Fire Control Flashcards
(42 cards)
Thermal Burns can occur in which 3 ways?
contact with conducted heat source
Exposure to convection heat source
Exposure to radiant heat source
Exposure to temp of only __ to __ will cause extreme pain and severe full thickness burns
280-320
2nd degree burns can occur with exposure of
111 degrees, within 20 seconds of 131 degrees, one second of 158 degrees
Flashover exposes firefighters to temps of __ to ___ degrees
1100-1500
6 Measurable factors of Class A fires are
- input heat
- Fuel
- Oxygen
- Proportioning of the fuel/air mixture
- Mixing of the fuel/air mixture
- Uninhibited chain reactions between active fuel/air molecules
Is matter created or destroyed? (True False)
False, matter is neither created nor destroyed it merely undergoes changes
A BTU is
the amount of heat required to raise
the temperature of one pound of water one degree fahrenheit
Specific Heat is
the thermal
capacity of a substance. It is the number of BTU’s required to raise the temperature of one pound
of a substance one degree fahrenheit
Latent heat is
the quantity of heat absorbed by a substance when passing between phases. Solid
to liquid is the latent heat of fusion. Liquid to vapor is the latent heat of vaporization.
The latent heat fusion of water is
143 BTUs
The latent heat of evaporation is
970 BTUs
In what ways is heat transferred
radiation, conduction, convection
Radiation heat transfer is
when heat energy is transmitted similar to light waves. Radiant heat energy
emanates equally in all directions, in straight lines.
Convection is
the transmission, spread, or distribution of heat through the motion of a heated
fluid. Convection will cause a heated fluid to become buoyant and rise. It is the primary heat
transfer method within structures and is responsible for the majority of fire and smoke spread
within structures
Conduction is
the transfer of heat through matter without any visible motion of that matter.
This is the only method of heat transfer through solid objects.
What is the most dangerous product of combustion?
Heat
Why is heat the most dangerous product of combustion?
heat is carried to remote areas of the structure and contributes to fire extension
materials reach ignition temp through heat and result in rapid fire spread
metal to wood structures weaken, which can lead to collapse
The three stages of an interior fire are
growth, fully developed, decay
How long a fire goes through the growth stage are dependent on 6 factors
A. The amount of exposed combustible surface.
B. The arrangement of the combustible surfaces.
C. The type of fuel source.
D. The nature of the combustible surfaces.
E. The ratio of combustible surface to room or area volume.
F. The amount of available air flow or ventilation.
The rate of sustained Combustion is dependent upon what
availability of ventilation or air flow
Flashover occurs where in the 3 stages of fire
end of the growth stage and beginning of the fully developed stage
Flashover is defined as
Sudden full room or area involvement in flame, or the sudden auto ignition of
combustible surfaces and/or gases in an area heated by convection and/or radiation,
resulting in a sudden and intense rise in temperature.
What is the most dangerous stage of fire?
Flashover
Contributing factors of a quick flashover are-
use of synthetics that burn 2x 3x hotter
increase use of lightweight construction reduces structural mass, Higher surface area to mass ratios result in increased fire intensity and early
structural failure.
Building design with large open or undivided floor areas.
equipment insulates us from sensing the warning signs of rapid heat build up leading to flashover.
