Chapter 6 Hose Nozzles And Flow Rates Flashcards
What affects the condition of the stream as it leaves the nozzle:
Operating pressure nozzle design and adjustment, condition of the nozzle as well
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Until it reaches its destination the fire stream is influnced by:
Velocity, gravity, wind, and friction with the air
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The fire service operates 3 types of nozzles to produce three basic fire streams, they are:
Solid, fog, and broken
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A solid stream is produced with a:
Fixed orifice and a smooth bore nozzle
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The flow and reach of a solid stream is determined by:
The pressure and size of the discharge orifice
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Solid stream nozzles should be operated at…..psi and master stream appliances should be operated at….. Psi
50/80
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Gpm formula is:
29.7 X d2 x sqroot of NP
D2 = diameter of the orifice in inches
Np is nozzle pressure in psi
Pg 195
On fog nozzles a wide angle deflection produces:
A narrow angle deflection produces:
Wide fog pattern produced by wide deflection
Narrow fog pattern produced by a narrow deflection
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A fog stream may be produced by deflection at the:
Periphery, by impinging jets of water, or a combination of these
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The position of the stem relative to the barrel will determine the:
Shape of the fog stream
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Impinging stream nozzles most often provide a:
Wide angle fog pattern
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THe reach of the fog stream is directly related to it:
Width, the size of the water particles, the wind, and the volume of water flowing
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A constant flow nozzle is designed to flow:
A specific volume of water on all stream patterns at a specific nozzle discharge pressure
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Most constant flow nozzles are designed to operat at a nozzle pressure of….. Psi however some nozzles may operate at….. Psi
100/50
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Selectable gallonage nozzles allow the firefighters operating the handline to select the:
Flow rate to suit fire and operating conditions
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Selectable gallonage nozzles are designed to flow the gallonage indicated at….. Psi nozzle pressure
100
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Automatic nozzles are a type of variable flow nozzle with the ability to:
Change patterns while maintaining the same nozzle pressure
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High pressure fog nozzles operate a pressures up to…. Psi and deliver a significant forward velocity but relatively low:
800 psi
Low water volume
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High pressure fog nozzles are best suited for……. Firefighting and only operate at… To …. Gpm
Wildland firefighting and operate at 8/15 gpm
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Nozzles for use on handlines may be …. Or ….. Or …… Design ranging in size from 3.4 inch to a 3 inch diameter hose nozzle. Generally …. Gpm is maximum flow for a handline
Solid, fog or broken stream
350 gpm
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Generally ….. Gpm is the maximum flow for a handline:
350
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Master stream nozles are capable of water flow in excess of 350 gpm and must be properly….. For safe operation:
Secured
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Master stream appliances are generally operated during incidents where handlines would be:
Ineffective, conditions require a defensive posture, or personnel are limited.
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Smooth bore streams are generally operated at …. Psi nozzle pressure while fog appliances are generally operated at…. Psi
80/100
The three basic types of master streams appliances are:
Fixed, combination, portable:
Fixed- deck guns permantely mounted to the apparatus
Combination-can be used on a off the vehicle
Portable- stored on apparatus and removed to use on scene
Cellar nozzles are also referred to as:
Distributors
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Piercing nozzles also called_________ are commonly used in:
Penetrating nozzles are used in aircraft fire fighting, car fires, or to apply water to voids, attics, or other areas inaccessible to standard fire streams
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Chimney nozzles flow only________ gpm at 100 psi
1.5-3 gpm
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Nozzle reaction:
The counterforce pushing back against firefighters operating the hoseline as water is discharging
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Nozzle reaction formula:
NR=1.57 x d2 x np
D= nozzle diameter in inches
Np = nozzle pressure in psi
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Nozzle reaction for fog stream nozzles formula:
NR= 0.0505 x q x sqroot NP
Q= total flow through the nozzle in gpm
Np = nozzle pressure in psi
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