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31 Cards in this Set

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  • Back
3.0a List the major parts of a water distribution system?
water pipes, storage facilities, pumping stations, valves, fire hydrants, meters, and other appurtenances.
3.0b Why must a continuous positive water pressure be maintained in a distribution system?
to protect the distribution system from the entrance of toxic and other undesirable substances.
3.1a What problems may be created by excessive pressures in a distribution system?
may damage customers facilities and plumbing fixtures, it may also create leaks in the distribution system..
3.1b What causes friction losses in pipes?

by the roughness of the inside of the pipe creating turbulence proportional to the velocity of the flowing water..
3.1c What conditions might cause thrust in a pipe?

can be caused at any point where water changes direction, increases velocity, or the flow decreases or stops..
3.1d Water hammer can be caused by what actions?

caused by the action of a pump suddenly starting or stopping or valves quickly opening or closing
3.1e During a pressure test, a pressure gage attached to a faucet in a home read 30 psi, what is the head pressure head in feet?

30 psi x 2.31 ft/psi= 69.3 ft

3.2a What determines the hydraulic adequacy for a distribution system?
the hydraulic adequacy of a distribution system is determined by the pressures that exist at various points in the system under the conditions of operation.

3.2b Why are booster pumps sometimes installed directly on mains?

to increase the available system pressure.

3.2c Why should construction of deadend water mains be avoided?

avoid the development of taste and odor problems, also stagnate water is created
3.3a How can the requirements for operational storage be reduced?
opp storage can be reduced by the use of wells.

3.3b What type of material is commonly used for large water transmission mains?

concrete with steel cylinders is commonly used for large water transmission mains..

3.4a How can the storage of water in covered distribution reservoirs aid disinfection?
it provides an extended contact time for effective disinfection

3.4b What precautions should be taken with distribution reservoir drains and overflows?

no cross connections to any sewer or other source of contamination and they should be screened..

3.5a What type of pump is used for water distribution systems
centrifugal pumps are commonly used for water distribution systems

3.5b What is the best source of power for distribution system pumps?

electric motors are the best source of power for distribution systems pumps because they are compact and well adapted to automatic control or remote operation..
3.60a Dead-end water mains can cuase what type of problems?
Can cuase taste and odor problems, and poor water conditions

3.60b List two advantages of grid or loop water distribution?

no dead ends, and greater flow of water to an area when there is a fire or other source of high demand because water is being carried to any spot from more that one direction..
3.61a list the forces water distribution systems pipes must be capable of resisting?
capable of resisting forces from backfill, weight of passing traffic, internal water pressures such as delivery pressure, surges, and water hammer..
3.61b list the important installation features of water distribution pipes

weight, jointing characteristics, available sizes, and ease of tapping the line.
3.62a how can the external corrosion of ductile-iron pipe be reduced?
application of bituminous coatings or a polyethylene wrap..

3.62b Steel pipe may be lined with what types of materials?

lined with a bituminous material, cement mortar or a epoxy coat..

3.62c What types of coatings may be applied to steel pipe?

maybe coated with epoxy or mastic, they can be galvanized, or protective wrap could be used..
3.62d list the major disadvantages of concrete pipe

pipe is heavy, hard to tap, needs special fittings, and may deteriorate in aggressive corrosive soils..

3.62e what are the disadvantage of asbestos-cement pipe?
disadvantages of asbestos-cement (AC) pipe include its low flexural strength in small sizes and its vulnerability to impact damage. its non-conductive, difficult to locate buried pipes or to thaw frozen pipes using electrical methods..

3.62f list 3 types of plastic materials used for plastic pipe?

plastic pipe may be made of PVC (polyvinyl chloride), PE (polyethylene), and PB (polybutylene)

3.62g what are the most common materials used for service lines?
services lines consist of copper, PVC, PE, PB..

3.62h why should existing lead service lines be replaced?

potential for toxic lead to enter the water.
3.63a list the basic requirements for a good pipe joint
watertight seal, easy installation, durability, and corrosion resistance
3.63b what types of joints are most commonly used for ductile-iron pipe?

push on and mechanical joints, flanged, restrained, flexible, and sleeve joints are also used..

3.63c what types of joints are used to join steel pipe?

steel pipe may be joined by bell and spigot lap weld joint, bell and spigot rubber gskt joint, harness joint, Carnegie shape rubber gskt joint, butt weld joint, butt strap joint weld, mechanically coupled joint, and flanged joint for bolting.