the art of reading smoke bill godfrey, fire chief deltona fire department adapted from material...
TRANSCRIPT
The Art of Reading
Smoke
Bill Godfrey, Fire ChiefDeltona Fire Department
adapted from material developed by:
Dave Dodson, Battalion Chief (Ret.)
Updated: April 19, 2023
Why Read Smoke? It helps…
Determine how much fire Find location of fire Predict collapse potential Protect firefighters from hostile fire events Prioritize strategy and tactics
Brown/Tan smoke
Unfinished wood is burning Engineered wood products
Woodchips Glue (breaks down 400° F)
Coming from structural space? Floor, attic, crawl, etc. Lost integrity
What is Smoke? Components
Aerosol Suspended liquids Lots of oils
Particles Gas
Carbon monoxide (CO) Transient and Trace
(TNT)
“Stinky” car fire Dirty carbon
CHEMICAL COMPONENTS OF SMOKE (Burnsurgery.org ¶4)
COMPOUNDS SOURCE
- AMMONIA- SULFUR DIOXIDE- CHLORINE
CLOTHING, FURNITURE, WOOL, SILK
- HYDROGEN CHLORIDE- PHOSGENE
PLYVINYL CHLORIDE,FURNITURE, (WALL, FLOOR COVERINGS)
- ACETALDEHYDE- FORMALDEHYDE- ACROLEIN
WALL PAPERLACQUERED WOODCOTTON, ACRYLIC
- CYANIDE- CARBON MONOXIDE
POLYURETHANE -- UPHOLSTERYNYLON (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. Smoke is fuel
2. Fuel has changed
3. Fuel has triggers (properties)
4. Fuel events (hostile) have a limited range
#2: Fuel Has Changed Natural → synthetic
Higher off-gassing
High mass → high surface-to-mass More surface to burn Heats quicker Loses integrity faster
#3: Fuel Has Triggers
IFSTA. Essentials of Fire Fighting Second Edition. Stillwater: International Fire Service Training Association, 1983.
Can lead to hostile fire event
Properties Flammability range Ignition temperature
#4: Fuel Has a Limited Range
Smoke Too lean: white, puff Too rich: black, thick Just right: fireball
Propane Flash point -44° F Flammable range 2%-9%
Carbon Monoxide (CO) Flammable range? Ignition temperature?
3 Things You Need to Know Stage of fire
development? Early, middle, or late
How much heat can the “box*” absorb? 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
Auto ignition Rapid Fire Progression
Flashover Backdraft Smoke explosion
Auto Ignition (Vent-Point Ignition)
Smoke Turbulent flow Usually dark or black
Can be white, light Dense, thick Significant volume
Ignites spontaneously Then goes out Mixture not right
Usually too rich, insufficient Oxygen
Auto Ignition (Vent-Point Ignition)
Smoke Turbulent flow Usually dark or black
Can be white, light Dense, thick Significant volume
Ignites spontaneously Then goes out Mixture not right
Usually too rich, insufficient Oxygen
Flashover Transition Period (event)
Rapid Fire Progression
Flashover Transition Period (event)
Start Ceiling temperature 1112°F (600°C) Floor heat flux 20 kW/m2/sec (0.5
cal/cm2/sec) All fuels pyrolyse Sudden and sustained growing fire
Ceiling temperature 1832°F (1000°C)
Floor heat flux 170 kW/m2/sec (4 cal/cm2/sec) 347-1292°F (175-700°C)
End Fully developed fire
Flashover Demystified
Exterior Flashover Indicators
3 External signs 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 Oxygen controlled fire Smoke pressurized in a
confined space with Heat No oxygen Gases above ignition
temperature Trigger is oxygen Smoke
Not really puffing, might see surges
Smoke Explosion
Heated gases, right mixture Needs spark or flame
Pockets of gas get trapped Typically high Ceilings
Trigger is spark or flame 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
Outside function Not about reading
flames Visible fire easy to read Don’t stare at flames
About comparing Must see multiple
openings Openings without smoke
just as important
4 Step Process
Step 1: Evaluate key factors Volume, velocity, density, color
Step 2: Weigh factors Step 3: Getting better or worse Step 4: Predict the event
Step 1: Evaluate Key Factors
Volume, Velocity (how much pressure) 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.)
Density – how thick is the smoke? Incomplete burning
How much fuel is in the smoke?
Thicker the smoke More likely hostile fire
event More deadly (Cherry
Rd) DC Engine Co: “Heavy smoke, ‘0’ visibility, extremely hot, no fire”
http://fire.nist.gov/6510/6510.htm
Step 1: Evaluate Key Factors (cont.)
Color Natural (unfinished wood): tan/brown smoke Synthetic: white → gray → black
Tells how fuel is being heated Early: off gases white (moisture) Late: off gases black (high heat, open flame)
Black smoke, high heat → fire Gives up carbon as travels Heats fresh fuels, give up moisture → white smoke
Step 2: Weigh Factors
Container (“box”) Bedroom or Home Depot
Fire’s oxygen supply Fuel controlled vs. Oxygen controlled Thermal balance Air pathways
Unintentional Ventilation
Step 2: Weigh Factors (cont.)
Weather Hot/humid Hot/dry Cold/humid Cold/dry Implication
Cold → straight up → hot fire Hot/dry → smoke hangs out → cooling smoke??
Firefighting efforts Volume, velocity, density, color → all 4 in 30 sec
Step 3: Getting Better or Worse?
Stable/predictable Not a lot of time reading smoke
Rapidly changing/predictable …enough to make sure we’re right
Unstable/unpredictable Volume, velocity, density, color not making sense Keep reading Be very careful Be defensive minded Vent
Step 4: Predict the Event
Trust instinct If something isn’t
right… …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
3. 5-second change in smoke conditions Outward movement
• event has happened Inward movement
• about to happen
CASE Study:
Volume/Velocity/Density Color: Comparison of Openings: Impression of the Fire: Location of the Fire: Next Event:
