Answers!!
The fire tetrahedron components are: - ANSWERfuel, oxygen, heat, chemical
reaction. If you remove one side, the fire goes out
Theory of Fire - ANSWERfire is a rapid self sustaining oxidation accompanied by
heat & light of varying intensities
gases produced by combustion - ANSWERcarbon monoxide, carbon dioxide, sulfur
dioxide
how much oxygen must make up in atmosphere to burn - ANSWERat least 16%
(12% for smoldering fire)
Fire classes; A, B C, and D - ANSWERA: ordinary combustible materials, wood,
paper, cloth
B: flammable & combustable liquids, gases, greases
C: live electrical fires
D: combustable metals such as magnesium or sodium
Fire classes extinguished by - ANSWERA: cooling (water or multi purpose dry
chemical)
B: smothering, cooling, stopping chain reaction (CO2 extinguisher, dry chemical
extinguisher, foam, halon)
C: turn off all electrical or powered equipment then fight fire as A or B fires (CO2, dry
chemical, or halon)
D: chemical powders
Flashpoint - ANSWERLowest temperature at which a fuel gives off flammable vapors
in sufficient quantity to ignite & flash across the surface of the fuel
Flashpoint of different fuels - ANSWERgasoline (-45 F)
diesel (110 F)
What burns? - ANSWERvapor - not fuel
Conduction - ANSWERThe direct transfer of heat from one substance to another
substance that it is touching.
Prevent by removing or cooling combustibles
Convection - ANSWERThe transfer of heat by the movement of a heated air or liquid
Prevent by closing ventilation, ladder wells, doors
Radiation - ANSWERThe transfer of energy by electromagnetic waves without an
intervening medium
, Prevent by putting a barrier between the fire and combustibles (water, doors, fog,
etc)
Direct flame contact - ANSWERcombination of heat transfer by convection &
radiation at close range
Phases of fire development - ANSWERignition
growth
flashover
fully developed fire
Smoldering or decay
ignition - ANSWER4 elements of fire tetrahedron come together and flaming
combustion begins
growth - ANSWERa fire plume begins to form above burning fuel. Air drawn into
plume and convection causes heated gases to rise - continues of enough fuel and
oxygen are available
flashover - ANSWERA rapid transition from the growth stage to the fully developed
stage.
Occurs at 1000F-1500F
Signs of Flashover - ANSWERif heat is hot enough to make you drop to your knees
or rollover which is small flashes of flame appear at ceiling level or smoke pouring
out of top of window or doorway
fully developed fire - ANSWERall combustible materials in compartment are involved
in fire - burning fuels are releasing maximum amount of heat possible and produces
large amounts of unburned fire gases
foam - ANSWERcreates vapor tight blanket & cools
ADV- smothering & cooling agent, vapor barrier, Class B, tank fires, long lasting,
stays in place
DADV- conducts electricity, no class C or D, not suitable for gas fires, boiler/slop
over might exist
carbon dioxide - ANSWER1.5x heavier than air, but can exist as a liquid or solid
under pressure & is used for smothering a fire by diluting air until oxygen content is
too low to sustain combustion
ADV- non-conductive, effective for machinery spaces, no clean up required, effective
on high value cargo, effective use for HAZMAT
DADV- not effective on combustible metals, may suffocate anyone in a contained
area, limited cooling affect, slow
Temperature of a normal fire - ANSWERcoal burns at 3,590F
wood burns at 300F but can reach as high as 1600 F
hydrocarbon generates 1832 F within 10 minutes of ignition
most combustable metals in fire produce 5000F-8,500F