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21 Cards in this Set

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Define fire stream
a stream of water or other extinguishing agent after it leaves the fire hose and nozzle until it reaches the desired point.
List the purposes of fire streams:
a. Reduce high atmospheric temperature and/or dispense smoke and gases from a heated area in a confined space.
b. Reduce temp over an open fire in order to allow a closer proximity with attack line.
c. Protect firefighters and property from heat.
d. Create a barrier between fuel and fire.
Advantages of water as an extinguishing agent
» A relatively large amount of heat is required to change water into steam.
» The greater the surface area that water is exposed the more rapidly heat will be absorbed.
» When a water stream is broken into small particles, it absorbs heat and turns to steam more quickly.
» Water converted into steam occupies several hundred times is original volume.
Disadvantages of water as an extinguishing agent
» Considerable surface tension
» Reacts with certain materials.
» Freezes at normal winter temp.
» Low viscosity (thickness)
» Conducts electricity
» Steam burns.
At 500 F˚ water expands
to 2,400 to 1 (means every one cubic foot of water (7.48 gallons) will occupy a space of 2400 cubic feet when converted to steam.)
At 212˚ F water expands
1,700 to 1 (means every one cubic foot of water (7.48 gallons) will occupy a space of 1700 cubic feet when converted to steam.)
At 1,000 F˚ water expands
4,200 to 1(means every one cubic foot of water (7.48 gallons) will occupy a space of 4200 cubic feet when converted to steam.)
List the three types of fire streams and gpm operation
low-volume: less than 40 gpm, handline stream: 40 to 350 gpm, and master stream: greater than 350 gpm.
Solid stream hand held nozzles operate at
50psi
Solid stream for mater streams operate at
80psi
Solid stream advantages:
» Greater reach & penetration.
» Operate at less pressure and reduce nozzle reaction.
» Less likely to disturb thermal layer.
» Maintains better visibility for firefighters.
Solid streams disadvantages:
» Only one stream pattern available.
» Cannot be used with foam.
» Less heat absorption per gallon delivered.
Fog stream nozzles are design to operate at
100 psi at the base of the nozzle
Most fog nozzles are adjustable into:
1. Straight stream
2. Narrow fog stream (15 to 45 degrees)
3. Wide-angle fog stream (45 to 80 degrees)
Fog Stream Advantages
» Pattern can be adjusted.
» Amount of water can be adjusted.
» Can aid in ventilation.
» Greater surface area cover cause greater heat absorption.
Fog Stream Disadvantages
» Does not have as far as a reach as solid stream.
» Can be broken by the wind.
» Can cause steam burns and contribute to fire spread.
gpm
gallons-per-minute
psi
pounds-per-square-inch.
pressure is
the application of force.
Water hammer is
is the sudden surge of pressure in the water system resulting from the sudden stoppage of water flow through the system.
Nozzle reaction is
is the back pressure or kick back felt while water is being discharge from a nozzle.