NFPA 921 (CHAPTER 5) questions with correct answers

What is energy? CORRECT ANSWER Ability to perform work, either by moving over a distance against a force or by transferring heat. How is energy measured CORRECT ANSWER Joules, calories, or BTU's Define power CORRECT ANSWER Property that describes energy released per unit time. How is power measured? CORRECT ANSWER Joules per second or watts. Define heat flux CORRECT ANSWER The amount of power per unit area. What are the 4 components of the Fire Tetrahedron CORRECT ANSWER 1. Fuel 2. Heat 3. Oxidizing agent 4. Chemical chain reaction. What is fuel CORRECT ANSWER Any substance that can undergo combustion. What is the Oxidizing agent CORRECT ANSWER Oxygen in the earth’s atmosphere What is fire chemistry CORRECT ANSWER Study of chemical processes that occur in fires, including changes of state, decomposition, and combustion. define combustion CORRECT ANSWER Fuel and Oxidizing agent mixed (premixed burning) What is LEL CORRECT ANSWER Lower explosives limit--minimum % of fuel in air in which combustion can occur.