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Reading Smoke
What are 4 key attributes of smoke leaving a structure?
- volume
- velocity (pressure)
- density
- color
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Reading Smoke
What is the definition of smoke?
The product of incomplete combustion (including an aggregate of solids, aerosols, and fire gases that are toxic, flammable, and volatile)
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Reading Smoke
What do solids suspended in a thermal plume include?
- carbon (soot and ash)
- dust
- airborne fibers
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Reading Smoke
What do smoke aerosols include?
- hydrocarbons (oils and tar)
- moisture
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Reading Smoke
What are 5 leading fire gases?
- carbon monoxide (CO)
- hydrogen cyanide (HCN)
- acrolein
- hydrogen sulfide
- benzene
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Reading Smoke
What is extremely flammable and ultimately dictates fire behavior in a building?
smoke
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Reading Smoke
What are 2 triggers that cause accumulated smoke to ignite?
- right temperature
- right mixture
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Reading Smoke
Smoke tells you how intense the fire is about to become as opposed to what?
as opposed to how bad it currently is
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Hostile Fire Events
What are 4 common hostile fire events?
- flashover
- backdraft
- smoke explosion
- rapid fire spread
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Hostile Fire Events
When does backdraft occur?
When oxygen is introduced into an environment where fire gases are above their ignition temperature and have been trapped in a box
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Hostile Fire Events
What hostile fire event occurs when a spark or flame is introduced into trapped smoke that is below its ignition temperature but above its flashpoint?
a smoke explosion
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Hostile Fire Events
What is a late sign of impending backdraft?
sucking of air
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Hostile Fire Events
What is a dangerously late warning sign?
sensation of heat
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Hostile Fire Events
The ISO must take a proactive approach by watching the 4 smoke attributes and determining what 3 things about a fire in a building?
- location
- stage
- spread potential
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Hostile Fire Events
What kind of fire shows a tremendous volume of smoke?
hot, fast moving fire in an underventilated building
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Hostile Fire Events
What can create an impression of the fire?
the volume of smoke
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Hostile Fire Events
What are 2 things that can cause smoke to pressurize in a building?
heat or smoke volume
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Hostile Fire Events
What causes the velocity of smoke leaving a building to rise and then slow gradually?
heat
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Hostile Fire Events
What causes smoke to immediately slow down and become balanced with outside airflow?
restricted volume
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Hostile Fire Events
What is turbulent smoke flow a precursor to?
flashover
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Hostile Fire Events
What is the movement of smoke through a building that is rapid and violent and has expansive velocity known as?
turbulent smoke flow
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Hostile Fire Events
Agitated, boiling, or angry smoke is also referred to as what?
turbulent smoke flow
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Hostile Fire Events
What is the expansion of the gases in the smoke caused by?
radiant heat feedback from the box itself
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Hostile Fire Events
What is the smooth and stable flow of smoke through a building called?
laminar smoke flow
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Hostile Fire Events
What is the most important smoke observation?
whether the flow is turbulent or laminar
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Hostile Fire Events
How can a fire officer determine the location of a fire?
By comparing the velocity of smoke at different openings of the building
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Hostile Fire Events
When comparing velocities to find the location of a fire, what type of openings do you compare?
only like-resistive openings
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Hostile Fire Events
What does the thickness of the smoke tell you?
how much fuel is laden in the smoke
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Hostile Fire Events
What does thick, black smoke in a compartment reduce the chance of?
life sustainability
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Hostile Fire Events
What does smoke color tell an ISO?
- stage of heating
- location of fire in a building
- distance to a fire
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Hostile Fire Events
When does virtually all solid materials emit a white smoke?
when first heated
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Hostile Fire Events
When do flames almost immediately off-gas black smoke?
When they touch surfaces that are not burning
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Hostile Fire Events
What does fast moving white smoke indicate?
that the smoke has traveled some distance
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Hostile Fire Events
The hotter the smoke is, what color does it become?
more black
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Hostile Fire Events
At what velocity and what density is black smoke?
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Hostile Fire Events
White smoke that is slow and lazy is indicative of what stage of heating?
early-stage heating
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Hostile Fire Events
What color does unfinished wood give off when it approaches late-stage heating (just prior to flaming)?
brown smoke
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Hostile Fire Events
What does brown smoke from structural spaces indicate?
fire is transitioning from a contents fire to a structural fire
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Hostile Fire Events
Brown smoke that comes from gable-end vents, eaves, and floor seams is a warning sign of what?
impending collapse
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Hostile Fire Events
When smoke appears with the same color and velocity from multiple openings, what kind of fire does that indicate?
a deep seated fire
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Hostile Fire Events
What is the slang term used to describe high-volume, turbulent, ultra-dense and deep black smoke?
black fire
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Hostile Fire Events
What is a sure sign of impending autoignition and flashover?
black fire
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Hostile Fire Events
What temperatures can black fire reach?
over 1000 degrees F
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Hostile Fire Events
In a black fire, what causes all the destruction that flames would cause?
the smoke itself
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Hostile Fire Events
True/False?
No firefighter should be in or near compartments emitting black fire.
true
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Other Factors that Influence Smoke
What 4 factors can change the appearance of smoke?
- weather
- thermal balance
- container size
- firefighting efforts
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Other Factors that Influence Smoke
What is virtually every element of smoke heavier than?
air
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Other Factors that Influence Smoke
In what kind of manner should all 4 attributes of smoke change if fire stream and ventilation efforts are appropriate?
in a positive, continuous manner
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