Chapter 7 Fire Hose Nozzles and Flow Rates Flashcards
Solid stream nozzles are designed to produce a stream as ___ as possible with little shower or spray.
compact
What characteristic does a solid stream nozzle have that other streams may not?
Superior reach
Solid stream nozzles may be used on:
A. handlines.
B. portable master streams.
C. elevated master streams.
D. all of the above.*
Solid stream nozzles are designed so that the shape of the water in the nozzle is gradually reduced until it reaches a point a short distance from the outlet; at this point, the nozzles becomes a cylindrical bore whose length is:
one to one and one-half times its diameter.
Which of the following can significantly alter stream shape and performance?
A. The length of the nozzle
B. The position of the nozzle
C. The diameter of the hoseline
D. Alteration or damage to the nozzle*
The size of the discharge opening and ___ determine the flow and stream reach.
nozzle pressure
Solid stream nozzles should be operated at ___ psi (kPa) on handlines.
50 psi (350 kPa)
Solid stream nozzles should be operated at ___ psi (kPa) on master stream devices.
80 psi (560 kPa)
Fog streams may be produced by deflection at the periphery, by impinging jets of water, or by:
a combination of deflection and impingement.
Periphery-deflected streams are produced by deflecting water from the periphery of:
an inside circular stem in a periphery-deflected fog nozzle.
In a periphery-deflected fog stream nozzle, the shape of the stream is determined by the relative position of the deflecting stem and ___ of the nozzle.
the exterior barrel of a fog nozzle.
What type of fog nozzle drives several jets of water together at a set angle to break the water into a fog stream of finely divided particles?
Impinging stream
Why are fog patterns easier to handle than solid or straight stream patterns?
The reaction forces largely counterbalance each other.
Which types of fog nozzle are designed to flow a specific amount of water at a specific nozzle dischage pressure on all stream patterns?
Constant flow nozzles
Which types of fog nozzle have a number of constant flow settings, enabling the firefighter to select a flow rate that best suits the existing conditions?
Manually adjustable nozzles
Which types of fog nozzle are the most common variable flow nozzles in use today?
Automatic nozzles
Which types of fog nozzle develop a fog stream with considerable forward velocity but deliver a relatively low volume of water?
High-pressure nozzles
Which types of fog nozzle maintain approximately the same nozzle pressure and pattern even if the gallonage supplied to the nozzle changes?
Automatic nozzles
Which types of fog nozzle is NOT recommended for structural fire fighting?
High-pressure nozzles
Which types of fog nozzle discharge the same volume of water regardless of the pattern setting?
Constant flow nozzles
Which types of fog nozzle supply the selected flow at the rated nozzle discharge pressure?
Manually adjustable nozzles
Which types of fog nozzle serve as a pressure regulator for the pumper as lines are added or shut down, ensuring that all available water may be used continuously?
Automatic nozzles
Which types of fog nozzle are best suited for fighting wildland fires?
Manually adjustable nozzles