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56 Cards in this Set

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Matter
anything that occupies space and has mass
3 states of matter
liquid, gas, solid
physical change
substance stays the same chemically but changes in size, shape, or appearance
ie water freezing
chemical changes
substance changes from one type of matter to another, often involves two or more substances that form other compunds
exothermic reaction
gives off energy (combustion)
endothermic reaction
absorbs energy
liquid to a gas (water to steam)
combustion
a rapid self sustaining chemical process that yields heat and sometimes light
Fire Triangle
heat, oxygen, fuel
describes smoldering combustion
fire tetrahedron
flaming combustion
fuel, heat, oxygen, self sustaining chemical reaction
what is heat?
-form of energy
-2 states (kinetic and potential)
in case of heat work means increasing temperature
potential energy
energy possessed by an object that be released in the future
kinetic energy
energy possessed by a moving object
Law of Conservation of Mass Energy
Mass and energy may be converted from one to another but there is never any net loss of total mass energy
temperature
measure of kinetic energy
heat energy will move from those of higher temps to those of lower temps
What is energy
capacity to perform work
cant measure directly( measure the work that energy performs)
sources of heat energy
common-mechanical, electrical, chemical
other-nuclear, light, sound
chemical heat energy
2 types
most common
any combustible in contact with oxygen
heat of combustion
self heating/spontaneous heating
spontaneous combustion
heat cannot dissipate
must reach autoignition temperature
poor ventilation
things that can spontaneous combust
charcoal, hay, manure, linseed oil rags
electrical heat energy
think ROAS
resistance
overload
arcing
sparking
Mechanical Heat energy
heat of compression (filling scba and diesel engine)
heat of friction-belt rubbing
measuring heat enrgy
BTU and calorie
BTU
British thermal unit
amount of heat it takes to heat 1 lb of water by 1 degree Fahrenheit
customary
calorie
amount of heat it takes to heat 1 gram of water by 1 degree celcius
si system
measuring work in Joules
what is a joule
-1 newton over a distance of 1 meter
4200 joules to heat 1 kilogram of water by 1 degree celcius
Fahrenheit v Celsius
f-water freezes at 32 and boils at 212

c- water freezes at 0 and boils at 100
3 methods of heat transfer
conduction, convection, and radiation
conduction
direct contact-closer the molecules of a substance the better it conducts electricity
convection
movement through air or liquid
usually through smoke and fire gases
hot up
radiation
heat and light waves
major cause of spread of fire
most dominant mode
Fuel (reducing agent) in solids broken down into?
inorganic-w/out carbon hydrogen or magnesium
organic- with carbon
hydrocarbons(gasoline, oil, plastics)
cellulose (wood and paper)
for flaming combustion to occur fuels must be in what state?
gaseous
pyrolysis
decomposition of a solid fuel by heat
begins at 400
ignition vapors range from 1000 to 1300
heat release rate (HRR)
energy released per unit of time as a given fuel burns
-expressed in kilowatts
reducing agent gas
(hydrogen methane, etc)
most dangerous form, ready to burn
vapor density
density of gases in relation to air
air is 1
less than 1 will rise
heavier than 1 sink
solubility of a liquid
hyrdorcarbon fuels- wont mix with water
polar solvent- will mix with water, methanol and ethanol
vaporization
transformation of a liquid to a vapor
must overcome atmospheric pressure 14.7 psi
flash point
temp at which a liquid gives of sufficient vapors to ignite but not sustain combustion
fire point
temp at which sufficient vapors are being generated to sustain the combustion process
specific gravity
ratio of the mass of a given liquid compared to the weight of of an equal amount of volume of water
water equals 1
-more than 1 sink
-lighter than 1 will float (gas and flamm liquids)
air is
21 percent oxygen
-19.5 percent considered oxygen deficient
-23.5 percent oxygen rich
oxidizing agent
supports combustion
lfl -to lean
ufl-too rich
products of combustion
light
flame
heat
smoke
smoke is what in regards to killer
number 1 in civilian and ff deaths
carbon monoxide
incomplete combustion
odorless, tasteless, colorless
combines 200 time quicker with hemoglobin than oxygen
carbon dioxide
complete combustion
displacing oxygen
hydrogen cyanide
chemical asphyxiate
-comes from polyurethane foam and other things
class d fires (some metals)
potassium, zinc, magnesium, sodium, titanium
class d does what with water
reacts violently because high temp
class k
saponification- alkaline based chemicals combines with cooking oils to form a soapy film
flashover
all objects have reached ignition temp 900- 1200 degrees f
fully developed
maximum hrr
limited by fuel and oxygen
vent controlled
decay
4th and final stage
backdraft
energy release rat and temps drop
goes back to fuel contolled
backdraft indicators
yellow grayish smoke
pressurized smoke exiting small openings
inwardly drawn smoke
smoke puffing
soot stained cracking windows
little or no visible flame
factors that affect fir development
-fuel types
-availability and location of other fuel
volume and ceiling height of compartment
-ventilation and changes in ventilation
-thermal properties to enclosure
-ambient conditions