Glossary of firefighting

A

• 3D zone control: The strategy of 3D zone control intended to improve the safety of firefighters operating inside a burning structure. It attempts to safeguard the immediate locality of any space occupied by firefighters in resorting to various defensive actions that confine the fire; remove combustion products safely and effectively; or mitigate dangers in the hot-gas layers. The overall tactical objective is to provide more permanent levels of protection in structural compartments, from which firefighters may operate in various fire & rescue roles.
• A-side: "Alpha" side, Front of the fire building, usually front door facing street, side with visible address but may be facing parking area where first apparatus arrives; other sides labeled B, C, D in a clockwise manner, as necessary when speaking of or staffing structure fire sectors.
• Above-ground storage tank: Storage tank that is not buried. Compare underground storage tank. 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.
• Accelerant: flammable fuel used by some arsonists to increase size or intensity of fire. May also be accidentally introduced when HAZMAT becomes involved in fire.
• Accountability: The process of emergency responders checking in with or announcing to an incident commander or accountability officer that they have arrived on scene of an incident. Through the accountability system, each person is tracked throughout the incident until released from the scene by the incident commander or accountability officer. During an extended operation, an accountability "roll-call" may be performed at specified intervals. 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.
• AFA: Automatic fire alarm/actuating fire alarm/activated fire alarm
• Aircraft rescue and firefighting : a special category of firefighting that involves the response, hazard mitigation, evacuation and possible rescue of passengers and crew of an aircraft involved in an airport ground emergency.
• Air-track: The route by which the air enters the structure to the fire and the subsequent path the heated smoke takes to exit the structure. Also referred to as flow path.
• Active Service Firefighter : A defunct term used prior to 2018 for firefighters, who were People's Armed Police personnel and were treated as military personnel.
• Alarm: system for detecting and reporting unusual conditions, such as smoke, fire, flood, loss of air, HAZMAT release, etc.; a specific assignment of multiple fire companies and/or units to a particular incident, usually of fire in nature; centralized dispatch center for interpreting alarms and dispatching resources. See fire alarm control panel.
• All companies working: Status report at fire scene indicating that available manpower is busy, and more resources may become necessary if incident is not controlled soon.
• Ammonium nitrate: component of ANFO; contents of two ships that exploded in Texas City disaster, killing over 500 people, including all 27 volunteer firefighters at the scene; as well as in warehouses in the port of Beirut.
• ANFO: Ammonium nitrate and fuel oil combination making a high explosive.
• Apparatus / Appliance : A term usually used by firefighters describing a piece of mobile firefighting equipment, such as a pumper, a tanker, a ladder truck, etc.
• Arson: the crime of maliciously setting fire to property, especially a dwelling. Punishable in various degrees, depending upon the circumstances. Occasionally occurs as a psychotic act of a mentally ill firefighter.
• Authority having jurisdiction : organization or agency with legal authority over a given type of incident ; may change or overlap as incident changes, as where fire becomes arson investigation once danger is over, or motor vehicle accident becomes police business after vehicle extrication, fire, and HAZMAT issues are complete.
• Auto-aid: An enhanced form of mutual aid agreement between one or more departments or districts, under which a mutual aid response can be dispatched "automatically" without prior permission from a chief officer.
• 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.
• Auto ignition temperature : The temperature at which a gas/air mixture will self-ignite. As the temperature increases the lower flammable limit will approach zero. Also known as spontaneous ignition temperature.
• 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. Incident commander must assess available flow to determine whether additional apparatus or streams are required. See ''Fire flow requirement.''

  B

• BA set: Breathing apparatus set consisting of a face-mask and compressed air cylinder. Two types SDBA and EDBA. SDBA or standard duration breathing apparatus has one cylinder and supplies about 30 minutes of air. EDBA or extended duration breathing apparatus has two cylinders and supplies about 60 minutes of air.
• Backdraft: A fire phenomenon caused when heat and heavy smoke accumulate inside a compartment, depleting the available air, and then oxygen/air is re-introduced, completing the fire triangle and causing rapid combustion.
• Backfiring: Also known as a "controlled burn," it's a tactic mostly used in wildland firefighting associated with indirect attack, by intentionally setting fire to fuels inside the control line. Most often used to contain a rapidly spreading fire, placing control lines at places where the fire can be fought on the firefighter's terms. This technique has been used in rapidly spreading urban fires, especially in San Francisco following the 1906 earthquake.
• Back burning: Australian term, for backfiring, above.
• Backflow preventer: Automatic valve used in hose accessories to ensure water flows only in one direction. Used in permanent fire department connections to sprinklers and dry standpipes, as well as portable devices used in firefighting.
• Backstretching: Laying a supply line from the vicinity of the fire structure to a hydrant.
• Bank down: What the smoke does as it fills a room, banks down to the floor, creating several layers of heat and smoke at different temperatures—the coolest at the bottom.
• Bail-out. The act of completing a quick egress away from a fire room, on a ladder. This is done if flashover conditions are imminent.
• Boiling liquid expanding vapor explosion : Explosion of a pressure tank containing an overheated material when the vapor expansion rate exceeds the pressure relief capacity. If the contents are flammable, the rapidly released vapor may react in a secondary fuel-air explosion, usually violent and spectacular.
• Bomber: Australian term for fixed wing fire-fighting aircraft. Also called "water bomber" or "borate bomber".
• Box : a term used to describe a preplanned response to an incident type and location, ensuring appropriate personnel and equipment are available as quickly as possible. The term is typically combined with a number identifying the specific response instructions. For example, "Box 25598" corresponded to Alvernia High School in Chicago and enumerated firefighting companies to be dispatched when an alarm from that location was received. Historically, box instructions were listed on cards and dictated by building types and geographic area. A building known to have hazardous materials will trigger deployment of HAZMAT equipment in addition to standard truck and engine companies. The box can also include escalation instructions. Modern computer-aided dispatch supports fine-grained variation to the box based on times of year, weather, or severity of incident. Incident commanders will instruct dispatchers to "fill the box" when the initial investigation of an alarm confirms a working fire and all the planned companies are necessary, or to "terminate the box" if the incident is resolved and the responding companies are no longer needed. The box term derives from the historical use of numbered fire alarm pull boxes that were commonplace in cities during the 19th and 20th Centuries.
• Buffer zone: The creation of a 'buffer-zone' implies the use of 3D defensive actions to reduce potential for an ignition of fire gases in the immediate area of a structure occupied by firefighters. This may create a temporary and more local zone of safety for firefighters, although offering far less protection than a 'safe-zone'.
• Buggy: A term usually used for the chief's vehicle, a reference back when the chief would respond in a horse drawn buggy. In wildland fire "buggy" is slang for "crew transport." Type I crews are referred as "Interagency Hotshot Crews" that have crew transports permanently assigned to them and almost all the transports use the same model configuration with no or little differation for the different agencies that have hotshot crews. Hotshot crews have two crew transports and a superintendents vehicle, which is a pickup sized with a utility box configuration. Hotshot crews are not the only type of crew and less experienced crews are called Type II crews that may not have vehicles permanently assigned to them. It is rare to hear a crew transport called same. Almost everyone on a wildland fire will say "buggy" instead.
• Burn building: Former official US term for a live training structure. Still commonly used in the US, although the term was discontinued for official use in the US in 2007.
• Bus: Another term for ambulance.
• Bushfire: Australian term, for wildfire, below.