Chapter 6: Reading Smoke
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Questions and Answers

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?

  • Gases
  • Ash
  • Particulates (correct)
  • Aerosols

    • 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?

    <p>Ash</p> Signup and view all the answers

    Which chemical compound found in smoke can affect fire behavior and poses a danger to health?

    <p>Acrolein</p> Signup and view all the answers

    Why is the use of SCBA and PPE emphasized when dealing with smoke?

    <p>To prevent skin absorption of toxic chemicals in smoke</p> Signup and view all the answers

    What phase of fire growth model is characterized by a compartmentalized fire condition with open flaming decreasing due to limited available air?

    <p>Ventilation-limited phase</p> Signup and view all the answers

    Which of the following is NOT considered a hostile fire event?

    <p>Pyrolysis</p> Signup and view all the answers

    In which phase of fire growth does pyrolysis begin and smoke production becomes abundant?

    <p>Initial growth phase</p> Signup and view all the answers

    What are the warning signs of a backdraft event in a closed pressurized box?

    <p>Bowing, black-stained windows</p> Signup and view all the answers

    What is the rapid fire growth phenomenon that occurs when combustion air is reintroduced into a ventilation-controlled fire?

    <p>Explosive growth phase</p> Signup and view all the answers

    '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?

    <p>Initial growth phase</p> Signup and view all the answers

    'Dense smoke appears to have totally filled a building, floor to ceiling.' What hostile fire event does this scenario suggest?

    <p>Smoke explosion</p> Signup and view all the answers

    'Turbulent smoke flow that has filled a compartment' is characteristic of which hostile fire event?

    <p>Flame-over</p> Signup and view all the answers

    'Yellowish-gray smoke emitting from cracks and seams.' What hostile fire event does this statement point towards?

    <p>Backdraft</p> Signup and view all the answers

    'Smoke that rapidly speeds up when an exterior door is opened.' What stage of hostile fire events might this describe?

    <p>Backdraft</p> Signup and view all the answers

    What is the flammable range of smoke in air?

    <p>1% to 74%</p> Signup and view all the answers

    What triggers can cause accumulated smoke to ignite?

    <p>The right temperature and the right mixture</p> Signup and view all the answers

    How does the ignition of accumulated smoke change the fire spread dynamics?

    <p>The fire spreads with the smoke flow</p> Signup and view all the answers

    What is a key factor influencing compartmentalized fire growth?

    <p>The type, quantity, and continuity of the fire load</p> Signup and view all the answers

    Why is understanding smoke considered important in firefighting?

    <p>Smoke is the fire talking to you, predicting the future</p> Signup and view all the answers

    How did NIST and UL secure federal grant monies in the late 1990s?

    <p>To research modern fire behavior</p> Signup and view all the answers

    What was identified as inadequate for certain fires in relatively small buildings?

    <p>Interior hand lines</p> Signup and view all the answers

    When do smoke gases need only a proper air mix and a sudden spark or flame to ignite?

    <p>When they are below their ignition temperature</p> Signup and view all the answers

    What does brown smoke from structural spaces, such as OSB and LVL, indicate?

    <p>Impending collapse in engineered wood products</p> Signup and view all the answers

    What does white smoke that is fast-moving and dirty indicate in a fire incident?

    <p>Long distance traveled by the smoke</p> Signup and view all the answers

    What does the term 'black fire' refer to in relation to smoke?

    <p>Smoke ready for autoignition and flashover</p> Signup and view all the answers

    What is the indication of white smoke being all black eventually?

    <p>Heating of solid materials</p> Signup and view all the answers

    How does thermal balance influence the appearance of smoke in a fire incident?

    <p>Should be considered when interpreting smoke</p> Signup and view all the answers

    What does high-velocity, very thin black smoke indicate in a fire?

    <p>Flame-pushed smoke</p> Signup and view all the answers

    Why is it important to remove cancer-causing substances from Personal Protective Equipment (PPE) surfaces?

    <p>To reduce the risk of skin/lung exposure post-gear removal</p> Signup and view all the answers

    What does the thickness of black smoke in a compartment indicate about life sustainability?

    <p>Reduced chance of life sustainability due to smoke toxicology</p> Signup and view all the answers

    What is indicated by fast-moving, dirty white smoke in terms of fire intensity?

    <p>High intensity fire with some distance traveled by the smoke</p> Signup and view all the answers

    Why do most fire service curriculums consider teaching about smoke color misleading?

    <p>Smoke color cannot indicate the type of material burning</p> Signup and view all the answers

    What is the defining characteristic of 'black fire'?

    <p>High-volume and turbulent smoke</p> Signup and view all the answers

    During which fire growth phenomenon does combustion air reintroduction lead to smoke flame-over?

    <p>Explosive growth phase</p> Signup and view all the answers

    What defines a 'hostile fire event' that includes flame-over?

    <p>Ignition of the overhead smoke layer</p> Signup and view all the answers

    What characterizes 'intermittent ignition' in fire behavior terms?

    <p>Fingers of flame dancing through upper smoke layer</p> Signup and view all the answers

    Which fire behavior phenomenon involves a spark or flame igniting a pocket of smoke rapidly?

    <p>Smoke explosion</p> Signup and view all the answers

    What is the primary function of a flow path in fire behavior?

    <p>Avenue for heat, smoke, and combustion air movement</p> Signup and view all the answers

    What are the four distinctive characteristics of smoke mentioned in the text?

    <p>Volume, velocity, density, color</p> Signup and view all the answers

    Which characteristic of smoke can indicate the amount of fuels off-gassing in a space?

    <p>Smoke volume</p> Signup and view all the answers

    What does backdraft refer to in relation to a fire event?

    <p>Sudden reintroduction of air causing explosive event</p> Signup and view all the answers

    What warning sign for hostile fire events is considered dangerously late according to the text?

    <p>Sensation of heat</p> Signup and view all the answers

    Which type of smoke movement warrants more attention due to being caused by convection heat?

    <p>Heat-pushed smoke</p> Signup and view all the answers

    What does laminar smoke flow indicate about a fire?

    <p>Presence of life-sustaining conditions</p> Signup and view all the answers

    Which characteristic of smoke can help determine the location of a fire by comparing its velocity at different openings?

    <p>Volume</p> Signup and view all the answers

    What does low-lying smoke typically indicate in a building fire?

    <p>A deep-seated fire</p> Signup and view all the answers

    What can light, thin smoke showing from more than one opening of a very large building indicate?

    <p>A significant observation</p> Signup and view all the answers

    What does it indicate if smoke becomes darker and thicker when ventilation fans are being used?

    <p>Fans are making conditions worse</p> Signup and view all the answers

    Why did Positive-Pressure Attack (PPA) gain popularity for fire attack?

    <p>To improve firefighter safety</p> Signup and view all the answers

    What are some warnings to shut down Positive-Pressure Attack (PPA) tactics?

    <p>Smoke getting darker and thicker after fan introduction</p> Signup and view all the answers

    What do turbulent smoke that fills a box and thick, black, fast smoke typically indicate, respectively?

    <p>Impending flashover, close to the seat of the fire</p> Signup and view all the answers

    What is the importance of practicing the skill of reading smoke?

    <p>To prevent firefighter injury or death</p> Signup and view all the answers

    What does thin, black, fast smoke typically indicate in a fire scenario?

    <p>Fire nearby that is well ventilated</p> Signup and view all the answers

    Why should ISOs be well-versed in Positive-Pressure Attack (PPA) tactics?

    <p>To achieve controlled air and exhaust flow path for firefighting</p> Signup and view all the answers

    What warning sign does brown smoke typically indicate during a firefighting operation?

    <p>Unfinished wood reaching late heating</p> Signup and view all the answers

    What is the primary importance of open flaming in a building fire according to the text?

    <p>It helps minimize the products of combustion and provides heat, light, carbon dioxide, and water vapor</p> Signup and view all the answers

    What triggers can cause accumulated smoke to ignite according to the text?

    <p>The correct air mix and a sudden spark or flame</p> Signup and view all the answers

    What happens when smoke gases reach their ignition temperature in a ventilation-limited fire?

    <p>They need only the right mixture in the air for ignition</p> Signup and view all the answers

    What change in fire spread dynamics occurs when accumulated smoke ignites?

    <p>Fire spreads with the smoke flow instead of across surfaces of contents</p> Signup and view all the answers

    What was identified as inadequate for certain fires in relatively small buildings according to the text?

    <p>Interior hand lines</p> Signup and view all the answers

    What is the collective flammable range of smoke in air according to the text?

    <p>1% to 74%</p> Signup and view all the answers

    What ultimately dictates fire behavior according to the text?

    <p>'Fire talking' phenomenon</p> Signup and view all the answers

    "Traditional teaching has described a four-phase growth model for a building fire." How many phases does the text suggest for interior building fires?

    <p>'A six-phase' growth model</p> Signup and view all the answers

    "The size, type, quantity, and continuity of the fire load" are factors influencing which of the following aspects according to the text?

    <p>'Compartmentalized Fire Growth'</p> Signup and view all the answers

    "Watching smoke flow can help understand what is about to happen." According to the text, what does smoke represent as a form of communication?

    <p>'Future telling'</p> Signup and view all the answers

    What is the main difference between soot and ash in smoke?

    <p>Soot is carbon-based while ash consists of trace metals and minerals</p> Signup and view all the answers

    What is the primary reason why hydrocarbons in smoke are considered dangerous?

    <p>They can enter the human body and pose health risks</p> Signup and view all the answers

    Why is pyrolysis important in understanding smoke's behavior?

    <p>It chemically breaks down compounds into other substances without combustion</p> Signup and view all the answers

    Which of the following statements about fire gases in smoke is true?

    <p>Fire gases can displace air and make a fire ventilation-limited</p> Signup and view all the answers

    How do aerosols contribute to the composition of smoke at a structure fire?

    <p>By suspending or propelling liquids like moisture, hydrocarbons, and acids</p> Signup and view all the answers

    What characteristic of smoke contributes to causing a fire to become ventilation-limited?

    <p>The capability of smoke to displace air</p> Signup and view all the answers

    What phase of fire growth is characterized by a compartmentalized fire condition where open flaming decreases due to limited available air?

    <p>Ventilation-limited phase</p> Signup and view all the answers

    Which hostile fire event involves a sudden and rapid increase in pressure due to the ignition of smoke?

    <p>Smoke explosion</p> Signup and view all the answers

    What signifies the beginning of pyrolysis and abundant smoke production in a fire incident?

    <p>Initial growth phase</p> Signup and view all the answers

    What is a common warning sign for hostile fire events that can be considered dangerously late according to the text?

    <p>Rollover</p> Signup and view all the answers

    '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?

    <p>Initial growth phase</p> Signup and view all the answers

    'Dense smoke appears to have totally filled a building, floor to ceiling.' What hostile fire event does this scenario suggest?

    <p>Flashover</p> Signup and view all the answers

    'Yellowish-gray smoke emitting from cracks and seams.' What hostile fire event does this statement point towards?

    <p>Backdraft</p> Signup and view all the answers

    'Smoke that is being trapped in a separate space above the fire.' What hostile fire event does this scenario suggest?

    <p>Smoke explosion</p> Signup and view all the answers

    'Increase in smoke speed. Ghosting. Laminar flow of smoke that becomes turbulent.' These signs are most likely indicative of:

    <p>'Flashover'</p> Signup and view all the answers

    What characterizes 'intermittent ignition' in fire behavior terms?

    <p>Fingers of flame dancing through the upper smoke layer</p> Signup and view all the answers

    What can a high volume of smoke indicate in a ventilation-limited environment?

    <p>A tremendous amount of fuels off-gassing</p> Signup and view all the answers

    In the context of smoke, what does a laminar flow typically indicate?

    <p>A stable fire condition</p> Signup and view all the answers

    What is the primary characteristic of heat-pushed smoke movements?

    <p>Caused by convection heat</p> Signup and view all the answers

    What does turbulent smoke velocity that fills a compartment typically indicate?

    <p>Imminent flashover</p> Signup and view all the answers

    What is the significance of comparing the velocity of smoke at different openings?

    <p>Determining the location of the fire</p> Signup and view all the answers

    Why should firefighters avoid crawling into a box filled with turbulent smoke?

    <p>To reduce risk of flashover occurrence</p> Signup and view all the answers

    What is indicated by thick, black smoke in a compartment?

    <p>Reduced chance of life sustainability due to toxicology</p> Signup and view all the answers

    What is the primary characteristic of black fire in a fire scenario?

    <p>It signifies imminent autoignition and flashover</p> Signup and view all the answers

    Which fire behavior term describes the overhead smoke layer igniting and burning within a room or hallway?

    <p>Flame-over</p> Signup and view all the answers

    What is the consequence of reintroducing combustion air into a ventilation-controlled fire?

    <p>Room flashover</p> Signup and view all the answers

    Which fire behavior phenomenon involves a spark or flame igniting a pocket of smoke rapidly?

    <p>Smoke explosion</p> Signup and view all the answers

    What defines an avenue that heat, smoke, flames, and combustion air follow in a fire scenario?

    <p>Flow path</p> Signup and view all the answers

    What is pyrolysis primarily associated with in the context of fire behavior?

    <p>Chemical breakdown by heat alone</p> Signup and view all the answers

    What is the significance of smoke rising straight up without quickly cooling?

    <p>A deep-seated fire is indicated</p> Signup and view all the answers

    When smoke becomes thicker and darker while ventilation fans are used, what does it suggest about the fan action?

    <p>It is causing worse conditions</p> Signup and view all the answers

    In fire behavior terms, what does turbulent velocity of smoke indicate?

    <p>A flashover is imminent</p> Signup and view all the answers

    What does dirty white smoke with velocity indicate in terms of fire intensity?

    <p>Heat-pushed smoke traveling a distance</p> Signup and view all the answers

    What does thick, black, fast smoke typically indicate in a fire incident?

    <p>'Black fire' transitioning into structure fire</p> Signup and view all the answers

    If light, thin smoke is observed from more than one opening of a large building, what does it suggest?

    <p>A deep-seated fire or combustible voids</p> Signup and view all the answers

    What does low-volume white smoke from multiple locations of a large building indicate?

    <p>'Brown fire' from unfinished wood heating up</p> Signup and view all the answers

    When analyzing smoke observations in proportion to the building, why must the observer consider container size?

    <p>'Brown fire' transition into structure fires</p> Signup and view all the answers

    What does white smoke indicate in terms of fire location?

    <p>Low heat and early stages of heating</p> Signup and view all the answers

    What does the presence of fast-moving, dirty white smoke suggest?

    <p>Smoke has traveled a significant distance</p> Signup and view all the answers

    What can brown smoke from structural spaces indicate?

    <p>Impending structural collapse</p> Signup and view all the answers

    How does smoke color change as materials are further heated?

    <p>White to brown to black</p> Signup and view all the answers

    What is the relation between smoke density and gross decontamination processes?

    <p>High smoke density indicates the need for decontamination processes</p> Signup and view all the answers

    What is the primary danger associated with smoke from a typical house fire?

    <p>Presence of hydrocarbons making the smoke highly explosive</p> Signup and view all the answers

    What is the main reason why SCBA and PPE are crucial when dealing with smoke in fire suppression activities?

    <p>To avoid inhaling toxic chemicals present in smoke</p> Signup and view all the answers

    Which statement best describes the process of pyrolysis in the context of fire behavior?

    <p>Pyrolysis is the chemical breakdown of compounds into other substances by heat alone</p> Signup and view all the answers

    What makes smoke displacement a critical factor that can affect fire behavior?

    <p>Displacement reduces oxygen levels, slowing down combustion</p> Signup and view all the answers

    Why are hydrocarbons in smoke specifically highlighted as self-igniting at low temperatures?

    <p>Hydrocarbons can self-ignite as low as 450°F, contributing to explosive smoke</p> Signup and view all the answers

    What role do suspended or propelled liquids play in the composition of smoke at a structure fire?

    <p>Liquids form aerosols in smoke, including moisture, hydrocarbons, and acids</p> Signup and view all the answers

    What can initiate the ignition of smoke gases that are below their ignition temperature?

    <p>A proper air mix and a sudden spark or flame</p> Signup and view all the answers

    Why is open flaming considered beneficial according to the text?

    <p>To render heat, light, and water vapor</p> Signup and view all the answers

    What leads to an off-gassed smoke causing an underventilated condition in a ventilation-limited fire?

    <p>Displacement of air by smoke gases</p> Signup and view all the answers

    What is the primary implication for fire behavior when accumulated smoke is pressurized within a room?

    <p>Expansive surge upon ignition</p> Signup and view all the answers

    Which factor influences compartmentalized fire growth according to the text?

    <p>Size and status of exterior openings</p> Signup and view all the answers

    Why was research into modern fire behavior initiated by NIST and UL, according to the text?

    <p>Due to ineffective classic tactical ventilation methods</p> Signup and view all the answers

    What is the significance of smoke according to the text?

    <p>It can predict future fire behavior</p> Signup and view all the answers

    When does smoke from low-mass materials reach ignition temperature without needing a spark or flame?

    <p>&quot;Once it has the right mixture in air&quot;</p> Signup and view all the answers

    What does white smoke emitted by solid materials when first heated mainly consist of?

    <p>Ammonia and phenols</p> Signup and view all the answers

    What does brown smoke from structural spaces, like those containing OSB and LVL, warn of according to the text?

    <p>Impending collapse</p> Signup and view all the answers

    What is the significance of black fire in a fire scenario?

    <p>Warns of autoignition and flashover</p> Signup and view all the answers

    What does fast-moving, dirty white smoke indicate about a fire's characteristics?

    <p>Smoke traveled some distance</p> Signup and view all the answers

    How does smoke velocity assist in determining the distance to a fire?

    <p>It deposits content along surfaces</p> Signup and view all the answers

    What can be inferred when smoke is brown in color within a structure?

    <p>Critical strength may have been lost</p> Signup and view all the answers

    How does smoke color change as materials are further heated according to the text?

    <p>From white to black</p> Signup and view all the answers

    What does high-velocity, very thin black smoke in a fire scenario indicate?

    <p>Flame-pushed smoke</p> Signup and view all the answers

    What warning sign does thick, black, fast smoke typically provide in a fire incident?

    <p>Impending danger due to toxicology</p> Signup and view all the answers

    What is the primary composition of white smoke emitted when solid materials are first heated according to the text?

    <p>Ammonia and phenols</p> Signup and view all the answers

    What does laminar smoke flow typically indicate?

    <p>The interior of the space is still absorbing heat</p> Signup and view all the answers

    What does heat-pushed smoke indicate?

    <p>Serious heat bouncing around</p> Signup and view all the answers

    What can a high volume of smoke indicate in a ventilation-limited environment?

    <p>The amount of fuels off-gassing in the space</p> Signup and view all the answers

    What warning sign does black smoke in a compartment suggest?

    <p>Presence of more heat</p> Signup and view all the answers

    In fire behavior terms, what is 'turbulent smoke velocity that fills a compartment' indicative of?

    <p>A flashover is imminent</p> Signup and view all the answers

    What does the thickness of smoke typically indicate?

    <p>The amount of fuel in the smoke</p> Signup and view all the answers

    '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?

    <p>'Laminar flow that becomes turbulent'</p> Signup and view all the answers

    '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?

    <p>'Stable fire'</p> Signup and view all the answers

    What is the primary characteristic of a flame-over event in a fire scenario?

    <p>Ignition of surfaces and contents simultaneously</p> Signup and view all the answers

    During which fire growth phenomenon does smoke flame-over occur?

    <p>Explosive growth phase</p> Signup and view all the answers

    What is pyrolysis primarily associated with in the context of fire behavior?

    <p>Chemical breakdown of compounds by heat alone</p> Signup and view all the answers

    Which component of smoke is characterized by high surface-to-mass and easy ignition properties?

    <p><strong>Fire gases</strong></p> Signup and view all the answers

    What defines an avenue that heat, smoke, flames, and combustion air follow in a fire scenario?

    <p><strong>Flow path</strong></p> Signup and view all the answers

    What is the flammable range of smoke in air according to the text?

    <p>$6-15%$</p> Signup and view all the answers

    What phase is characterized by a compartmentalized fire condition with open flaming decreasing due to smoke production?

    <p>Ventilation-limited phase</p> Signup and view all the answers

    What event is described as a sudden and rapid increase in pressure caused by the ignition of smoke?

    <p>Smoke explosion</p> Signup and view all the answers

    Which fire behavior term refers to smoke that is rapidly heated, leading to a more sudden and violent event?

    <p>Smoke explosion</p> Signup and view all the answers

    What does the text suggest is the primary characteristic of 'black fire' in a fire scenario?

    <p>High-velocity flames</p> Signup and view all the answers

    What is indicated by laminar smoke flow transitioning into turbulent flow in a fire incident?

    <p>Growing fire behavior</p> Signup and view all the answers

    'Yellowish-gray smoke emitting from cracks and seams.' What hostile fire event does this statement point towards?

    <p>Backdraft</p> Signup and view all the answers

    'Dense smoke appears to have totally filled a building, floor to ceiling.' What hostile fire event does this scenario suggest?

    <p>Flame-over</p> Signup and view all the answers

    What warning sign does 'laminar flow of smoke that is becoming turbulent' indicate during a firefighting scenario?

    <p>Growing fire behavior intensity</p> Signup and view all the answers

    What can be inferred from the presence of 'laminar flow of smoke that is becoming turbulent' in a building fire?

    <p>Growing fire behavior in the space</p> Signup and view all the answers

    What is characterized by an increase in smoke speed from tightened openings upon external entry during a hostile fire situation?

    <p>Backdraft</p> Signup and view all the answers

    What is a warning sign of an exceptionally hot fire, according to the text?

    <p>Smoke that rises straight up and does not cool quickly</p> Signup and view all the answers

    What does light, thin smoke showing from multiple openings of a very large building indicate, as per the text?

    <p>A deep-seated fire</p> Signup and view all the answers

    What does thick, black, fast smoke typically suggest in a fire incident?

    <p>Super-hot smoke capable of instant ignition</p> Signup and view all the answers

    What is a key factor for firefighters to consider when forced-ventilation tactics are being used, based on the text?

    <p>Smoke becoming darker and thicker with fan usage</p> Signup and view all the answers

    What is the primary purpose of Positive-Pressure Attack (PPA) in firefighting, according to the text?

    <p>To achieve controlled conditions and improve firefighter safety</p> Signup and view all the answers

    What should firefighters look for as firefighting efforts progress during an incident, according to the text?

    <p>Darker smoke when ventilation is effective</p> Signup and view all the answers

    What does turbulent smoke velocity filling a compartment typically indicate?

    <p>'Turbulent velocity' meaning serious heat or impending flashover</p> Signup and view all the answers

    What does the volume of smoke primarily indicate in terms of fire size?

    <p>'Volume tells little about a fire's size but gives an idea of event potential'</p> Signup and view all the answers

    What does light, thin smoke showing from more than one opening of a very large building typically suggest?

    <p>A deep-seated fire</p> Signup and view all the answers

    What should ISOs look for when practicing reading smoke?

    <p>Positive changes in smoke conditions as firefighting efforts progress</p> Signup and view all the answers

    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

    • Real-world experience is important for developing the skill of reading smoke

    • Practice is necessary to improve the skill of reading smoke

    • Use raw, fire-ground video footage for practice### Black Fire and Hostile Fire Events

    • Black fire refers to high-volume, turbulent, and ultra-dense smoke that is a sign of impending autoignition and flashover.

    • 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:
      1. View the smoke VVDC and compare the differences in the attributes from each opening from which smoke is emitting.
      2. Analyze the contributing factors to determine whether they are affecting VVDC.
      3. 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.

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