Ch 14. Foam Equipment And Systems Flashcards
What two things must be done to mechanical fire fighting foams before they can be used?
They must be proportioned and aerated
Raw foam liquid and its container that has not been mixed with water and air is known as?
Foam concentrate
Gasoline is an example of a hydrocarbon fuel that can be extinguished using what class of foam?
Class B foam
What class of foam is designed solely for use on hydrocarbon fuels and are not effective on polar solvent products regardless of the concentration that it is applied?
Class B foams
Some foams designed for “polar solvents” may work on “hydrocarbons”, but not vice versa.
What are the two categories of fuels that class B foams maybe used on?
Hydrocarbons and polar solvents
What is the specific gravity of hydrocarbons?
Hydrocarbons have a specific gravity less than one meaning they will float on water.
Polar Sulivant fuels such as alcohol, acetone and ketones Will mix with water. What is the term for these types of liquids?
Miscible fluids. 
Some foams are designed to create a barrier between the fuel and the fire. This method is called?
Separating
Foam extinguishes and or suppresses vapors by what three methods?
Separating, cooling, suppressing or smothering
Most fire fighting foam concentrates are formulated to be mixed with what percentage of water?
94 to 99.9%
FFX foams percentages range from 0.1-6%
What method of foam proportioning uses the pressure of water stream to draft from concentrate into the fire stream?
Induction.
What are the four basic methods of foam proportioning?
Induction, injection, batch mixing, premixing
What foam proportioning method occurs when an appropriate amount of foam concentrate is poured directly into a tank of water?
Batch mixing
What is a major disadvantage of premixing foam concentrate?
Premixed foam is limited to one time use applications
Why should firefighters avoid mixing different types of foam concentrate?
It may result in ineffective Pharma with reduced suppression capabilities
How many gallons are typical foam pails?
5 gallons
How many gallons are typical foam concentrate barrels?
55 gallons
How many gallons are typical bulk storage foam concentrate totes?
275 gallons
What is added to class a foams to reduce the surface tension of water in the foam solution?
Hydrocarbon surfactants
What are the typical class A foam concentrate mix percentages?
0.1 to 1%
Why should direct skin contact be avoided when working with class a foam concentrate?
Class a foam concentrate has a corrosive affect
What is the shelf life for class B foam concentrates that are protein-based?
10 years
What is the shelf life for class B foam concentrates that are synthetic?
20 to 25 years
What is the shelf life of class A foam?
20 years
The drain time for class a foam solutions will increase in proportion with increases in the:
Foam percentage of the solution
Dry foam is most likely used on what type of surface?
Vertical surfaces
What is a characteristic of mixing mil spec foam concentration of the same type?
They may be mixed at any time with no adverse effects
The application rate for a class A foam is the same as:
The minimum required flow rate for water
What is a benefit as a result of the longer drain time of class a foams?
Insulating layer for a longer period of time
What are the standard mixing proportions for class B foam?
1% to 6%
The type of concentrate used, whether or not the fuel is on fire, and whether the fuel is contained or uncontained are variables that affect the foams:
The foams rate of application
Fuel spills should be approached from what position?
Uphill and upwind
What is the formula to calculate the foam application rate available from a specific nozzle based on the involved fire area?
Flow rate devided by area of the fire
Ex. 250gpm
—————
1000 sf. = .25 gpm per sf
What is the most commonly used type of synthetic foam concentrate?
AFFF
What is an in-line foam eductor?
A portable foam proportioner that is designed to be attached directly to the pump panel discharge or connected at some point in the hose lay. 
What happens to foam concentrate when it is heated?
It becomes less viscous
One major advantage of self educting nozzles is that:
The pressure drop is much lower than with most standard foam nozzle educators. This produces a more effective fire stream
What is a jet ratio controller?
A type of in-line doctor that may be used to supply foam concentrate to a self-educting master stream. It allows the foam concentrate supply to be located as far as 3000 feet away from the master stream.
What percentage of concentrate does a jet ratio controller proportion?
66.5% solution
What is the most common type of installed proportioner used in modern fire apparatus?
Around the pump proportioner
What is a major advantage of using variable flow demand type balanced pressure proportioner?
The flow of concentrate matches the pressure demand
AFFF foam solution can act as a cleansing agent. What must be done after using a FFF foam?
Thoroughly flush out the tank and pump to remove all foam, and then check the seals for proper lubrication.
CAFS engines use high energy foam proportioning. How does this positively affect fire streams?
The streams are farther reaching.
When should smoothbore nozzle’s be used in the application of foam?
Only when using class A foams from a CAFS
What is the only nozzle that should be used with flouroprotein concentrates?
Air aspirating foam nozzles
What is a physical feature about water aspirating devices (Nozzles) for foam application?
They are larger and longer
Why would a mechanical blower (nozzle) be the best choice of equipment when an incident requires total flooding?
They produce foam with a very high air content.
What is caused with a nozzle is placed too far above the eductor during form application?
Excessive elevation pressure is created
When would a roll on method of applying foam be effective?
When fuel is ignited in a large, flat ground level surface.
What foam application method might be used at an incident involving an above ground storage tank?
Rain down method
When using a CAFS apparatus, 2 ft.³ per minute of airflow per gallon per minute of foam solution produces a dry foam of up to 100 G p.m. at what expansion ratio?
10:1 expansion ratio
What are the guidelines for the online foam inductor to properly produce foam using the Venturi effect.
-Foam quality may decrease or stop if the gpm exceeds the rated capacity.
-The pressure at the discharge side of the eductor must not exceed 70% of the eductor inlet pressure. This is determined by adding nozzle pressure, friction loss between eductor and nozzle and elevation pressure.
