Chapter 6 Flashcards
What factors effect the condition of the stream as it exists the nozzle?
Operating pressure, nozzle design and adjustment, condition of the nozzle orifice
What factors influence the fire stream from when it leaves the nozzle and when it reaches its destination?
Velocity, gravity, wind, friction with the air
What 3 types are of nozzles operated by the fire service?
Solid, fog, and broken stream
solid fire stream
Is produced with a fixed orifice and a smooth bore nozzle and stays together as a light stream with little spray or shower effect
What type of hose lines smooth bore nozzles?
Handling and master streams
How are solid stream nozzles designed?
Sothat water flowing through the nozzle is reduced gradually so that the water has a smooth shape at discharge. The smooth waterway helps maximize the reach of the stream.
What determines the flow and reach of as solid stream?
The size of the discharge and the nozzle pressure.
What psi should hand lines with a solid stream nozzle be operated at?
50psi
What psi should master streams with a smooth bore nozzle be operated at?
80psi
How do fog nozzles break streams of water in to finely divided particles?
That stream is driven up against an obstruction with sufficient force to diffuse the water and shatter the mass.
In a fog nozzle what does the pattern of deflection determine?
The forward velocity of the stream of water, the pattern of the final stream and the shape.
In what ways does fog nozzles produce fog streams?
Deflection at the periphery, impinging streams of water, or both.
What are periphery-deflected fog streams?
Are produced by deflecting the water around a circular stream inside the nozzle. Then the water is deflected by the outside barrel of the nozzle. The position of the stem relative to the barrel will determine the shape of the stream.
How do impinging stream nozzles break streams of water into five evenly divided particles?
By driving several sets of water together at an angle.
What angle of fog pattern do impinging stream nozzles most often provide?
Wide angle (but narrow is possible)
Besides impinging stream nozzles, what other kinds of nozzle can impinging jets be used?
Periphery deflected stream nozzles
What 4 things directly affect the reach of a fog stream?
The stream width, the size of the water droplets, the wind and the volume of water flowing.
What is a constant flow nozzle?
Is designed to flow a specific volume of water on all stream patterns at a specific discharge pressure.
How do continuous flow nozzles operate?
The exterior of the barrel rotates in order to adjust the flow pattern. However, the space between the deflecting stem and the interior throat of the nozzle remains the same, allowing for the same gallonage of water to be discharged on every pattern settings.
What are selectable gallonage nozzles?
Allow firefighters in the nozzle to select the flow rate at the nozzle based on the conditions encountered.
What is a disadvantage of the selectable gallonage nozzle when operating on the fire line?
The driver/operator must know what gallonage has been selected in order to calculate the correct discharge pressure.
What are adjustable fog nozzles?
A type of variable flow nozzle with the ability to change patterns while maintaining a constant flow. If the gallonage supplied to the nozzle changes the nozzle automatically changes to maintain the same pressure and pattern
What are most for nozzles designed to operate at?
100 psi
What are high pressure fog nozzles?
Nozzles that produce a stream with significant forward velocity but low volume.
What pressures do high pressure fog nozzles operate at?
Greater than 100 psi but not greater than 800 psi
Why are high pressure fog nozzles not recommended for structural firefighting?
Because of their low water flow 8-15gpm. They are often used asan impinging stream in wildland fire.
What is usually considered the maximum flow of a handline nozzle?
350 gpm
Why are nozzles that flow greater than 350 gpm not usually used as handlines?
The nozzle reaction produced by the greater Flows will be difficult/ dangerous for a fire fighter on a handline to handle
What nozzles flow greater than 350 gpm?
Master stream nozzles
What kinds of streams can be produced by master stream nozzles?
Fog and solid stream
What situations would require a master stream over a hand line?
Fires with heavy fire volume, when conditions require a defensive technique, limited number of personnel, when a farther reach is required for the water stream.
What are smooth bore master streams usually operated at?
80 psi
What pressure are fog master stream appliances usually operated at?
100 psi
What are the three types of master steam appliances?
