1- Chapter Review Questions 1. Define the terms fire and combustion and explain the difference between them. Fire is the process of rapid oxidation that produces heat, light, and flame. Combustion is a chemical reaction in which a combustible material and an oxidizing agent produce heat or energy and other products that continuously sustain or promote the process. The combustion process released energy stays in the reaction, and fire is a form of combustion that emits and dissipates energy in the form of heat and light. 2. Define the term oxidation. Oxidation is the process of combining a substance or material with oxygen. 3. List the three legs of the fire triangle. Fuel, heat, and oxygen 4. List the four legs of the fire tetrahedron. Fuel, heat, oxygen, and chemical reaction 5. Using the fire tetrahedron, describe four methods of fire extinguishment. Cooling, oxygen reduction, removing the fuel supply, and interrupting the chain reaction 6. List the different classifications of fire and give a practical example of each. Class A- wood (ordinary combustibles) Class B- grease (combustible liquid and gases) Class C- office with plugged in computers (energized electrical equipment) Class D- magnesium (combustible metals) Class K- vegetable oils (cooking oils) 7. List the types of fire and explain each. Diffusion flame: The flame we see when we light a candle or match due to the process by which the gas fuel and oxygen move into the reaction zone of a flame. Smoldering: This is what we see when a cigarette is burning. This is caused by sufficient are flowing over the surface area the of material to provide enough oxygen to sustain a slow combustion. Spontaneous Combustion: This is when a fire starts and there was no known external heat source. This happens when a material starts to break down chemically resulting in heat that cannot dissipate and eventually fire will start. Premixed Flame: An example of this is the flame out of a gas stoe. This is a process of mixing a fuel and oxygen before ignition. 8. List the stages of fire growth and explain each. Preignition: This stage requires some form of energy transfer that generates gas from a fuel so the fuel can mix with air. Ignition: This occurs when the heat source, fuel, and oxygen come together to generate to promote a chain reaction. Growth: The energy level begins to grow by consuming the air and materials necessary to generate a flammable gas and sustain combustion. Fully Developed: The combustible contents of the compartment are totally in flame. Decay: The available fuel is exhausted or the oxygen level has dropped below 16%. 9. Define the term flashover. A flashover occurs between the growth and fully developed stage. When all the contents of a room heat to the ignition point and simultaneously ignite is a flashover. 10. List the methods of heat transfer and give a practical example of each.
Conduction is the transfer of heat by direct contact. This can be by heating a pan by placing it on a flame. Convection is the transfer of heat through a medium, such as heating an egg in boiling water. Radiation is the transfer of heat through energy such as light. The sun radiates its heat onto earth.