Circle time discussions on fire fighting.





Firefighting is the act of extinguishing fires. A firefighter suppresses and extinguishes fires to prevent loss of life, and/or destruction of property and the environment. Firefighters may provide many other valuable services to the community they serve, such as emergency medical services. Firefighting is a highly technical skill that requires professionals who have spent years training in both general firefighting techniques and specialized areas of expertise. Some of the specialized area of fire and rescue operations include Aircraft/airport rescue; Wild land fire suppression; and Search and rescue
One of the major hazards associated with firefighting operations is the toxic environment created by combusting materials. The four major hazards associated with these situations are

1)      smoke

2)      The oxygen deficient atmosphere

3)       elevated temperatures and

4)       Toxic atmospheres.

 Additional risks of fire include falls and structural collapse. To combat some of these risks, firefighters carry self-contained breathing apparatus. (SCBA; an open-circuit positive pressure compressed air system) to prevent smoke inhalation. These are not oxygen tanks; they carry compressed air. SCBA usually hold 30 to 45 minutes of air, depending upon the size of the tank and the rate of consumption during strenuous activities.

Obvious risks are associated with the immense heat. Even without direct contact with the flames (direct flame impingement), conductive heat can create serious burns from a great distance. There are a number of comparably serious heat-related risks: burn from radiated heat, contact with a hot object, hot gases (e.g., air), steam and hot and/or toxic smoke. Firefighters are equipped with personal protective equipment (PPE) that includes fire-resistant clothing and helmets that limit the transmission of heat towards the body. No PPE, however, can completely protect the user from the effects of all fire conditions.

Heat can make flammable liquid tanks violently explode, producing what is called a BLEVE (boiling liquid expanding vapor explosion). Some chemical products can also explode. Explosions can cause physical trauma or potentially serious injuries.

Heat causes human flesh to burn as fuel, or the water within to boil, causing potentially severe medical problems. Depending upon the heat of the fire, burns can occur in a fraction of a second.

Additional risks of fire include the following:

• smoke can obscure vision, potentially causing a fall, disorientation, or becoming trapped in the fire;
• structural collapse.

Three hours of fighting a fire stiffens arteries and impairs cardiac function in firefighters, according to a new study by Bo Fernhall, a professor in the department of kinesiology and community health in the College of Applied Health Sciences, and Gavin Horn, director of research at the Illinois Fire Service Institute. The conditions (observed in healthy male firefighters) are "also apparently found in weightlifters and endurance athletes...

Classes of fire

Name of Class	Type of Fire	Fuel Involved
Class A Fires	Freely Burning Materials	Wood, Paper, Straw, Textiles, Coal etc.
Class B Fires	Flammable Liquids	Petrol, Diesel, Oils, Paraffin etc
Class C Fires	Flammable Gases	Methane, Propane, Hydrogen, Natural Gas etc.
Class D Fires	Flammable Metals	Magnesium, Aluminum, Lithium etc
Class F Fires	Combustible Cooking Media	Cooking Oil, Fats, Grease
Electrical fire	Electrical Appliances	Computers, Stereos, Fuse boxes

Science of extinguishment

The first step of a firefighting operation is a reconnaissance to search for the origin of the fire and identification of the specific risks and any possible casualties.

Fire elements There are four elements needed to start and sustain a fire and/or flame. These elements are classified in the “fire tetrahedron” and are:

1. Reducing agent (fuel)
2. Heat
3. Oxidizing agent (oxygen)
4. Chemical Reaction

The reducing agent, or fuel, is the substance or material that is being oxidized or burned in the combustion process. The most common fuels contain carbon along with combinations of hydrogen and oxygen. Heat is the energy component of the fire tetrahedron. When heat comes into contact with a fuel, it provides the energy necessary for ignition, causes the continuous production and ignition of fuel vapors or gases so that the combustion reaction can continue, and causes the vaporization of solid and liquid fuels. The self-sustained chemical chain reaction is a complex reaction that requires a fuel, an oxidizer, and heat energy to come together in a very specific way. An oxidizing agent is a material or substance that when the proper conditions exist will release gases, including oxygen. This is crucial to the sustainment of a flame or fire.

A fire can be extinguished by taking away any of the four components of the tetrahedron. One method to extinguish a fire is to use water. The first way that water extinguishes a fire is by cooling, which removes heat from the fire. This is possible through water’s ability to absorb massive amounts of heat by converting water to water vapor. Without heat, the fuel cannot keep the oxidizer from reducing the fuel to sustain the fire. The second way water extinguishes a fire is by smothering the fire. When water is heated to its boiling point, it converts to water vapor. When this conversion takes place, it dilutes the oxygen in the air with water vapor, thus removing one of the elements that the fire requires to burn. This can also be done with foam.

Another way to extinguish a fire is fuel removal. This can be accomplished by stopping the flow of liquid or gaseous fuel or by removing solid fuel in the path of a fire. Another way to accomplish this is to allow the fire to burn until all the fuel is consumed, at which point the fire will self-extinguish.

One final extinguishing method is chemical flame inhibition. This can be accomplished through dry chemical and halogenated agents. These agents interrupt the chemical chain reaction and stop flaming. This method is effective on gas and liquid fuels because they must flame to burn.

HOW TO USE A FIRE EXTINGUISHER

Simple acronym P.A.S.S. to help you use the fire extinguisher effectively. P.A.S.S. stands for: Pull, Aim, Squeeze, Sweep, explained below the printable diagram.

• Pull the safety pin from the handle. The pin is located at the top of the fire extinguisher. Once removed, it releases the locking mechanism, allowing you to discharge the extinguisher.
• Aim the extinguisher nozzle or hose at the base of the fire. As explained, this removes the source or fuel of the fire. Keep yourself low.
• Squeeze the handle or lever slowly to discharge the agent. Letting go of the handle will stop the discharge, so keep it held down.
• Sweep side to side approximately 6in or 15cm over the fire until expended. The sweeping motion helps to extinguish the fire. Stand several feet or metres back from the fire: fire extinguishers are manufactured for use from a distance.
• The fire may flare up somewhat as extinguishing begins due to the flames being pushed away from the burning material (the real target) by the agent and gust of propellant. Do not be alarmed so long as it dies back promptly.