Podcast
Questions and Answers
What is the primary function of a heat sink in relation to smoke production?
What is the primary function of a heat sink in relation to smoke production?
- To ignite materials easily
- To generate more smoke in a fire
- To decrease the temperature of burning materials
- To transfer heat from burning materials (correct)
Which component of smoke is characterized by high surface-to-mass and easy ignition properties?
Which component of smoke is characterized by high surface-to-mass and easy ignition properties?
- Gases
- Ash
- Particulates (correct)
- Aerosols
At what temperature can hydrocarbons in smoke self-ignite?
At what temperature can hydrocarbons in smoke self-ignite?
- $300°F (149°C)$
- $700°F (371°C)$
- $200°F (93°C)$
- $450°F (232°C)$ (correct)
What is the main component of smoke that is carbon-based and is a prevalent solid?
What is the main component of smoke that is carbon-based and is a prevalent solid?
Which chemical compound found in smoke can affect fire behavior and poses a danger to health?
Which chemical compound found in smoke can affect fire behavior and poses a danger to health?
Why is the use of SCBA and PPE emphasized when dealing with smoke?
Why is the use of SCBA and PPE emphasized when dealing with smoke?
What phase of fire growth model is characterized by a compartmentalized fire condition with open flaming decreasing due to limited available air?
What phase of fire growth model is characterized by a compartmentalized fire condition with open flaming decreasing due to limited available air?
Which of the following is NOT considered a hostile fire event?
Which of the following is NOT considered a hostile fire event?
In which phase of fire growth does pyrolysis begin and smoke production becomes abundant?
In which phase of fire growth does pyrolysis begin and smoke production becomes abundant?
What are the warning signs of a backdraft event in a closed pressurized box?
What are the warning signs of a backdraft event in a closed pressurized box?
What is the rapid fire growth phenomenon that occurs when combustion air is reintroduced into a ventilation-controlled fire?
What is the rapid fire growth phenomenon that occurs when combustion air is reintroduced into a ventilation-controlled fire?
'Room visibility is still good at lower levels, and smoke from the flames begins to accumulate at the ceiling.' Which phase of fire growth does this statement describe?
'Room visibility is still good at lower levels, and smoke from the flames begins to accumulate at the ceiling.' Which phase of fire growth does this statement describe?
'Dense smoke appears to have totally filled a building, floor to ceiling.' What hostile fire event does this scenario suggest?
'Dense smoke appears to have totally filled a building, floor to ceiling.' What hostile fire event does this scenario suggest?
'Turbulent smoke flow that has filled a compartment' is characteristic of which hostile fire event?
'Turbulent smoke flow that has filled a compartment' is characteristic of which hostile fire event?
'Yellowish-gray smoke emitting from cracks and seams.' What hostile fire event does this statement point towards?
'Yellowish-gray smoke emitting from cracks and seams.' What hostile fire event does this statement point towards?
'Smoke that rapidly speeds up when an exterior door is opened.' What stage of hostile fire events might this describe?
'Smoke that rapidly speeds up when an exterior door is opened.' What stage of hostile fire events might this describe?
What is the flammable range of smoke in air?
What is the flammable range of smoke in air?
What triggers can cause accumulated smoke to ignite?
What triggers can cause accumulated smoke to ignite?
How does the ignition of accumulated smoke change the fire spread dynamics?
How does the ignition of accumulated smoke change the fire spread dynamics?
What is a key factor influencing compartmentalized fire growth?
What is a key factor influencing compartmentalized fire growth?
Why is understanding smoke considered important in firefighting?
Why is understanding smoke considered important in firefighting?
How did NIST and UL secure federal grant monies in the late 1990s?
How did NIST and UL secure federal grant monies in the late 1990s?
What was identified as inadequate for certain fires in relatively small buildings?
What was identified as inadequate for certain fires in relatively small buildings?
When do smoke gases need only a proper air mix and a sudden spark or flame to ignite?
When do smoke gases need only a proper air mix and a sudden spark or flame to ignite?
What does brown smoke from structural spaces, such as OSB and LVL, indicate?
What does brown smoke from structural spaces, such as OSB and LVL, indicate?
What does white smoke that is fast-moving and dirty indicate in a fire incident?
What does white smoke that is fast-moving and dirty indicate in a fire incident?
What does the term 'black fire' refer to in relation to smoke?
What does the term 'black fire' refer to in relation to smoke?
What is the indication of white smoke being all black eventually?
What is the indication of white smoke being all black eventually?
How does thermal balance influence the appearance of smoke in a fire incident?
How does thermal balance influence the appearance of smoke in a fire incident?
What does high-velocity, very thin black smoke indicate in a fire?
What does high-velocity, very thin black smoke indicate in a fire?
Why is it important to remove cancer-causing substances from Personal Protective Equipment (PPE) surfaces?
Why is it important to remove cancer-causing substances from Personal Protective Equipment (PPE) surfaces?
What does the thickness of black smoke in a compartment indicate about life sustainability?
What does the thickness of black smoke in a compartment indicate about life sustainability?
What is indicated by fast-moving, dirty white smoke in terms of fire intensity?
What is indicated by fast-moving, dirty white smoke in terms of fire intensity?
Why do most fire service curriculums consider teaching about smoke color misleading?
Why do most fire service curriculums consider teaching about smoke color misleading?
What is the defining characteristic of 'black fire'?
What is the defining characteristic of 'black fire'?
During which fire growth phenomenon does combustion air reintroduction lead to smoke flame-over?
During which fire growth phenomenon does combustion air reintroduction lead to smoke flame-over?
What defines a 'hostile fire event' that includes flame-over?
What defines a 'hostile fire event' that includes flame-over?
What characterizes 'intermittent ignition' in fire behavior terms?
What characterizes 'intermittent ignition' in fire behavior terms?
Which fire behavior phenomenon involves a spark or flame igniting a pocket of smoke rapidly?
Which fire behavior phenomenon involves a spark or flame igniting a pocket of smoke rapidly?
What is the primary function of a flow path in fire behavior?
What is the primary function of a flow path in fire behavior?
What are the four distinctive characteristics of smoke mentioned in the text?
What are the four distinctive characteristics of smoke mentioned in the text?
Which characteristic of smoke can indicate the amount of fuels off-gassing in a space?
Which characteristic of smoke can indicate the amount of fuels off-gassing in a space?
What does backdraft refer to in relation to a fire event?
What does backdraft refer to in relation to a fire event?
What warning sign for hostile fire events is considered dangerously late according to the text?
What warning sign for hostile fire events is considered dangerously late according to the text?
Which type of smoke movement warrants more attention due to being caused by convection heat?
Which type of smoke movement warrants more attention due to being caused by convection heat?
What does laminar smoke flow indicate about a fire?
What does laminar smoke flow indicate about a fire?
Which characteristic of smoke can help determine the location of a fire by comparing its velocity at different openings?
Which characteristic of smoke can help determine the location of a fire by comparing its velocity at different openings?
What does low-lying smoke typically indicate in a building fire?
What does low-lying smoke typically indicate in a building fire?
What can light, thin smoke showing from more than one opening of a very large building indicate?
What can light, thin smoke showing from more than one opening of a very large building indicate?
What does it indicate if smoke becomes darker and thicker when ventilation fans are being used?
What does it indicate if smoke becomes darker and thicker when ventilation fans are being used?
Why did Positive-Pressure Attack (PPA) gain popularity for fire attack?
Why did Positive-Pressure Attack (PPA) gain popularity for fire attack?
What are some warnings to shut down Positive-Pressure Attack (PPA) tactics?
What are some warnings to shut down Positive-Pressure Attack (PPA) tactics?
What do turbulent smoke that fills a box and thick, black, fast smoke typically indicate, respectively?
What do turbulent smoke that fills a box and thick, black, fast smoke typically indicate, respectively?
What is the importance of practicing the skill of reading smoke?
What is the importance of practicing the skill of reading smoke?
What does thin, black, fast smoke typically indicate in a fire scenario?
What does thin, black, fast smoke typically indicate in a fire scenario?
Why should ISOs be well-versed in Positive-Pressure Attack (PPA) tactics?
Why should ISOs be well-versed in Positive-Pressure Attack (PPA) tactics?
What warning sign does brown smoke typically indicate during a firefighting operation?
What warning sign does brown smoke typically indicate during a firefighting operation?
What is the primary importance of open flaming in a building fire according to the text?
What is the primary importance of open flaming in a building fire according to the text?
What triggers can cause accumulated smoke to ignite according to the text?
What triggers can cause accumulated smoke to ignite according to the text?
What happens when smoke gases reach their ignition temperature in a ventilation-limited fire?
What happens when smoke gases reach their ignition temperature in a ventilation-limited fire?
What change in fire spread dynamics occurs when accumulated smoke ignites?
What change in fire spread dynamics occurs when accumulated smoke ignites?
What was identified as inadequate for certain fires in relatively small buildings according to the text?
What was identified as inadequate for certain fires in relatively small buildings according to the text?
What is the collective flammable range of smoke in air according to the text?
What is the collective flammable range of smoke in air according to the text?
What ultimately dictates fire behavior according to the text?
What ultimately dictates fire behavior according to the text?
"Traditional teaching has described a four-phase growth model for a building fire." How many phases does the text suggest for interior building fires?
"Traditional teaching has described a four-phase growth model for a building fire." How many phases does the text suggest for interior building fires?
"The size, type, quantity, and continuity of the fire load" are factors influencing which of the following aspects according to the text?
"The size, type, quantity, and continuity of the fire load" are factors influencing which of the following aspects according to the text?
"Watching smoke flow can help understand what is about to happen." According to the text, what does smoke represent as a form of communication?
"Watching smoke flow can help understand what is about to happen." According to the text, what does smoke represent as a form of communication?
What is the main difference between soot and ash in smoke?
What is the main difference between soot and ash in smoke?
What is the primary reason why hydrocarbons in smoke are considered dangerous?
What is the primary reason why hydrocarbons in smoke are considered dangerous?
Why is pyrolysis important in understanding smoke's behavior?
Why is pyrolysis important in understanding smoke's behavior?
Which of the following statements about fire gases in smoke is true?
Which of the following statements about fire gases in smoke is true?
How do aerosols contribute to the composition of smoke at a structure fire?
How do aerosols contribute to the composition of smoke at a structure fire?
What characteristic of smoke contributes to causing a fire to become ventilation-limited?
What characteristic of smoke contributes to causing a fire to become ventilation-limited?
What phase of fire growth is characterized by a compartmentalized fire condition where open flaming decreases due to limited available air?
What phase of fire growth is characterized by a compartmentalized fire condition where open flaming decreases due to limited available air?
Which hostile fire event involves a sudden and rapid increase in pressure due to the ignition of smoke?
Which hostile fire event involves a sudden and rapid increase in pressure due to the ignition of smoke?
What signifies the beginning of pyrolysis and abundant smoke production in a fire incident?
What signifies the beginning of pyrolysis and abundant smoke production in a fire incident?
What is a common warning sign for hostile fire events that can be considered dangerously late according to the text?
What is a common warning sign for hostile fire events that can be considered dangerously late according to the text?
'Room visibility is still good at lower levels, and smoke from the flames begins to accumulate at the ceiling.' Which phase of fire growth does this statement describe?
'Room visibility is still good at lower levels, and smoke from the flames begins to accumulate at the ceiling.' Which phase of fire growth does this statement describe?
'Dense smoke appears to have totally filled a building, floor to ceiling.' What hostile fire event does this scenario suggest?
'Dense smoke appears to have totally filled a building, floor to ceiling.' What hostile fire event does this scenario suggest?
'Yellowish-gray smoke emitting from cracks and seams.' What hostile fire event does this statement point towards?
'Yellowish-gray smoke emitting from cracks and seams.' What hostile fire event does this statement point towards?
'Smoke that is being trapped in a separate space above the fire.' What hostile fire event does this scenario suggest?
'Smoke that is being trapped in a separate space above the fire.' What hostile fire event does this scenario suggest?
'Increase in smoke speed. Ghosting. Laminar flow of smoke that becomes turbulent.' These signs are most likely indicative of:
'Increase in smoke speed. Ghosting. Laminar flow of smoke that becomes turbulent.' These signs are most likely indicative of:
What characterizes 'intermittent ignition' in fire behavior terms?
What characterizes 'intermittent ignition' in fire behavior terms?
What can a high volume of smoke indicate in a ventilation-limited environment?
What can a high volume of smoke indicate in a ventilation-limited environment?
In the context of smoke, what does a laminar flow typically indicate?
In the context of smoke, what does a laminar flow typically indicate?
What is the primary characteristic of heat-pushed smoke movements?
What is the primary characteristic of heat-pushed smoke movements?
What does turbulent smoke velocity that fills a compartment typically indicate?
What does turbulent smoke velocity that fills a compartment typically indicate?
What is the significance of comparing the velocity of smoke at different openings?
What is the significance of comparing the velocity of smoke at different openings?
Why should firefighters avoid crawling into a box filled with turbulent smoke?
Why should firefighters avoid crawling into a box filled with turbulent smoke?
What is indicated by thick, black smoke in a compartment?
What is indicated by thick, black smoke in a compartment?
What is the primary characteristic of black fire in a fire scenario?
What is the primary characteristic of black fire in a fire scenario?
Which fire behavior term describes the overhead smoke layer igniting and burning within a room or hallway?
Which fire behavior term describes the overhead smoke layer igniting and burning within a room or hallway?
What is the consequence of reintroducing combustion air into a ventilation-controlled fire?
What is the consequence of reintroducing combustion air into a ventilation-controlled fire?
Which fire behavior phenomenon involves a spark or flame igniting a pocket of smoke rapidly?
Which fire behavior phenomenon involves a spark or flame igniting a pocket of smoke rapidly?
What defines an avenue that heat, smoke, flames, and combustion air follow in a fire scenario?
What defines an avenue that heat, smoke, flames, and combustion air follow in a fire scenario?
What is pyrolysis primarily associated with in the context of fire behavior?
What is pyrolysis primarily associated with in the context of fire behavior?
What is the significance of smoke rising straight up without quickly cooling?
What is the significance of smoke rising straight up without quickly cooling?
When smoke becomes thicker and darker while ventilation fans are used, what does it suggest about the fan action?
When smoke becomes thicker and darker while ventilation fans are used, what does it suggest about the fan action?
In fire behavior terms, what does turbulent velocity of smoke indicate?
In fire behavior terms, what does turbulent velocity of smoke indicate?
What does dirty white smoke with velocity indicate in terms of fire intensity?
What does dirty white smoke with velocity indicate in terms of fire intensity?
What does thick, black, fast smoke typically indicate in a fire incident?
What does thick, black, fast smoke typically indicate in a fire incident?
If light, thin smoke is observed from more than one opening of a large building, what does it suggest?
If light, thin smoke is observed from more than one opening of a large building, what does it suggest?
What does low-volume white smoke from multiple locations of a large building indicate?
What does low-volume white smoke from multiple locations of a large building indicate?
When analyzing smoke observations in proportion to the building, why must the observer consider container size?
When analyzing smoke observations in proportion to the building, why must the observer consider container size?
What does white smoke indicate in terms of fire location?
What does white smoke indicate in terms of fire location?
What does the presence of fast-moving, dirty white smoke suggest?
What does the presence of fast-moving, dirty white smoke suggest?
What can brown smoke from structural spaces indicate?
What can brown smoke from structural spaces indicate?
How does smoke color change as materials are further heated?
How does smoke color change as materials are further heated?
What is the relation between smoke density and gross decontamination processes?
What is the relation between smoke density and gross decontamination processes?
What is the primary danger associated with smoke from a typical house fire?
What is the primary danger associated with smoke from a typical house fire?
What is the main reason why SCBA and PPE are crucial when dealing with smoke in fire suppression activities?
What is the main reason why SCBA and PPE are crucial when dealing with smoke in fire suppression activities?
Which statement best describes the process of pyrolysis in the context of fire behavior?
Which statement best describes the process of pyrolysis in the context of fire behavior?
What makes smoke displacement a critical factor that can affect fire behavior?
What makes smoke displacement a critical factor that can affect fire behavior?
Why are hydrocarbons in smoke specifically highlighted as self-igniting at low temperatures?
Why are hydrocarbons in smoke specifically highlighted as self-igniting at low temperatures?
What role do suspended or propelled liquids play in the composition of smoke at a structure fire?
What role do suspended or propelled liquids play in the composition of smoke at a structure fire?
What can initiate the ignition of smoke gases that are below their ignition temperature?
What can initiate the ignition of smoke gases that are below their ignition temperature?
Why is open flaming considered beneficial according to the text?
Why is open flaming considered beneficial according to the text?
What leads to an off-gassed smoke causing an underventilated condition in a ventilation-limited fire?
What leads to an off-gassed smoke causing an underventilated condition in a ventilation-limited fire?
What is the primary implication for fire behavior when accumulated smoke is pressurized within a room?
What is the primary implication for fire behavior when accumulated smoke is pressurized within a room?
Which factor influences compartmentalized fire growth according to the text?
Which factor influences compartmentalized fire growth according to the text?
Why was research into modern fire behavior initiated by NIST and UL, according to the text?
Why was research into modern fire behavior initiated by NIST and UL, according to the text?
What is the significance of smoke according to the text?
What is the significance of smoke according to the text?
When does smoke from low-mass materials reach ignition temperature without needing a spark or flame?
When does smoke from low-mass materials reach ignition temperature without needing a spark or flame?
What does white smoke emitted by solid materials when first heated mainly consist of?
What does white smoke emitted by solid materials when first heated mainly consist of?
What does brown smoke from structural spaces, like those containing OSB and LVL, warn of according to the text?
What does brown smoke from structural spaces, like those containing OSB and LVL, warn of according to the text?
What is the significance of black fire in a fire scenario?
What is the significance of black fire in a fire scenario?
What does fast-moving, dirty white smoke indicate about a fire's characteristics?
What does fast-moving, dirty white smoke indicate about a fire's characteristics?
How does smoke velocity assist in determining the distance to a fire?
How does smoke velocity assist in determining the distance to a fire?
What can be inferred when smoke is brown in color within a structure?
What can be inferred when smoke is brown in color within a structure?
How does smoke color change as materials are further heated according to the text?
How does smoke color change as materials are further heated according to the text?
What does high-velocity, very thin black smoke in a fire scenario indicate?
What does high-velocity, very thin black smoke in a fire scenario indicate?
What warning sign does thick, black, fast smoke typically provide in a fire incident?
What warning sign does thick, black, fast smoke typically provide in a fire incident?
What is the primary composition of white smoke emitted when solid materials are first heated according to the text?
What is the primary composition of white smoke emitted when solid materials are first heated according to the text?
What does laminar smoke flow typically indicate?
What does laminar smoke flow typically indicate?
What does heat-pushed smoke indicate?
What does heat-pushed smoke indicate?
What can a high volume of smoke indicate in a ventilation-limited environment?
What can a high volume of smoke indicate in a ventilation-limited environment?
What warning sign does black smoke in a compartment suggest?
What warning sign does black smoke in a compartment suggest?
In fire behavior terms, what is 'turbulent smoke velocity that fills a compartment' indicative of?
In fire behavior terms, what is 'turbulent smoke velocity that fills a compartment' indicative of?
What does the thickness of smoke typically indicate?
What does the thickness of smoke typically indicate?
'Ar (or smooth) flow of smoke near a fire indicates that the interior of the space is still absorbing heat or that the smoke has traveled some distance from the fire.' What does turbulent smoke typically indicate?
'Ar (or smooth) flow of smoke near a fire indicates that the interior of the space is still absorbing heat or that the smoke has traveled some distance from the fire.' What does turbulent smoke typically indicate?
'Turbulent vs Laminar Smoke Flow: Turbulent smoke velocity that has volume-filled a compartment indicates a flashover is imminent.' What does laminar smoke flow indicate?
'Turbulent vs Laminar Smoke Flow: Turbulent smoke velocity that has volume-filled a compartment indicates a flashover is imminent.' What does laminar smoke flow indicate?
What is the primary characteristic of a flame-over event in a fire scenario?
What is the primary characteristic of a flame-over event in a fire scenario?
During which fire growth phenomenon does smoke flame-over occur?
During which fire growth phenomenon does smoke flame-over occur?
What is pyrolysis primarily associated with in the context of fire behavior?
What is pyrolysis primarily associated with in the context of fire behavior?
Which component of smoke is characterized by high surface-to-mass and easy ignition properties?
Which component of smoke is characterized by high surface-to-mass and easy ignition properties?
What defines an avenue that heat, smoke, flames, and combustion air follow in a fire scenario?
What defines an avenue that heat, smoke, flames, and combustion air follow in a fire scenario?
What is the flammable range of smoke in air according to the text?
What is the flammable range of smoke in air according to the text?
What phase is characterized by a compartmentalized fire condition with open flaming decreasing due to smoke production?
What phase is characterized by a compartmentalized fire condition with open flaming decreasing due to smoke production?
What event is described as a sudden and rapid increase in pressure caused by the ignition of smoke?
What event is described as a sudden and rapid increase in pressure caused by the ignition of smoke?
Which fire behavior term refers to smoke that is rapidly heated, leading to a more sudden and violent event?
Which fire behavior term refers to smoke that is rapidly heated, leading to a more sudden and violent event?
What does the text suggest is the primary characteristic of 'black fire' in a fire scenario?
What does the text suggest is the primary characteristic of 'black fire' in a fire scenario?
What is indicated by laminar smoke flow transitioning into turbulent flow in a fire incident?
What is indicated by laminar smoke flow transitioning into turbulent flow in a fire incident?
'Yellowish-gray smoke emitting from cracks and seams.' What hostile fire event does this statement point towards?
'Yellowish-gray smoke emitting from cracks and seams.' What hostile fire event does this statement point towards?
'Dense smoke appears to have totally filled a building, floor to ceiling.' What hostile fire event does this scenario suggest?
'Dense smoke appears to have totally filled a building, floor to ceiling.' What hostile fire event does this scenario suggest?
What warning sign does 'laminar flow of smoke that is becoming turbulent' indicate during a firefighting scenario?
What warning sign does 'laminar flow of smoke that is becoming turbulent' indicate during a firefighting scenario?
What can be inferred from the presence of 'laminar flow of smoke that is becoming turbulent' in a building fire?
What can be inferred from the presence of 'laminar flow of smoke that is becoming turbulent' in a building fire?
What is characterized by an increase in smoke speed from tightened openings upon external entry during a hostile fire situation?
What is characterized by an increase in smoke speed from tightened openings upon external entry during a hostile fire situation?
What is a warning sign of an exceptionally hot fire, according to the text?
What is a warning sign of an exceptionally hot fire, according to the text?
What does light, thin smoke showing from multiple openings of a very large building indicate, as per the text?
What does light, thin smoke showing from multiple openings of a very large building indicate, as per the text?
What does thick, black, fast smoke typically suggest in a fire incident?
What does thick, black, fast smoke typically suggest in a fire incident?
What is a key factor for firefighters to consider when forced-ventilation tactics are being used, based on the text?
What is a key factor for firefighters to consider when forced-ventilation tactics are being used, based on the text?
What is the primary purpose of Positive-Pressure Attack (PPA) in firefighting, according to the text?
What is the primary purpose of Positive-Pressure Attack (PPA) in firefighting, according to the text?
What should firefighters look for as firefighting efforts progress during an incident, according to the text?
What should firefighters look for as firefighting efforts progress during an incident, according to the text?
What does turbulent smoke velocity filling a compartment typically indicate?
What does turbulent smoke velocity filling a compartment typically indicate?
What does the volume of smoke primarily indicate in terms of fire size?
What does the volume of smoke primarily indicate in terms of fire size?
What does light, thin smoke showing from more than one opening of a very large building typically suggest?
What does light, thin smoke showing from more than one opening of a very large building typically suggest?
What should ISOs look for when practicing reading smoke?
What should ISOs look for when practicing reading smoke?
Study Notes
Understanding Smoke in a Fire Incident
- Smoke can indicate the severity and location of a fire
- Different types of smoke have different characteristics and implications
- Factors influencing smoke behavior:
- Weather (cold air temperatures, humidity, wind)
- Thermal balance
- Container size
- Firefighting efforts
Interpreting Smoke Color
- White smoke: mostly moisture, can contain other gases and aerosols (ammonia, phenols)
- Black smoke: indicates high heat, can be a sign of impending flashover
- Brown smoke: indicates significant heat, can be a warning sign of impending collapse in engineered wood products
Smoke Velocity and Density
- Smoke velocity can help determine the distance to a fire
- Fast-moving, dirty white smoke indicates a hot fire exists
- Low-lying smoke can indicate a deep-seated fire or a fire not being controlled by a sprinkler system
Health and Safety Concerns
- Thick, black smoke reduces the chance of life sustainability due to smoke toxicology
- Smoke can contain cancer-causing substances that must be removed from PPE surfaces
Reading Smoke
- View the smoke and compare differences in attributes from each opening
- Analyze contributing factors affecting VVDC (volume, velocity, density, color)
- Determine the rate of change of each attribute
Positive-Pressure Attack (PPA) and Reading Smoke
- PPA is a specific tactical maneuver to improve smoke conditions and firefighter safety
- Monitor smoke conditions and firefighter actions to make informed decisions
- Warnings to shut down PPA tactics:
- No increase in smoke velocity at the exhaust opening
- Smoke VVDC leaving other portions of the building
- Fire discovered behind advancing firefighters
- Zero visibility and high heat reported by firefighters
Importance of Practicing the Skill of Reading Smoke
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Real-world experience is important for developing the skill of reading smoke
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Practice is necessary to improve the skill of reading smoke
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Use raw, fire-ground video footage for practice### Black Fire and Hostile Fire Events
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Black fire refers to high-volume, turbulent, and ultra-dense smoke that is a sign of impending autoignition and flashover.
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Hostile fire events include explosive growth phase, flashover, backdraft, smoke explosion, and flame-over, which can suddenly harm firefighters.
Definitions
- Pyrolysis: the chemical breakdown of compounds into other substances by heat alone.
- Smoke: the products of incomplete combustion and pyrolysis, including particles, aerosols, and fire gases that are toxic, flammable, and volatile.
Understanding Smoke Characteristics
- Smoke has four distinctive characteristics: volume, velocity, density, and color (VVDC).
- Volume of smoke can indicate the amount of fuels off-gassing in a given space.
- Smoke velocity is an indicator of pressure built up in the building.
- Smoke density refers to its thickness, which can indicate the amount of fuel in the smoke.
Hostile Fire Events
- Backdraft: an explosive event that occurs when air is suddenly reintroduced into a closed space filled with pressurized, ignition-temperature, and oxygen-deprived products of combustion and pyrolysis.
- Explosive growth and backdraft are similar, but differ in the rate of air introduction and the resulting force and speed of the ignition.
Reading Smoke
- Reading smoke is a skill set that combines the ability to identify smoke characteristics, analyze factors influencing the smoke, and make judgments regarding the location, phase, and spread potential of a fire in a building.
- Understanding smoke characteristics can help in making judgments regarding the location, phase, and spread potential of a fire, as well as the likelihood of a hostile fire event.
Smoke Movement
- Smoke movement can indicate the heat and location of a fire.
- Two forces cause smoke to pressurize in a building: convection heat or smoke volume.
- Types of smoke movement include heat-pushed smoke, volume-pushed smoke, turbulent smoke, and laminar smoke.
Importance of Smoke Density
- Thicker smoke can indicate a more severe fire event.
- Comparing smoke velocity at different openings can help determine the location of the fire.
Properties of Smoke
- Smoke can displace air and cause a fire to become ventilation-limited.
- Hydrocarbons in smoke can self-ignite as low as 450°F (232°C).
- Smoke from a typical house fire is amazingly explosive due to the presence of hydrocarbons.
- Pyrolysis often leads to combustion.
Importance of PPE
- Smoke is extraordinarily dangerous to health and can enter the human body through various methods.
- Toxic chemicals found in smoke can lead to short-term and chronic health issues, including an increased risk of cancer.
- The use of SCBA and PPE cannot be overstated—don't breathe smoke!### Fire Behavior and Smoke
- Black fire: a slang term for smoke that is high-volume, has turbulent velocity, is ultra-dense, and is deep black; a sign of impending autoignition and flashover.
- Explosive growth phase: a rapid fire growth phenomenon that occurs when combustion air is reintroduced into a ventilation-controlled fire, leading to smoke flame-over and room flashovers.
- Flame-over: a hostile fire event that includes the ignition and sustained burning of the overhead smoke layer within a room and/or hallway.
- Flashover: a sudden hostile fire event that occurs when all the surfaces and contents of a space reach their ignition temperature nearly simultaneously, resulting in full-room fire involvement.
- Flow path: an avenue that heat, smoke, flames, and combustion air follow.
- Ghosting: a hostile fire event warning sign that is characterized as turbulent smoke that has filled a room, moving faster than firefighters can crawl, and exterior vent-point ignition.
Hostile Fire Events
- Explosive growth phase
- Flashover
- Backdraft
- Smoke explosion
- Flame-over
- Hostile fire events can suddenly harm firefighters.
Smoke Behavior
- Smoke should sink and remain dense, but if it rises straight up and does not cool quickly, it indicates an exceptionally hot fire.
- Low-lying smoke can indicate a deep-seated fire or a fire not being controlled by a sprinkler system.
- Thermal balance is when heat of combustion collects at the ceiling and cool air flows to the fire below it.
Smoke Observations
- Container size: smoke observations must be analyzed in proportion to the building.
- Light, thin smoke showing from more than one opening of a very large building is a significant observation.
- All four attributes of smoke (volume, velocity, density, and color) should change in a positive, continuous manner if fire stream and ventilation efforts are appropriate.
Forced-Ventilation Tactics
- Forced-ventilation tactics should cause an increase in smoke velocity at the designated exhaust flow path exit.
- Positive-pressure attack (PPA) has gained popularity for fire attack.
- ISOs should monitor smoke conditions and firefighter actions and make an intervention to stop or alter PPA tactics in certain situations.
Warning Signs
- Warnings to shut down PPA tactics:
- Fire behavior and smoke flow do not increase at the exhaust opening after a full minute of air introduction.
- Smoke VVDC leaving other portions of the building (not the exhaust opening) intensify, getting darker, thicker, and/or turbulent.
- Fire is discovered behind advancing firefighters.
- Firefighters entering the building (after the fan is introduced) report zero visibility and high heat while advancing to the fire.
Reading Smoke
- The three-step process for reading smoke:
- View the smoke VVDC and compare the differences in the attributes from each opening from which smoke is emitting.
- Analyze the contributing factors to determine whether they are affecting VVDC.
- Determine the rate of change of each attribute.
- Importance of practicing the skill of reading smoke:
- Practice is necessary to develop the skill of reading smoke.
- Real-world experience is important, as opposed to simulated or theatrical smoke.
Smoke Attributes
- Volume: tells little about a fire but provides an impression regarding the potential size of an event.
- Velocity: very telling, turbulent velocity indicates serious heat or a flashover looms, laminar velocity means the box is absorbing heat.
- Density: indicative of the severity of hostile events.
- Color: rarely tells of the type of material burning, it tells the level of heating that is present:
- Black: hot
- White: cool
Health and Safety
- Thick, black smoke in a compartment reduces the chance of life sustainability due to smoke toxicology.
- A few breaths of thick, black smoke renders a victim unconscious and causes death in minutes.
- Smoke density is an indicator that gross decontamination processes must be implemented on-scene.
- Smoke can contain cancer-causing substances that must be removed from PPE surfaces to minimize spread and reduce the risk of skin/lung exposure once gear is doffed.
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Description
Test your knowledge on smoke breakdown and its components including particulates like soot and ash. Learn about how smoke is not always caused by burning materials but by pyrolysis, and how heat from burning materials can degrade the composition of materials to produce smoke.
