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Absolute Pressure
The measurements of pressure, including atmospheric pressure. measured in PSI absolute
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Automatic/Constant Pressure Nozzle
nozzle with a spring mechanism built in that reacts to pressure changes and adjusts the flow and resultant reach of the nozzle
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Available Flow
amount of water that can be moves to extinguish the fire, depends on the water supply, pump(s) and their capabilities, and the size and length of the hose.
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Bresnan Distributor
a device used to fight fire in basements or cellars when firefighters cannot make a direct attack on the fire; has 6 or 9 solid tips or broken stream openings designed to rotate in a circular spray pattern
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Combination Fire Attack
a blend of the direct and indirect fire attack methods, with firefighters applying water to both the fuel and the atmosphere of the room
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Combination Nozzle
spray nozzle that is capable of providing straight stream and spray patterns, which are adjustable or variable by the operator. most commonly used nozzle
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Constant/Set Volume Nozzle
nozzle with one set volume at a set pressure. forexample, 60 gpm at 100psi - the only adjustment is pattern
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Direct Fire Attack
an attack on the fire made by aiming the flow of water directly at the material on fire (directly at the seat)
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Discharge Flow
Total amount of water flowing from the discharge side of the pump
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Fire Stream
the water or other agent as it leaves the hose and nozzle toward its objective, usually the fire
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Flow
the rate or quantity of water delivered, usually measured in gpm or lpm (1gmp=3.785lpm)
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Fog Nozzle
delivers either a fixed spray pattern of variable combination of straight stream and spray patterns
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Friction
caused by the rubbing of materials against each other while in movement and converts or robs some of the movement energy into heat energy
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Friction Loss
measurement of friction in a system such as hoseline
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Gauge Pressure
measures pressure without atmospheric pressure. measured in PSI or PSIG
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Head Pressure
measures the pressure of a column of water in feet. gain or loss results when water is being pumped above or below the lvl of the pump. a head of 2.31 ft = 1 psi
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Hydraulics
the study of fluids at rests and in motion
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Indirect Fire Attack
an attack made on interior fires by applying a fog stream into a closed room or compartment, thus converting the water into steam to extinguish the fire
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Needed/Required Flow
estimate of the amount of water required to extinguish a fire in a certain time period. based on the type and amount of fuel burning
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Nozzle
a tapered or constricted tube used to increase the speed or change the direction of water or other fluids
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Nozzle Flow
the amount of volume of water that a nozzle will provide. measured in gpm or lpm
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Nozzle Pressure
the pressure required to effectively operate a nozzle. always measured in PSI or kilopascals
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Nozzle Reach
the distance the water will travel after leaving the nozzle.
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Nozzle Reaction
the force that makes the nozzle move in the opposite direction of the water flow.
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Piercing Nozzle
originally designed to penetrate the skin of aircraft and now has been modified to pierce through building walls and floors
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Pump Operator
generic term to describe the person responsible for operating a fire apparatus pump.
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Solid Stream Nozzles
type of nozzle that delivers an unbroken or solid stream of water to the fire. AKA solid tip, straight bore, or smooth bore
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Straight Stream
nozzle pattern that creates a hollow stream, similar in shape to solid stream pattern, but the straight stream pattern must pass around the baffle of the nozzle.
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Stream Shape
the arrangement or configuration of the water or other agent droplets as they leave the nozzle
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Vacuum (Negative) Pressure
the measurement of the pressure less than atmospheric pressure, which is usually read in inches of mercury (in. Hg or mm Hg) on a compound gauge
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Variable, Adjustable, or Selectable Gallonage Nozzle
nozzle that allows the nozzleperson to select the flow, with usually 2 or 3 choices, and the pattern
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Velocity Pressure
The forward pressure of water as it leaves an opening
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Water Curtain Nozzle
designed to spray water to protect exposures against heat by wetting the exposure's surface
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4 Elements That Affect Fire Stream
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Breakover
when water leaving the nozzle starts to fall over and break apart
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Handlines use tips from ___ to ___ inches at ___ PSI.
3/4 to 1 1/4 inches at 50 PSI
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Masterstreams use tips sizes of ___ inches and larger at ___ PSI
1 1/4 inches at 80 PSI
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Why are small lines popular to use?
- ease of mobility
- number of personnel required to operate
- their ability to extinguish one to three typical rooms of fire with their flow
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The method of stream application or fire attack depends on what?
- the fire's fuel
- the fire's location
- suppression equipment of the FD
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When should you never use an indirect fire attack?
when there is a possibility of people in the room
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1 cubic foot of water = ____ cubic feet of steam at 212F
1,700
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Effective fire streams will these noticeable results when applied to a fire.
- heat reduction
- flame reduction
- smoke reduction
- fire location becomes tenable
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What is the equation for engine pressure (also called pump discharge pressure)?
EP=NP+FL+/-E+SA
engine pressure = nozzle pressure + friction loss +/- elevation + special appliances
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Nozzle pressure for smooth bore handline
50 PSI (345 kPa)
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nozzle pressure for fog handline
- normal:100 PSI (690kPa)
- mid: 75 (517 kPa)
- low: 50 (345 kPa)
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nozzle pressure for smooth bore master stream
80 PSI (552 kPa)
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nozzle pressure for fog master stream
100 PSI (690 kPa)
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What is the equation for nozzle reaction on a smooth bore nozzle?
NR=1.57xD2xNP
Nozzle reaction = 1.57 x diameter of nozzle tip in inches, squared x nozzle pressure
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What is the equation for nozzle reaction on a fog nozzle?
NR=gpm X the square root of nozzle pressure X .0505
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What is the equation for friction loss?
FL = Q2 x C x L
Friction loss = quantity of water in hundreds of gallons per minute X friction loss coefficient for the diameter of the hose X length of the hose is hundreds of feet
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Coefficient Value for 1 1/2 inch hose
24
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Coefficient Value for 1 3/4 inch hose
15.5
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Coefficient Value for 2 inch hose
8
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Coefficient Value for 2 1/2 inch hose
2
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Coefficient Value for 3 inch hose with 2 1/2 inch couplings
0.8
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Coefficient Value for 4 inch hose
0.2
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Coefficient Value for 5 inch hose
0.08
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Coefficient Value for 6 inch hose
0.05
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What is normally the cause of ineffective fire streams?
improper pump or nozzle operations
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Elevation is usually rounded to ___ PSI per foot or ___ PSI per floor or 10 feet for practical fireground purposes.
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