9. Oxidizing Agent (oxygen) Those materials that yield oxygen or other Oxidizing gases during the course of a chemical reaction. Fuel The material or substance being oxidized or Burned in the combustion process.
10. Heat Heat is the energy component of the fire tetrahedron. When heat comes into contact with a fuel, the energy support the combustion reaction.
17. Flash Point The minimum temperature to which a liquid fuel gives off sufficient vapor that can be ignited momentarily by a flame. Fire Point The minimum temperature to which a liquid fuel gives off sufficient vapor to support continuous combustion.
18. Auto Ignition Temperature The minimum temperature at which a liquid fuel will ignite without the presence of a pilot flame or spark. Flammability Limit A flammable gas or vapor will only form in atmosphere if the flammable vapor and oxygen in air lies within certain limits. These limits are referred to us the lower and upper flammable or explosive limits.
19. SELF SUSTAINED CHEMICAL REACTION Combustion is a complex reaction that requires a fuel, an oxidizer, and heat energy to come together in a very specific way. Fire can only continue when enough heat is produced to cause the continued development of flammable vapors or gases.
21. Class A Fires Fires that involves ordinary combustible materials such as wood, cloth, paper, rubber, and many plastics. wood cloth paper rubber plastics
22. Class B Fires Fires that involves flammable and combustible liquids and gases. Gases Oil Motor spirit Paints
25. Class K Class K is for fires in unsaturated cooking oils in well insulated cooking appliances in commercial kitchens.
27. Oxygen exclusion (smothering) The oxygen content can be reduced by flooding an area with an inert gas, which displaces the oxygen and disrupts the combustion process. Heat Fuel O 2 Chemical Chain Reaction
29. Fuel removal (Starvation) The fuel source may be removed by stopping the flow of liquid or gaseous fuel or by removing solid fuel in the path of fire. Heat Fuel O 2 Chemical Chain Reaction
30. Chemical flame inhibition (Breaking of chemical chain reaction) Extinguishing agents such as dry chemicals interrupt the combustion reaction and stop flaming. Heat Fuel O 2 Chemical Chain Reaction
32. The P.A.S.S. Method Pull the pin. Aim the hose or nozzle. Squeeze the lever. Sweep the agent.
33. WATER The direct effect is to cool down the unburned product, stop the evolution of vapor and starve the flame gradually until complete extinguishment. USAGE: Cooling/Quenching Displacing spills Handling clouds Making Foam Protecting personnel
36. CARBON DIOXIDE Brings the fuel/air mixture in the fire area below the lower flammable limit. The air and therefore, the oxygen concentration is reduced to such a level that the fire cannot sustain itself. General Characteristics of CO 2 Provides its own pressure for discharge Non-reactive to most substances Emerges as a gas which can penetrate all parts of fire area Non-conductor of electricity (Best for Class C fires)
40. TRANSMISSION OF HEAT Convection Convection is the transfer of heat energy by the movement of heated fluids. HEAT
41. TRANSMISSION OF HEAT Radiation Radiation is the transmission of heat energy through electromagnetic wave.
42. RATE OF OXIDATION Oxidation Rusting Self-Heating Flammable Liquid Fire Explosion Very Slow (months) Hours Seconds Rapid Combustion maybe very slow or very rapid.
43. THE COMBUSTION PROCESS Heat Source Fuel (wood) Vapor produced Vapor broken down Air and fuel mix COMBUSTION Light Heat
44. HEAT AND TEMPERATURE Heat energy in transit An indicator of heat and is a measure of the warmth or coldness of an object based on standard arbitrary unit. HEAT Temperature
45. FIRE DEVELOPMENT Atmospheric condition flammable vapor coming out from the fuel is invisible. Incipient Stage 10% of the flammable vapor from the fuel is visible. Smoldering Stage flammable vapors are ignited and self propagating. Flaming Stage Generates sufficient heat to warm the air immediately around the fire. Heat Stage
46. FIRE DEVELOPMENT Confined Space Incipient Stage Full-blown Stage Burn-out Phase Flashover Ignition Growth Fully Developed Fire Decay Time
48. FIRE DEVELOPMENT Confined Space Ignition – describes the period when the four elements of fire tetrahedron come together and combustion begins. Growth – fire plume begins to form above the burning fuel. Flashover – transition between the growth and fully developed fire. Fully developed – all the combustible materials in the confined space are involved in fire. Decay – the rate of heat releases begins to decline.
52. Example: for 4 liter/300 bar cylinder Total air capacity = Cylinder capacity x Cylinder pressure = 4 x 300 = 1200 liters of air Total duration of = Total air capacity / Average consumption cylinder = 1200 / 40 = 30 mins Working Duration = Total duration - Safety factor = 30 mins - 10 mins = 20 mins