What are the conditions needed for a fire to occur? correct answers fuel (material that acts as a
fuel)
sources of ignition (chemical, biological, or physical)
oxygen
What are the components of the fire tetrahedron? correct answers heat, fuel, oxygen, chain
reaction
How do you stop a fire? correct answers Remove any of the components of the fire tetrahedron
(i.e. remove fuel, oxygen, heat, or interrupt the chemical reaction)
Oxygen correct answers -21% ambient air
-robust flaming combustion down to 15-16%
-surface combustion (smoldering) down to about 11%
-loss of consciousness in atmospheres with 12% or less oxygen
Heat correct answers anything that produces the required temperature for ignition
-sun
-open flame
-chemical reaction
-sparks
-friction
Fuel correct answers -only vapors burn
-liquids and solids must first be vaporized
-tendency of a substance to vaporize is an indication of its ability to burn
-liquids vaporize more readily than solids
Chain reaction correct answers -you can have oxygen, heat, and fuel in the same place and still
not have a fire
-fuel and oxygen relationship must be balanced (i.e. in the flammable range)
-heat must be sufficient to bring fuel to its ignition
What is a flash point (of a liquid)? correct answers -the lower temp that a liquid can give off
sufficient gas to form a flammable gas mixture near the surface of a liquid
-lowest temp at which we can have fire
-fire flashes across surface given sufficient oxygen and an external source of ignition
What is a Fire point? correct answers -just above the flash point, liquid gives off flammable
vapors rapidly enough to support continuous combustion
What is ignition temperature? correct answers -substance starts to burn
-heat from external heat source
-auto-ignitio, no external source of ignition needed
, What is auto ignition? correct answers vapor generated ignites without any outside ignition
source
What is vaporization? correct answers rate increases with temperature
What is spontaneous combustion? correct answers heat is generated by a chemical action within
a substance and this continues until you have ignition (usually begins with oxidation and
combines oxygen and gives off energy in the form of heat)
What is lower flammable limit? correct answers the least concentration of flammable vapors in
air that will burn
What is upper flammable limit correct answers the greatest concentration of flammable vapors in
the air that will burn
What are the results of combustion? correct answers smoke, flame, heat, and gases
_____________ is the result of incomplete combustion correct answers smoke
White or light grey indicates ____________ burning correct answers free
Black or dark grey indicates a ______ fire or a _________ of oxygen correct answers hot, lack
How is flame produced? correct answers result of conversation of the fuel to a state of blazing
combustion
How is heat generated? correct answers rapid oxidation of the material
How are gases produced? correct answers result of combustion, may or may not be toxic
What are the characteristics of the incipient stage of a fire? correct answers -cool
-good combustion
-little smoke
-good visability
-easy to breath
-radiative feedback
What are the characteristics of the freeborn stage? correct answers -hot
-poor combustion
-dense smoke
-poor visibility
-can't breath
What are examples of a Class A fire? correct answers wood, paper, rubber, plastic