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 (often liquid) used by some arsonists to increase size or intensity of fire. May also be accidentally introduced when HAZMAT becomes involved in fire.
•
Accelerator (also exhauster): portion of dry-pipe system that bleeds air or shunts air pressure below the clapper valve when sprinkler pipe pressure drop is sensed, thus speeding operation of the valve to fill the system with water.
•
Adapter: plumbing accessories for connecting hoses and pipes of incompatible diameter, thread, or gender. See also reducer, increaser, double male, double female, water thief. May contain combinations, such as a double-female reducer. Adapters between multiple hoses are called wye, Siamese, or distributor, which see below.
•
Aerial apparatus: fire truck having an attached extension ladder, nozzle, man-lift-bucket, or similar device raised using power from the truck. May also carry other portable ladders and tools.
•
Air monitoring meter: electronic device for measuring the presence of one or more chemicals in air, such as oxygen, carbon monoxide, hydrogen sulfide or volatile organic compounds; may have preset danger threshold alarms.
•
Airbags: (1) inflatable device used for lifting or spreading; (2) vehicle safety device with potential explosion hazard during vehicle extrication if not already blown.
•
Airpack: jargon for self-contained breathing apparatus (SCBA).
•
Alarm: Alarm:
•
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 28 volunteer firefighters at the scene.
•
ANFO: Ammonium Nitrate Fuel Oil combination making a high explosive.
•
Apparatus: Fire engines, trucks, tankers, and combinations; can also refer to other equipment such as the SCBA.
•
APW: Air-pressurized water fire extinguisher, partially filled with water and then pressurized with an air pump; popular in the US in the 2 1/2-gallon size, rated 2A.
•
Aqueous Film-Forming Foam (AFFF): (pronounced "A-Triple-F", also called "Class A"): bubbles that act as surfactant to coat and penetrate ordinary fuels (e.g., wood, paper) to prevent them from burning at normal temperatures; also used on "Class B" (oil/gasoline) fires to spread a non-volatile film over the surface of the fuel. Applied using eductor or Compressed air foam system (CAFS) and pumped through firehose to a foam nozzle (or sometimes a less-effective fog nozzle).
•
Arson: the crime of maliciously (or perhaps recklessly) setting fire to property, especially a dwelling. Punishable in various degrees, depending upon the circumstances.
•
Attack hose: A use classification of a fire fighting hose connected to output of a pump or other pressure source (e.g., gravity). Firehose used to apply water or other fire fighting agent directly to a fire or burning substance. Typically of 2 1/2 inches (65 mm) diameter or less.
•
Attic ladder: narrow, collapsible ladder used to access an attic space via a scuttle hole, which are often found in closets and other narrow passages. Also known as a closet ladder.
•
Authority Having Jurisdiction (or AHJ): organization or agency with legal authority over a given type of incident (e.g, fire, EMS, SAR, arson, HAZMAT); 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.
•
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).
•
Automatic sprinkler: system of valves and pipes for automatically directing water to a fire when it is detected. May be normally pressurized with water ("wet") or with air ("dry"), depending upon the application. When a sprinkler-head (or sensor) detects fire/heat, the valve opens, releasing the water (hopefully onto the fire).
•
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. See Fire flow requirement.
B
•
Backdraft: A fire phenomenom 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.
•
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.
•
Bank down: What the smoke does as it fills a room, banks down to the foor, creating several layers of heat and smoke at different temperatures -- the coolest at the bottom.
•
Bed ladder: the non-extending section of an extension ladder.
•
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 propane tank). If the contents are flammable, the rapidly released vapor may react in a secondary fuel-air explosion.
•
Booster hose: Small-diameter fire hose (3/4-1 inch), often carried on booster reel, preconnected to pump of an engine (and the booster tank) for putting out small fires near the truck without having to connect to a hydrant; easily recovered with a motorized reel.
•
Bresnan cellar nozzle: Rotating nozzle tip having two or more outlets forming water jets that propel the tip while spraying water in a circular pattern; conveniently attached to several feet (a meter) of rigid pipe with handles or legs for supporting the nozzle while it is suspended through a hole in the floor above.
•
Bulk tank: Large tank designed to be transported to an incident and left; larger than a tote tank.
•
Bunkers (or "bunker gear"): colloquial term for protective pants and boots kept near a firefighter?s bunk (cot) for rapid deployment; more modernly includes firefighting jacket. Basis for command to "Bunker up!" in preparation for hazardous duties. May also refer to entire protective clothing ensemble.
C
•
Cellar fire: Cellar fires are difficult to attack directly because firefighters have to pass through the hot gasses and smoke accumulated on the cellar's ceiling to gain access to the cellar space. Cellars typically do not have good emergency egress points, adding to the danger.
•
Cellar pipe: Cellar Nozzle. A distributing type nozzle that is inserted through an opening in the floor and into the space below, typically a basement or cellar. The nozzle directs a broken stream horizontally, either extinguishing or controlling the fire enough to allow a direct attack to be safely made. Can also be used on top of other containers.
•
Charged line: fire hose under pressure from the pump at the engine.
•
Check valve: see backflow preventer
•
Chimney fire: Fast and intense fire in a chimney flue in which accumulated creosote and other combustion byproducts ignite.
•
Class A, B, C, D, K: Classes of fire extinguisher and corresponding type of fire they extinguish.
•
Closet hook: pike pole under 5 ft long
•
Closet ladder: see Attic ladder.
•
CO2 extinguisher: Fire extinguisher that releases carbon dioxide gas to smother and cool a fire, such as a flammable liquid.
•
Cockloft: structural space above ceiling and below rafters, often connecting adjacent occupancies and permitting fire to spread laterally, often unseen.
•
Collapse zone: a relatively poor place to park the engine near a burning structure. Estimated as an area one and a half times the height of the fire building.
•
Company: two or more firefighers arranged as a team.
•
Crash Tender: a pump capable of spraying foam used at airports.
•
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.
D
•
Dalmatian: "Firehouse dog."
•
Dead lay: A load of hose on a pumper, but not connected to a pump outlet. Often used for larger supply lines.
•
Deck gun: A master stream device mounted to top deck of pumper.
•
Deflagration: An explosion with a propagation front traveling at subsonic speeds, as compared to supersonic detonation.
•
Deluge system: Type of sprinkler system in which sprinkler heads do not have individual valves, and the water (or other extinguishing agent) is disbursed from all sprinkler heads simultaneously when a central (or zoned) valve is triggered by a sensor (or manually). Typically reserved for industrial areas where rapid fire spread must be prevented at the cost of damaging non-burning materials.
•
Denver Door opener: heavy pry bars connected with a hinge, one with an adjustable foot, used for prying open doors.
Denver tool (also called TNT tool): A combination axe, sledgehammer, pry tool, ram, and D-handle pull tool used to gain forcible entry to buildings, automobiles, etc. during emergency situations.
•
Denver tool (also called TNT tool): A combination axe, sledgehammer, pry tool, ram, and D-handle pull tool used to gain forcible entry to buildings, automobiles, etc. during emergency situations.
•
Detection system: See Alarm system.
•
Detergent foam: See Aqueous Film Forming Foam.
•
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.
•
Distributor pipe: Portion of fire hydrant or sprinkler system connecting main loops to smaller loops where outlets are located.
•
Double female: firehose adapter for connecting two "male" couplings together; may also adapt different sizes on either side.
•
Double male: firehose coupling adapter with two male-threaded connectors back-to-back; used for connecting two female couplings together.
•
Draft: The process of pumping water from a 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.
•
Dry chemical: A fire extinguishing agent. It works by breaking the chemical chain reaction in the "fire tetrahedron".
•
Dry hydrant: A fire hydrant with a valve located at the bottom of the barrel, near the water main. The barrel of the hydrant remains dry until used. The prevents the hydrant from freezing in sub-zero temperatures.
•
Dry powders: Fire extinguishing agents for use on flammable metals. Each agent is typically designed for use on a either a single metal or very similar metals.
•
Dry sprinkler: A sprinkler system having pressurized air (rather than water) in the distribution pipes until a heat-activated sprinkler head opens and releases the pressure, which opens a water valve (and possibly an accelerator valve) to flow water to the open head; used where the protected premises are not heated during freezing temperatures or where pressurized water in overhead sprinkler pipes could create another hazard.
E
•
Eckert hook: Sharp hook on pike pole for cutting metal siding or roofs.
•
Eductor: Suction device operated by hose pressure to pull fluid from a reservoir and mix it with the hose stream; often used to add foaming or other materials to water streams.
•
Ejector: see Smoke ejector.
•
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.
•
Elevator key: control panel override key to take elevator car to desired floor. May also refer to special tool used to open elevator shaft-protection doors from outside.
•
EMS: Emergency medical service.
•
Encapsulated suit: HAZMAT protective clothing used with SCBA inside the suit to protect a firefighter (HAZMAT technician) from gaseous contaminants.
•
Encoder: (1) Device for converting an input to a coded output; (2) tone-generating system for broadcasting one or more tone codes on a radio frequency to alert selected pagers and alarms; (3) alarm-system component that transmits coded sensor and subscriber information to a monitoring center to be processed into address and alarm-type information.
•
Engine house: Early form of firehouse when pumper was the only dedicated fire apparatus.
•
Engine pressure: The pressure in a fire hose measured at the outlet of the pump.
•
Engine: A truck outfitted for firefighting, specifically one outfitted to pump water. Generally, vehicles outfitted to pump water are called engines, while those which do not pump water (ladder trucks, tankers, rescues, for example) are not. Many rural fire engines carry a reservoir of water to pump, and use drafting and tankers to obtain further supply. Historically, an "enjin" was a machine that only pumped water.
•
Enhanced 9-1-1: Electronic system for automatic correllation of physical telephone lines with information about the location of the caller -- a useful tool for dispatchers when the caller has an emergency but cannot speak.
•
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.
•
Exothermic reaction: Chemical reaction giving off heat in the process, such as combustion.
•
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.
•
Extension ladder: A 20-60 foot ladder with one or more movable sections that extend beyond a base section, typically using a halyard rope and pulley mechanism for lifting and locking cams to latch the moving sections at a selected height.
•
Extinguisher: Device containing fire suppressant, often pressurized to expel suppressant when triggered by operator or an automatic release mechanism. Important to properly select type of extinguisher appropriate to type of material burning (wood, grease, electrical, etc). May be portable or permanently installed for special suppression purposes, such as fires in aircraft engines, restaurant exhaust hoods, or computer rooms.
•
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.
F
•
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 others inside a structure; an implementation to support the Two-in, two-out rule; may have specialized training, experience and tools.
•
FFFP: Fluoroprotein film forming foam.
•
Fire alarm control panel: System for receiving and announcing location of fire based upon input from smoke, flame or heat detectors, or manual call points or pull stations.
•
Fire axe: See pickheaded axe.
•
Fire code ( Fire safety code): regulations for fire prevention and safety involving flammables, explosives and other dangerous operations and occupancies.
•
Fire department keys: Special keys provided to firefighters to access a lockbox, located on some commercial buildings, containing additional keys required for entry or other safety features.
•
Fire engineering: Scientific design of materials, structures and processes for fire safety
•
Fire escape: A building structure arranged outside to assist in safe evacuation of occupants during an emergency; may connect horizontally beyond a fire wall or verically to a roof or (preferably) to the ground, perhaps with a counter-weighted span to deny access to intruders.
•
Fire extinguisher: See Extinguisher above
•
Fire flow: The amount of water being pumped onto a fire. A critical calculation in light of the axiom that an ordinary fire will not go out unless there is enough heat being removed by enough water.
•
Fire grenade: glass bottle filled with carbon tetrachloride or similar fire extinguishing fluid; meant to be thrown and shatter at base of fire to mix with air to produce non-combustible mixture; Similar to extinguishers comprised of glass fixtures with spring-loaded clapper released by heat-fusible link. Limited effectiveness, and phased out in 1950s when better extinguishers became available.
•
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 hydrant: See hydrant.
•
Fire hydraulics: The study of pumps, hoses, pipes, accessories and tools for moving water or other extinguishing agents from a water supply to a fire.
•
Fire inspector: A person responsible for issuing permits and enforcing the fire code, including any necessary premises inspection, as before allowing (or during) a large indoor gathering.
•
Fire line: A boundary of a fire scene established for public safety and to identify the area in which firefighters may be working.
•
Fire load (Btu/sq ft): An estimate of the amount of heat that will be given off during ordinary combustion of all the fuel in a given space; e.g., a bedroom or a lumberyard.
•
Fire marshal: Administrative and investigative office for fire prevention and arson investigatation.
•
Fire point: temperature at which materials give off flammable gases that will sustain fire, typically higher than flash point. Temperature at flashover.
•
Fire prevention: Fire safety; standards for minimizing fire hazards.
•
Fire station alert system: fire department dispatching system using radio controls to activate remote signals at designated fire stations and to transmit emergency information via audio or digital channels.
•
Fire streams: Water (possibly mixed with foam) emitted at nozzle and directed at burning materials.
•
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.
•
Fire-resistant: Materials designed or treated to have an increased fire point.
•
Firefighter Assist and Search Team: See FAST.
•
Firefighter: People who respond to fire alarms and other emergencies for fire suppression, rescue, and related duties. Formerly called "firemen", but modern term includes women as well.
•
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.?
•
Firehose: See also hose, below.
•
Firehouse: Another term for Fire station. Where fire apparatus is stored and where full-time firefighters work.
•
Fireman's key: set of tools used for opening elevator doors from the lobby during rescues; come in many different shapes and sizes, each designed for a specific elevator type.
•
Fit test: Periodic test of how well the facepiece of an SCBA fits a particular firefighter.
•
Flammable range, limits: The percentage mixture of fumes with air that will sustain fire; outside the limits the mixture is either too lean or too rich to burn.
•
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.
•
Fly: The moving portions of an extension ladder.
•
Fog nozzle: A nozzle that discharges water in small droplets. Oftentimes, the nozzles are adjustable, permitting the pattern to range from a straight stream to a narrow fog to a wide fog stream. Can also be designed to automatically adjust pressure depending upon selected pattern.
•
Fog Stream: A fire stream characterized by small droplets of water. The droplets are unable to travel very far, but absorb heat very quickly because of the high surface area they present.
•
Foot valve: Backflow preventer at inlet of suction hose used in drafting; helps avoid losing prime by keeping water from running back out of the suction hose.
•
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.
•
Frontage: The size of a building facing a street.
•
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.
G
•
Gamewell: brand of wind-up, fire alarm telegraph system for sending coded pulses to alert central alarm station of fire alarm activation; often still found in red boxes on street corners.
•
Gate valve: See also "Hydrant Gate". Valve in which the shutoff device slides across the flow of liquid to obscure the orofice, usually activated by a screw mechanism. Compare "ball valve."
•
Glas-Master tool: brand of specialized vehicle extrication tool, most notibly including a glass cutting saw for removal of automobile windshields.
•
GPM method ("gallons per minute"): Calculation of how much water, in GPM, will be necessary to extinguish a given volume of fire, under the circumstances (e.g., fuel class, containment, exposures, etc).
•
Grease fire: A fire involving any manner of cooking oil or other flammable cooking or lubricating materials.
•
Ground ladder: A portable ladder designed to rest on the ground. Compare aerial ladder and roof ladder.
H
•
Halligan tool (or "Hooligan"): forcible entry tool with a pointed pick and a wedge at right angles on one end of a shaft and a fork or cat's paw at the opposite end. Used in combination with maul or flat-headed axe for forcing padlocks, doors and windows. Based upon original design by Hugh Halligan of FDNY. Forms "the irons" when nested with a flathead axe. Various shaft lengths provide mechanical advantage. Derived from the claw tool (fork and hook).
•
Halon: chemical gas fire extinguishing or liquid agent for diminishing the combustion reaction rate by acting as a thermal ballast; used mainly in closed computer rooms, aircraft, and other high-value installations where corrosive chemicals or water extinguishers are judged inappropriate. Effective at low concentrations (5%) as compared with CO2 (34%). Being phased out with suitable replacements in most applications, with very restricted exemptions, due to international environmental concerns with this and other CFCs.
•
Halyard: utility rope for raising or lowering moving parts of extension ladder.
•
Hard suction hose: Non-collapsible sections of hose, usually 10 feet long, used when drafting.
•
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.
•
Higbee cut (Higby cut': A tapered thread termination in a firehose coupling for avoiding cross-threading, the location of which is indicated by a notch cut into a single lug on a hose coupling. If the notches are aligned on mating couplings, the Higbee cuts are aligned and the threads will immediately engage when the swivel fitting is turned.
•
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.
•
High-rise pack: Hose bundle prepared for carrying to a standpipe in a high-rise building, usually consisting of 50 or more feet of 1 3/4-inch hose and a combination nozzle.
•
High-rise pack: A shoulder load of hose with a nozzle and other tools necessary to connect the hose to a standpipe.
•
Hook: forged steel hook at end of insulated pole of varying lengths; used for piercing and pulling building materials away from walls and ceilings. Similar to nautical gaff hook. Short hook with a pointed tip is a pike pole; longer hook on a San Francisco hook; two offset hooks on either side of tip is a universal hook; long p-shaped hook is a Boston rake for pulling plaster and lath; short hook with claw on opposite side of tip is either a gypsum hook or the narrower ceiling hook; pike pole with a short handle is a somewhat useless closet hook.
•
Hose bed: part of fire engine (or hose wagon) where hose is stored for transport and easy access; stocked in layers or rows for quick selection of the desired length, diameter and type of hose; may include hoses "pre-connected" to pump outlets on the engine.
•
Hose bridge: mechanical ramps permitting vehicle tires to roll over top of hose without pinching or damaging the hose. Sudden hose-pinch can cause dangerous backpressures in a running hose and at the pump and release of the pinch can cause a staggering surge at the nozzle end.
•
Hose cart: See Hose wagon.
•
Hose coupling: rigid interlocking end-pieces on fire hose; used for connecting hose to hydrants or fire engine pumps and other hose appliances (nozzles, wyes, manifolds, strainers, etc); standardized sizes and threads or other (non-threaded) pressure-sustaining interlocks (e.g., "Storz" or other "quarter-turn" connectors); lugs, cams, or pins are used to tighten and loosen couplings by hand or with a hose wrench.
•
Hose roller: rigid frame with rollers designed to fit over windowsill or roof parapet to prevent chafing as hose is pulled across it. Can also refer to a machine designed for rolling hoses in preparation for storage.
•
Hose tower: structure for hoisting hoses to permit them to drain and dry.
•
Hose wagon: a handcart, vehicle, or trailer adapted for storing and hauling hose and related equipment; used by industrial fire brigades with large buildings, or where supplemental hoses are needed beyond that normally carried on a fire engine; also used for taking attack hose into a high-rise and for returning dirty, wet hose to the station instead of loading the hose bed with it. Vehicular hose wagon may carry 1,000 to 3,000 feet of hose. May also include small booster pump.
•
Hose wrench: tool for holding hose couplings against opposite turning forces (tighten/loosen); may be one of several designs for different shapes of cleats or lugs on couplings (round, flat, recessed, etc), and also of different sizes according to the couplings being handled, and come in various combinations to minimize the number of different tools necessary on the fire ground.
•
Hose: flexible conduit for moving liquids under pressure; made of various materials including cotton, rubber or plastic (such as polyvinyl chloride, PVC); construction may be braided, woven, wrapped or extruded, often in layers (liner and jacket); hose construction and size differs according to its intended use (e.g., hard suction, attack, forestry, booster); typically stocked in standard lengths and coupled together with standardized fittings. See hose coupling.
•
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.
•
Hurst tool: See Hydraulic spreader.
•
Hydrant Assist Valve: a valve connected to the hydrant by the first due engine allowing the second due engine to boost the pressure in the intake line. Used for hydrants with low pressure, attaching multiple engines to one hydrant, or boosting pressure in the intake line to accomidate for friction loss.
•
Hydrant Gate: A gate valve used to control water flow through one of the discharge ports on a hydrant with two or more ports. Typically, one fire hose is initially connected to one discharge and the hydrant gate is connected to one or more of the other outlets. This allows a second hose to be connected to a hydrant that is flowing water without shutting down the main valve to make the connection.
•
Hydrant wrench: tool for opening valve of fire hydrant; may be simple spanner, box wrench, or adjustable wrench, or a specialized tool for use on "anti-vandalism" valves. For example, some valves require a magnet to activate a cam in order for the valve to be turned on.
•
Hydrant: pressurized water source for fire engine. May also be a "dry hydrant" for drafting from static water source. Compare "standpipe".
•
Hydraulic spreader, (Jaws of Life): mechanical levering device with hydraulic cylinders powered by a pump; used for forcible entry or spreading vehicle or structure parts to permit extrication of a victim. Also called Hurst Tool which is a type that includes cutter and ram/jacking features.
I
•
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: Officer in charge of activities at an incident. See Incident Command System.
•
Indian pump: a brand of five-gallon water can with a short hose and hand pump used in wildland firefighting.
•
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.
•
Intake: Part of pump where water enters when pump forms partial vacuum.
•
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.
•
Irons, or Set of irons: Pairing of a flat-head axe and a Halligan tool. A common combination used for interior fire attack.
J
•
J-bar: a stiff, j-shaped tool for reaching an inside door handle.
•
Jack-knifing: jargon for position of articulated aerial ladder such that tractor is at an angle to the trailer; provides improved stability when ladder is hoisted, rotated and extended.
•
Jaws of Life: A Hurst tool. See hydraulic spreader.
•
Jet siphon: A venturi appliance used for moving large amounts of water from one reservoir tank to another by pumping a small amount of pressurized water into the jet to create a vacuum to move larger amounts of water.
K
•
K-tool: A forcible entry tool for disabling cylinder locks; used with a Halligan.
•
Kelly tool: a prying tool much like a Halligan tool without the right-angle pointed tip.
L
•
Ladder company: A group of fire fighters, officers and engineers that staff a ladder truck.
•
Ladder pipe: Nozzle attached to aerial ladder and used to direct heavy stream from advantageous height.
•
Ladder truck: A truck outfitted for fire which is operated by a ladder company, and in most cases is not outfitted to pump water. Not to be confused with engine.
•
Large Diameter Hose: (LDH) Fire hose with a diameter of 4 inches or greater. LDH is typically used to supply water from a fire hydrant to fire apparatus such as an engine or tanker.
•
Level A, B protective clothing: Different levels of encapsulation of firefighters used during HAZMAT incidents to minimize contamination.
•
Level I, II, III Incident: A HAZMAT term denoting the severity of the incident and the type of response that may be necessary, where Level III is the largest or most dangerous.
•
Life line: A trademark for a wireless emergency call unit that triggers a telephone call to an emergency dispatcher when a button is pressed.
•
Life net: Portable net for attempting to catch victims falling or jumping from upper floors of burning structure.
•
Life safety code: NFPA publication.
•
Life safety line: A rope used where its failure could result in serious injury; a rope used for connecting a firefighter/rescuer to a fixed anchor point or to another person.
•
Line loss: See friction loss.
•
Live line: A fire hose under pressure from a pump. Also, an energized electrical line that may cause a hazard to firefighters.
•
Loaded stream: A hose stream that has had a surfactant added to assist in penetrating burning materials.
M
•
Mass casualty: 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 box: An alarm system in which a local fire-alarm system triggers a fire alarm box (the master box) to signal the fire condition to a central monitor.
•
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.
•
Medium-diameter hose: A hose with diameter between 2 1/2 and 4 inches.
•
Muliple 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.
•
Multigas detector: Measuring device designed to indicate concentrations of four selected gases, such as oxygen, carbon monoxide, volitile organic compounds, hydrogen cyanide, etc.
•
Mutual aid: An agreement between nearby fire companies to assist each other during emergencies by responding with available manpower and apparatus.
N
•
NFPA: The National Fire Protection Association, which sets a number of standards for *firefighting, equipment, and fire protection in the United States, and also adopted in many other countries.
•
NIFTI: Naval InFrared Thermal Imager. A device used aboard naval ships to help locate hotspots where fire or personell may be located in a dense smoke environment.
•
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.
•
Nozzle reaction: The force felt when water is pumped through a nozzle, e.g., 350 US gallons per minute (22 L/s) would produce a force of 40 pounds force (180 N) against the firefighter holding the nozzle.
•
Nozzle tip: Portion of firehose that forms the fire stream as it leaves the hose. Can be solid, fog, or other specialty nozzle (e.g., piercing, Bresnan cellar nozzle, wand tip, etc).
•
Nozzle: A device attached to the end of a fire hose that directs, shapes and regulates the flow of the water or fire fighting agent pumped into the hose. May have a control valve.
O
•
Occupancy class: General categories of structures for purpose of safety planning, such as for hospital, assembly, industrial, single-family dwelling, apartment building, commercial, etc. Further broken down by types of hazards associated with particular occupancies, such as gas stations.
•
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.
•
Occupant use hose: Light-weight firehose coupled to standpipe for emergency use by building occupants prior to arrival of firefighters. Often accessible by breaking glass to unlock secure enclosure.
•
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.
•
On-call: Personnel who can be summoned (and paid) when necessary to respond to an incident; a type of "volunteer" fire department.
•
Open-circuit SCBA: See SCBA. Exhaled air is not reused by the system.
•
OSHA: U.S. government agency concerned with regulating employee safety, particularly in hazardous occupations such as firefighting.
•
Outside stem and yoke valve (OS&Y): Type of gate valve actuator arranged such that the valve stem moves in and out of the handle, thus externally indicating whether the valve is open or shut, unlike the more common gate valve wherein the stem rotates and only the gate moves up and down inside the fixture.
•
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.
P
•
Panic doors, panic hardware: Fire safety appliance permitting locked doors (typically self-closing) to be opened from the inside when pressed with sufficient force, thus permitting a person to open the door without having to turn a knob or lever.
•
PASS device, personal alert safety system: An alarm device which signals that a firefighter is in trouble. It can be activated manually by the firefighter, or activates automatically if the firefighter stops moving. May be integral to SCBA or separately activated.
•
Passport (accountability): System in which each firefighter has an identification document that is collected by the person in charge of accounting for the current location of the respective individuals, and returned to the firefighter when he or she leaves the dangerous area.
•
Personal alert safety system: See PASS device in firefighting equipment terms.
•
Personnel accountability report: End-result of personnel accountability system. Best report is all hands, AOK worst is squad missing.
•
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.
•
Pickheaded axe: Standard fire axe having a 6 or 8 pound steel head with a cutting blade on one edge and a square, pointed pick on the opposite side. Come in various handle lengths.
•
Pike pole: See Hook.
•
Plec-Tron: Jargon, brand-name of early radio-frequency paging system for summoning firefighters.
•
Pompier ladder: A style of ladder that is also known as a "Scaling Ladder". It is used to climb from one window to another. It differs from other ladders in that it does not rest on the ground it instead uses a large hook at the top to attach to a window sill. The word "Pompier" is French for fireman.
•
Portable water tank: Collapsible reservoir used for storing water transported to fireground by tanker. May be inflatable or supported by a frame.
•
Positive Pressure Ventilation (PPV): Ventilation of an area by the use of a fan to push clean air into that space and controlled use of openings for the escape of smoke and gasses.
•
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.
•
Post indicator valve (PIV): A type of valve used for underground sprinkler shutoff, having a lockable actuator atop a post with a window indicating "open" or "shut" status of the valve.
•
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, followup analysis and recommendations for actions to be taken in case of specific incidents.
•
Preconnect: Firehose on a fire engine which has one end connected to a pump outlet, and usually a nozzle attached to the other end. May also be a preconnected inlet hose (e.g., soft suction). Reduces steps at scene of fire.
•
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 engineer, 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.
•
Pumper: Vehicle apparatus for pumping water and other fire suppressants. See fire engine.
•
Pyrolysis: Process of converting a solid substance to combustible fumes by raising its temperature. See also vaporization of liquids.
Q
•
Quint: Type of firefighting apparatus performing five jobs. The Quint Truck is both a Pumper and a Ladder Truck. "Quint" means "five" and this truck has five main items: 1. a pump, 2. water tank, 3. hose, 4. ground ladders, and 5. an aerial ladder.
R
•
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 entry team: See FAST.
•
Rapid intervention team: See FAST.
•
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.
•
Reducer: Plumbing adapter for connecting hoses of two different diameters; may also be double male or double female connections of different sizes.
•
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.
•
Roof ladder: A single-section ladder with hooks on one end. The hooks are put over the ridge or peak of a roof to hold the ladder in place. Compare with aerial ladder and ground ladder.
•
Rope hose tool: Short strap or rope with a hooks at both ends for wrapping around a chareged hose to secure it in position or to assist in moving it.
•
Run card system: A system of pre-planning for fire protection in which information about specific detectors, hazards, or other emergency response plans is indexed by location, for rapid reference during an alarm.
S
•
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.
•
SAR: See Search and rescue.
•
SCBA: Self Contained Breathing Apparatus, or air-pack, worn by firefighers to protect against breathing toxic fumes and smoke, or where the air has insufficient oxygen. Often incorrectly called "oxygen mask" by laypersons. Typically of open circuit style, with a supply of compressed air, where expired air is exhausted, rather than closed circuit where it is filtered, re-oxygenated from compressed oxygen, and inhaled again — which is used where an air supply is needed for an extended period (up to four hours).
•
Scuttle hatch: Ready-made opening in roof that can be opened for vertical ventilation.
•
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.
•
Self-contained breathing apparatus: see SCBA
•
Shoulder load: The amount of hose a single firefighter can pull off a hose wagon or pumper truck and carry toward the fire.
•
Shove knife: semi-rigid metallic blade of various shapes and sizes used for forcing spring latches during forcible entry.
•
Siamese: hose coupling for merging two streams into one, i.e., two female coupling inlets and one male coupling outlet.
•
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."
•
Slip-on: A small water pump and tank that can be temporarily mounted on a pickup or other truck.
•
Small-diameter hose: Generally accepted to be fire hose 3" or less in diameter.
•
Smoke detector: (1) part of a fire alarm system that detects and signals presence of smoke; (2) self-contained household device for same purpose as (1) but with its own noisemaking device.
•
Smoke ejector: Powerful fan for moving large amounts of air and smoke as part of ventilation task while fighting fire in a burning structure. May be operated by electricity or gas motor for positive or negative pressure ventilation.
•
Smoke explosion: See backdraft.
•
Smoke-proof stairwell: Building structure which isolates escape stairwells with relatively fireproof walls, self-closing doors, and positive pressure ventilation, to prevent smoke or fumes from entering the stairwell during evacuation of occupants during a fire or other emergency.
•
Soda-acid extinguisher: Weak water/acid solution inside a pressure vessel which activates bicarbonate of soda when triggered, expelling "water" (mixture) under pressure from the resulting carbon dioxide. Obsolete and often replaced with an APW or multipurpose extinguisher.
•
Soft suction hose, soft sleeve: A short piece of fire hose, usually 10 to 20 feet long, of large diameter, greater than 2.5 inches (65 mm) and as large as 6 inches, used to move water from a fire hydrant to the fire engine, when the fire apparatus is parked close to the hydrant.
•
Solid Stream: A fire stream emitted from a smooth-bore nozzle. This fire stream has the greatest reach and largest drops of water.
•
Solid stream: fire stream from round orifice of nozzle. Compare straight stream.
•
Spanner: rigid tool for tightening or loosening firehose couplings.
•
Special egress control device: Locking device on doors used for delaying opening for short period (10-15 seconds) after release is pressed. Permitted as panic hardware in limited circumstances. May also refer to a security system that releases electronic door locks when a fire alarm is activated, such as in stairwells of a highrise building.
•
Spray nozzle: See fog nozzle.
•
Sprinkler system: fire suppression system in a building, typically activated by individual heat-sensitive valves, or remotely controlled by other types of sensors, releasing water onto the fire. May be "wet" (water-filled) or "dry" (air-pressurized).
•
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: 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.
•
Standpipe: system of pipes inside a building for conducting water for firehose attachments; may be pressurized with water ("wet") or remain "dry" until activated in an emergency; supplied either from a fire hydrant attachment or from a fire engine's pump. Permits firefighters to reach higher levels of tall buildings without having to run hoses up the stairs.
•
Static pressure: The pressure in a water system when the water is not flowing.
•
Steamer connection: A Siamese inlet to a standpipe or sprinkler system. Named for early application of steam engines for pumps.
•
Steamer outlet: Large outlet of fire hydrant.
•
Storz coupling: A type of coupling used on fire hose. The coupling is sexless, and secures with a 1/4 turn of the coupling. The coupling may or may not have some sort of locking device.
•
Straight Stream: A fire stream generated by a combination nozzle, characterized by a long reach and large water drops. It is essentially the narrowest of fog patterns that can be produced.
•
Straight stream: Round, hollow stream formed as water passes a round baffle through a round orifice (e.g., on an adjustable nozzle.) Compare solid stream.
•
Strainer: 1) A large metal device attached to the end of a suction hose that prevents debris from entering the hose or the pump. 2) A stationary accumulation of debris in a moving body of water.
•
Stretch: command to lay out (and connect) firehose and nozzle.
•
Structural fire: Fire involving houses, buildings, or other structures. Urban fire departments are primarily geared toward structural firefighting. The terms structural fire and structural firefighting are often used to distinguish them from wildland fire.
•
Suction hose: A large, semi-flexible and non collapsible hose used to move water from a static source such as a pond, pool or storage tank to a fire pump by means of suction. The whole process is often known as "drafting". Should not be used to connect pressurized hydrants to pumps.
•
Supply line, supply hose, large-diameter hose: fire hose, usually larger than 2.5 inches in diameter, used to transport water from one source to another, such as from a hydrant to a fire engine or from one engine to another. Short pieces of this hose used to attach to a hydrant are often called "Soft Suction" (see above).
T
•
Tag accountability: System in which each firefighter is issued two identification tags, one of which is then collected by a safety officer and held while the firefighter is in a hazardous area. To reclaim the tag, the firefighter must present the matching tag upon exit from the hazard. Any unclaimed tags after an "event" (such as a collapse or explosion) means the corresponding firefighters are missing. May be implemented as passport system in which first tag is presented to staging officer upon arrival (for tracking) and second tag is held by IDLH safety officer, as above.
•
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.
•
Tanker, Tender: Large, mobile tank of water or other firefighting liquid; may be airborne, as used in wildland firefighting, or truck-mounted. Essential in rural areas lacking hydrants.
•
Taxpayer: Description of a fire building used primarily as a private dwelling.
•
Thermal imaging: Ruggedized infrared equipment used by some firefighters to detect hidden people, animals, and heat sources (i.e., fire) when blinded by smoke.
•
Triple combination engine company: apparatus carries water, pumps water, carries hose and other equipment; firefighters who may carry out direct attack or support other engine companies.
•
Truck company: apparatus that carries ladders, forcible entry tools, possibly extrication tools and salvage covers; firefighters who typically carry out tasks with such tools, including roof ventilation; also called "ladder company".
•
Turnout gear: The protective clothing worn by firefighters, made of a fire-resistant material such as Nomex or Aramid, and designed to shield against extreme heat. Sometimes called bunker gear. See PPE. Includes helmet, jacket and boots, and some departments include fire-resistant pants.
•
Turntable: rotating base of an aerial ladder that permits the ladder to be elevated and extended in any direction from a fixed location.
•
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).
U
•
Universal precautions: The use of safety barriers (gloves, mask, goggles) to limit an emergency responder's contact with contaminants, especially fluids of injured patients.
•
Utility rope: A rope not designed or maintained for life safety purposes.
V
•
Valve: mechanical means for stopping and starting flow in a conduit; many types used in firefighting, including gate?, foot?, clapper? (backflow preventers), sprinkler-heads, etc.
•
Vapor suppression: Process of reducing the amount of flammable or other hazardous vapors, from a flammable liquid, mixing with air, typically by careful application of a foam blanket on top of a pool of material.
•
Ventilation saw: A high-powered saw with metal-cutting teeth or disc for quickly making large openings in roofing materials.
•
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.
•
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 may be unpaid or paid when on-call, during incidents, or drills. Often professionally trained and equipped with state-of-the-art equipment.
W
•
Wall-indicator valve: Type of control valve for sprinkler systems which is mounted to an outside wall and indicates "open" or "shut" in an indicator window on the valve body.
•
Water curtain nozzle: A nozzle designed to throw a fan of water droplets to form a "curtain" in an attempt to reduce radiated heat from igniting a nearby exposure.
•
Water drop: A forest fire fighting technique when an aircraft drops a supply of water onto an exposed fire from above.
•
Water flow alarm: An audible alarm indicating that one or more sprinkler heads have been activated.
•
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.
•
Water thief (valve): Type of gated wye having one or more outlets smaller than the largest outlet.
•
Wedges: Wooden blocks for temporary shut-off of activated sprinkler heads or holding doors open during firefighting or rescue operations.
•
Wet pipe sprinkler system: Sprinkler system containing pressurized water rather than air, such that water will flow immediately upon release of a heat-sensitive head.
•
Wet water: Water into which a surface tension reducing agent has been introduced. The resultant mixture, with its reduced surface tension, is more able to penetrate burning product more deeply and extinguish deep seated fire.
•
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 wildland fire terms.
•
Working fire: A fire that is in the process of being suppressed; often a cue for dispatch of additional resources.
•
Wye: hose coupling for splitting one line into two or more outlets, often a larger line split into two smaller ones; often a gated wye having separate valves for each outlet. Not to be confused with Siamese, which is used to bring two smaller lines together into one.
X
•
Y
•
Y-connect: See wye.
•
Yield: What other drivers are supposed to do when they see or hear emergency vehicles approaching with lights and/or sirens activated.
Z
•
Z-adapter: Large hose appliance for connecting supplemental pumps into long supply lines, in the form of a "Z"; may be improvised from two gated wye valves and a double female between two of the gated outlets or from a siamese that has one inlet connected to one outlet of a gated wye.
•
Zone: Section of structure indicated on fire alarm control panel where sensor was activated.
