Chapter 5 Fire Behavior Flashcards
Physical science is the study of …… and …… and includes chemistry and physics.
matter and energy
Anything that occupies space and has mass.
Matter
What type of change occurs when a substance changes in size, shape or appearance, but the chemically stays the same?
Physical Change Ex: Water freezing, Water boiling
What type of change occurs when a substance changes from one type of matter to another?
Chemical change
When two or more substances combine they form a?
Compound
A chemical reaction involving the combination of a oxidizer, with another material.
Oxidation
The capacity to perform work.
Energy
Stored energy possessed by an object that can be released in the future to to perform work once released.
Potential Energy
The energy possessed by a body because of its motion.
Kinetic Energy
List seven types of energy.
chemical, thermal, electrical, mechanical, light, nuclear, sound
Can all energy change from one type to another?
Yes
In terms of a fire, the potential chemical energy of a fuel is converted to thermal energy and released as?
Heat
Name the measure of energy in the International System of Units (SI) and also for the customary system.
SI = Joules (J) Customary = Btu
How many joules does it take to change the temperature of one gram of water by one degree Celsius?
4.2 joules
The amount of heat required to raise the temperature of 1 pound of water 1 degree Fahrenheit.
Btu
How many joules = 1 Btu?
1055J
Reactions that emit energy are called?
Exothermic ex: fire
Reactions that absorb energy are called?
Endothermic ex: converting water to steam.
A chemical process of oxidation that occurs at a rate fast enough to produce heat and usually light in the form of either a glow or a flame?
Combustion
A rapid oxidation process, which is a chemical reaction resulting in the evolution of light and heat in varying intensities?
Fire
A form of energy characterized by vibration of molecules and capable of initiating and supporting chemical changes and change of state.
Heat
Measure of a materials ability to transfer heat energy to other objects.
Temperature.
A material that will maintain combustion under specific environmental conditions.
Fuel
Any material that readily yields oxygen or other oxidizing gas, or that readily reacts to promote or initiate combustion of combustible materials.
Oxidizer
Name two forms of ignition.
Piloted and auto (nonpiloted)
The most common type of ignition. Occurs when a mixture of fuel and oxygen encounter an external heat source with sufficient heat or thermal energy to start the combustion process.
Piloted Iginition
Occurs with out any external flame or spark to ignite the fuel gases and vapors.
Auto Ignition
The auto ignition temperature of a substance is always higher then its …………
Piloted ignition temperature
The chemical decomposition of a solid material by heating. Often precedes combustion.
Pyrolysis
Physical process that changes a liquid into a gaseous state; the rate depends on the substance involved, heat, pressure, and exposed surface area.
Vaporization
The process of initiating self sustained combustion.
Ignition
Pyrolysis occurs in what type of fuel
solids
Vaporization occurs in what type of fuel?
Liquids
The lowest temperature at which a combustible material ignites in air without a spark or a flame.
Autoignition Temprature (AIT)
True or False Combustion is a chemical reaction while fire is possible result of combustion.
True
Name two modes of combustion.
Flaming and nonflaming
Occurs slowly, lower temps, produces a smoldering glow.
Nonflamming combustion
Produces a visible flame above the materials surface.
Flaming combustion
Name the two models that are used to describe the element of fire and how to extinguish it.
Fire Triangle, Fire Tetrahedron
Materials that absorb heat but do not participate actively in the combustion process. Given a example.
Passive Agents. ex: Gypsum/Humidity
Smoke is a product of incomplete combustion. It is a aerosol comprised of what?
gases, vapor, and solid particulates
Materials produced and released during burning.
Products of combustion.
A toxic and flammable product of incomplete combustion of organic materials. The most common product of combustion encountered in structure fires. Chemical asphyxiant that binds with hemoglobin preventing O2 from binding with it.
Carbon Monoxide (CO)
Toxic, flammable, produced in the combustion of materials containing nitrogen. Chemical asphyxiant that prevents the body from using O2 at the cellular level.
Hydrogen Cyanide (HCN)
Product of complete combustion of organic material, acts as a simple asphyxiant by displacing O2, also stimulates respiratory system causing increase in resp rate,
Carbon Dioxide (CO2)
Substances that cause breathing discomfort. Inflammation of the eyes, resp tract, and skin.
Irritants
How many irritants have test shown are in smoke? Give three examples.
- hydrogen chloride, formaldehyde, acrolein
True or False. Flame is also considered to be a product of combustion?
True
The kinetic energy associated with the random motions of the molecules of a material or object.
Thermal Energy. aka: heat and heat energy
the measurement of heat.
Temperature
Equation. Celsius to Fahrenheit
F = (C x 1.8) + 32
Equation: Fahrenheit to Celsius
C = (F -32) / 1.8
Name six sources of thermal energy.
Chemical, Mechanical, Electrical, Light, Nuclear, Sound
The most common source of heat energy in combustion.
Chemical
The result of exothermic reactions, occurring spontaneously in some materials under certain conditions, whereby heat is generated at a rate sufficient to raise the temperature of the material.
Self-Heating
Initiation of combustion of a material by an internal chemical or biological reaction that has produced sufficient heat to ignite the material.
Spontaneous Ignition
Name three things that must happen for spontaneous ignition to take place.
heat can not dissipate faster then it is produced, materials temp must reach its auto ignition temp, available air must be able to support combustion.