds the element of time. It is a military term.


Leaking Underground Storage Tank (LUST) Describes a leaking tank that is underground.


Ledge Door Door built with solid material, usually individual boards, common in barns and warehouses.


Lethal Concentration (LC50) A value for gases that provides the amount of chemical that could kill 50 percent of the exposed group.


Lethal Dose (LD50) A value for solids and liquids that provides the amount of a chemical that could kill 50 percent of an exposed group.

Level A Protective Clothing

Level A Protective Clothing Fully ecapsulated chemical protective clothing. It is gas and liquid tight and offers protection against chemical attack.


Level B Protective Clothing A level of protective clothing that is usually associated with splash protection. Level B requires the use of SCBA. Various clothing styles are considered Level B.


Liability The possibility of being held responsible for individual actions.


Life Safety Term applied to the fire protection concept in which buildings are designed to allow for the escape of building occupants without injuries. Life safety usually makes the building more fire resistant, but this is not the main goal.


Life Safety Line According to NFPA 1983, rope dedicated solely to the purpose of constructing lines for supporting people during rescue, firefighting, or other emergency operations, or during training evolutions.


Lifting A term used to describe the removal of upperlevel smoke and heat when cool air replaces the upper-level hot air that is escaping.


Liner The inner layer of fire hose, usually made of rubber or a plastic material, that keeps the water in the tubing of the hose.


Lintel A beam that spans an opening in a load-bearing masonry wall.


Liquid A state of matter that implies fluidity, which means a material has the ability to move as water would. There are varying states of being a liquid from moving very quickly to moving very slowly. Water is an example.


Live Load The weight of all materials and people associated with but not part of a structure.


Load-Bearing Wall Any wall that supports other walls, floors, or roofs.


Loaded Stream Combats the water freezing problem by adding an alkali salt as an antifreezing agent.


Loading The weight of building materials or objects in a building.


Local Application System Designed to protect only a certain or local portion of the building, usually directly where the hazard will occur or spread.


Local Emergency Planning Committe (LEPC) A group composed of members of the community, industry, and emergency responders to plan for a chemical incident, and to ensure that local resources are adequate to handle an incident.


Locking Devices A mechanical device or mechanism used to secure a door or window.


Loop A turn in the standing part that crosses itself and results in the standing part continuing on in the original direction of travel.


Lower Explosive Limit (LEL) The lower part of the flammable range, and is the minimum required to have a fire or explosion.


Mantle Anything that cloaks, envelops, covers, or conceals.


Mask Confidence or "Smoke Divers" Training Training courses designed to develop a firefighter’s skills and confidence for using SCBA.


Mass Casualty An incident in which the number of patients exceeds the capability of the EMS to manage the incident effectively. In some jurisdictions this can be two patients, while in others it may take ten to make the incident a mass casualty.

Master Stream or Heavy Appliances

Master Stream or Heavy Appliances Non-handheld water applicator capable of flowing over 350 gallons of water per minute (1325L/min).


Mastery The concept that an individual can achieve 90 percent of an objective 90 percent of the time.

Material Safety Data Sheets (MSDS)

Material Safety Data Sheets (MSDS) Information sheet for employees that provides specific information about a chemical, with attention to health effects, handling, and emergency procedures.


Matter Something that occupies space and can be perceived by one or more senses; a physical body, a physical substance, or the universe as a whole. Something that has mass and exists as a solid, liquid, or gas.


Mayday A universal call for help. A Mayday indicates that an individual or team is in extreme danger.


Means of Egress A safe and continuous path of travel from any point in a structure leading to a public way. Composed of three parts: the exit access, the exit, and the exit discharge.


Medium-Diameter Hose (MDH) Either 21/2- or 3-inch (63- or 75-mm) hose.


Medi-vac An ambulance that transports patients by air. Typically, medi-vac units are helicopters with highly trained EMS personnel and nurses.

Melting Point

Melting Point The temperature at which solids become liquids.

Metal Oxide Sensor

Metal Oxide Sensor A coiled piece of wire that is heated to determine the presence of flammable gases.


Midslope An area partway up a slope. Any location not on the bottom or top of a slope, as in a midslope road crossing the slope horizontally.


Miscible Having the ability to mix with water.


Mission Statement A written declaration by a fire agency describing the things that it intends to do to protect its citizenry or customers.


Mission Vision A term used to describe a condition in which a person becomes so focused on an objective that peripheral conditions are not noticed, as if the person is wearing blinders.


Mitigation Actions taken to eliminate a hazard or make a hazard less severe or less likely to cause harm. Typically a proactive action.

Mobile Data Computer

Mobile Data Computer Communication device that, unlike the mobile data terminal, does have information processing capabilities.

Mobile Data Terminal

Mobile Data Terminal Communications device that in most cases has no information processing capabilities.


Mobile Radio Complete receiver/transmitter unit that is designed for use in a vehicle.

Mobile Support Vehicle

Mobile Support Vehicle Vehicle designed exclusively for use as an on-scene communication center and command post.


Modular Organization The ability to start small and expand if an incident becomes more complex.


Molecule The smallest particle into which an element or a compound can be divided without changing its chemical and physical properties; a group of like or different atoms held together by chemical forces.


Mortar Mixture of sand, lime, and portland cement used as a bonding material in masonry construction.


Mounting Hardware Hinges, tracks, or other means of attaching a door to the frame or jamb.

Multigas Detector

Multigas Detector A term used to describe an air monitor that measures oxygen levels, explosive (flammable) levels, and one or two toxic gases such as carbon monoxide or hydrogen sulfide.


Multiple-Alarm Incident Involves the response of additional personnel.


Mutual Aid or Assistance Agreements Prearranged written agreements of the type and amount of assistance one jurisdiction will provide to another in the event of a large-scale fire or disaster. The key to understanding mutual aid is that it is a reciprocal agreement.


National Emergency Number Association Not-forprofit organization founded in 1982 and made up of more than 6,000 members. The association fosters technical advancement, availability, and implementation of a universal emergency telephone number system.


National Fire Protection Association (NFPA) A notfor- profit membership organization that uses a consensus process to develop model fire prevention codes and firefighting training standards.


National Institute for Occupational Safety and Health (NIOSH) A federal institute tasked with investigating firefighter fatalities and making recommendations to prevent reoccurrence.


National Response Center (NRC) The location that must be called to report a spill if it is in excess of the reportable quantity.


Needed or Required Flow Estimate of the amount of water required to extinguish a fire in a certain type period. Based on the type and amount of fuel burning.


Negligence Acting in an irresponsible manner or different from the way in which someone was trained; that is, differing from the standard of care.


Nerve Agents Chemicals that are designed to kill humans, specifically in warfare. They are chemically similar to organophosphorus pesticides and cause the same medical reaction in humans.


Nested The state when all the ladders of an extension ladder are unextended.

NFPA 1001 Standard for Fire Fighter Professional Qualifications, a national consensus training standard establishing the job performance requirements of tasks to be performed by firefighters.


NFPA 1404 National Fire Protection Association standard created by the Fire Service Training Committee detailing the requirements for fire service SCBA programs, including training and maintenance procedures.


NFPA 1500 National Fire Protection Association standard created by the Technical Committee on Fire Service Occupational Safety and Health that addresses a number of issues concerning protective equipment.


NFPA 1981 National Fire Protection Association standard specific to open-circuit SCBA for fire service use that contains additional requirements above the NIOSH certification.


NFPA 72 National Fire Alarm Code.


NFPA Standard 1931 The standard issued by the National Fire Protection Association that governs fire service ladder testing and certification.


9-1-1 Emergency telephone number that provides access to the public safety services in the community, region, and, ultimately, nation.


NOISH National Institute for Occupational Safety and Health, 42 CFR Part 84, sole responsibility for testing and certification of respiratory protection including fire service SCBA.


No-Knowledge Hardware Locking devices that require no key or special knowledge to operate.


Nozzle A tapered or constricted tube used to increase the speed or change the direction of water or other fluids.


Nozzle Flow The amount or volume of water that a nozzle will provide. Flow is measured in gallons per minute or liters per minute.


Nozzle Pressure The pressure required to effectively operate a nozzle. Pressure is measured in pounds per square inch or kilopascals.


Nozzle Reach The distance the water will travel after leaving the nozzle. Reach is a function of the pressure, which is converted to velocity or speed of the water leaving the nozzle.

Nozzle Reaction

Nozzle Reaction The force of nature that makes the nozzle move in the opposite direction of the water flow. The nozzle operator must counteract the thrust exerted by the nozzle to maintain control.


Occupancy Classifications The use for which a building or structure is designed.


Occupant Use Hose Hose that is used in standpipe systems for building occupants to fight incipient fires. It is usually 11/2-inch (38-mm) single-jacket hose similar to attack hose.


Occupational Safety and Health Administration (OSHA)The federal agency, under the Department of Labor, that is responsible for employee occupational safety.


Offensive Attack An aggressive attack on a situation where resources are adequate and capable of handling the situation.


One- or Two-Person Rope According to NFPA 1983, a one-person rope requires a minimum tensile strength of 4,500 pounds, and a two-person rope requires a minimum tensile strength of 9,000 pounds.

Open-Circuiit SCBA

Open-Circuit SCBA A type of SCBA unit in which the exhaled air is vented to the outside atmosphere.


Operational Period The time frames for operations at an incident. At large-scale or complex incidents these will usually be eight- to twelve-hour time frames.


Operations Level The next level of training above awareness that provides the foundation which allows for the responder to perform defensive activities at a chemical incident.


Ordinary Tank A horizontal or vertical tank that usually contains combustible or other less hazardous chemicals. Flammable materials and other hazardous chemicals may be stored in smaller quantities in these types of tanks.


Organic A substance derived from living organisms.


OSHA 29 CFR 1910.134 Standard establishing minimum medical, training, and equipment levels for respiratory protection programs.

Outside Stem and Yoke Valve (OS&Y)Outside Stem and Yoke Valve (OS&Y)

Outside Stem and Yoke Valve (OS&Y) Has a wheel on a stem housed in a yoke or housing. When the stem is exposed or outside, the valve is open. Also called an outside screw and yoke valve.


Overpacked A response action that involves the placing of a leaking drum (or container) into another drum. There are drums made specifically to be used as overpack drums in that they are oversized to handle a normal size drum.


Oxidizer A catalyst in the breakdown of molecules.


Oxygen Deficient Atmosphere An atmosphere with an oxygen content below 19.5 percent by volume.


Packaging The bandaging and preparing of a patient to be moved from the place of injury to a stretcher.

Panel Doors

Panel Doors Doors with a solid stile and rails with panels made of wood or glass or other materials.

Panic Hardware

Panic Hardware Hardware mounted on doors that enable them to be opened by pushing from the inside.


Paragraph q The paragraph within HAZWOPER that outlines the regulations that govern emergency response to chemical incidents.

Paramedic (EMT-P)

Paramedic (EMT-P) An individual trained and certified to provide advanced life support emergency medical care, including drug therapy.


Parapet The projection of a wall above the roofline of a building.

Partial-Thickness Burns

Partial-Thickness Burns Burns affecting the entire skin structure that lies over the top of the fatty tissues and muscles causing skin to turn red and blistering of the skin.


Passport A term given to a specific accountability system where crews are tracked using a card (passport) with all members listed. An accountability manager tracks the passports on an accountability board.


PDD 39 Presidential Decision Directive 39, which established the FBI as the lead agency in terrorism incidents responsible for crisis management. It also established FEMA as the lead for consequence management.


Permeation The movement of chemicals through chemical protective clothing on a molecular level; does not cause visual damage to the clothing.


Permissible Exposure Limit (PEL) An OSHA value that regulates the amount of a chemical that a person can be exposed to during an eight-hour day.

Personal Alert Safety System (PASS)

Personal Alert Safety System (PASS) A device that emits a loud alert or warning that the wearer is motionless.


Personal Size-Up A continuous mental evaluation of an individual’s immediate environment, facts, and probabilities.


Personnel Accountability Report (PAR) This is an organized roll call of all units assigned to an incident.

Photo-Ionization Detector (PID)

Photo-Ionization Detector (PID) An air monitoring devvice used by HAZMAT teams to determine the amount of toxic materials in the air.

Piercing Nozzles

Piercing Nozzles Originally designed to penetrate the skin of aircraft and now have been modified to pierce through building walls and floors.

Pike Pole

Pike Pole See Hook.


Pipe Chases A construction term used to describe voids designed to house building water supply and waste pipes. The term electrical chase is used for wiring.

Pitot GaugePitot Gauge

Pitot Gauge A device with an opening in its bladeshaped section that allows water to flow to a Bourdon gauge and registers the flowing discharge pressure of an orifice.


Pllan View A drawing or diagram of a building or area as seen from directly overhead. May include a site plan or a floor plan.


Platform Framing A style of wood frame construction in which each story is built on a platform, providing fire stopping at each level.


Polar Solvent A material that will mix with water, diluting itself.


Polar Solvent Type of Foam or Alcohol-Resistant Foam Foam that is compatible with alcohol and/or polar solvents by creating a polymeric barrier between the water in the foam and the polar solvent.


Polymeric Barrier A separation barrier made up of polymer or a chain of molecules linked in a series of long strands. This separates a polar solvent from an ATC foam blanket.


Polymerize A chain reaction in which the material quickly duplicates itself and, if contained, can be very explosive.


Portable Hydrant or Manifold Like a large water thief and may have one or more intakes and numerous outlets to allow multiple hoselines to be utilized with or without a pumper at the fire location.

Portable Water TanksPortable Water Tanks

Portable Water Tanks Collapsible or infaltable temporary tanks for the storage of water that is deumped from tankers or tenders. Usually carried by the tender to set up a dump site.


Positive Pressure A feature of SCBA providing a continuous supply of air, delivered by the regulator to the face piece, keeping toxic gases from entering. This pressure (11/2 to 2 psi, depending on the manufacturer) is slightly above atmospheric pressure.

Post Indicator Valve (PIV)Post Indicator Valve (PIV)

Post Indicator Valve (PIV) A control valve that is mounted on a post case with a small window, reading either “OPEN” or “SHUT.”


Post-Incident Thought Patterns A phenomenon that describes an individual’s inattentiveness following a significant incident. Post-incident thought patterns can lead to injuries or even death.

Preaction System

Preaction System Similar to the dry pipe and deluge systems. The system has closed piping and heads with air under no or little pressure, but the water does not flow until signaled open from a seperate fire detection system. The preaction valve then opens and allows water to flow through the system to the closed heads. When an individual head is heat activated, it opens and water attacks the fire. Usually used when water can cause a large dollar loss.


Prearrival Instructions Self-help instructions intended to enhance the overall safety of the citizen until first responders arrive on the scene.


Pre-Incident Management Advance planning of firefighting tactics and strategies or other emergency activities that can be anticipated to occur at a particular location. Often referred to as preplanning.


Pressure The force, or weight, of a substance, usually water, measured over an area.


Pressure-Regulating Device Designed to control the head pressure at the outlet of a standpipe system to prevent excessive nozzle pressures in hoselines.


Primary Hole Ventilation term used to describe the first holes to be cut in a roof. They must be located as close to directly over the fire as possible to prevent laterally drawing the fire across unburned areas.


Protein Foam Made from chemically broken down natural protein materials, such as animal blood, that have metallic salts added for foaming.

Prying Tools

Prying Tools The group of tools used to separate objects by means of a mechanical advantage.


Psychological Decon The process performed when persons who have been involved in a situation think they have been contaminated and want to be decontaminated. Responders who have identified that the persons have not been contaminated should still consider what can be done to make them feel better.

Pulling Tool

Pulling Tool The group of tools used to pull away materials.


Pulmonary Edema Fluid filling the lungs causing death by drowning.


Pump Operator A generic term to describe the person responsible for operating a fire apparatus pump. Other commonly used titles include motor pump operator, engineer, technician, chauffeur, and driver/operator.


Puncture An injury caused by an object that has stabbed the body.


Purlins A series of wood beams placed perpendicular to steel trusses to help support roof decking.


Pyrolysis Decomposition or transformation of a compound caused by heat.


Quint A combination fire service apparatus with components of both engine company and a truck


Rabbeted A door stop that is cut (rabbeted) into the door frame. On metal door frames the stop is an integral part of the frame.

Radial Pulse

Radial Pulse The pulse located in either wrist.


Radiological Dispersion Device (RDD) An explosive device that spreads radioactive material throughout an area.


Rafter A wood joist that is attached to a ridge board to help form a peak.


Rapid Intervention Crew (RIC) See Rapid Intervention Team.

Rapid Intervention Team

Rapid Intervention Team A company designated to search for and rescue trapped or lost firefighters. Depending on location, may also be called a FAST.


Rate of Spread A ground cover fire’s forward movement or spread speed. Usually expressed in chains or acres per hour.


RECEO Acronym coined by Lloyd Layman standing for Rescue, Exposures, Confinement, Extinguishment, and Overhaul.


Recommended Exposure Limit (REL) An exposure value established by NIOSH for a ten-hour day, forty-hour workweek. Similar to the PEL and TLV.


Reducers Used to connect a larger hose to a smaller one.


Reel Coil Memory that wire develops from having been placed on a wooden spool as it is being manufactured.


Regulations Developed and issued by a governmental agency and have the weight of law.


Rehab A shortened word meaning rehabilitation. Rehab typically consists of rest, medical evaluation, hydration, and nourishment.


Relief Valve A device designed to vent pressure in a tank, so that the tank itself does not rupture due to an increase in pressure. In most cases these devices are spring loaded so that when the pressure decreases the valve shuts, keeping the chemical inside the tank.


Remote Shutoffs Valves that can be used to shut off the flow of a chemical. The term remote is used to denote valves that are located away from the spill.


Reportable Quantity (RQ) Both the EPA and DOT use the term. It is a quantity of chemicals that may require some type of action, such as reporting an inventory or reporting an accident involving a certain amount of the chemical.


Rescue Those actions that firefighters perform at emergency scenes to remove victims from imminent danger or to extricate them if they are already entrapped.

Rescue Company

Rescue Company The unit designation of a group of firefighters assigned to perform specialized rescue work and/or tactics and functions such as forcible entry, search and rescue, ventilation, and so on.

Rescue Specialist

Rescue Specialist A firefighter with specialized training and experience in areas such as high angle rope rescue, confined space, trench, or structural collapse rescue.


Residential Sprinkler System Smaller and more affordable version of a wet or dry pipe sprinkler system designed to control the level of fire involvement such that residents can escape.


Residual Pressure The pressure in a system after water has begun flowing.


Respiratory Protection Programs Management programs designed to ensure employee respiratory protection as required by OSHA 29 CFR 1910.134 and NFPA 1500.


Respiratory System The system of the human body that exchanges oxygen and waste gases to and from the circulatory system.

Retard Chamber

Retard Chamber Acts to prevent false alarms from a sudden pressure surge in the water supply by collecting a small volume of water before allowing a continued flow to the alarm device. The water from a surge is drained from a small hole in the bottom of the collection chamber.


Retention The digging of a hole in which to collect a spill. Can be used to contain a running spill or collect a spill from the water.


Ricin A biological toxin that can be used by a terrorist or other person attempting to kill or injure someone. It is the easiest terrorist agent to produce and one of the most common.


Ridge The land running between mountain peaks or along a wide peak. A high area separating two drainages running parallel with them.


Ringdown Circuits Telephone connection between two points. Going “off-hook” on one end of the circuit causes the telephone on the other end of the circuit to “ring” without having to dial a number.


Risk The chance of injury, damage, or loss; hazard.


Risk-Based Response An approach to responding to a chemical incident by categorizing a chemical into a fire, corrosive, or toxic risk. Use of a risk-based approach can assist the responder in making tactical, evacuation, and PPE decisions.


Risk/Benefit An evaluation of the potential benefit that a task will accomplish in relationship to the hazards that will be faced while completing the task.


Risk Management The process of minimizing the chance, degree, or probability of damage, loss, or injury.


River BottomTopographic feature where water runs from higher elevations to lower. Can be dry or wet depending on season or recent rains.


Rollover A phenomenon where the burning of superheated gases from fire extends into the top areas of the compartment in the upper thermal layers.

Rope Hose Tool

Rope Hose Tool About 6 feet (2 m) of 1/2-inch (13-mm) rope spliced into a loop with a large metal hook at one end and a 2-inch (50-mm) ring at the other. Used to tie in hose and ladders, carry hose, and perform many other tasks requiring a short piece of rope.

Round Turn Formed by continuing the loop on around until the sections of the standing part on either side of the round turn are parallel to one another.

Run Card System

Run Card System System of cards or other form of documentation that provides specific information on what apparatus and personnel respond to specific areas of a jurisdiction.

Running End

Running End End of the rope that is not rigged or tied off.


Saddle A pass between two peaks that has a lower elevation than the peaks. Wind will pass through this area faster than over the peaks, so fire is drawn into this feature.

Safety Containers

Safety Containers A storage can that eliminates vapor release by using a self-closing lid. Also contains a flame arrestor in the dispenser opening.


Sea Containers Shipping boxes that were designed to be stacked on a ship, then placed onto a truck or railcar.


Search and Rescue Attempts by fire and emergency service personnel to coordinate and implement a search for a missing person and then effect a rescue.

Secondary Containment

Secondary Containment Any approved method that will prevent the runoff of spilled hazardous materials and confine it to the storage area.


Secondary Hole A ventilation hole that is opened only after the primary holes have been opened. It complements the primary holes.


Sectional View A vertical view of a structure as if it were cut in two pieces. Each piece is a cross section of the structure showing roof, wall, horizontal floor construction, and the location of stairs, balconies, and mezzanines.


Sector An area established and identified for a specific reason, typically because a hazard exists within the sector. The sectors are usually referred to as hot, warm, and cold sectors and provide an indication of the expected hazard in each sector. Sometimes referred to as a zone.


Self-Accelerating Decomposition Temperature (SADT) Temperature at which a material will ignite itself without an ignition source present. Can be compared to ignition temperature.

Self-Contained Breathing Apparatus (SCBA)

Self-Contained Breathing Apparatus (SCBA) A type of respiratory protection in which a self-contained air supply and related equipment are worn or attached to the user. Fire service SCBA is required to be of the positive pressure type.


Sensitizer A chemical that after repeated exposures may cause an allergic-type effect on some people.


Setting The finishing step, making sure that the knot is snug in all directions of pull.

Severance The cutting off of components (i.e., brake pedal, steering wheel) in a vehicle.


Shear A force that tends to tear a material by causing its molecules to slide past each other.


Sheetrock A trademark and another name for plasterboard.


Shelter in Place A form of isolation that provides a level of protection while leaving people in place, usually in their homes. People are usually sheltered in place when they may be placed in further danger by an evacuation.


Shock A serious condition caused by a problem or failure of the circulatory system that results in a decrease of oxygen and vital nutrients to the body’s tissues. Also known as hypoperfusion.


Shock Load A load or impact being transferred to a rope suddenly and all at one time.


Shoring The use of timbers to support and/or strengthen weakened structural members (roofs, floors, walls, etc.) in order to avoid a secondary collapse during the rescue operation.


Short-Term Exposure Limit (STEL) A fifteen minute exposure to a chemical followed by a onehour break between exposures. Only allowed four times a day.


Shoulder Load Hose load designed to be carried on the shoulders of firefighters.

Shuttle Operation

Shuttle Operation The cycle in which mobile water supply apparatus is dumped, moves to a fill site for refilling, and is returned to the dump site.


Siamese A device that connects two or more hoselines into one line with either a clapper valve or gate valve to prevent loss of water if only one line is connected.


Sick Building A term that is associated with indoor air quality. A building that has an air quality problem is referred to as a sick building. In a sick building, occupants become ill as a result of chemicals in and around the building.


Sick Building Chemical When a building is referred to as a sick building, certain chemicals exist within that cause health problems for the occupants. These chemicals are referred to as sick building chemicals.


Simple Beam A beam supported at the two points near its end.


Slab DoorSee Flush or Slab Doors.


Slot Loads Narrow section of a hose bed where hose is flat loaded in the slot.


Small Lines or Small-Diameter Hose Hose less than 21/2 inches (63 mm) in diameter.

Soft Suction Hose

Soft Suction Hose Large-diameter woven hose used to connect a pumper to a hydrant. Also known as a soft sleeve.


Solid A state of matter that describes materials that may exist in chunks, blocks, chips, crystals, powders, dusts, and other types. Ice is an example.

Solid Stream Nozzles

Solid Stream Nozzles Type of nozzle that delivers an unbroken or solid stream of water to the fire. Also called solid tip, straight bore, or smooth bore.

Solid-Core Door

Solid-Core Door Doors made of solid material such as wood or having a core of solid material between face panels.


Solubility A liquid’s ability to mix with another liquid.


Spalling Deterioration of concrete by the loss of surface material due to the expansion of moisture when exposed to heat.


Span of Control The ability of one individual to supervise a number of other people or units. The normal range is three to seven units or individuals, with the ideal being five.

Spanner Wrenches

Spanner Wrenches Used to tighten or loosen couplings. They may also be useful as a pry bar, door chock, gas valve control, and so on.

Speaking Trumpet

Speaking Trumpet Trumpet used by a foreman or crew boss to shout orders above the noise of firefighting activities.


Special Egress Control Device Door hardware that will release and unlock the door a maximum of fifteen seconds after it has been activated by pushing on the bar.


Specialist Level A level of training that provides for a specific type of training, such as railcar specialist; someone who has a higher level of training than a technician.


Specific Gravity Weight of a liquid in relation to water. Water is rated 1.


Specification (Spec) Plates All trucks and tanks have a specification plate that outlines the type of tank, capacity, construction, and testing information.

Spinal Immobilization

Spinal Immobilization The process of protecting patients against further injury by securing them to a backboard or other rigid device designed to minimize movement.


Sprain Injury to the ligaments that hold the body’s joints together and allow them to move.


Sprinkler System Designed to automatically distribute water through sprinklers placed at set intervals on a system of piping, usually in the ceiling area, to extinguish or control the spread of fires.


StagingPart of the operations section where apparatus and personnel assigned to the incident are available for deployment within three minutes.


Stairwell An enclosed stairway attached to the side of a high-rise building or in the center core of same.


Standard of Care A legal term that means for every emergency medical incident, an emergency responder should treat the patient in the same manner as another emergency responder with the same training.

Standing Operating Procedure (SOP)

Standing Operating Procedure (SOP) Specific information and instruction on how a task or assignment is to be accomplished.


Standard Transportation Commodity Code (STCC)A number assigned to chemicals that travel by rail.


Standards Usually developed by consensus groups establishing a recommended practice or standard to follow.

Standing Part

Standing Part The part of a rope that is not used to tie off.

Standpipe SystemsStandpipe systems

Standpipe Systems Piping systems that allow for the manual application of water in large buildings.


State Emergency Response Committee (SERC) A group that ensures that the state has adequate training and resources to respond to a chemical incident.

States of Matter

States of Matter Describes in what form matter exists, such as solids, liquids, or gases.


Static A rope having very little (less than 2 percent) elongation at normal safe working loads.


Static Pressure The pressure in the system with no hydrants or water flowing.


Staypoles The stabilizer poles attached to the sides of Bangor ladders that are used to assist in the raising of this type of ladder. Once raised, they are not used to support the extended ladder.


Steepness of Slope The degree of incline or vertical rise to a given piece of land.

Storz CouplingsStorz Couplings

Storz Couplings The most popular of the nonthreaded hose couplings.


Straight Stream A nozzle pattern that creates a hollow stream, similar in shape to the solid stream pattern, but the straight stream pattern must pass around the baffle of the nozzle. Newer fog nozzle designs, especially the automatic nozzles, only have this hollow effect from the tip on and, hence, create a solid stream with good reach and penetration abilities, some better than solid stream nozzles.


Strainers Placed over the end of a suction hose to prevent debris from being sucked into the pump. Some strainers have a float attached to keep them at or near the water’s surface. A different style of strainer or screen is located on each intake of a pump.


Strategic Goals The overall plan developed and used to control an incident.


Stream Shape The arrangement or configuration of the water or other agent droplets as they leave the nozzle.


Stream Straighter A metal tube, commonly with metal vanes inside it, between a master stream appliance and its solid nozzle tip. The purpose is to reduce any turbulence in the stream, allowing it to flow straighter.


Strike Plate The metal piece attached to a door jamb into which the lock bolt slides. Also called a strike or striker.

Striking Tools

Striking Tools The group of tools designed to deliver impact forces to break locks or drive another tool.


Sublimation The ability of a solid to go to the gas phase without being liquid.

Superficial Burns

Superficial Burns Burns affecting the outermost layer of skin, which typically cause redness of the skin, swelling, and pain.


Superfund Amendments and Reauthorization Act (SARA) A law that regulates a number of environmental issues, but is primarily for chemical inventory reporting by industry to the local community.

Supplied Air Respirator (SAR)

Supplied Air Respirator (SAR) A type of SCBA in which the self-contained air supply is remote from the user, and the air is supplied by means of air hoses.


Supply Hose or Large-Diameter Hose (LDH) Larger hose [31/2 inches (90 mm) or bigger] used to move water from the water source to attack units. Common sizes are 4 and 5 inches (100 to 125 mm).


Surface-to-Mass Ratio Exposed exterior surface area of a material divided by its weight.


Suspension System The springs, shock absorbers, tires, and so on, of a vehicle.


Tactics The specific operations performed to satisfy the strategic goals for an incident.


Tactilely Using the sense of touch to feel for any differences or abnormality.

Tag/Guide Lines

Tag/Guide Lines Tag lines are ropes held and controlled by firefighters on the ground or lower elevations in order to keep items being hoisted from banging against or getting caught on the structure as they are being hoisted.


Tanker The term given to aircraft capable of carrying and dropping water or fire retardant. Some departments still use the term to describe land-based water apparatus.


Target Hazard An occupancy that has been determined to have a greater than average life hazard or complexity of firefighting operations. Such occupancies receive a high priority in the pre-incident management process and often a higher level of first-alarm response assignment.


TDD Device that allows citizens to communicate with the telecommunicator through the use of a keyboard over telephone circuits instead of voice communications.


Teamwork A number of persons working together in an effort to reach a common goal.


Technician Level A high level of training that allows specific offensive activities to take place, to stop or handle a chemical incident.


Telecommunicator Individual whose primary responsibility is to receive emergency requests from citizens, evaluate the need for a response, and ultimately sound the alarm that sends first responders to the scene of an emergency.


Tempered Glass Plate glass that has been heat treated to increase its strength.


Tender The abbreviated term for water tender. A water tender is defined as a land-based mobile water supply apparatus. Some departments still use the term tender to describe a hose-carrying support apparatus.


Tensile Strength Breaking strength of a rope when a load is applied along the direction of the length, generally measured in pounds per square inch.


Tension A force that pulls materials apart.


Terra Cotta Tiles composed of clay and sand that are kiln fired. May be structural or decorative.


Terrorism Acts of violence that are arbitrarily committed against lives or property and intended to create fear and anxiety.


Tether Line A rope that is held by a team on shore during a water rescue to be used to haul the rescuer and victim back to shore.

Thermal Burns

Thermal Burns Burns caused by heat or hot objects.


Thermal Layering The stratification of gases produced by fire into layers based on their temperature.


Thermal Level A layer of air that is of the same approximate temperature.

Thermal Plume

Thermal Plume A column of heat rising from a heat source. A fully formed plume will resemble a mushroom as the upper level of the heat plume cools, stratifies, and begins to drop outside the rising column.


Thermal Protective Performance (TPP) A rating level, expressed in seconds, used to characterize the protective qualities of a PPE component before serious injury is experienced by the wearer.


Threshold Limit Value (TLV) An exposure value that is similar to the PEL, but is issued by the ACGIH. It is based on an eight-hour day.

Through-the-Lock Method

Through-the-Lock Method A method of forcible entry in which the lock cylinder is removed by unscrewing or pulling and the internal lock mechanism is operated to open a door. Also, the family of tools used to perform this operation.


Tidal Changes The rising and falling of the surface water levels due to the gravitational effects between the Earth and the moon. In some areas, these changes are insignificant but in others there is more than 40 feet of difference between high and low tide.


Tip Arc The path that a ladder’s tip will take while being raised.

Torsion Load

Torsion Load A load parallel to the cross section of the supporting member that does not pass through the long axis. A torsion load tries to “twist” a structural element.


Total Flooding System Used to protect an entire area, room, or building by discharging an extinguishing agent that completely fills or floods the area with the extinguishing agent to smother or cool the fire or break the chain reaction.


Tote A large tank usually 250 to 500 gallons, constructed to be transported to a facility and dropped for use.

Tower Ladder

Tower Ladder An apparatus with a telescopic boom that has a platform on the end of the boom or ladder. It can be extended or retracted and rotated like an aerial ladder.


Toxicity Poisonous level of a substance.


Toxins Disease-causing materials that are extremely toxic and in some cases more toxic than other warfare agents such as nerve agents.


TRACEM An acronym for the types of hazards that exist at a chemical incident: thermal, radiation, asphyxiation, chemical, etiological, and mechanical.


Triage A quick and systematic method of identifying which patients are in serious condition and which patients are not, so that the more seriously injured patients can be treated first.

Triple Combination Engine Company

Triple Combination Engine Company Fire apparatus that can carry water, pump water, and carry hose and equipment.

Truck Company

Truck Company The unit designation of a group of firefighters assigned to perform tactics and functions such as forcible entry, search and rescue, ventilation, and so on.


Truss A rigid framework using the triangle as its basic shape.


Tunnel Vision The focus of attention on a particular problem without proper regard for possible consequences or alternative approaches.


Tunneling The digging and debris removal accompanied by appropriate shoring to safely move through or under a pile of debris at a structural collapse incident.


Turntable The rotating platform of a ladder that affords an elevating ladder device the ability to turn to any target from a fixed position.


Two In/ Two Out The procedure of having a crew standing by completely prepared to immediately enter a structure to rescue the interior crew should a problem develop.

Type A Reporting System

Type A Reporting System System in which an alarm from a fire alarm box is received and retransmitted to fire stations either manually or automatically.

Type B Reporting System

Type B Reporting System System in which an alarm from a fire alarm box is automatically transmitted to fire stations and, if used, to outside alerting devices.

Type I Fire Resistive Construction

Type I Fire Resistive Construction Type in which the structural members, including walls, columns, beams, girders, trusses, arches, floors, and roofs, are of approved noncombustible or limited combustible materials with sufficient fire-resistive rating to withstand the effects of fire and prevent its spread from story to story.

Type II Nonconbustible Construction

Type II Noncombustible Construction Type not qualifying as Type I construction, in which the structural members, including walls, columns, beams, girders, trusses, arches, floors, and roofs, are of approved noncombustible or limited combustible materials with sufficient fire-resistive rating to withstand the effects of fire and prevent its spread from story to story.

Type III Ordinary ConstructionType III Ordinary Construction

Type III Ordinary Construction Type in which the exterior walls and structural members that are portions of exterior walls are of approved noncombustible or limited combustible materials, and interior structural members, including walls, columns, beams, girders, trusses, arches, floors, and roofs, are entirely or partially of wood of smaller dimension than required for Type IV construction or of approved noncombustible or limited combustible materials.

Type IV Heavy Timber Construction

Type IV Heavy Timber Construction Type in which exterior and interior walls and structural members that are portions of such walls are of approved noncombustible or limited combustible materials. Other interior structural members, including columns, beams, girders, trusses, arches, floors, and roofs, shall be of solid or laminated wood without concealed spaces.

Type V Wood Frame Construction

Type V Wood Frame Construction Type in which the exterior walls, bearing walls, columns, beams, girders, trusses, arches, floors, and roofs are entirely or partially of wood or other approved combustible material smaller than the material required for Type IV construction.

Underground Storage Tanks (UST)

Underground Storage Tanks (UST) Tank that is buried under the ground. The most common are gasoline and other fuel tanks.


Undesigned Load A load not planned for or anticipated.


Unified Command The structure used to manage an incident involving multiple response agencies or when multiple jurisdictions have responsibility for control of an incident.


Unity of Command One designated leader or officer to command an incident.


Upper Explosive Limit (UEL) The upper part of the flammable range. Above the UEL, fire or an explosion cannot occur because there is too much fuel and not enough oxygen.


Utility Rope Rope used for utility purposes only. Some of the tasks utility ropes are used for in most every fire department are hoisting tools and equipment, cordoning off areas, and stabilizing objects. Also used as ladder halyards.


Vacuum (Negative) Pressure The measurement of the pressure less than atmospheric pressure, which is usually read in inches of mercury (in. Hg or mm Hg) on a compound gauge.


Vapor Density Weight of a gas in relation to air. Air is rated 1.


Vapor Dispersion The intentional movement of vapors to another area, usually by the use of master streams or hoselines.

Vapor Pressure

Vapor Pressure The amount of force that is pushing vapors from a liquid. The higher the force the more vapors (gas) being put into the air.


Vapor Suppression Ability to contain or control the production of fuel vapors.


Vaporization The process in which liquids are converted to a gas or vapor.


Variable, Adjustable, or Selectable Gallonage Nozzle Nozzle that allows the nozzleperson to select the flow, with usually two or three choices, and the pattern.


Veins The blood vessels, or tubes, within the body that carry blood lacking oxygen and nutrients back to the heart.


Velocity Pressure The forward pressure of water as it leaves an opening.


Veneer A covering or facing, not a load-bearing wall, usually with brick or stone.


Venous Bleeding Bleeding from a vein.

Venturi Principle

Venturi Principle A process that creates a low-pressure area in the induction chamber of the eductor and allows the foam concentrate to be drawn into and mix with the water stream.


Vertical Ventilation Channeled pathway for fire ventilation via vertical openings.


Vesicants A group of chemical agents that cause blistering and irritation of the skin. Commonly referred to as blister agents.


Vicarious Experience A shared experience by imagined participation in another’s experience.


Visqueen A trade name for black plastic. It can be used very effectively in salvage and overhaul operations.


Voice Inflection Change of tone or pitch of voice.


Voids Spaces within a collapsed area that are open and may be an area where someone could survive a building collapse.

Wall Indicator Valve (WIV)

Wall Indicator Valve (WIV) A control valve that is mounted on a wall in a metal case with a small window, reading either “OPEN” or “SHUT.”


Watch Dogs Trained dogs that will bark and create a commotion, but will not attack.


Water Columning A condition in a dry pipe sprinkler system in which the weight of the water column in the riser prevents the operation of the dry pipe valve.


Water Curtain Nozzle Designed to spray water to protect exposures against heat by wetting the exposure’s surface.


Water Hammer A sudden surge of pressure created by the quick opening or closing of valves in a water system. The surge is capable of damaging piping and valves.


Water Table The level of groundwater under the surface.


Water Tender The term given to land-based water supply apparatus.


Water Thief A variation of the wye that has one inlet and one outlet of the same size plus two smaller outlets with all of the outlets being gated. The standard water thief usually has a 21/2-inch (65-mm) inlet with one 21/2-inch (65-mm) and two 11/2-inch (38-mm) outlets.


Waybill A term that may be used in conjunction with consist, but is a description of what is on a specific railcar.


Weapon of Mass Destruction (WMD) A term that is used to describe explosive, chemical, biological, and radiological weapons used for terrorism and mass destruction.


Web The vertical portion of a truss or I beam that connects the top chord with the bottom chord.

Web Gear

Web Gear The term given to a whole host of personal items carried on a belt / harness arrangement worn by wildland firefighters. Items include water bottles, a fire shelter, radio, and day sack.


Webbing Nylon strapping, available in tubular and flat construction methods.

Webbing Sling

Webbing Sling Approximately 12 to 15 feet of rescue webbing tied end to end, forming a continuous loop.


Western or Platform Framing A style of wood frame construction in which each story is built on a platform, providing fire stopping at each level.


Wet Chemicals Extinguishing agents that are waterbased solutions of potassium carbonate–based chemicals, potassium acetate–based chemicals, or potassium citrate–based chemicals, or a combination.

Wet Pipe Sprinkler System

Wet Pipe Sprinkler Systema Has automatic sprinklers attached to pipes with water under pressure all the time.


Wheatstone Bridge Sensor A type of combustible gas sensor that uses a heated coil of wire to determine the presence of flammable gases.

Wire Glass

Wire Glass Glass with a wire mesh embedded between two or more layers to give increased fire resistance.


Work Hardening A phrase given to the effort and physical training designed to prepare an individual to better perform the physical tasks that are expected of the individual. Work hardening is key in preventing injuries resulting from typical firefighting tasks.

Working End

Working End The end of the rope that is utilized to secure/tie off the rope.

Working Length

Working Length The length of the ladder that spans the distance from the ground to the point of contact with the structure. This does not include any distance the ladder might go beyond the point of contact as would be the case when the tip extends beyond the roof.


Wye A device that divides one hoseline into two or more. The wye lines may be the same size or smaller size and the wye may or may not have gate control valves to control the water flow.



Zones An area established and identified for a specific reason, typically because a hazard exists within the zone. The zones are usually referred to as hot, warm, and cold zones and provide an indication of the expected hazard in each zone. Sometimes referred to as a sector.


Zoning A term given to the establishment of specific hazard zones; that is, hot zone, warm zone, cold zone. Also collapse zones.