60 Questions
What are the two forces that cause smoke to pressurize in a building?
Convection heat or smoke volume
What is the characteristic of smoke caused by restricted volume?
It immediately slows down and balances with outside airflow
What is the significance of the speed of smoke in relation to heat?
The faster smoke moves, the more heat it has
How can the ISO make judgments regarding the location, phase, and spread potential of a fire in a building?
By analyzing the flow characteristic of smoke
What causes turbulent smoke?
Serious heat
What are the characteristics of laminar smoke flow?
Smooth, calm, or following a straight line
What does fast-moving, dirty white smoke indicate?
The smoke has traveled some distance, but a hot fire exists
What does brown smoke from structural spaces indicate?
Unfinished wood is being heated and is decomposing
What does black fire indicate?
Impending autoignition and flashover
How does weather affect smoke movement?
All of the above
What does low humidity in the air allow smoke to do?
Dissipate more easily
How does wind influence smoke leaving a building?
It can thin and dissipate smoke rapidly
What should be expected if the outside air temperature is well below freezing?
Hot, dark smoke leaving the building turns white almost instantly
What does black fire reaching temperatures of over 1,000°F (538°C) indicate?
All of the above
What does uniform smoke from multiple openings indicate?
The fire is in a concealed space or deep-seated
What should firefighters expect if they are engaged in an interior fire attack downwind of a wind-fed fire?
Being overrun by the fire as wind can fan flaming
What does humid climates do to the smoke plume?
Keep the smoke plume tight
What does brown smoke from gable-end vents, eaves, and floor seams indicate?
A warning sign of impending collapse
What does the acronym VVDC stand for in the context of fire behavior and smoke attributes?
Volume, Velocity, Density, Color
What is the main warning sign of a backdraft event?
Puffing and sucking of smoke at doors and windows
What best describes the term 'pyrolysis' in the context of fire behavior?
The chemical breakdown of compounds into other substances by heat alone
What does black fire refer to in the context of fire behavior?
A slang term for smoke that is high-volume, ultra-dense, and deep black
What is the primary role of an ISO (Incident Safety Officer) in reading smoke during a fire incident?
To predict future hostile fire events based on VVDC observations
What does turbulent velocity indicate in the context of reading smoke?
Serious heat and impending flashover
What distinguishes flame-over as a hostile fire event?
The ignition and sustained burning of the overhead smoke layer within a room and/or hallway
What is the main characteristic of an explosive growth phase in hostile fire events?
The rapid growth due to reintroduction of combustion air into a ventilation-controlled fire
What is the primary purpose of reading smoke in relation to firefighting?
To predict future hostile fire events based on volume, velocity, density, and color observations
What does 'ghosting' refer to as a warning sign in hostile fire events?
The intermittent ignition of small pockets of smoke, usually seen as fingers of flame that dance through the upper smoke layer
What is the concept of thermal balance in a building?
It refers to the heat of combustion collecting at the ceiling and cool air flowing to the fire below it.
How does inadequate airflow disrupt thermal balance in a building?
By causing more incomplete combustion and creating denser smoke, disrupting the balance.
What does 'light smoke showing' from a very large building indicate?
A large, dangerous fire inside the building.
What should change in a positive, continuous manner if firefighting efforts are appropriate?
Smoke velocity should gradually slow down.
What should an ISO do if smoke becomes darker and thicker when ventilation fans are used?
Stop using the ventilation fans as they are making conditions worse.
What is positive pressure attack (PPA) used for?
To create a controlled air and exhaust flow path to improve smoke conditions and firefighter safety.
When should an ISO intervene to stop or alter PPA tactics?
When smoke leaving other portions of the building intensifies and becomes darker and thicker.
What three-step process can be used for reading smoke?
View, Analyze, Determine
How does weather affect reading smoke attributes?
"Weather can change each attribute of smoke depending on its severity."
Which attribute should an ISO observe to determine if positive-pressure ventilation (PPV) tactics are helping or hurting fire suppression efforts?
Smoke volume
What does 'sucking', 'puffing', and 'breathing' signs indicate about a fire?
The fire is out of thermal balance.
According to the text, how does thermal balance affect firefighting efforts?
Thermal balance can indicate whether firefighting efforts are succeeding or not.
What is the main purpose of reading smoke for ISOs?
To predict the behavior and potential of the fire
What does thick, black, fast smoke indicate?
Super-hot smoke capable of instant ignition
Which phase of ventilation-controlled fire behavior is often triggered by firefighters opening a door for fire attack?
Explosive growth
What does low-volume white smoke from multiple locations in a large building indicate?
Deep-seated fire within the building
What does yellowish-gray smoke from cracks or seams indicate?
Sulfur compounds present in the fire
What are the factors that affect flow paths and compartmentalized fire growth?
Compartment size and building materials
What is the best solution upon entry for firefighters when facing explosive growth event?
Begin protective cooling of ceilings and walls
What is the main cause of a smoke explosion?
Sudden ignition by sparks
Why has the four-phase fire behavior model become obsolete for building fires?
Because it cannot account for modern compartmentalized fire behavior
What is the primary purpose of reading smoke in predicting fire behavior?
To allow ISOs to predict what the fire will do next
What is the significance of turbulent smoke filling a box?
It indicates a warning sign of impending flashover
How can ISOs refine their read on fire behavior and firefighting effectiveness?
By determining the rate of change of each attribute and looking for positive changes in smoke conditions
What does turbulent smoke that has filled a compartment indicate?
A flashover is imminent.
What does the color of smoke indicate?
The stage of heating and the location of the fire in a building.
What does high velocity and very thin (low density) black smoke indicate?
Flame-pushed fire.
What does thick, laminar-flowing smoke indicate?
The box is still absorbing heat.
What does white smoke emitted when materials are first heated mostly consist of?
Moisture, airborne solids, gases, and aerosols.
What does thick black smoke in a compartment reduce the chance of due to smoke toxicology?
Life sustainability.
What does the density of smoke refer to?
The thickness of the smoke.
What does brown smoke from structural spaces indicate?
Heating of materials.
Test your knowledge of thermal balance in buildings with this quiz. Learn about the concept of heat distribution, boundary layer, and the factors affecting thermal balance.
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