The Art of
Reading
Smoke
Bill Godfrey, Fire Chief
Deltona Fire Department
adapted from material developed by:
Dave Dodson, Battalion Chief (Ret.)
Updated: 9 April 2015
Why Read Smoke? It helps…
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Determine how much fire
Find location of fire
Predict collapse potential
Protect firefighters from hostile fire events
Prioritize strategy and tactics
Brown/Tan smoke
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Unfinished wood is burning
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Engineered wood products
 Woodchips
 Glue (breaks down 400° F)
Coming from structural space?
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Floor, attic, crawl, etc.
Lost integrity
What is Smoke?
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Components
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Aerosol
 Suspended liquids
 Lots of oils
Particles
Gas
 Carbon monoxide (CO)
 Transient and Trace
(TNT)
“Stinky” car fire
Dirty carbon
CHEMICAL COMPONENTS OF SMOKE
COMPOUNDS
(Burnsurgery.org ¶4)
SOURCE
- AMMONIA
- SULFUR DIOXIDE
- CHLORINE
CLOTHING, FURNITURE,
WOOL, SILK
- HYDROGEN CHLORIDE
- PHOSGENE
PLYVINYL CHLORIDE,
FURNITURE, (WALL,
FLOOR COVERINGS)
- ACETALDEHYDE
- FORMALDEHYDE
- ACROLEIN
WALL PAPER
LACQUERED WOOD
COTTON, ACRYLIC
- CYANIDE
- CARBON MONOXIDE
POLYURETHANE -UPHOLSTERY
NYLON (ANY
COMBUSTIBLE
SUBSTANCE)
Burnsurgery.org. “Upper Airways Obstruction from Tissue Edema.” Burnsurgery.org (2000): 1 page. Accessed April 27, 2003
<http://www.burnsurgery.org/Betaweb/Modules/pulmonary/sec3.htm>.
Key Concepts
1.
2.
3.
4.
Smoke is fuel
Fuel has changed
Fuel has triggers
(properties)
Fuel events (hostile)
have a limited range
#2: Fuel Has Changed
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Natural → synthetic
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Higher off-gassing
High mass → high
surface-to-mass
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More surface to burn
Heats quicker
Loses integrity faster
#3: Fuel Has Triggers
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Can lead to hostile fire
event
Properties
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Flammability range
Ignition temperature
IFSTA. Essentials of Fire Fighting Second Edition. Stillwater: International Fire Service Training Association, 1983.
#4: Fuel Has a Limited Range
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Smoke
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Propane
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Too lean: white, puff
Too rich: black, thick
Just right: fireball
Flash point -44° F
Flammable range 2%-9%
Carbon Monoxide (CO)
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
Flammable range?
Ignition temperature?
3 Things You Need to Know
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Stage of fire
development?
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How much heat can
the “box*” absorb?
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Early, middle, or late
Laminar smoke flow
Turbulent (rolling,
boiling) smoke flow
Is the fire in thermal
balance?

Heat is going up and
out, cool air (oxygen) in
*Box: room or containment area of the fire; not describing the entire building (unless fully involved)
Hostile Fire Events
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Auto ignition
Rapid Fire Progression
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Flashover
Backdraft
Smoke explosion
Auto Ignition (Vent-Point
Ignition)
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Smoke
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Turbulent flow
Usually dark or black
 Can be white, light
Dense, thick
Significant volume
Ignites spontaneously
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Then goes out
Mixture not right
 Usually too rich,
insufficient Oxygen
Auto Ignition (Vent-Point
Ignition)
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Smoke
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Turbulent flow
Usually dark or black
 Can be white, light
Dense, thick
Significant volume
Ignites spontaneously
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Then goes out
Mixture not right
 Usually too rich,
insufficient Oxygen
Flashover
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Transition Period (event)
Rapid Fire
Progression
Flashover

Transition Period (event)
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Start
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Ceiling temperature 1112°F (600°C)

Floor heat flux 20 kW/m2/sec (0.5
cal/cm2/sec)
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All fuels pyrolyse
Sudden and sustained growing fire
 Ceiling temperature 1832°F
(1000°C)
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Floor heat flux 170 kW/m2/sec (4
cal/cm2/sec)

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347-1292°F (175-700°C)
End
Fully developed fire
Flashover Demystified
Exterior Flashover Indicators
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3 External signs
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Turbulent smoke
Usually dark or black
 Color not a reliable
indicator of danger
 Can be white, light gray
Auto ignition
Rollover
Too little GPM can
ignite smoke cloud
Remember this picture…
Berkeley County, SC
Lt. Tom Jurgensmeyer, of the Whitesville Fire Department and Berkeley County EMT, was critically injured during a live fire training burn in
Berkeley County. He received 26% 2nd and 3rd degree burns to his neck, arms, back and hands.
Backdraft
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Oxygen controlled fire
Smoke pressurized in a
confined space with
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Heat
No oxygen
Gases above ignition
temperature
Trigger is oxygen
Smoke
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Not really puffing, might see
surges
Smoke Explosion
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Heated gases, right mixture
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Pockets of gas get trapped
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Needs spark or flame
Typically high
Ceilings
Trigger is spark or flame
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Smoke explosion (Sutherland 3-9)
Sutherland, B.J., and Fleishmann, C. “Smoke Explosions.” Firetactics.com University of Canterbury, School of Engineering
(1999): 79 pages. Accessed April27, 2003 <http://www.firetactics.com/Smoke,%20Sutherland.pdf>.
Reading Smoke
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Outside function
Not about reading
flames
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Visible fire easy to read
Don’t stare at flames
About comparing
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Must see multiple
openings
Openings without smoke
just as important
4 Step Process
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Step 1: Evaluate key factors
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Volume, velocity, density, color
Step 2: Weigh factors
Step 3: Getting better or worse
Step 4: Predict the event
Step 1: Evaluate Key Factors
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Volume, Velocity (how much pressure)
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Full “box” (volume caused)
 immediately slows down on hitting exterior
Hot fire (heat caused)
 Turbulent smoke
 Continues moving fast until cooling in atmosphere
How much pressure? How fast out of openings?
 Fastest near fire
 Further away, slower the smoke
Step 1: Evaluate Key Factors
(cont.)
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Density – how thick is
the smoke?
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Incomplete burning
 How much fuel is in the
smoke?
Thicker the smoke
 More likely hostile fire
event
 More deadly (Cherry
Rd)
http://fire.nist.gov/6510/6510.htm
DC Engine Co: “Heavy smoke, ‘0’
visibility, extremely hot, no fire”
Step 1: Evaluate Key Factors
(cont.)
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Color
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Natural (unfinished wood): tan/brown smoke
Synthetic: white → gray → black
Tells how fuel is being heated
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Early: off gases white (moisture)
Late: off gases black (high heat, open flame)
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Black smoke, high heat → fire
 Gives up carbon as travels
 Heats fresh fuels, give up moisture → white smoke
Step 2: Weigh Factors
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Container (“box”)
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Bedroom or Home Depot
Fire’s oxygen supply
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Fuel controlled vs. Oxygen controlled
Thermal balance
Air pathways
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Unintentional
Ventilation
Step 2: Weigh Factors (cont.)
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Weather
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Hot/humid
Hot/dry
Cold/humid
Cold/dry
Implication
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Cold → straight up → hot fire
Hot/dry → smoke hangs out → cooling smoke??
Firefighting efforts
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Volume, velocity, density, color → all 4 in 30 sec
Step 3: Getting Better or
Worse?
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Stable/predictable
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Rapidly changing/predictable
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Not a lot of time reading smoke
…enough to make sure we’re right
Unstable/unpredictable
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Volume, velocity, density, color not making sense
Keep reading
Be very careful
Be defensive minded
Vent
Step 4: Predict the Event
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Trust instinct
If something isn’t
right…
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…then something isn’t
right!!
Some other little Tips:
1. If visibility is bad, stop and shine a light –
what is the smoke doing?
2. Smoke comes out, stops, then goes back in
Fire hit fuel, making run
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3. 5-second change in smoke conditions
Outward movement
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•
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event has happened
Inward movement
•
about to happen
CASE Study:
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Volume/Velocity/Density Color:
Comparison of Openings:
Impression of the Fire:
Location of the Fire:
Next Event:
Questions?
Thank You!
Contact Information
bill.godfrey@futurefd.com
Cell (407) 402-5533