fire apparatus pump theory 1
DESCRIPTION
fire apparatus pumpTRANSCRIPT
Introduction 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
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Types of pressures encountered Types of pressures encountered in the fire servicein the fire service
Static pressure
Residual pressure
Flow pressure
Normal operating pressure
Negative pressure
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Static pressureStatic pressure
Static pressure is stored potential energy that is available to force water through a pipe, fittings, fire hose & adapters
The pressure exerted in all directions at a point in a fluid at rest
180-1.01a
Residual pressureResidual pressureThe 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
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Flow pressureFlow pressureThe forward velocity pressure at a
discharge opening when water is flowing
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The rate of flow {velocity} of the water coming from the discharge opening produces this force called velocity or flow pressure
Normal operating pressureNormal operating pressureThe pressure found in the water
distribution system during normal consumption demands
Occurs when some water is flowing in the system
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Negative pressureNegative 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
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Terms related to the basic Terms related to the basic principles of fire service hydraulicsprinciples 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
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.
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
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.
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
The firefighter shall identify & The firefighter shall identify & describe the following guages: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
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