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FIRE AND FIREFIGHTING - 12018_414
METHODS OF HEAT TRANSFER - 12018_416

Basic Military Requirements (BMR) - Requirement for military advancement
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Practice good housekeeping procedures, such as the daily removal of trash from spaces. Practice safety precautions when working with flammable materials. Report all potential fire hazards. Keep firefighting equipment handy and in good working order. Ensure  closures  and  fittings  are  working properly and report any discrepancies. FIRE TRIANGLE The  entire  chemistry  and  physics  of  fire  and burning,  or  combustion,  can  be  simplified  into  a relationship  between  three  components—fuel,  heat (temperature), and oxygen (air). To have a fire in any combustible substance, each one of these components must  be  present  to  help  each  other.  Picture  these components in the form of a triangle, as shown in figure 12-7. Look at figure 12-7. Here, you can see that if the oxygen reacts with the fuel, it creates heat, which causes a  draft  or  some  other  condition  that  takes  in  more oxygen and creates still more heat, and so on. Or the heat may cause more fuel to become available (such as causing gasoline to boil into vapor), which then takes more oxygen to burn and creates more heat, which then produces still more fuel, and so on. The burning reaction can go in many different directions. The  modern  science  of  firefighting  and  fire extinguishment is based on the sides of the fire triangle and  an  uninhibited  chain  reaction  of  burning. Obviously, the firefighter can remove one or more of the components to cause the burning to stop. The type of firefighting agent the firefighter has at hand determines which component or components of the triangle will be removed. Another way the firefighter can stop the fire (and the combustion)  is  to  place  a  screen  between  any  two components of the triangle. If the fighter uses an agent as a temporary screen that breaks the triangle, the fire goes out. Obviously, the fire can quickly start up again if this method is used because each of the three necessary components is still there waiting to start the fire again once the screen is gone. FIRE TETRAHEDRON The  fire  triangle  describes  the  requirements  for surface  glowing  or  smoldering,  but  it  doesn’t completely describe flaming combustion requirements. A fourth requirement, an uninhibited chain reaction, is needed for flames to exist. This is shown by the fire tetrahedron (fig. 12-8). A tetrahedron is a solid figure with four triangular faces. It is useful for illustrating the flaming combustion process because it provides for the chemical  chain  reaction  requirement  and  each  face touches the other three sides. As described for the fire triangle, flaming combustion stops when one of the four sides of the fire tetrahedron is removed. SPONTANEOUS COMBUSTION Fire, also called  burning  or  combustion, is a rapid chemical reaction that results in the release of energy in the  form  of  light  and  heat.  Most  spontaneous combustion involves very rapid oxidation; that is, the 12-19 Student Notes: Figure 12-7.—Requirements for combustion.







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