Class B Foam Flashcards
What pumpers and ladders are equipped with built in foam eductor systems and a 20 gallon Class B foam tank?
1988-2000
They achieve a rated flow with an inlet pressure of 200psi with how many gpm nozzle?
95 gpm nozzle
The metering valve has five notched settings which are?
0, 1/2, 1, 3 and 6% marks
How do you change the metering %?
Push knob in and align with the desired % then release the knob
May have to pull the knob out if it does not pop out
Foam should start flowing from what psi?
125-200psi PDP
What are the steps to flush the foam system properly?
- Reduce pump psi to 100 or less
- Close the foam valve
- Open flush valve and small 1/4 in foam drain/metering flush valve
- Flush for 5 to 10 min or until the water is clear
- Close 1/4 in foam drain/metering flush valve
- Close eductor valve and flush valve
- Close foam water discharge valve
What class B foam do pumpers and ladders use?
3% / 6% Ansulite AFFF B foam
What foam does crash units use?
3% class b foam
Can you mix foams together?
NO!
What might happen if class a and class b foam are mixed together in a system?
The foam will gel and plug all components making the foam system inoperable
What are some reasons an eductor may fail?
- metering knob not pulled out
- foam handle not pulled out all the way
- nozzle not 95gpm
- foam tank empty
- ball valve stuck (call maintenance)
- partially closed nozzle (need 95gpm)
- hose lay too long
- clogged nozzle
- foam tank not vented
- kink in hose
- metering valve clogged with dry foam
- too much nozzle elevation
Uses for class b foam
- Vapor suppression for liquid spills to prevent ignition or to extinguish fire
- extinguish vehicles and rail cars
- refineries and chemical plants
- facilities with flammable liquids
- production of textiles, drugs and other products
What is low expansion foam best suited for?
Fire attacks on class b fires. It provides penetration power and rapid extinguishment
What is a fog nozzle with a foam aeration attachment best suited for?
Applying a foam blanket
