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Absorption Passage of materials (such as toxins) through some body surface into body fluids and tissue.
Acceptance Testing (Proof Test) Preservice tests on fire apparatus or equipment performed at the factory or after delivery to assure the purchaser that the apparatus or equipment meets bid specifications.
Accordion Load Arrangement of fire hose in a hose bed or compartment in which the hose lies on edge with the folds adjacent to each other.
Acute Single exposure (dose) or several repeated exposures to a substance within a short time period.
Adapter Fitting for connecting hose couplings with dissimilar threads but with the same inside diameter.
Administration The government agency having authority over port operations.
Aerate Act of mixing with air.
Aeration Introduction of air into a foam solution to create bubbles that result in finished foam.
Aerial Device General term used to describe the hydraulic aerial ladder, elevating platform, or telescoping or articulating booms attached to an automotive fire apparatus that have the means to reach at least 65 feet (20 m) above grade, with many being capable of reaching more than 100 feet (30 m).
Aerial Fuels Standing and supported live and dead combustibles not in direct contact with the ground and consisting mainly of foliage, twigs, branches, stems, cones, bark, and vines.
Aerial Ladder A rotating, power-operated (usually hydraulically) ladder, mounted on a self-propelled automotive fire apparatus.
Aerial Ladder Platform A power-operated (usually hydraulically) aerial device which combines an aerial ladder with a personnel carrying platform supported at the end of the ladder.
A-frame collapse This pattern of collapse occurs when the floor and/or roof assemblies on both sides of a center wall collapse into what might be seen as opposing lean-to collapses. This pattern offers a good chance of habitable void spaces on both sides of the center wall.
Agency for Toxic Substances and Disease Registry (ATSDR) Lead U.S. public health agency responsible for implementing the health-related provisions of the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA), and charged with assessing health hazards at specific hazardous waste sites, helping to prevent or reduce exposure and the illnesses that result, and increasing knowledge and understanding of the health effects that may result from exposure to hazardous substances.
Air Bag Inflatable bag designed into the steering wheel, dashboard, or doors of an automobile that inflates immediately when the vehicle is impacted.
Air Chisel Pneumatic chisel is useful for extrication work; designed to operate at air pressures between 100 and 150 psi (700 kPa and 1 050 kPa).
Air Knife Hand-held tools can blast away surface dirt with great efficiency.
Air Vacuum Closely related to the air knife, air vacuums are hand-held tools that can use the same air compressor as the air knife, but they operate on slightly less pressure.
Air-Aspirating Foam Nozzle Foam nozzle especially designed to provide the aeration required to make the highest quality foam possible; most effective appliance for the generation of low-expansion foam.
Air-Purifying Respirator (APR) Respirator with an air-purifying filter, cartridge, or canister that removes specific air contaminates by passing ambient air through the air-purifying element; may have a full or partial facepiece.
All Clear Signal given to the incident commander that a specific area has been checked for victims and none have been found or all found victims have been extricated from an entrapment.
Allergen Material that can cause an allergic reaction of the skin or respiratory system. Also called sensitizer.
Alpha Radiation Consists of particles having a large mass and positive electrical charge; least penetrating of the three common forms of radiation. It is normally not considered dangerous to plants, animals, or people unless it gets into the body.
Americans with Disabilities Act (ADA) of 1990 - Public Law 101-336 A federal statute intended to remove barriers — physical and otherwise — that limit access by individuals with disabilities.
Aqueous Film Forming Foam (AFFF) Synthetic foam concentrate that, when combined with water, can form a complete vapor barrier over fuel spills and fires and is a highly effective extinguishing and blanketing agent on hydrocarbon fuels. Also called light water.
Arc A luminous discharge of electricity across a gap. Arcs produce very high temperature.
Arched Roof Any of several different types of roofs of which all are curved or arch shaped, resembling the top half of a horizontal cylinder. Typical applications are on supermarkets, auditoriums, bowling centers, sports arenas, and aircraft hangars.
Around-the-Pump Proportioner Apparatus-mounted foam proportioner. A small quantity of water is diverted from the apparatus pump through an inline proportioner where it picks up the foam concentrate and carries it to the intake side of the pump; most common apparatus-mounted foam proportioner in service. Also see Foam Proportioner and Proportioning.
Arson Crime of willfully, maliciously, and intentionally starting a fire (firesetting) or causing an explosion to destroy one’s property or the property of another. Precise legal definitions vary among jurisdictions, wherein it is defined by statutes and judicial decisions.
Ascender Mechanical contrivance, used when climbing rope, that allows upward movement but not downward movement.
Aspect (1) Position facing a particular direction; exposure. (2) Compass direction toward which a slope faces.
Asphyxiant Any substance that prevents oxygen from combining in sufficient quantities with the blood or from being used by body tissues.
Assembly Two or more interconnected structural components combined to meet a specific function or design requirement. Typical assemblies are roof trusses, wall frames, and doors including their frames.
Assigned Resources Resources checked in and assigned an objective on an incident.
A-Tool A prying tool with a sharp notch with cutting edges machined into it. The notch resembles the letter A. This tool is designed to cut behind the protective collar of a lock cylinder and maintain a hold so that the lock cylinder can be pried out.
ATSDR Abbreviation for Agency for Toxic Substances and Disease Registry.
Attic An open space between the roof and ceiling of a building; most commonly found in single- and multi-family residential occupancies. Attics provide open spaces in which fires can burn undetected or spread throughout a structure.
Autoignition Ignition that occurs when a substance in air, whether solid, liquid, or gaseous, is heated sufficiently to initiate or cause self-sustained combustion without an external ignition source.
Autoignition Temperature Same as ignition temperature except that no external ignition source is required for ignition because the material itself has been heated to ignition temperature. The temperature at which autoignition occurs through the spontaneous ignition of the gases or vapor given off by a heated material.
Automatic (constant pressure) nozzles Fog stream nozzle that automatically corrects itself to provide a good stream at the proper nozzle pressure.
Automatic Location Identification (ALI) Enhanced 9-1-1 feature that displays the address of the party calling 9-1-1 on a screen for use by the public safety telecommunicator. Usually used in tandem with automatic number identification (ANI) services.
Automatic Number Identification (ANI) Enhanced 9-1-1 feature that displays the phone number of the party calling 9-1-1 on a screen for use by the public safety telecommunicator.
Automatic Sprinkler System System of water pipes, discharge nozzles, and control valves designed to activate during fires by automatically discharging enough water to control or extinguish a fire. Also called sprinkler system.
Automatic Vehicle Locator (AVL) System that uses global positioning satellites to determine the exact location of units in the field. This information is relayed to public safety communications centers to help determine the closest unit to send during an emergency.
Automatic-Closing Door Self-closing door normally held in the open position by an automatic releasing device such as a magnetic hold-open device. When the door is released by the hold-open device, it closes.
Available Resources Resources not assigned to an incident and available for an assignment.
Awning Window Window consisting of large sections of glass, usually double-strength, set in a metal or wood frame and are hinged along the top rail while the bottom rail swings out.
Axe Forcible entry tool that has a pick or flat head and a blade attached to a wood or fiberglass handle. Also called firefighter’s axe.Back to top
Backdraft Instantaneous explosion or rapid burning of superheated gases that occurs when oxygen is introduced into an oxygen-depleted confined space. The stalled combustion resumes with explosive force.
Balanced Pressure Proportioner A foam concentrate proportioner that operates in tandem with a fire water pump to ensure a proper foam concentrate-to-water mixture.
Bale Hook/Baling Hook Tool used for moving bales or boxed goods and for moving and overhauling stuffed furniture or mattresses. Also called Hay Hook.
Ball Valve Valve having a ball-shaped internal component with a hole through its center that permits water to flow through when aligned with the waterway.
Balloon Frame A type of wood-frame construction in which the studs in exterior walls extend from the basement or foundation to the roof. This type of construction allows fires to spread – often undetected – from the basement to the attic through the hollow walls.
Bam-Bam Tool A tool used to disassemble padlocks and trip its lock mechanism.
Bangor Ladder Large extension ladder that requires tormentor poles to steady the ladder as it is raised and lowered. Also called Bangor Ladder.
Bank-Down Application Method (Deflect) Method of foam application that may be employed on an un-ignited or ignited Class B fuel spill. The foam stream is directed at a vertical surface or object that is next to or within the spill area. The foam deflects off the surface or object and flows down onto the surface of the spill to form a foam blanket.
Bar Joist A joist constructed of steel with bars in the vertical web space. A common structural component in office buildings and other commercial structures. Very high strength to weight ratio except when exposed to the heat of a fire – then early failure is likely.
Bar-Screw Jack Jack used to hold loads under compression. It is commonly used in shoring work or other similar evolutions.
Batch-Mixing Production of foam solution by adding an appropriate amount of foam concentrate to a water tank before application. The resulting solution must be used or discarded following the incident.
Beam (1) Structural member subjected to loads, usually vertical, perpendicular to its length. (2) Main structural member of a ladder supporting the rungs or rung blocks. Also called Side Rail or Rail.
Becket Bend Knot used for joining two ropes. It is particularly well suited for joining ropes of unequal diameters or joining a rope and a chain. Also called Sheet Bend.
Bed Section Bottom section of an extension ladder. Also called Base Section.
Beta Radiation Type of radiation that can cause skin burns.
Bight Element of a knot formed by simply bending the rope back on itself (creating a loop) while keeping the sides parallel.
Biological Toxin Poison produced by living organisms.
Black Area already burned by a wildland fire.
Blast Pressure Wave Shock wave created by rapidly expanding gases in an explosion.
BLEVE Acronym for Boiling Liquid Expanding Vapor Explosion.
Blitz Attack To aggressively attack a fire from the exterior with a large diameter (2½-inch [65 mm] or larger) fire stream.
Block and Tackle Series of pulleys (sheaves) contained within a wood or metal frame. They are used with rope to provide a mechanical advantage for pulling operations.
Block A wooden or metal frame containing one or more pulleys called sheaves.
Boiling Liquid Expanding Vapor Explosion (BLEVE) Rapid vaporization of a liquid stored under pressure upon release to the atmosphere following major failure of its containing vessel. The failure of the containing vessel is the result of over-pressurization caused by an external heat source causing the vessel to explode into two or more pieces when the temperature of the liquid is well above its boiling point at normal atmospheric pressure.
Bolt Cutters Cutting tool designed to make a precise, controlled cut; used for cutting wire, fencing, bolts, and small steel bars.
Booster Reel Mounted reel on which booster hose is carried.
Bored Lock Lock installed within right angle holes bored in a door. Also called cylindrical lock.
Bowline Knot Knot used to form a loop in natural fiber rope.
Bowstring Truss A roof assembly with a curved (arched) top chord and a horizontal bottom chord. These assemblies are very strong except when exposed to direct flame contact when catastrophic failure without warning may occur.
Braided Rope Rope constructed by uniformly intertwining strands of rope together (similar to braiding a person’s hair).
Braid-on-Braid Rope Rope constructed with both a braided core and a braided sheath. The appearance of the sheath is that of a herringbone pattern.
Branch Organizational level of an incident management system having functional/geographic responsibility for major segments of incident operations. The branch level is organizationally between section and division/sector/group.
British Thermal Unit (Btu) Amount of heat energy required to raise the temperature of one pound of water one degree Fahrenheit. One Btu = 1.055 kilo joules (kJ).
Broken Stream Stream of water that has been broken into coarsely divided drops.
Brush Company Extinguishes wildland fires and protects structures in the wildland/urban interface.
Bunker Clothes General term for the equipment worn by firefighters and rescuers; includes helmets, coats, pants, boots, eye protection, gloves, protective hoods, self-contained breathing apparatus, and personal alert safety systems (PASS devices). Also called Bunker Clothes, Protective Clothing, Turnout Clothing, or Turnout Gear.
Burglar Block A metal rod or similar device that sometimes is barring or blocking patio sliding doors. This feature can easily be seen from the outside, and it virtually eliminates any possibility of forcing the door without breaking the glass.
Burning Bars Ultra-high temperature cutting devices capable of cutting through virtually any metallic, nonmetallic, or composite material. Also called exothermic cutting rods.
Butt (1) One coupling of a fire hose. (2) Hydrant outlet. (3) Heel (lower end) of a ladder. (4) Act of steadying a ladder that is being climbed.
Butt Spurs Metal safety plates or spikes attached to the butt end of ground ladder beams.
Butterfly Roof A V-shaped roof in which the two sides slope toward a valley in the middle. An unusual type of roof that is rarely seen in cold climates where snow load is a factor.
Butterfly Valve Type of control valve that uses a flat circular plate in the pipe which rotates ninety degrees across the cross section of the pipe to control flow.Back to top
Cantilever A beam that is unsupported at one or both ends. Typically used to support balconies on apartments and some office buildings.
Cantilever collapse This pattern of collapse occurs when one or more walls of a multistory building collapse leaving the floors attached to and supported by the remaining walls.
Carabiner A steel or aluminum D-shaped snap link device for attaching components of rope rescue systems together. They are also called biners, crabs, or snap links.
Carbon Dioxide (CO2) Colorless, odorless, heavier than air gas that neither supports combustion nor burns. CO2 is used in portable fire extinguishers as an extinguishing agent to extinguish Class B or C fires by smothering or displacing the oxygen.
Carbon Monoxide (CO) Colorless, odorless, dangerous gas (both toxic and flammable) formed by the incomplete combustion of carbon. It combines more than 200 times as quickly with hemoglobin as oxygen, thus decreases the blood’s ability to carry oxygen.
Carboxyhemoglobin (COHB) Hemoglobin saturated with carbon monoxide and therefore unable to absorb needed oxygen.
Carcinogen Cancer-producing substance.
Cardiopulmonary Resuscitation (CPR) Application of rescue breathing and external cardiac compression used on patients in cardiac arrest to provide an adequate circulation and oxygen to support life.
Carryall Waterproof carrier or bag used to carry and catch debris or used as a water sump basin for immersing small burning objects.
Casement Window Window hinged along one side, usually designed to swing outward, with the screen on the inside. Also called crank out window.
Catchall Retaining basin, usually made from salvage covers, to impound water dripping from above.
CBRNE Abbreviation for Chemical, Biological, Radiological, Nuclear, and Explosive.
Celsius Scale Temperature scale on which the freezing point is 0 degrees and the boiling point at sea level is 100 degrees. Also known as Centigrade scale.
Central Station Alarm System System that functions through a constantly attended location (central station) operated by an alarm company. Alarm signals from the protected property are received in the central station and are then retransmitted by trained personnel to the fire department alarm communications center.
Chafing Block Blocks placed under hoselines to protect the hose covering from damage due to rubbing against the ground or concrete.
Chain Saw Cutting tool designed for cutting wood; most commonly used as a ventilation tool; useful during natural disasters.
Charged Line Hose loaded with water under pressure and prepared for use.
Cheater A piece of pipe slipped over the handle of a prying tool to lengthen the handle, thus providing additional leverage.
Checkrail Window Type of window usually consisting of two sashes, known as the upper and lower sashes, that meet in the center of the window and may be made of either wood or metal.
Chemical Degradation Process that occurs when the characteristics of a material are altered through contact with chemical substances.
Chemical Flame Inhibition The extinguishment of a fire by interruption of the chemical chain reaction.
Chemical Heat Energy Heat produced from a chemical reaction including combustion, spontaneous heating, heat of decomposition, and heat of solution.
Chemical Protective Clothing (CPC) Clothing designed to shield or isolate individuals from the chemical, physical, and biological hazards that may be encountered during operations involving hazardous materials.
Chimney Effect Created when a ventilation opening is made in the upper portion of a building and air currents throughout the building are drawn in the direction of the opening; also occurs in wildland fires when the fire advances up a V-shaped drainage swale.
Chipboard A wooden structural panel formed by gluing and compressing wood strands together under pressure.
Chord The main structural members of a truss as distinguished from diagonals. Chords span the open space between the upper and lower diagonal members in a truss assembly.
Chronic Marked by long duration; recurring over a period of time.
Churning (1) Movement of smoke being blown out of a ventilation opening only to be drawn back inside by the negative pressure created by the ejector because the open area around the ejector has not been sealed. Also called recirculation. (2) Rotation of a centrifugal pump impeller when no discharge ports are open so that no water flows through the pump.
Chutes—narrow v-shaped ravines Chute Salvage cover arrangement that channels excess water from a building. A modified version can be made with larger sizes of fire hose.
Circular Saw Originally designed for use in construction; especially useful in situations where electrical power is readily available and heavier and bulkier power saws are too difficult to handle.
Circulating Feed Fire hydrant that receives water from two or more directions.
Citizens Band (CB) Radio Low-power radio transceiver that operates on frequencies authorized by the Federal Communications Commission (FCC) for public use with no license requirement.
Clapper Valve Hinged valve that permits the flow of water in one direction only.
Class A Fire Fires involving ordinary combustibles such as wood, paper, cloth, and similar materials.
Class A Foam Foam specially designed for use on Class A combustibles.
Class B Fire Fires of flammable and combustible liquids and gases such as gasoline, kerosene, and propane.
Class B Foam Concentrate Foam fire-suppression agent that is designed for use on un-ignited or ignited Class B flammable or combustible liquids.
Class C Fire Fires involving energized electrical equipment.
Class D Fire Fires of combustible metals such as magnesium, sodium, and titanium.
Class K Fire Fires in cooking appliances that involve combustible cooking media (vegetable or animal oils and fats). Commonly occurring in commercial cooking facilities such as restaurants and institutional kitchens.
Closed-Circuit Breathing Apparatus Respiratory protection system in which the exhalations of the wearer is rebreathed after carbon dioxide has been effectively removed and a suitable oxygen concentration restored from resources composed of compressed oxygen, chemical oxygen, or liquid oxygen; usually long-duration device systems; not approved for fire fighting operations.
Clove Hitch Knot that consists essentially of two half hitches.
CNG Abbreviation for Compressed Natural Gas.
Cockloft An open space between the roof and ceiling of a commercial or industrial building.
Code enforcement Conducted to ensure that citizens have a safe physical environment in which to work, study, worship, or play.
Code of Federal Regulations (CFR) Formal name given to the books or documents containing the specific United States regulations provided for by law. The complete body of U.S. Federal law.
Codes A body of laws arranged systematically usually pertaining to one subject area such as a mechanical code, a building code, an electrical code, or a fire code.
Column A vertical supporting member. Columns may be wooden or steel posts.
Combination Attack Battling a fire by using both a direct and an indirect attack. Attack method that involves moving the water or foam stream around a compartment in an O, T, or Z pattern.
Combination Ladder Ladder that can be used as either a single, extension, or A-frame ladder.
Combination Lay Hose lay in which two or more hoselines are laid in either direction — water source to fire or fire to water source.
Combination Smoke Detector Smoke-sensing device consisting of both photoelectric and ionization smoke detectors.
Combination Spreader/Shears Powered hydraulic tool consisting of two arms equipped with spreader tips that can be used for pulling or pushing. The insides of the arms contain cutting shears.
Combination System Water supply system that is a combination of both gravity and direct pumping systems. It is the most common type of municipal water supply system.
Combustible Liquid Liquid having a flash point at or above 100°F (37.8°C) and below 200°F (93.3°C).
Combustion An exothermic chemical reaction that is a self-sustaining process of rapid oxidation of a fuel, that produces heat and light.
Come-Along Manually operated pulling tool that uses a ratchet/pulley arrangement to provide a mechanical advantage.
Command Post (CP) The designated physical location of the command and control point where the incident commander and command staff function during an incident and where those in charge of emergency units report to be briefed on their respective assignments.
Command (1) Act of directing, ordering, and/or controlling resources by virtue of explicit legal, agency, or delegated authority. (2) Term used on the radio to designate the incident commander. (3) Function of NIMS-ICS that determines the overall strategy of the incident, with input from throughout the ICS structure.
Common fire hazard A condition that is prevalent in almost all occupancies and increases the likelihood of a fire starting.
Common The probable frequency of a hazard being found, not to the severity of the hazard.
Communications Personnel (Telecommunicators) Receive emergency and nonemergency phone calls, process the information, dispatch units, establish and maintain a communications link to in-service companies, and complete incident reports.
Communications/Dispatch Center Telecommunications facility (a building or portion of a building) that is specifically configured for the primary purpose of providing emergency communication services or public safety answering point (PSAP) services to one or more public safety agencies under the authority or authorities having jurisdiction.
Compressed Air Foam System (CAFS) Generic term used to describe a high-energy foam-generation system consisting of an air compressor (or other air source), a water pump, and foam solution that injects air into the foam solution before it enters a hoseline.
Compressed Gas Gas that, at normal temperature, exists solely as a gas when pressurized in a container as opposed to a gas that becomes a liquid when stored under pressure.
Compressed Natural Gas Natural gas that is stored in a vessel at pressures of 2,400 to 3,600 psi (16 800 kPa to 25 200 kPa).
Compression Those vertical and/or horizontal forces that tend to push the mass of a material together. For example, the force exerted on the top chord of a truss.
Conduction Physical flow or transfer of heat energy from one body to another through direct contact or an intervening medium from the point where the heat is produced to another location or from a region of high temperature to a region of low temperature.
Confinement (1) Process of controlling the flow of a spill and capturing it at some specified location. (2) Operations required to prevent fire from extending from the area of origin to uninvolved areas or structures.
Containment Act of stopping the further release of a material from its container.
Contamination Condition of impurity resulting from a mixture or contact with foreign substance. Also see Decontamination and Contaminant.
Convection Transfer of heat by the movement of heated fluids or gases, usually in an upward direction.
Convulsant Poison that causes an exposed individual to have convulsions.
Cooling The act of lowering the temperature of the fuel and adjacent surfaces.
Course Horizontal layer of masonry units. A row of bricks is an example of a course.
CPC Abbreviation for Chemical Protective Clothing.
CPR Abbreviation for Cardiopulmonary Resuscitation.
Cross Contamination Contamination of people, equipment, or the environment outside the hot zone without contacting the primary source of contamination.
Cryogen Gas that is cooled to a very low temperature, usually below -150°F (-101°C), to change to a liquid. Also called refrigerated liquid and cryogenic liquid.
Cryogenic Liquid Gas that is cooled to a very low temperature, usually below -150°F (-101°C), to change to a liquid. Also called refrigerated liquid.
Curtain Board Nonload-bearing interior wall extending down from a roof or ceiling to limit the horizontal spread of fire and heat.
Curtain Wall Nonload-bearing exterior wall used as a weather barrier but not for structural support. On many high-rise buildings, the outside walls (often sheet glass in frames) are curtain walls.
Customer Service Quality of an organization’s relationship with individuals who have contact with the organization.
Cutting Flares Cutting tool used for cutting metal or concrete.Back to top
Dangerous Good (1) Any product, substance, or organism included by its nature or by the regulation in any of the nine United Nations classifications of hazardous materials. (2) Term used to describe hazardous materials in Canada. (3) Term used in the U.S. and Canada for hazardous materials on board aircraft.
Daylight Basement A finished basement with large exterior windows and usually one or more exterior doors.
Dead-End Hydrant Fire hydrant located on a dead-end main that receives water from only one direction.
Decking Planks or panels of plywood or oriented strand board (OSB) that form the substrate of a roof assembly.
Decon Abbreviation for Decontamination.
Decontamination (Decon) Process of removing a hazardous, foreign substance from a person, clothing, or area.
Defensive Strategy Overall plan for incident control established by the Incident Commander (IC) that involves protection of exposures as opposed to aggressive, offensive intervention.
Defusing Informal discussion with incident responders conducted after the incident has been terminated either at the scene or after the units have returned to quarters.
Demobilization Unit Functional unit within the planning section of an incident management system; responsible for assuring orderly, safe, and efficient demobilization of resources committed to the incident.
Department of Transportation (DOT) Administrative body of the executive branch of the state/provincial or federal government responsible for transportation policy, regulation, and enforcement.
Dewatering Process of removing water from a vessel.
Dilution Application of water to a water-soluble material to reduce the hazard.
Direct Attack (Structural) Attack method that involves the discharge of water or a foam stream directly onto the burning fuel.
Direct Attack (Wildland) Operation where action is taken directly on burning fuels by applying an extinguishing agent to the edge of the fire or close to it.
Direct Pumping System Water supply system supplied directly by a system of pumps rather than elevated storage tanks.
Directive Authoritative instrument or order issued by a superior officer.
Discipline To maintain order through training and/or the threat or imposition of sanctions; setting the limits or boundaries for expected performance and enforcing them.
Dispatcher Person who works in the communications center and processes information from the public and emergency responders.
Dissolution Act or process of dissolving one thing into another; process of dissolving a gas in water.
Distributors Grid arrangement of smaller mains serving individual fire hydrants and blocks of consumers.
Division of Labor Breaking down an assignment into its constituent parts in order to equalize the workload and increase efficiency.
Division IMS organizational level having responsibility for operations within a defined geographic area. It is composed of a number of individual units that are assigned to operate within a defined geographical area.
Dogs Devices attached to the inside of the beams on fly sections used to hold the fly section in place after it has been extended.
Dome Roof Hemispherical roof assembly, usually supported only at the outer walls of a circular or many-sided structure.
Donut Roll Length of hose rolled up for storage and transport.
Double-Hung Window Window having two vertically moving sashes.
Draft Process of acquiring water from a static source and transferring it into a pump that is above the source’s level; atmospheric pressure on the water surface forces the water into the pump where a partial vacuum was created.
Drop Bar Metal or wooden bar that serves as a locking device when placed or dropped into brackets across a swinging door.
Dry Chemical Any one of a number of powdery extinguishing agents used to extinguish fires. The most common include sodium or potassium bicarbonate, monoammonium phosphate, or potassium chloride.
Dry Powder Extinguishing agent suitable for use on combustible metal fires.
Dry-Barrel Hydrant Fire hydrant that has its operating valve at the water main rather than in the barrel of the hydrant.
Drywall Gypsum wall board. A fire resistive wall covering also called sheetrock™.
Duck-billed Lock Breaker A wedge-shaped tool that will widen and break the shackles of padlocks.
Dutchman Extra fold placed along the length of a section of hose as it is loaded so that its coupling rests in proper position.
Dynamic The amount of stretch built into a rope. Dynamic ropes have a large amount of stretch, in order to reduce the shock on the climber and anchor systems. They are used for recreational climbing, where long falls may occur.Back to top
Eave The edge of a pitched roof that overhangs an outside wall. Attic vents in typical eaves provide an avenue for an exterior fire to enter the attic.
EDITH Abbreviation for Exit Drills In The Home
Education Process of teaching, instructing, or training individuals in new skills or additional knowledge or preparing individuals for some kind of action or activity. What teachers do to bring about learning in their students. It may or may not involve formal classroom instruction.
Eductor (Inductor) (1) Portable proportioning device that injects a liquid, such as foam concentrate, into the water flowing through a hoseline or pipe. (2) Syphon used to remove water from flooded basements. (3) Venturi device that uses water pressure to draw foam concentrate into a water stream for mixing; also enables a pump to draw water from an auxiliary source.
Electrical Heat Energy Heat energy that is electrical in origin including resistance heating, dielectric heating, heat from arcing, and heat from static electricity.
Emergency Decontamination Removing contamination on individuals in potentially life-threatening situations with or without the formal establishment of a decontamination corridor.
Emergency Escape Breathing Support System (EEBSS) Safety system on an SCBA that allows two units to be hooked together in the event that one fails.
Emergency Medical Services (EMS) Initial medical evaluation/treatment provided to employees and others who become ill or are injured in the workplace.
Emergency Medical Technician (EMT) Professional-level provider of basic life support emergency medical care. Requires certification by some authority.
Emergency medical/Ambulance Company Provides emergency medical care to patients (may provide transportation to a medical facility)
Emergency Response Guidebook (ERG) Guide developed jointly by Transport Canada (TC), U.S. Department of Transportation (DOT), and the Secretariat of Transport and Communications of Mexico (SCT) for use by firefighters, police, and other emergency services personnel who may be the first to arrive at the scene of a transportation incident involving dangerous goods.
Emergency Traffic Urgent radio traffic; a request for other unit to clear the radio waves for an urgent message. Also called Priority Traffic.
Emergency A situation that is emerging – in other words, it is not staying the same – it is getting bigger or getting worse.
Employee Assistance Program (EAP) Any one of many programs that may be provided by an employer to employees and their families to aid in solving work or personal problems.
Endothermic Heat Reaction Chemical reaction in which a substance absorbs heat energy.
Energy The capacity to perform work
Engine Company Group of firefighters assigned to a fire department pumper who are primarily responsible for providing water supply and attack lines for fire extinguishment.
Engineered I-beam A wooden I-beam consisting of continuous wooden upper and lower chords separated by a web of OSB or similar sheet stock.
Entry Point (Entry Opening) Ventilation opening through which replacement air enters the structure.
Environmental Protection Agency (EPA) U.S. government agency that creates and enforces laws designed to protect the air, water, and soil from contamination; responsible for researching and setting national standards for a variety of environmental programs.
Evacuation Process of leaving or being removed from a potentially hazardous location. Also see Shelter in Place.
Evaporation Process of a solid or a liquid turning into gas.
Evidence In law, something legally presented in court that bears on the point in question. Information collected and analyzed by an investigator.
Exothermic Chemical reaction between two or more materials that changes the materials and produces heat, flames, and toxic smoke.
Expansion-ring gasket Expansion Ring Malleable metal band that binds fire hose to a threaded coupling by compressing the hose tightly against the inner surface of the coupling.
Explosive Any material or mixture that will undergo an extremely fast, self-propagation reaction when subjected to some form of energy. Material capable of burning or bursting suddenly and violently.
Exposure Structure or separate part of the fireground to which a fire could spread. People, properties, systems, or natural features that are or may be exposed to the harmful effects of a hazardous materials emergency.
Extension Ladder Sectional ladder of two or more parts that can be extended to various heights.
Extension Ram Powered, hydraulic tool designed especially for straight pushing operations that may extend as far as 63 inches (1 600 mm).
Extrication Incidents involving the removal and treatment of victims who are trapped by some type of man-made machinery or equipment.Back to top
Fahrenheit Scale Temperature scale on which the freezing point is 32°F (0°C) and the boiling point at sea level is 212°F (100°C) at normal atmospheric pressure.
Fax To send a hard copy facsimile (copy) of print or illustrative material via the telephone lines.
FCC Abbreviation for Federal Communication Commission.
Federal Communications Commission (FCC) U.S. government agency charged with the control of all radio and television communications. Acts as the main regulator of radio frequencies in the United States in both the public and private sector.
Feed Main Pipe connecting the sprinkler system riser to the cross mains.
Female Coupling Threaded swivel device on a hose or appliance with internal threads designed to receive a male coupling having external threads of the same thread and diameter.
Figure-Eight Forged metal device in the shape of an eight; used to help control the speed of a person descending a rope.
Figure-Eight Knot Knot used to form a loop in the end of a rope; should be used in place of the bowline knot when working with synthetic fiber rope.
Film Forming Fluoroprotein Foam (FFFP) Foam concentrate that combines the qualities of fluoroprotein foam with those of aqueous film forming foam.
Finance/Administration Section Chief (Finance) Established when the agencies involved require finance and other administrative support services.
Finance/Administrative Unit Component of IMS responsible for documenting the ongoing financial impact of the incident. This function oversees the documentation of time and costs associated with personnel, as well as the documentation of private resources used throughout the incident.
Finger(s) Long, narrow extension(s) of a fire projecting from the main body of a natural cover fire.
Finish Arrangement of hose usually placed on top of a hose load and connected to the end of the load.
Fire Rapid oxidation of combustible materials accompanied by a release of energy in the form of heat and light.
Fire Alarm (1) Call announcing a fire. (2) Bell or other device summoning a fire company to respond to a fire or other emergency.
Fire Alarm Maintenance Personnel Maintain municipal fire alarm systems.
Fire and Arson Investigator Investigates fires and makes analytical judgments based on the physical evidence at the fire scene to determine the origin and cause of a fire.
Fire Apparatus Driver/Operator Firefighter who is charged with the responsibility of operating fire apparatus to, during, and from the scene of a fire operation or any other time the apparatus is in use.
Fire Department Connection (FDC) Point at which the fire department can connect into a sprinkler or standpipe system to boost the water flow in the system. This connection consists of a clappered siamese with two or more 2½-inch (65 mm) intakes or one large-diameter (4-inch [100 mm] or larger) intake.
Fire Department Officer May fulfill any of the following responsibilities, depending upon the size and structure of the fire department: The fire chief is ultimately responsible for all operations within the fire department, including obtaining the funds needed to carry out its mission. Fire department officers supervise a fire company in the station and at fires and other emergencies. They may also supervise a group of fire companies in a specified geographical region of the city. Other roles assigned include operations, training, personnel/administration, public information, fire prevention, resources, and planning.
Fire Door A specially constructed, tested, and approved fire-rated door assembly designed and installed to prevent fire spread by automatically closing and covering a doorway in a fire wall during a fire to block the spread of fire through the door opening.
Fire Edge Boundary of a fire at a given moment.
Fire Growth The formation of a fire plume above the burning fuel after ignition.
Fire Hazard Any material, condition, or act that contributes to the start of a fire or that increases the extent or severity of fire.
Fire Hose A type of flexible tube used by firefighters to carry water or other extinguishing agents under pressure from a source of supply to a point of application.
Fire Inspector Fire personnel assigned to inspect property with the purpose of enforcing fire regulations.
Fire Load Total potential heat release if a building and its contents burned.
Fire Marshal Highest fire prevention officer of a state, province, county, or municipality. In Canada, this officer is sometimes called the fire commissioner.
Fire Point Temperature at which a liquid fuel produces sufficient vapors to support combustion once the fuel is ignited. The fire point is usually a few degrees above the flash point.
Fire Police Personnel Assist law enforcement officers with traffic control, crowd control, and scene security at fires and other emergency operations
Fire Prevention Bureau Division of the fire department responsible for conducting fire prevention programs of inspection, code enforcement, education, and investigation.
Fire Prevention (1) Part of the science of fire protection that deals with preventing the outbreak of fire by eliminating fire hazards through such activities as inspection, code enforcement, education, and investigation programs. (2) Division of a fire department responsible for conducting fire prevention programs of inspection, code enforcement, education, and investigation.
Fire Protection Engineer/Specialist Checks plans for proposed buildings to ensure compliance with local fire and life safety codes and ordinances; acts as a consultant to the fire department administration in the areas of fire department operations and fire prevention.
Fire Resistant Capacity of structural components to resist higher heat temperatures for certain periods of time. Lesser degree of resistance to fire than "fireproof."
Fire Stream Stream of water or other water-based extinguishing agent after it leaves the fire hose and nozzle until it reaches the desired point.
Fire Tetrahedron Model of the four elements/conditions required to have a fire. The four sides of the tetrahedron represent fuel, heat, oxygen, and chemical chain reaction.
Fire Triangle The sides of the triangle represent heat, oxygen, and fuel. The fire triangle was used prior to the general adaptation of the fire tetrahedron that includes a chemical chain reaction.
Fire Wall A rated assembly that extends from the foundation to and through the roof of a building to limit fire spread.
Fire-Gas Detector Device used to detect gases produced by a fire within a confined space.
Fire-resistive Construciton--Type I Construction Type I construction has structural members, including walls, columns, beam, floors, and roofs, that are made of noncombustible materials or limited combustible materials and have a specified degree of fire resistance. Formerly referred to as fire resistive construction.
First Responder (EMS) (1) First person arriving at the scene of an accident or medical emergency who is trained to administer first aid and basic life support. (2) Level of emergency medical training, between first aider and emergency medical technician levels, that is recognized by the authority having jurisdiction.
First-Due Apparatus that should reach the scene of an emergency first based on the pre-fire attack plan. Also referred to as First-In.
Fitting Device that facilitates the connection of hoselines of different sizes to provide an uninterrupted flow of extinguishing agent.
Fixed-Temperature Heat Detector Temperature-sensitive device that senses temperature changes and sounds an alarm at a specific point, usually 135°F (57°C) or higher.
Flame Detectors Detection and alarm devices used in some fire detection systems (generally in high-hazard areas) that detect light/flames in the ultraviolet wave spectrum (UV detectors) or detect light in the infrared wave spectrum (IR detectors).
Flameover Condition that occurs when a portion of the fire gases trapped at the upper level of a room ignite, spreading flame across the ceiling of the room.
Flammable Liquid Any liquid having a flash point below 100°F (37.8°C) and having a vapor pressure not exceeding 40 psi absolute (276 kPa).
Flammable Range The range between the upper flammable limit and lower flammable limit in which a substance can be ignited. Also called Explosive Range.
Flank Sides of a natural cover fire.
Flash Point Minimum temperature at which a liquid gives off enough vapors to form an ignitable mixture with air near the liquid’s surface.
Flashback Spontaneous reignition of fuel when the blanket of extinguishing agent breaks down or is compromised through physical disturbance.
Flashover Stage of a fire at which all surfaces and objects within a space have been heated to their ignition temperature and flame breaks out almost at once over the surface of all objects in the space.
Flat Load Arrangement of fire hose in a hose bed or compartment in which the hose lies flat with successive layers one upon the other.
Flat Roof A roof that is flat or nearly flat relative to the horizon. Many commercial buildings have flat roofs covered with tar and gravel or other weatherproof material.
Flat-Head Axe Axe with a cutting edge on one side of the head and a blunt or flat head on the opposite side.
Floor Runner Heavy plastic or canvas placed on a floor to protect the floor’s surface or covering from firefighter traffic; used during salvage operations.
Flow Pressure Pressure created by the rate of flow or velocity of water coming from a discharge opening.
Fly Section Extendable section of ground extension or aerial ladder. Also referred to as Fly.
Foam Extinguishing agent formed by mixing a foam concentrate with water and aerating the solution for expansion; for use on Class A and Class B fires. Foam may be protein, synthetic, aqueous film forming, high expansion, or alcohol type.
Foam Concentrate Raw chemical compound solution that is mixed with water and air to produce foam.
Foam Proportioner Device that injects the correct amount of foam concentrate into the water stream to make the foam solution.
Foam Solution Result of mixing the appropriate amount of foam concentrate with water. Foam solution exists between the proportioner and the nozzle or aerating device that adds air to create finished foam.
Fog Nozzle Nozzle that can provide either a fixed or variable spray pattern. The nozzle breaks the foam solution into small droplets that mix with air to form finished foam.
Fog Stream Water stream of finely divided particles used for fire control.
Folding Ladder Short, collapsible ladder easy to maneuver in tight places such as reaching through openings in attics and lofts.
Foot Pads Feet mounted on the butt of the ladder by a swivel to facilitate the placement of ladders on hard surfaces.
Forced Ventilation Any means other than natural ventilation. This type of ventilation may involve the use of fans, blowers, smoke ejectors, and fire streams.
Forcible Entry Techniques used by fire personnel to gain entry into buildings, vehicles, aircraft, or other areas of confinement when normal means of entry are locked or blocked.
Forward Lay Method of laying hose from the water supply to the fire scene.
Four-Way Hydrant Valve Device that permits a pumper to boost the pressure in a supply line connected to a hydrant without interrupting the water flow.
Frangible Bulb Small glass vial fitted into the discharge orifice of a fire sprinkler.
Friction Loss That part of the total pressure lost as water moves through a hose or piping system, caused by water turbulence and the roughness of interior surfaces of hose or pipe.
Fuel Flammable and combustible substances available for a fire to consume.
Fuel moisture content Fuel Moisture Quantity of moisture in fuel expressed as a percentage of the weight when thoroughly dried at 212°F (100°C).
Fully Developed Fire Occurs when all combustible materials in a compartment are involved in fire.
Fully developed stage Occurs when all combustible materials in the compartment are burning.
Fusible Link Connecting link device that fuses or melts when exposed to heat. Used in sprinklers, fire doors, dampers, and ventilators.Back to top
Gable Roof A pitched roof characterized by square-cut ends and sides that slope down from the ridge line to the eaves.
Gable Wall A wall rising to meet a gable roof at the end of a building. These walls are found only at the ends of gable roofs and they often include an attic vent near the top of the wall.
Gabled Roof Style of pitched roof with square ends in which the end walls of the building form triangular areas beneath the roof.
Gambrel Roof A roof characterized by a single ridge line from which roof sections on both sides of the ridge descend at two different pitches.
Gamma Radiation Very high-energy ionizing radiation composed of gamma rays.
Gang Nail Form of gusset plate.
Gas Compressible substance, with no specific volume, that tends to assume the shape of a container. Molecules move about most rapidly in this state.
Gate Valve Control valve with a solid plate operated by a handle and screw mechanism. Rotating the handle moves the plate into or out of the waterway.
Gated Wye Hose appliance with one female inlet and two or more male outlets with a gate valve on each outlet.
Generator Auxiliary electrical power generating device. Portable generators are powered by small gasoline or diesel engines and generally have 110- and/or 220-volt capacities.
Girder A horizontal structural member used to support beams or joists. Girders are almost always of larger dimension than the members they support.
GIS Abbreviation for Graphical Information System.
Global Positioning System (GPS) System for determining a position on the earth’s surface by calculating the difference in time for the signal from a number of satellites to reach a receiver on the ground.
Gloves Part of the firefighter’s protective clothing ensemble necessary to protect the hands.
Glue-Lam Beam A wooden structural member composed of relatively short pieces of lumber glued and laminated together under pressure to form a long, extremely strong beam. Because of the mass of most glue-lam beams, they resist fire extremely well compared to other materials.
GOG Abbreviation for General Operating Guideline.
GPS Abbreviation for Global Positioning System.
Gravity System Water supply system that relies entirely on the force of gravity to create pressure and cause water to flow through the system. The water supply, which is often an elevated tank, is at a higher level than the system.
Green Area of unburned fuels, not necessarily green in color, adjacent to but not involved in a wildland fire.
Grid System Water supply system that utilizes lateral feeders for improved distribution.
Ground Gradient When an energized electrical wire comes in contact with the ground, current flows outward in all directions from the point of contact. As the current flows away from the point of contact, the voltage drops progressively.
Group IMS organizational subunit responsible for a number of individual units that are assigned to perform a particular specified function at an incident (ventilation, salvage, water supply, etc.).
Grow Ops Clandestine drug labs and indoor marijuana-growing operations
Guides Devices to hold sections of an extension ladder together while allowing free movement.
Gusset Plates Metal or wooden plates used to connect and strengthen the intersections of metal or wooden truss components of roof or floor components into a load-bearing unit.
Gypsum Board Interior finish material consisting of calcinated gypsum, starch, water and other additives sandwiched between two sheets of specially treated paper.
Gypsum Hydrated calcium sulfate used for gypsum plaster and wallboard.
Gyroscopic Effect (Torsion Effect) Twisting caused by the spinning blade of a rotary saw.Back to top
Half Hitch Knot that is always used in conjunction with another knot.
Halogenated Agents Chemical compounds (halogenated hydrocarbons) that contain carbon plus one or more elements from the halogen series.
Halon Halogenated agent; extinguishes fire by inhibiting the chemical reaction between fuel and oxygen.
Halyard Rope used on extension ladders to extend the fly sections. Also called Fly Rope.
Handline Nozzle Any nozzle that can be safely handled by one to three firefighters and flows less than 350 gpm (1 400 L/min).
Handsaw A saw that is operated by hand rather than a power source.
Hard Suction Hose A flexible rubber hose reinforced with a steel core to prevent collapse from atmospheric pressure when drafting; connected between the intake of a fire pump and a water supply and must be used when drafting.
Hazard Area Established area from which bystanders and unneeded rescue workers are prohibited.
Hazard-Control Zones System of barriers surrounding designated areas at emergency scenes intended to limit the number of persons exposed to a hazard and to facilitate its mitigation; major incident has three zones: restricted (hot), limited access (warm), and support (cold).
Hazardous Material Any substance or material that possesses an unreasonable risk to health and safety of persons and/or the environment if it is not properly controlled during handling, storage, manufacture, processing, packaging, use, disposal, or transportation.
Hazardous Materials Company Any piece of equipment having the capabilities, PPE, equipment, and complement of personnel as specified in the Hazardous Materials Company Types and Minimum.
Hazardous Materials Technician Handles hazardous materials and radiological, nuclear, biological, and chemical (RNBC) emergencies.
Hazardous Waste Operations and Emergency Response (HAZWOPER) U.S. regulations in Title 29 (Labor) CFR 1910.120 for cleanup operations involving hazardous substances and emergency response operations for releases of hazardous substances.
Head (1) Front and rear closure of a tank shell. (2) Alternate term for pressure, especially pressure due to elevation. For every 1-foot increase in elevation, 0.434 psi is gained (for every 1-meter increase in elevation, 9.82 kPa is gained). Also called Head Pressure. (3) Top of a window or door frame. (4) Most active part of a ground cover fire; the forward advancing part.
Header Course Course of bricks laid with the ends facing outward. Because the ends of the bricks are smaller than the sides, a header course is easy to identify.
Health and Safety Officer (HSO) Member of the fire and emergency services organization who is assigned and authorized by the administration as the manager of the health and safety program and performs the duties, functions, and responsibilities in NFPA 1521, Standard for Fire Department Safety Officer.
Heat Cramps Heat illness resulting from prolonged exposure to high temperatures; characterized by excessive sweating, muscle cramps in the abdomen and legs, faintness, dizziness, and exhaustion.
Heat Detector Alarm-initiating device that is designed to be responsive to a predetermined rate of temperature increase or to a predetermined temperature level.
Heat Exhaustion Heat illness caused by exposure to excessive heat; symptoms include weakness, cold and clammy skin, heavy perspiration, rapid and shallow breathing, weak pulse, dizziness, and sometimes unconsciousness.
Heat Hole A large ventilation opening cut between a trench cut and the fire.
Heat of Combustion Total amount of thermal energy (heat) that could be generated by the combustion (oxidation) reaction if a fuel were completely burned. The heat of combustion is measured in British Thermal Units (Btu) per pound or calories per gram.
Heat of compression Generated when a gas is compressed.
Heat of Friction Heat created by the movement of two surfaces against each other.
Heat Rash Condition that develops from continuous exposure to heat and humid air; aggravated by clothing that rubs the skin; reduces an individual's tolerance to heat.
Heat Release Rate (HRR) Total amount of heat produced or released to the atmosphere from the convective-lift fire phase of a fire per unit mass of fuel consumed per unit time.
Heat Sensor Label Label affixed to the ladder beam near the tip to provide a warning that the ladder has been subjected to excessive heat.
Heat Stratification Outcome of combustion in a confined space in which gases tend to form into layers, according to temperature, with the hottest gases are found at the ceiling and the coolest gases at floor level.
Heat Stroke Heat illness caused by heat exposure, resulting in failure of the body's heat regulating mechanism; symptoms include (a) high fever of 105 to 106°F (40.5°C to 41.1°C), (b) dry, red, and hot skin, (c) rapid, strong pulse, and (d) deep breaths or convulsions; may result in coma or possibly death.
Heavy Timber Construction--Type IV Construction Heavy timber construction features exterior and interior walls and their associated structural members that are of noncombustible or limited combustible materials. Formerly referred to as heavy timber construction.
Heel (1) Base or butt end of a ground ladder. (2) To steady a ladder while it is being raised. (3) Rear portion of a wildland fire. Also called Rear. (4) Angle a vessel leans to one side due to wind, waves, or turning of the vessel; measured in degrees.
Heeler The firefighter at the butt end of the ladder responsible for placing it at the desired distance from the building and determining whether the ladder will be raised parallel with or perpendicular to the building.
Heeling (1) Tipping or leaning to one side. (2) Causing a vessel to list (continuous lean to one side).
Helmet Protective headgear worn by firefighters that provides protection from falling objects, side blows, the fire environment elements, and eye injuries.
HEPA Acronym for High Efficiency Particulate Air.
Higbee Cut Special cut at the beginning of the thread on a hose coupling that provides positive identification of the first thread to eliminate cross threading.
Higbee Indicators Notches or grooves cut into coupling lugs to identify by touch or sight the exact location of the Higbee Cut.
High-Expansion Foam Foam concentrate that is mixed with air in the range of 200 parts air to 1 part foam solution (200:1) to 1,000 parts air to 1 part foam solution (1,000:1).
High-pressure Pneumatic Lifting Bags Consists of a tough, neoprene rubber exterior reinforced with steel wire or Kevlar™ aramid fiber.
High-Rise/High-Rise Building Any building that requires fire fighting on levels above the reach of the department’s equipment; defined in some building codes as any building of more than 75 feet (23 m) in height.
Hip Roof A pitched roof in which the ends are all beveled so that there are no gable walls.
Hooks Curved metal devices installed on the tip end of roof ladders to secure the ladder to the highest point on the roof of a building.
Horizontal Ventilation Any technique by which heat, smoke, and other products of combustion are channeled horizontally out of a structure by way of existing or created horizontal openings such as windows, doors, or other holes in walls.
Horseshoe Load Arrangement of fire hose in a hose bed or compartment in which the hose lies on edge in the form of a horseshoe.
Hose Bed Main hose-carrying area of a pumper or other piece of apparatus designed for carrying hose.
Hose Bridge Device placed alongside or astride hose that is laid across a street to permit traffic to drive over the hose without damaging it.
Hose Cap Threaded female fitting used to cap a hoseline or a pump outlet.
Hose Clamp Mechanical or hydraulic device used to compress a fire hose to stop the flow of water.
Hose Hoist Metal device having a roller that can be placed over a windowsill or roof’s edge to protect a hose and make it easier to hoist.
Hose Jacket (1) Outer covering of a hose. (2) Device clamped over a hose to contain water at a rupture point or to join hose with damaged or dissimilar couplings.
Hose Plug Threaded male fitting used to cap off a pump intake.
Hose Ramp Device placed alongside or astride hose that is laid across a street to permit traffic to drive over the hose without damaging it.
Hose Roller Metal device having a roller that can be placed over a windowsill or roof’s edge to protect a hose and make it easier to hoist.
Hose Strap Strap or chain with a handle suitable for placing over a ladder rung; used to carry and secure a hoseline.
Hot Smoldering Phase Phase or stage of fire in which the level of oxygen in a confined space is below that needed for flaming combustion; characterized by glowing embers, high heat at all levels of the room, and heavy smoke and fire gas production. Also called the Decay stage.
Hurricane Window A window designed to resist hurricane-force winds.
HVAC Abbreviation for heating, ventilating, and air conditioning.
HVAC System Abbreviation for Heating, Ventilating, and Air-Conditioning System. (1) The mechanical system used to provide environmental control within a structure. (2) Air-handling system within a building consisting of fans, ducts, dampers, and other equipment necessary to make it function.
Hydrant Wrench Specially designed tool used to open or close a hydrant and to remove hydrant caps.
Hydraulic Jack Lifting jack that uses hydraulic fluid power supplied from a manually operated hand lever.
Hydraulic Prying Tools Can be either powered hydraulic or manual hydraulic, both types receive their power from hydraulic fluid pumped through special high-pressure hoses.
Hydraulic Ventilation Method of ventilating a fire building by directing a fog stream of water out a window to increase air and smoke movement.
Hydrocarbon Fuel Petroleum-based organic compound that contains only hydrogen and carbon.
Hydrogen Cyanide (HCN) Colorless, toxic gas with a faint odor similar to bitter almonds; produced by the combustion of nitrogen-bearing substances.
Hypoxia Condition caused by a deficiency in the amount of oxygen reaching body tissues.Back to top
IAP Abbreviation for Incident Action Plan.
IC Abbreviation for Incident Commander.
ICS Abbreviation for Incident Command System.
IDLH Abbreviation for Immediately Dangerous to Life or Health.
IED Abbreviation for Improvised Explosive Device.
Ignition Beginning of flame propagation or burning; the start of a fire.
Immediately Dangerous to Life and Health (IDLH) Any atmosphere that poses an immediate hazard to life or produces immediate irreversible, debilitating effects on health.
Impact Hammer Pneumatic chisel is useful for extrication work; designed to operate at air pressures between 100 and 150 psi (700 kPa and 1 050 kPa).
Improvised Explosive Device (IED) Device that is categorized by its container and the way it is initiated; usually homemade, constructed for a specific target, and contained in almost anything.
Incendiary (1) An incendiary agent such as a bomb. (2) A fire deliberately set under circumstances in which the responsible party knows it should not be ignited. (3) Relating to or involving a deliberate burning of property.
Incident Action Plan (IAP) Written or unwritten plan for the disposition of an incident. The IAP contains the overall strategic goals, tactical objectives, and support requirements for a given operational period during an incident.
Incident Commander (IC) Person in charge of the incident management system and responsible for the management of all incident operations during an emergency.
Incident Investigation Act of investigating or gathering data to determine the factors that contributed to a fatality, injury, or property loss or to determine fire cause and origin.
Incident Safety Officer (ISO) Member of the Command Staff responsible for monitoring and assessing safety hazards and unsafe conditions during an incident, and developing measures for ensuring personnel safety.
Incipient Stage Fire Fire that is in the initial or beginning stage and that can be controlled or extinguished by portable fire extinguishers or small hoselines and without the need to wear protective clothing or breathing apparatus or to take evasive action such as crawling to avoid smoke.
Indicating Valve Water main valve that visually shows the open or closed status of the valve.
Indirect Attack (Structural) Directing fire streams toward the ceiling of a room or building in order to generate a large amount of steam.
Indirect Attack (Wildland) Method of controlling a wildland fire where a control line is constructed or located some distance from the edge of the main fire and the fuel between the two points is burned.
Induction (1) Portable proportioning device that injects a liquid, such as foam concentrate, into the water flowing through a hoseline or pipe. (2) Syphon used to remove water from flooded basements. (3) Venturi device that uses water pressure to draw foam concentrate into a water stream for mixing; also enables a pump to draw water from an auxiliary source.
Industrial Occupancy Industrial, commercial, mercantile, warehouse, utility power station, and institutional or similar facilities.
Information Systems Personnel Manage the collection, entry, storage, retrieval, and dissemination of electronic databases such as fire reporting.
Information/Intelligence Function (Intel) When required, this unit is responsible for analyzing and sharing incident information and intelligence.
Ingestion Taking in food or other substances through the mouth.
Inhalation Taking in materials by breathing through the nose or mouth.
Initial Isolation Distance Distance within which all persons are considered for evacuation in all directions from a hazardous materials incident.
Initial Isolation Zone Circular zone (with a radius equivalent to the initial isolation distance) within which persons may be exposed to dangerous concentrations upwind of the source and may be exposed to life-threatening concentrations downwind of the source.
Injection Method of proportioning foam that uses an external pump or head pressure to force foam concentrate into the fire stream at the correct ratio for the flow desired.
In-Line Eductor Eductor that is placed along the length of a hoseline.
Inspection Formal examination of an occupancy and its associated uses or processes to determine its compliance with the fire and life safety codes and standards.
Instructor Individual deemed qualified by the authority having jurisdiction to deliver instruction and training in fire and emergency services and charged with the responsibility to conduct the class, direct the instructional process, teach skills, impart new information, lead discussions, and cause learning to take place.
Intake Hose Hose used to connect a fire department pumper or a portable pump to a nearby water source. It may be soft sleeve or hard suction hose.
Inverter Auxiliary electrical power generating device. The inverter is a step-up transformer that converts the vehicle’s 12- or 24-volt DC current into 110- or 220-volt AC current.
Ionization Detector Type of smoke detector that uses a small amount of radioactive material to make the air within a sensing chamber conduct electricity.
Ionizing Radiation Radiation that has sufficient energy to remove electrons from atoms resulting in a chemical change in the atom.
Island Unburned area within a fire perimeter.
Isolation Perimeter Outer boundary of an incident that is controlled to prevent entrance by the public or unauthorized persons.Back to top
Jalousie Window Window consisting of narrow, frameless, glass panes set in metal brackets at each end that allow the panes a limited amount of axial rotation for ventilation.
Jet-Assist Device A siphon used to transfer water from one portable tank to another.
J-Hook Designed to be driven into walls or wooden framing to provide a stronger point from when to hang things.
Joists Horizontal structural members used to support a floor or ceiling. Ceiling joists are what drywall materials are nailed or screwed to, and floor joists are what the subfloor is nailed or screwed to.
Joule (J) Unit of work or energy in the International System of Units; the energy (or work) when unit force (1 newton) moves a body through a unit distance (1 meter); takes the place of calorie for heat measurement (1 calorie = 4.19 J).
J-Tool A device made of rigid, heavy gauge wire and designed to fit through the space between double-swinging doors equipped with panic hardware.
Jurisdiction (1) Legal authority to operate or function. (2) Boundaries of a legally constituted entity.Back to top
Kernmantle Rope Rope that consists of a protective shield (mantle) over the load-bearing core strands (kern).
Kinetic Energy The energy possessed by a moving object.
Knot Term used for tying a rope around itself.
K-Tool V-blade tool that is designed to pull lock cylinders from a door with only minimal damage to the door itself.Back to top
Ladder Company Group of firefighters assigned to a fire department apparatus equipped with a compliment of ladders who are primarily responsible for search and rescue, ventilation, salvage and overhaul, forcible entry, and other fireground support functions. Also called Truck Company.
Laid Rope Rope constructed by twisting several groups of individual strands together.
Lamella Arch An arch constructed of short wooden members connected in a specific geometric pattern.
Lapping (Exterior Flame Spread) Means by which fire spreads vertically from floor to floor in a multistory building.
Large Diameter Hose (LDH) Relay-supply hose of 3½ to 6 inches (90 mm to 150 mm) in diameter; used to move large volumes of water quickly with a minimum number of pumpers and personnel.
Large Handline Fire hose/nozzle assembly capable of flowing up to 300 gpm (1 140 l/min).
LC50 Abbreviation for Lethal Concentration.
LD50 Abbreviation for Lethal Dose.
Lean-to Collapse Type of structural collapse where one end of a floor or roof section support fails while the other end remains secured to a wall. The floors and roof drop in large sections and form voids.
Ledge Door Door constructed of individual boards joined within a frame.
Leeward Protected side; the direction opposite from which the wind is blowing.
LERP Abbreviation for Local Emergency Response Plan.
Lethal Concentration (LC50) Concentration of an inhaled substance that results in the death of 50 percent of the test population; the lower the value the more toxic the substance; an inhalation exposure expressed in parts per million (ppm), milligrams per liter (mg/liter), or milligrams per cubic meter (mg/m3).
Lethal Dose (LD50) Concentration of an ingested or injected substance that results in the death of 50 percent of the test population; the lower the dose the more toxic the substance; an oral or dermal exposure expressed in milligrams per kilogram (mg/kg).
Lexan® Polycarbonate plastic used for windows. It has one-half the weight of an equivalent-sized piece of glass, yet is 30 times stronger than safety glass and 250 times stronger than ordinary glass.
Liaison Officer (LNO) Point of contact for assisting or coordinating agencies; member of the command staff.
Life Safety Rope Rope that meets the requirements of nfpa 1983, Standard on Fire Service Life Safety Rope, Harness, and Hardware, and is dedicated solely for the purpose of constructing lines to be used for the raising, lowering, or supporting people during rescue firefighting or other emergency operations, or during training. Also called lifeline.
Life Safety Refers to the joint consideration of the life and physical well-being of individuals, both civilians and firefighters.
Lightweight Steel Truss Structural support made from a long steel bar that is bent at a 90-degree angle with flat or angular pieces welded to the top and bottom.
Lightweight Wood Truss Structural supports constructed of 2- ¥ 3-inch or 2- ¥ 4-inch (50 mm by 75 mm or 50 mm by 100 mm) members that are connected by gusset plates.
Liquefied petroleum gas (LPG) Liquefied Gas A confined gas that at normal temperatures exists in both liquid and gaseous states. See Liquefied Compressed Gases.
Local Alarm Systems (1) Alarm systems that alert and notify only occupants on the premises of the existence of a fire so that they can safely exit the building and call the fire department. If a response by a public safety agency (police or fire department) is required, an occupant hearing the alarm must notify the agency.
Local Emergency Response Plan (LERP) Plan required by U.S. Environmental Protection Agency (EPA) that is prepared by the Local Emergency Planning Committee (LEPC) detailing how local emergency response agencies will respond to community emergencies.
Lock (1) Device for fastening, joining, or engaging two or more objects together such as a door and frame. (2) Also see Pawls.
Logistics Section Chief (Logistics) Responsible for all support requirements needed to facilitate effective and efficient incident management.
Loop System Water main arranged in a complete circuit so that water will be supplied to a given point from more than one direction. Also called circle system, circulating system, or belt system.
Loss Control The practice of minimizing damage and providing customer service through effective mitigation and recovery efforts before, during, and after an incident.
Lower Flammable Limit (LFL) Lower limit at which a flammable gas or vapor will ignite; below this limit the gas or vapor is too lean or thin to burn (too much oxygen and not enough gas).
Low-pressure Pneumatic Lifting Bags Considerably larger than high-pressure bags and are most commonly used to lift or stabilize large vehicles or objects.Back to top
Main Section Bottom section of and extension ladder.
Mains A network of underground pipes.
Maintenance Keeping equipment or apparatus in a state of usefulness or readiness.
Male Coupling Hose coupling with external threads that fit into the threads of a female coupling of the same pitch and appropriate diameter and thread count.
Management of Domestic Incidents Homeland Security Directive-5 Mission of the Fire Service.
Manifold (1) Hose appliance that divides one larger hoseline into three or more small hoselines. Also called portable hydrant. (2) Top portion of the pump casing. (3) Used to join a number of discharge pipelines to a common outlet.
Man-made barriers Any barriers such as barricades, fallen trees, cables, trash bins, or vehicles blocking access to hydrants, sprinklers and standpipe connections, streets, or driveways.
Mansard Roof A roof characterized by steeply sloped facets surrounding a flat or nearly flat center section.
Manual Prying Tools Prying tools that use the principle of lever and fulcrum to provide mechanical advantage.
Master Stream Large-caliber water stream usually supplied by siamesing two or more hoselines into a manifold device or by fixed piping that delivers 350 gpm (1 400 l/min) or more. Also called heavy stream.
Material Safety Data Sheet (MSDS) Form provided by the manufacturer and blender of chemicals that contains information about chemical composition, physical and chemical properties, health and safety hazards, emergency response procedures, and waste disposal procedures of the specified material.
Matter Anything that occupies space and has mass.
Mechanical Heat Energy Heat that is generated by friction or compression. Moving parts on machines, such as belts and bearings, are a source of mechanical heating.
Mechanical Ventilation Any means other than natural ventilation. This type of ventilation may involve the use of fans, blowers, smoke ejectors, and fire streams.
Medium-Expansion Foam Foam concentrate that is mixed with air in the range of 20 parts air to 1 part foam solution (20:1) to 200 parts air to 1 part foam solution (200:1).
Medium-pressure Pneumatic Lifting Bags Considerably larger than high-pressure bags and are most commonly used to lift or stabilize large vehicles or objects.
Mine Safety and Health Administration (MSHA) United States government organization that regulates mine safety.
Miscibility Two or more liquids’ capability to mix together.
Mortar A mixture of sand, cement, and water used to bond masonry units into a solid mass. The joints between bricks are filled with mortar. Mortar joints are sometimes the easiest to penetrate when a masonry wall must be breached.
Mortise Notch, hole, or space cut into a door to receive a lock case, which contains the lock mechanism.
Mushrooming Tendency of heat, smoke, and other products of combustion to rise until they encounter a horizontal obstruction.Back to top
National Fire Incident Reporting System (NFIRS) One of the main sources of information (data, statistics) about fires in the United States.
National Fire Protection Association (NFPA) Nonprofit educational and technical association located in Quincy, Massachusetts devoted to protecting life and property from fire by developing fire protection standards and educating the public.
National Institute of Standards and Technology (NIST) A federal technology agency that develops and promotes measurement, standards, and technology.
Negative-Pressure Ventilation Technique using smoke ejectors to develop artificial circulation and to pull smoke out of a structure.
NIMS National Incident Management System
Nonintervention Strategy Strategy for handling fires involving hazardous materials where the fire is allowed to burn until all of the fuel is consumed.
Nonpiloted Ignition caused when a material reaches its autoignition temperature as the result of self-heating.
Nonthreaded Coupling Coupling with no distinct male or female components. Also called Storz Coupling or sexless coupling.
Nozzle Pressure Velocity pressure at which water is discharged from the nozzle.
Nuclear Heat Energy Creation of heat through the splitting apart or combining of atoms.Back to top
Occupational Safety and Health Administration (OSHA) U.S. federal agency that develops and enforces standards and regulations for occupational safety in the workplace.
ODP Abbreviation for Office for Domestic Preparedness.
Offensive Strategy Overall plan for incident control established by the Incident Commander (IC) in which responders take aggressive, direct action on the material, container, or process equipment involved in an incident.
Open Web Joist A joist constructed with a web composed of materials such as bars or tubes that do not fill the entire web space.
Open-Circuit Self-Contained Breathing Apparatus An SCBA that allows the wearer’s exhaled air to be discharged or vented to the atmosphere.
Operational Level Level of training established by the National Fire Protection Administration allowing first responders to take defensive actions at hazardous materials incidents.
Operations Section Chief Person responsible to the incident commander for managing all tactical operations directly applicable to accomplishing the incident objectives.
Order Specific rule, regulation, or authoritative direction.
Ordinary Construction--Type III Construction A type of construction in which exterior walls and structural members are noncombustible or limited combustible materials. Interior structural members, including walls, columns, beams, floors, and roofs, are completely or partially constructed of wood.
Oriented Strand Board (OSB) A wooden structural panel formed by gluing and compressing wood strands together under pressure.
OS&Y Valve Outside stem and yoke valve; a type of control valve for a sprinkler system in which the position of the center screw indicates whether the valve is open or closed.
OSHA Acronym for Occupational Safety and Health Administration, a division of the U.S. Department of Labor that develops and enforces standards and regulations for occupational safety in the workplace.
Out-of-Service Unit that is not available for assignment to a response.
Overcurrent Any current that is in excess of the rated current of equipment or the ampacity of a conductor, and may be caused by an overload, short circuit, or ground fault.
Overhand Safety Knot Knot used in conjunction with other knots to eliminate the danger of the running end of the rope slipping back through a knot, causing the knot to fail.
Overhaul Those operations conducted once the main body of fire has been extinguished that consist of searching for and extinguishing hidden or remaining fire, placing the building and its contents in a safe condition, determining the cause of the fire, and recognizing and preserving evidence of arson.
Oxidizer Any substance or material that yields oxygen readily and may stimulate the combustion of organic and inorganic matter. Also see Strong Oxidizer.
Oxyacetylene Cutting Torch A commonly used torch that burns oxygen and acetylene to produce a very hot flame. Used as a forcible entry cutting tool for penetrating metal enclosures that are resistant to more conventional forcible entry equipment.
Oxygasoline Cutting Torch A relatively new cutting system, fueled by gasoline and oxygen.
Oxygen (O2) A chemical element. Colorless, odorless, tasteless gas constituting 21 percent of the atmosphere.
Oxygen-Deficient Atmosphere Any atmosphere containing less than the normal 21 percent oxygen found in atmospheric air. At least 16 percent oxygen is needed for flame production and human life.
Oxyhemoglobin Combination of oxygen and hemoglobin.Back to top
Packaging (1) Broad term the U.S. Department of Transportation uses to describe shipping containers and their markings, labels, and/or placards. (2) Readying a patient for transport.
Padlock Detachable, portable lock with a hinged or sliding shackle.
Pancake Collapse Situation where the weakening or destruction of bearing walls cause the floors or the roof to collapse, which allows the debris to fall as far as the lower floor or basement.
Panel Door Door inset with panels, which are usually of wood, metal, glass, or plastic.
Parallel Chord Truss A truss constructed with the top and bottom chords parallel.
Paramedic Professional level of certification for emergency medical personnel who are trained in advanced life support procedures.
Parapet A wall at the edge of some roofs. Most parapet walls range from a few inches (millimeters) to a few feet (meters) in height, but can be high enough to require a ladder to reach the roof from the top of the wall.
Party Wall A wall shared by two adjoining buildings; usually a load-bearing wall that is also a fire wall.
Passive agents Materials that absorb heat but do not participate actively in the combustion reaction.
Pawls Devices attached to the inside of the beams on fly sections used to hold the fly section in place after it has been extended.
PC Abbreviation for Personal Computer.
PEL Acronym for Permissible Exposure Limit.
Perimeter The perimeter of a wildland fire is the boundary of the fire. It is the total length of the outer edge of the burning or burned area.
Permissible Exposure Limit (PEL) Maximum time-weighted concentration at which 95 percent of exposed, healthy adults suffer no adverse effects over a 40-hour workweek; an 8-hour time-weighted average unless otherwise noted; expressed in either parts per million (ppm) or milligrams per cubic meter (mg/m3).
Persistence Length of time a chemical agent remains effective without dispersing.
Personal Alert Device (PAD) Electronic lack-of-motion sensor that sounds a loud tone when a firefighter becomes motionless. It can also be manually triggered to operate.
Personal Alert Safety System (PASS) Electronic lack-of-motion sensor that sounds a loud tone when a firefighter becomes motionless. It can also be manually triggered to operate.
Personal Protective Equipment (PPE) General term for the equipment worn by firefighters and rescuers; includes helmets, coats, pants, boots, eye protection, gloves, protective hoods, self-contained breathing apparatus, and personal alert safety systems (PASS devices). Also called Bunker Clothes, Protective Clothing, Turnout Clothing, or Turnout Gear.
Personnel Accountability Report (PAR) A roll call of all units (crews, teams, groups, companies, sectors) assigned to an incident.
Photoelectric Smoke Detector Type of smoke detector that uses a small light source, either an incandescent bulb or a light-emitting diode (LED), to detect smoke by shining light through the detector’s chamber: smoke particles reflect the light into a light-sensitive device called a photocell.
Pick-Head Axe Forcible entry tool that has a chopping blade on one side of the head and a sharp pick on the other side.
Pike Pole Sharp prong and hook of steel, on a wood, metal, fiberglass, or plastic handle of varying length, used for pulling, dragging, and probing.
Piloted ignition Occurs when a mixture of fuel and oxygen encounter an external heat (ignition) source with sufficient heat energy to start the combustion reaction.
Piloted Ignition caused by a spark or flame.
Pin Lug Couplings Hose couplings with round lugs in the shape of a pin.
Pitch The ratio of rise to span of a roof assembly. The steeper the pitch, the greater the slip hazard unless roof ladders are used.
Pitched Roof A roof that it sloped (pitched) to facilitate runoff.
Pitot Tube Instrument that is inserted into a flowing fluid (such as a stream of water) to measure the velocity pressure of the stream; commonly used to measure flow.
Planning Section Chief (Plans) Responsible for the collection, documentation, evaluation, and dissemination of incident situation information and intelligence to the IC.
Plasma Cutters Ultra-high temperature metal-cutting devices that produce cutting temperatures as high as 25,000°F (13 871°C).
Plaster Hook Barbed collapsible hook on a pole used to puncture and pull down materials.
Plate The top or bottom horizontal member of a frame wall. The sole plate is nailed or screwed to the subfloor, and the top plate is what the roof assembly rests on.
Platform Construction Frame-type construction in which each floor interrupts the exterior studs forming an effective fire-stop at every floor.
Plywood A wooden structural panel formed by gluing and laminating very thin sheets of wood together under pressure.
Pneumatic Chisel/Hammer Pneumatic chisel is useful for extrication work; designed to operate at air pressures between 100 and 150 psi (700 kPa and 1 050 kPa).
Pneumatic Tools Tools that receive their operating energy from compressed air.
Pocket Doors Door that moves laterally into a "pocket" framed into the wall, usually suspended from an overhead track.
Point of Origin Exact physical location where the heat source and fuel come in contact with each other and a fire begins.
Poison Any material that when taken into the body is injurious to health. Also see Convulsant and Toxin.
Polar Solvents Flammable liquids that have an attraction for water, much like a positive magnetic pole attracts a negative pole; examples include alcohols, ketones, and lacquers.
Pole Ladder Large extension ladder that requires tormentor poles to steady the ladder as it is raised and lowered. Also called Bangor Ladder.
Policy A guide to decision making within an organization.
Pompier Ladder Scaling ladder with a single beam and a large curved metal hook that can be put over windowsills for climbing.
Portable Hydrant (1) Hose appliance that divides one larger hoseline into three or more small hoselines. Also called portable hydrant. (2) Top portion of the pump casing. (3) Used to join a number of discharge pipelines to a common outlet.
Porta-Power Manually operated hydraulic tool that has been adapted from the auto body business to the rescue service. This device has a variety of tool accessories that allows it to be used in numerous applications.
Positive-Pressure Ventilation (PPV) Method of ventilating a confined space by mechanically blowing fresh air into the space in sufficient volume to create a slight positive pressure within and thereby forcing the contaminated atmosphere out the exit opening.
Post Indicator Valve (PIV) A type of valve used to control underground water mains that provides a visual means for indicating "open" or "shut" position; found on the supply main of installed fire protection systems.
Potential Energy Stored energy possessed by an object that can be released in the future to perform work once released.
Power Saw A saw that is operated using a power source.
Powered Hydraulic Shears Large rescue tool whose two blades open and close by the use of hydraulic power supplied through a hose from a power unit.
Powered Hydraulic Spreaders Large rescue tool whose two arms open and close by the use of hydraulic power supplied through a hose from a power unit. This device is capable of exerting in excess of 20,000 pounds (900 kg) of force at its tips.
Preconnect (1) Attack hose connected to a discharge when the hose is loaded; this shortens the time it takes to deploy the hose for fire fighting. (2) Soft-sleeve intake hose that is carried connected to the pump intake. (3) Hard suction hose or discharge hose carried connected to a pump, eliminating delay when hose and nozzles must be connected and attached at a fire.
Pre-Incident Plan Document, developed during pre-incident planning, that contains the operational plan or set procedures for the safe and efficient handling of emergency situations at a given location (such as a specific building or occupancy).
Pre-Incident Planning Act of preparing to handle an incident at a particular location or a particular type of incident before an incident occurs.
Premixing Mixing pre-measured portions of water and foam concentrate in a container.
Preplan Document, developed during pre-incident planning, that contains the operational plan or set procedures for the safe and efficient handling of emergency situations at a given location (such as a specific building or occupancy).
Pressure Force per unit area exerted by a liquid or gas measured in pounds per square inch (psi) or kilopascals (kPa).
Primary Feeder Large pipes (mains), with relatively widespread spacing, that convey large quantities of water to various points of the system for local distribution to the smaller mains.
Private Branch Exchange (PBX) Telephone switching system found in large businesses or organizations that allows many users to be reached by dialing a seven-digit number. Internal users of a PBX system have special features available such as hold, conference calling, transfer, etc.
Procedure A written communication closely related to a policy.
Projected Window Type of swinging window that is hinged at the top and swings either outward or inward.
Proportioning The mixing of water with an appropriate amount of foam concentrate to form a foam solution.
Proprietary Alarm System Fire protection system owned and operated by the property owner.
Protected Premises Fire Alarm System (1) Alarm systems that alert and notify only occupants on the premises of the existence of a fire so that they can safely exit the building and call the fire department. If a response by a public safety agency (police or fire department) is required, an occupant hearing the alarm must notify the agency.
Protection Plates Plates fastened to a ladder to prevent wear at points where it comes in contact with mounting brackets.
Protective Action Distance Downwind distance from a hazardous materials incident within which protective actions should be implemented.
Protective Action Zone Area immediately adjacent to and downwind from the initial isolation zone, which is in imminent danger of being contaminated by airborne vapors within 30 minutes of material release.
Protective Actions Steps taken to preserve health and safety of emergency responders and the public.
Protective Clothing Includes the helmet, protective coat, protective trousers, protective hood, boots, gloves, self-contained breathing apparatus, and eye protection where applicable. See Personal Protective Equipment.
Protective Coat Coat worn during fire fighting, rescue, and extrication operations.
Protective Hood Hood designed to protect the firefighter’s ears, neck, and face from exposure to extreme heat.
Protective Trousers Pants worn during fire fighting operations. Also called turnout pants; bunker pants; night hitches.
Public Education Highly trained public education specialists who plan, organize, and in some cases deliver fire and life safety talks and demonstrations to local schools, businesses, and civic organizations.
Public Fire and Life Safety Educator Makes presentations and conducts seminars to inform the public about fire hazards, fire causes, precautions, and actions to take during a fire.
Public Information Officer Responsible for interfacing with the public and media and/or other agencies with incident-related information requirements.
Public Safety Answering Point (PSAP) Any location or facility at which 9-1-1 calls are answered either by direct calling, rerouting, or diversion.
Pulley (1) Small, grooved wheel through which the halyard is drawn on an extension ladder. (2) Wheel used to transmit power by means of a band, belt, cord, rope, or chain passing over its rim. (3) Steel or aluminum rollers used to change direction and to reduce friction in rope rescue systems.
Purlins Horizontal members that connect the steel, concrete, or laminated wood arches of trussless arched roofs.
Pyrolize Give off flammable vapor.
Pyrolysis (Pyrolysis Process or Sublimation) Thermal or chemical decomposition of fuel (matter) because of heat that generally results in the lowered ignition temperature of the material.Back to top
Quint Fire apparatus equipped with a fire pump, water tank, ground ladders, and hose bed in addition to the aerial device.Back to top
Radiation Transmission or transfer of heat energy from one body to another at a lower temperature through intervening space by electromagnetic waves such as infrared thermal waves, radio waves, or X rays.
Rafters Beams that span from a ridge board to an exterior wall plate to support roof decking.
Rails The two lengthwise members of a trussed ladder beam that are separated by truss or separation blocks.
Rain-Down Method This method of foam application directs the stream into the air above the unignited or ignited spill or fire and allows the foam to float gently down onto the surface of the fuel.
Rapid Intervention Crew (RIC) Two or more fully equipped and immediately available firefighters designated to stand by outside the hazard zone to enter and effect rescue of firefighters inside, if necessary.
Ratchet-Lever Jack Type of lifting jack that uses the principles of leverage to operate. It is capable of lifting moderately heavy loads but tends to be unstable.
Rate Compensated Heat Detector Temperature-sensitive device that sounds an alarm at a preset temperature, regardless of how fast temperatures change.
Rated Assembly Two or more construction components combined to form an assembly that has a specific fire resistance rating.
Rate-of-Rise Heat Detector Temperature-sensitive device that sounds alarm when the temperature changes at a preset value, such as 12°F to -15°F per minute.
Reactivity Ability of two or more chemicals to react and release energy and the ease with which this reaction takes place.
Rebar Short for reinforcing bar.
Rebar Cutters Cutting tool used for cutting rebar and security bars on windows or doors.
Rebreather Closed-circuit breathing apparatus.
Reciprocating Saw Electric saw that uses a short, straight blade that moves back and forth.
Recovery Situation where the victim is most probably dead, and the goal of the operation is to recover the body.
Reducer Adapter used to attach a smaller hose to a larger hose. The female end has the larger threads, while the male end has the smaller threads.
Rehab Abbreviation for Rehabilitation.
Rehabilitation (Rehab) Allowing emergency responders to rest, rehydrate, and recover during an incident; also refers to a station at an incident where personnel can rest, rehydrate, and recover.
Reinforced Concrete Concrete that has been poured into forms that contain an interconnected network of steel rebar.
Rekindle Reignition of a fire because of latent heat, sparks, or smoldering embers; can be prevented by proper overhaul.
Relative Humidity Measure of the moisture content (water quantity expressed in a percentage) in both the air and solid fuels.
Relay Operation Using two or more pumpers to move water over a long distance by operating them in series. Water discharged from one pumper flows through hoses to the inlet of the next pumper, and so on.
Relay Pumping Using two or more pumpers to move water over a long distance by operating them in series. Water discharged from one pumper flows through hoses to the inlet of the next pumper, and so on.
Repair To restore or put together that which has become inoperable or out of place.
Rescue Saving a life from fire or accident; removing a victim from an untenable or unhealthy atmosphere.
Rescue Company Specialized unit of people and equipment dedicated to performing rescue and extrication operations at the scene of an emergency.
Residual Pressure Pressure at the test hydrant while water is flowing. It represents the pressure remaining in the water supply system while the test water is flowing and is that part of the total pressure that is not used to overcome friction or gravity while forcing water through a fire hose, pipe, fittings, and adapters.
Resistance Heating Heat generated by passing an electrical current through a conductor such as a wire or an appliance.
Resource Status Unit (RESTAT) Functional unit within the planning section of an incident management system; responsible for recording and evaluating the status of resources committed to the incident, the impact that additional responding resources will have on the incident, and the anticipated resource needs.
Resources All of the immediate or supportive assistance available, or potentially available, for assignment to help control an incident including personnel, equipment, control agents, agencies, and printed emergency guides.
Reverse Lay Method of laying hose from the fire scene to the water supply.
Revolving Door Door made of three or four sections, or wings, arranged on a central pivot that operates by rotating within a cylindrical housing.
Rim Lock Type of auxiliary lock mounted on the surface of a door.
Riser (1) Vertical part of a stair step. (2) Vertical water pipe used to carry water for fire protection systems above ground such as a standpipe riser or sprinkler riser.
Roll-On Application Method (Bounce) Method of foam application in which the foam stream is directed at the ground at the front edge of the unignited or ignited liquid fuel spill; foam then spreads across the surface of the liquid.
Rollover Condition in which the unburned combustible gases release in a confined space (such as a room or aircraft cabin) during the incipient or early steady-state phase and accumulate at the ceiling level.
Roof Covering Final outside cover that is placed on top of a roof deck assembly.
Roof Ladder Straight ladder with folding hooks at the top end. The hooks anchor the ladder over the roof ridge.
Rope Hose Tool Piece of rope spliced to form a loop through the eye of a metal hook; used to secure hose to ladders or other objects.
Rotary Saw Fire service version of this device is usually gasoline powered and has changeable blades for cutting wood, metal, and masonry.
Round Turn Element of a knot that consists of further bending one side of a loop.
Rung Step portion of a ladder running from beam to beam.Back to top
Saddles Low area on a ridgeline between two higher points.
Safety Glass (Laminated Glass) Special glass composed of two sheets of glass that are laminated to a sheet of plastic sandwiched between them under high temperature and pressure.
Safety Goggles Enclosed, but adequately ventilated, goggles that have impact- and shatter-resistant lens to protect the eyes from dusts, chips, and other small particles; should be OSHA approved.
Safety Officer (1) Fire officer whose primary function is to administrate safety within the entire scope of fire department operations. Also referred to as the Health and Safety Officer. (2) Member of the IMS Command Staff responsible to the incident commander for monitoring and assessing hazardous and unsafe conditions and developing measures for assessing personnel safety on an incident. Also referred to as the Incident Safety Officer.
Safety Shoes (1) Rubber or neoprene foot plates, usually of the swivel type, attached to the butt end of the beams of a ground ladder. (2) Protective footwear meeting OSHA requirements.
Safety (1) Extra hitch tied in the end of a knot to prevent the end from being pulled through the knot. (2) Device designed to prevent an inadvertent or hazardous operation.
Salvage Methods and operating procedures associated with fire fighting by which firefighters attempt to save property and reduce further damage from water, smoke, heat, and exposure during or immediately after a fire by removing property from a fire area, by covering it, or other means.
Salvage Cover Waterproof cover made of cotton duck, plastic, or other material used by fire departments to protect unaffected furniture and building areas from heat, smoke, and water damage; a tarpaulin. Also called Tarp.
Saponification A phenomenon that occurs when mixtures of alkaline based chemicals and certain cooking oils come into contact resulting in the formation of a soapy film.
SAR Abbreviation for Supplied-Air Respirator.
Sawtooth Roof A roof with a profile of vertical and sloping surfaces that resemble a saw blade.
SCBA Abbreviation for Self-Contained Breathing Apparatus.
Search Techniques that allow the rescuer to identify the location of victims and to determine access to those victims in order to remove them to a safe area.
Search Warrant Written order, in the name of the People, State, Province, Territory, or Commonwealth, signed by a magistrate, commanding a peace officer to search for personal property or other evidence and return it to the magistrate.
Secondary Contamination Contamination of people, equipment, or the environment outside the hot zone without contacting the primary source of contamination; sometimes called cross contamination.
Secondary Feeder Network of intermediate -sized pipes that reinforce the grid within the loops of the primary feeder system and aid in providing the required fire flow at any given point in a sprinkler system.
Sector Either a geographic or function-based subdivision or assignment within the Fireground Command System or National Fire Service Incident Management System. A sector may take the place of either a Division or Group or both.
Seismic Effect Earth vibration created by an explosion that is similar to an earthquake.
Self-Closing Door Door equipped with a door closer.
Self-Contained Breathing Apparatus (SCBA) Respirator worn by the user that supplies a breathable atmosphere that is either carried in or generated by the apparatus and is independent of the ambient atmosphere.
Separating Act of creating a barrier between the fuel and the fire.
Service Branch Branch within the Logistics section of an Incident Management System; responsible for service activities at an incident.
Service Test Series of tests performed on apparatus and equipment in order to ensure operational readiness of the unit.
Sexless Coupling Coupling with no distinct male or female components. Also called Storz Coupling or sexless coupling.
Shank Portion of a coupling that serves as a point of attachment to the hose.
Sheathing Plywood, OSB, or wooden planking (sometimes called sheeting) applied to a wall or roof over which a weather resistant covering is applied.
Shed Roof Pitched roof with a single sloping aspect, resembling half of a gabled roof.
Shelter in Place Having occupants remain in a structure or vehicle in order to provide protection from a rapidly approaching hazard. Also see Evacuation.
Shoe Metal plate used at the bottom of heavy timber columns.
S-Hook Used for the same purpose as J-hooks. S-hook cannot be driven into walls or framing but must have a horizontal ledge (such as the top of a book case) from which to hang.
Shoring General term used for lengths of timber, screw jacks, hydraulic and pneumatic jacks, and other devices that can be used as temporary support for formwork or structural components or used to hold sheeting against trench walls. Individual supports are called shores, cross braces, and struts.
Short-Term Exposure Limit (STEL) Fifteen-minute time-weighted average that should not be exceeded at any time during a workday; exposures should not last longer than 15 minutes nor be repeated more than four times per day with at least 60 minutes between exposures.
Shove Knife Tool for moving a latch on a lock.
Siamese Appliances Hose appliance used to combine two or more hoselines into one. The siamese generally has female inlets and a male outlet and is commonly used to supply the hose leading to a ladder pipe.
Single Ladder One-section ladder.
Single Resource Individual company or crew.
Situation Status Unit (SITSTAT) Functional unit within the planning section of an Incident Management System; responsible for analysis of situation as it progresses; reports to planning section chief.
Skid load finish System of loading a fire hose so that the top layer can be pulled off at the fire.
Slab Door Door that has the appearance of being made of a single piece, or slab, of wood; may be of two types — either hollow core or solid core.
Sliding Door Door that opens and closes by sliding across its opening; usually on rollers.
Slopover (1) Fire edge that crosses a control line at a wildland fire. Also called Breakover. (2) Situation that occurs when burning oil that is stored in a tank is forced over the edge of the tank by water that is heated to the boiling point accumulates under the surface of the oil.
Small Diameter Hose (SDH) Hose of C|v to 2 inches (20 mm to 50 mm) in diameter; used for fire fighting purposes. Also called Small Line.
Small Line Hose of C|v to 2 inches (20 mm to 50 mm) in diameter; used for fire fighting purposes.
Smoke Detector Alarm-initiating device designed to actuate when visible or invisible products of combustion (other than fire gases) are present in the room or space where the detector is located.
Smoke explosion A form of fire gas ignition; the ignition of accumulated flammable products of combustion.
Smothering Act of excluding oxygen from a fuel.
Soft Sleeve Hose Large diameter, collapsible piece of hose used to connect a fire pump to a pressurized water supply source.
Solid Stream Hose stream that stays together as a solid mass as opposed to a fog or spray stream. A solid stream is produced by a smooth bore nozzle and should not be confused with a straight stream.
Solubility Degree to which a solid, liquid, or gas dissolves in a solvent (usually water).
SOP Abbreviation for Standard Operating Procedure.
Spalling Degradation of concrete due to prolonged exposure to high heat. Water trapped within the concrete is vaporized by the heat and expands causing the concrete to break apart.
Span of Control Maximum number of subordinates that that one individual can effectively supervise. This number ranges from three to seven individuals or functions, with five generally established as optimum.
Spanner Wrench Small tool primarily used to tighten or loosen hose couplings; can also be used as a prying tool or a gas key.
Spark Small bit of solid material heated to incandescence.
Special Fire Hazard Fire hazard arising from the processes or operations that are peculiar to the individual occupancy.
Special Rescue Company Responds to and performs technical rescues.
Specific Gravity Weight of a substance compared to the weight of an equal volume of water at a given temperature. A specific gravity less than1 indicates a substance lighter than water; a specific gravity greater than 1 indicates a substance heavier than water.
Split Lay Hose lay deployed by two pumpers, one making a forward lay and one making a reverse lay from the same point.
Spontaneous Heating Heating resulting from chemical or bacterial action in combustible materials that may lead to spontaneous ignition. Also known as Self-heating.
Spot Fire Natural cover fires started outside the perimeter of a main fire; typically caused by flying sparks or embers landing outside the main fire area.
Sprinkler Waterflow device in a sprinkler system. The sprinkler consists of a threaded nipple that connects to the water pipe, a discharge orifice, a heat-actuated plug that drops out when a certain temperature is reached, and a deflector that creates a stream pattern that is suitable for fire control.
Sprinkler System A fixed piping system that is designed to discharge water in the event of a fire.
Stack Effect Tendency of any vertical shaft within a tall building to act as a chimney or "smokestack" by channeling heat, smoke, and other products of combustion upward due to convection. Also called Chimney Effect.
Standard Operating Procedures (SOPs) Standard methods or rules in which an organization or a fire department operates to carry out a routine function.
Standing Part That part of a rope between the working end and the running part.
Static (1) Stationary; without movement. (2) Refers to the amount of stretch built into a rope.
Static Pressure (1) Potential energy that is available to force water through pipes and fittings, fire hose, and adapters. (2) Pressure at a given point in a water system when no water is flowing.
Stops Wood or metal pieces that prevent the fly section of a ladder from being extended too far.
Straight Ladder One-section ladder.
Straight Lay Hose laid from the hydrant or water source to the fire.
Straight Stream The most compact discharge pattern that a fog nozzle can produce; similar to but not as compact as a solid stream.
Strategic Goals Broad statements of desired achievement to control an incident; achieved by the completion of tactical objectives.
Strategic Mode Determines the positions for companies operating on scene.
Strategy Overall plan for incident attack and control established by the Incident Commander (IC).
Stratification Formation of smoke into layers as a result of differences in density with respect to height with low density layers on the top and high density layers on the bottom.
Strike Team Specified combinations of the same kind and type of resources with common communications and a leader. Strike teams are most often composed of either engines, hand crews, or bulldozers, but they may be composed of any resource of the same kind and type.
Strip Ventilation Defensive tactic that involves cutting an exit opening in the roof of a burning building, extending from one outside wall to the other, to create an opening at which a spreading fire may be cut off. Also called Strip Vent.
Stud A vertical structural member in a frame wall.
Subsurface Fuel All combustible materials below the surface litter, such as tree or shrub roots, peat, and sawdust, that normally support smoldering combustion without flame.
Supervisor (1) A person who is responsible for directing the performance of other people or employees. (2) IMS term for the individual responsible for command of a Division, Group, or Sector.
Supplied Air Respirator An atmosphere-supplying respirator for which the source of breathing air is not designed to be carried by the user; not certified for fire fighting operations.
Support Branch Branch within the logistics section of an incident management system; responsible for providing the personnel, equipment, and supplies to support incident operations.
Suppressing The act of preventing the release of flammable vapors and therefore reducing the possibility of ignition or reignition. Also known as smothering.
Surface Fuel Fuel that contacts the surface of the ground; consists of duff, leaf and needle litter, dead branch material, downed logs, bark, tree cones, and low-stature living plants.
Surface-To-Mass Ratio The ratio of the surface area of the fuel to the mass of the fuel.
Survey Evaluation instrument used to identify the behavior and/or attitude of an individual or audience both before and after a presentation.
Swivel Gasket Free-turning ring on all Storz fire hose couplings and on the female coupling of threaded couplings.
Systemic Effect Something that affects an entire system rather than a single location or entity.Back to top
Tackle The assembly of ropes used to multiply the pulling force.
Tactical Objectives Specific operations that must be accomplished to achieve strategic goals.
Tactics Methods of employing equipment and personnel on an incident to accomplish specific tactical objectives in order to achieve established strategic goals.
Tag Line (1) Nonload-bearing rope attached to an object to help steer it in a desired direction or act as a safety line. (2) As used in anchors, length of rope or webbing used to extend anchor points closer to the actual rescue work site.
Target Hazard Facility in which there is a great potential likelihood of life or property loss.
Tarp Waterproof cover made of cotton duck, plastic, or other material used by fire departments to protect unaffected furniture and building areas from heat, smoke, and water damage; a tarpaulin.
Task Force (1) Group of individuals convened to analyze, investigate, or solve a particular problem. (2) Group of resources with common communications and a leader temporarily assembled for a specific mission. (3) Any combination of single resources, within a reasonable span of control, assembled for a particular tactical need with common communications and a leader.
Technical Rescuer Handles technical rescue situations such as high-angle (rope) rescue, trench and structural collapse, confined space entry, extrication operations, and cave or mine rescues.
Telecommunications Device For The Deaf (TDD) Special type of phone used by hearing-impaired individuals that sends text messages.
Teletype (TTY) Similar to a TDD device in which messages are sent over phone lines.
Temperature Measurement of the intensity of the heating of a material.
Tempered Glass Type of glass specially treated to become harder and more break-resistant than plate glass or a single sheet of laminated glass.
Tension Those vertical or horizontal forces that tend to pull things apart; for example, the force exerted on the bottom chord of a truss.
Tepee Cut Triangular opening cut in a roll-up or tilt-slab door to provide access into the building or a means of egress for those inside.
Thermal Layering (of Gases) Outcome of combustion in a confined space in which gases tend to form into layers, according to temperature, with the hottest gases are found at the ceiling and the coolest gases at floor level.
Thermal windows Windows with multiple panes
Thermoelectric-Effect Heat Detector Heat-sensitive device that measures electrical resistance changes that correspond with temperature changes.
Threaded Coupling Male or female coupling with a spiral thread.
Threshold Limit Value (TLV®) Concentration of a given material in parts per million (ppm) that may be tolerated for an 8-hour exposure during a regular workweek without ill effects.
TIC Abbreviation for Toxic Industrial Chemical.
Tie Rods Metal rods running from one beam to the other.
Tip (1) Extreme top of a ladder. Also called Top. (2) Slang for a nozzle.
Topography Physical configuration of the land or terrain.
Toxic Atmosphere Any area, inside or outside a structure, where the air is contaminated by a poisonous substance that may be harmful to human life or health if it is inhaled, swallowed, or absorbed through the skin.
Toxic Material Substance classified as a poison, asphyxiant, irritant, or anesthetic that can be poisonous if inhaled, swallowed, absorbed, or introduced into the body through cuts or breaks in the skin.
Toxin Substance that has the property of being poisonous.
Trailer Combustible material, such as rolled rags, blankets, newspapers, or flammable liquid, often used in intentionally set fires to connect remote fuel packages (combustible materials, pools of ignitable liquid, etc.) in order to spread fire from one point or area to other points or areas. Frequently used in conjunction with an incendiary device.
Training Officer/Chief of Training/Drillmaster Administers all fire department training activities.
Training Supervised activity or process for achieving and maintaining proficiency through instruction and hands-on practice in the operation of equipment and systems that are expected to be used in the performance of assigned duties. Also called Drilling.
Trench Jack Any jack used to keep sheeting or wales apart for the insertion of a breast timber in a trenching operation.
Trench Ventilation Defensive tactic that involves cutting an exit opening in the roof of a burning building, extending from one outside wall to the other, to create an opening at which a spreading fire may be cut off. Also called Strip Vent.
Triage System used for sorting and classifying accident casualties to determine the priority for medical treatment and transportation.
Triangular Cut Triangular opening cut in a roll-up or tilt-slab door to provide access into the building or a means of egress for those inside. Also called Tepee Cut.
Tripods Rescue tripods are used to create an anchor point above a manhole or other opening.
Truck Company (Ladder Company) Group of firefighters assigned to a fire department aerial apparatus who are primarily responsible for search and rescue, ventilation, salvage and overhaul, forcible entry, and other fireground support functions.
Truss A wooden or metal structural unit made up of one or more triangles in a flat plane.
Truss Block Used to separate the beams of a truss beam ladder. Also called Beam Block and Run Block.
Turnout Gear Term used to describe personal protective clothing made of fire resistant materials that includes coats, pants, and boots. Also referred to as Turnout Clothing, Turnout Boots, Turnout Coat, Turnout Pants, Turnouts, or Bunker Gear.
Two-Way Radio Voice network that provides an always-on connection that enables the user to just "push the button and talk."
Tying In (1) Securing oneself to a ladder; accomplished by using a rope hose tool or belt or by inserting one leg between the rungs. (2) Securing a ladder to a building or object.
Type II Construction Similar to Type I except that the degree of fire resistance is lower.\ Back to top
Under Control Term used to describe the point in a fire incident when the fire’s progress has been stopped. Final extinguishment and overhaul can begin at this time.
Underwriters Laboratories, Inc. (UL) " Independent fire research and testing laboratory with headquarters in Northbrook, Illinois that certifies equipment and materials.
United States Department of Transportation (DOT) Federal agency that regulates the transportation of hazardous materials. Formerly known as Interstate Commerce Commission.
Unity of Command Organizational principle in which workers report to only one supervisor in order to eliminate conflicting orders and the confusion that would result.
Upper Flammable Limit (UFL) Upper limit at which a flammable gas or vapor will ignite. Above this limit the gas of vapor is too rich to burn (lacks the proper quantity of oxygen).
USFA Abbreviation for the United States Fire Administration.
Utility Rope Rope to be used in any situation that requires a rope — except life safety applications - including hoisting equipment, securing unstable objects, and cordoning off an area.Back to top
Vapor Density Weight of a given volume of pure vapor or gas compared to the weight of an equal volume of dry air at the same temperature and pressure. A vapor density less than 1 indicates a vapor lighter than air; a vapor density greater than 1 indicates a vapor density heavier than air.
Vaporization Process of evolution that changes a liquid into a gaseous state.
Ventilation Systematic removal of heated air, smoke, gases or other airborne contaminants from a structure and replacing them with cooler and/or fresher air to reduce damage and to facilitate fire fighting operations.
Vertical Ventilation Ventilating at the highest point of a building through existing or created openings and channeling the contaminated atmosphere vertically within the structure and out the top.
Violation Infringement of existing rules, codes, or laws.
Volatility Ability of a substance to vaporize easily at a relatively low temperature.
Volunteer Anyone, inside or outside the fire department, who helps with fire and life safety education programs.
V-Type Collapse Situation where the excess weight of heavy loads, such as furniture and equipment, concentrated near the center of the floor causes the floor to give way. A V-type collapse will result in void spaces near the walls.Back to top
Water Hammer Force created by the rapid deceleration of water causing a violent increase in pressure that can be powerful enough to rupture piping or damage fixtures.
Water Shuttle Operation Method of water supply by which tenders/tankers continuously transport water between a fill site and the dump site located near the emergency scene.
Water Supply Any source of water available for use in fire fighting operations.
Water Thief Any of a variety of hose appliances with one female inlet inlet for 2½ inch (65 mm) or larger hose and with three gated outlets, usually two 1½ inch (38 mm) outlets and one 2½ inch (65 mm) outlet.
Water Tower Aerial device primarily intended for deploying an elevated master stream.
Water Vacuum Appliance similar to a household vacuum cleaner designed to pick up water.
Webbing Synthetic nylon, spiral weave, tubular material used for creating anchors, lashings, and for packaging patients and rescuers.
Wet-Barrel Hydrant Fire hydrant that has water all the way up to the discharge outlets.
Whizzer Saw An air-driven cutting device with several advantages over other types of power saws.
Wildland Firefighter I (NFPA) Person, at the first level of progression, who has demonstrated the knowledge and skills necessary to function safely as a member of a wildland fire-suppression crew. The Wildland Firefighter I works under direct supervision.
Wildland Firefighter II (NFPA) Person, at the second level of progression, who has demonstrated the skills and depth of knowledge necessary to function under general supervision. This person shall function safely and effectively as a member of a wildland fire-suppression crew of equally or less experienced firefighters to accomplish a series of tasks. The Wildland Firefighter II can be called upon to provide leadership and temporary supervision of a small crew. The Wildland Firefighter II maintains direct communications with a supervisor.
Wildland Firefighter III (NFPA) Person responsible for supervising and directing a single wildland fire-suppression resource such as a hand crew or an engine.
Wildland Firefighter IV (NFPA) Person responsible for managing all aspects of a wildland fire incident, involving relatively few resources. Resources vary from a single firefighter to several single resources of different types or kinds.
Wildland Firefighter Responds to and mitigates fires in outdoor vegetation including the wildland/urban interface.
Winch Pulling tool that consists of a length of steel chain or cable wrapped around a motor-driven drum. These are most commonly attached to the front or rear of a vehicle.
Wind Horizontal movement of air relative to the surface of the earth.
Windward Side (1) The unprotected side of the building the wind is striking. (2) The side or direction from which the wind is blowing.
Wood-Frame Construction--Type V Construction A type of construction that has exterior walls, bearing walls, floors, roofs, and supports that are made completely or partially of wood or other approved materials of smaller dimensions than those used for Type IV construction.
Working End Part of the rope that is to be used in forming the knot. Also called Loose End.
Wye Hose appliance with one female inlet and two or more male outlets, usually smaller than the inlet. Outlets are also usually gated.Back to top