Ch.7 Fire Hose Nozzles And Flow Rates Flashcards
What 2 things determine the flow and stream reach from a solid stream nozzle?
The nozzle pressure
The size and f the discharge opening
What Psi should a solid stream nozzle be operated ad for a hand line and a Masters stream device?
Handling - 50 psi
Master stream- 80
What is the formula for determining the amount of water being discharged from a solid stream nozzle?
GPM = 29.7 * d^2 * √NP
29.7 = constant d = diameter of orifice in inches NP= nozzle pressure in psi
The line bounding a rounded surface
Periphery
A turning from a straight line or given course
Deflection
To strike or dash about or against; Clashing with a sharp collision; to come together with Forrest
Impinge
Name 4 things the reach of the fog stream is directly dependent on.
The width of the stream
The size of the water droplets
Wind
The amount of water flowing
What is a constant flow nozzle designed to do?
Flow a specific amount of water at a specific nozzle discharge pressure on all stream patterns
Constant flow nozzles discharge the same amount of water regardless of?
The pattern setting
Most constant flow nozzles are designed to operate at a nozzle pressure of?
100psi
This nozzle allows the firefighter to select a flow rate at the nozzle
Adjustable gallonage nozzle or manually adjustable nozzle
Most of the adjustable gallonage nozzle are designed to operate at
100psi
The minimum flow setting for interior structural firefighting is?
95-100gpm
Automatic nozzles have the ability to
Maintain the same nozzle pressure
If the Gallonage supplied to the automatic nozzle changes the automatic nozzle…
Maintains approximately the same nozzle pressure and pattern.
How is the feature from the last card possible?
By a baffle that moves automatically varying the spacing between the baffle and the throat
Name two ways you might know that your pump is starting to cavitate
And what can be done?
Pump starts to speed up or becomes erratic
Supply hose becomes soft and begins to collapse
Try backing off the throttle slightly
No matter how much the pump discharge pressure is above, an automatic nozzle maintains a constant pressure of?
How does it do this?
100
By automatically enlarging it’s effective opening size (within the range of the nozzle) to match the flow.
High pressure fog nozzles operate at pressures up to?
800 psi
High pressure fog nozzles generally only flow how much gpm?
8-15 gpm
Generally, what is the maximum amount of water that can safely flow through a hardline nozzle?
350 gpm
Smoothbore and fog master streams operate at?
What gpm do master streams usually flow at?
Sb= 80 psi
Fog= 100 psi
350gpm or greater
Name 4 basic master streams
Monitor
Turret pipe
Deluge set
Elevated master stream
Which master stream can’t have the direction or angle changed while shooting water?
Deluge set
This master stream is supplied by permanent piping from the pump
Turret pipe
Stream direction and angle can be changed with this master stream while shooting water
Monitor
If greater reach and volume on a smooth note nozzle is desired you can raise the nozzle pressure to ___ without it becoming unmanageable.
65 psi
What is the formula for calculating the nozzle reaction for solid stream nozzles
NR= 1.57 * d^2 * NP
Name the rule of thumb formula for getting an approximate amount of nozzle reaction for a solid stream nozzle.
NR= Q/3
Where Q is the total flow of water in gpm through the nozzle
So if your flowing 300 gpm out of a solid stream nozzle you probably have around 100 pounds of nozzle reaction.
What is the formula for calculating the nozzle reaction for fog nozzles?
NR=0.0505 * Q * square root of NP
Where Q is the gpm and np is nozzle pressure
Name the rule of thumb formula for getting an approximate amount of nozzle reaction for a fog stream nozzle.
NR= Q/2
So if your shooting 300 gpm than you have approximately 150 pounds of nozzle reaction
