Purpose: To provide definitions to commonly used terms used in the firefighting profession. While all terms may not be used within Three Star Fire Department, it is imperative that all Officers and firefighters become familiar with terms for use within the Incident Command System. Common Terminology insures that all personnel are able to communicate effectively across departments and jurisdictions. The more simple the message, the more effective communications will be.
Above-ground storage tank: Storage tank that is not buried. Unburied tanks are more prone to physical damage, and leaks are released to the air or ground, rather than the soil surrounding a buried tank.
Accountability: The process of emergency responders (fire, police, SAR, emergency medical, etc...) checking into and making themselves announced as being on-scene during an incident to an incident commander or accountability officer. Through the accountability system, each person is tracked throughout the incident until released from the scene by the incident commander or accountability officer. This is becoming a standard in the emergency services arena primarily for the safety of emergency personnel. This system may implement a name tag system or personal locator device.
Apparatus: A term used to describe a piece of equipment, usually a company vehicle.
Autoextended fire: structure fire that has gone out a window or other opening on one floor and ignited materials above, on another floor or other space (attic, cockloft).
Available flow: total amount of water that can be put on a fire, depending upon water supply, pump size, hoses, and distance to the fire. IC must assess available flow to determine whether additional apparatus or streams are required.
Backdraft: A fire phenomenon caused when heat and heavy smoke (unburned fuel particles) accumulate inside a compartment, depleting the available air, and then oxygen/air is re-introduced, completing the fire triangle and causing rapid combustion.
Cockloft: structural space above ceiling and below rafters, often connecting adjacent occupancies and permitting fire to spread laterally, often unseen.
Collapse zone: The area around a structure that would contain debris if the building were to collapse.
Company: two or more firefighters organized as a team, led by a fire officer, and equipped to perform certain operational functions. Compare with platoon and unit.
Compartment Fire: An "Isolated" fire, or a fire which is "boxed in" or "closed off" from the rest of the structure. An example of this is a fire in a room where all the windows and doors are closed preventing the fire from spreading to other rooms.
Cross lay: Arrangement of hose on a pumper such that it can be quickly unloaded from either side of the apparatus; often pre-connected to a pump outlet and equipped with a suitable nozzle.
Direct attack: "Putting the wet stuff on the red stuff." A form of fire attack in which hoses are advanced to the fire inside a structure and hose streams directed at the burning materials.
Discharge flow: The amount of water flowing from a fire hydrant when it is opened; compare to static flow and residual flow.
Dispatch: Refers to person or place designated for handling a call for help by alerting the specific resources necessary.
Draft: The process of pumping water from a static source below the pump.
Drills: training during which an emergency is simulated and the trainees go through the steps of responding as if it were a real emergency.
Electrical fire: A fire in which the primary source of heat is electricity, resulting in combustion of adjacent insulation and other materials; may be hazardous to attempt to extinguish using water.
EMS: Emergency medical service(s).
Engine: A fire suppression vehicle that has a water pump and, typically, is designed to carry firehose and a limited supply of water.
Engine Company: A group of firefighters assigned to an apparatus with a water pump and equipped with firehose and other tools related to fire extinguishment.
Evacuation: Removal of personnel from a dangerous area, in particular, a HAZMAT incident, burning building, or other emergency. Also refers to act of removing firefighters from a structure in danger of collapsing.
Evolution: Uniform sequence of practiced steps by squad carrying out common tasks such as selection and placement of ladders, stowing hoses in hose bed, putting hoses and tools into service in particular patterns; intended to result in predictability during emergencies.
Exposure: Property near fire that may become involved by transfer of heat or burning material from main fire, typically by convection or radiation. May range from 40 feet to several miles, depending on size and type of fire or explosion.
Extrication: removal of a trapped victim such as a vehicle extrication, confined space rescue, or trench rescue; sometimes using hydraulic spreader, Jaws of Life, or other technical equipment.
FAST (or F.A.S.T.): Firefighter Assist and Search Team (also called Rapid Entry Team or Rapid Intervention Team) — firefighters assigned to stand by for rescue of other firefighters inside a structure; an implementation to support the Two-in, two-out rule; may have specialized training, experience and tools.
Firefighter: People who respond to fire alarms and other emergencies for fire suppression, rescue, and related duties.
Fire flow: The amount of water being pumped onto a fire, or required to extinguish a hypothetical fire. A critical calculation in light of the axiom that an ordinary fire will not be extinguished unless there is sufficient water to remove the heat of the fire.
Fireground: The operational area at the scene of a fire; area in which incident commander is in control. Also used as name of radio frequency to be used by units operating in the fireground, as in “Responding units switch to fireground.”
Fire hazard: Materials, structures or processes that may result in creating a fire, permitting a fire to grow undetected, or preventing people from escaping a fire.
Fire line: A boundary of a fire scene established for public safety and to identify the area in which firefighters may be working.
Fire marshal: Administrative and investigative office for fire prevention and arson investigation.
Fire prevention: Fire safety; standards for minimizing fire hazards.
Fire-resistant: Materials designed or treated to have an increased fire point.
Fire tetrahedron: The fire tetrahedron is based on the components of igniting or extinguishing a fire. Each component represents a property necessary to sustain fire: fuel, oxygen, heat, and chemical chain reaction. Extinguishment is based upon removing or hindering any one of these properties.
Fire triangle: Model for understanding the major components necessary for fire: heat, fuel and oxygen. See also fire tetrahedron for a more comprehensive model.
Fire wall: Building structure designed to delay horizontal spread of a fire from one area of a building to another; often regulated by fire code and required to have self-closing doors, and fireproof construction.
Fire watch: Fixed or mobile patrols that watch for signs of fire or fire hazards so that any necessary alarm can be quickly raised or preventive steps taken.
Fit test: Periodic test of how well the facepiece of an SCBA fits a particular firefighter.
Flash point: Lowest temperature at which a material will emit vapor combustible in air mixture. Lower than fire point of same material.
Flashover: simultaneous ignition of combustible materials in a closed space, as when materials simultaneously reach their fire point; may also result in rollover.
Forcible entry: gaining entry to an area using force to disable or bypass security devices, typically using force tools, sometimes using tools specialized for entry (e.g., Halligan, K-tool).
Forward lay: Procedure of stringing water supply hose from a water source toward a fire scene; compare with reverse lay.
Freelancing: dangerous situation at an incident where an individual carries out tasks alone or without being assigned; violation of personnel accountability procedures.
Friction loss: Reduction of flow in a firehose caused by friction between the water and the lining of the hose. Depends primarily upon diameter, type and length of hose, and amount of water (GPM) flowing through.
Fully involved: Term of size-up meaning fire, heat and smoke in a structure are so widespread that internal access must wait until fire streams can be applied.
GPM: Gallons Per Minute or how many gallons are being pumped out of a piece of equipment every minute
Grease fire: A fire involving any manner of cooking oil or other flammable cooking or lubricating materials.
Hazard: a source of danger of personal injury or property damage; fire hazard refers to conditions that may result in fire or explosion, or may increase spread of an accidental fire, or prevent escape from fire. Under worker safety and health regulations, employers have a general duty to provide a workplace free of hazards. See also fire prevention, and HAZMAT.
HAZMAT: Hazardous materials, including solids, liquids, or gasses that may cause injury, death, or damage if released or triggered.
High-pressure system: A supplemental pump system used to pressurize the water supply, sometimes used during a large fire, or whenever more than one hydrant is being used.
High-rise building: Any building taller than three or four stories, depending upon local usage, requiring firefighters to climb stairs or aerial ladders for access to upper floors.
Hot zone: contaminated area of HAZMAT incident that must be isolated; requires suitable protective equipment to enter and decontamination upon exit; minimum hot zone distance from unknown material with unknown release is 330 feet (United Nations Emergency Response Guidebook); surrounded by "warm zone" where decontamination takes place.
IDLH: Any situation deemed Immediately Dangerous to Life and Health. More narrowly defined by OSHA. See main IDLH article. An area of maximum danger to firefighters.
Incident Commander: The officer in charge of all activities at an incident.
Incident Safety Officer: The officer in charge of scene safety at an incident.
Indirect attack: Method of firefighting in which water is pumped onto materials above or near the fire so that the splash rains onto the fire, often used where a structure is unsafe to enter.
Initial attack: First point of attack on a fire where hose lines or fuel separation are used to prevent further extension of the fire.
Interface zone (also wildland/structural interface or urban/wildland interface): The zone where wildfires threaten structures or structural fires threaten wildlands, such as in residential areas adjacent to forests. This requires both wildland firefighting and structural firefighting in the same location, which involve very different tactics and equipment.
ISO Rating: (Insurance Services Office Fire Insurance Rating) This is a rating published by the Insurance Services Office. Insurance companies use this number to determine homeowner insurance premiums.
Live line: A fire hose under pressure from a pump. Also, an energized electrical line that may cause a hazard to firefighters.
Mass casualty incident (MCI): Any incident that produces a large number of injured persons requiring emergency medical treatment and transportation to a medical facility. The exact number of patients that makes an incident "mass casualty" is defined by departmental procedures and may vary from area to area.
Master stream: A large nozzle, either portable or fixed to a pumper, capable of throwing large amounts of water relatively long distances.
Means of egress: The way out of a building during an emergency; may be by door, window, hallway, or exterior fire escape; local fire codes will often dictate the size. location and type according to the number of occupants and the type of occupancy.
Multiple alarms: A request by an incident commander for additional personnel and apparatus. Each department will vary on the number of apparatus and personnel on each additional alarm.
Mutual aid: An agreement between nearby fire companies to assist each other during emergencies by responding with available manpower and apparatus.
NFPA: The National Fire Protection Association, a research group which sets a number of standards and best practices for *firefighting, equipment, and fire protection in the United States.
NIOSH: National Institute for Occupational Safety and Health. A U.S. agency responsible for investigation of workplace deaths, including firefighters.
Nozzle pressure: Pressure in a fire hose measured at the nozzle.
Nozzle reach: The distance a fire stream will travel from the nozzle tip before breaking up or evaporating due to air friction or heat.
Occupancy: Zoning and safety code term used to determine how a structure is permitted to be used and occupied, which in turn dictates the necessary safety structures and procedures.
Offensive attack: Method of firefighting in which water or other extinguisher is taken directly to the seat of the fire, as opposed to being pumped in that general direction from a safe distance.
OSHA: U.S. government agency concerned with regulating employee safety, particularly in hazardous occupations such as firefighting.
Outside fire: Urban fire not inside a building or vehicle, often found to be burning trash which could extend to nearby structures or vehicles if not dealt with properly. A suburban, interface, or rural outside fire could also be a wildland fire.
Overhauling: Late stage in fire-suppression process during which the burned area is carefully examined for remaining sources of heat that may re-kindle the fire. Often coincides with salvage operations to prevent further loss to structure or its contents, as well as fire-cause determination and preservation of evidence.
Oxidizer: A hazardous material containing oxygen that can combine with adjacent fuel to start or feed a fire.
Personnel accountability system: Tag, 'passport', or other system for identification and tracking of personnel at an incident, especially those entering and leaving an IDLH area; intended to permit rapid determination of who may be at risk or lost during sudden changes at the scene.
Positive pressure: Pressure at higher than atmospheric; used in SCBA facepieces and in smoke-proof stairwells to reduce entry of smoke or fumes through small openings.
Pre-fire, pre-incident planning: Information collected by fire prevention officers to assist in identifying hazards and the equipment, supplies, personnel, skills, and procedures needed to deal with a potential incident.
Pre-planning: Fire protection strategy involving visits to potentially hazardous occupancies for inspection, follow-up analysis and recommendations for actions to be taken in case of specific incidents.
"Probie:" (also rookie) new firefighter on employment probation (a period of time during which his or her skills are improved, honed, tested, and evaluated).
Public alarm: Means for public to report a fire, includes telephone, street-corner pull-boxes, building pull-stations, and manual bells or sirens in rural areas.
Pump operator, technician: (also a chauffeur): person responsible for operating the pumps on a pumper and typically for driving the pumper to an incident.
Pumper company: Squad or company that mans a fire engine (pumper) and carries out duties involving getting water to the fire.
Radiant extension: fire that has transferred ignition heat to adjacent materials across open space. One reason some city fire codes prohibit windows facing each other in adjacent warehouses.
Rapid intervention team: firefighters assigned to stand by for rescue of other firefighters inside a structure; an implementation to support the Two-in, two-out rule; may have specialized training, experience and tools.
Recovery: Location and removal of deceased victims. Also, the time needed for a firefighter to spend in rehab before being considered ready to continue working the incident.
Reflash, re-kindle: A situation in which a fire, thought to be extinguished, resumes burning.
Reflash Watch: A person assigned to observe and monitor an extinguished fire, to ensure that it does not reflash or re-kindle.
Rehab, Rehabilitation sector: An area for physical and mental recuperation at a fire scene, usually equipped with beverages, and chairs, isolated from environmental extremes (cold, heat, noise, smoke). This rest area enables firefighters to relax, cool off (or warm up) and regain hydration by way of preventing injury. An EMT may be assigned to monitor firefighter vitals when they enter and leave rehab.
Rescue: Physical removal of a live person or animal from danger to a place of comfort.
Rescue company: Squad of firefighters trained and equipped to enter adverse conditions and rescue victims of an incident. Often delegated to a truck company.
Residential sprinkler system: A sprinkler system arranged for fire suppression in a dwelling.
Residual pressure: The amount of pressure in a hydrant system when a hydrant is fully open, such as during a fire; should be engineered to provide domestic supply of water to homes and businesses during a large fire in the district.
Reverse lay: The process of stringing hose from a fire toward a source of water, i.e., a fire hydrant.
Salvage, salvage cover: Heavy-duty tarpaulins folded or rolled for quick deployment to cover personal property subjected to possible water or other damage during firefighting.
Scene safety: Steps taken at or near an emergency scene to reduce hazards and prevent further injuries to workers, victims or bystanders.
Search and rescue (or SAR): Entering a fire building or collapse zone for an orderly search for victims and removal of live victims. Becomes "recovery" if victims are not likely to be found alive.
Sector: A physical or operational division of an incident; an area supervised as a branch in the Incident Command System. A typical system for structure fires names the "front" of the building "sector A", and continues clockwise around the building (B, C, D), with interior sectors denoted by the floor number (1, 2, 3, etc.). A "rehab" sector is one example of an operational division at an incident, where personnel are assigned after strenuous work in another sector.
Shoulder load: The amount of hose a single firefighter can pull off a hose wagon or pumper truck and carry toward the fire.
Sides A, B, C, and D: Terms used by firefighters labeling the multiple sides of a building starting with side A or Alpha being the front of the structure and working its way around the outside of the structure in a clockwise direction. This labels the front side A or Alpha, the left side B or Bravo, the rear side C or Charlie, and the right side D or Delta.
Size-up: initial evaluation of an incident, in particular a determination of immediate hazards to responders, other lives and property, and what additional resources may be needed. Example: "Two-story brick taxpayer with heavy smoke showing from rear wooden porches and children reported trapped."
Solid stream: fire stream from round orifice of nozzle. Compare straight stream.
Staging: sector of incident command where responding resources arrive for assignment to another sector. Often an essential element in personnel accountability program.
Standard operating procedure, guideline (SOP or SOG): Rules for the operation of a fire department, such as how to respond to various types of emergencies, training requirements, use of protective equipment, radio procedures; often include local interpretations of regulations and standards. In general, "procedures" are specific, whereas "guidelines" are less detailed.
Static pressure: The pressure in a water system when the water is not flowing.
Straight stream: Round, hollow stream formed as water passes a round baffle through a round orifice (e.g., on an adjustable nozzle.)
Stretch: command to lay out (and connect) firehose and nozzle.
Structure fire (or "structural fire"): A fire in a residential or commercial building. Urban fire departments are primarily geared toward structural firefighting. The term is often used to distinguish them from wildland fire or other outside fire, and may also refer to the type of training and equipment (e.g., "structure PPE").
Tailboard: Portion at rear of fire engine where firefighters could stand and ride (now considered overly dangerous), or step up to access hoses in the hose bed.
Truck company: a group of firefighters assigned to an apparatus that carries ladders, forcible entry tools, possibly extrication tools and salvage covers, and who are otherwise equipped to perform rescue, ventilation, overhaul and other specific functions at fires; also called "ladder company".
Turnout Gear: The protective clothing worn by firefighters
Two-in, two-out (or "two in/two out": Refers to the standard safety tactic of having one team of two firefighters enter a hazardous zone (IDLH), while at least two others stand by outside in case the first two need rescue — thus requiring a minimum of four firefighters on scene prior to starting interior attack. Also refers to the "buddy system" in which firefighters never enter or leave a burning structure alone.
Type I, II, III, IV, V Building - U.S. classification system for fire resistance of building construction types, including definitions for "resistive" Type I, "non-combustible" Type II, "ordinary" Type III, heavy timber Type IV, and "frame construction" Type V (i.e., made entirely of wood).
T-Boner A car crash situation, where one car has hit the side of another which is traveling at an angle horizontal to the car which has struck the other car, generally these crashes are quite severe and much fuel is spilled.
Universal precautions: The use of safety barriers (gloves, mask, and goggles) to limit an emergency responder's contact with contaminants, especially fluids of injured patients.
Vehicle fire: Type of fire involving motor vehicles themselves, their fuel or cargo; has peculiar issues of rescue, explosion sources, toxic smoke and runoff, and scene safety.
Ventilation: Important procedure in firefighting in which the hot smoke and gases are removed from inside a structure, either by natural convection or forced, and either through existing openings or new ones provided by firefighters at appropriate locations (e.g., on the roof). Proper ventilation can save lives and improper ventilation can cause backdraft or other hazards.
Venturi effect: Creating a partial vacuum using a constricted fluid flow, used in fire equipment for mixing chemicals into water streams, or for measuring flow velocity.
Vertical ventilation: Ventilation technique making use of the principle of convection in which heated gases naturally rise.
Voids (building): Enclosed portions of a building where fire can spread undetected.
Vollie: A volunteer firefighter.
Volunteer fire department: A group of part-time firefighters who are not paid when on-call, during incidents, or drills. Often professionally trained and equipped with state-of-the-art equipment.
Water hammer: Large, damaging shock wave in a water supply system caused by shutting a valve quickly or by permitting a vehicle to drive across an unprotected fire hose.
Wildfire or Wildland fire: Fire in forests, grasslands, prairies, or other natural areas, not involving structure fires (although wildland fires may threaten structures or vice versa - see interface zone.) For a complete list of terms used in wildland fire, see Glossary of wildland fire terms.
Working fire: A fire that is in the process of being suppressed; often a cue for dispatch of additional resources.
Wye: Device used to split a larger supply line hose into smaller attack line hoses. A gated wye contains valves so that certain lines can be turned on and off.
Yield: What other drivers are supposed to do when they see or hear emergency vehicles approaching with lights and/or sirens activated.
Zone: Section of structure indicated on fire alarm control panel where sensor was activated.