Transcript Chapter 11

Nozzles and Fire Streams
1
Introduction
 Fires usually extinguished by water
 Water delivered using nozzles and fire
streams
 Nozzle selection important
2
Definition of Fire Stream
 Fire stream
 Four elements affect stream:
 Pump
 Water
 Hose
 Nozzle
 Proper stream
 Sufficient volume
 Pressure
 Direction to reach its target
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Nozzles
 Nozzles:
 Solid stream and fog
 Combination nozzles:
 Straight stream or adjustable spray
 Nozzle pressure
 Nozzle flow
 Nozzle reach
 Stream shape
 Nozzle reaction
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Nozzles showing the stream shape for straight,
solid, and wide pattern streams.
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Solid Tip or Stream
 Deliver unbroken stream of water
 Solid stream nozzle
 Flow a factor of tip size at a certain nozzle
pressure
 Minimal effect of room’s thermal balance
 Disadvantages:
 Lack of volume control
 Lack of fog protection
 Higher nozzle reaction
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Fog Nozzles
 Deliver fixed or variable spray pattern
 Fog provides better heat absorption
 Hydraulic ventilation
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Variable combination fog nozzle patterns. From top to
bottom: straight stream, narrow fog, and wide fog.
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Parts of a fog nozzle.
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Straight Stream
 Creates a hollow type stream
 Must pass around the baffle of the nozzle
 Creates an opening in the pattern
 May allow air into the stream and reduce its reach
 Newer designs have hollow effect from the
tip.
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Comparison of (A) straight and (B) solid streams at tip.
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Special Purpose
 Not often used
 Cellar nozzles and Bresnan distributors
 Piercing nozzles
 Modified to pierce through building walls and
floors
 Water curtain nozzle
 Sprays water to protect against heat exposure
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(A)
(B)
(A) Cellar nozzle and (B) Bresnan distributor.
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Piercing nozzle.
Water curtain nozzle.
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Nozzle Operations
 Solid tip nozzles easy to operate
 Nozzle size and tip selection
 Fog nozzles with rotating valves
 Gallonage and pattern adjustments
 Fog nozzles have more applications than
smooth bore nozzles.
 Review Chapter 10.
 Most hoselines operated from crouching or
kneeling position
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Small-Diameter Handlines
 Typically 38, 45, or 50 mm (1½, 1¾, or 2
inches) in diameter
 Flow from 400 to over 1,000 L/min (100 to
over 250 gpm)
 When flowing at lower volumes, operated by
one person
 Fog and solid tip nozzles can be used for
small lines.
 Ease of mobility
 Number of personnel
 Extinguishing ability
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Medium-Diameter
Handlines
 65 to 77 mm (2½-inch or 3-inch hose)
Solid tip and fog nozzles
 Flow from 625 to 1,200 L/min (165 to 325
gpm )
 65 mm (2½-inch) hose is standard size
hoseline
 Large commercial structures
 Require two or more personnel to
operate
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Master Stream Devices
 Capable of 1,400 L/min(350 gpm)
 Artillery of fire service
 Large volumes of water
 Apparatus-mounted or secured properly
 One person to operate
 Lack of mobility
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Stream Application, Hydraulics, and
Adverse Conditions
 Applications of fire streams vary
 Method of fire attack
 Conditions encountered
 Including environmental factors
 Water supply
 Proper pressure and flow
 Hydraulics
 Improper hydraulic calculations are the leading
cause of poor fire streams
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Direct, Indirect, and
Combination Attack
 Direct fire attack
 Indirect fire attack
 Combination attack
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Firefighter directly attacking a fire.
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Firefighter using indirect attack by applying water into
room and then closing the door.
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Basic Hydraulics, Friction
Loss, and Pressure Losses in
Hoselines
 Hydraulics
 Pressure
 Flow
 Moving water through hoselines,
nozzles and appliances requires forces
that act positively and negatively to
achieve flow.
 Mass
 Pressure
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Friction Loss
The loss of energy from the turbulence, or
rubbing, of the moving water through the
hose
 Pump operator compensates for friction
loss by increasing the pump pressure for
the correct pressure to the nozzle.
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Friction
Loss
Principles
 Friction loss is based on four principles:
 Friction loss varies directly with the length of the hose if
all other variables are held constant.
 Friction loss varies approximately with the square of the
flow.
 When the flow remains constant, friction loss varies
inversely with the hose diameter.
 For any given velocity, the friction loss will be about the
same regardless of the water pressure.
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Pump Discharge Pressure
 Discharge pressure of a pump: PDP = NP +
FL ± E + A
 Pump Discharge Pressure
 Nozzle Pressure
 Friction Loss
 Elevation
 Appliance loss
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Example for friction loss and pump discharge pressure calculations.
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Adverse Conditions
 Two types: natural and man-made
 Natural
 Wind and wind direction
 Rain, snow, hail, tree branches, wires
 Gravity and air friction
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Lessons Learned
 Fire streams
 Solid tip and fog nozzles
 Nozzle should match fire conditions and department
resources
 Correct hydraulics calculations
 Effective use of nozzles and fire streams on the
fireground
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