Glossary of Firefighting - B

B

• BA Set: Breathing Apparatus Set consisting of a face-mask and compressed air cylinder
• 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.
• Backfiring: A tactic 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.
• 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 (FDC) to sprinklers and dry standpipes, as well as portable devices used in firefighting.
• Backstretching: Doing a Fire to Hydrant procedure.
• 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 conditional are imminent.
• Boiling liquid expanding vapor explosion (BLEVE): Explosion of a pressure tank containing an overheated material when the vapor expansion rate exceeds the pressure relief capacity (e.g., steam boiler or LPG tank). If the contents are flammable, the rapidly released vapor may react in a secondary fuel-air explosion. (Big Loud Explosion, Very Exciting.)
• Bomber: Australian Term, for fixed wing fire-fighting aircraft. Also called "water bomber".
• Box (Alarm): A mailslot or other file system containing a notecard with a planned response to an incident type. For example, a reported structure fire on Some Road would be tagged with Box 6; the notecard in Box 6 would contain the list of apparatus from various fire stations that should be dispatched to that incident. Assigning Boxes to areas (or even specific structures) significantly facilitated the process of getting the right tools to the right place on the initial dispatch, and helped eliminate the guesswork of "which department has what" on the fire scene. Boxes later evolved to contain escalation procedures - on the "2nd alarm", the Box would contain the next group of apparatus from various fire stations, etc. Modern CAD systems now abstract the Box Alarm concept, and allow box definitions to be triggered based on arbitrary geographic area, time of day, incident type, weather, and any other planned situation. For a given hydranted area, the "Summer" box will contain the usual response of Engine, Truck, and Rescue companies. In the winter, however, the box may be modified (automatically, or manually) to include Water Tankers on the initial dispatch, to handle the case of frozen hydrants. The term "Box" comes from the fire alarm pull boxes that were commonplace in major cities for well over fifty years. This was a telegraph system that involved bells to ring out the box number. This system was in place from the 1920s (or earlier) to well into the 1960s and 1970s in some cities. Boston was one of the first (if not THE first) major U.S. Cities to have a telegraph alarm system. They installed it in 1852. The Boston Fire Department still uses this system of paper rolls and bells. The modern use of "box cards" based upon an imaginary box location for dispatch or move up is often known as the "Phantom Box System".
• Bus: another term for ambulance.
• Bushfire: Australian term, for Wildfire, below.