Transcript Fire Streams - Geronimo VFD

Fire Streams
Geronimo Vol. Fire Dept.
Extinguishing Properties of
Water
 Water extinguishes fires by
 Cooling
 Remove heat from the fire
 Smothering
 Absorb large quantities of heat
 Dilute oxygen
Heat Absorption
 Small particles absorb heat and
converts into steam more rapidly than
a compact form
 Example - same cubes of ice melt faster
then large cube of ice
 Fog stream verse straight stream
Water’s Expansion Capability
 At 212 F water expands approximately
1,700 times its original volume when
converted to stream
 Example - If a nozzle discharges 150
gallons a minute, 20 cubic feet of water
will be created. At 500 F that will
convert into 48,000 cubic feet of steam.
This will fill a room 50 feet wide by 96
feet long
Water’s Expansion Capability
 Steam will displace smoke and gases
and mess up the thermal balance.
 Insure that adequate ventilation is
available
 If ventilation is adequate
 Fire will be extinguished or reduced in size
 Visibility may be maintained
 Room temperature is reduced
Important Characteristics of
Water
 Readily available and inexpensive
 Water has a greater heat-absorbing capacity
than other common extinguishing agents
 Water changing into steam requires a
relatively large amount of heat
 The greater the surface area of the water
exposed, the more rapidly heat is absorbed
Pressure Loss/Gain
 Pressure Loss and Gain are effected by
 Friction loss
 Elevation
 Friction loss is caused by
 Hoses (length and diameter)
 Nozzles
 Adapters
 Elevation
 If nozzle is above the pump pressure is lost
 If nozzle is below the pump pressure is gained
Water Hammer
 Water hammer is the sudden stoppage
of water through fire hose or pipe
 This can damage water mains,
plumbing, fire hose, hydrants, valves,
and hose clamps
 Close valves and nozzles slowly to
prevent water hammers
Water Fire Stream Patterns
and Nozzles
 Low-volume streams
 Less then 40 gpm (booster hoselines)
 Handline streams
 40 to 350 gpm (1 1/2 to 3 in hose)
 Master streams
 350 gpm + (multiple 2 1/2 or 3 in hoses)
Water Fire Stream Patterns
and Nozzles
 Solid Stream
 Produced from a fixed orifice, smoothbore
nozzle
 Long reach
 Penetration
 50 psi at the nozzle for handlines
 80 psi at the nozzle for master streams
 No foam
Water Fire Stream Patterns
and Nozzles
 Fog Stream
 Composed of very fine water droplets
 Settings
 Straight streams
 Narrow-angle fog (15 to 45)
 Wide-angle fog (45 to 80)
 Operate at the set nozzle pressure
 Used mainly for interior attacks
Factors That Affect Reach
 Gravity
 Water velocity
 Fire stream pattern selection
 Water droplet friction with air
 Wind
Fog Nozzles
 Manually adjustable nozzles
 You set the gpm on the nozzle
 Automatic nozzles
 Pressure from the pump determines the
gpm
Fog Nozzle Advantages
 Dissipate more heat then solid stream
nozzles due to greater water surface
area
 Aids in ventilation
 Adjustable pattern
Maintenance of Nozzles
 Check the swivel gasket for damage or




wear
Look for external damage
Look for internal damage and debris
Check for ease of operation by
physically operating the nozzle parts
Check to make sure that the pistol grip
is secure
Foam
 Foam extinguishes and/or prevents fire by
 Separating
 Creates a barrier between the fuel and the fire
 Cooling
 Lowers the temp. of the fuel and adjacent surfaces
 Suppressing
 Prevents the release of flammable vapors and therefore
reduces the possibility of ignition or reignition
Class A Foam
 Used on ordinary combustibles
 Wildland and structure fires
 May be proportioned as needed
 From a dry (thick) foam to a wet (thin) foam
Class B Foam
 Used to help extinguish hydrocarbon fuel
fires
 Oil, fuel oil, gasoline, benzene, naphtha, jet
fuel, and kerosene
 Floats on top of the fuel
 Traps vapors in
 Keeps oxygen out
 Proportion is per manufacturer’s
recommendations
 Normally 3 to 6 percent
Proportioning
 Four methods
 Induction
 Injection
 Batch-mixing
 Premixing
Foam Application Techniques
 Roll-On Method
 Stray foam at the front edge of the burning fuel
 Bank-Down Method
 Stray foam on an elevated object in the fuel
 Rain-Down Method
 Stray foam in the air above the fuel and let it
rain down