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Firefighting - Chapter 3
Fire Behavior
53
Other
Undergraduate 1
09/03/2012

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Term
Matter
Definition
anything that occupies space and has mass (weight)
Term
Oxidation
Definition
combination of oxygen with other materials (rust, combustion of methane)
Term
Exothermic
Definition
reaction that gives off energy (combustion)
Term
Endothermic
Definition
reaction that absorbs energy (creation of steam)
Term
Flaming combustion
Definition
oxidation of fuels in the gas phase
Term
Non-flaming combustion
Definition
oxidation of fuels at it's surface
Term
Fire Triangle
Definition
Oxygen, Fuel, Heat
Term
Fire Tetrahedron
Definition
Oxygen, Fuel, Heat, Self-sustained Chemical Reaction
Term
Difference between heat and temperature
Definition
one is a form of kinetic energy, the other is a measurement of kinetic energy
Term
Joules
Definition
measurement of heat energy (1 newton over 1 meter)
Term
Pyrolysis
Definition
chemical decomposition of a substance through the action of heat
Term
Piloted ignition
Definition
mixture of fuel and oxygen encounter an external heat source
Term
Autoignition
Definition
no external flame or spark to ignite the fuel gases or vapors
Term
Autoignition temperature (AIT)
Definition
temperature to which the surface of a substance must be heated for ignition and self-sustained combustion to occur; always higher than the piloted temperature
Term
Chemical heat energy
Definition
most common source of heat in combustion reactions; any combustible is in contact with oxygen
Term
Self-heating
Definition
'spontaneous heating'; chemical heat energy that occurs when a material increases in temperature without the addition of external heat (ex: oil-rag on the ground)
Term
Common spontaneous heating materials
Definition
charcoal, oil-soaked rags, hay and manure
Term
Resistance heating
Definition
heat produced while electric current flows through a conductor
Term
Overcurrent or overload
Definition
current flowing through a conductor exceeds its design limits, may overheat and become ignition hazard
Term
Arcing
Definition
high-temperature luminous electric discharge across a gap or through a medium (ex: lightning)
Term
Sparking
Definition
Electric arc where particles form and spatter away
Term
Mechanical heat energy
Definition
generated through friction or compression
Term
Conduction
Definition
transfer of heat from one body to another through direct contact (solid-to-solid)
Term
Convection
Definition
transfer of heat from a fluid (liquid or gas) to a solid surface
usually involves transfer of heat UP through hot smoke and gases
Term
Radiation
Definition
transmission of energy as an electromagnetic wave without a medium
as the temperature increases, the radiant energy increases by the FOURTH power
Term
Passive agents
Definition
materials that absorb heat bot do not participate actively in the combustion reaction (moisture of surface, humidity)
Term
Vapor density
Definition
density of gases in relation to air (with air being '1')
Term
Specific gravity
Definition
ratio of mass of a given volume compared to the mass of water (with water being '1')
Term
Flash point
Definition
temperature at which a liquid gives off sufficient vapors to ignite, but not sustain, combustion
Term
Fire point
Definition
temperature at which sufficient vapors are being generated to sustain combustion reactions
commonly used to indicate the flammability hazard of liquid fuels...at what temperature will it sustain being burned?
Term
Solubility
Definition
extent at which a substance will mix with water
miscibile materials will mix at any proportion
Term
Pryolysis Stage I
Definition
Less than 392F
moisture is released as wood begins to dry
Term
Pyrolysis Stage II
Definition
392 to 536F
majority of moisture has been released; charring has begun; primary compound being released is carbon monoxide; no ignition
Term
Pyrolysis Stage III
Definition
536 to 932F
combustible compounds are released and ignition can occur; charcoal formed by the burning process
Term
Pyrolysis Stage IV
Definition
Greater than 932F
Free burning wood exists as the wood material is converted to flammable gases
Term
Heat of combustion
Definition
total amount of energy released when a specific amount burns (expressed in kilojoules/gram)
Term
Heat Release Rate (HRR)
Definition
energy released per unit of time as the given fuel burns (expressed in kilowatts)
Term
Percentage of O2 in air
Definition
21% normally
Term
Oxidizers
Definition
not combustible, but, like oxygen, will support combustion
Term
Common oxidizers
Definition
calcium hypochlorite (chlorination of water in swimming pools); chlorine (water purification); ammonium nitrate (fertilizer); hydrogen peroxide (bleaching); methyl ethyl ketone peroxide (catalyst in plastic manufacturing)
Term
OSHA 29 CFR 1910.134
Definition
defines an atmosphere having less than 19.5% oxygen in the air as 'oxygen deficient' and a hazard to persons not on SCBA; concentrations exceeding 23.5% is 'oxygen enriched' and a fire risk
Term
Nomex
Definition
material in PPE that will not burn at normal O2 levels, but will in oxygen-enriched environments
Term
Flammable (explosive) range
Definition
range between the upper flammable limit and the lower flammable limit in which a substance can be ignited
needs the right mixture of fuel and oxidizer
Term
Hydrogen Cyanide (HCN)
Definition
produced through the combustion of materials containing nitrogen; prevents the body from using oxygen at the cellular level
byproduct of the combustion of polyurethane foam, which is commonly in furniture and bedding
Term
Fuel-controlled
Definition
Fire development is controlled by the characteristics and configuration of the fuel; ventilation does not matter
Term
Ventilation-controlled
Definition
Fire development is limited by air supply; fuel does not matter
Term
Thermal layering
Definition
Hottest gases tend to rise to the top layer
Term
Ghosting
Definition
pockets of flame moving through the hot gas layer above the neutral flame; indicator of developing flashover conditions
Term
Rollover
Definition
unburned fire gases accumlating at the top of the compartment ignite and flames propagate through the hot gas layer or across the ceiling
involvement is only of fire gases at the upper levels and not other fuel packages
generally precedes flashover, but not always resulting in it
Term
Flashover
Definition
rapid transition between the growth and fully developed fire stages
temperature in a compartment results in the simultaneous ignition of all the combustible contents in the space
NOT survivable
burning gases push out of the compartment at a substantial velocity
Term
Fully developed fire
Definition
all combustible materials in a compartment are burning
Term
Decay
Definition
fuel is consumed and energy release diminishes, and temperatures decrease
fire goes from ventilation-controlled to fuel-controlled again
Term
Backdraft
Definition
instantaneous explosion of superheated gases when oxygen is introduced into an oxygen-depleted confined space
doesn't need a horizontal opening; all that is required is mixing hot, fuel-rich smoke with air
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