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IFSTA Exam Prep > Ch 14. Foam Equipment And Systems > Flashcards

Ch 14. Foam Equipment And Systems Flashcards

1
Q

What two things must be done to mechanical fire fighting foams before they can be used?

A

They must be proportioned and aerated

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2
Q

Raw foam liquid and its container that has not been mixed with water and air is known as?

A

Foam concentrate

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3
Q

Gasoline is an example of a hydrocarbon fuel that can be extinguished using what class of foam?

A

Class B foam

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4
Q

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?

A

Class B foams

Some foams designed for “polar solvents” may work on “hydrocarbons”, but not vice versa.

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5
Q

What are the two categories of fuels that class B foams maybe used on?

A

Hydrocarbons and polar solvents

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6
Q

What is the specific gravity of hydrocarbons?

A

Hydrocarbons have a specific gravity less than one meaning they will float on water.

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7
Q

Polar Sulivant fuels such as alcohol, acetone and ketones Will mix with water. What is the term for these types of liquids?

A

Miscible fluids. 

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8
Q

Some foams are designed to create a barrier between the fuel and the fire. This method is called?

A

Separating

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9
Q

Foam extinguishes and or suppresses vapors by what three methods?

A

Separating, cooling, suppressing or smothering

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10
Q

Most fire fighting foam concentrates are formulated to be mixed with what percentage of water?

A

94 to 99.9%

FFX foams percentages range from 0.1-6%

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11
Q

What method of foam proportioning uses the pressure of water stream to draft from concentrate into the fire stream?

A

Induction.

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12
Q

What are the four basic methods of foam proportioning?

A

Induction, injection, batch mixing, premixing

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13
Q

What foam proportioning method occurs when an appropriate amount of foam concentrate is poured directly into a tank of water?

A

Batch mixing

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14
Q

What is a major disadvantage of premixing foam concentrate?

A

Premixed foam is limited to one time use applications

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15
Q

Why should firefighters avoid mixing different types of foam concentrate?

A

It may result in ineffective Pharma with reduced suppression capabilities

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16
Q

How many gallons are typical foam pails?

A

5 gallons

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17
Q

How many gallons are typical foam concentrate barrels?

A

55 gallons

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18
Q

How many gallons are typical bulk storage foam concentrate totes?

A

275 gallons

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19
Q

What is added to class a foams to reduce the surface tension of water in the foam solution?

A

Hydrocarbon surfactants

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20
Q

What are the typical class A foam concentrate mix percentages?

A

0.1 to 1%

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21
Q

Why should direct skin contact be avoided when working with class a foam concentrate?

A

Class a foam concentrate has a corrosive affect

22
Q

What is the shelf life for class B foam concentrates that are protein-based?

A

10 years

23
Q

What is the shelf life for class B foam concentrates that are synthetic?

A

20 to 25 years

24
Q

What is the shelf life of class A foam?

A

20 years

25
Q

The drain time for class a foam solutions will increase in proportion with increases in the:

A

Foam percentage of the solution

26
Q

Dry foam is most likely used on what type of surface?

A

Vertical surfaces

27
Q

What is a characteristic of mixing mil spec foam concentration of the same type?

A

They may be mixed at any time with no adverse effects

28
Q

The application rate for a class A foam is the same as:

A

The minimum required flow rate for water

29
Q

What is a benefit as a result of the longer drain time of class a foams?

A

Insulating layer for a longer period of time

30
Q

What are the standard mixing proportions for class B foam?

A

1% to 6%

31
Q

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:

A

The foams rate of application

32
Q

Fuel spills should be approached from what position?

A

Uphill and upwind

33
Q

What is the formula to calculate the foam application rate available from a specific nozzle based on the involved fire area?

A

Flow rate devided by area of the fire

Ex. 250gpm
—————
1000 sf. = .25 gpm per sf

34
Q

What is the most commonly used type of synthetic foam concentrate?

A

AFFF

35
Q

What is an in-line foam eductor?

A

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. 

36
Q

What happens to foam concentrate when it is heated?

A

It becomes less viscous

37
Q

One major advantage of self educting nozzles is that:

A

The pressure drop is much lower than with most standard foam nozzle educators. This produces a more effective fire stream

38
Q

What is a jet ratio controller?

A

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.

39
Q

What percentage of concentrate does a jet ratio controller proportion?

A

66.5% solution

40
Q

What is the most common type of installed proportioner used in modern fire apparatus?

A

Around the pump proportioner

41
Q

What is a major advantage of using variable flow demand type balanced pressure proportioner?

A

The flow of concentrate matches the pressure demand

42
Q

AFFF foam solution can act as a cleansing agent. What must be done after using a FFF foam?

A

Thoroughly flush out the tank and pump to remove all foam, and then check the seals for proper lubrication.

43
Q

CAFS engines use high energy foam proportioning. How does this positively affect fire streams?

A

The streams are farther reaching.

44
Q

When should smoothbore nozzle’s be used in the application of foam?

A

Only when using class A foams from a CAFS

45
Q

What is the only nozzle that should be used with flouroprotein concentrates?

A

Air aspirating foam nozzles

46
Q

What is a physical feature about water aspirating devices (Nozzles) for foam application?

A

They are larger and longer

47
Q

Why would a mechanical blower (nozzle) be the best choice of equipment when an incident requires total flooding?

A

They produce foam with a very high air content.

48
Q

What is caused with a nozzle is placed too far above the eductor during form application?

A

Excessive elevation pressure is created

49
Q

When would a roll on method of applying foam be effective?

A

When fuel is ignited in a large, flat ground level surface.

50
Q

What foam application method might be used at an incident involving an above ground storage tank?

A

Rain down method

51
Q

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?

A

10:1 expansion ratio

52
Q

What are the guidelines for the online foam inductor to properly produce foam using the Venturi effect.

A

-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.

IFSTA Exam Prep (20 decks)

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