Foam Flashcards
Fire Tetrahedron
Fuel, Oxygen, Heat, Chemical Chain Reaction
Proportion rates for Class A foam
0.2% for overhaul, 0.5% for fire attack, 1.0% exposure protection
What type of nozzle should be used with CAFs and why?
Use a solid bore nozzle for greater reach and penetration. Fog nozzle will strip some of the air from the foam and have a reduced reach
What is slug flow?
Not enough foam concentrate injected into the stream. Presents as a rapidly pulsating hose line caused by alternating slugs of air and water without enough foam concentrate.
What is a hydrocarbon fire?
Gasoline or diesel
What is a polar solvent fire?
Alcohol-based
What type of Class B foam is predominantly used in the fire service?
AFFF - Aqueous Film-Forming Foam. It forms a film on the surface of the liquid fuel and excludes the oxygen.
NFPA recommendation for foam and water supply
15-minute supply before any fire attack
Proportion rates for Class B foam
3% for hydrocarbons, 6% for polar solvents
Novacool can be used on which types of fires?
Class A, B, D, and K fires
How does Novacool work?
It is an emulsifier, it mixes with the product and renders it inert or unable to burn.
Proportion rates for Novacool
0.1% for overhaul/wildland, 0.4% for fire attack
3/2/1 rule of portable foam eductor
Nozzle must be within 300 feet of the eductor. PDP must be 200 psi at the eductor. 95 GPM nozzle
Proportion rates for Novacool and portable foam eductor
0.5%
Type of air compressor in a CAF system
Rotary air compressor
Advantages of CAF foam
Better reach, Durable air bubbles, Resists heat longer, Reach from a greater distance, Lines are lighter and more durable
Disadvantages of CAF foam
Price and maintenance costs, erratic hose lines if inadequate foam or burst section, additional training
Critical Application Rate of CAF
30-40% of plain water
Two types of flow meters/foam pump/proportioner
FoamPro or Husky
Air compressor capacity in a CAF system
200 SCFM (Standard Cubic Feet per Minute) at 160 psi
What should the air pressure be when in Foam mode on a CAF system?
120 psi
Manufacturer recommended differential between incoming and outgoing pressure on CAF system?
50 psi
Why the pressure differential requirement for a CAF system?
A “zero net” difference does not allow the cooling water to circulate, eventually leading to the compressor overheating.
How to create dry foam in a CAF system
Gate down the discharge valve slightly, reducing the water and increasing the air.
FoamPro pump capacity
2.6 gpm
Husky 10 system capacity
12 gpm
Critical Application Rate for hydrocarbons
0.1 GPM/ft2
Critical Application Rate for polar solvents
0.2 GPM/ft2
Max height from eductor to bucket
6 feet
