CHAPTER 5 - FIRE BEHAVIOR Flashcards
1
Q
A rapid oxidation process, which is a chemical reaction resulting in the evolution of the light and heat in varying intensities.
A
Fire.
2
Q
A form of energy characterized by a vibration of molecules and capable of initiating and supporting chemical changes and changes of state.
A
Heat.
3
Q
Measure of a materials ability to transfer heat energy to other objects; the greater the energy, the higher the temperature.
A
Temperature.
4
Q
A material that will maintain combustion under specific environmental conditions.
A
Fuel.
5
Q
Any material that readily yields oxygen or other oxidizing gas, or that readily reacts to promote or initiate combustion of combustible materials.
A
Oxidizer.
6
Q
Anything that occupies space and mass.
A
Matter.
7
Q
Capacity to perform work; occurs when a force is applied to an object over a distance, or when a chemical, biological, or physical transformation is made in a substance.
A
Energy.
8
Q
Chemical process that occurs when a substance combines with an oxidizer such as oxygen in the air.
A
Oxidation.
9
Q
Stored energy possessed by an object that can be released in the future to perform work once released.
A
Potential energy.
10
Q
The energy possessed by a body because of its motion.
A
Kinetic energy.
11
Q
Defined in terms of mechanical energy. It is equal to the energy expended in applying a force of 1 N through a distance of matter. Energy required to increase temperature 4.2 J raises raises 1 g of water 1°.
A
Joules.
12
Q
Chemical reaction that releases thermal energy or heat.
A
Exothermic reaction.
13
Q
Chemical reaction that absorbs thermal energy or heat.
A
Endothermic reaction.
14
Q
Chemical decomposition of a solid material by heating. Often precedes combustion.
A
Pyrolysis.
15
Q
Physical process that changes a liquid into a gaseous state; the rate of vaporization depends on the substance involved, heat, pressure, and exposed surface area.
A
Vaporization.
16
Q
The process of initiating self sustained combustion.
A
Ignition.
17
Q
Moment when a mixture of fuel and oxygen and counters an external heat source with sufficient heat or thermal energy to start the combustion reaction.
A
Piloted ignition.
18
Q
Initiation of combustion by heat but without a flame or spark.
A
Auto ignition.
19
Q
The lowest temperature at which a combustible material ignites in the air without a spark or flame.
A
Autoignition temperature.
20
Q
Visible, luminous body of burning gas emitting radiant energy including the light or various color given off by burning gases or vapors during the combustion process.
A
Flame.
21
Q
A model used to explain the elements/conditions necessary for combustion. The sides of the triangle represent heat, oxygen, and fuel.
A
Fire triangle.
22
Q
Model of four elements/conditions required to have a fire. The four sides represent fuel, heat, oxygen, and self-sustaining chemical chain reaction.
A
Fire tetrahedron.
23
Q
Materials that absorb heat but do not participate actively in the combustion process.
A
Passive agent.
24
Q
Materials produced and released during burning.
A
Products of combustion.
25
Colorless, odorless us, dangerous gas formed by the incomplete combustion of carbon. It combines with hemoglobin more than 200 times faster than oxygen, the decreases the blood's ability to carry oxygen.
Carbon monoxide
26
Colorless, toxic, flammable liquid until it reaches 79°F. Above that temperature, it becomes a gas with a faint odor similar to better almonds produced by the combustion of nitrogen bearing substances.
Hydrogen cyanide.
27
Colorless, odorless, heavier than air gas that neither supports combustion nor Burns; used in portable fire extinguishers as an extinguishing agent to extinguish class B or C fires by smothering or displacing oxygen.
Carbon dioxide.
28
The kinetic energy associated with the random motions of the molecules of a material or object. Often used interchangeably with the terms heat and heat energy. Measured in joules or BTU.
Thermal energy.
29
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.
30
Initiation of combustion of a material by an internal chemical or biological reaction that has produced sufficient heat to ignite the material.
Spontaneous ignition
31
The measure of the rate of transfer to a surface.
Heat flux.
32
Transfer of heat through or between solids that are in direct contact.
Conduction.
33
Heat transfer by circulation within a medium such as a gas or a liquid.
Convection.
34
Heat transfer by way of electromagnetic energy.
Radiation.
35
The tendency or capacity to remain a float in a liquid or rise in air or gas.
Buoyant.
36
Composed of at least one inlet opening, one exhaust opening, and the connecting volume between openings. The direction of the flow is determined by difference in pressure. Heat and smoke and high-pressure area will flow to low-pressure area.
Flow path.
37
Buoyant layer of hot gases and smoke produced by a fire in a compartment.
Upper layer.
38
The fuel that is being oxidized or burned during combustion.
Reducing agent.
39
Total amount of thermal energy that could be generated by the combustion reaction if a fuel were completely burnt. Measured in BTU per pound or megajoules per kilo gram.
Heat of combustion.
40
Total amount of heat released per-unit time. Measured in kilowatts and megawatts of output.
Heat release rate (HHR).
41
A unit of measure of power or rate of work equal to one joule per second.
Watt.
42
Weight of a given volume of pure vapor or gas compared to the weight of an equal volume of dry air at the same temperature and pressure.
Vapor density.
43
Mass of a substance compared to the mass of an equal volume of water at a given temperature.
Specific gravity.
44
Any liquid having a flashpoint below 100° and a vapor pressure not exceeding 40 psi absolute.
Flammable liquid.
45
Measure the tendency of a substance to a evaporate. The pressure at which the vapor is in equilibrium with its liquid phase for a given temperature. Liquids that have a greater tendency to evaporate have higher vapor pressure for a given temperature.
Vapor pressure
46
Minimum temperature at which a liquid gives off enough vapors to form and ignitable mixture with air near the liquid surface.
Flashpoint
47
Temperature at which a liquid fuel produces sufficient vapors to support combustion once the fuel is ignited. Fuel point must exceed five seconds of burnt duration during the test.
Fire point.
48
Degree to which a solid, liquid, or gas dissolves in a solvent.
Solubility.
49
Materials that are capable of being mixed in all proportions.
Miscible.
50
Petroleum-based organic compound that contains only hydrogen and carbon.
Hydrocarbon fuel.
51
Flammable liquids that have an attraction for water, much like a positive magnetic pole attracts a negative pole; examples include alcohol, Keytone, and lacquer.
Polar solvents.
52
Liquid having a flashpoint out or above 100°F and below 200°F
Combustible liquid.
53
The range between the upper flammable limit and lower flammable limit in which a substance can be ignited.
Flammable range.
54
Limit at which a flammable gas or vapor will ignite; above this limit the gas or vapor is too rich to burn.
Upper flammable limit.
55
Limit at which a flammable gas or vapor will ignite and support combustion; below this limit the gas or vapor is to lean or too thin to burn.
Lower flammable limit.
56
Molecular fragments that are highly reactive.
Free radicals
57
Extinguishment of a fire by interruption of the chemical chain reaction.
Chemical flame inhibition.
58
A fire with adequate oxygen in which the heat released rate and growth rates are determined by characteristics of the fuel, such as quantity and geometry.
Fuel controlled.
59
A fire with limited ventilation in which the heat released rate or growth rate is limited by the amount of oxygen available to the fire.
Ventilation controlled.
60
Common, prevailing, and uncontrolled atmosphere of weather conditions. The term may refer to the conditions inside or outside of the structure.
Ambient conditions.
61
The total quantity of combustible contents of a building, space, or fire area. Including interior finish and trim, expressed in heat units of the equivalent weight in wood.
Fuel load.
62
First stage of the burning process in a compartment and which the substance being oxidized is producing some heat, but the heat has not spread to other substances nearby. Oxygen has not really been reduced and temperature is not too much higher than room temperature.
Incipient stage.
63
The column of hot gases, flames, and smoke rising above a fire; also called convection column, thermal updraft, or thermal column.
Plume.
64
A relatively thin layer of flowing hot gases that develops under a horizontal surface. As a result of plume impingement and the flowing gas being forced to move horizontally.
Ceiling jet.
65
Outcome of combustion in a confined space in which gases tend to form in layers, according to temperature, with the hottest gases found at the ceiling and the coolest at the floor.
Thermal layering
66
The level at a compartment opening where the difference in pressure exerted by expansion and buoyancy of hot smoke flowing out of the opening and the inward pressure of cooler, ambient temperature air flowing in through the opening is equal.
Neutral plane.
67
A rapid transition from the growth stage to the fully developed stage.
Flashover.
68
A condition where the unburned fire gases that have accumulated at the top of the compartment ignite and flames propagate through the hot gas layer or across the ceiling.
Rollover.
69
The explosive burning of heated gases that occurs when oxygen is introduced into a compartment that has a high concentration of flammable gases and depleted supply of oxygen due to an existing fire.
Backdraft.
70
Form of fire gas ignition; the ignition of accumulated flammable products of combustion and air that are within their flammable range.
Smoke explosion.
71
Planned, systematic, and coordinated removal of heated air, smoke, gases or other airborne contaminants from a structure. Replacing them with cooler and/Or fresher air to meet the incident priorities of life safety, incident stabilization, and property conservation.
Tactical ventilation.
72
Most commonly found oxidizer is the oxygen found in the air. True or false?
True.
73
All energy remains in the same form until it is expanded. True or false?
True.
74
The energy necessary for ignition of the fire is only provided by an extra no source. True or false?
False – autoignition occurs when two chemicals come together to create a combustible reaction.
75
Auto ignition temperature is sometimes higher than a few walls pilot ignition temperature. True or false?
False – temperature is always higher.
76
Combustion is a chemical reaction that can occur without fire. True or false?
True.
77
Most products of combustion are toxic and present a significant threat to human life. True or false?
True.
78
Smoke may contain unburned fuel. True or false?
True.
79
Thermal energy is never in transit from one location to another. True or false?
False – it is always in transit.
80
Conduction is the reason firefighters me feel an increase in temperature one working and I'll flowpath. True or false?
False – convection.
81
Heat released rate decreases one ventilation is limited. True or false?
True.
82
The primary consideration for ignition of solid fuels is surface to mass ratio. True or false?
True.
83
Nonflaming combustion can continue and extremely low concentrations when the surrounding temperature is low. True or false?
True.
84
Isolated flames may be observed moving through the gas later during the incipient stage of the fire. True or false?
False – this happens during the growth stage.
85
Temperatures in a decaying compartment fire do not remain high even after he released rate drops. True false?
False – temperatures remain high for sometime.
86
Wow a Fierstein you notice that fuel sources close to areas already on fire our igniting faster than those further away from the fire. What you are noticing as a result of the_____released during combustion.
Thermal energy.
87
Firefighting requires the correct use of SCBA to protect firefighters from gases, vapors, and solid particulates that are created during fire ground operations. This product of combustion that includes toxic and flammable gases, vapors, and particulates is most commonly referred to as_______.
Products of combustion.
88
Firefighters wear personal protective equipment during emergency operations to protect from a visible products of combustion this product is called______and becomes hotter and less luminous when mixed with proper amounts of oxygen.
Flame.
89
There are many firefighting methods, but the most common is cooling fuel with water. This method is called_______and works to reduce the temperature of fuel to the point that it does not produce sufficient vapor to burn.
Temperature reduction.
90
Of the firefighting methods available to use one method is the simplest. However, allowing the fire to burn until all the fuel is consumed, often called______is not always desirable.
Fuel removal.
91
Some firefighting methods will only work on specific types of fuels. For example, the method of______does not work if a fuel is self oxidizing.
Oxygen exclusion.
92
A reaction that emits energy as it occurs.
Exothermic
93
Type of ignition that occurs without any external flame or spark.
Auto ignition.
94
when a substance changes from one type of matter into another.
Chemical reaction.
95
Mode of combustion that occurs more slowly at a lower temperature producing a smoldering glow in a materials surface.
Nonflaming.
96
Form of heat transfer through and between solids.
Conduction.
97
The term that represents the amount of energy and object can release at some point in the future.
Potential.
98
The most common form of a mission that occurs when a mixture of fuel and oxygen encounter an external heat source with sufficient heat to start the combustion process.
Piloted.
99
Load of combustion that produces visible flame above a materials surface.
Flaming.
100
Form of heat transfer by circulation or movement of fluid.
Convection.
101
Heat transfer by the transmission of energy as an electromagnetic wave without an intervening medium.
Radiation.
102
When a substance remains chemically the same but changes in size, shape, or appearance.
Physical change.
103
A term that represents the energy possessed by a moving object.
Kinetic energy.
104
A reaction that absorbs energy as it occurs.
Endothermic.
105
All forms of fire involve a keep producing chemical reaction between:
Fuel and an oxidizer.
106
What products of combustion prevents The body from using oxygen on the cellular level?
Hydrogen cyanide.
107
What products of combustion increases respiratory rate?
Carbon dioxide.
108
Why must firefighters were SCBA during overhaul?
Hazardous concentrations with them short-term exposure limits are present.
109
What method of electrical energy is defined as particles that can be formed and spatter away from the point of arcing?
Sparking.
110
The movement of two surfaces against each other creates what source of thermal energy?
Mechanical.
111
What disrupts the point-to-point transfer of heat?
Insulating materials.
112
What best describes the influence of exposed surfaces on radiant heat?
Temperature differences between the heat source and exposed surface has a major effect on heat transfer.
113
What influences how easily a liquid can be ignited?
Vapor pressure.
114
What describes the impact of an extinguishing agent when trying to extinguish flaming combustion?
It terminates the combustion reaction
115
What thermal property of a compartment maintains the temperature by absorbing and releasing the large amounts of heat slowly?
Retention.
116
What common element of flashover requires the combustion to be in an enclosed space?
Compartment
117
What is an air flow indicator of a possible flashover?
High velocity and turbulent airflow.
118
What is an air flow indicator of a possible Backdraft?
Turbulent smoke discharge.
119
A chemical process of oxidation that occurs at a rate fast enough to produce heat and usually light in the form of either glow or flame.
Oxidation.
