Foam Flashcards
Types of foam
Low expansion
High expansion
Low expansion foam details
i. Class A (ordinary combustibles/wildland)
ii. Class B (flammable liquids)
1. Protein foam
2. Fluoroprotien foam
3. Film forming flouroprotien foam (FFFP)
4. Aqueous film forming foam (AFFF) (Low expansion mechanical foam)
5. AFFF with Alcohol Resistant Concentrate (ARC) or Alcohol Type Concentrate (ATC)
6. Micro-Blaze Out
Types of fuel requiring foam application
hydrocarbons and polar solvants
Hydro carbon fuel facts
i. Floats on water
ii. Hydrophobic
iii. Gasoline, kerosene, fuel oil, benzene, naphtha, jet fuel, crude oil
iv. Typically give off black smoke
Polar solvents fuel facts
i. Hydrophilic
ii. Alcohols, acetones, lacquer thinners, ketones, esters, acids, isopropyl
iii. Usually burns cleaner than hydrocarbons
iv. Flame is sometimes not visible
How does the foam work?
a. Smothering- preventing air and flammable vapors from combining
b. Separating – intervening between the fuel and the fire
c. Cooling – water in the foam lowers the temperatures of fuel and adjacent surfaces
d. Suppressing – preventing the release of flammable vapors
Why do we use foam
a. Many agents can extinguish a class B fire, however, foam provides
i. Firefighter safety
ii. Prevention of fuel ignition or re-ignition
iii. Suppression of flammable vapors
iv. Post fire security
What is surface tension?
a. The ability of water to bind together
b. Foam will decrease the surface tension and allow the foam to float on top
Type of incidents that require foam
a. Tank truck rollovers
b. Tank car derailments
c. Fuel spills at an automobile accident
d. Chemical spills
e. Spills of paint, motor oil, lacquer thinner, and other flammable liquids stored in warehouses and department stores.
What is foam not effective on?
a. Class C electrical fires
b. Pressurized gas
c. Combustible metals
Foam generation (five things you need for foam)
a. Foam concentrate
b. Foam proportioner (55psi friction loss)
c. Foam solution
d. Aeration
e. Finished foam
Foam tetrahedron
a. Foam concentrate
b. Water
c. Air
d. Mechanical agitation
Foam is generated by:
a. Mixing foam concentrate with water to make a foam solution
b. Mechanical agitation occurs as water and foam concentrate pass through hose
c. Aeration of the foam solution as it leaves the nozzle or is introduced before leaving the nozzle, making finished foam.
Does foam last forever?
- Finished foam doesn’t last forever. As foam drains, it becomes dry. Dry foam looks the same but allows for the release of vapors. Dry foam is also called skeletal foam. The bigger expansion, the slower the drainage
Foam application techniques
a. Bounce off
b. Bank in
c. Lofting/rain down
d. NO PLUNGE!