5. Principles Of Water Flashcards
Force per unit area
Pressure
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A simple measurement of weight and is expressed in pounds or newtons
Force
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Any influence that causes a change in the speed, direction, or shape of a substance.
Force
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First principle of water:
Fluid pressure is PERPENDICULAR to any surface on which it acts.
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Second principle of water:
Fluid pressure at a point in fluid at rest is the SAME intensity in ALL DIRECTIONS.
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Third principal of water:
PRESSURE applied to a CONFINED fluid is transmitted EQUALLY in all directions.
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Fourth principal of water:
The pressure of a liquid in an open vessel is proportional to its DEPTH.
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Fifth principle of water:
The pressure of a liquid in open vessel is proportional to the DENSITY of the liquid.
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These devices allow those lines on the lower floors to be more easily controlled, while allowing the high pressure required to access upper floors.
Pressure-regulating devices
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Sixth principle of water:
The pressure of a liquid at the bottom of a vessel is INDEPENDENT OF THE SHAPE of the vessel.
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Refers to the height of water supply above the discharge office.
Head
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Stored potential energy available to force water through pipes, fittings, hose, and adapters.
Static pressure
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Portion of the total available pressure not used to overcome friction loss or gravity while forcing water through pipes, fittings, hose, and adapters.
Residual pressure
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Refers to the centerline of the pump or the bottom of a static water supply source above or below ground level
Elevation
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The rougher the inner surface of the pipe (commonly referred to as____)the greater the friction loss will be.
Coefficient of friction
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First principle of friction loss:
Friction loss varies directly with the LENGHT of the hose or pipe.
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Second principle of friction loss:
Friction loss varies u with the square of the increase in VELOCITY of flow.
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Third principal of friction loss;
Friction loss varies inversely as the fifth power of the DIAMETER of the hose.
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Fourth principal of friction loss:
For a given velocity, friction loss is approximately the same, regardless of the pressure on the water.
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_____pressure will always be greatest near the source of supply and lowest at the furthest point in the system.
Flow
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If the velocity is increased beyond this point, the friction will become so great that the entire system is agitated by resistance. This agitation causes a degree of turbulence known as:
Critical velocity
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Water may be treated by:
4things
Coagulation
Sedimentation
Filtration
Addition of- chemicals/bacteria/other organisms
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A fire hydrant that receives water from two or more directions
Circulating feed or looped line
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Grid arrangement of smaller main serving individual fire hydrants and blocks of customers.
Distributors
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Valves in private fire protection systems are usually of this type
Indicating valve (post)
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Two common indicator valves are:
Post indicator valve
Outside screw and yoke
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Most common type of valve used on most public water distribution systems
Nonindicating /Gate valve
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_______gate valve should be marked with a number indicating the number of turns necessary to completely close the valve.
Nonrising-stem
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The average amount of water used PER DAY based on the total amount of water used in a water distribution system over the period of ONE YEAR.
Average daily consumption (ADC)
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The maximum total amount of water that was used during any 24 HOUR interval within a 3 YEAR PERIOD.
Maximum daily consumption (MDC)
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Maximum amount of water used in any ONE HOUR interval over the course of A DAY.
Peak hourly consumption (PHC)
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