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Firefighter in silhouette surrounded by flames

Fire fighting

by Chris Woodford. Last updated: September 19, 2014.

Fire gobbles its way through trees and buildings like a hungry animal—and in a sense that's exactly what it is: a living, breathing animal. Fire is a chemical reaction that feeds on fuel and oxygen. Give it plenty of both and it'll keep on burning indefinitely. Thank goodness, then, for firefighters, those brave men and women who set themselves the job of stopping fire in its tracks. Fire fighting is one of the toughest jobs there is and it calls for some equally tough equipment. Let's take a closer look at how to tackle those flames!

Photo: Firefighters wear all-over aluminum suits to tackle the worst blazes; suits made of fireproof Nomex® and Kevlar® are used for less severe fires. Photo by Liam Kennedy courtesy of US Navy.

Extraordinary people

Firefighters wearing breathing apparatus.

Firefighting is a dangerous and demanding job that calls for total teamwork: it can take several people just to hold a powerful fire hose working at full pressure. Men and women make equally good firefighters, but must be no younger than 21 and usually retire at 55. Firefighters have to pass strict medicals and physicals and also take written theory tests. They're constantly trained in new firefighting techniques. Firefighting is a stressful job with long periods of waiting. Often firefighters pass the time at the station by playing games like table football.

Photo: Fire has a voracious appetite for oxygen and, when it burns materials such as plastics, it can give off highly toxic chemicals. That's why firefighters often have to wear breathing apparatus. It's worth remembering that firefighters often have to work in darkness and thick smoke, which makes their job even more difficult and dangerous. Photo by courtesy of US Department of Energy (DOE).

Amazing equipment

What turns an ordinary man or woman into a firefighter? Apart from heroic bravery and determination, it's the clothes they wear and the equipment they use. Firefighters wear jackets made from synthetic materials such as Nomex® and Kevlar®. They are fireproof, insulate against heat, and resist many different chemicals. Helmets, made from carbon-based composite materials, are hard-wearing and shockproof. A special mixture of glass and plastic protects visors against high temperatures.

Closeup of the pump inside a fire truck

A historic fire engine cart from 1880

Fire trucks

A fire truck (sometimes called a fire engine) has to carry firefighters and equipment to burning buildings. It also has to pump large volumes of water, sometimes over long distances, to extinguish the flames. Typical fire trucks carry about 1900 liters (500 gallons) of water and draw bigger supplies from hydrants (like giant faucets positioned on streets—described more fully below) near the scene. They also carry assorted portable extinguishers for tackling smaller or more unusual fires.

Photo: Left: A closeup of the pump inside an airport fire truck. You can connect several different hoses at once and each one has separate controls. There are stopcocks to turn the water on and off and dials to tell you the water pressure. Note the thick, insulated rubber boots the firefighter is wearing to to protect against heat, cold, and resist oils, chemicals, and salt. They also have steel toecaps to protect against impacts. Photo by Rebecca Layman courtesy of US Air Force and Defense Imagery.

Photo: Right: Fire trucks as they used to be. This is a horse-drawn fire cart dating from 1880. Note the primitive, bucket-style fire extinguisher pump on the left. It's currently an exhibit at the National Trust's Lanhydrock country house in Cornwall, England.

What's inside a fire truck?

Photo by Jeanette Copeland courtesy of RAF Mildenhall and Defense Imagery.

Labelled photo of a fire engine truck showing some of the equipment inside

Miscellaneous equipment carried inside a fire truck

  1. Large trucks carry up to 300 m (1000 ft) of hose.
  2. Multiple hoses allow several firefighters to work at once. Hoses are often different colors to prevent confusion in the chaos of a major fire. After use, the hoses are hung up to dry from tall towers back at the station to stop them getting damaged.
  3. Different hose nozzles can make hard jets, soft spray, or fine mist.
  4. Axes, cutters, rams, and blades are stored in secure cabinets on the truck to help firefighters gain entry to buildings. (See also inset photo.)
  5. Tank of foam can be added to water to tackle chemical fires.
  6. Shuttered doors conceal main pumping unit controls and more tools.
  7. (Not shown) Several ladders carried on roof, each up to 40 ft (12 m) long.
  8. Aluminum fire suit and breathing apparatus.
  9. Chemical-proof rubber boots.
  10. Toughened, flameproof glass and plastic helmet visor.

Photo: Right: Some of the cutting equipment, axes, and other tools carried onboard a fire truck. Photo by Tabitha Kuykendall courtesy of US Air Force and Defense Imagery.

Rescue Vehicles

Firefighters tackle a burning building with hoses and extended turntable ladders.

Firefighters don't just put out fires. Most fire departments have dedicated rescue trucks designed for tackling automobile accidents, which carry hydraulic jacks and airbags for lifting overturned vehicles, a punch for breaking windscreens, and high-temperature gas torches that can cut people free from crashed cars. One new tool is a steering-wheel cover to stop a car's airbag from inflating and injuring firefighters as they work.

Photo: Firefighters from the Washington, DC Fire Department tackle a burning building with hoses and a "hook and ladder" truck (a fire truck equipped with huge onboard ladders and other rescue equipment). One way of using a truck like this is to attach a fire hose to the top of an extended ladder. The hose can then be operated safely by firefighters standing at the bottom, who pull on a cable or swivel the turntable ladder to direct the water. In this case, it's safer because the firefighters don't have to stand so near the flames and heat from the burning roof. Photo by Dave Hyatt courtesy of US Air Force and Defense Imagery.

Fire ambulances

Ambulances are like miniature hospitals inside, allowing paramedics to give rapid treatment to casualties at the scene. firefighters tackle three quarters of all medical emergencies. Fire ambulances carry equipment to deal with common fire injuries. Respirators help people breathe normally after inhaling smoke, while defibrillators are portable electric-shock machines that can often restart someone's heart if it stops beating properly. Special bandages and hydrocolloidal dressings provide treatment for burns. There are also masks, gloves, and overalls to isolate people contaminated by chemical spills.

Fire hydrants

Fire hydrant spraying water

A fire hydrant is really nothing more than a large outdoor faucet (or tap, as it's called in some countries) designed to supply huge amounts of water to fire trucks, very quickly, whenever and wherever fires break out. A typical hydrant has up to four nozzles, one on each side, to which up to four sturdy fire-hoses can be tightly screwed. To prevent tampering, the nozzles are held shut by pentagonal (five-sided) nuts that can be opened only with a special wrench. At the top, there is a similar nut and sometimes a wheel directly beneath it. Turning the nut and the wheel unscrews a valve inside the hydrant. This allows water to flow up from an underground pipe and out through whichever nozzles have been opened. Unlike an ordinary faucet, a fire hydrant is designed to operate either completely on or completely off.

Photo: Fire hydrants are like faucets that stop up water supplies under high pressure. That's why the water really sprays out when they're opened. Photo by Stephen Schester courtesy of US Air Force and Defense Imagery.

It can take an enormous amount of water, sprayed for several hours, to put out a large urban fire—and time is always of the essence for firefighters. Ordinary faucets could not possibly supply enough water to do this job quickly enough: they are designed to supply small amounts of water over short distances and at quite low pressures. In this respect, fire hydrants are very different. Where a domestic faucet can provide just enough water to power a garden hose around 2 cm (0.75 inch) thick, a fire hydrant can fill a hose up to eight times thicker. Even the most powerful domestic faucet can deliver only a few gallons of water every minute. But a typical fire hydrant can supply water up to a thousand times faster. The water from a fire hydrant is at several times higher pressure than the water in your faucets at home: it can come out of the hydrant at 80 psi or more (roughly six times the pressure of the air we breathe).

Tanked up

Brown fire hydrant being opened up, with its main parts labeled

Fire hydrants are the most visible part of our emergency water systems—but they are not the only part. The water that supplies hydrants comes from large tanks or reservoirs usually located on hilltops. Each of these is designed to supply enough water to operate fire hydrants for hours at a time. The tanks are connected to the hydrants by a system of pipes laid out in a grid pattern. This means the water can travel from any tank to any hydrant via several different routes, so a hydrant will continue to work even if one of the pipes springs a leak. When a firefighter opens the valve on a hydrant, the force of gravity makes water run downhill from the tank, through the grid of pipes, to whichever hydrant nozzles are open. The higher the tank is located, the more speed and pressure the water will build up, the quicker it will be delivered—and the faster the fire will be put out.

Parts of a fire hydrant

Fire hydrants are just fire hydrants, right? Wrong! Here are some of the little details you might not have noticed:

  1. Operating nut on top of hydrant turns main water valve on or off
  2. Hose is attached to one of the four sides of the hydrant. A clapper valve just inside the hydrant stops water from flowing backwards. Water can flow out of the hydrant into the hose but not in the opposite direction.
  3. Raised metal body of hydrant ensures it operates at the same height as a fire truck's water inlet. This helps to stop fire hoses from kinking.
  4. Breakable bolts on base are designed to snap if a vehicle strikes the hydrant.
  5. Safety chain stops nozzle caps from getting lost when hydrant is in operation.
  6. Outlet nozzles have screw threads inside to which fire hoses can be securely attached. Remember that the water is at very high pressure and the hoses will come off if they're not screwed on tight!

Photo: Key parts of a fire hydrant. Photo by Perry Aston taken at Joint Base Andrews, Md, and published courtesy of US Air Force and Defense Imagery.

The science of fighting fires

Understand the science behind a fire and you're halfway to putting it out. Fire is a chemical reaction between oxygen (from the air) and fuel (something that will burn to release energy), but it doesn't happen all by itself: you need to add some energy (in the form of heat) to kick it off.

Break the fire triangle!

The fire triangle

Another way of looking at it is to say that most everyday fires need three things to be present: heat, oxygen, and fuel. As long as there's plenty of all three, a fire can go on burning indefinitely. But take away one of them and the fire will go out. This idea is called breaking the fire triangle and it's the basic theory of fighting most fires. You can put out a fire by cooling it down (removing the heat), cutting off the air supply (reducing the oxygen that can get to it), or getting rid of the fuel (the usual way to do this is to remove combustible materials from near a fire and stopping it from spreading with things like fire breaks).

Artwork: Breaking the fire triangle: removing one or more of heat, air (oxygen), or fuel is the way to tackle most everyday fires.

The fire triangle at work

Here are some examples of how different fire-fighting methods work by breaking one or more sides of the fire triangle:

Fire-fighting at home

Typical fire blanket

So far, we've been looking at how firefighters tackle big fires using things like giant fire trucks hooked up to hydrants. Most big fires (especially most household fires) start out as little fires. If someone had tackled them straightaway, the minute they started, they might have saved a great deal of damage. Now most of the time, it's best to leave firefighting to the professionals. But there are times when it's okay to tackle small fires yourself, as long as you're certain that it's safe to do so. If you're going to fight a fire, you need to learn how to do it correctly beforehand. Do it the wrong way and you could put yourself at great danger and make things worse.

Fighting stove-top fires is a good example. If you're foolish enough to leave cooking pans unattended on your stove, you can cause a serious, life-threatening fire. But you can make matters far worse by tackling a fire like this the wrong way. One thing you must never do is put water on a hot oil ("chip-pan") fire, because that can produce a massive fireball. A very good way to tackle chip pan fires is to use a fire blanket.

Photo: A basic fire blanket removed from its protective plastic case and ready to use. Note the black tapes at the bottom that you pull on to release it. Get one of these and hang it up in your kitchen, away from the stove, where it's ready if you need it.

How not to tackle a chip-pan fire

Before you can tackle a fire the right way, it helps to know how people often tackle it the wrong way.

Here's the golden rule. Never, ever throw water onto a hot oil (chip-pan) fire. What happens is that the water will boil and turn to steam extremely quickly, throwing a huge spray of burning oil droplets high into the air. Because the oil is burning, spreading it out like this gives it rapid access to much more oxygen—and this is what causes a fireball. If you want to see how deadly this can be, watch this public service fire safety video on YouTube made by the British Fire Brigade. It shows you how to tackle a kitchen fire safely and calmly.

Never use a fire extinguisher on a chip-pan fire, for the same reason. A water extinguisher will have the same effect as throwing on water, a carbon dioxide extinguisher will blast and spread the hot burning oil, and a powder extinguisher can cause an explosion. That's why a fire blanket is generally the best thing to use.

What is a fire blanket?

Fire blankets are made from thick wool treated with a flameproof coating, fiberglass, or flameproof synthetic materials such as Nomex® and Kevlar®. They're not just for chip-pan fires: you can use them to help tackle chemical fires wherever it's safe to do so. You can also wrap them around someone whose clothes have caught fire, or you can wrap them around your body to help you escape from flames.

Typical fire blanket in closeup, showing the woven fiberglass fibers.

Photo: You can clearly see the woven fiberglass in this blanket. It looks and feels a bit like a sturdy, flameproof tablecloth.

How does a fire blanket work?

If a fire breaks out in your home, generally the best thing to do is get out as quickly as possible without panicking, close the doors behind you, and call the fire service (fire brigade). It may be safe for you to tackle a small fire yourself, in the early stages, with a fire extinguisher or a fire blanket, but if you have any doubts at all, leave it and get yourself and others to safety: you can replace anything except your own life. If you have a hot oil (chip pan) fire in your kitchen, the most effective way to tackle it is to place a fire blanket on top of it to cut off the oxygen supply. If you have no fire blanket, soak a tea towel in water, wring it out, then place that completely over the pan. Both of these methods break the fire triangle by removing air.

How to use a fire blanket

If you're not sure how to use a fire blanket, be sure to read the instructions on the container when you buy one so you know how to do it properly should the need ever arise. The basic idea is:

  1. Turn off the heat if it's safe to do so.
  2. Don't move the pan.
  3. Go to the fire blanket. Pull on the tapes to release the blanket from its container.
  4. Wrap the blanket around your hands before you go near the fire so you don't burn yourself in the process.
  5. Put the blanket over the container to smother the flames.
  6. Leave the pan to cool completely. If necessary, leave it a couple of hours to be on the safe side.
  7. Now leave the fire alone, get out, and if necessary call the fire service (fire brigade). Do not go back to the fire and do not uncover it again until it is completely cool.

If you have the slightest doubt about whether you can tackle a fire safely without risk to yourself or others, just leave it alone, alert any other people nearby, get yourselves well away, and call the fire service immediately.

And remember: if in doubt, just get out! Leave the fire and get yourself to safety.

Why doesn't a fire blanket burn?

Fire, as we saw up above, is a chemical reaction between a fuel and oxygen that's kick-started by heat energy. Not everything burns when you apply heat. Apply heat to a block of ice and it doesn't burst into flames: instead of a taking part in a chemical reaction, it undergoes a physical transformation: it changes from its solid state (ice) to a liquid (water) or gas (steam).

Fireproof materials (such as those used in fire blankets) are chosen for the job because they don't burn at the kinds of temperatures we see in everyday fires; apply heat and they do eventually change form—but in other, safer ways. Take Nomex®, for example. It's a nylon-like plastic, based on carbon, that simply doesn't burn. Apply enough heat to it and you'll char it—reduce it mostly to carbon—but it doesn't actually burn in the same way as other carbon-rich materials (such as wood) and it doesn't melt or drip.

Always replace a fire blanket after you've used it on a fire because it's most likely coated or impregnated with oil, food, or other flammable materials. That means if you try to use it a second time, it will most likely burn!

More ways to fight fires at home

Fire blankets are great for kitchen fires, but they're not always appropriate or effective for tackling other kinds of fire at home. If you have a home workshop, it makes sense to have one or more fire extinguishers. If you're often away from home, fire sprinklers can be a good investment. And every home should have at least one smoke detector to safeguard the people inside, particularly from fires that break out at night.

Fire facts and statistics

Bar chart showing fire deaths in five typical countries per 100,000 people. Pie chart showing sources of typical fires.

Charts: Top: The USA has more fire deaths per 100,000 people than comparable European countries. Bottom: Three quarters of all fires involve either buildings, wild fires, or vehicles.

World fire statistics

United States

UK

France

Germany

Source: World Fire Statistics 2004.

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Text copyright © Chris Woodford 2008, 2012. All rights reserved. Full copyright notice and terms of use.

Nomex and Kevlar are trademarks or registered trademarks of E. I. du Pont de Nemours and Company.

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Woodford, Chris. (2008) Firefighting. Retrieved from http://www.explainthatstuff.com/firefighting.html. [Accessed (Insert date here)]

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