Chapter 4 Flashcards by Caitlin Untinen

The energy that a moving object possesses is known as: (119) [4.3.11]

A. kinetic energy
B. thermal energy
C. potential energy
D. exothermic energy

A. kinetic energy

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The type of chemical reaction in which a substance absorbs energy is an: (120) [4.3.11]

A. esoteric reaction
B. existential reaction
C. exothermic reaction
D. endothermic reaction

D. endothermic reaction

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Which model includes the chemical chain reaction to explain the gas-phase combustion of fire? (120) [4.3.11]

A. Fire triangle
B. Fire rectangle
C. Fire tetrahedron
D. Fire tetradagonal

C. Fire tetrahedron

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Which type of ignition occurs without any external heat or flame igniting the fuel? (120) [4.3.11]

A. Autoignition
B. Piloted ignition
C. Thermal ignition
D. Independent ignition

A. Autoignition

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Smoldering charcoal is an example of ______ combustion. (123) [4.3.11]

A. thermal
B. flaming
C. pyrolytic
D. nonflaming

D. nonflaming

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When the air supply to a fire is limited, the level of incomplete combustion is higher, which: (124) [4.3.11]

A. Limits smoke density
B. Produces more smoke
C. Improves firefighting conditions
D. Results in fewer products of combustion

B. Produces more smoke

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Which statement accurately describes the products of combustion produced in a structure fire? (124-126) [4.3.11]

A. Nitrogen dioxide is a toxic gas that is produced when synthetic materials are burned.
B. Carbon monoxide acts as a chemical asphyxiant and commonly causes civilian fire fatalities.
C. Carbon dioxide is the most dangerous product of combustion found in residential fires.
D. Hydrogen cyanide is only present and able to cause harm when the smoke is a dark gray or black color.

B. Carbon monoxide acts as a chemical asphyxiant and commonly causes civilian fire fatalities.

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A toxic and flammable byproduct of combustion that is 35 times more toxic than carbon monoxide is: (126) [4.3.11]

A. chlorine
B. phosphene
C. nitrous oxide
D. hydrogen cyanide

D. hydrogen cyanide

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In a fire, gases will always: (126) [4.3.11]

A. remain calm and move very little.
B. move in random, unpredictable paths.
C. move from areas of higher pressure to areas of lower pressure.
D. move from areas of lower pressure to areas of higher pressure.

C. move from areas of higher pressure to areas of lower pressure.

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Which term describes the measure of energy flowing to an area or object? (127) [4.3.12]

A. Heat flux
B. Temperature
C. Combustion rate
D. Heat dissipation rate

A. Heat flux

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Two surfaces rubbing together creates friction, which generates: (130) [4.3.12]

A. kinetic energy
B. chemical energy
C. electrical energy
D. mechanical energy

D. mechanical energy

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Which material is least able to conduct heat? (132) [4.3.12]

A. Air
B. Steel
C. Copper
D. Concrete

A. Air

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Which method of heat transfer occurs when energy is transferred by the circulation or movement of a liquid or gas? (132) [4.3.12]

A. Pyrolysis
B. Radiation
C. Conduction
D. Convection

C. Conduction

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When a fire transmits energy to an object some distance away from it through electromagnetic waves, this is an example of: (132) [4.3.12]

A. radiation
B. conduction
C. convection
D. flame impingement

A. radiation

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An example of an inorganic fuel is: (135) [4.3.10]

A. coal
B. gasoline
C. hydrogen
D. wood

D. wood

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For flaming combustion to occur, fuels must be: (137) [4.3.10, 4.3.11]

A. in the liquid state
B. in the gaseous state
C. a solid with a low surface-to-mass ratio
D. a solid with a high surface-to-mass ratio
Answer: B

B. in the gaseous state

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In order to burn, liquid fuels must: (138) [4.3.10, 4.3.11]

A. pyrolyze
B. vaporize
C. have a specific gravity less than one
D. have a specific gravity greater than one

B. vaporize

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The temperature at which a piloted ignition of sufficient vapors will begin a sustained combustion reaction is the: (139) [4.3.11]

A. fire point
B. flash point
C. flame point
D. ignition point

A. fire point

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The term that describes the extent to which a fuel substance will mix with water is: (139) [4.3.10]

A. solubility
B. miscibility
C. solvability
D. dissolvability

A. solubility

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What is the term used to describe flammable liquids that will mix readily with water? (139) [4.3.10]

A. Polar solvents
B. Similar solvents
C. Reactive solvents
D. Disparate solvents

A. Polar solvents

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Pyrolysis occurs when a: (139) [4.3.11]

A. fuel in any state reaches its autoignition temperature.
B. miscible material mixes with a polar solvent and ignites.
C. combustible gas is cooled to the point where it cannot ignite.
D. solid fuel is heated sufficiently so that it decomposes and gives off combustible vapors.

D. solid fuel is heated sufficiently so that it decomposes and gives off combustible vapors.

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What is the primary consideration when determining how easily solid fuels ignite? (140) [4.3.10, 4.3.11]

A. Size of the fuel
B. Mass of the fuel
C. Shape of the fuel
D. Surface-to-mass ratio of the fuel

D. Surface-to-mass ratio of the fuel

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Air normally consists of ___ percent oxygen. (140) [4.3.11]

A. 13
B. 21
C. 25
D. 35

B. 21

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How would an atmosphere that has a low oxygen concentration of 15 percent affect combustion of materials? (141) [4.3.11]

A. Materials could still ignite and burn at regular temperatures.
B. Materials would momentarily ignite, but then self-extinguish very quickly.
C. The atmosphere would require more oxygen in order for any solid or liquid material to burn.
D. The ambient temperature would have to be very high in order for materials to ignite and burn.

A. Materials could still ignite and burn at regular temperatures.

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25. Which is a true statement about fires in an oxygen-enriched atmosphere? (143) [4.3.11] A. Fires in oxygen-enriched atmospheres are easier to extinguish than fires at lower oxygen levels. B. Petroleum-based materials will self-extinguish when ignited in an oxygen-enriched atmosphere. C. Materials that burn at normal oxygen levels will burn less intensely in an oxygen-enriched atmosphere. D. Materials that burn at normal oxygen levels will burn more intensely in an oxygen-enriched atmosphere.

D. Materials that burn at normal oxygen levels will burn more intensely in an oxygen-enriched atmosphere.

What is the concentration limit above which the gas or vapor is said to be too rich to burn? (143) [4.3.11] A. Least explosive (flammable) limit (LEL) B. Over explosive (flammable) limit (OEL) C. Lower explosive (flammable) limit (LEL) D. Upper explosive (flammable) limit (UEL)

D. Upper explosive (flammable) limit (UEL)

Flaming combustion is one example of a: (144) [4.3.11] A. fusion reaction. B. fission reaction. C. chemical chain reaction. D. photosynthesis reaction.

C. chemical chain reaction.

What occurs when an extinguishing agent interferes with the chemical chain reaction and stops combustion? (144) [4.3.11] A. Sublimation B. Autoignition C. Chemical flame inhibition D. Unstable oxidation reaction

C. Chemical flame inhibition

When sufficient oxygen is available for flaming combustion, a fire is said to be: (145) [4.3.11] A. fuel-limited. B. heat-limited. C. ventilation-limited. D. combustion-limited.

A. fuel-limited.

In a ventilation-limited fire, the heat and growth is limited by the: (145) [4.3.11] A. amount of oxygen available to the fire. B. fuel that is available in the fire compartment. C. fuel that is available in adjacent compartments. D. amount of carbon monoxide available to the fire.

A. amount of oxygen available to the fire. ✨You work so hard. You're so deserving of all the success coming your way.✨

Which stage of fire development occurs when the fire is small and confined to the fuel first ignited? (146) [4.3.11] A. Decay B. Growth C. Incipient D. Fully developed

C. Incipient

At the end of the growth stage, ventilation-limited fires tend to enter an early state of decay because there is no longer enough available ___ for the fire to become fully developed. (146) [4.3.11] A. fuel B. heat C. space D. oxygen

D. oxygen

In the incipient stage of fire growth, the (146) [4.3.11] A. fire can always be characterized as ventilation-limited. B. fire grows rapidly and moves to other compartments. C. fire can safely be extinguished using a portable fire extinguisher. D. compartment provides adequate oxygen and development depends on the fuel.

D. compartment provides adequate oxygen and development depends on the fuel.

When a fire draws in air from around it, this is known as: (148) [4.3.11] A. transition. B. absorption. C. entrainment. D. embodiment.

C. entrainment.

The area surrounding a heat source in which there is sufficient air available to feed a fire is the ___ zone. (149) [4.3.11] A. fire B. burning C. combustion D. entrainment

C. combustion

The tendency of gases to form into layers according to temperature, gas density, and pressure is thermal: (150) [4.3.11, 4.3.12] A. plying. B. layering. C. sheeting. D. lamination.

B. layering.

The appearance of isolated or intermittent flames moving through the hot gas layer in a compartment can indicate that: (150) [4.3.11, 4.3.12] A. flashover is about to occur. B. the fire is entering the growth stage. C. the fire is becoming ventilation-limited. D. the addition of oxygen to the compartment will force the fire into decay.

A. flashover is about to occur.

The interface between the hot gas layer and cooler layer of air in a compartment fire is known as the: (150) [4.3.11, 4.3.12] A. neutral plane. B. neutral balance level. C. neutral pressure zone. D. neutral pressure interface.

A. neutral plane.

While a closed compartment reduces the heat release rate of a fire, fuel may continue to pyrolyze, which: (151) [4.3.11] A. creates fuel-rich smoke. B. decreases smoke production. C. gradually increases the heat release rate. D. generates smoke that is too rich to ignite.

A. creates fuel-rich smoke.

In ventilation-limited fires any kind of ventilation will: (152) [4.3.11] A. cause the fire to decay. B. cause the fire to smolder. C. increase the combustion rate. D. decrease the heat release rate.

C. increase the combustion rate.

As flashover occurs, the: (153) [4.3.11] A. fire’s heat release rate begins to decrease. B. thermal layering of gases becomes more visibly distinct. C. combustible materials and gases in the compartment ignite almost simultaneously. D. use of coordinated tactical ventilation will create an environment that is tenable for firefighters. Answer: C

C. combustible materials and gases in the compartment ignite almost simultaneously.

When unburned fire gases that have accumulated at the top of a compartment ignite and flames propagate through the hot gas layer or across the ceiling, this is called: (154) [4.3.11] A. rollover. B. flashover. C. backdraft. D. smoke explosion.

A. rollover.

In order for a fire to progress to flashover, there must be sufficient heat release rate and: (154-155) [4.3.11] A. ventilation. B. a high neutral plane. C. a sealed compartment. D. vertical fuel configuration.

A. ventilation.

What is an indicator that flashover is about to occur in a compartment fire? (155) [4.3.11, 4.3.12] A. Free burning flames B. Lowering of the neutral plane C. Temperatures decreasing rapidly D. Presence of products of combustion

B. Lowering of the neutral plane

A ventilation-limited compartment fire can produce a large volume of flammable smoke because: (156) [4.3.11] A. accelerated oxidation. B. incomplete combustion. C. lack of a source of ignition. D. an excess of oxygen in the air.

B. incomplete combustion.

What can lead to backdraft? (156) [4.3.11] A. Ventilating a space filled with fuel-rich smoke B. Adding oxygen to a compartment that is about to flashover C. Allowing a fuel-limited fire to burn itself out without any intervention D. Closing the door to a compartment with a ventilation-limited fire inside

A. Ventilating a space filled with fuel-rich smoke

Anytime a compartment or space contains hot combustion products, firefighters must consider the potential for backdraft before: (157) [4.3.11, 4.3.12] A. positioning apparatus. B. performing salvage and overhaul. C. discharging water into the compartment. D. creating any openings to the compartment.

D. creating any openings to the compartment.

The fully developed stage occurs when the heat release rate of the fire has: (157) [4.3.11] A. stabilized. B. begun to rise. C. reached its peak. D. begun to decline.

C. reached its peak.

The most effective method of increasing the heat release rate in a fuel-limited, fully developed fire is to: (157) [4.3.11] A. provide more oxygen. B. enlarge the fire compartment. C. change the configuration of the existing fuel.

A. provide more oxygen.

Adding ventilation points to a compartment fire that is ventilation-limited will: (158) [4.3.11] A. result in immediate flashover. B. have limited impact on fire growth. C. add oxygen that will allow the fire to grow. D. result in a more tenable atmosphere for firefighters.

C. add oxygen that will allow the fire to grow.

Which statement about a ventilation-limited compartment fire is true? (158) [4.3.11] A. Ventilation-limited, fully developed fires present a little risk to firefighters. B. The safest tactic is to create as many openings as possible in order to reduce fire growth. C. In order to transition the fire to fuel-limited, water should be applied from the outside through a ventilation opening. D. It is not possible to make enough openings in a compartment to transition a fire from ventilation-limited to fuel-limited conditions.

D. It is not possible to make enough openings in a compartment to transition a fire from ventilation-limited to fuel-limited conditions.

When a fire runs out of available fuel or oxygen, it is: (159) [4.3.11] A. in the decay stage. B. unable to grow anymore. C. in the fully developed stage. D. no longer able to cause harm to firefighters.

A. in the decay stage.

The ___ in a structure fire consists of ambient air flow in and hot gases flowing out the exhaust. (161) [4.3.11] A. flow path B. pressurization source C. bidirectional flow D. stack effect

A. flow path

Which factor affects a flow path’s effectiveness to transport ambient air throughout the compartment? (162) [4.3.11] A. Size of ventilation openings B. Type of fuel involved in the fire C. Amount of heat being generated D. Stage in which the fire is burning

A. Size of ventilation openings

Which statement concerning flow path is true? (162) [4.3.11] A. The least dangerous area of the flow path is near the exhaust. B. Air always moves along the flow path from areas of low pressure to areas of high pressure. C. Air always moves along the flow path from areas of high pressure to areas of low pressure. D. When firefighters create openings for ventilation or to make entry, they establish new flow paths.

D. When firefighters create openings for ventilation or to make entry, they establish new flow paths.

How can wind affect fire development in a structure fire? (164) [4.3.11] A. It can transition the fire from fuel-limited to ventilation-limited. B. Wind will have no effect on how a fire develops in a structure fire. C. It can cool the temperatures and make the atmosphere safer for crews working inside. D. It can create pressure differences that cause windows to fail and provide oxygen to the fire.

D. It can create pressure differences that cause windows to fail and provide oxygen to the fire.

A structure’s fuel load is made up of: (167) [4.3.10, 4.3.11] A. the amount of extinguishing agent required to put out the fire in the structure. B. all combustible materials inside, including any flammable construction materials. C. the structure’s furnishings, but not the construction materials used to build the structure. D. any combustible material within the incident perimeter, including exposure buildings.

B. all combustible materials inside, including any flammable construction materials.

How fire is likely to react and spread within a structure: (168) [4.3.10, 4.3.11] A. A fire in a structure with a high fuel load will have a lower heat release rate. B. A fire on the upper level of a building is more likely to travel downward to lower floors. C. A fire that starts in the basement of a building is less dangerous, because it can easily be contained before it spreads. D. A fire burning within hidden cavities in the building can make it more difficult to find and can increase the potential for collapse.

D. A fire burning within hidden cavities in the building can make it more difficult to find and can increase the potential for collapse.

Which statement about a compartment fire is true? (171) [4.3.10, 4.3.11] A. Given enough available fuel, fire will follow oxygen through a building along any available flow path. B. A closed door between two adjoining rooms will not slow the effect of a fire in one room on the adjoining room. C. Two rooms that a doorway connects are considered one compartment even if the door between them is closed. D. Firefighters should use doors to their advantage during interior operations, opening doors wherever possible to stop fire growth.

A. Given enough available fuel, fire will follow oxygen through a building along any available flow path.

Which feature of modern construction (homes built after 1990) poses problems for firefighters during extinguishment and ventilation? (172) [4.3.10, 4.3.11] A. Smaller houses on larger lots B. Windows that can be opened for ventilation C. Synthetic interior finishes and light wood components D. Smaller compartments and more compartments in one area

C. Synthetic interior finishes and light wood components ✨You're going to be a f*cking firefighter. Dude. Can we just let that sink in for a second!?✨

How can lightweight or engineered trusses react under fire conditions? (174) [4.3.11] A. They will fall much more slowly than heavy timber beams. B. They are not part of the fuel load, so they will not burn or fail. C. The trusses can fail without warning, even without flame contact. D. They will gradually lose strength and make a loud sound before failing.

C. The trusses can fail without warning, even without flame contact.

Which statement relating to buildings under construction, renovation, or demolition is true? (175) [4.3.10, 4.3.11] A. Because of restricted access, arson is rarely a factor at buildings undergoing demolition. B. Inoperative standpipes and sprinkler systems have become a contributing factor in fires in building under construction. C. The risk of fire is less for a building under construction than when completed because of the lack of combustible content. D. Hazardous situations are unlikely in occupied buildings undergoing renovation because conditions blocking escape of occupants or entry of firefighters are prohibited by code.

B. Inoperative standpipes and sprinkler systems have become a contributing factor in fires in building under construction.

Chapter 4 Flashcards

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