Chapter 14 Flashcards
foam consists of fluorochemical and hydrocarbon surfactants combined with solvents to create a high boiling point
Aqueous film forming foam
Low energy foam systems impart pressure on the foam solution with the use of the:
main fire pump
proportioner used on large mobile apparatus installations, such as ARFF vehicles, and is one of the most accurate methods of foam proportioning?
Bypass-type balanced pressure proportioner
nozzle allows firefighters the option of operating fixed flow, selective flow, or automatic flow when applying a low expansion, short duration foam blanket?
Fog nozzles
released as fire fighting foam breaks down, providing a cooling effect on the fuel and suppressing the process of heat-producing oxidation
Water
In order to produce fire fighting foam, what three items must be educted or injected in correct ratios
Foam concentrate, water, and air
used to combat concealed space fires in cellars or other subterranean spaces?
High-expansion foam
examples of polar solvent fuels requiring the use of special polymeric fire fighting foam
Alcohol and ketones
Installed in-line eductors are most commonly used to proportion which class of foam
Class B
what happens to regular protein foams
They degrade more quickly and are becoming increasingly rare.
The formula of Class A form includes _____ that reduce the surface tension of water in the foam solution
hydrocarbon surfactants
Both of the basic types of medium- and high-expansion foam generators produce foam containing
high air content
In which of the following situations is it acceptable to mix together different manufacturers’ foam concentrates
If they are mil-spec concentrates
common handline nozzle used for foam application
fog nozzle
determined by the rate at which natural bacteria can degrade foam
Biodegradability
What is the commonly used guideline for proportioning Class A foam for exposure protection with standard fog nozzles
0.5 to 1.0 percent concentrate
explains why fuel and fire might consume a portion or the entire foam blanket
Inconsistent application time
In which of the following ways are durable agents similar to Class A foam
Both products are used in a similar fashion
What are the two basic types of medium- and high-expansion foam generators?
Water aspirating and mechanical blower
Viscosity, or the thickness and ability of a liquid to flow freely, is MOST likely to be affected by:
temperature
The act of mixing water with foam concentrate to form a foam solution is called
proportioning
A smooth bore nozzle is limited to application of which classification of foam
Class A foam from a CAFS
batch mixing
is potentially inaccurate
limitation of CAFS
In the event of a hose burst, compressed air will intensify the reaction of the hoseline.
Class B synthetic foam concentrate is made from:
a mixture of fluorosurfactants.
A type of in-line eductor that may be used to supply foam concentrate to a self-educting master stream foam nozzle is called a
jet ratio controller
Direct application is a method of attack that is BEST used with
Class A
designed to work in conjunction with proportioners to produce the best possible foam
Foam Nozzles
likely to affect the degree of expansion in a foam solution
Method of aeration
foam proportioner that is designed to be attached directly to the pump panel discharge or connected at some point in the hose lay
In-line foam eductors
variable-flow demand-type balanced pressure proportioners
consists of a variable speed mechanism driven electrically or hydraulically that operates a foam concentrate pump
What is the smallest type of foam storage container
Pails
Class A foam solutions do not retain their foaming properties when mixed in water for more than
24 hours
most common apparatus-mounted foam proportioner and consists of a small return (bypass) water line connected from the discharge side of the pump back to the intake side of the pump?
Around-the-pump proportioner
Which proportioning method uses premeasured portions of water and foam concentrate that are mixed in a container?
Premixing
In order to eliminate using pails or barrels to supply a foam eductor, fire apparatus equipped with onboard foam proportioning systems usually have _____ piped directly to the delivery system.
foam concentrate tanks
Regardless of the type of tank, what is one characteristic that all foam storage containers share
Airtight Storage
Because it forms a rigid coating that adheres well and is slow to drain, the best consistency of Class A foam for vertical surfaces is
Dry Foam
Which kind of nozzle inducts air into foam solution by a Venturi action and is the only nozzle that should be used with protein and fluoroprotein concentrates
Air-aspirating foam nozzles
Due to the low eduction rates on a CAFS apparatus, what is required to supply the fire stream at the rate of 0.1 to 1.0 percent
A variable flow rate sensing proportioner
is an element that affects the breakdown process of Class A foam?
Ambient air temperature
n some installed in-line eductor systems, a(an) _____ proportioner is installed to reduce the friction loss across the eductor.
bypass
What are Mil-Spec concentrates?
Foam concentrates manufactured to U.S. Military specifications
High-energy foam generating systems/CAFS differ from other methods because
they introduce compressed air into the foam solution prior to discharge into the hoseline.
described as the device that injects the correct amount of foam concentrate into the water stream to make the foam solution
Foam proportioner
When using the batch mixing proportioning method, frothing can be avoided by
slowly circulating water in the tank
has a pickup tube that is located in the center bore of the nozzle and uses a modified Venturi design to draw concentrate into its water stream
Self-educting master stream foam nozzle
method for Class B foam application involves directing the foam onto a vertical surface and allowing it to run down and spread across pooled fuel product?
Bank-down method
The minimum amount of foam solution that must be used on a fire per minute per square foot (square meter) of fire is called the:
application rate
Why is it important to avoid direct application of Class A foam to natural bodies of water
It can harm aquatic life.
following operating guidelines must be followed to achieve properly proportioned finished foam?
The flow in gallons per minute (L/min) through the eductor must not exceed its rated capacity.
is true about the adequate and/or inadequate production of foam when an in-line proportioner is used?
A partially closed nozzle will result in a flow rate that will not allow the creation of a Venturi effect.
Which proportioning method uses an external pump to force foam concentrate into the fire stream at the proper ratio in comparison to the flow?
Injection
is a disadvantage of durable agents
Once applied, surfaces coated with these products become very slippery for walking or driving
Driver/operators calculate the application rate available from a specific nozzle by:
dividing the flow rate by the area of the fire.
The process of foam decomposition results in the consumption of:
oxygen
For a portable foam application device, once foam concentrate and water have mixed to form a foam solution, the solution must be
aerated
Mixed with air
aerated
Mixed with water
proportion
3 things foam does
Separates
Cools
Suppresses
4 way foam is proportioned
Induction
Injection
Batch Mixing
Premixing
4 way foam is stored and size
Pail - 5 gal
Barrel 55 gal
Tote 275 gal
Apparatus Tank 20-200 gal
Foam tenders may carry up to
8000 gal of foam
Class A foam should avoid skin contact because is can be
corrosive
Common proportioning for Class A Foam
.2-.5 FIRE ATTACK with standard nozzles and CAFS
.3-.7 with air aspirating nozzles
.5-1 EXPOSURE protection with standard nozzles
Shelf life of Class A and B Foam
A - 20 yrs
B - 20-25 yrs
Foam which is safer for the environment
Protein Based Foams
Foam Expansion air/solution ratio for low, medium, high
Low- 20:1
Med - 20:1-200:1
High - 200:1- 1000:1
Alcohol resistive properties will be effective for approx.
15 minutes
Uses a modified venturi design, capable of delivering 14,000 gpm
Self-Educting Master Stream
3000 feet of supply
50ft of elevation
66.5 solution
Jet Ratio Controller
Medium and High Expansion ratios
20: 1 - 200:1
200: 1 - 1000:1
Standard rule that dictates the discharge orifice be no greater than
half the diameter of the hose
Only nozzle that can be used with fluoroproteins
Air-Aspirating Fogs
Fog Nozzle low expansion ration
2:1 - 4:1
