Chapter 16
class A foams are proportioned at ___ % or less
1
class B foams are proportioned from ___ to ___ %
1 to 6
maximum nozzle pressure for a master stream is ___
100 psi
most fog nozzles are designed to operate at a nozzle pressure of ...
100 psi
high expansion foam produces up to ___ parts of finished foam for every one part of foam concentrate
1000
when vaporized, a given volume of water will expand to ___ times its original volume
1700
a gallon of which foam concentrate will product the most foam?
1?
low expansion foam produces up to ___ parts of finished foam for every one part of foam concentrate
20
medium expansion foam produces up to ___ parts of finished form for every one part of foam concentrate
200
what is the range of flow from a 1" solid stream nozzle operated between 50 and 80 psi?
209-264 gpm
under actual fireground conditions, which angle of stream discharged produces the longest reach?
30-34 degrees
master streams are those that flow a minimum of ...
350 gpm
what is the maximum recommended flow from a handline?
350 gpm
a low volume stream discharges a maximum of ...
40 gpm
recommended nozzle pressure for a hand-held solid stream is ___
50 psi
if greater reach and volume are needed from a handheld solid stream, nozzle pressure may be safely increased to a maximum of ___
65 psi
what is the recommended nozzle pressure for most smooth bore master stream appliances?
80 psi
a foam's ability to reduce the surface tension of water will make it effective on class ___ fire
A
which foam is best suited for application with a standard fog nozzle?
AFFF
which is an advantage of a fog stream?
increased heat absorbing capacity
when a fog stream is at maximum reach, what will further increases in nozzle pressure produce?
increased volume
which one of these measures will increase friction loss?
increasing the velocity of the water in the hose
foam extinguishes through all of the following mechanisms EXCEPT ONE. CHOOSE THE EXCEPTION
inhibiting
what method of proportioning forces foam concentrate into the water stream?
injection
which is one of the foam proportioning methods?
injection
how does the low surface tension of class A foam enhance its extinguishing properties?
it causes water to penetrate fuel more easily
what effect does proportioning class A foam in a higher concentration have on the foam?
it creates thicker, dryer foam
which statement about a straight stream is correct?
it is discharged from an adjustable fog nozzle
which statement about an in-line foam eductor is correct?
it uses the venturi principle to draft foam concentrate
which statement about a foam nozzle eductor is correct?
its use may compromises firefighter safety
which is a polar solvent?
laquer thinner
a wide-angle fog pattern has ___ that a narrow-angle pattern
less velocity and reach
what is an advantage of a compressed air foam system (CAFS)?
long reach of hose streams
what is the effect of a surfactant?
lower surface tension
a water aspirating nozzle is designed for use with what kind of foam?
medium expansion foam
the forward velocity of a fire stream is directly generated by ___ pressure
nozzle
the velocity pressure at which water is discharged from a nozzle is ___ pressure
nozzle
which statement about an automatic fog nozzle is correct?
nozzle pressure remains constant despite variations in discharge rate
which on of these statements about foam is correct?
once foam application has begun, it should not be stopped until the fire is extinguished
which appliance mixes the correct amount of foam concentrate with water?
porportioner
portable foam extinguishers are examples of ___ foam systems
premixed
which form of foam proportioning is most commonly used with wheeled extinguishers?
premixing
unlike other nozzles, a manually adjustable fog nozzle permits the nozzle operator to select ___
rate of discharge
which is an advantage of a solid stream?
reach
what is an advantage of a low pressure fog nozzle?
reduced nozzle reaction
in applying class B foam, whether or not the fuel is ignited will affect the ___
required foam application rate
the latent heat of vaporization is the amount of heat ___
required to convert a substance from a liquid to a vapor
which foam application method should only be used for a pool of liquid fuel on the open ground?
roll on
in which method of foam application is a bank of foam formed on the ground in front of the flammable liquid pool and pushed over the flammable liquid by the continued application of foam?
roll-on
which nozzle control valve adjusts the stream pattern as well as controlling the flow?
rotary
foam's ability to ___ creates a barrier between the fuel and the fire
separate
which stream application will cause the lease expansion of the upper layer of fire gases in a compartment?
short pulses of wide-angle fog into the gas layer
past the point of breakover, water from a solid stream becomes ...
showers of spray
foam's ability to ___ prevents the release of flammable vapors
smother
the amount of heat required to raise the temperature of a specified mass of a material by one degree is the definition of ...
specific heat
what is NFPA terminology for a fog nozzle?
spray
what is NFPA terminology for a smooth bore nozzle?
straight tip
the rate of vaporization of water is increased the most by increasing the ___ of the water
surface area
what is a disadvantage of an in-line foam eductor?
the concentrate container must be kept close to the hose
what is the difference, if any, between a straight stream and a solid stream?
the type of nozzle producing the stream
what is a disadvantage of a fog streams?
they are more likely to disrupt thermal layering
which is an appropriate use for class B foam?
to suppress vapor emission from unignited fuels
how can friction loss be reduced?
use large hoseline
which statement about broken streams is correct?
used for basement and attic fires
by which process is a liquid rapidly turned into a gas?
vaporization
what is the function of stacked tips?
vary flow rate
what is the term for a thick, sticky foam?
viscous
which foam is best suited for discharge from a smooth bore nozzle?
CAFS / class A
compared to other stream types, solid streams ___
absorb less heat per gallon discharged
at which stage of foam production are bubbles formed?
aeration
which is the most effective appliance for generating low-expansion foam?
air-aspirating foam nozzle
which nozzle is suitable for use with fluoroprotein foam?
air-aspiring
an installed in-line eductor is a type of ___ proportioner
apparatus-mounted
a balanced pressure proportioner is a type of ___
apparatus-mounted proportioner
what is the most common nozzle control valve?
ball
which foam application method is commonly used for a fire a diked containment area around a storage tank?
bank-down
which foam application method is commonly used for transport vehicle accidents?
bank-down
what is adding foam concentrate to a fire apparatus tank called?
batch mixing
which form of proportioning is the least suitable for use with class B foam concentrates?
batch mixing
which is a hydrocarbon fuel?
benzene
which is a cellar nozzle?
bresnan
which is one of the major classifications of fire streams?
broken
which type of stream is most commonly used for fires in confined spaces?
broken
which nozzle is designed to be lowered through a hole cut in an overhead surface?
cellar
batch mixing is used most commonly for ...
class A foam
what is the primary mechanism by which water extinguishes fire?
cooling
as a nozzle is elevated above the pump, pressure at that nozzle ___
decreases
at a constant flow and pressure, as a fog nozzle pattern widens, the stream reach ___
decreases
what is a distinguishing feature of a constant gallonage fog nozzle?
delivers the same volume regardless of the type of stream pattern selected
steam generation ___ smoke
displaces
which type of class A foam would be most effective for structure protection in the wildland/urban interface?
dry
which method of foam proportioning relies on the venturi principle?
eduction
when water turns to steam, it immediately ___
expands
after aeration, the discharged foam product is called ___ foam
finished
for which application is high expansion form most appropriate?
flooding of confined spaces
water is the solution that is mixed with water and air to produce foam?
foam concentrate
what is the mixture of foam concentrate and water before air is added?
foam solution
what is the term for the effect on pressure as water is forced through hose, appliances, and fittings?
friction loss
the most efficient and effective use of water is achieved by matching the critical flow rate with the ___
heat release rate
a mechanical foam generator is designed for use with what kind of foam?
high-expansion foam
