IFSTA Chapter 4 Quiz & Flashcards

Questions and Answers

Most building codes rate construction types according to:

The size of each compartment relative to the total square footage of the structure.

How long each construction type maintains its structural integrity over a certain period of time. (correct)

The ratio of the typical number of occupants to the number of egress points.

The size, type, and capability of fire suppression systems.

To ensure that the decay stage of a ventilation-limited fire is the fire's final stage, firefighters must provide a controlled transition of a fire in the decay stage from ventilation-limited to fuel-limited, by:

Carrying unburned fuel away from the compartment.

Protecting exposures until the fire consumes all available fuel.

Restricting ventilation until the heat transfers out of the compartment.

Cooling the hot fire gases before further ventilation occurs. (correct)

What provides the best indicators of structural integrity?

Year and method of construction

Occupancy classification

Occupant interview during the pre-incident survey

Information gathered at the scene (correct)

Fire spreading from a wall to a nearby couch due to radiant heat transfer is an example of:

Heat reflectivity Signup and view all the answers

Which element of the fire tetrahedron is included to explain flaming (gas-phase) combustion?

Chemical chain reaction Signup and view all the answers

When a structural member such as a window, roof, or doorway fails, introducing a new source of oxygen to a fire, _____ ventilation has occurred.

Unplanned Signup and view all the answers

The _____ stage of fire development occurs when the heat release rate of the fire has reached its peak.

Fully-developed Signup and view all the answers

The use of engineered or lightweight construction and trussed support systems pose a danger to firefighters because engineered trusses:

Can fail after 5 to 10 minutes of exposure to fire. Signup and view all the answers

A collapsed storage shed that is fully involved in flames would be an example of a:

Fully-developed fuel-limited fire. Signup and view all the answers

Where might firefighters be MOST likely to encounter inoperative standpipes and sprinkler systems?

Buildings under demolition Signup and view all the answers

When solid fuels are heated, they begin to _____ and release fuel gases and vapors.

Pyrolize Signup and view all the answers

Heat that is radiated to the insulating air layer between PPE and your body:

Can cause heat stress and failure of the PPE. Signup and view all the answers

How does a compartment fire affect pressure in and around gases in the compartment?

Heat from a fire increases the pressure of the surrounding gases. Signup and view all the answers

What factor helps determine the flow path in a structure fire?

The floor plan and openings within the structure Signup and view all the answers

Combustion can occur within a range of concentration of fuel vapor and air; this range is referred to as the:

Flammable (explosive) range. Signup and view all the answers

What occurs when a mixture of unburned fuel gases and oxygen come in contact with an ignition source?

Smoke explosion Signup and view all the answers

How does the self-sustained chemical reaction influence the oxidation reaction in flaming combustion?

Increases the speed of the oxidation reaction Signup and view all the answers

A compartment is any:

Open space with no complete fire barrier dividing it. Signup and view all the answers

An extinguishing agent, such as dry chemical or Halon-replacement agent, terminates the combustion reaction by:

Interfering with the chemical chain reaction. Signup and view all the answers

What is the cause of most fire deaths?

Exposure to toxic gases found in smoke and/or lack of oxygen Signup and view all the answers

A fuel's chemical content influences its heat release rate and its:

Heat of combustion. Signup and view all the answers

The minimum temperature at which a fuel in the air must be heated in order to start self-sustained combustion is known as the:

Autoignition temperature (AIT). Signup and view all the answers

What may occur if water is added to a burning liquid that is less dense than water?

The water may disperse the burning liquid instead of extinguishing it. Signup and view all the answers

Hydrogen cyanide (HCN) is a product of combustion that:

Targets the brain after being inhaled, ingested, or absorbed into the body. Signup and view all the answers

Which type of electrical heating occurs when the current flowing through a conductor exceeds its design limits?

Overcurrent or overload Signup and view all the answers

What is the most effective means of establishing awareness of hazards in commercial, industrial, and storage facilities with large fuel loads?

Performing and updating preincident surveys Signup and view all the answers

Which statement about the dangers of products of combustion is accurate?

Low oxygen concentrations alone can result in hypoxia or death. Signup and view all the answers

In a ventilation-limited compartment fire that has a large volume of flammable gases, opening a door or window could result in:

Backdraft Signup and view all the answers

In a compartment fire, smoke flashover indicators include rapidly increasing volume, turbulence, optical density, and:

Darkening color Signup and view all the answers

What causes flaming combustion to occur?

A gaseous fuel mixes with an adequate amount of oxygen and heats to ignition temperature. Signup and view all the answers

Which type of phenomenon occurs when the fire rapidly transitions from the growth stage to the fully developed stage?

Flashover Signup and view all the answers

A fire is said to be in the _____ stage when it runs out of either available fuel or available oxygen.

decay Signup and view all the answers

The transfer of heat through and between solids is known as:

Conduction Signup and view all the answers

Which product of combustion acts as a chemical asphyxiant by excluding oxygen from the blood, leading to hypoxia of the brain and tissues?

Carbon monoxide (CO) Signup and view all the answers

What is often the most readily available fuel source and significantly influences fire development in a compartment fire?

Contents within the structure Signup and view all the answers

What will a liquid with a specific gravity of less than one do when combined with water?

Float Signup and view all the answers

Which type of buildings are subject to rapid fire spread because many of the protective features such as gypsum wallboard and automatic fire suppression systems are not in place?

Buildings under construction Signup and view all the answers

What will establish new flow paths between the fire compartment and exterior vents of the building?

Firefighters advancing a hoseline through an open door or ventilating windows to make entry into a building Signup and view all the answers

Which statement about energy and combustion is accurate?

A fuel's potential energy releases during combustion and converts to kinetic energy. Signup and view all the answers

Which means of influencing fire dynamics is typically a tactic in wildland fires or liquid and gas fires?

Fuel removal Signup and view all the answers

Why must firefighters use tactics that control the oxygen available to the fire when they advance a hoseline through a door or ventilate windows?

To prevent unwanted fire spread Signup and view all the answers

Firefighters working in the exhaust portion of the flow path will:

Feel the increase in temperature as the velocity and/or turbulence increases. Signup and view all the answers

Using extinguishing agents other than water and foam to interrupt the combustion reaction is referred to as:

Chemical flame inhibition Signup and view all the answers

Which statement describes a fire in the incipient stage?

The temperature is only slightly above ambient in areas that the fire, plume, and ceiling jet directly affect. Signup and view all the answers

When a substance changes from one type of matter into another, such as two or more substances combining to form compounds, the substance undergoes a:

Chemical reaction Signup and view all the answers

In a compartment fire, the interface between the hot gas layers and cooler layer of air is commonly referred to as the:

Neutral plane Signup and view all the answers

By which mechanism of heat transfer does heat travel in a straight line at the speed of light, allowing heat to travel through vacuums and air spaces?

Radiation Signup and view all the answers

The minimum temperature at which a liquid gives off sufficient vapors to ignite, but not sustain combustion, is its:

Flash point Signup and view all the answers

Which action will transition a compartment fire in a modern structure from ventilation-limited to fuel-limited?

Extinguishing some of the fuel Signup and view all the answers

The flow path of a structure fire is comprised of two regions: the ambient air flow in and the:

Hot exhaust flow out Signup and view all the answers

Which statement BEST describes a fire in a large compartment or a compartment with a high ceiling?

In structures with high ceilings, a large volume of hot smoke and fire gases can accumulate at the ceiling level, while conditions at floor level remain relatively unchanged. Signup and view all the answers

Which statement about ventilation and wind considerations is MOST accurate?

Wind can increase the pressure inside the structure, driving smoke and flames into unburned portions of the structure and onto advancing firefighters. Signup and view all the answers

What is the likely result if additional air is allowed into an already-ventilated compartment fire?

Higher peak heat release rate Signup and view all the answers

Materials that burn at normal oxygen levels will burn more intensely in _____ atmospheres.

Oxygen-enriched Signup and view all the answers

Gaseous fuels can be the most dangerous of all fuel types because they:

Are already in the physical state required for ignition. Signup and view all the answers

During the _____ stage of fire development, the three elements of the fire triangle come together and the combustion process begins.

Incipient Signup and view all the answers

Which is an indicator for potential backdraft?

Pulsing smoke movement around small openings in the building Signup and view all the answers

What is the MOST common source of heat in combustion reactions?

Chemical energy Signup and view all the answers

In addition to structural members, what can be a significant factor influencing fire spread and loss of lives in fires?

Combustible interior finishes and furnishings Signup and view all the answers

Which statement describes the factor that MOST influences compartment fire development?

Whether the fire is fuel-limited or ventilation-limited Signup and view all the answers

Which measurement is often used to measure how long PPE will protect a firefighter in an interior fire environment?

Heat flux to the PPE Signup and view all the answers

In most compartment fires, the energy release in fire is directly proportional to the:

Amount of oxygen available for combustion Signup and view all the answers

Sawdust ignites more easily than a log because the sawdust has a higher:

Surface-to-mass ratio Signup and view all the answers

Fires involve a heat producing chemical reaction between fuel and:

An oxidizer Signup and view all the answers

What occurs when a gas is compressed?

Heat is generated Signup and view all the answers

Which heat transfer mechanism is dependent on several factors including the turbulence and velocity of moving gases?

Convection Signup and view all the answers

In the fire environment, convection usually involves the transfer of heat through:

The movement of hot smoke and fire gases Signup and view all the answers

What will occur if firefighters begin an attack on a ventilation-limited structure fire with ventilation alone?

The fire's heat release rate and spread will progressively increase as additional vents are made Signup and view all the answers

What occurs during flashover?

The volume of burning gases can increase to fill the room's entire volume and extend out of any openings from the room. Signup and view all the answers

What is the measurement of the average kinetic energy in the particles of a sample of matter?

Temperature Signup and view all the answers

What construction features tend to contain fires for a longer period of time, thus creating fuel-rich, ventilation-limited environments?

Energy-efficient designs Signup and view all the answers

What occurs when a mixture of fuel and oxygen encounters an external heat source with sufficient heat or thermal energy to start the combustion reaction?

Piloted ignition Signup and view all the answers

Fires develop through four stages: incipient, growth, _____, and decay.

Fully-developed Signup and view all the answers

What may occur in an oxidation reaction when the heat generated exceeds the heat being lost?

Spontaneous ignition Signup and view all the answers

Observed from the exterior, a high neutral plane may indicate that the fire is in the early stages of development, or could indicate:

A fire above your level. Signup and view all the answers

Study Notes

Electrical Heating

Overcurrent or overload happens when current exceeds design limits in a conductor.

Hazard Awareness

Preincident surveys are crucial for identifying hazards in facilities with large fuel loads.

Products of Combustion

Low oxygen concentrations can cause hypoxia, leading to death.

Ventilation-Limited Fires

Opening a door or window in a ventilation-limited fire may lead to backdraft, a sudden increase of flame.

Smoke Flashover Indicators

Indicators of smoke flashover include increasing volume, turbulence, optical density, and darkening color.

Flaming Combustion

Flaming combustion occurs when gaseous fuel mixes with sufficient oxygen and reaches ignition temperature.

Fire Growth Stages

Flashover is the rapid transition from the growth stage to fully developed stage of fire.

Fire Decay Stage

A fire is in the decay stage when it runs out of available fuel or oxygen.

Heat Transfer Mechanisms

Conduction refers to heat transfer through solids, while convection involves the movement of warm gases.

Chemical Asphyxiant

Carbon monoxide (CO) is a chemical asphyxiant that prevents oxygen from reaching the brain and tissues.

Fuel Sources in Fires

Contents within a structure often provide the most significant fuel source influencing fire development.

Liquid Specific Gravity

A liquid with a specific gravity less than one will float when placed in water.

Rapid Fire Spread Buildings

Buildings under construction are at higher risk for rapid fire spread due to fewer protective features.

New Flow Paths

Firefighters creating openings in a building establish new flow paths between compartments and outside.

Energy and Combustion

Combustion releases kinetic energy from a fuel's stored chemical potential energy.

Fire Dynamics in Wildland Fires

Fuel removal is a tactic commonly employed in wildland and liquid/gas fire scenarios.

Controlling Fire Spread

Firefighters must control oxygen availability when venting to prevent unwanted fire spread.

Flow Path Temperature

In the exhaust portion of a flow path, firefighters will sense rising temperatures due to increasing velocity and turbulence.

Interrupting Combustion

Chemical flame inhibition involves using agents other than water and foam to interrupt combustion processes.

Incipient Stage of Fire

In the incipient stage, temperatures are only slightly above ambient levels at affected fire areas.

Chemical Reaction Definition

A chemical reaction occurs when substances combine to form new compounds.

Neutral Plane Definition

The interface between hot gas layers and cooler air is known as the neutral plane in fire dynamics.

Radiation Mechanism

Radiation allows heat to travel through vacuums and air spaces without direct contact.

Flash Point

The flash point is the minimum temperature at which a liquid can emit sufficient vapors to ignite.

Transitioning Fire Dynamics

Extinguishing some fuel can change a compartment fire from ventilation-limited to fuel-limited.

Flow Path Characteristics

The flow path consists of ambient air flowing in and hot exhaust gases flowing out.

Compartment Fire Development

Large compartments can alter fire behavior; gases can accumulate at ceiling level, affecting conditions at the floor.

Wind and Ventilation

Wind can increase pressure within a structure, potentially forcing smoke and flames toward unburned areas.

Compartment Fire Changes

Introducing fresh air into a ventilated compartment can increase the fire's heat release rate.

Combustion Intensification

Materials burn more intensely in oxygen-enriched atmospheres.

Gaseous Fuels

Gaseous fuels pose a significant risk due to their state being primed for ignition.

Stages of Fire Development

The four stages of fire include incipient, growth, fully-developed, and decay.

Backdraft Risk Indicators

Pulsing smoke movement in small openings can signal potential backdraft conditions.

Heat Source in Combustion

Chemical energy is the most common source of heat in combustion reactions.

Fire Spread Factors

Combustible interior finishes significantly contribute to fire spread and loss of life during incidents.

Fuel-Limited vs. Ventilation-Limited Fires

Fire behavior is highly influenced by whether the fire is fuel-limited or ventilation-limited.

PPE Heat Protection Measurement

Heat flux to PPE is measured to determine the protection duration for firefighters in interior fire conditions.

Oxygen Availability

The amount of oxygen available directly correlates with energy release in fire scenarios.

Sawdust Ignition

Sawdust ignites more easily than less fragmented timber due to its higher surface-to-mass ratio.

Oxidizer in Fire Reactions

Fires result from the chemical reaction between fuel and an oxidizer.

Gas Compression

Compressing a gas generates heat, raising its temperature.

Convection Factors

Convection heat transfer is affected by factors like turbulence and velocity of gases.

Fire Environment Dynamics

Inenviroment, convection generally involves the transfer of heat from moving hot gases.

Ventilation in Structure Fires

Ventilating a structure fire can lead to increased heat release rates and fire spread if mismanaged.

Flashover Definition

Flashover occurs when burning gases fill the entire compartment volume, extending beyond openings.

Kinetic Energy Measurement

Temperature measures the average kinetic energy of particles in a substance.

Construction Feature Impacts

Energy-efficient designs can lead to prolonged fire containment, fostering dangerous fire conditions.

Piloted Ignition Process

Piloted ignition occurs when a fuel-oxygen mixture encounters sufficient external heat to initiate combustion.

Stages Summary

Fire progression involves four stages: incipient, growth, fully-developed, and decay.

Oxidation Reaction Outcomes

Excess heat generation in an oxidation reaction can lead to spontaneous ignition.

High Neutral Plane Indicator

A high neutral plane may indicate a developing fire in upper areas of a structure.

Building Code Ratings

Construction types are rated by their ability to maintain structural integrity over time.

Managing Decay Stage Fires

Proper cooling of hot gases is critical to ensuring the fire remains in a controlled decay stage.

Structural Integrity Indicators

Information gathered from the scene gives the best indicators of structural integrity during a fire.

Heat Transfer Examples

Radiant heat transfer can cause nearby materials to ignite, as seen with fire spreading from walls to furniture.

Chemical Chain Reaction Component

The fire tetrahedron includes the chemical chain reaction necessary for sustaining flaming combustion.

Unplanned Ventilation

Unplanned ventilation occurs when openings or failures inadvertently introduce fresh oxygen to an existing fire.### Fire Stages and Development
The fully-developed stage of fire development occurs when the heat release rate has peaked.
A collapsed storage shed engulfed in flames exemplifies a fully-developed fuel-limited fire.

Structural Hazards

Engineered trusses can fail in 5 to 10 minutes of exposure to fire, posing risks for firefighters.
Inoperative standpipes and sprinkler systems are more likely found in buildings under demolition.

Fuel Behavior and Combustion

Solid fuels pyrolize when heated, releasing fuel gases and vapors.
The flammable (explosive) range defines the concentration limits of fuel vapor and air for combustion.
Smoke explosions occur when unburned fuel gases mix with oxygen and contact an ignition source.

Fire Dynamics

A fire increases the pressure of surrounding gases in a compartment.
The floor plan and openings within a structure significantly influence the flow path in a fire.
The self-sustained chemical reaction in flaming combustion speeds up the oxidation reaction.

Extinguishing Methods

An extinguishing agent disrupts the chemical chain reaction to terminate combustion.
Adding water to burning liquids that are less dense can cause the water to disperse the fuel instead of extinguishing it.

Toxicity and Hazards

Most fire-related deaths result from exposure to toxic gases in smoke, notably due to the lack of oxygen.
Hydrogen cyanide (HCN) is a highly toxic product of combustion that targets the brain.

Fire Behavior and Safety

A fuel's chemical composition impacts its heat release rate and heat of combustion.
Autoignition temperature (AIT) is the minimum temperature required to initiate self-sustained combustion in the presence of air.

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Test your knowledge with these flashcards based on Chapter 4 of the IFSTA materials. This quiz covers important concepts such as electrical heating types and hazard awareness in facilities. Perfect for those studying for firefighting and safety certifications.

IFSTA Chapter 4 Flashcards