Fire Science.txt

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Fire Science.txt
2011-11-27 21:34:38
Fire Science

Fire Science
Show Answers:

  1. Explain the fire triangle
  2. 3 states of matter
    • Solid
    • Liquid
    • Gas
  3. Define pyrolysis
    heat causes matter to offgas and it is the offgassing that ignites
  4. Define fire
    A rapid chemical reaction that produces a release of energy in heat and light
  5. What are the 3 byproducts of combustion?
    • Smoke
    • Flame
    • Heat
  6. Define smoke and what elements can be found within smoke.
    • Smoke is a visible product of incomplete combustion
    • O2, Nitrogen, CO, CO2, carbon, fine soot
  7. How does heat transfer?
    Heat transfers to cold
  8. What are 3 methods of heat transfer?
    • - conduction
    • - Radiation
    • - Convection
  9. Class A
    Normal combustable material
  10. Class B
    Flammable liquid
  11. Class C
  12. Class D
    Combustable metals
  13. Class K
    Cooking oils and fats
  14. What are the 4 phases of fire?
    • Ignition
    • Growth
    • Fully developed
    • Decay
  15. What is the difference between Flashover and backdraft?
    • Flashover - There is an abundance of O2 present and typically takes place during growth or fully developed fire
    • Backdraft - There is a lack of O2 present until you open a window or door, typically in the later stages of fire
  16. Is puffing smoke is a sign of possible flashover or backdraft?
  17. Flashpoint?
    Lowest temperature which a substance will give a suficient vapour to ignite
  18. Flame point?
    • Also known as Ignition temperature
    • Lowest temperature which a substance will give a suficient vapour to sustain fire
  19. What makes a substance flammable?
    • Any liquid having a flashpoint below 38 degrees celcius and a vapour pressure not exceeding 175KPA
    • (ex. gasoline)
  20. What makes a substance flammable?
    • Anything with a flashpoint above 38 degrees celcius
    • (ex. Diesel)
  21. Vapour density
    The higher the vapour desity, the faster the substance offgasses
  22. LEL / LFL?
    Lower explosion limit / Lower Flammable limit
  23. UEL / UFL?
    Upper explosion limit / Upper Flammable limit
  24. What are the 4 important factors when reading smoke?
    • Velocity
    • Volume
    • Colour
    • Density
  25. What is matter?
    • Made up of Atoms and Molecules
    • 3 states of matter: Solids, Liquid, Gasses
  26. Define a solid?
    • - under normal conditions it retains a definate size and shape
    • - contracts when cooled and expands when heated
    • - may turn to a liquid
  27. Define a liquid?
    • - will assume shape of container
    • - most contract when cooled, expand when heated
    • - may turn to a solid or a gas
  28. Define a gas?
    • - tends to expand indefinitely
    • - may liquify
  29. What is a fuel?
    A form of energy
  30. Mechanical Energy is...
    • converted to heat when two serfaces rub together to create heat
    • - waterfall,
  31. Chemical energy...
    A chemical reaction that causes an exothermic or endothermic reaction (release or absorb heat)
  32. Light energy is...
    - electromagnetic waves traveling as thermal radiation, a form of heat
  33. Nuclear energy is...
    - Fission or fusionwhich release large amounts of heat energy
  34. Oxidation:
    Oxygen combining with something to form a new compound (ex. Rust)
  35. Combustion:
    Oxygen combining with something creates a rapid chemical process creating heat and light (fire)
  36. Pyrolysis:
    Decomposition of a material brought about by heat in the absence of oxygen
  37. Smoke:
    • Incomplete combustion due to a lack of oxygen
    • - solids
  38. **Conduction:
    Transfer of heat through matter by movement of kinetic energy from one partical to another
  39. **Convection:
    Circulatory movement that occurs in gas or liquids with areas of differing temperatures oweing to the variation of density and the action of gravity.
  40. **Radiation:
    Transfer of heat through the emmission of energy in te form of invisible waves
  41. What are the 4 ways to put out a fire?
    • 1. Cool the burning material
    • 2. Exclude oxygen
    • 3. Remove fuel
    • 4. Interupt the chemical reaction with a flame inhibitor
  42. What are the stages of a solid fuel fire?
    • 1. Ignition
    • 2. Growth
    • 3. Fully developed
    • 4. Decay
  43. What stage is Flashover possible?
    Fully developed
  44. Flameover?
    • - AKA rollover
    • Hot gasses rise up to the ceiling and when they reach a sufficient temperature they quickly ignite. burn and fall back down and get sucked back into the fire
  45. Volitility?
    Describes the amount and the ease of ability of the liquid to evaporate to create a flammible vapor-air mixture
  46. Vapour density?
    Weight of a gas as compaired to air
  47. BLEVE
    • Boiling liquid, expanding vapour explosion
    • - BIG propane tanks
    • - liquid boils & expands, relief valve opens, liquid levels fall to a point of the proper mixture then BOOM!
  48. Laminar Smoke flow?
    Relaxed, smooth smoke flow
  49. Turbulent smoke flow?
    Agitated, boiling or angry smoke flow
  50. Black Fire?
    • high volume, high velocity, turbulent, ultra dense black smoke
    • Very hot, impending flashover
  51. If you open a door and the smoke thins but is still in the doorway...
    You are above the fire
  52. If you open a door and the smoke dissappears into the room...
    You are below the fire
  53. If you open a door and the smoke exits the top half of the door and clean air is sucked in the bottom of the door...
    You are on the fire floor