Investigating Wildfire Extinguishing Methods Helen Stritzel, Carmen Plowman, Juan Torres, Weiliang Sun, Grant Matthews

Testable Question How effective are different methods, including type of suppression and application, of varying flame retardants used to suppress a fire in an alpine environment?

Hypothesis 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.

Types of Flame Retardants

Monoammonium Phosphate 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

Monoammonium Phosphate 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 How it Works

Phos-Chek WD 881 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 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 fish- kill.

Carbon Dioxide 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 A CO2 fire extinguisher. Image: content/uploads/2012/09/co2-mri.jpg

Carbon Dioxide Benefits Portable No cleanup necessary Drawbacks Purely small-scale method Expensive to store and maintain pressure, especially as volume increases Impractical for wildfire use

Thermo Gel Fire Suppressant Mechanism of fire suppression Superabsorbent polymer (hydrogel) 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) Firefighters spread thermo gel to reduce fire spread. Image:

Thermo Gel Fire Suppressant Benefits Can be applied ahead of time to staunch fire spread Protects homes and other areas Drawbacks Difficult cleanup

Halon “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 A Halon fire extinguisher. Image: mmons/d/d9/FireExtinguisherABC.jpg

Halon Benefits Clean agent Quick and effective Drawbacks CFC (Chlorofluorocarbon) Contribute to atmospheric ozone depletion Usage ended in 1994 w/government restrictions Relatively small-scale extinguishing technique (may not apply to wildfires) Effect of CFCs on the atmosphere. Image: fluorocarbons.gif

Proposed Investigation 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 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. Variables

Bibliography Basic facts about Halon. (n.d.). Retrieved March 11, 2014, from Fire & aviation management. (n.d.). Retrieved March 7, 2014, from Firefighters say gel works, but don't expect rush to stockpile it. (2007, October 12). Retrieved March 10, 2014, from Firefighting chemicals. (n.d.). Retrieved March 7, 2014, from about_us/what_we_do/aerial_firefighting/firefighting_chemicals.jsphttp:// Makowka, N. (n.d.). Wy carbon dioxide (CO2) in fire suppression systems? Retrieved March 11, 2014, from Phos-check WD-881 Class A foam. (n.d.). Retrieved March 7, 2014, from chek.com.au/foam/phos-chek-wd-881http:// Phosphate based forest fire retardants. (n.d.). Retrieved March 7, 2014, from nts.pdf Wildland fire chemical products toxicity and environmental concerns general information. (2007, January). Retrieved March 7, 2014, from envissu.pdfhttp://