Distinguish from a firefight, which means a battle with firearms.

A repair locker hose team aboard USS John F. Kennedy (CV 67) combats a controlled fire on the mobile aircraft firefighting training device May 2, 2006.

Firefighting is the act of extinguishing destructive fires. Fire is the heat and light energy released during a Chemical reaction, in particular a combustion reaction. A firefighter fights these fires to prevent destruction of life, property and the environment. Firefighters are rescuers extensively trained primarily to put out hazardous Fires that threaten civilian populations and property to rescue people from car accidents collapsed Firefighting is a highly technical profession which requires years of training and education in order to become proficient.

Science of firefighting

Historically, physicists created a graphical representation detailing the three elements of fire (fire triangle). The fire triangle or combustion triangle is a simple model from the science of firefighting, for understanding the ingredients necessary for most Fires In recent years, one more point has been added, creating the fire tetrahedron. The fire triangle or combustion triangle is a simple model from the science of firefighting, for understanding the ingredients necessary for most Fires The four elements needed to sustain combustion are:

• fuel, oxygen, heat, and a chemical chain reaction. Combustion or burning is a complex sequence of Exothermic chemical reactions between a Fuel and an Oxidant accompanied by the production of Fuel is any material that is burned or altered in order to obtain energy Oxygen (from the Greek roots ὀξύς (oxys (acid literally "sharp" from the taste of acids and -γενής (-genēs (producer literally begetteris the In Physics, heat, symbolized by Q, is Energy transferred from one body or system to another due to a difference in Temperature

To extinguish a fire, it is necessary to remove one or more of the four components of combustion. Removing any of these will not allow combustion to continue. Firefighters work by

• Eliminating exposure of fuel that may be ignited by nearby flames or radiant heat
• Cooling the fuel below flashpoint (The temperature when a fuel is combustible)
• Containing and extinguishing the fire
• Removing debris and extinguishing all hidden fires to prevent rekindling

Firefighters' duties

Firefighters' goals are to save life, property and the environment. A fire can rapidly spread and endanger many lives; however, with modern firefighting techniques, catastrophe is usually, but not always, avoided. To prevent fires from starting a firefighter's duties include public education and conducting fire inspections. Because firefighters are often the first responders to people in critical conditions, firefighters provide basic life support as emergency medical technicians or advanced life support as licensed paramedics. Basic Life Support (BLS is a specific level of prehospital medical care provided by trained responders including Emergency medical technicians in the absence of advanced medical The Emergency Medical Technician ( EMT) exists in many countries and is a health care provider trained to provide prehospital emergency medical care Advanced Life Support (ALS- Implies that a EMT is capable of performing advanced life support skills as either an EMT-I (Intermediate or an EMT-P (Paramedic commonly referred A paramedic is a medical professional usually a member of the emergency medical service, who primarily provides Pre-hospital advanced medical and

Hazards Caused By Fire

Firefighters arrive at the scene.

A burning building casts off clouds of smoke.

The primary risk to people in a fire is smoke inhalation (breathing in smoke; most of those killed in fires die from this, not from burns). Breathing takes Oxygen in and Carbon dioxide out of the body Aerobic Organisms require oxygen to create energy via respiration, in The risks of smoke include:

• suffocation due to the fire consuming or displacing all the oxygen from the air;
• poisonous gases produced by the fire;
• aspirating heated smoke that can burn the inside of the lungs. Oxygen (from the Greek roots ὀξύς (oxys (acid literally "sharp" from the taste of acids and -γενής (-genēs (producer literally begetteris the Temperature and layers The temperature of the Earth's atmosphere varies with altitude the mathematical relationship between temperature and altitude varies among five lung is the essential Respiration organ in air-breathing Animals including most Tetrapods a few Fish and a few Snails The most primitive

As an example, plastics inside a car can generate 200,000 m³ of smoke at a rate of 20-30 m³/sec. Plastic is the general common term for a wide range of synthetic or semisynthetic organic solid materials suitable for the manufacture of industrial products . Firefighters carry self-contained breathing apparatus (SCBA) (an open-circuit positive pressure compressed air system) to prevent smoke inhalation. self contained breathing apparatus, or SCBA, sometimes referred to as a Compressed Air Breathing Apparatus (CABA or simply Breathing Apparatus (BA is

Obvious risks stem from the effects of heat. Even without contact with the flames (conduction), there are a number of comparably serious risks: burns from radiated heat, contact with a hot object, hot gases (e. Heat conduction or thermal conduction is the spontaneous transfer of thermal energy through matter from a region of higher Temperature to a region of lower A burn is a type of Injury that may be caused by Heat, cold, Electricity, Chemicals, Light, Radiation, or g. , air), steam and hot and/or toxic smoke. Smoke is the collection of airborne solid and liquid Particulates and Gases ref> ''Smoke Production and Properties'' - SFPE Handbook of Fire Protection Engineering Firefighters are equipped with personal protective equipment (PPE) that includes fire-resistant clothing (nomex or polybenzimidazole fiber (PBI)) and helmets that limit the transmission of heat towards the body. Firefighters are rescuers extensively trained primarily to put out hazardous Fires that threaten civilian populations and property to rescue people from car accidents collapsed Nomex (styled NOMEX) is a registered Trademark for flame resistant meta- Aramid material developed in the early 1960s by DuPont and first marketed Polybenzimidazole or PBI Fiber (1983 is a Synthetic fiber with an extremely high Melting point that also does not Ignite.

The heat can make pressurised gas cylinders and tanks explode, producing what is called a BLEVE (Boiling Liquid Expanding Vapor Explosion). An explosion is a sudden increase in Volume and release of Energy in an extreme manner usually with the generation of high Temperatures and the release BLEVE, pronounced /ˈblɛvi/ ("blevvy" is an Acronym for " boiling liquid expanding vapor explosion " Some chemical products such as ammonium nitrate fertilizers can also explode. The Chemical compound ammonium nitrate, the Nitrate of Ammonia with the chemical formula N[[Hydrogen H]]4 N[[Oxygen O]]3 Fertilizers ( also spelt fertiliser are chemical compounds given to Plants to promote growth they are usually applied either through the soil for uptake by plant Explosions can cause physical trauma or potentially serious blast or shrapnel injuries. Treatment of physical trauma is described here and in First aid. In Bioinformatics, B asic L ocal A lignment S earch T ool or BLAST, is an Algorithm for comparing primary Shrapnel is the term originally applied to an anti-personnel artillery shell which carried a large number of individual bullets to the target and then ejected them forwards relying

Heat causes human flesh to burn as fuel causing severe medical problems. Depending upon the heat of the fire, burns can occur in a fraction of a second. A first degree burn (on the skin surface) is extremely painful. A burn is a type of Injury that may be caused by Heat, cold, Electricity, Chemicals, Light, Radiation, or A second degree burn is a burn into the skin, and can cause shock, infections, and dehydration and if left untreated often results in death. Second degree burns compromise nerve tissue and are not painful. Third degree burns leave muscles and internal organs exposed from completely destroyed skin. If the person survives the shock and exposure to germs, medical treatment is extremely difficult.

Additional risks of firefighting encompass the following:

• vision can be obscured by the smoke: a person inside the building may not be able to see, can fall, or become disoriented and lost; becoming trapped and killed by the smoke or fire.
• the building can collapse on its occupants.

Reconnaissance and reading the fire

The first step of the operations is a reconnaissance to search for the origin of the fire (which may not be obvious for an indoor fire, especially when there are no witnesses), and spot the specific risks and the possible casualties. Any fire occurring outside may not require reconnaissance; on the other hand, a fire in a cellar or an underground car park with only a few centimeters of visibility may require a long reconnaissance to spot the seat of the fire.

The "reading" of the fire is the analysis by the firefighters of the forewarnings of a thermal accident (flashover, backdraft, smoke explosion), which is performed during the reconnaissance and the fire suppression maneuvers. For the 2007 documentary see Flashover (film. In Electric power transmission, a flashover is an unintended high voltage electric discharge over A backdraft is a situation which can occur when a Fire is starved of Oxygen; consequently combustion ceases but the fuel gases and Smoke remain at high A backdraft is a situation which can occur when a Fire is starved of Oxygen; consequently combustion ceases but the fuel gases and Smoke remain at high The main signs are:

• hot zones, which can be detected with a gloved hand, especially by touching a door before opening it;
• the presence of soot on the windows, which usually means that combustion is incomplete and thus there is a lack of air
• smoke goes in and out from the door frame, as if the fire breathes, which usually means a lack of air to support combustion;
• spraying water on the ceiling with a short pulse of a diffused spray (e. g. cone with an opening angle of 60°) to test the heat of the smoke;
  • when the temperature is moderate, the water falls down in drops with a sound of rain;
  • when the temperature is high, it vaporizes with a hiss. A cone is a three-dimensional Geometric shape that tapers smoothly from a flat round base to a point called the apex or vertex Evaporation is the process by which Molecules in a Liquid state (e

Ideally, part of reconnaissance is to consult an existing Preplan for the building. This would provide knowledge of existing structures, fire fighter hazards, and can include strategies and tactics.

Suppressing the fuel and the energy

The first method is to remove fuel for the fire by, for example, cutting off the domestic gas supply and moving combustible objects from the path of the fire. When the activation energy is still present, it is also useful to switch it off; this will not stop a fire, but will help in controlling a starting fire and will prevent a new fire from occurring.

The first action is thus to cut off the domestic gas and electricity, and switch off working machines (motors). It is also important to turn off ventilation and air conditioning, as they supply oxygen which supports combustion and can dangerously change the behaviour of the fire.

Use of water

United States Air Force Airmen from the 20th Civil Engineer Squadron Fire Protection Flight neutralize a live fire during a field training exercise at Shaw Air Force Base in South Carolina 23 May 2007. The 20th Fighter Wing ( 20 FW) is a wing of the United States Air Force and the host unit at Shaw Air Force Base South Carolina Shaw Air Force Base is the home of the United States Air Force 's 20th Fighter Wing (20 FW of the the Air Combat Command (ACC which functions as Events 1430 - Siege of Compiègne: Joan of Arc is captured by the Burgundians while leading an army to relieve Compiègne Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century.

Often, the main way to extinguish a fire is to spray with water. The water has two roles:

• in contact with the fire, it vaporizes, and this vapour displaces the oxygen (the volume of water vapour is 1,700 times greater than liquid water); leaving the fire with not enough combustive agent to continue, and it dies out. Vaporization of an element or compound is a Phase transition from the Liquid phase to Gas phase
• the vaporization of water absorbs the heat; it cools the smoke, air, walls, objects in the room, etc. Smoke is the collection of airborne solid and liquid Particulates and Gases ref> ''Smoke Production and Properties'' - SFPE Handbook of Fire Protection Engineering , that could act as further fuel, and thus prevents one of the means that fires grow, which is by "jumping" to nearby heat/fuel sources to start new fires, which then combine.

The extinction is thus a combination of "asphyxia" and cooling. The flame itself is suppressed by asphyxia, but the cooling is the most important element to master a fire in a closed area.

Water may be accessed by pressurized fire hydrant, pumped from water sources such as lakes or rivers, delivered by tanker truck, or dropped from aircraft tankers in fighting forest fires. A fire hydrant (also known colloquially as a fire plug in the United States or as a johnny pump in New York City, because the firemen of the A tank truck ( United States usage or tanker lorry ( United Kingdom usage is a Motor vehicle designed to carry liquefied loads, A wildfire, also known as a wildland fire, forest fire, brush fire, vegetation fire, grass fire, Peat fire,

Open air fire

For fires in the open, the seat of the fire is sprayed with a straight spray: the cooling effect immediately follows the "asphyxia" by vapor, and reduces the amount of water required. A straight spray is used so the water arrives massively to the seat without being vaporized before. A strong spray may also have a mechanical effect: it can disperse the combustible product and thus prevent the fire from starting again.

The fire is always fed with air, but the risk to people is limited as they can move away, except in the case of wildfires or bushfires where they can be surrounded by the flames. A wildfire, also known as a wildland fire, forest fire, brush fire, vegetation fire, grass fire, Peat fire, Ladysmith-RFSJPG|right|thumb| Ladysmith NSW RFS fire fighting tanker]]A Bushfire is a Fire that occurs in the bush (collective term for But there might be a big risk of expansion.

Spray is aimed at a surface, or object: for this reason, the strategy is sometimes called two-dimensional attack or 2D attack. In mathematics the dimension of a Space is roughly defined as the minimum number of Coordinates needed to specify every point within it

It might be necessary to protect specific items (house, gas tank) against infrared radiation, and thus to use a diffused spray between the fire and the object.

Breathing apparatus is often required as there is still the risk of breathing in smoke or poisonous gases.

Closed volume fire

Until the 1970s, fires were usually attacked while they declined, so the same strategy that was used for open air fires was effective. This article is about the Decade 1970-1979 For the Year 1970 see 1970. In recent times, fires are now attacked in their development phase as:

• firefighters arrive sooner;
• thermal insulation of houses confines the heat;
• modern materials, especially the polymers, produce a lot more heat than traditional materials (wood, plaster, stone, bricks, etc. The term thermal insulation can refer to materials used to reduce the rate of Heat transfer, or the methods and processes used to reduce heat transfer A polymer is a large Molecule ( Macromolecule) composed of repeating Structural units typically connected by Covalent Chemical bonds Wood is hard fibrous lignified structural tissue produced as secondary Xylem in the stems of Woody plants notably trees but also shrubs The term plaster can refer to plaster of Paris Lime plaster, or Cement plaster. In Geology, rock is a naturally occurring aggregate of Minerals and/or Mineraloids The Earth's outer solid layer the ‘ Lithosphere A brick is a block of Ceramic material used in Masonry construction laid using mortar. ).

Additionally, in these conditions, there is a greater risk of backdraft and of flashover. A backdraft is a situation which can occur when a Fire is starved of Oxygen; consequently combustion ceases but the fuel gases and Smoke remain at high For the 2007 documentary see Flashover (film. In Electric power transmission, a flashover is an unintended high voltage electric discharge over

Spraying of the seat of the fire directly can have unfortunate and dramatic consequences: the water pushes air in front of it, so the fire is supplied with extra oxygen before the water reaches it. This activation of the fire, and the mixing of the gases produced by the water flow, can create a flashover.

The most important issue is not the flames, but control of the fire, i. e. the cooling of the smoke that can spread and start distant fires, and that endanger the lives of people, including firefighters. The volume must be cooled before the seat is treated. This strategy originally of Swedish (Mats Rosander & Krister Giselsson) origin, was further adapted by London Fire Officer Paul Grimwood following a decade of operational use in London's busy west-end district between 1984-94 (www. firetactics. com) and termed three-dimensional attack, or 3D attack. In mathematics the dimension of a Space is roughly defined as the minimum number of Coordinates needed to specify every point within it

Use of a diffused spray was first proposed by Chief Lloyd Layman of Parkersburg, West Virginia Fire Department, at the Fire Department Instructor's Conference (FDIC) in 1950 held in Memphis, Tennessee, U. Memphis is a City in the southwest corner of Tennessee, and the County seat of Shelby County. S. A.

Using Grimwood's modified '3D attack strategy' the ceiling is first sprayed with short pulses of a diffused spray:

• it cools the smoke, thus the smoke is less likely to start a fire when it moves away;
• the pressure of the gas drops when it cools (law of ideal gases), thus it also reduces the mobility of the smoke and avoids a "backfire" of water vapour;
• it creates an inert "water vapour sky" which prevents roll-over (rolls of flames on the ceiling created by the burning of hot gases). These four properties that constitute an ideal gas can be easily remembered by the acronym RIPE which stands for - R andom Motion (molecules are in constant random motion

Only short pulses of water must be sprayed, otherwise the spraying modifies the equilibrium, and the gases mix instead of remaining stratified: the hot gases (initially at the ceiling) move around the room and the temperature rises at the ground, which is dangerous for firefighters. An alternative is to cool all the atmosphere by spraying the whole atmosphere as if drawing letters in the air ("pencilling").

The modern methods for an urban fire dictate the use of a massive initial water flow, e. g. 500 L/min for each fire hose. The aim is to absorb as much heat as possible at the beginning to stop the expansion of the sinister, and to reduce the smoke. When the flow is too small, the cooling is not sufficient, and the steam that is produced can burn firefighters (the drop of pressure is too small and the vapor is pushed back). Although it may seem paradoxical, the use of a strong flow with an efficient fire hose and an efficient strategy (diffused sprayed, small droplets) requires a smaller amount of water: once the temperature is lowered, only a limited amount of water is necessary to suppress the fire seat with a straight spray. For a living room of 50 m² (60 square yards), the required amount of water is estimated as 60 L (15 gallons).

French fire-fighters used an alternative method in the 1970s: they sprayed water on the hot walls to create a water vapour atmosphere and asphyxiate the fire. This method is no longer used because it was risky: the pressure created pushed the hot gases and vapour towards the firefighters, causing severe burns, and pushed the hot gases into other rooms where they could start a new fire.

Asphyxiating a fire

In some cases, the use of water is undesirable:

• some chemical products react with water and produce poisonous gases, or even burn in contact with water (e. A chemical reaction is a process that always results in the interconversion of Chemical substances The substance or substances initially involved in a chemical reaction are called g. sodium);
• some products float on water, e. Sodium (ˈsoʊdiəm is an element which has the symbol Na( Latin natrium, from Arabic natrun) atomic number 11 atomic mass 22 g. hydrocarbon (gasoline, oil, alcohol, etc. In Organic chemistry, a hydrocarbon is an Organic compound consisting entirely of Hydrogen and Carbon. Petroleum ( L petroleum, from Greek πετρέλαιον, lit In Chemistry, an alcohol is any Organic compound in which a Hydroxyl group ( - O[[hydrogen H]]) is bound to a Carbon ); a burning layer can then spread and extend;
• in case of a pressurised gas tank, it is necessary to avoid heat shocks that may damage the tank: the resulting decompression may produce a BLEVE. BLEVE, pronounced /ˈblɛvi/ ("blevvy" is an Acronym for " boiling liquid expanding vapor explosion "

It is then necessary to asphyxiate the fire. This can be done in two ways:

• some chemical products react with the fuel and stop the combustion;
• a layer of water-based fire retardant foam is projected on the product by the fire hose, to keep the oxygen in air separated from the fuel. Fire Retardant Foam, or fire suppression foam, is a Foam used for fire suppression.

Tactical ventilation or isolation of the fire

One of the main risks of a fire is the smoke: it carries heat and poisonous gases, and obscures vision. Smoke is the collection of airborne solid and liquid Particulates and Gases ref> ''Smoke Production and Properties'' - SFPE Handbook of Fire Protection Engineering In the case of a fire in a closed location (building), two different strategies may be used: isolation of the fire, or positive pressure ventilation.

Paul Grimwood introduced the concept of tactical ventilation in the 1980s to encourage a more well thought out approach to this aspect of firefighting. Following work with Warrington Fire Research Consultants (FRDG 6/94) his terminology and concepts were adopted officially by the UK fire service and are now referred to throughout revised Home Office training manuals (1996-97).

Paul Grimwood's original definition of his 1991 unified strategy stated that . . . .

'tactical ventilation is either the venting, or containment (isolation) actions by on-scene firefighters, used to take control from the outset of a fire's burning regime, in an effort to gain tactical advantage during interior structural firefighting operations'.

Positive pressure ventilation (PPV) consists of using a fan to create excess pressure in a part of the building; this pressure will push the smoke and the heat away, and thus secure the rescue and fire fighting operations. In positive pressure ventilation, a Mechanical ventilator forces air into the lungs to assist breathing in patients with temporary or chronic respiratory difficulty A mechanical fan is an electrically powered device used to produce an airflow for the purpose of creature comfort (particularly in the heat ventilation, exhaust It is necessary to have an exit for the smoke, to know the building very well to predict where the smoke will go, and to ensure that the doors remain open by wedging or propping them. The main risk of this method is that it may activate the fire, or even create a flashover, e. For the 2007 documentary see Flashover (film. In Electric power transmission, a flashover is an unintended high voltage electric discharge over g. if the smoke and the heat accumulate in a dead end.

Categorizing fires

Main article: Multiple-alarm fire

Fires are sometimes categorized as "one alarm", "two alarm", "three alarm" (or higher) fires. Fires are sometimes categorized as one-alarm, two-alarm, three-alarm fires, or higher There is no standard definition for what this means quantifiably, though it always refers to the level response by the local authorities. In some cities, the numeric rating refers to the number of fire stations that have been summoned to the fire. In others, the number counts the number of "dispatches" for additional personnel and equipment. [1][2]

Appendix : Calculation of the amount of water required to suppress a fire in a closed volume

In the case of a closed volume, it is easy to compute the amount of water needed. The oxygen (O₂) in air (21%) is necessary for combustion. Oxygen (from the Greek roots ὀξύς (oxys (acid literally "sharp" from the taste of acids and -γενής (-genēs (producer literally begetteris the Combustion or burning is a complex sequence of Exothermic chemical reactions between a Fuel and an Oxidant accompanied by the production of Whatever the amount of fuel available (wood, paper, cloth), combustion will stop when the air becomes "thin", i. e. when it contains less than 15% oxygen. If additional air cannot enter, we can calculate:

• The amount of water required to make the atmosphere inert, i. Temperature and layers The temperature of the Earth's atmosphere varies with altitude the mathematical relationship between temperature and altitude varies among five e. to prevent the pyrolysis gases to burn; this is the "volume computation";
• The amount of water required to cool the smoke, the atmosphere; this is the "thermal computation". Pyrolysis is the Chemical decomposition of organic materials by heating in the absence of Oxygen or any other reagents except possibly Steam

These computations are only valid when considering a diffused spray which penetrates the entire volume; this is not possible in the case of a high ceiling: the spray is short and does not reach the upper layers of air. Consequently the computations are not valid for large volumes such as barns or warehouses: a warehouse of 1,000 m² (1,200 square yards) and 10 m high (33 ft) represents 10,000 m³. In practice, such large volumes are unlikely to be airtight anyway.

Volume computation

Fire needs air; if water vapour pushes all the air away, the fuel can no longer burn. But the replacement of all the air by water vapour is harmful for firefighters and other people still in the building: the water vapour can carry much more heat than air at the same temperature (one can be burnt by water vapour at 100 °C (212 °F) above a boiling saucepan, whereas it is possible to put an arm in an oven—without touching the metal!—at 270 °C (520 °F) without damage). This amount of water is thus an upper limit which should not actually be reached.

The optimal, and minimum, amount of water to use is the amount required to dilute the air to 15% oxygen: below this concentration, the fire cannot burn.

The amount used should be between the optimal value and the upper limit. Any additional water would just run on the floor and cause water damage without contributing to fire suppression.

Let:

• V_r be the volume of the room,
• V_v be the volume of vapour required,
• V_w be the volume of liquid water to create the V_v volume of vapour,

then for an air at 500 °C (773 K, 932 °F, best case concerning the volume, probable case at the beginning of the operation), we have^[3]

and for a temperature of 100 °C (373 K, 212 °F, worst case concerning the volume, probable case when the fire is suppressed and the temperature is lowered):^[4]

For the maximum volume, we have:

V_v = V_r

considering a temperature of 100 °C. To compute the optimal volume (dilution of oxygen from 21 to 15%), we have^[5]

for a temperature of 500 °C. The table below show some results, for rooms with a height of 2. 70 m (8 ft 10 in).

Note that the formulas give the results in cubic meters; which are multiplied by 1,000 to convert to liters.

Of course, a room is never really closed, gases can go in (fresh air) and out (hot gases and water vapour) so the computations will not be exact.

Notes

^  indeed, the mass of one mole of water is 18 g, a liter (0. The mole (symbol mol) is a unit of Amount of substance: it is an SI base unit, and almost the only unit to be used to measure this 001 m³) represents one kilogram i. e. 55. 6 moles, and at 500 °C (773 K), 55. 6 moles of an ideal gas at atmospheric pressure represents a volume of 3. These four properties that constitute an ideal gas can be easily remembered by the acronym RIPE which stands for - R andom Motion (molecules are in constant random motion 57 m³.

^  same as above with a temperature of 100 °C (373 K), one liter of liquid water produces 1. 723 m³ of vapour

^  we consider that only V_r - V_v of the original room atmosphere remains (V_v has been replaced by water vapour). This atmosphere contains less than 21% of oxygen (some was used by the fire), so the remaining amount of oxygen represents less than 0,21·(V_r-V_v). The concentration of oxygen is thus less than 0,21·(V_r-V_v)/V_r, and we want this fraction to be 0. 15 (15%).

See also

Main list: List of basic fire fighting topics

Firefighting Training