All fires require oxygen, fuel and heat. These three elements brought together in the right combination will produce fire and are known collectively as the "fire triangle."
To better understand how fires work, modern fire experts have expanded the "fire triangle" to include a fourth element. The fourth element is the complex molecular chain reaction between the fuel and the oxygen that keep a fire
burning once it has started. The resulting diagram is called the "fire tetrahedron."
Oxygen is all around us and almost any material can become fuel for a fire: clothing, furniture, wood, paper, plastics, flammable gases and flammable liquids such as gasoline. All it takes is a human act or oversight, a mechanical
or electrical malfunction, or some natural event such as lightning to bring oxygen fuel and heat together to create a fire.
Fires can be extinguished by removing just one of the elements of the "fire tetrahedron." Removing the fuel, cutting off the supply of oxygen, reducing the fuel's temperature, or disrupting the chemical chain reaction will
extinguish the fire.
How Fires Kill
Severe burns are only one cause of fire deaths. Only about one-fourth of home fire victims die from burns. The majority die from inhaling poisonous gases found in the smoke or from lack of oxygen.
Once a fire starts, its effects on the atmosphere can quickly make your home a deadly place. Fire consumes oxygen. Normally, the air we breathe is 21 percent oxygen. During a fire, that level drops rapidly. If it drops below 17
percent, people breathing the air will have difficulty thinking clearly and controlling their muscles. They may become irrational and uncoordinated, making escape more difficult. When the oxygen in the air drops into the 10 to 12
percent range, four to six minutes without oxygen will cause brain death.
Smoke inhalation is the leading cause of death in fires. Fires produce smoke that contains poisonous gases that can kill you long before the flames reach you. The majority of fatal home fires happen at night when people are asleep.
A sleeping person who inhales poisonous gases may never wake up or may pass out as soon as he or she stands up to escape.
There are four common deadly gases associated with fires in the home. These gases are carbon monoxide, hydrogen cyanide, hydrogen chloride and carbon dioxide.
- Carbon monoxide is a poisonous gas that displaces oxygen in the blood. It is the most abundant of all fire gases and is produced by all fires.
- Hydrogen cyanide is also a deadly poison produced by burning wool, silk, nylon and some plastics. Common elements in blankets, upholstered furniture, curtains and clothing.
- Hydrogen chloride irritates your throat and eyes, increasing your breathing rate and making it difficult to see to escape. The increased breathing rate causes you to inhale all the toxic byproducts of fire faster.
- Carbon dioxide in the air causes you to breathe faster, increasing your intake of the other poisonous gases released by fire.
Smoke also contains particles of burned fuel that obscure light. The particles decrease visibility and irritate your eyes causing a further decrease in visibility.
Fires produce intense heat, sometimes in excess of 1100 degrees. Intense heat will burn exposed skin and damage your body through heat stress. Breathing superheated air can also cause rapid and severe lung damage. None of the human
body’s natural temperature regulating mechanisms such as breathing and perspiring can keep pace with the heat and exposure to such extreme temperatures can cause unconsciousness in seconds.
Surviving a Home Fire
To survive a home fire, you must be prepared and respond quickly. You need to have fire protection systems such as smoke alarms and automatic fire sprinkler systems that can detect and or control a fire quickly. You need to know
what to do. In a fire emergency, seconds count.
Home Fire Drills
It's essential that every household have a plan for escaping a fire and practice it by holding fire drills at least twice a year. Many people make poor decisions when fire breaks out. They may be affected by smoke, disoriented by
being awakened abruptly and frightened. The more you practice your escape plan, the more likely you and your family are to make proper decisions and escape safely.
Draw a floor plan of your home
Use a large sheet of paper or a grid sheet to draw a floor plan of your home. Be thorough. Include all windows, doors, outdoor features and possible obstacles in your drawing. Indicate primary and alternate escape routes from each
room. Know at least two ways out of each room and show them on your floor plan. Fire is unpredictable. It can block any exit path.
In a two-story home, plan safe escape routes through second-story windows. Can you climb out onto a roof or balcony? If not, purchase a non-combustible escape ladder that is tested and labeled by an independent testing laboratory.
Post your floor plan with the fire department's emergency number on a bulletin board near your phone where babysitters and visitors can see them. Revise your plan as circumstances change in your household. Make sure everyone
including young children, older adults and people with disabilities are included.
Learn your escape routes and keep them clear
Assess each escape route realistically to be sure it can be used in an emergency. Walk through the primary and alternative escape routes, making sure that all exits are accessible to all members of your household. Can everyone open
all windows? Are stairs and hallways clutter free? Be sure that balconies, roofs and escape ladders included in your plan can support the weight of the heaviest member of the household.
Be sure that windows in your home are not painted shut or blocked and do not have a screwed-on screen or storm window that can't be opened from the inside. Windows or doors protected by security bars should have quick release
mechanisms that everyone in the family can operate. Locked and barred doors should open easily from the inside and every member of your household should be able to open them.
Teach your children what to do in a fire
Have each child in your household memorize the fire department's phone number and have them practice giving your address. Make sure they understand that they should escape first and know which neighbors to go to in the event of a
fire emergency. Teach your children, even very young children, that they must escape from a fire and never hide in places they might think are safe, such as a closet, bedroom, or under a bed.
Don't wait. Parents should not expect children to stay in their rooms until someone comes to help. In a fire, parents may be blocked from their children's bedrooms by smoke or flame. Each child should know how to escape a fire and
be taught to do so as soon as her or she smells smoke or hears the sound of a smoke alarm.
Hold an exit drill every six months
A recent survey revealed that while many people have home escape plans, only one in four have plans they have practiced. Practice your escape plan at least twice a year. Try an unannounced drill to make the experience as realistic
as possible. Appoint a monitor to begin the drill by pushing the test button on a smoke alarm and yelling, "Fire drill, everybody out!"
Some studies have shown that some children may not awaken to the sound of the smoke alarm. Know what your child will do before a fire occurs. For more information on this issue, smoke alarms and escape planning visit
- Make sure everyone in your home knows the sound of your smoke alarm.
- In a real fire, you must be prepared to move quickly, carefully and calmly. Don't let your exit drill become a race, make sure everyone knows exactly what to do. Don't run.
- Vary your drills be pretending some escape routes are blocked.
- Since the majority of fatal home fires start when people are asleep, practice your escape plan by having each member of your household wait in his or her sleeping area for the monitor to sound the alarm.
- Start by coaching your children but remember that your goal is to teach them to escape without your help.