Transcript The Art of Reading Smoke

The ART of Reading Smoke
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Why “Read” Smoke?
To determine
“HOW MUCH” fire
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Why “Read” Smoke?
To help find the LOCATION of the
fire
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Why “Read” Smoke?
To help predict COLLAPSE potential
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Why “Read” Smoke?
To help PRIORITIZE Strategies &
Tactics
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Why “Read” Smoke?
To PROTECT Firefighters from a
“HOSTILE FIRE EVENT”
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The “ADVANCED” Basics
Concept #1:
“Smoke” IS Fuel
Gases
Aerosols
Particulates
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The “ADVANCED” Basics
Concept #2: Fuels have changed…
Mass and Make-up!
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The “ADVANCED” Basics
Concept #3:
The Fuel has Triggers:
•Flash Point
•Fire Point
•Ignition Temperature
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The Triggers : Temp & Mixture
“Flammable Range / Air Mix”
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Flammable Range & the Three Fires
Too Rich . . .
Too Lean . . .
Just Right . . .
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Yesteryear vs. Today
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Other Prerequisites to Reading
Smoke
You must be able to determine...
• Stage of Fire: Early, Growth, or Late
• Is the “box” absorbing heat? Laminar vs.
TURBULENT flow
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“ HOSTILE ”
Fire Events
• Flashover
• Backdraft
• Smoke Explosion
• Rapid Fire Spread
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FLASHOVER
WARNING SIGNS:
Turbulent Smoke
“Rollover”
Auto Ignition outside
Smoke–Cloud ignition is likely after flashover
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BACKDRAFT
Remember – Backdraft is triggered by O2 being
introduced to pressurized smoke that is
ABOVE it’s ignition temperature
 Yellowish-grey smoke
 Whistling
 Bowing windows
 “Sealed” containers
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SMOKE EXPLOSION
Remember – A Smoke Explosion is a spark or
flame applied to a mixture below its ignition
temperature
 Trapped gases in upper areas
 Growing fire
 Increasing smoke density
 Air intake overtaking smoke exiting
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RAPID FIRE SPREAD
Usually “Container” Influenced
SMOKE is the Fuel that is spreading the fire
Look for fast moving smoke in high pressure
zones
May result from another “event”
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“ Reading Smoke”
Application “RULES”:
Observations are typically made from outside - inside
observations hide the “real” picture.
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“ Reading Smoke”
• Visible FIRE is easy to read - look past it for
the real story
• Compare vent openings
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The ART of Reading Smoke
A PROCESS to help predict fire
behavior and hostile events
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Step 1: Evaluate Key
Attributes
• Volume
• Velocity
(Pressure)
• Density
• Color
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VOLUME
Always
relative to the
“Box”
Tells “how
much” fuel
has offgassed
Sets the
Stage
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VELOCITY (Pressure)
How fast is the
smoke leaving?
Can indicate
volume or heat
Helps find the
location of the
actual fire
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DENSITY
Most Important
Factor
Quality of Burning
Continuity of Fuel
Likelihood of an
Event
“Degree” of the
Event
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COLOR
Rarely tells
“material”
burning
Stage of Heating
Location of Fire
“Brown” Smoke
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“BLACK FIRE”
“Black Fire” is the term
we give to High
Volume, High
Velocity, Extremely
Dense, Black Smoke.
It is the sure sign of
impending flashover
– VENT & COOL
are your only
choices.
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Step 2: Weigh
Factors
• Container (most
important factor)
• Weather
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Step 3: Judge the CHANGE
RATE
Are SMOKE conditions getting better or
worse?
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Predict the EVENT
Consider that:
• One hostile event can - and
usually will - lead to another
event.
• Communicate your observations.
• Warning Signs are not always
visual – use your KNOWLEDGE
and EXPERIENCE.
TRUST YOUR INSTINCTS…
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Some other “Tricks”
WATCH OPEN DOORS!
• Smoke/Air is 50/50: Fire on
same level
• SMOKE doesn’t lift: Fire below
• SMOKE is stagnant or
disappears: Fire Above
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Short Cuts (not absolute)
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Thick/Black/Fast = heat and explosive
Thin/Black/Fast = fire pushed nearby
White w/Speed = hot – but distant
Uniform speed/color from many places =
deep seated
• Brown = unfinished wood being heated – a
collapse warning in lightweight
• Turbulent = Flashover
Be Safe – Make it Safe
For more info, contact Dave Dodson
[email protected]
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