Ch. 6 Flashcards
What are the 2 sources of smoke
Incomplete Combustion
Pyrolitic Decomp
What is pyrolysis
Chemical break down of compounds
What does pyrolysis often lead to
Combustion
What does most of the smoke from a building come from
Pyrolysis
What does a heat sink absorb heat based on
Composition
Surface to mass ratio
What term is often used for pyrolysis
Off gassing
What are the prevalent solids in smoke
Soot
Ash
What is soot
Carbon
What is ash
Metals
Minerals
What color does carbon ad to a fire
Flat black
What color does ash ad to a fire
Dirty white
What are other solids in fire
Dust
Fibers
Pulp
What is a propelled or suspended liquid
Aerosol
What is a by product of combustion and pyrolysis
Water Vapor
Hydrocarbons produce what smoke color
Wet black
What is the minimum temp hydrocarbons will ignite
450
What gasses affect fire behavior
CO HCN Acrolein Hydrogen Sulfide Benzene
What is the collective flammable percent range of smoke
1-74%
What products does complete combustion of materials render
Heat
Light
Co2
Water Vapor
What triggers smoke to ignite
Temp
Mixture
What is a piloted ignition
Spark
What are the 4 stages of fire
Ignition
Growth
Fully developed
Decay
What are smoke paths generally influenced by
Interior Geometry
Opening to exterior
What are the 6 phases of ventilation controlled fires
Ignition Initial growth Ventilation Limit Explosive Growth Fully Developed Decay
What phase does pyrolysis begin
Initial growth
What is a proactive solution to prevent the explosive growth phase
Protective cooling
What is the explosive growth phase a combination of
Flash over
Flame over
What is the intermittent lighting of smoke pockets called
Ghosting
Ghosting is a warning sign of
Flash over
What is the ignition and sustained burning of overhead smoke called
Flame over
Where does flame over typically orginate
Seat of the fire
What event happens when materials reach their ignition point simultaneously
Flash over
What fire event happens when air is reintroduced into a space
Backdraft
How long is a volume shift in a back draft
10-90sec
What does a backdraft sound like
Denotation
What is an indicator of built up pressure in a building
Smoke Velocity
What are the 4 characteristics of smoke
Volume
Velocity
Density
Color
What 2 forces cause smoke to pressurize
Convection Heat
Smoke Volume
How does smoke move when it contains heat
Fast
What are the 2 types of smoke
Turbulent
Laminar
What causes turbulent smoke
Serious heat
What is the most important smoke observation
Velocity is turbulent or laminar
What does turbulence smoke indicate
Flashover environment
What does laminar smoke indicate
Box is absorbing heat
What does the thickness of smoke indicate
How much fuel
What is most smoked caused by
Pyrolysis
What does smoke color indicate
Heat
Location
What color is smoke from natural unfinished materials
Tan
What is the smoke color from synthetic or painted materials
Gray
What color is smoke from unfinished wood
Brown
What does brown smoke indicate
Significant heat
What does black fire indicate
Autoignition
What temps can black fire reach
Over 1000°
What changes the appearance of smoke
Weather
Thermal Balance
Container Size
Firefighting
What are the 3 steps of reading smoke
View
Analyze
Determine
Plastic adds what product to smoke
Hydrocarbons
White smoke contains mostly
Moisture
What causes the explosive growth phase
Opening of more doors
What events are the explosive phase a result of
Flame over
Flash over
What does black smoke mean
Open flaming is near by
What is most of the smoke coming from at a typical building fire
Materials breaking down without burning. Pyrolysis
What are surfaces that are burning doing
Off-aggregating
What can soot support
Flaming
What are flow paths divided in to
Air track
Exhaust
What is the decay phase also called
Fuel limited phase
What happens when the room can no longer absorb heat and reflects radiant energy back onto itself
Flashover
What is a dangerously late warning sign
Sensation of heat
What does uniform smoke indicate
Concealed or deep seated
What weather condition allows smoke to dissipate more easily
Low humidity
What does sucking, puffing and breathing indicate
Fire is out of thermal balance
Low lying smoke in a sprinklered building indicates
Fire is not being controlled by sprinklers
What type of materials are solids suspended in smoke
High surface to mass
What is the volumetric composition of smoke
Particulate matter
What are the primary liquids in smoke at a structure fire
Moisture
Hydrocarbons
What are the surfaces that are smoking releasing
Particulates
Aerosols
Gases
What event can be delayed by opening a door or window
Explosive growth
Where do smoke explosions typically occur
Trapped smoke area
What color of smoke do solid materials emit when first heated
White
