Fire Apparatus Pump Theory

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Fire Apparatus Pump Theory

• Section 180

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Introduction

• Types of pressure encountered in the fire service
• Identify the types of fire pumps components of
  pumps
• Identify the function, theory, principles of
  operation of fire pumps

180-1.00
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Types of pressures encountered in the fire service

• Static pressure
• Residual pressure
• Flow pressure
• Normal operating pressure
• Negative pressure

180-1.01
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Static pressure

• The pressure exerted in all directions
• at a point in a fluid at rest

Static pressure is stored potential energy that
is available to force water through a pipe,
fittings, fire hose adapters
180-1.01a
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Residual pressure

• The pressure remaining in a system while water is
  flowing

The total available pressure not used to
overcome friction or gravity while forcing water
through pipes, fittings, fire hose adapter
180-1.01c
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Flow pressure

• The forward velocity pressure at a discharge
  opening when water is flowing

The rate of flow velocity of the water coming
from the discharge opening produces this force
called velocity or flow pressure
180-1.01d
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Water pressure
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Normal operating pressure

• The pressure found in the water distribution
  system during normal consumption demands

Occurs when some water is flowing in the system
180-1.01b
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Grid system
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Negative pressure

• Also called vacuum . Pressure that is less than
  atmospheric pressure

Negative pressure in the fire service is the
result of drafting operations, which results
from removing all the air from the pump using
atmospheric pressure to lift water from a source
lower than the pump
180-1.01e
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Terms related to the basic principles of fire
service hydraulics
Atmospheric pressure the atmosphere that
surrounds the earth has depth density exerts
pressure upon everything on earth
Capacity The maximum amount of water a pump
will deliver at the indicated pressure
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Displacement Movement of a given amount
of a fluid w/ each stoke of a pump
Flow GPM Gallons per minute, the
measurement of the amount of water
moved through a fire pump
Friction loss Loss of pressure created by the
turbulence of water moving against the
interior walls of the hose or pipe.
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Friction loss ex 1
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Friction loss ex 2
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Head Pressure (gain of loss) Water pressure
due to elevation. For every 1 increase in
elevation, 0.434 psi is gained. 1 M in
height 10 kPa is gained
Hydrant pressure The force of water when
it enters the pump from the
distribution system
Net engine pressure The actual amount of
pressure being produced by the pump
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Nozzle reaction The counterforce directed
against the people or device holding a nozzle
by the velocity of water being discharged
Pound per square inch PSI -
Pump discharge pressure The actual
velocity pressure (measured in PSI) if the
water as it leaves the pump enters the
hose line.
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Vacuum A pressure that is less than
normal atmospheric pressure
Velocity The rate of motion of a particle
in a given direction, speed
Water hammer When the flow of water is
suddenly stopped, the resulting surge is
referred to as a water hammer
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Water hammer
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Break
Break Time!!
Thank Goodness
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The firefighter shall identify describe the
following guages
Compound gauge A gauge connected to the intake
side of the pump that is capable of measuring
positive negative intake pressures
Discharge/pressure gauge A gauge on the
discharge side of the pump that registers the
pump discharge pressure
180-1.03
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Suction
Pressure
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Pressure loss
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Flow chart
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