WELCOME TO THE MICT SETA STAKEHOLDER ROADSHOW 6 February 2014
Fire Behavior Understanding the Basics Pat Hultman FF/MICT/LEO-AAS Training Officer.
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Transcript of Fire Behavior Understanding the Basics Pat Hultman FF/MICT/LEO-AAS Training Officer.
Learning Outcomes
• List different types of Extreme Fire Behavior
• Differentiate between Fuel and Air controlled fires
• Understand the importance of reading smoke and fire
• Appreciate the dangers assosciated in regards to extreme fire behavior
Why this matters
• In 2007, 20 LODD due to Extreme Fire Behavior. Plus numerous close calls.
Video 4.5 min. !!!1:41!!!
Fire Gases and Pyrolisis• Common Fire Gases
– CO– HCN– Hydro Carbons
• Methane • Propane
• Pyrolisis– Decomposition by heat– ↑ build up of combustible
gases– Where does the heat come
from?
Heat Transfer
• Conduction– Direct transfer through contact
• Convection– Transfer through a medium such as air,
H2O, etc
• Radiation– Transfer in the form of light energy
Understanding Radiant Heat• Is radiant heat visible?• At 900° F visible
• Heat Release Rate– Cigarette 5w– Wastebasket 50-150 KW– Pool of Gasoline (2 QTS)
1MW– Sofa 1-3 MW
• Direct Summer Sun– 1kw/m² 100° F Surface
• No Pain
• Near Proximity to Fireplace– 10kw/m² 200-300° F Surface
• 2° Burns ≤ 10Sec• Scorching of and Melting of
• Adjacent to flames– 50 kw/m² 800° F Surface– Autoignition of nearly all
materials in ≤ 5 sec
The avg residential fire will double in size every 15-30 secs
Limits of Flamability
• LFL/UFL
• What are some materials you can think of?• Propane 2.1-9.5% Ideal 4%• Gasoline 1-6%• Acetylene 2.5-80%• CO 12.5-74% What is this in PPM (move decimal
right add 3 zeros)
• Think about the CGI– We know we are immersed in flammable gases
when going into a fire
The Neutral Plane
• Two Separate Layers– Hot Buoyant Combustible gas
• Major source of radiant heat
– Cooler, cleaner
• Commonly discussed as thermal layering (Discussed More Later)
Fire Progression• Stages of Fire
– Phase 1• Incipient and Growth
Stage– What is happening?– What is the next
phase?
– Phase 2• Flashover• What happened?• Auto-ignition temp
– What is the significance?
» Transition From Room and Contents
– Phase 3• Fully Developed
– Phase 4• Decay Stage
• What is a significant threat at this stage?
Extreme Fire Behavior
• Smoke Explosion• Flame Over• Flash Fire
• Fire Gas Ignitions• Flashover• Back Draft
The Firefighter must remain ever vigilant of the conditions around them
These are not some strange uncontrolled phenomenen.
There are key things to watch for both inside on the knob and outside as IC.
Flashover
• Sudden and Sustained transition from a developing fire to a fully developed fire.
• 2/3rds of the heat is radiated down from the neutral plane
Video 1:01
Signs and Symptoms of Flashover
• Ventilated Fire• Painful Radiant Heat (forces you down)• Hot Surfaces (Conduction)• Lowering Neutral Plane
– Fingers of flame – Dancing angels
• Increased Pyrolisis• Increased turbulence of smoke and flame
Back Draft
• The spontaneous ignition of combustible fire gases.
• What are some cause? Why?– Gases at auto ignition temperature– Lack of OxygenPyrolisis will continue to occur until
sufficient cooling
Video 0:44
Signs and Symptoms of Back Draft
• No or limited ventilation
• Lack of visible or blue flame
• Thick rolling black, yellow, or white smoke
• Smoke Pulsating/Whistling
Point of No return
• 5 feet (Chief Dunn)
• Burns– 1° @ 118° F– 2° @ 131° F– 3° @ 152° F
– Heat Output» Trash Can Fire
Methods of Extinguishment
• Direct vs. Indirect– Smooth Bore vs. Fog
• Gas Cooling– Can disrupt neutral plane – Use small fine droplets in short bursts to
minimize
– How much water in GPM for a 19x16 MBR» 300 ft² approx » Round Up to 375 ft² or 3000 ft³ for chart» NFA- 125 GPM» Iowa – 30 GPM» 3D- 75 GPM
Case Study
• April 16 2007
• 24 Y/O Kyle Robert Wilson 2 yrs exp.
• 0604 AM
• Weather- 25 MPH sustained