Investigating
Wildfire
Extinguishing
Methods
Helen Stritzel, Carmen Plowman, Juan Torres, Weiliang Sun, Grant Matthews
• How effective are different methods, including type of
suppression and application, of varying flame retardants
used to suppress a fire in an alpine environment?
Testable Question
• If we test different kinds of commonly used fire
retardants, then Monoammonium Phosphate will be the
most effective fire suppression technique because when
dispersed, it cloaks potential fuel sources with a carbon
substance when heated, as opposed to saturating the fuel,
absorbing heat, or extinguishing the flames on a smaller
scale.
Hypothesis
Types of Flame
Retardants
• MAP is a fire retardant, so it is
applied around a wildfire to
contain it
• Aerially distributed in powder
form to forests and brush lands
• Remains effective until
removed manually or by rain
http://www.qrbiz.com/buy_Map-of-the-Ancient-World
Monoammonium
Phosphate
How it Works
1. A cation is released when
Monoammonium Phosphate
is heated
2. The cation reacts with
cellulose from the fuel,
producing an ester.
3. The ester thermally degrades,
releasing water vapor and
carbon that coats the fuel and
renders it fireproof
Monoammonium
Phosphate
http://chemistry.about.com/od/chemistryjokes/ig/Chemistry-Cat/Chemistry-Cat---Cations.htm
• Mechanism
• Mixes with water to
become foam
• Reduces surface tension
of water and allows fuel
to become saturated faster
• Creates a protective foam
blanket around fuel
Phos-Chek WD 881
http://en.wikipedia.org/wiki/Phos-Chek
• Benefits
• Applied aerially
• Is not a significant hazard to human health during its
manufacture or subsequent use.
• Drawbacks
• If deposited into a lake or stream, it could result in a fishkill.
Phos-Chek WD 881
• Mechanism
• Extinguisher filled with pressurized CO2
• Smothers flame, depriving it of oxygen
• By far the most common extinguisher
for small-scale fires
• Safe and reliable
Carbon Dioxide
A CO2 fire extinguisher. Image:
http://frakerfire.com/blog/wpcontent/uploads/2012/09/co2-mri.jpg
• Benefits
• Portable
• No cleanup necessary
• Drawbacks
• Purely small-scale method
• Expensive to store and maintain pressure, especially as volume
increases
• Impractical for wildfire use
Carbon Dioxide
• Mechanism of fire suppression
• Superabsorbent polymer (hydrogel)
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•
•
•
Large molecule with many repeating subunits
“Slurry” – liquid blended with solid (similar to concrete)
Soaks hundreds of times its weight in water
Surrounds w/polymer frame, retaining moisture
• Main Use
• Thermal fire protection (i.e. structural protection)
Thermo Gel Fire
Suppressant
Firefighters spread thermo gel to reduce fire spread.
Image: http://ktar.com/?nid=6&sid=619505
• Benefits
• Can be applied ahead of time to staunch fire spread
• Protects homes and other areas
• Drawbacks
• Difficult cleanup
Thermo Gel Fire
Suppressant
• “Clean Agent”
• Nonconductive
• Volatile (evaporates quickly at room temperature)
• No residue
• Mechanism
• Stops combustion chemically by reacting with the fire’s requisite
fuel and restricting oxygen flow
Halon
A Halon fire extinguisher. Image:
http://upload.wikimedia.org/wikipedia/co
mmons/d/d9/FireExtinguisherABC.jpg
• Benefits
• Clean agent
• Quick and effective
• Drawbacks
• CFC (Chlorofluorocarbon)
Effect of CFCs on the atmosphere. Image:
• Contribute to atmospheric ozone depletion http://www.daviddarling.info/images/chloro
fluorocarbons.gif
• Usage ended in 1994 w/government restrictions
• Relatively small-scale extinguishing technique (may not
apply to wildfires)
Halon
1. The experimenters will set up a controlled mock burn
site created from typical alpine fuel..
2. The fire retardants, MAP, Phos-Chek, and Thermo Gel,
will be applied from a height simulating aircraft
movement, and the fire extinguishers, Halon and
Carbon Dioxide, will be applied to the fire using safe
techniques.
3. The fire will then be set for each trial and the time taken
for the fire to either run out of fuel from being
contained or extinguished using the agents mentioned
about will be recorded.
Proposed Investigation
Variables
• Independent Variable: Type of fire suppressant
• Dependent Variable: The amount of time taken for a set fire to
be extinguished
• Controlled Variables: The type of fuel used in each trial, the
same amount of fuel used and the same surrounding
environment.
Proposed Investigation
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Basic facts about Halon. (n.d.). Retrieved March 11, 2014, from
http://www.h3rcleanagents.com/
support_faq_2.htm
Fire & aviation management. (n.d.). Retrieved March 7, 2014, from
http://www.fs.fed.us/fire/
retardant/
Firefighters say gel works, but don't expect rush to stockpile it. (2007, October 12).
Retrieved
March 10, 2014, from http://ktar.com/?nid=6&sid=619505
Firefighting chemicals. (n.d.). Retrieved March 7, 2014, from http://www.cfs.sa.gov.au/site/
about_us/what_we_do/aerial_firefighting/firefighting_chemicals.jsp
Makowka, N. (n.d.). Wy carbon dioxide (CO2) in fire suppression systems? Retrieved
March 11,
2014, from http://www.nafed.org/whyco2
Phos-check WD-881 Class A foam. (n.d.). Retrieved March 7, 2014, from http://www.phoschek.com.au/foam/phos-chek-wd-881
Phosphate based forest fire retardants. (n.d.). Retrieved March 7, 2014, from http://
www.phosphatesfacts.org/pdfs/Phosphate%20Based%20Forest%20Fire%20Retarda
nts.pdf
Wildland fire chemical products toxicity and environmental concerns general information.
(2007, January). Retrieved March 7, 2014, from http://www.fs.fed.us/rm/fire/documents/
envissu.pdf
Bibliography