4630 Firefighting Foam And Wetting Agents Flashcards
Three ingredients of foam
Foam Concentrate
Water
Air
Foam mixing ratio for 500 gallon tank.
10.8 oz or 1.5 cups
Foam mixing ratio for 1000 gallon tank.
24 ounces or 3 cups
Definition of foam
A stable mass of small air filled bubbles with a lower density / specific gravity than oil, gasoline, alcohol or water.
Class A uses
.5% - 1%
Clings to vertical surfaces
.1% concentrate will be beset used for
Deep seated fires and penetrating needs
.3% concentrate is best used for
Structural firefighting where some vertical cling might be needed
.5% concentrate is best used for
Tire pile fires
1.0% foam will be effective for
Exposure needs on structures and in extreme weather and fire conditions.
How often should class A foam be reapplied?
Every 10 minutes
What is a riparian area?
The interface between land and a river or stream. Foam shall not be used with in 100’ of riparian areas.
What does 3% x 6% foam mean?
3% for hydro carbons
6% for polar solvents
Max GPM for 3% hydrocarbon application
167 GPM
Any more GPM will dilute product to less than 3%
Max GPM for 6% polar solvent application
83 GPM
Any more GPM will dilute product to less than 6%
Why do polar solvents break down class B foam faster?
Polar solvents have an affinity for water, they will extract water from the finished foam by pulling h2o out of the bubble wall.
Re-application of foam is dependent on these factors
Ambient temperature Fuel temperature Active fire Integrity of foam Should be applied every 10 minutes
How should you apply class b foam?
Indirect or banking method
What is AFFF?
Aqueous Film Forming Foam
What is the policy number for
Firefighting Foam and wetting agents
4630
Why are polymers added to class b foam?
Polymers give elasticity, mechanical strength, and water retention capability to foams generated from them. The concentrates also contain dissolved polyvalent metallic salts, which aid in bubble strengthening capability when exposed to heat.
