CH 1 Flashcards
(106 cards)
1
Q
_______ describes the meeting point between fire science, materials science, fluid dynamics of gases, and heat transfer.
A
fire dynamics
pg 9
2
Q
Fire can take various forms, but all fires involve a heat-producing chemical reaction between some type of _______ and a(n) ________, most commonly oxygen in the air.
A
fuel; oxidizer
pg 9
3
Q
Chlorination of water in swimming pools
A
calcium hypochlorite (granular solid)
pg 9
4
Q
water purification
A
chlorine (gas)
pg 9
5
Q
fertilizer
A
ammonium nitrate (granular solid)
pg 9
6
Q
industrial bleaching (pulp and paper and chemical manufacturing)
A
hydrogen peroxide
pg 9
7
Q
catalyst in plastics manufacturing
A
methyl ethyl ketone peroxide
pg 9
8
Q
A _______ occurs when a substance remains chemically the same but changes in size, shape, or appearance.
A
physical change
pg 10
9
Q
A _______ occurs when a substance changes into another substance, such as two or more substances combining to form compounds.
A
chemical reaction
pg 10
10
Q
This potential energy available for release in the combustion process is known as the
A
heat of combustion
pg11
11
Q
1 055 J = ___ BTU
A
1
pg 11
12
Q
A fuel’s potential energy releases during combustion and converts to
A
kinetic energy
pg 11
13
Q
Reactions that emit energy as they occur are
A
exothermic reactions
pg 11
14
Q
Reactions that absorb energy are
A
endothermic reactions
pg 11
15
Q
______ is the most common form of ignition.
A
piloted ignition
pg 12
16
Q
_______ occurs without any external flame or spark to ignite the fuel gases or vapor.
A
autoignition
pg 12
17
Q
_______ is the minimum temperature at which a fuel in the air must heat to start self-sustained combustion.
A
autoignition temperature (AIT)
pg 12
18
Q
The autoignition temperature of a substance is always higher than its ____________ temperature.
A
piloted ignition
pg 12
19
Q
___________ combustion requires liquid or solid fuels to convert to the gas phase through the addition of heat (vaporization or pyrolisis, respectively).
A
flaming
pg 14
20
Q
________ is where the combustion process begins.
A
ignition
pg 14
21
Q
As the fire’s heat transfers to the gaseous combustion products, they expand and move away from the fire due to
A
buoyancy
pg 14
22
Q
As a fuel burns, its chemical composition changes, which produces new substances. These _______ are described as heat and smoke.
A
products of combustion
pg 14
23
Q
Complete combustion of _______ in air results in the production of heat, light, water, vapor, and carbon dioxide (CO2).
A
methane
pg 14
24
Q
Colorless, odorless gas. Inhalation of ________ causes headache, dizziness, weakness, confusion, nausea, unconsciousness, and death. Exposure to as little as 0.2% _________ can result in unconsciousness within 30 minutes.
A
carbon monoxide (CO)
pg 15
25
Colorless gas with a pungent, irritating odor that is highly irritating to the nose. ________PPM can cause severe irritation to the respiratory tract and serious injury. Exposure to high concentrations can cause injury to the skin. __________ is a suspected carcinogen.
50-100; formaldehyde
pg 15
26
Colorless, toxic, and flammable liquid below _____ degrees Fahrenheit produced by the combustion of nitrogen-bearing substances. It is a chemical asphyxiant that acts to prevent the body from using oxygen. It is commonly encountered in smoke in concentrations lower than
79; carbon monoxide
pg 15
27
Reddish-brown gas or yellowish- brown liquid, which is highly toxic and corrosive.
nitrogen dioxide
pg 15
28
Small particles that can be inhaled and deposited in the mouth, trachea, or the lungs. Exposure to _____ can cause eye irritation and respiratory distress (in addition to health hazards specifically related to the particular substances involved).
particulates
pg 15
29
Colorless gas with a choking or suffocating odor. Sulfur ________ is toxic and corrosive and can irritate the eyes and mucous membranes.
dioxide
pg 15
30
________ is a toxic and flammable product of the incomplete combustion of organic (carbon-containing) materials.
CO
pg 16
31
CO molecules attach to hemoglobin, decreasing the blood's ability to carry oxygen, as it combines with hemoglobin about ____ times more effectively than oxygen.
200
pg 16
32
_________ is a toxic and flammable substance produced in the combustion of materials containing nitrogen.
hydrogen cyanide (HCN)
pg 16
33
HCN is a significant byproduct of the combustion of ________ foam used in many household furnishings.
polyurethane
pg 16
34
_________ prevents the body from using oxygen at the cellular level.
HCN
pg 16
35
HCN is ___ times more toxic than CO.
35
pg 16
36
_______ is a product of complete combustion of organic materials.
CO2
pg 16
37
More than 20 irritants in smoke have been identified, including ________, formaldehyde, acrolein.
hydrogen chloride
pg 17
38
_________ measures the force per unit of area applied perpendicular to a surface.
pressure
pg 17
39
__________ always move from areas of higher pressure to areas of lower pressure.
gases
pg 17
40
Heated gases will rise, remain aloft (____________) and generally travel up and out of a compartment. At the same time, cooler, fresh air will generally travel toward the fire. This exchange of air creates a _________ flow.
buoyant; convective
pg 17
41
Ordinary, solid, combustible materials, such as wood, cloth, paper, rubber and many other plastics.
Class A
pg 18
42
Flammable, and combustible liquids, and gases, such as gasoline, oil, lacquer, paint, mineral spirits, and alcohol.
Class B
pg 18
43
Energized electrical equipment where the electrical nonconductivity of the extinguishing agent is of major importance. Materials involved are either Class A (wiring insulation) or Class B (lubricants), and they can be extinguished once the equipment is deenergized.
Class C
pg 18
44
Combustible metals, such as aluminum, magnesium, potassium, sodium, titanium, and zicronium. (Particularly in their powdered forms)
Class D
pg 18
45
Oils and greases normally found in commercial kitchens and food prep. Facilities using deep fryers.
Class K
pg 18
46
_________ is the thermal kinetic energy needed to release a fuel's potential chemical energy.
heat
pg 18
47
A dangerous misconception is that temperature accurately predicts or measures
heat transfer
pg 19
48
_________ energy is the most common source of heat in combustion reactions.
chemical
pg 19
49
_________, a form of oxidation, is a chemical reaction that increases the temperature of a material without adding external heat.
self-heating
pg 19
50
__________ energy can generate temperatures high enough to ignite any combustible materials near the heated area.
electrical
pg 20
51
Electric current flowing through a conductor produces heat.
resistance heating
pg 20
52
When the current flowing through a conductor exceeds design limits; the conductor may overheat and present an ignition hazard. __________ or _________ is unintended resistance heating.
overcurrent or overload
pg 20
53
An __________ is a high-temperature luminous electric discharge across a gap or through a medium such as charred insulation.
Arc/ arcing
pg 20
54
Friction or compression generates _________ energy.
mechanical
pg 21
55
The transfer of heat is part of the study of
thermodynamics
pg 21
56
____________ results from increased molecular motion and collisions between a substance's molecules, resulting in energy transfer through the substance.
conduction
pg 21-22
57
Copper will conduct heat more than ____ times faster than steel.
seven
pg 22
58
Steel is nearly _____ times as thermally conductive as concrete.
forty
pg 22
59
________ is the transfer of thermal energy by the circulation or movement of a fluid (liquid or gas).
convection
pg 22
60
In the fire environment, __________ usually involves heat transfer through the movement of hot smoke and fire gases.
convection
pg 22
61
Convection may occur in any direction. Vertical movement is due to the ________ of smoke and fire gases. Lateral movement usually results from __________ (movement from high to low).
buoyancy; pressure differences
pg 22
62
__________ is the transmission of energy as electromagnetic waves, such as light waves, radio waves, or X-rays, without and intervening medium.
radiation
pg 23
63
_______________ is the material or substance to be oxidized or burned in the combustion process.
fuel
pg 24
64
The fuel in a combustion reaction acts as the
reducing agent
pg 24
65
________ depends on fuel type, quantity, and orientation.
HRR
pg 25
66
For __________ combustion to occur, fuels must be in a gaseous state.
flaming
pg 27
67
Gaseous fuels, such as ______ (natural gas), ________, and _________, can be the most dangerous of all fuel types because they are already in the physical state required for ignition.
methane, hydrogen, and acetlyne
pg 27
68
_____________ indicates the minimum temperature at which a liquid gives off sufficient vapors to ignite, but not sustain combustion, in the presence of an ignition source.
flash point
pg 28
69
___________ marks the temperature at which a piloted ignition of sufficient vapors will begin a sustained combustion reaction.
fire point
pg 28
70
At normal ambient temperatures (68 degrees F) materials can ignite and burn at oxygen concentrations as low as
15%
pg 32
71
When placed in an oxygen-enriched atmosphere of approximately ____ oxygen, nomex ignites and burns vigorously.
31%
pg 32
72
The range of concentrations of a fuel vapor and air is called the
flammable range
pg 32
73
When confinement of the fuel vapors and air is not of concern, the measurement is expressed as a flammable limit (________) and a flash fire may occur.
LFL/UFL
pg 33
74
Electrically charged, highly reactive parts of molecules.
Free radicals
pg 33
75
___________ occurs when an extinguishing agent, such as a dry chemical or Halon-replacement agent, interferes with this chemical reaction, forms a stable product, and terminates the combustion reaction.
chemical flame inhibition
pg 33
76
The four stages of fire development
Incipient stage, Growth stage, Fully developed stage, Decay stage
pg 35
77
A visual indicator that a fire is leaving the incipient stage is flame height. When flames reach ___ft high, radiated heat begins to transfer more heat than convection.
2.5
pg 36
78
Rapid fire development usually occurs during the
growth stage
pg 37
79
The area where air is available to feed the fire
combustion zone
pg 37
80
When a fire cannot grow without the introduction of a new fuel or oxygen source, it has left the growth stage and become
fully developed
pg 37
81
___________ is the tendency of gases to form into layers according to temperature, gas density, and pressure.
thermal layering
pg 38
82
The ________ is the space between the air intake and the exhaust outlet.
flow path
pg 38
83
The appearance of ________ is sometimes an immediate indicator of flashover.
isolated flames
pg 39
84
__________ refers to the rapid transition from the growth stage or early decay stage to ventilation-limited, fully developed stage.
rapid fire development
pg 41
85
Rapid fire development events include: flashover, ___________, and smoke explosions.
backdraft
pg 41
86
Rapid transition from the growth stage to the fully developed stage is
flashover
pg 42
87
Flashover typically occurs during the fire's __________, but it may occur during the fully developed stage resulting from change in ventilation.
growth stage
pg 42
88
___________ describes a condition where the unburned fire gases accumulated at the top of a compartment ignite, and flames propagate through the hot gas layer or across the ceiling.
rollover
pg 42
89
During flashover, the volume of burning gases can increase from approximately ______ to ______ of the room's upper volume to fill.
1/4 to 1/2
pg 42
90
The autoignition temperature of CO, the most abundant fuel gas created in most fires, is approximately
1,100 degrees F
pg 43
91
A ventilation-limited compartment fire can produce a large volume of flammable smoke and other gases due to incomplete combustion.
backdraft
pg 44
92
Backdraft occurs in a space containing a high concentration of heated flammable gases that lack sufficient oxygen for
flaming combustion
pg 45
93
A __________ occurs when a mixture of unburned fuel gases and oxygen encounters an ignition source.
smoke explosion
pg 45
94
The __________ stage occurs when the fire's HRR has peaked because of lack of either fuel or oxygen.
fully developed
pg 46
95
There are two main types of fully developed fires:
ventilation-limited; fuel-limited fires
pg 46
96
The flow path is composed of two regions:
the ambient air flow in; the hot exhaust flow out
pg 49
97
In the ___________, the ambient air (higher pressure) flows towards the seat of the fire (lower pressure) and reacts with the fuel.
intake flow
pg 49
98
In the __________, the products of combustion (higher pressure) flow away from the fire toward the low-pressure outlet. Products of combustion always flow away from the fire toward any low-pressure outlet.
exhaust flow
pg 49
99
When hot gases follow the flow path from areas of high to low pressure, they __________ heat to a larger portion of the structure.
convect
pg 50
100
When the fire originates in a low level, such as in the basement or on the first floor, convected heat currents cause vertical extension through
atriums, stairways, vertical shafts, concealed spaces
pg 55
101
Tactics employed for fire suppression, ventilation, and search and rescue directly relate to the _________ occurring at a given incident.
fire dynamics
pg 51
102
Any open space with no complete dividing fire barrier is considered a
compartment
pg 58
103
In single-family residential structures, the square footage of houses increased over ____ between 1973 and 2008.
150%
pg 58
104
Unprotected engineered steel and wooden trusses can fail after ____ to ____ minutes of fire exposure.
5 to 10
pg 60
105
For steel trusses, _________ is the critical temperature of steel- the temperature at which steel begins to weaken.
1,000 degrees F
pg 60
106
An arched or a curved outline often indicates a
bowstring truss roof
pg 61
