Ch. 7: Reading Smoke Flashcards
Smoke leaving a structure has four key attributes:
volume, velocity (pressure), density, and color
The product of incomplete combustion that includes an aggregate of solids, aerosols, and fire gases that are toxic, flammable, and volatile.
smoke
What can help the ISO determine the size and location of the fire, the effectiveness of fire streams, as well as the potential for a hostile fire event like a flashover?
A comparative analysis of the attributes of smoke.
What is a by-product of incomplete combustion, specifically particulates (solids) that were suspended in a thermal column?
Smoke
What is an explosive aggregate of solids, aerosols, and gases?
smoke
Good thing: The products of combustion are minimized because the burning process is more complete.
“Open flaming”
What happens when materials can only absorb so much heat before it starts to break down and “off-gas” without flaming?
Smoke becomes flammable.
_________ is extremely flammable and ultimately dictates fire behavior in a building.
Smoke
What are the two triggers that may cause accumulated smoke to ignite?
The right temperature and the right mixture.
What will the ignition of flame spread across surfaces of contents do to fire?
The fire spreads with the smoke flow.
What tells you how intense the fire is about to become as opposed to how bad it currently is?
Watching the smoke.
An event that can catch firefighters off guard and endanger them: flashover, backdraft, smoke explosions, and rapid fire spread.
Hostile fire event
All gases reach their ignition temperature at virtually the same time due to rapid heat buildup in the box.
Flashover
What event will show warning signs of turbulent smoke flow, rollover, and autoignition outside?
Flashover
What is suspected when there is sucking or puffing witnessed near a box?
Backdraft
What event happens when a spark or flame is introduced into trapped smoke that is below its ignition temperature but above its flashpoint?
Smoke explosion
What event happens when smoke reaches sustaining temperatures that are above the fire point of prevalent gases?
Rapid fire spread
The ISO must study the warning signs of hostile fire events and watch for the signs as part of the reading smoke process.
The ISO must study the warning signs of hostile fire events and watch for the signs as part of the reading smoke process.
Warning signs -
- Turbulent smoke flow
- Rollover
- Autoignition outside
Flashover
Warning signs -
- Yellowish-gray smoke
- Bowing, black stained windows
- Signs of extreme heat on outside of box/compartment
Backdraft
Warning signs -
- Smoke that is being trapped above the fire
- Signs of a growing fire
- Signs of smoke starting to pressurize
Smoke explosion
Warning signs -
- Increase in smoke speed
- Smoke flowing from hallways and stairways faster than a firefighter can move
Rapid fire spread
What type of approach must an ISO take by watching the four smoke attributes?
A proactive approach
What can help the ISO understand fire behavior?
By comparing the smoke volume, velocity, density, and color.
What by itself tells very little about a fire, but it sets the stage for understanding the amount of fuel that are off-gassing in a given space?
smoke volume
A hot clean-burning fire.
Emits very little visible smoke
A hot, fast moving fire in an underventilated building.
Shows a tremendous volume of smoke.
What burns slowly and emits lots of smoke (typically of a lighter color)?
Dampened materials
The movement of smoke through a building that is rapid and violent and that has expansive velocity (sometimes referred to as “agitated,” “boiling,” or “angry” smoke); indicates that the building (or compartment) cannot absorb more heat and is precursor warning sign of a flashover.
Turbulent smoke flow
What characteristic means a flashover is likely to occur?
turbulent smoke flow
What is a precursor to flashover?
turbulent smoke flow
The “speed” at which smoke leaves a building is reffered to as ___________.
velocity
What is an indicator of pressure that has built up in the building?
smoke velocity
What are the two things from a practical fire behavior point of view that can cause smoke to pressurize in a building?
Heat or smoke volume
What is caused by the rapid molecular expansion of the gases in the smoke and the restriction of this expansion by the box (compartment)?
turbulent smoke flow
When smoke is leaving the building, its velocity is caused by?
Heat if it rises and then slows gradually.
What does smoke caused by restricted volume do?
Immediately slows down and becomes balanced with outside airflow.
What does the smooth and stable flow of smoke through a building indicate?
The building (or compartment) is still absorbing heat.
If the box is still absorbing heat, the heat of the smoke is subsequently absorbed, leaving a more stable and smooth flow characteristic that is referred to as ________ _________ _________.
laminar smoke flow
What word is used to describe the smooth movement of a fluid, and smoke is basically fluid when moving through a building?
“laminar”
What is the most important smoke observation?
Whether the smoke’s flow is turbulent or laminar.
What is ready to ignite and indicates a flashover environment that may be delayed by improper air mix?
Turbulent smoke
What can help the fire officer determine the location of the fire?
Comparing the velocity of smoke at different openings of the building.
What visual of smoke tells you its closer to the fire?
Faster smoke
What tells you how hot it is and where the fire is?
Velocity
What smoke attribute tells you how bad things are going to be?
Density
What refers to the thickness of the smoke?
density
What attribute of smoke tells you how much fuel is laden in the smoke?
density (thickness)
The thicker the smoke, the more spectacular the flashover or fire spread will be.
The thicker the smoke, the more spectacular the flashover or fire spread will be.
What attribute also sets up fuel continuity?
smoke thickness
What spreads a fire event (like flashover) farther than less dense smoke?
Thick smoke
What can ignite because of the continuity of the fuel to the source?
thick, laminar-flowing smoke
What reduces the chance life sustainability due to smoke toxicology?
Thick, black smoke in a compartment
What is the firefighter crawling through zero-visibility smoke actually crawling through?
Ignitable fuel
What indicates the “type” of material that is burning?
Smoke color
What does smoke color tell the ISO?
The stage of heating and points to the location of the fire in a building.
When smoke emits white, what is this mostly?
Moisture
Virtually all solid materials emit a ________ “smoke” when first heated.
white
What happens to the smoke color as a material dries out and breaks down?
The color of the smoke darkens.
The more black the smoke you see, the hotter the smoke is.
The more black the smoke you see, the hotter the smoke is.
What does it mean when black smoke that is high velocity and very thin (low density) mean?
It is flame pushed (open (and ventilated) flaming is nearby).
What does brown smoke from structural spaces indicate?
The fire is transitioning from a contents fire to a structural fire.
What does brown smoke from structural spaces containing glued trusses, OSB, or LVL can indicate?
That critical strength has been already lost.
What does fast moving white smoke indicate?
That the smoke has traveled some distance.
What is it most likely indicative of when white smoke is slow or lazy?
Early-stage heating
What does the issuance of brown smoke from gabled-end vents, eaves, and floor seams a warning sign of?
Impending collapse
What can help locate a fire?
Compare smoke velocity and color from various openings.
Faster and/or darker smoke is closer to the fire seat, whereas slower and/or lighter smoke is…
farther away
What indicates that unfinished wood is being heated?
Brown smoke from structural spaces.
What should you start thinking when the smoke appears uniform - that is, it is the same color and velocity from multiple openings?
That the fire is in a concealed space (or deep-seated)
What should the ISO inform the IC upon seeing smoke that is the same color and velocity being pushed from multiple building seams?
That the fire may have extended to concealed spaces.
A slang term used to describe high-volume, turbulent, ultradense, and deep-black smoke; a sure sign of impending flashover.
Black fire
What can reach temperatures of over 1,000 degrees Fahrenheit?
Black fire
What is a sure sign of impending autoignition and flashover?
Black fire
What can change the appearance of smoke?
Weather, thermal balance, container size, and firefighting efforts.
What can influence the smoke’s appearance once it leaves a building?
The outside weather
When outside air temperatures are below freezing, hot smoke leaving the building will?
Turn white almost instantly.
What can happen to firefighters engaged in an interior fire attack downwind of a wind-fed fire?
In danger of being overrun by the fire.
What in the air increases resistance to smoke movement by raising air density?
Humidity
A hot day finds the smoke rising much farther because cooling is more difficult.
A hot day finds the smoke rising much farther because cooling is more difficult.
If the outside air is cooler than the smoke, the smoke should rise until the outside air _______ ______.
cools it
What happens when hot, dry smoke contacts cold, humid air?
It changes white.
What happens when hot, moist smoke contacts cold, dry air?
It turns white.
What does the presence of low-lying smoke indicate in a sprinkled building?
That the fire is not being controlled by sprinklers.
What is the notion that heated smoke rises and in doing so creates a draft of cool air into the flame (heat) source?
thermal balance
What does sucking, puffing, and “breathing” signs indicate?
That a fire is out of thermal balance.
From the ISO’s perspective, signs of air being sucked into a building indicate that the fire is intense, yet struggling for proper airflow.
A sudden inflow of air can cause the fire to take off - trapping firefighters.
What concern does light, thin smoke from more than one opening of a very large building?
It is a significant observation.
When a fire stream and ventilation efforts are appropriate, what should happen?
All four attributes of smoke should change in a positive, continuous manner.
Who is usually in the best position to tell whether firefighting efforts are being successful?
The ISO
What is contraindicated if smoke is turbulent (a flashover warning sign)?
PPV
How can the ISO refine and rapidly apply principle to be incorporated into a process for rapid application?
Following three simple steps:
1) View VVDC of smoke.
2) Analyze the contributing factors to determine if affecting VVDC.
3) Determine the rate of change of each attribute.
What should give ISOs a good understanding of the fire and help them predict what the fire will do next?
The three-step process
What is founded on an understanding of the physical and chemical properties of smoke as well as the specific warning signs of impending hostile events?
Predicting fire behavior
What can be compared to paint a picture of the fire in a building?
Smoke volume, velocity, density, and color.
What is the smooth and stable flow of smoke through a
building called?
Laminar smoke flow
Which is NOT considered a positive change in smoke
conditions once firefighting efforts are underway?
Contents that were flaming should start “smoking black”
Which hostile fire event is preceded by an increase in
smoke speed and smoke flowing from hallways faster than a
firefighter can move?
Rapid fire spread
What gas is produced when high temperatures break down nitrogen-containing products?
Hydrogen cyanide
With black fire what is doing the damage?
Smoke
What shortcut has been shared as the fastest way to find a fire in the building?
Look for the fastest smoke from the most resistive opening
What should the smoke be doing on a hot, humid day?
Climbing straight up into the atmosphere
Which is a trigger that may cause accumulated smoke to
ignite?
Right temperature
Which is NOT a key attribute of smoke leaving a structure?
Odor
What does smoke volume by itself set the stage for
understanding?
Amount of fuel that are off-gassing in a given space
What color smoke from structural spaces can indicate the
fire is moving from a contents fire to a structural fire?
Brown
Which is NOT a sign that the fire inside is out of thermal
balance?
Jetting
What is moving smoke that is black, high velocity and very thin?
Flame
What will most likely be seen when there is a deep-seated fire?
Same color and same velocity smoke from multiple openings
Where is faster smoke seen in relation to the fire?
Closer to
In which type of building would light, thin smoke showing
from more than one opening be a sign of significant fire
inside?
Large warehouse
Which smoke is usually indicative of early-stage heating?
Slow moving white smoke
At what temperature (degrees Fahrenheit) does the
flammable range of CO become a factor?
300
What is the main content of white smoke?
Moisture
What is smoke velocity an indicator of?
Pressure
What ultimately dictates fire behavior in a building?
Smoke
What gas do most plastics release when burning?
Benzene
Which is a solid suspended in smoke?
Carbon
What color smoke do virtually all solid materials emit
when first heated?
White
Which hostile fire event is preceded by signs of a
growing fire and signs of smoke starting to pressurize?
Smoke explosion
What does thick black smoke say about the survivability
within a compartment?
It is very low
What smoke will most likely be seen when there is either a nearby fire that is well vented or flame-pushed smoke?
Thin, black smoke moving fast
What is the byproduct of incomplete combustion?
Smoke
Which hostile fire event is preceded by yellowish-gray
smoke and bowing, black stained windows?
Backdraft
Which gas commonly found in smoke has a flashpoint of -15 degrees Fahrenheit?
Acrolein
Which event is evidenced by turbulent smoke flow and
auto ignition outside?
Flashover
Name 4 Hostile fire events
Flashover
Backdraft
Smoke Explosion
Rapid Fire Spread
